Biomimetic triphasic silk fibroin scaffolds seeded with tendon-derived stem cells for tendon-bone junction regeneration

The regeneration of tendon and bone junctions (TBJs), a fibrocartilage transition zone between tendons and bones, is a challenge due to the special triphasic structure. In our study, a silk fibroin (SF)-based triphasic scaffold consisting of aligned type I collagen (Col I), transforming growth factor β (TGF-β), and hydroxyapatite (HA) was fabricated to mimic the compositional gradient feature of the native tendon-bone architecture. Rat tendon-derived stem cells (rTDSCs) were loaded on the triphasic SF scaffold, and the high cell viability suggested that the scaffold presents good biocompatibility. Meanwhile, increased expressions of tenogenic-, chondrogenic-, and osteogenic-related genes in the TBJs were observed. The in vivo studies of the rTDSC-seeded scaffold in a rat TBJ rupture model showed tendon tissue regeneration with a clear transition zone within 8 weeks of implantation. These results indicated that the biomimetic triphasic SF scaffolds seeded with rTDSCs have great potential to be applied in TBJ regeneration.

[Perioperative management of wounds associated with secondary sternal osteomyelitis and/or mediastinitis after sternotomy and its clinical effects]

Objective: To investigate the perioperative management of wounds associated with secondary sternal osteomyelitis and/or mediastinitis after sternotomy, and to evaluate its clinical effects. Methods: This study was a retrospective observational study. From January 2017 to December 2022, 36 patients with wounds associated with secondary sternal osteomyelitis and/or mediastinitis after sternotomy who were conformed to the inclusion criteria were admitted to the Burn Center of PLA of the First Affiliated Hospital of Air Force Medical University, including 23 males and 13 females, aged 25 to 81 years. Preparation for surgery was made. For patients with suspected retrosternal mediastinal abscess cavity, all cancellous bone of the unhealed sternum was bitten off to fully expose the retrosternal mediastinum, remove the source of infection and granulation tissue, and to fill the sternum defect with flipped unilateral pectoralis major muscle. For patients who had no retrosternal mediastinal infection but had fresh granulation tissue in unhealed sternal wounds, the necrotic tissue and a small amount of necrotic sternum were palliatively removed, and bilateral pectoralis major muscles were advanced and abutted to cover the sternal defect. After the skin in the donor area was closed by tension-relieving suture, continuous vacuum sealing drainage was performed, and continuous even infusion and lavage were added 24 hours later. The thorax was fixed with an armor-like chest strap, the patients were guided to breathe abdominally, with both upper limbs fixed to the lateral chest wall using a surgical restraint strap. The bacterial culture results of wound exudation specimens on admission were recorded. The wound condition observed during operation, debridement method, muscle flap covering method, intraoperative bleeding volume, days of postoperative infusion and lavage, lavage solution volume and changes on each day, and postoperative complications and wound healing time were recorded. After discharge, the wound healing quality, thorax shape, and mobility functions of thorax and both upper limbs were evaluated during follow-up. The stability and closure of sternum were observed by computed tomography (CT) reexamination. Results: On admission, among 36 patients, 33 cases were positive and 3 cases were negative in bacterial culture results of wound exudation specimens. Intraoperative observation showed that 26 patients had no retrosternal mediastinal infection but had fresh granulation tissue in unhealed sternal wounds, palliative debridement was performed and bilateral pectoralis major muscles were advanced and abutted to cover the defect. In 10 patients with suspected retrosternal mediastinal abscess cavity, the local sternum was completely removed by bite and the defect was covered using flipped unilateral pectoralis major muscle. During the operation, one patient experienced an innominate vein rupture and bleeding of approximately 3 000 mL during mediastinal exploration, and the remaining patients experienced bleeding of 100-1 000 mL. Postoperative infusion and lavage were performed for 4-7 days, with a lavage solution volume of 3 500-4 500 mL/d. The lavage solution gradually changed from dark red to light red and finally clear. Except for 1 patient who had suture rupture caused by lifting the patient under the armpit during nursing on the 3rd day after surgery, the wounds of the other patients healed smoothly after surgery, and the wound healing time of all patients was 7-21 days. Follow-up for 3 to 9 months after discharge showed that the patient who had suture rupture caused by armpit lifting died due to multiple organ failure. In 1 patient, the armor-like chest strap was removed 2 weeks after surgery, and the shoulder joint movement was not restricted, resulting in local rupture of the suture, which healed after dressing change. The wounds of the remaining patients healed well, and they resumed their daily life. The local skin of patient's pectoralis major muscle defect was slightly sunken and lower than that of the contralateral thorax in the patients undergoing treatment of pectoralis major muscle inversion, while no obvious thoracic deformity was observed in patients undergoing treatment with pectoralis major muscle propulsion and abutment. The chest and upper limb movement in all patients were slightly limited or normal. CT reexamination results of 10 patients showed that the sternum was stable, the local sternum was closed or covered completely with no lacuna or defects. Conclusions: Once the wound associated with secondary sternal osteomyelitis and/or mediastinitis after sternotomy is formed, individualized and precise debridement should be performed as soon as possible, different transfer ways of pectoralis major muscle flap should be chosen to cover the defect, and postoperative continuous infusion and lavage together with strict thorax and shoulder joint restraint and immobilization should be performed. This treatment strategy can ensure good wound healing without affecting the shape and function of the donor area.

Surgical treatment of nasopharyngeal cancer - a consensus recommendation from two Chinese associations

BACKGROUND

Surgical treatment is playing an increasingly important role in the management of nasopharyngeal carcinoma (NPC). This consensus focuses on the indications for optimal surgery, and surgical methods in the whole process of treatment for NPC to provide a useful reference to assist these difficult clinical decisions.

METHODOLOGY

A thorough review of available literature on NPC and surgery was conducted by the Association for the prevention and treatment of nasopharyngeal carcinoma in China, international exchange and promotion Association for medicine and healthcare, and the Committee on nasopharyngeal cancer of Guangdong provincial anticancer association. A set of questions and a preliminary draft guideline was circulated to a panel of 1096 experienced specialists on this disease for voting on controversial areas and comments. A refined second proposal, based on a summary of the initial voting and different opinions expressed, was recirculated to the experts in two authoritative medical science and technology academic groups in the prevention and treatment of NPC in China for review and reconsideration.

RESULTS

The initial round of questions showed variations in clinical practice even among similar specialists, reflecting the lack of high-quality supporting data and resulting difficulties in formulating clinical decisions. Through exchange of comments and iterative revisions, recommendations with high-to-moderate agreement were formulated on general treatment strategies and details of surgery, including indications and surgical approaches.

CONCLUSION

By standardizing the surgical indications and practice, we hope not only to improve the surgical outcomes, but also to highlight the key directions of future clinical research in the surgical management of NPC.

High-Strength Smart Microneedles with "Offensive and Defensive" Effects for Intervertebral Disc Repair

Intervertebral disc degeneration (IVDD) is a global public health issue. The injury of annulus fibrosus (AF) caused by acupuncture or discectomy can trigger IVDD again. However, there is currently no suitable method for treating AF injury. In this study, the high-strength smart microneedles (MNs) which can penetrate the AF tissue through a local and minimally invasive method, and achieve remote control of speeded-up release of the drug and hyperthermia by the Near Infrared is developed. The PDA/GelMA composite MNs loaded with diclofenac sodium are designed to extracellularly "offend" the inflammatory microenvironment and mitigate damage to cells, and intracellularly increase the level of cytoprotective heat shock proteins to enhance the defense against the hostile microenvironment, achieving "offensive and defensive" effects. In vitro experiments demonstrate that the synergistic treatment of photothermal therapy and anti-inflammation effectively reduces inflammation, inhibits cell apoptosis, and promotes the synthesis of the extracellular matrix (ECM). In vivo experiments show that the MNs mitigate the inflammatory response, promote ECM deposition, reduce the level of apoptosis, and restore the biomechanical properties of the intervertebral disc (IVD) in rats. Overall, this high-strength smart MNs display promising "offensive and defensive" effects that can provide a new strategy for IVD repair.

[Attention should be paid to sleep disorders in critically ill patients and its recognition and intervention]

The sleep deficiency and sleep disturbance of critically ill patients may result in adverse outcomes, negative effects on early rehabilitation, and may persist well beyond the intensive care unit (ICU). It has been paid more and more attention in clinical practice. The sleep problems of critically ill patients are associated with suffered critical illness, ICU environments, and coexisting sleep disorders before critical illness. Poor sleep quality, insufficient sleep duration, severe sleep fragmentation and irregular circadian rhythms during critical care illness have been extensively described. In addition, ICU patients have been specifically shown to experience atypical sleep and pathologic wakefulness. So the sleep in critical ill patients should be evaluated. Sleep can be evaluated by both subjective assessment and objective measurements, including polysomnography and actigraphy. According to individual situation, comprehensive, interdisciplinary, and personalized interventions, which include treating critical illness, improving ICU environment to reduce interference to sleep, nonpharmacological treatment to relax and stabilize sleep, and treating coexisting sleep disorders, should be taken to improve the patient's sleep and then to promote the early rehabilitation of critically ill patients.

[Analysis of dynamic functional connectivity states and influencing factors of brain network in male patients with obstructive sleep apnea]

Objective: To analyze dynamic functional connectivity (dFNC) states and influencing factors of brain network in male patients with obstructive sleep apnea (OSA). Methods: A total of 111 male patients diagnosed with obstructive sleep apnea or presenting with simple snoring, who visited the Sleep Clinic at the Second Affiliated Hospital of Soochow University between August 2020 and December 2021, were prospectively selected for this study. General information was collected, and polysomnography (PSG) was performed. Based on the oxygen desaturation index (ODI), the participants were divided into three groups: primary snoring group (ODI<5 events/hour, n=34), mild to moderate OSA group (5 events/hour≤ODI<30 events/hour, n=43), and sever OSA group (ODI≥30 events/hour, n=34). Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) scale, and daytime sleepiness was evaluated using the Epworth Sleepiness Scale (ESS). Resting-state functional magnetic resonance imaging (fMRI) data were collected and preprocessed. dFNC matrices were constructed using a sliding time window approach. The number of dFNC states was determined using k-means clustering analysis. Three parameters, namely, fractional time (FT), mean dwell time (MDT), and number of transitions (NT), were used to characterize the temporal properties of dFNC states. Differences in the temporal properties of dFNC states among the groups were compared. The correlations between temporal properties and PSG parameters, as well as MoCA and ESS scores, were further analyzed. Multiple stepwise linear regression analysis was performed to identify the influencing factors of the temporal properties of dFNC states. Results: The age of the patients was (40.2±8.6) years (range: 25-65 years). There were no significant differences in age, smoking history and alcohol history, and MoCA scores among the three groups (all P>0.05). Three dFNC states were extracted through k-means clustering analysis: state 1, characterized by strong connections within the visual and sensorimotor networks with a frequency of 31.7% (4 611/14 541); state 2, characterized by strong connections within the default mode network, attention network, and other cognitive networks, with the lowest frequency of 22.1% (3 213/14 541); state 3, characterized by weaker connections across the whole brain, with the highest frequency of 46.2% (6 717/14 541). The FT [0.28 (0.05, 0.35) vs 0.39 (0.26, 0.53)] and MDT [8.20 (4.35, 12.54) vs 11.68 (8.50, 16.69)] of state 2 in the sever OSA group were lower than those in the primary snoring group (both P<0.05), while there were no significant differences in the temporal properties of states 1 and 3 among the three groups (all P>0.05). The FT and MDT of state 2 were correlated with body mass index (BMI), apnea-hypopnea index (AHI), ODI, and minimum oxygen saturation (MinSaO2) (FT: r values were -0.218, -0.230, -0.249, 0.198, respectively; MDT: r values were 0.269, -0.253, -0.265, 0.209, respectively; all P<0.05). There were no significant correlations between the temporal properties and MoCA or ESS scores (all P>0.05). ODI was found to be an influencing factor for the temporal properties of state 2 (FT: β=-0.225, 95%CI:-0.227 to -0.223; MDT: β=-0.241, 95%CI:-0.289 to -0.195). Conclusions: Male patients with OSA exhibit alterations in specific temporal properties of brain network dynamic functional connectivity, which are associated with nocturnal oxygen parameters. This may be one of the mechanisms underlying brain functional damage in patients with OSA.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm

We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{μ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{μ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{μ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision.

