Delayed Collagen Production without Myofibroblast Formation Contributes to Reduced Scarring in Adult Skin Microwounds

In adult mammals, wound healing predominantly follows a fibrotic pathway, culminating in scar formation. However, cutaneous microwounds generated through fractional photothermolysis, a modality that produces a constellation of microthermal zones, exhibit a markedly different healing trajectory. Our study delineates the cellular attributes of these microthermal zones, underscoring a temporally limited, subclinical inflammatory milieu concomitant with rapid re-epithelialization within 24 hours. This wound closure is facilitated by the activation of genes associated with keratinocyte migration and differentiation. In contrast to macrothermal wounds, which predominantly heal through a robust myofibroblast-mediated collagen deposition, microthermal zones are characterized by absence of wound contraction and feature delayed collagen remodeling, initiating 5-6 weeks after injury. This distinct wound healing is characterized by a rapid re-epithelialization process and a muted inflammatory response, which collectively serve to mitigate excessive myofibroblast activation. Furthermore, we identify an initial reparative phase characterized by a heterogeneous extracellular matrix protein composition, which precedes the delayed collagen remodeling. These findings extend our understanding of cutaneous wound healing and may have significant implications for the optimization of therapeutic strategies aimed at mitigating scar formation.

Assembly of Interfacial Polyelectrolyte Complexation Fibers with Mineralization Gradient for Physiologically-Inspired Ligament Regeneration

Current synthetic grafts for ligament rupture repair often fail to integrate well with the surrounding biological tissue, leading to complications such as graft wear, fatigue, and subsequent re-rupture. To address this medical challenge, this study aims at advancing the development of a biological ligament through the integration of physiologically-inspired principles and tissue engineering strategies. In this study, interfacial polyelectrolyte complexation (IPC) spinning technique, along with a custom-designed collection system, to fabricate a hierarchical scaffold mimicking native ligament structure, is utilized. To emulate the bone-ligament interface and alleviate stress concentration, a hydroxyapatite (HAp) mineral gradient is strategically introduced near both ends of the scaffold to enhance interface integration and diminish the risk of avulsion rupture. Biomimetic viscoelasticity is successfully displayed to provide similar mechanical support to native ligamentous tissue under physiological conditions. By introducing the connective tissue growth factor (CTGF) and conducting mesenchymal stem cells transplantation, the regenerative potential of the synthetic ligament is significantly amplified. This pioneering study offers a multifaceted solution combining biomimetic materials, regenerative therapies, and advanced techniques to potentially transform ligament rupture treatment.

Is Immediate Lymphatic Reconstruction on Breast Cancer Patients Oncologically Safe? A Preliminary Study

Background

In breast cancer patients receiving axillary lymph node dissection (ALND), immediate lymphatic reconstruction (ILR) with lymphovenous anastomosis is an emerging technique for reducing the risk of arm lymphedema. However, the oncologic safety of surgically diverting lymphatic ducts directly into venules in a node-positive axilla is still a concern of inadvertently inducing metastasis of remaining cancer cells. This study aimed to assess the oncologic safety of ILR.

Methods

From January 2020 to January 2022, 95 breast cancer patients received ALND, and 45 of them also received ILR. Patients with recurrent cancer, with follow-up less than 12 months, and with missed data were excluded. Variables were compared between ILR and non-ILR groups, and the outcome of interest was the rate of distant recurrence after follow-up for at least 1 year.

Results

Thirty-four patients in the ILR group and 32 patients in the non-ILR group fulfilled the inclusion criteria for analysis. No statistically significant difference was noted between groups in terms of age, body mass index, type of breast surgery, pathologic cancer staging, histologic type and grade of breast cancer, molecular subtypes, frequency of axillary lymph node metastasis, or adjuvant therapy. For the patients receiving follow-up for at least 1 year, no statistically significant difference was found in terms of distant recurrence rates between ILR and non-ILR groups (P = 0.44).

Conclusion

For breast cancer patients receiving ALND, ILR with lymphovenous anastomosis is oncologically safe, within an average follow-up period of 21 months.

Single-Cell Transcriptomics Reveals Cellular Heterogeneity and Complex Cell-Cell Communication Networks in the Mouse Cornea

Purpose

To generate a single-cell RNA-sequencing (scRNA-seq) map and construct cell-cell communication networks of mouse corneas.