Silk Fibroin/Wool Keratin Composite Scaffold with Hierarchical Fibrous and Porous Structure

The present study describes a silk microfiber reinforced meniscus scaffold (SMRMS) with hierarchical fibrous and porous structure made from silk fibroin (SF) and wool keratin (WK) using electrospinning and freeze-drying technology. This study focuses on the morphology, secondary structure, mechanical properties, and water absorption properties of the scaffold. The cytotoxicity and biocompatibility of SMRMS are assessed in vivo and in vitro. The scaffold shows hierarchical fibrous and porous structure, hierarchical pore size distribution (ranges from 50 to 650 µm), robust mechanical properties (compression strength can reach at 2.8 MPa), and stable biodegradability. A positive growth condition revealed by in vitro cytotoxicity testing indicates that the scaffold is not hazardous to cells. In vivo assessments of biocompatibility reveal that only a mild inflammatory reaction is present in implanted rat tissue. Meniscal scaffold made of SF/WK composite shows a potential application prospect in the meniscal repair engineering field with its development.

The Lyman Normal Tissue Complication Probability Model and Risk Prediction for Temporal Lobe Injury after Re-Irradiation in Patients with Recurrent Nasopharyngeal Carcinoma

PURPOSE/OBJECTIVE(S)

The risk of temporal lobe injury (TLI) in recurrent nasopharyngeal carcinoma (rNPC) patients with intensity-modulated radiation therapy (IMRT) is high. We aimed to construct the normal tissue complication probability (NTCP) model for TLI of rNPC and establish a risk predictive model.

MATERIALS/METHODS

We retrospectively analyzed 103 patients with rNPC who had received two courses of IMRT in our institution. The 206 temporal lobes (TLs) of these patients were randomly divided into a training (n = 144) and validation group (n = 62). We determined the mean value of the following parameters to construct the Lyman NTCP model: TD50(1) (the dose with a 50% probability of complications to an organ when all volumes are irradiated), m [steepness of the dose-response at TD50(1)], and n (the parameter related to volume effect). The most predictive dosimetric parameter and clinical variables were integrated in Cox proportional hazards models. A nomogram was developed for predicting risk of TLs.

RESULTS

The parameters of the fitted NTCP model were TD50(1) = 107.84 Gy (95% confidence interval (CI), [97.15, 118.54]), m = 0.16 (95% CI, [0.14, 0.19]), and n = 0.04 (95% CI, [0.01, 0.06]). The cumulative dose delivered to 0.1 cm3 of temporal lobe volume (D0.1cc-c) was the most predictive dosimetric parameter for TLI. The Kaplan-Meier curves showed a significant difference in 2-year TLI-free survival among different risk groups according to the total score of nomograms.

CONCLUSION

The TD50(1) of TLI in patients with rNPC is 107.84 Gy in Lyman NTCP model. The nomogram model can accurately predict the risk of TLI for individual.

Effect of Segmental Abutting Esophagus-Sparing Technique to Reduce Severe Esophagitis in Limited-Stage Small-Cell Lung Cancer Patients Treated with Concurrent Hypofractionated Thoracic Radiation and Chemotherapy

PURPOSE/OBJECTIVE(S)

To evaluate the effect of segmental abutting esophagus-sparing (SAES) radiotherapy to reduce severe (G3+) acute esophagitis from 20% to 5% in patients with limited-stage small cell lung cancer (LS-SCLC) treated with concurrent chemoradiotherapy.

MATERIALS/METHODS

Patients with a clinical target volume (CTV) ≤1 cm close to the esophagus were enrolled in the experimental arm (45 Gy in 3 Gy daily fractions in 3 weeks) of an ongoing phase III randomized clinical trial (NCT02675088), which enrolled patients with histologically confirmed SCLC and clinically staged as LS or I-IIIB (AJCC 7th). This trial was designed to determine whether HYPO TRT (45 Gy in 3 Gy QD, experimental arm) has the same efficacy as CF TRT (60 Gy in 2 Gy QD, controlled arm) in patients with LS-SCLC. The whole esophagus was divided into the involved esophagus and abutting esophagus (AE) to receive different dose limitations according to the distance from the edge of the CTV. The primary endpoint was grade ≥ 3 acute esophagitis.

RESULTS

From 1 May 2021 to 30 April 2022, 30 patients were enrolled and completed four cycles of planned chemotherapy and radiotherapy. Our patient population was predominantly male (66.7% men vs. 33.3% women), with a median age of 62 years. A majority of patients presented with Stage N2-3 (90.0%) and T2-4 (76.7%), in which 4 patients had ultracentral-located primary tumors. With the SAES technique, all dosimetric parameters were significantly reduced for the whole esophagus and AE. The maximal and mean dose of the esophagus (47.4±1.9 Gy and 13.5 ± 5.8 Gy, respectively) and AE (42.9±2.3 Gy and 8.6 ± 3.6 Gy, respectively) in the SAES plan were significantly lower than those (esophagus 48.0±1.9 Gy and 14.7± 6.1 Gy, AE 45.1±2.4 Gy and 9.8± 4.2 Gy, respectively) in the non-SAES plan. After the follow-up of more than 7 months (range, 7.0-18.1 months) for all patients, only one patient (3.3%, 95% CI 0.1%-17.2%) experienced grade 3 acute esophagitis and no grade 4-5 acute esophagitis happened (Table 3). For late toxicities, one patient suffered sustained grade 1 late esophagitis and all others had no symptoms of esophagitis. The rate of radiation pneumonitis was very low, with one grade 3 event and no grade 4-5 event. Twelve (40.0%) patients had G3+ hematologic toxic events, including 2 patients with febrile neutropenia. The 1-year OS, LRFS, DMFS and PFS was 96.4%, 88.7%, 78.4% and 64.3%, respectively. No patient developed local recurrence in the abutting esophagus-sparing region.

CONCLUSION

SAES radiotherapy has significant dosimetric advantages compared with standard radiotherapy, which are successfully translated into clinical benefits for patients with LS-SCLC treated with 45 Gy in 3 Gy daily fractions. This may facilitate dose escalation for TRT in LS-SCLC patients.

Radiation-Induced Nasopharyngeal Necrosis in Locally-Recurrent Nasopharyngeal Carcinoma Patients after Re-Radiotherapy

PURPOSE/OBJECTIVE(S)

Re-radiotherapy (re-RT) is the main treatment for locally recurrent nasopharyngeal carcinoma (lrNPC) patients, and commonly led to radiation-induced nasopharyngeal (NP) necrosis, which was lethal but rare study has focused on it. The aim of this study was to evaluate the cause and impact of radiation-induced NP necrosis in lrNPC patients who received re-RT.

MATERIALS/METHODS

Totally 252 lrNPC patients who received re-RT between January 2013 and December 2020 were retrospectively collected. The inclusion criteria were as follows: (1) no NP necrosis before re-RT; (2) complete medical records, including treatment, clinical and dosimetric information; (3) conventional fractionated radiotherapy. All patients received intensity-modulated radiotherapy ± chemotherapy. Radiation-induced NP necrosis was diagnosed by magnetic resonance imaging and/or electronic nasopharyngoscopy. Dosimetric factors of the planning target volume of primary tumor (PTVp) were extracted from the dose-volume histogram (DVH), which was rescaled to an equivalent dose of 2 Gy per fraction (EQD 2 Gy) using a linear quadratic model. Logistic regression was used to identify the independent prognostic factors for generating the nomogram.

RESULTS

With a median follow-up of 44.63 months (inter-quartile range [IQR], 27.70 - 69.20 months), 47.6% of patients (120/252) occurred radiation-induced NP necrosis, which mostly happened within 1 year post re-RT (median [IQR], 5.83 [3.37 - 11.57] months). The 3-year overall survival was 83.0% vs 39.7% (P<0.001) in lrNPC patients with or without radiation-induced NP necrosis. Except for the fractionated dose, other dosimetric factors of PTVp were not significantly different between two groups, including D98 (dose to 98% of PTVp), D50, D2 and homogeneity index (Table 1). Furthermore, multivariate analysis showed that continuous variable age (HR [95% CI]: 1.04 [1.02 - 1.07], P = 0.003) and tumor volume (HR [95% CI]: 1.02 [1.01 - 1.03], P<0.001), and fractionated dose > 2.22 Gy (HR [95% CI]: 2.36 [1.32 - 4.21], P = 0.004) were independent factors in predicting radiation-induced NP necrosis, which yielded a C-index of 0.742 (95% CI, 0.682 - 0.803) for OS in the nomogram.

CONCLUSION

The incidence of radiation-induced NP necrosis was high in lrNPC patients who received re-RT. Patients with older age, larger tumor volume or receiving fractionated dose over 2.22 Gy were more easily to suffer NP necrosis, which need to explore novel treatment strategies to improve patients' survivals.

[Relationships between hypertensive disorders in pregnancy and obstructive sleep apnea syndrome]

Objective: To investigate the impact of obstructive sleep apnea syndrome (OSAS) on pregnancy outcomes, especially the relationship between OSAS and hypertensive disorders in pregnancy (HDP). Methods: A total of 228 pregnant women with high risk of OSAS who underwent sleep monitoring during pregnancy in Peking University People's Hospital from January 2021 to April 2022 were collected by reviewing their medical records for retrospective analysis. According to the diagnosis of OSAS, the pregnant women were divided into OSAS group (105 cases) and non-OSAS group (123 cases). The non-parametric Mann-Whitney U test, χ2 test or Fisher's exact test were used to compare the general data and maternal and fetal outcomes between the two groups, and the occurrence of each type of HDP was further compared. Results: (1) Compared with the non-OSAS group, the median pre-pregnancy body mass index (23.6 vs 27.6 kg/m2) and the proportion of snoring [28.9% (33/114) vs 59.2% (61/103)] in the OSAS group were higher, and the differences were both statistically significant (both P<0.001). (2) The incidence of HDP [67.6% (71/105) vs 39.0% (48/123)] and gestational diabetes mellitus [GDM; 40.0% (42/105) vs 26.8% (33/123)] of pregnant women in the OSAS group were higher than those in the non-OSAS group, and the median delivery week was shorter than that in the non-OSAS group (38.4 vs 39.0 weeks). The differences were all statistically significant (all P<0.05). Between-group differences for the delivery way, postpartum hemorrhage, the rate of intensive care unit admission, preterm birth, small for gestational age infants, neonatal asphyxia, the rate of neonatal intensive care unit admission, newborn birth weight and the proportion of umbilical artery blood pH<7.00 were not statistically significant (all P>0.05). (3) Compared with the non-OSAS group, the incidence of chronic hypertension [11.4% (14/123) vs 22.9% (24/105)] and chronic hypertension with superimposed pre-eclampsia [11.4% (14/123) vs 30.5% (32/105)] were higher in the OSAS group, and the differences were both statistically significant (both P<0.01). Conclusion: OSAS is related to HDP (especially chronic hypertension and chronic hypertension with superimposed pre-eclampsia) and GDM, which could provide a practical basis for the screening, diagnosis and treatment of OSAS in pregnant women at high risk.

[Curative effects of medial plantar free flap in reconstructing electric burn wound and scar contracture in the palm]

Objective: To explore the curative effects of medial plantar free flap in reconstructing electric burn wound and scar contracture in the palm. Methods: A retrospective observational study was conducted. From January 2020 to January 2023, 6 patients with electric burn wounds or scar contracture in the palm who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University, including 5 males and 1 female, aged 35 to 55 years. The wound area was 5.0 cm×3.0 cm-8.0 cm×7.0 cm after the debridement of electric burn wounds or resection of scar in the palm. The medial plantar free flap anastomosed with cutaneous nerve was used for wound reconstruction, with flap area of 5.5 cm×3.5 cm-8.5 cm×7.5 cm. The wound in the donor site was repaired with transplantation of abdominal full-thickness skin graft. After surgery, the survival of flaps and skin grafts were observed, the shape and texture of flap and the recovery of donor site of flap were observed, and the holding function of the affected hand was assessed. At the last follow-up, the two-point discrimination distance of flap was measured, the sensory recovery of flap was evaluated with the trial standard for the evaluation of the functions of the upper limbs of the Hand Surgery Society of the Chinese Medical Association, and the function recovery of flap was evaluated by post-surgery flap function evaluation scale. Results: After surgery, 5 flaps survived well, while the distal part of 1 flap was partially necrotic, which was repaired by medium-thickness skin graft from lateral thigh after debridement. All the skin grafts at the donor sites survived well. During follow-up of 3 to 24 months, the flap was not bloated, the texture and color were good, the match with the surrounding tissue was high, with no obvious scar contracture occurred at the donor site. The affected hand had good holding function. At the last follow-up, the two-point discrimination distance of flap was 6-8 mm, the flap sensation recovery was as follows: 5 flaps recovered to grade S3+, 1 flap recovered to grade S3, and the functional evaluation of flaps was excellent in 5 cases and good in 1 case. The patients basically returned to normal life and work. Conclusions: The medial plantar free flap with cutaneous nerve anastomosis has many advantages, such as high matching degree of appearance, good sensory recovery, and holding function of the affected hand. It is an ideal choice for the reconstruction of the electric burn wound and scar contracture in the palm.

Engineered biomimetic micro/nano-materials for tissue regeneration

The incidence of tissue and organ damage caused by various diseases is increasing worldwide. Tissue engineering is a promising strategy of tackling this problem because of its potential to regenerate or replace damaged tissues and organs. The biochemical and biophysical cues of biomaterials can stimulate and induce biological activities such as cell adhesion, proliferation and differentiation, and ultimately achieve tissue repair and regeneration. Micro/nano materials are a special type of biomaterial that can mimic the microstructure of tissues on a microscopic scale due to its precise construction, further providing scaffolds with specific three-dimensional structures to guide the activities of cells. The study and application of biomimetic micro/nano-materials have greatly promoted the development of tissue engineering. This review aims to provide an overview of the different types of micro/nanomaterials, their preparation methods and their application in tissue regeneration.

Three-dimensional biofabrication of nanosecond laser micromachined nanofibre meshes for tissue engineered scaffolds

There is a high demand for bespoke grafts to replace damaged or malformed bone and cartilage tissue. Three-dimensional (3D) printing offers a method of fabricating complex anatomical features of clinically relevant sizes. However, the construction of a scaffold to replicate the complex hierarchical structure of natural tissues remains challenging. This paper reports a novel biofabrication method that is capable of creating intricately designed structures of anatomically relevant dimensions. The beneficial properties of the electrospun fibre meshes can finally be realised in 3D rather than the current promising breakthroughs in two-dimensional (2D). The 3D model was created from commercially available computer-aided design software packages in order to slice the model down into many layers of slices, which were arrayed. These 2D slices with each layer of a defined pattern were laser cut, and then successfully assembled with varying thicknesses of 100 μm or 200 μm. It is demonstrated in this study that this new biofabrication technique can be used to reproduce very complex computer-aided design models into hierarchical constructs with micro and nano resolutions, where the clinically relevant sizes ranging from a simple cube of 20 mm dimension, to a more complex, 50 mm-tall human ears were created. In-vitro cell-contact studies were also carried out to investigate the biocompatibility of this hierarchal structure. The cell viability on a micromachined electrospun polylactic-co-glycolic acid fibre mesh slice, where a range of hole diameters from 200 μm to 500 μm were laser cut in an array where cell confluence values of at least 85% were found at three weeks. Cells were also seeded onto a simpler stacked construct, albeit made with micromachined poly fibre mesh, where cells can be found to migrate through the stack better with collagen as bioadhesives. This new method for biofabricating hierarchical constructs can be further developed for tissue repair applications such as maxillofacial bone injury or nose/ear cartilage replacement in the future.

[Characteristics of narrow hypopharynx in patients with catathrenia]

Objective: To analyze whether the upper airway of patients with catathrenia has obstructive manifestations using nasal resistance, craniofacial, and upper airway imaging methods, which could benefit the exploration of the etiology and treatment options. Methods: From August 2012 to September 2019, a total of 57 patients with catathrenia in the Department of Orthodontics at Peking University Hospital of Stomatology were included in the study, including 22 males and 35 females, aged (31.1±10.9) years, with a body mass index of (21.7±2.7) kg/m². All the patients were diagnosed by full-night polysomnography at the Sleep Division, Peking University People's Hospital, of which 10 patients were combined with obstructive sleep apnea hypopnea syndrome (OSAHS). The median groaning index of patients was 4.8 (1.8, 13) events/h. Nasal resistance and cone-beam CT were conducted on the patients, and measurements were performed on the craniofacial structures, upper airway, and surrounding soft tissues, compared with non-snoring normal occlusion individuals' references published by the same research team (144 college students recruited at Peking University and 100 non-snoring young adults with normal occlusion recruited at six universities in Beijing). Results: The total nasal resistance of patients with catathrenia was (0.26±0.08) Pa·cm^-3·s^-1. The patients had overall well-developed mandibular hard tissues. However, the patients were found with increased FH/BaN (steep anterior cranial base plane), increased MP/FH (forward rotation of the mandible); increased U1/NA and L1/MP (proclined upper and lower incisors). The sagittal diameter of the velopharynx [(19.2±4.5) mm] was significantly larger than the normal reference (t=8.44, P<0.001), while the sagittal diameter at the hypopharynx [(17.4±6.4) mm] was statistically smaller than the normal reference (t=-2.79, P=0.006). Catarhrenia patients combined with OSAHS presented longer soft palate, tongue, and lower hyoid bone than those with primary catathrenia. Conclusions: In patients with catathrenia, the overall craniofacial characteristics are well-developed skeletal structures, lower nasal resistance, proclined upper and lower incisors, wide upper sagittal development of the upper airway and but narrow hypopharynx. Groaning sounds might be related to the narrowing of the hypopharynx during sleep.

[Alertness and task processing speed impairment status and influencing factors of young-middle aged men with obstructive sleep apnea hypopnea syndrome]

Objective: To investigate the alertness and task processing speed impairment status in young-mild aged men with obstructive sleep apnea hypopnea syndrome (OSAHS), and analyze its influencing factors. Methods: This prospective study recruited 251 snoring patients aged 18 to 59 (38.9±7.6) years in the Sleep Center of the Second Affiliated Hospital of Soochow University from July 2020 to September 2021 and all patients were diagnosed by polysomnography (PSG). Clinical information, Epworth Sleepiness Scale (ESS) and PSG date were collected. All patients were assessed with the Montreal Cognitive Assessment (MoCA) questionnaires, Mini-mental State Examination (MMSE) and Computerized Neurocognitive Assessment System which includes the reaction time of Motor Screening Task (MOT) for alertness, the reaction time of pattern recognition memory (PRM), spatial span (SSP) and spatial working memory (SWM) for task processing speed. Based on AHI tertiles, all patients were divided into Q1 group (AHI<15 times/h, n=79), Q2 group (15 times/h≤AHI<45 times/h, n=88), and Q3 group (AHI≥45 times/h, n=84). The characteristics of clinical information, ESS, PSG parameters and cognitive scores among three groups were compared. Multiple linear stepwise regression was conducted to analyze the influencing factors of cognitive impairment. Results: There were no statistically significant differences in age, years of education, history of smoking and drinking, and past disease history (except for the prevalence of hypertension) among the 3 groups (P>0.05). There were statistically significant among-group differences in the body mass index (BMI), ESS, prevalence of hypertension and complaints of daytime sleepiness (P<0.05). Compared with Q1 and Q2 group, the arousal index (ArI), oxygen desaturation index (ODI),the proportion of non-rapid eye movement phase 1 and 2 (N1+N2) and percentage of total sleep time with oxygen saturation level<90% (TS90) of Q3 group were higher (all P<0.05). In the cognitive assessment, there was no statistically significant difference in the MoCA total and individual scores and MMSE scores among the three groups (P>0.05). Compared with the Q1 group, the task processing speed and alertness were worse in Q3 group, as shown by slower PRM immediate and delayed reaction time, SSP reaction time and MOT reaction time (all P<0.05). The total time of SWM in Q2 group was slower than that in Q1 group (P<0.05). Multiple linear stepwise regression showed that years of education (β=-40.182, 95%CI:-69.847--10.517), ODI (β=3.539, 95%CI: 0.600-6.478) were the risk factors of PRM immediate reaction time. Age(β=13.303,95%CI: 2.487-24.119), years of education(β=-32.329, 95%CI:-63.162--1.497), ODI (β=4.515, 95%CI: 1.623-7.407) were the risk factors of PRM delayed reaction time. ODI was the risk factor of SSP reaction time (β=1.258, 95%CI: 0.379-2.137). TS90 was the risk factor of MOT reaction time (β=1.796, 95%CI: 0.664-2.928). Conclusions: The early cognitive impairment in young-mild aged OSAHS patients was manifested in decreased alertness and task processing speed, and intermittent nocturnal hypoxia was its influencing factor in addition to age and years of education.

Transformation of arginine into zero-dimensional nanomaterial endows the material with antibacterial and osteoinductive activity

Implant-associated infection is a major threat affecting the success of orthopedic surgeries. Although various materials scavenge bacteria by generating reactive oxygen species (ROS), the intrinsic inability of ROS to distinguish bacteria from cells notably limits the therapeutic effects. Here, we found that the arginine carbon dots (Arg-CDs) that were transformed from arginine exhibited supreme antibacterial and osteoinductive activity. We further designed the Schiff base bond between Arg-CDs and aldehyde hyaluronic acid/gelatin methacryloyl (HG) hydrogel to release Arg-CDs in response to the acidic bone injury microenvironment. The free Arg-CDs could selectively kill bacteria by generating excessive ROS. Furthermore, the Arg-CD-loaded HG composite hydrogel showed excellent osteoinductive activity through inducing the M2 polarization of macrophages by up-regulating interleukin-10 (Il10) expression. Together, our findings revealed that transformation of the arginine into zero-dimensional Arg-CDs could endow the material with exceptional antibacterial and osteoinductive activity, favoring the regeneration of infectious bone.