Methods

C57BL/6 mouse corneas were dissociated to single cells and subjected to scRNA-seq. Cell populations were clustered and annotated for bioinformatic analysis using the R package "Seurat." Differential expression patterns were validated and spatially mapped with whole-mount immunofluorescence staining. Global intercellular signaling networks were constructed using CellChat.

Results

Unbiased clustering of scRNA-seq transcriptomes of 14,732 cells from 40 corneas revealed 17 cell clusters of six major cell types: nine epithelial cell, three keratocyte, two corneal endothelial cell, and one each of immune cell, vascular endothelial cell, and fibroblast clusters. The nine epithelial cell subtypes included quiescent limbal stem cells, transit-amplifying cells, and differentiated cells from corneas and two minor conjunctival epithelial clusters. CellChat analysis provided an atlas of the complex intercellular signaling communications among all cell types.

Conclusions

We constructed a complete single-cell transcriptomic map and the complex signaling cross-talk among all cell types of the cornea, which can be used as a foundation atlas for further research on the cornea. This study also deepens the understanding of the cellular heterogeneity and heterotypic cell-cell interaction within corneas.

The effect of immediate lymphatic reconstruction on the post-operative drain output after axillary lymph node dissection for breast cancer: A retrospective comparative study

INTRODUCTION

Axillary lymph node dissection (ALND) for breast cancer has been considered to be associated with a variety of complications, such as excessive postoperative wound drainage, prolonged drain placement, or seroma formation in the short term, or arm lymphedema in the long run. Immediate lymphedema reconstruction (ILR) has been proposed to reduce the occurrence of arm lymphedema by anastomosing the transected arm lymphatics to nearby branches of the axillary vein immediately after ALND. This study aims to demonstrate that ILR can also reduce the postoperative drainage amount.

PATIENTS AND METHODS

Between April 2020 and January 2022, a total of 76 breast cancer patients receiving ALND were reviewed. Forty four of them also received ILR immediately after ALND. The assignment of ILR surgery was non-random, based on patients' willingness and plastic surgeons' availability. The lymphatic vessels in the axillary wound were anastomosed with nearby terminal branches of the axillary vein under surgical microscope. Patients' characteristics, including age, body mass index (BMI), neoadjuvant therapy, type of breast surgery, the occurrence of seroma formation, number of removed lymph nodes, number of positive nodes, and the drainage amount from the operative wounds were compared between ILR and non-ILR groups.

RESULTS

No statistically significant difference was noted between groups in terms of age (56.5 ± 9.8 vs. 60.9 ± 10.7, p = .09), BMI (22.6 ± 3.7 vs. 23.7 ± 3.8, p = .27), type of breast surgery (p = .32), the occurrence of seroma formation (p = 1.0), the likelihood of receiving neoadjuvant therapy (p = .12), number of lymph nodes removed (17.5 ± 7.6 vs. 17.4 ± 8.3, p = .96), or number of positive nodes on final pathology (3.7 ± 5.4 vs. 4.8 ± 8.5, p = .53) except the ILR group had statistically significantly less drainage amount than non-ILR group (39.3 ± 2.6 vs. 48.3 ± 3.7, p = .046).

CONCLUSION

For breast cancer patients receiving ALND, the immediate lymphatic reconstruction can reduce the postoperative drainage amount from the operative wound.

Signalling by senescent melanocytes hyperactivates hair growth

Niche signals maintain stem cells in a prolonged quiescence or transiently activate them for proper regeneration¹. Altering balanced niche signalling can lead to regenerative disorders. Melanocytic skin nevi in human often display excessive hair growth, suggesting hair stem cell hyperactivity. Here, using genetic mouse models of nevi^2,3, we show that dermal clusters of senescent melanocytes drive epithelial hair stem cells to exit quiescence and change their transcriptome and composition, potently enhancing hair renewal. Nevus melanocytes activate a distinct secretome, enriched for signalling factors. Osteopontin, the leading nevus signalling factor, is both necessary and sufficient to induce hair growth. Injection of osteopontin or its genetic overexpression is sufficient to induce robust hair growth in mice, whereas germline and conditional deletions of either osteopontin or CD44, its cognate receptor on epithelial hair cells, rescue enhanced hair growth induced by dermal nevus melanocytes. Osteopontin is overexpressed in human hairy nevi, and it stimulates new growth of human hair follicles. Although broad accumulation of senescent cells, such as upon ageing or genotoxic stress, is detrimental for the regenerative capacity of tissue⁴, we show that signalling by senescent cell clusters can potently enhance the activity of adjacent intact stem cells and stimulate tissue renewal. This finding identifies senescent cells and their secretome as an attractive therapeutic target in regenerative disorders.