[Effect of sleep spindle density on memory function in patients with obstructive sleep apnea hypopnea syndrome]

Objective: To explore the characteristics of sleep spindle density in nonrapid eye movement (NREM) stage 2 (N2) sleep and its effect on memory function in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods: Patients who underwent polysomnography (PSG) examination due to snoring in the Second Affiliated Hospital of Soochow University from January to December 2021 were prospectively collected. A total of 119 male patients, aged 23-60 (37.4±7.3) years, were enrolled finally. According to the apnea hyponea index (AHI), the subjects were divided into a control group (AHI<15 times/h) of 59 cases and an OSAHS group (AHI≥15 times/h) of 60 cases. The basic information, general clinical data and PSG parameters were collected. Memory function scores were evaluated by using logical memory test (LMT), digit ordering test (DOT) and pattern recognition memory (PRM), spatial recognition memory (SRM) and spatial working memory (SWM) in CANTAB test. The number of N2 sleep spindles in leads left central area (C3) and right central area (C4) was counted by hand and the sleep spindle density (SSD) was calculated. The differences in the above indexes and N2 SSD were compared between the two groups. Shapiro-Wilk method, chi-squared test, Spearman correlation analysis and stepwise multivariate logistic regression analysis were used to investigate the influencing factors of memory scores in patients with OSAHS. Results: Compared with the control group, the proportion of the slow-wave sleep, the minimum blood oxygen saturation, the SSD in C3 of NREM2 stage and the SSD in C4 of NREM2 stage were lower in the OSAHS group. The body mass index (BMI), proportion of N2 sleep, oxygen reduction index, percentage of time with oxyhemoglobin saturation below 90% (TS90), maximum duration of apnea and respiratory effort-related arousal(RERA) were higher in the OSAHS group (all P<0.05). Compared with the control group, the immediate LMT score was lower, while the time for immediately completing PRM test, the total time for immediately completing SRM test and the time for delayed completing PRM test were longer in the OSAHS group, suggesting that the immediate logical memory, immediate visual memory, spatial recognition memory and delayed visual memory were worse in the OSAHS group. Stepwise multivariate logistic regression analysis revealed that the number of years of education (OR=0.744, 95%CI 0.565-0.979, P=0.035), maximum duration of apnea (OR=0.946, 95%CI 0.898-0.997, P=0.038) and N2-C3 SSD (OR=0.328, 95%CI 0.207-0.618, P=0.012) and N2-C4 SSD (OR=0.339, 95%CI 0.218-0.527, P=0.017) were independent factors affecting the immediate visual memory. The AHI (OR=1.449, 95%CI 1.057-1.985, P=0.021), N2-C3 SSD (OR=0.377, 95%CI 0.246-0.549, P=0.009), and N2-C4 SSD (OR=0.400, 95%CI 0.267-0.600, P=0.010) were independent factors affecting delayed visual memory. Conclusions: The decrease in SSD is associated with impaired memory function in patients with moderate-severe OSAHS, which is manifested as impairment of immediate visual memory and delayed visual memory. This suggests that changes of sleep spindle wave in N2 may be an electroencephalographic biomarker for assessing cognitive impairment in OSAHS patients.

Targeting Endogenous Reactive Oxygen Species Removal and Regulating Regenerative Microenvironment at Annulus Fibrosus Defects Promote Tissue Repair

The excessive reactive oxygen species (ROS) level, inflammation, and weak tissue regeneration ability after annulus fibrosus (AF) injury constitute an unfavorable microenvironment for AF repair. AF integrity is crucial for preventing disc herniation after discectomy; however, there is no effective way to repair the AF. Herein, a composite hydrogel integrating properties of antioxidant, anti-inflammation, and recruitment of AF cells is developed through adding mesoporous silica nanoparticles modified by ceria and transforming growth factor β3 (TGF-β3) to the hydrogels. The nanoparticle loaded gelatin methacrylate/hyaluronic acid methacrylate composite hydrogels eliminate ROS and induce anti-inflammatory M2 type macrophage polarization. The released TGF-β3 not only plays a role in recruiting AF cells but is also responsible for promoting extracellular matrix secretion. The composite hydrogels can be solidified in situ in the defect area to effectively repair AF in rats. The strategies targeting endogenous ROS removal and improving the regenerative microenvironment by the nanoparticle-loaded composite hydrogels have potential applications in AF repair and intervertebral disc herniation prevention.

[Clinical effects of autologous split-thickness skin grafting for prefabricating urethra combined with scrotal flap in repairing middle urethral defect with penile defect]

Objective: To investigate the clinical effects of autologous split-thickness skin grafting for prefabricating urethra combined with scrotal flap in repairing middle urethral defect with penile defect. Methods: The retrospective observational study was conducted. Eight male patients (aged 14 to 58 years) with middle urethral defect and penile defect caused by various injuries who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University from January 2015 to January 2022. The length of urethral defect was 3 to 5 cm, and the wound area of penile defect after debridement was 5.0 cm×2.5 cm to 7.0 cm×5.5 cm. All the patients underwent autologous split-thickness skin grafting for prefabricating defect urethra in stage Ⅰ, and urethral anastomosis was performed and unilateral scrotal flap was transferred to reconstruct urethra and penis in stage Ⅱ. The area of scrotal flap was 6.0 cm×3.0 cm to 8.0 cm×6.0 cm. The wound in the donor area of skin graft was covered by oil gauze, and the wound of flap donor area was sutured directly. On the 7th day after the operation of stage Ⅱ, the survival of the flap was observed. In 3 weeks after the operation of stage Ⅱ, the urinary flow rate was measured by the urinary flow rate detector (urinary flow rate >15 mL/s was regarded as unobstructed urination), the urinary fistula and erectile function were observed, and the self-made therapeutic satisfaction questionnaire was used to investigate the therapeutic satisfaction degree of patients. During follow-up, the appearance of the flap recipient area was observed, the Vancouver scar scale (VSS) was used to evaluate the scar situation in the donor areas of skin graft and flap, the urinary flow rate was detected as before, the urethral stricture, urinary fistula, and erectile function were observed, and the therapeutic satisfaction degree of patients was investigated. Results: On the 7th day after the operation of stage Ⅱ, the flaps survived completely in 8 patients. In 3 weeks after the operation of stage Ⅱ, the urinary flow rate was 25.3 (18.0, 38.5) mL/s, with unobstructed urination, without urinary fistula and with erectile function, and the score of therapeutic satisfaction degree was 14.3 (14.0, 15.0). During follow-up of 1 to 7 years, the flap recipient area of 8 patients was full in appearance and not swollen, with similar color to the surrounding tissue; the VSS scores of the donor areas of skin graft and flap were 11.5 (10.0, 13.0) and 10.5 (9.3, 12.0), respectively, the urinary flow rate was 24.6 (17.7, 34.1) mL/s, with no urethral stricture, urinary fistula, and erectile dysfunction, and the score of therapeutic satisfaction degree was 13.5 (13.3, 14.8). Conclusions: Autologous split-thickness skin grafting for prefabricating urethra combined with scrotal flap in repairing the urethral and penile defects not only reconstructs the structure of urethra and the shape of penis, but also restores the sensation and erectile function of penis, with few postoperative complications, no obvious scar hyperplasia, and high satisfaction degree of patients, which is worthy of clinical promotion.

Human amniotic membrane graft for refractory macular hole: A single-arm meta-analysis and systematic review

PURPOSE

The treatment of refractory macular holes is controversial, with human amniotic membrane grafts emerging recently as an attractive option. We performed a meta-analysis and systematic review in this paper to assess the results of human amniotic membrane (hAM) in the treatment of refractory macular hole (MH).

METHODS

We searched the Cochrane Database of Systematic Reviews, Web of Science, PubMed, Embase, China National Knowledge Infrastructure databases, VIP database, Wanfang Data Knowledge Service Platform, Sinomed, Chinese Clinical Trial Registry, and Clinical Trials.gov. Studies reporting hAM for the treatment of refractory MH were included. The outcomes are MH closure rate, visual acuity (VA) improvement rate, and graft dislocation/contracture rate.

RESULTS

A total of 8 studies on 103 eyes were included, all of which had undergone failed vitrectomy and internal limiting membrane (ILM) peeling. In all studies, the VA improvement rate was 66% (95%CI: 45 to 84%), the MH closure rate was 94% (95%CI: 84 to 100%) and the hAM graft dislocation/contracture rate was 6% (95%CI: 0 to 15%). In the studies using cryopreserved hAM grafts, the MH closure rate was 99% (95%CI: 94 to 100%) and the hAM graft dislocation/contracture rate was 3% (0%, 10%). The VA improvement rates were 94% (95%CI: 79 to 100%) in the retinal detachment subgroup, 37% (95%CI: 20 to 56%) in the pathologic myopia subgroup, and 62% (95%CI: 14 to 100%) in the idiopathic MH subgroup.

CONCLUSION

Human amniotic membrane in the treatment of refractory MH results in visual improvement. It has a high macular hole closure rate and low dislocation/contracture rate. Cryopreserved hAM grafts might have better outcomes than dehydrated grafts.

Building Osteogenic Microenvironments with a Double-Network Composite Hydrogel for Bone Repair

The critical factor determining the in vivo effect of bone repair materials is the microenvironment, which greatly depends on their abilities to promote vascularization and bone formation. However, implant materials are far from ideal candidates for guiding bone regeneration due to their deficient angiogenic and osteogenic microenvironments. Herein, a double-network composite hydrogel combining vascular endothelial growth factor (VEGF)-mimetic peptide with hydroxyapatite (HA) precursor was developed to build an osteogenic microenvironment for bone repair. The hydrogel was prepared by mixing acrylated β-cyclodextrins and octacalcium phosphate (OCP), an HA precursor, with gelatin solution, followed by ultraviolet photo-crosslinking. To improve the angiogenic potential of the hydrogel, QK, a VEGF-mimicking peptide, was loaded in acrylated β-cyclodextrins. The QK-loaded hydrogel promoted tube formation of human umbilical vein endothelial cells and upregulated the expression of angiogenesis-related genes, such as Flt1 , Kdr , and VEGF , in bone marrow mesenchymal stem cells. Moreover, QK could recruit bone marrow mesenchymal stem cells. Furthermore, OCP in the composite hydrogel could be transformed into HA and release calcium ions facilitating bone regeneration. The double-network composite hydrogel integrated QK and OCP showed obvious osteoinductive activity. The results of animal experiments showed that the composite hydrogel enhanced bone regeneration in skull defects of rats, due to perfect synergistic effects of QK and OCP on vascularized bone regeneration. In summary, improving the angiogenic and osteogenic microenvironments by our double-network composite hydrogel shows promising prospects for bone repair.

Mechanically conditioned cell sheets cultured on thermo-responsive surfaces promote bone regeneration

Cell sheet-based scaffold-free technology holds promise for tissue engineering applications and has been extensively explored during the past decades. However, efficient harvest and handling of cell sheets remain challenging, including insufficient extracellular matrix content and poor mechanical strength. Mechanical loading has been widely used to enhance extracellular matrix production in a variety of cell types. However, currently, there are no effective ways to apply mechanical loading to cell sheets. In this study, we prepared thermo-responsive elastomer substrates by grafting poly(N-isopropyl acrylamide) (PNIPAAm) to poly(dimethylsiloxane) (PDMS) surfaces. The effect of PNIPAAm grafting yields on cell behaviours was investigated to optimize surfaces suitable for cell sheet culturing and harvesting. Subsequently, MC3T3-E1 cells were cultured on the PDMS-g-PNIPAAm substrates under mechanical stimulation by cyclically stretching the substrates. Upon maturation, the cell sheets were harvested by lowering the temperature. We found that the extracellular matrix content and thickness of cell sheet were markedly elevated upon appropriate mechanical conditioning. Reverse transcription quantitative polymerase chain reaction and Western blot analyses further confirmed that the expression of osteogenic-specific genes and major matrix components were up-regulated. After implantation into the critical-sized calvarial defects of mice, the mechanically conditioned cell sheets significantly promoted new bone formation. Findings from this study reveal that thermo-responsive elastomer, together with mechanical conditioning, can potentially be applied to prepare high-quality cell sheets for bone tissue engineering.

TGF-β1-supplemented decellularized annulus fibrosus matrix hydrogels promote annulus fibrosus repair

Annulus fibrosus (AF) repair remains a challenge because of its limited self-healing ability. Endogenous repair strategies combining scaffolds and growth factors show great promise in AF repair. Although the unique and beneficial characteristics of decellularized extracellular matrix (ECM) in tissue repair have been demonstrated, the poor mechanical property of ECM hydrogels largely hinders their applications in tissue regeneration. In the present study, we combined polyethylene glycol diacrylate (PEGDA) and decellularized annulus fibrosus matrix (DAFM) to develop an injectable, photocurable hydrogel for AF repair. We found that the addition of PEGDA markedly improved the mechanical strength of DAFM hydrogels while maintaining their porous structure. Transforming growth factor-β1 (TGF-β1) was further incorporated into PEGDA/DAFM hydrogels, and it could be continuously released from the hydrogel. The in vitro experiments showed that TGF-β1 facilitated the migration of AF cells. Furthermore, PEGDA/DAFM/TGF-β1 hydrogels supported the adhesion, proliferation, and increased ECM production of AF cells. In vivo repair performance of the hydrogels was assessed using a rat AF defect model. The results showed that the implantation of PEGDA/DAFM/TGF-β1 hydrogels effectively sealed the AF defect, prevented nucleus pulposus atrophy, retained disc height, and partially restored the biomechanical properties of disc. In addition, the implanted hydrogel was infiltrated by cells resembling AF cells and well integrated with adjacent AF tissue. In summary, findings from this study indicate that TGF-β1-supplemented DAFM hydrogels hold promise for AF repair.

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Injectable DAFM derived hydrogel with mechanical property matching natural AF and sustained TGF-β1 release was developed.

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DAFM derived hydrogels promote AF cell proliferation, migration and ECM production.

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DAFM derived hydrogels display good integration with host AF tissue.

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DAFM derived hydrogels facilitate AF repair and restore intervertebral disc biomechanics.

High-resolution 3D printing of angle-ply annulus fibrosus scaffolds for intervertebral disc regeneration

Intervertebral disc (IVD) degeneration is one of the leading causes of disability, and current therapies are mainly unsatisfactory. The key pathological feature during IVD degeneration is the dysfunction of annulus fibrosus (AF). Although tissue-engineered AF has shown great promise for IVD regeneration, the design and fabrication of biomimetic AF scaffold remains a challenge due to the complexity of its structure. Nowadays, 3D printing technology has drawn great attention due to its customizable processes and ability to produce complex tissue architecture. However, few existing 3D printing methods can accurately replicate the fine angle-ply architecture of native AF, which is one of the most critical steps for IVD regeneration, due to the limited printing resolution. In this study, we aimed to fabricate high-resolution polycaprolactone (PCL) scaffolds using a newly developed electrohydrodynamic 3D printing (EHDP) technique. The structural advantages of such scaffolds were verified by finite element analysis (FEA). The PCL scaffolds were further assembled into AF construct to replicate the angle-ply architecture of AF. The optimal assembling method was confirmed by FEA and mechanical tests. The in vitro experiments showed that the 3D printed AF scaffolds presented favorable biocompatibility and supported the adhesion and growth of AF cells. The in vivo performance of tissue-engineered IVDs (TE-IVDs), which consisted of 3D printed AF scaffold and GelMA hydrogel that simulated nucleus pulposus (NP), were evaluated using a rat total disc replacement model. We found that the implantation of TE-IVDs helped maintain the disc height, reduced the loss of NP water content, and partially restored the biomechanical function of IVD. In addition, the TE-IVDs achieved well integration with adjacent tissues and promoted new tissue formation. In summary, being able to accurately simulate the structural characteristics of native AF, the 3D printed angle-ply AF scaffolds hold potential for future applications in IVD regeneration.

Multifunctional Nanofibrous Scaffolds with Angle-Ply Microstructure and Co-Delivery Capacity Promote Partial Repair and Total Replacement of Intervertebral Disc

There is an urgent clinical need for the treatment of annulus fibrosus (AF) impairment caused by intervertebral disc (IVD) degeneration or surgical injury. Although repairing injured AF through tissue engineering is promising, the approach is limited by the complicated angle-ply microstructure, inflammatory microenvironment, poor self-repairing ability of AF cells and deficient matrix production. In this study, electrospinning technology is used to construct aligned core-shell nanofibrous scaffolds loaded with transforming growth factor-β3 (TGFβ3) and ibuprofen (IBU), respectively. The results confirm that the rapid IBU release improves the inflammatory microenvironment, while sustained TGFβ3 release enhances nascent extracellular matrix (ECM) formation. Biomaterials for clinical applications must repair local AF defects during herniectomy and enable AF regeneration during disc replacement, so a box defect model and total IVD replacement model in rat tail are constructed. The dual-drug delivering electrospun scaffolds are assembled into angle-ply structure to form a highly biomimetic AF that is implanted into the box defect or used to replace the disc. In two animal models, it is found that biomimetic scaffolds with good anti-inflammatory ability enhance ECM formation and maintain the mechanical properties of IVD. Findings from this study demonstrate that the multifunctional nanofibrous scaffolds provide inspirations for IVD repair.

[A prospective randomized controlled study on the repair of skin and soft tissue defect in functional areas of children with full-thickness skin grafts from different sites of abdomen]

Objective: To compare and analyze the effect of repairing small skin and soft tissue defect wounds in functional areas of children with full-thickness skin grafts from different sites of abdomen. Methods: A prospective randomized controlled study was conducted. From January 2019 to June 2020, 60 female children with small skin and soft tissue defects in functional areas requiring full-thickness skin grafting, who met the inclusion criteria, were admitted to the First Affiliated Hospital of Air Force Medical University. According to the random number table, the children were divided into two groups, with 28 cases left in lateral abdomen group aged 5 (3, 8) years and 29 cases in lower abdomen group aged 5 (3, 7) years after the exclusion of several dropped-out children in follow-up. In lower abdomen group, 20 (12, 26) cm2 wounds of children were repaired with (24±10) cm2 full-thickness skin graft from transverse skin lines in the inferior abdomen area, while in lateral abdomen group, 23 (16, 32) cm2 wounds of children were repaired with (24±9) cm2 full-thickness skin graft from below the umbilical plane to above the groin in the lateral abdomen area. All the children were treated with continuous intradermal suture at the donor site incision and received continuous negative pressure treatment of -10.64 to -6.65 kPa in the donor and recipient areas after operation. The donor site was treated with a medical skin tension-reducing closure device since post-surgery day (PSD) 7. The use of medical skin tension-reducing closure device at the donor site, postoperative complications and suture removal time of the donor area were recorded, and the incidence of complications was calculated. On PSD 7, a self-designed efficacy satisfaction questionnaire was used to investigate the parents' satisfaction with the curative effect of their children. In post-surgery month (PSM) 1 and 6, Vancouver scar scale (VSS) was used to evaluate the scar at the donor site, and the VSS score difference between the two time points was calculated; the scar width at the donor site was measured with a ruler, and the scar width difference between the two time points was calculated. Data were statistically analyzed with independent sample t test or Cochran & Cox approximate t test, Mann-Whitney U test, and Fisher's exact probability test. Results: The proportion of children in lateral abdomen group who used the medical skin tension-reducing closure device in the donor area for equal to or more than 4 weeks after surgery was significantly higher than that in lower abdomen group (P<0.05). On PSD 7, there was one case of partial incision dehiscence in the donor area, one case of peripheral skin redness and swelling in the donor area, and one case of fat liquefaction in the donor area in lateral abdomen group, and one case of partial incision dehiscence in the donor area in lower abdomen group. The incidence of postoperative complications at the donor site of children in lower abdomen group was significantly lower than that in lateral abdomen group (P<0.05). Compared with that in lateral abdomen group, the suture removal time at the donor site of children after surgery in lower abdomen group was significantly shorter (t'=17.23, P<0.01). On PSD 7, the satisfaction score of parents with the curative effect of their children in lower abdomen group was significantly higher than that in lateral abdomen group (t'=20.14, P<0.01). In PSM 1 and 6, the VSS scores of scar at the donor site of children in lower abdomen group were 2.7±0.9 and 2.8±1.0, respectively, which were significantly lower than 7.1±2.2 and 9.1±2.7 in lateral abdomen group (with t values of 10.00 and 11.15, respectively, P<0.01). In PSM 6, the VSS score of scar at the donor site of children in lateral abdomen group was significantly higher than that in PSM 1 (t=3.10, P<0.01), while the VSS score of scar at the donor site of children in lower abdomen group was not significantly higher than that in PSM 1 (P>0.05). The VSS score difference of scar at the donor site of children in lateral abdomen group was significantly greater than that in lower abdomen group (Z=-8.12, P<0.01). In PSM 1 and 6, the scar widths at the donor site of children in lower abdomen group were 2.0 (1.0, 2.0) and 2.0 (2.0, 3.0) mm, respectively, which were significantly narrower than 6.0 (4.0, 10.0) and 8.5 (5.0, 12.0) mm in lateral abdomen group (with Z values of -13.41 and -14.70, respectively, P<0.01). In PSM 6, the scar width at the donor site of children in lateral abdomen group was significantly wider than that in PSM 1 (Z=-2.79, P<0.01), while the scar width at the donor site of children in lower abdomen group was not significantly wider than that in PSM 1 (P>0.05). The difference of scar width at the donor site of children in lateral abdomen group was significantly greater than that in lower abdomen group (Z=-14.93, P<0.01). Conclusions: The use of full-thickness skin grafts from the lower abdomen to repair small skin and soft tissue defect wounds in functional areas of children, especially girls, is effective, simple and easy to operate, and conforms to the principle of aesthetic repair. Compared with transplantation with full-thickness skin graft from the lateral abdomen, lower abdominal full-thickness skin grafting has a low incidence of donor site complications and no obvious scar hyperplasia, which is worthy of clinical promotion.