Peptide-functionalized double network hydrogel with compressible shape memory effect for intervertebral disc regeneration

As a prominent approach to treat intervertebral disc (IVD) degeneration, disc transplantation still falls short to fully reconstruct and restore the function of native IVD. Here, we introduce an IVD scaffold consists of a cellulose-alginate double network hydrogel-based annulus fibrosus (AF) and a cellulose hydrogel-based nucleus pulposus (NP). This scaffold mimics native IVD structure and controls the delivery of Growth Differentiation Factor-5 (GDF-5), which induces differentiation of endogenous mesenchymal stem cells (MSCs). In addition, this IVD scaffold has modifications on MSC homing peptide and RGD peptide which facilitate the recruitment of MSCs to injured area and enhances their cell adhesion property. The benefits of this double network hydrogel are high compressibility, shape memory effect, and mechanical strength comparable to native IVD. In vivo animal study demonstrates successful reconstruction of injured IVD including both AF and NP. These findings suggest that this double network hydrogel can serve as a promising approach to IVD regeneration with other potential biomedical applications.

Supramolecular hydrogel for programmable delivery of therapeutics to cancer multidrug resistance

Multidrug resistance (MDR) has been considered as a major adversary in oncologic chemotherapy. To simultaneously overcome drug resistance and inhibit tumor growth, it is essential to develop a drug delivery system that can carry and release multiple therapeutic agents with spatiotemporal control. In this study, we developed a hydrogel containing an enzyme-cleavable peptide motif, with a network structure formed by 4-armed polyethylene glycol (PEG) crosslinked by complementary nucleic acid sequences. Hydrogen bond formation between nucleobase pairing allows the hydrogel to be injectable, and the peptide motif grants deliberate control over hydrogel degradation and the responsive drug release. Moreover, MDR-targeted siRNAs are complexed with stearyl-octaarginine (STR-R8), while doxorubicin (Dox) is intercalated with DNA and nanoclay structures in this hydrogel to enhance therapeutic efficacy and overcome MDR. The results show a successful configuration of a hydrogel network with in situ gelation property, injectability, and degradability in the presence of tumor-associated enzyme, MMP-2. The synergistic effect by combining MDR-targeted siRNAs and Dox manifests with the enhanced anti-cancer effect on drug resistant breast cancer cells in both in vitro and in vivo tumor models. We suggest that with the tailor-designed hydrogel system, multidrug resistance in tumor cells can be significantly inhibited by the co-delivery of multiple therapeutics with spatial-temporal control release.

Hedgehog signaling reprograms hair follicle niche fibroblasts to a hyper-activated state

Hair follicle stem cells are regulated by dermal papilla fibroblasts, their principal signaling niche. Overactivation of Hedgehog signaling in the niche dramatically accelerates hair growth and induces follicle multiplication in mice. On single-cell RNA sequencing, dermal papilla fibroblasts increase heterogeneity to include new Wnt5a^high states. Transcriptionally, mutant fibroblasts activate regulatory networks for Gli1, Alx3, Ebf1, Hoxc8, Sox18, and Zfp239. These networks jointly upregulate secreted factors for multiple hair morphogenesis and hair-growth-related pathways. Among these is non-conventional TGF-β ligand Scube3. We show that in normal mouse skin, Scube3 is expressed only in dermal papillae of growing, but not in resting follicles. SCUBE3 protein microinjection is sufficient to induce new hair growth, and pharmacological TGF-β inhibition rescues mutant hair hyper-activation phenotype. Moreover, dermal-papilla-enriched expression of SCUBE3 and its growth-activating effect are partially conserved in human scalp hair follicles. Thus, Hedgehog regulates mesenchymal niche function in the hair follicle via SCUBE3/TGF-β mechanism.