On boosting the power of Chatterjee’s rank correlation

Chatterjee (2021)’s ingenious approach to estimating a measure of dependence first proposed by Dette et al. (2013) based on simple rank statistics has quickly caught attention. This measure of dependence has the appealing property of being between 0 and 1, and being 0 or 1 if and only if the corresponding pair of random variables is independent or one is a measurable function of the other almost surely. However, more recent studies (Cao & Bickel, 2020; Shi et al., 2022) showed that independence tests based on Chatterjee’s rank correlation are unfortunately rate-inefficient against various local alternatives and they call for variants. We answer this call by proposing an improvement to Chatterjee’s rank correlation that still consistently estimates the same dependence measure but provably achieves near-parametric efficiency in testing against Gaussian rotation alternatives. This is possible by incorporating many right nearest neighbours in constructing the correlation coefficients. We thus overcome the “only one disadvantage” of Chatterjee’s rank correlation (Chatterjee, 2021, Section 7).

The role of microenvironment in stem cell-based regeneration of intervertebral disc

Regenerative medicine for intervertebral disc (IVD) disease, by utilizing chondrocytes, IVD cells, and stem cells, has progressed to clinical trials in the treatment of back pain, and has been studied in various animal models of disc degeneration in the past decade. Stem cells exist in their natural microenvironment, which provides vital dynamic physical and chemical signals for their survival, proliferation and function. Long-term survival, function and fate of mesenchymal stem cells (MSCs) depend on the microenvironment in which they are transplanted. However, the transplanted MSCs and the endogenous disc cells were influenced by the complicated microenvironment in the degenerating disc with the changes of biochemical and biophysical components. It is important to understand how the MSCs and endogenous disc cells survive and thrive in the harsh microenvironment of the degenerative disc. Furthermore, materials containing stem cells and their natural microenvironment have good clinical effects. However, the implantation of tissue engineering IVD (TE-IVD) cannot provide a complete and dynamic microenvironment for MSCs. IVD graft substitutes may need further improvement to provide the best engineered MSC microenvironment. Additionally, the IVD progenitor cells inside the stem cell niches have been regarded as popular graft cells for IVD regeneration. However, it is still unclear whether actual IVD progenitor cells exist in degenerative spinal conditions. Therefore, the purpose of this review is fourfold: to discuss the presence of endogenous stem cells; to review and summarize the effects of the microenvironment in biological characteristics of MSC, especially those from IVD; to explore the feasibility and prospects of IVD graft substitutes and to elaborate state of the art in the use of MSC transplantation for IVD degeneration in vivo as well as their clinical application.

Endothelialized microvessels fabricated by microfluidics facilitate osteogenic differentiation and promote bone repair

In bone tissue engineering, vascularization is one of the critical factors that limit the effect of biomaterials for bone repair. While various approaches have been tried to build vascular networks in bone grafts, lack of endothelialization still constitutes a major technical hurdle. In this study, we have developed a facile technique to fabricate endothelialized biomimetic microvessels (BMVs) from alginate-collagen composite hydrogels within a single step using microfluidic technology. BMVs with different sizes could be readily prepared by adjusting the flow rate of microfluids. All BMVs supported perfusion and outward penetration of substances in the tube. Endothelial cells could adhere and proliferate on the inner wall of tubes. It was also found that the expression of CD31 and secretion of BMP-2 and PDGF-BB were higher in the rat umbilical vein endothelial cells (RUVECs) in BMVs than those cultured on hydrogel. When co-cultured with bone marrow mesenchymal stem cells (BMSCs), endothelialized BMVs promoted the osteogenic differentiation of BMSCs compared to those in acellular BMV group. In vivo, markedly enhanced new bone formation was achieved by endothelialized BMVs in a rat critical-sized calvarial defect model compared to those with non-endothelialized BMVs or without BMVs. Together, findings from both in vitro and in vivo studies have proven that endothelialized BMVs function to facilitate osteogenesis and promote bone regeneration, and therefore might present an effective strategy in bone tissue engineering. STATEMENT OF SIGNIFICANCE: In bone tissue engineering, limited vascularization is one of the critical factors that limit the effect of biomaterials for bone repair. In this study, we developed a facile technique to fabricate endothelialized biomimetic microvessels (BMVs) from alginate-collagen composite hydrogels within a single step using microfluidic technology. Both in vitro and in vivo studies have proven that endothelialized BMVs function to facilitate osteogenesis and promote bone regeneration, and therefore might present an effective strategy in bone tissue engineering.

[The value of OLGA staging system in risk assessment of gastric precancerous states and precancerous lesions]

Objective: To investigate the role of operative link on gastritis assessment (OLGA) staging system in risk assessment of gastric precancerous states and precancerous lesions. Methods: A total of 682 patients undergoing gastroscopy from January to July 2016 at the First Hospital of Jiaxing were enrolled. According to the results of gastroscopy and pathology, patients were divided into five groups by OLGA staging system, respectively. The differences of atrophic progression/reversion rate, detection rates of intraepithelial neoplasia and gastric cancer among different OLGA groups during 5-year follow-up were compared. Results: A total of 437 patients completed endoscopic follow-up, including 207 cases in Stage-0, 158 cases in Stage-Ⅰ, 47 cases in Stage-Ⅱ, 18 cases in Stage-Ⅲ and 7 cases in Stage-Ⅳ. There were 24 cases of atrophy progression, 78 cases of atrophy reversion, 5 cases of intraepithelial neoplasia and 2 cases of gastric cancer. The atrophy progression rate correlated with the rising OLGA stages(χ²=19.14, P<0.001);The rate of atrophy reversion in high-risk group was significantly lower than that in low-risk group(χ²=4.96, P=0.026); The detection rate of intraepithelial neoplasia and gastric cancer in high-risk group was significantly higher than that in low-risk group(χ²=29.63, 11.60, both P<0.05). Conclusions: Histological OLGA staging system is helpful to realize the risk stratification assessment of gastric precancerous states and precancerous lesions. It has practical significance to formulate individualized endoscopic/histological follow-up plan for OLGA high-risk group.

[Clinical characteristics of patients with obstructive sleep apnea hypopnea syndrome combined with alveolar hypoventilation]

Objective: To evaluate the clinical characteristics of patients with obstructive sleep apnea hypopnea syndrome (OSAHS) combined with alveolar hypoventilation. Methods: This retrospective study included patients who were diagnosed as OSAHS by polysomnography (PSG) and underwent daytime awake transcutaneous carbon dioxide (PtcCO₂) monitoring from November 2019 to February 2021 at the Sleep Center of the Second Affiliated Hospital of Soochow University. A total of 177 patients were enrolled in the analysis, including 167 males and 10 females, aged (40±8) years old. Patients with daytime awake PtcCO₂>45 mmHg (1 mmHg=0.133 kPa) were diagnosed as daytime alveolar hypoventilation, with which participants were divided into the daytime alveolar hypoventilation group and non-daytime alveolar hypoventilation group. Body mass index (BMI) cut-off value predicting daytime alveolar hypoventilation was calculated and the patients were divided into the high BMI group and low BMI group. The continuous nocturnal PtcCO₂ data was available for a subset of 128 patients, and the patients were divided into two groups according the daytime alveolar hypoventilation or not. Across-group differences were compared, respectively. Results: Compared with the non-daytime alveolar hypoventilation group (n=125), the BMI [27.57 (26.55, 30.33) vs 26.60 (25.06, 28.09) kg/m²], Epworth sleepiness score(ESS) score [9.50 (6.25, 12.00) vs 7.00 (4.00, 10.75)], higher oxygen desaturation index (ODI) [38.00 (15.23, 64.93) vs 26.80 (11.30, 44.30) events/h] and percentage of total time with oxygen saturation level<90% (TS90%) [11.24% (1.88%, 32.44%) vs 4.35% (0.72%, 9.87%)] of the daytime alveolar hypoventilation group(n=52) were significantly higher (P<0.05), and lowest arterial oxygen saturation (LSaO₂) [74.50% (60.25%, 82.00%) vs 79.00% (73.00%, 84.50%)], mean arterial oxygen saturation (MSaO₂) [94.00% (91.00%, 95.00%) vs 95.00% (94.00%, 96.00%)] were significantly lower (P<0.05). The BMI cut-off value for predicting daytime alveolar hypoventilation was 27.04 kg/m². Of the 177 enrolled patients, 90 were in the high BMI group and 87 were in low group. Compared with the low BMI group, the proportion of daytime sleepiness, the ESS score, the prevalence of hypertension, AHI and daytime awake PtcCO₂ in the high BMI group were significantly higher (P<0.05). Among the subset of 128 patients with nocturnal PtcCO₂ data available, the BMI, daytime PtcCO₂ level, the nocturnal CO₂ level and the prevalence of sleep related alveolar hypoventilation in the daytime alveolar hypoventilation group (n=40) were significantly higher than those in the non-daytime alveolar hypoventilation group (n=88) (P<0.05). Conclusions: The OSAHS patients with alveolar hypoventilation have higher BMI and more severe nocturnal hypoxia. OSAHS patients with BMI>27.04 kg/m² are more likely to develop sleep related alveolar hypoventilation disorder.

[Effect and mechanism of siRNA targeting α-enolase gene combined with paclitaxel on proliferation, invasion and apoptosis of hepatocellular carcinoma cell]