Ultrasound Imaging of Facial Vascular Neural Structures and Relevance to Aesthetic Injections: A Pictorial Essay

The facial and submental regions are supplied by complicated neurovascular networks; therefore, facial aesthetic injections may be associated with serious adverse events such as skin necrosis and blindness. Pre-injection localization of neurovascular structures using high-resolution ultrasound can theoretically prevent unexpected complications. Therefore, a systematic protocol that focuses on these facial neurovascular structures is warranted. In this pictorial essay, we discuss the sonoanatomy of facial and submental neurovascular structures and its relevance to aesthetic injections. Moreover, we have highlighted the mechanisms underlying potential neurovascular injuries during aesthetic injections.

Depilatory laser miniaturizes hair by inducing bystander dermal papilla cell necrosis through thermal diffusion

OBJECTIVES

Depilatory laser targeting melanin has been widely applied for the treatment of hypertrichosis. Both selective photothermolysis and thermal diffusion have been proposed for its effect, but the exact mechanism of permanent hair reduction remains unclear. In this study, we explore the role of thermal diffusion in depilatory laser-induced permanent hair loss and determine whether nonpigmented cells are injured by thermal diffusion.

MATERIALS AND METHODS

C57BL/6 mice in anagen and telogen were treated with alexandrite laser (wavelength 755 nm, pulse duration 3 milliseconds, fluence 12 J/cm² , spot size 12 mm), respectively. Histological analysis, terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, and transmission electron microscopic imaging were employed to evaluate the injury to hair follicle (HF) cells. The proliferation status of HF cells was examined by 5-bromo-2'-deoxyuridine pulse labeling. The number of HF stem cells was quantified by fluorescence-activated cell sorting. The size of the regenerated hair was determined by measuring its length and width.

RESULTS

We found that irradiating C57BL/6 mice in anagen with alexandrite laser led to hair miniaturization in the next anagen. In addition to thermal disruption of melanin-containing cells in the precortex region, we also detected necrosis of the adjacent nonpigmented dermal papilla cells due to thermal diffusion. Dermal papilla cells decreased by 24% after laser injury, while the number of bulge stem cells remained unchanged. When the laser was delivered to telogen HFs where no melanin was present adjacent to the dermal papilla, thermal necrosis and cell reduction were not detected in the dermal papilla and no hair miniaturization was observed.

CONCLUSION

Our results suggest that depilatory laser miniaturizes hair by inducing thermal necrosis of dermal papilla cells due to secondary thermal diffusion from melanin-containing precortex cells in the anagen hair bulbs.

Ultrasound Imaging of the Facial Muscles and Relevance with Botulinum Toxin Injections: A Pictorial Essay and Narrative Review

High-resolution ultrasound is preferred as the first-line imaging modality for evaluation of superficial soft tissues, such as the facial muscles. In contrast to magnetic resonance imaging and computed tomography, which require specifically designated planes (axial, coronal and sagittal) for imaging, the ultrasound transducer can be navigated based on the alignment of facial muscles. Botulinum toxin injections are widely used in facial cosmetic procedures in recent times. Ultrasonography is recognized as a useful tool for pre-procedure localization of target muscles. In this pictorial review, we discuss the detailed sonoanatomy of facial muscles and their clinical relevance, particularly with regard to botulinum toxin injections. Furthermore, we have summarized the findings of clinical studies that report ultrasonographic imaging of facial muscles.

Activating an adaptive immune response from a hydrogel scaffold imparts regenerative wound healing

Microporous annealed particle (MAP) scaffolds are flowable, in situ crosslinked, microporous scaffolds composed of microgel building blocks and were previously shown to accelerate wound healing. To promote more extensive tissue ingrowth before scaffold degradation, we aimed to slow MAP degradation by switching the chirality of the crosslinking peptides from L- to D-amino acids. Unexpectedly, despite showing the predicted slower enzymatic degradation in vitro, D-peptide crosslinked MAP hydrogel (D-MAP) hastened material degradation in vivo and imparted significant tissue regeneration to healed cutaneous wounds, including increased tensile strength and hair neogenesis. MAP scaffolds recruit IL-33 type 2 myeloid cells, which is amplified in the presence of D-peptides. Remarkably, D-MAP elicited significant antigen-specific immunity against the D-chiral peptides, and an intact adaptive immune system was required for the hydrogel-induced skin regeneration. These findings demonstrate that the generation of an adaptive immune response from a biomaterial is sufficient to induce cutaneous regenerative healing despite faster scaffold degradation.