Objective: To investigate the effect of siRNA targeting inhibition of α-enolase (ENO1) combined with paclitaxel on the proliferation, invasion and apoptosis of hepatocellular carcinoma SK-HEP-1 cell and its mechanism. Methods: siRNA-ENO1 (siRNA-ENO1 group) and siRNA-negative control (siRNA-NC group) were transfected into SK-HEP-1 cells in vitro, the untransfected SK-HEP-1 cells were used as the control group, and the transfection effect was detected by real-time fluorescent quantitative polymerase chain reaction and western blotting. After SK-HEP-1 cells were treated with 0, 2.5, 5, 10, 20 and 40 μg/L paclitaxel for 48 hours, the cell survival rate was measured by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) method and the semi inhibitory concentration of paclitaxel was calculated. SK-HEP-1 cells transfected with siRNA-ENO1 or siRNA-NC were treated with 10 μg/L paclitaxel as paclitaxel+ siRNA-ENO1 group and paclitaxel+ siRNA-NC group. The proliferation, clonogenesis, invasion and apoptosis of siRNA-NC group, siRNA-ENO1 group, paclitaxel+ siRNA-ENO1 group and paclitaxel+ siRNA-NC group were detected by MTT, clonogenesis, Transwell chamber and flow cytometry respectively. The expression levels of the phosphorylation of phosphatidylinositol-3-kinase (p-PI3K), p-protein kinase B (Akt) and proliferating cell nuclear antigen (PCNA), matrix metalloproteinase 9 (MMP-9) and B lymphocytoma-2 gene (Bcl-2) were detected by western blotting. Results: Compared with the control group (1.00±0.00 and 0.69±0.04, respectively), the expression levels of ENO1 mRNA and protein (0.25±0.03 and 0.23±0.02, respectively) in siRNA-ENO1 group decreased significantly (P<0.05), but there were no significant differences in the expression levels of ENO1 mRNA and protein in siRNA-NC group (P>0.05). Compared without treatment group [(100.00±0.00)%, P<0.05], the survival rates of SK-HEP-1 cells treated with 2.5, 5, 10, 20 and 40 μg/L paclitaxel [(88.65±6.46)%, (72.36±6.08)%, (60.48±4.23)%, (38.52±3.56)% and (20.75±2.32)%, respectively] decreased significantly (P<0.05), and the semi inhibitory concentration of paclitaxel was 13.26 μg/L. The cell survival rate and clone formation rate of siRNA-ENO1 group [(68.86±5.12)% and (18.12±2.25)%, respectively] were lower than those of siRNA-NC group [(100.00±0.00)% and (29.65±3.06)%, respectively, P<0.05]. The cell survival rate and clone formation rate of the paclitaxel+ siRNA-ENO1 group [(43.28±2.64)% and (8.72±0.52)%, respectively] were significantly different from those of the paclitaxel+ siRNA-NC group [(61.75±5.06)% and (13.48±2.16)%, respectively, P<0.05] and siRNA-ENO1 groups [(68.86±5.12)% and (18.12±2.25)%, respectively, P<0.05]. Cell invasion number in paclitaxel+ siRNA-ENO1 group (23.64±2.12) was lower than that in siRNA-ENO1 group and paclitaxel+ siRNA-NC group (42.16±2.75 and 37.35±2.42, respectively, P<0.05). The apoptosis rates of paclitaxel+ siRNA-NC group and siRNA-ENO1 group [(17.49±1.35)% and (15.29±1.50)%, respectively] were higher than that of siRNA-NC group [(7.21±0.70)%, P<0.05]. The apoptosis rate in the paclitaxel+ siRNA-ENO1 group [(24.59±2.40)%] was higher than those in the paclitaxel+ siRNA-NC group and siRNA-ENO1 group [(17.49±1.35)% and (15.29±1.50)%, respectively, P<0.05]. The expression levels of ENO1, PI3K/Akt signaling pathway related proteins including p-PI3K and p-Akt and the expression levels of PCNA, MMP-9 and Bcl-2 in siRNA-ENO1 group and paclitaxel+ siRNA-NC group were lower than those in siRNA-NC group (P<0.05). The expression levels of ENO1, p-PI3K, p-Akt, PCNA, MMP-9 and Bcl-2 in paclitaxel+ siRNA-ENO1 group were lower than those in siRNA-ENO1 group or paclitaxel+ siRNA-NC group (P<0.05). Conclusion: siRNA targeting inhibition of ENO1 expression can enhance the inhibitory effect of paclitaxel on proliferation, invasion and apoptosis of SK-HEP-1 cells, and its mechanism may be related to the inhibition of PI3K/AKT signaling pathway.

CD271 antibody-functionalized microspheres capable of selective recruitment of reparative endogenous stem cells for in situ bone regeneration

In the strategy of in situ bone regeneration, it used to be difficult to specifically recruit bone marrow mesenchymal stem cells (BM-MSCs) by a single marker. Recently, CD271 has been considered to be one of the most specific markers to isolate BM-MSCs; however, the effectiveness of CD271 antibodies in recruiting BM-MSCs has not been explored yet. In this study, we developed novel CD271 antibody-functionalized chitosan (CS) microspheres with the aid of polydopamine (PDA) coating to recruit endogenous BM-MSCs for in situ bone regeneration. The CS microspheres were sequentially modified with PDA and CD271 antibody through dopamine self-polymerization and bioconjugation, respectively. In vitro studies showed that the CD271 antibody-functionalized microspheres selectively captured significantly more BM-MSCs from a fluorescently labeled heterotypic cell population than non-functionalized controls. In addition, the PDA coating was critical for supporting stable adhesion and proliferation of the captured BM-MSCs. Effective early recruitment of CD271⁺ stem cells by the functionalized microspheres at bone defect site of SD rat was observed by the CD271/DAPI immunofluorescence staining, which led to significantly enhanced new bone formation in rat femoral condyle defect over long term. Together, findings from this study have demonstrated, for the first time, that the CD271 antibody-functionalized CS microspheres are promising for in situ bone regeneration.

[Effects of LINC00839 targeting miR-3666 on proliferation, migration and invasion of hepatocellular carcinoma cells]

Objective: To investigate the effects of lncRNA LINC00839 on the proliferation, migration and invasion of hepatocellular carcinoma cells and its mechanism. Methods: Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of LINC00839 and miR-3666 in hepatocellular carcinoma tissues and adjacent tissues. Pearson correlation was used to analyze the correlation between LINC00839 and miR-3666 expression in liver cancer tissues. Hepatocellular carcinoma cells MHCC97H were cultured in vitro and divided into si-NC group, si-LINC00839 group, miR-NC group, miR-3666 group, si-LINC00839+ anti-miR-NC group, and si-LINC00839+ anti-miR-3666 group. Methylthiazoletrazolium (MTT) method and clone formation experiment were used to detect cell proliferation. Transwell array was used to detect the cell migration and invasion. Western blot was used to detect the protein expressions of p21, E-cadherin and MMP-2. The double luciferase reporter gene experiment was used to verify the regulatory relationship between LINC00839 and miR-3666. Results: Compared with adjacent tissues, the expression level of LINC00839 in hepatocellular carcinoma tissues increased (2.82±0.27 vs. 0.96±0.10, P<0.001), but the expression level of miR-3666 decreased (0.23±0.02 vs. 1.01±0.10, P<0.001). The expression levels of LINC00839 and miR-3666 in liver cancer tissue were negatively correlated (r=-0.658, P<0.001). The survival rate of MHCC97H cells in the si-LINC00839 group [(53.91±5.41)% vs. (100.53±10.22)%], the number of clones formed (92.0±8.0 vs. 164.0±14.3), the number of migration (131.0±12.7 vs. 247.0±22.4), the number of invasion (66.0±6.4 vs. 120.0±11.6) and the protein level of MMP-2 (0.20±0.02 vs. 0.67±0.06) were lower than those in the si-NC group (P<0.001). However, the protein levels of p21 (0.76±0.07 vs. 0.25±0.02) and E-cadherin (0.78±0.08 vs. 0.14±0.01) were higher than those in the si-NC group (P<0.001). LINC00839 targeted and negatively regulated the expression of miR-3666. The survival rate of MHCC97-H cells in the miR-3666 group [(47.93±4.86)% vs. (100.11±10.21)%], the number of clone formation (78.0±7.7 vs. 166.0±15.9), the number of migration (117.0±12.1 vs. 250.0±25.0), the number of invasion (57.0±5.7 vs. 121.0±12.3) and the protein level of MMP-2 (0.16±0.01 vs. 0.69±0.07) were lower than those in the miR-NC group (all P<0.001). However, the protein levels of p21 (0.83±0.08 vs. 0.24±0.02) and E-cadherin (0.87±0.09 vs. 0.13±0.01)were higher than those in the miR-NC group (all P<0.001). The survival rate of MHCC97-H cells in the si-LINC00839+ anti-miR-3666 group [(89.94±9.05)% vs. (54.12±5.39)%], the number of clones (143.0±13.8 vs. 94.0±9.4), the number of migration (208.0±19.8 vs. 129.0±12.6), the number of invasion (108.0±10.1 vs. 65.0±6.4) and the protein level of MMP-2 (0.31±0.03 vs 0.66±0.06) were higher than those in the si-LINC00839+ anti-miR-NC group (P<0.001). However, the protein levels of p21 (0.31±0.03 vs. 0.74±0.07) and E-cadherin (0.28±0.03 vs. 0.80±0.08) were lower than those int the si-LINC00839+ anti-miR-NC group (P<0.001). Conclusion: Inhibition of LINC00839 expression may inhibit the proliferation, migration and invasion of hepatocellular carcinoma cells by targeting up-regulation of miR-3666 expression.

[Validation of a contact-free sleep apnea monitor in adults with obstructive sleep apnea]

Objective: To evaluate the diagnostic value of a contact-free sleep apnea monitor in Chinese adults with obstructive sleep apnea (OSA). Methods: One hundred and ninety-eight participants with snoring were recruited between July 2018 and May 2019 in Sleep Center of Peking University People's Hospital, using nocturnal polysomnography (PSG) and contact-free sleep apnea monitor simultaneously. We evaluated the difference between respiratory event index (REI) generated by contact-free sleep apnea monitor and PSG-Apnea-Hypopnea Index (AHI). We calculated the sensitivity and specificity of OSA diagnosis using the contact-free sleep apnea monitor by hypothesis testing for means, Pearson correlation coefficient and Bland-Altman plots. Then, we used the receiver operating characteristic (ROC) curve to find out the best cut-off of OSA diagnosis. Results: PSG-AHI and the REI of contact-free sleep apnea monitor showed no statistically significant difference [15.9 (4.7, 40.2) vs. 16.2 (6.1, 40.0), P=0.381], and they were significantly correlated (r=0.914, P<0.05), with mean difference of -0.06 (95%CI:-18.44, 18.31). The ROC curve showed that if REI ≥5 events/h was used as diagnostic criteria, the sensitivity and specificity of diagnosing OSA were 91.2% and 58.0%, respectively. The sensitivity and specificity of the contact-free sleep apnea monitor REI≥13.3 in diagnosing moderate and severe OSA were 90.1% and 71.1%, respectively. Conclusion: The REI obtained from the contact-free sleep apnea monitor showed a good agreement with the PSG-AHI, and therefore, the contact-free sleep apnea monitor can be used for the screening of patients with moderate and severe OSA.

On the power of Chatterjee’s rank correlation

Chatterjee (2021) introduced a simple new rank correlation coefficient that has attracted much attention recently. The coefficient has the unusual appeal that it not only estimates a population quantity first proposed by Dette et al. (2013) that is zero if and only if the underlying pair of random variables is independent, but also is asymptotically normal under independence. This paper compares Chatterjee’s new correlation coefficient with three established rank correlations that also facilitate consistent tests of independence, namely Hoeffding’s $D$, Blum–Kiefer–Rosenblatt’s $R$, and Bergsma–Dassios–Yanagimoto’s $\tau^*$. We compare the computational efficiency of these rank correlation coefficients in light of recent advances, and investigate their power against local rotation and mixture alternatives. Our main results show that Chatterjee’s coefficient is unfortunately rate-suboptimal compared to $D$, $R$ and $\tau^*$. The situation is more subtle for a related earlier estimator of Dette et al. (2013). These results favour $D$, $R$ and $\tau^*$ over Chatterjee’s new correlation coefficient for the purpose of testing independence.

Calcium phosphate bone cement with enhanced physicochemical properties via in situ formation of an interpenetrating network

Calcium phosphate cement (CPC), which exhibits excellent biocompatibility and bioactivity, is a well-established material for the repair of bone defects. However, its disadvantages such as poor washout resistance and low mechanical strength limit its clinical applications. In this study, CPC with enhanced washout resistance and mechanical properties has been developed by the in situ crosslinking of glycidyl methacrylate modified γ-polyglutamic acid (m-PGA) within the cement matrix, forming an interpenetrating network. Compared with unmodified CPC, the final setting time of the composite cements was shortened and its washout resistance was significantly improved. In addition, the composite cements showed enhanced mechanical strength and degradation properties. An in vitro study demonstrated that the composite cements exhibited good biocompatibility. The in vivo results showed that the composite cements promoted bone formation. These results suggest that the biocompatible, injectable α-tricalcium phosphate (α-TCP)/m-PGA cements may have the potential to be used as bone filling materials for future clinical applications.

[Efficacy of intravascular ultrasound-guided rotational atherectomy combined with cutting balloon for pretreatment of severe coronary artery calcified lesions]

OBJECTIVE

To investigate the efficacy and safety of intravascular ultrasound (IVUS)-guided rotational atherectomy (RA) combined with cutting balloon for pretreatment of severe calcified lesions in the coronary artery before stent placement.

METHODS

A total of 120 patients with severe coronary artery calcifications detected by IVUS that required percutaneous coronary intervention (PCI) were recruited from our hospital between January, 2016 to January, 2019. The patients were randomized into two groups for pretreatment of the lesions with semicompliant balloon (SB group, 60 cases) or RA combined with CB (RA+CB group, 60 cases), and drug-eluting stents were implanted after the procedure. The immediate success rate of PCI, vascular parameters detected by IVUS after PCI, and the rates of residual stenosis < 10% were compared between the two groups. The incidences of intraoperative complications and major adverse cardiac events (MACE) within 24 months after the surgery were also observed in the two groups.

RESULTS

The immediate success rate was significantly higher in RA+CB group than in SB group (P=0.032). After pretreatment and stent placement, the minimum stent lumen diameter (P=0.035), minimum stent lumen cross-sectional area (P=0.029), immediate lumen acquisition, immediate lumen cross-sectional area acquisition and the rate of residual stenosis < 10% were all significantly higher in RA+CB group than in SB group (P < 0.001). The patients in RA+ CB group showed obviously less residual stenosis of lumen cross-sectional area than those in SB group after the surgery (χ²= 7.859, P=0.005). The incidences of intraoperative complications (χ²=5.997, P=0.014) and MACE within 24 months after the operation (χ²=4.285, P=0.038) were significantly lower in RA+CB group than in SB group.

CONCLUSION

For patients with severe coronary artery calcifications eligible for PCI, RA combined with CB angioplasty can significantly improve the success rate of immediate PCI, expand the lumen diameter and cross-sectional area of the stent after PCI, enhance immediate lumen gain, and reduce the incidence of intraoperative complications and MACE after the operation.

[Exploration of standardized sleep medicine fellowship training in Peking University Health Science Center]

Sleep Medicine is a clinical specialty covering the main categories of sleep-wake disorders. The formal training system for sleep medicine has been established in many countries, but not yet in China. The implementation of a pilot sleep medicine fellowship program was elaborated in this article, based on needs assessment of the relevant affiliated hospitals and teaching hospitals of Peking University Health Science Center. It was intended to draw on experiences to build up formal sleep medicine training system in future.

[Feasibility study of telemedicine model for diagnosis and treatment of patients with obstructive sleep apnea hypopnea syndrome in China]

Objective: To explore the feasibility of applying telemedicine model in disease management for patients with obstructive sleep apnea hypopnea syndrome (OSAHS) in China. Methods: A total of 24 patients were enrolled with suspected OSAHS who were admitted to the Sleep Center of Peking University People's Hospital from October 2015 to September 2016. Patients were diagnosed by electronic questionnaire assessment and home sleep apnea monitoring (HSAT) and were treated with remote automatic positive airway pressure (APAP). After 1 week, 1 month and 3 months of treatment, the patients were followed up by video. The follow-up questionnaire was completed by the patients through an independent data management platform. The APAP treatment data and compliance data were obtained through a built-in digital card of the APAP device. Linear regression model was used to explore the factors related to patient compliance. One-way repeated-measure analysis of variance was used to compare the changes of APAP duration and apnea hypopnea index (AHI) among patients at different treatment time points. Paired t-test was used to compare the EPWORTH scale (ESS) scores before and after treatment. Results: A total of 22 patients were diagnosed with OSAHS, including 20 males (90.9%), aged (45.6±10.2) years and AHI before treatment was (46.9±20.4) times/h. A total of 20 OSAHS patients received APAP treatment, and the proportion of patients with good compliance after 1 week, 1 month and 3 months of treatment were 15/19, 10/19 and 8/18, respectively. The severity of sleepiness before treatment affected compliance. Each 1-point increase in ESS score was associated with a 6.16% (95%CI: 3.01%, 9.31%) increase in compliance. Age, body mass index and AHI before treatment had no effect on compliance (all P values>0.05). The AHI of the patients who had been treated for 1 week, 1 month and 3 months were (2.5±2.1), (2.2±1.6) and (1.9±1.0) times/h, respectively. (P=0.195). After 3 months of treatment, the ESS score was (7.0±3.3), lower than that before treatment (10.6±3.1) (P=0.079). Conclusion: Telemedicine mode of diagnosis and treatment of OSAHS patients has good therapeutic effect and patient compliance, which is practical and feasible.

[Utility of the type 3 portable monitor for the diagnosis of sleep disordered breathing in patients with stable heart failure]

Objective: To evaluate the utility of a type 3 portable monitor (PM) at home for the diagnosis of sleep disordered breathing (SDB) in patients with stable congestive heart failure (CHF). Methods: Seventy-six consecutive patients with CHF (61 males, 15 females, mean±standard deviation age (57.0±16.9) years) were enrolled from the sleep center of Peking university People's Hospital during January 2016 to January 2019, and underwent overnight, unattended home sleep apnea testing (HSAT) with a portable monitor followed by an overnight simultaneous polysomnogram (PSG) with in-laboratory portable monitor (in-lab PM) recording within one week. The consistency of apnea hypopnea index (AHI), obstructive sleep apnea index (OAI), central sleep apnea index (CAI) between HSAT and PSG as well as the in-lab PM and PSG were analyzed by Bland-Altman plot; the sensitivity and specificity of PM for the diagnosis of SDB in patients with CHF were evaluated. Results: The number of patients included in the final analysis were 65 in HSAT, 63 in in-lab PM and 65 in PSG. AHI [M(Q₁,Q₃)] was 26.1 (10.9,40.1) events/h by HSAT, 27.9 (11.3,43.2) events/h by in-lab PM, both were not different from AHI 29.0 (10.2,45.0) events/h by PSG (P>0.05). The AHI, OAI and CAI assessed by HSAT correlated significantly with those by PSG (r=0.892, 0.903, 0.831, P<0.05). Bland-Altman analysis of AHI, OAI, CAI by PSG versus HSAT showed a mean difference of 3.1 events/h, 0.8 events/h, 1.2 events/h; limits of consistency were -15.2 to 21.4 events/h, -9.7 to 11.3 events/h, -10.9 to 13.2 events/h, respectively. Based on a threshold of AHI ≥5 events/h, HSAT had 94.6% sensitivity, 75% specificity, compared to PSG. For detecting Cheyne-Stokes respiration (CSR), a sensitivity of 96.4%,a specificity of 97.2% were achieved, compared to PSG. Conclusion: Type 3 PM can be used to diagnose SDB in patients with CHF.

Mechano-regulation of vascular network formation without branches in 3D bioprinted cell-laden hydrogel constructs

Restoration of a wound is a common surgical procedure in clinic. Currently, the skin required for clinical use is taken from the patient's own body. However, it can be difficult to obtain enough skin sources for large-sized wounds and thus surgeons have started using commercial skin substitutes. The current commercial skin, which includes epidermis substitute, dermis substitute, and bilateral skin substitute, has been popularized in clinic. However, the application is limited by the occurrence of ischemia necrosis after transplantation. Recent studies suggest the use of pre-vascularized skin substitutes for wound healing is a promising area in the research field of skin tissue engineering. Pre-vascularization can be induced by changes in cultivation periods, exertion of mechanical stimuli, or coculture with endothelial cells and various factors. However, few methods could control the formation of vascular branches in engineering tissue in a self-assembly way. In this study, we use three-dimensional (3D) printing technology to confirm that a mechanical force can control the growth of blood vessels in the direction of mechanical stimulation with no branches, and that Yes-associated protein activity is involved in the regulatory progress. In vivo experiments verified that the blood vessels successfully function for blood circulation, and maintain the same direction. Results provide a theoretical basis for products of pre-vascularized skin tissues and other organs created by 3D bioprinting.

Bladder muscle regeneration enhanced by sustainable delivery of heparin from bilayer scaffolds carrying stem cells in a rat bladder partial cystectomy model

In bladder tissue engineering, regeneration of muscle is of equal importance to epithelial regeneration. However, as yet there is no effective strategy for promoting bladder muscle regeneration. In this study we aim to promote bladder muscle regeneration by sustainably delivering heparin from a bilayer scaffold carrying stem cells. The bilayer scaffold [heparin-polycaprolactone (PCL)/bladder decellularized matrix (BAM) Hep-PB/PCL] comprises an electrospun layer (Hep-PB electrospun membrane) and a three-dimensional (3D) printed layer (PCL scaffold), fabricated via coaxial-electrospinning and 3D printing, respectively. Heparin was encapsulated into the core of the Hep-PB fibers with a core-shell structure to sustain its release. The morphology of the bilayer scaffold and the microstructure of the electrospun fibers were characterized. The release behavior of heparin from various electrospun membranes was evaluated. The role of Hep-PB in promoting myogenic differentiation of the adipose-derived stem cells (ADSCs) through sustainable release of heparin was also evaluated. After 7 d culture, Hep-PB/PCL scaffolds carrying ADSCs (defined as ASHP) were used for bladder reconstruction in a rat partial cystotomy model. The result shows that the PCL printed scaffold has ordered macropores (∼370 μm), unlike the compact microstructure of electrospun films. The Hep-PB membrane exhibits a sustained release behavior for heparin. This membrane also shows better growth and proliferation of ADSCs than the other membranes. The polymerase chain reaction results show that the expression of smooth muscle cell markers in ADSCs is enhanced by the Hep-PB scaffold. The results of retrograde urethrography and histological staining indicate that the bladder volume in the ASHP group recovers better, and the regenerated bladder muscle bundles are arranged in a more orderly fashion compared with the direct suture and bladder decellularized matrix groups. Therefore, findings from this study show that bladder muscle regeneration could be enhanced by bilayer scaffolds delivering heparin and carrying stem cells, which may provide a new strategy for bladder tissue engineering.

KLF11 protects chondrocytes via inhibiting p38 MAPK signaling pathway

OBJECTIVE

The purpose of this study was to explore the effects of Kruppel like factors 11 (KLF11) on oxidative stress, apoptosis, and endoplasmic reticulum stress (ERS) in osteoarthritis (OA) and its mechanism.

PATIENTS AND METHODS

Human articular cartilage tissue was used to study the correlation between KLF11 and OA. Furthermore, human chondrocytes were used to explore the effects of KLF11 on oxidative stress, apoptosis, and ERS in chondrocytes by overexpressing KLF11 and using the OA inducer IL-1β. The p38MAPK signaling pathway agonist P79350 was used to study the effect of KLF11 on the p38 MAPK signaling pathway.

RESULTS

Articular cartilage tissue in OA patients and IL-1β-induced chondrocytes expressed higher KLF11. Overexpression of KLF11 significantly reduced oxidative stress levels, apoptosis levels, and activity of ERS-related pathways in chondrocytes. Moreover, P79350 attenuated the protective effect of KLF11 on chondrocytes by activating the p38MAPK signaling pathway.

CONCLUSIONS

KLF11 protects against OA by inhibiting oxidative stress, apoptosis, and ERS in chondrocytes by inhibiting p38MAPK signaling pathway.