Resuming Oral Feeding in Patients With Oral Squamous Cell Carcinoma With Free Anterolateral Thigh Flap Reconstruction

BACKGROUND

Quality of life and functional improvement have emerged as important goals for patients with oncologic disease. For patients with head and neck cancer, free anterolateral thigh (ALT) flaps serve as reliable reconstruction and provide functional restoration. Nevertheless, factors affecting the resumption of oral feeding are rarely described. This study aimed to evaluate and compare the functional outcomes of oral feeding for patients with different oncologic defect patterns and reconstructive ALT flap designs.

METHODS

We retrospectively reviewed patients with head and neck cancer undergoing oncologic ablation and free ALT reconstruction between January 2016 and April 2018 at National Taiwan University Hospital. Patients were categorized into 2 groups as through-and-through (T&T) and non-through-and-through (non-T&T) according to the defect pattern. We further subgrouped T&T patients into lip resection/lip sparing according to lip involvement. Reconstructive ALT flaps were of 2 designs, folded (F-ALT) and chimeric (C-ALT). Outcomes of oral feeding were analyzed using descriptive statistics, and differences between groups were compared using the Student t test.

RESULTS

We identified 233 patients who received oncologic ablation and free ALT flap reconstruction. There was no significant difference in functional recovery between the T&T and non-T&T groups (81.2% vs 73%, P = 0.137). However, among patients who succeeded in resuming oral feeding, lip-sparing patients had better functional recovery in terms of early oral feeding within 6 months and nasogastric tube removal compared with lip-resection patients (100% vs 83.3%, P = 0.001). Moreover, the F-ALT design resulted in a higher success rate in resuming oral feeding compared with the C-ALT design (90.5% vs 54.6%, P = 0.032).

CONCLUSIONS

Patients with head and neck cancer with T&T defects were associated with higher rates of secondary flap revision and a trend of delayed oral feeding. In the long term, improved oral feeding outcome with the F-ALT design was observed compared with the C-ALT design in the specific group with T&T defect.

IL-29 promoted obesity-induced inflammation and insulin resistance

Adipocyte-macrophage crosstalk plays a critical role to regulate adipose tissue microenvironment and cause chronic inflammation in the pathogenesis of obesity. Interleukin-29 (IL-29), a member of type 3 interferon family, plays a role in host defenses against microbes, however, little is known about its role in metabolic disorders. We explored the function of IL-29 in the pathogenesis of obesity-induced inflammation and insulin resistance. We found that serum IL-29 level was significantly higher in obese patients. IL-29 upregulated IL-1β, IL-8, and monocyte chemoattractant protein-1 (MCP-1) expression and decreased glucose uptake and insulin sensitivity in human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes through reducing glucose transporter 4 (GLUT4) and AKT signals. In addition, IL-29 promoted monocyte/macrophage migration. Inhibition of IL-29 could reduce inflammatory cytokine production in macrophage-adipocyte coculture system, which mimic an obese microenvironment. In vivo, IL-29 reduced insulin sensitivity and increased the number of peritoneal macrophages in high-fat diet (HFD)-induced obese mice. IL-29 increased M1/M2 macrophage ratio and enhanced MCP-1 expression in adipose tissues of HFD mice. Therefore, we have identified a critical role of IL-29 in obesity-induced inflammation and insulin resistance, and we conclude that IL-29 may be a novel candidate target for treating obesity and insulin resistance in patients with metabolic disorders.

The impacts of intra-arterial chemotherapy on head and neck microvascular reconstruction

BACKGROUND

For locally advanced head and neck cancers, intra-arterial (IA) chemotherapy is utilized for locoregional control with favorable results. The study aimed to evaluate the surgical outcomes of microsurgical reconstruction in head and neck cancer patients with IA chemotherapy METHODS: This cohort study retrospectively reviewed patients who underwent head and neck microsurgical reconstruction from January 2014 to August 2018. Patients with prior history of chemotherapy were included and categorized into two groups according to history of IA chemotherapy (IA group)/intravenous chemotherapy (IV group). Flap survival was evaluated along with microsurgical revision rates and complications. Recipient vessel specimens were analyzed by histological examination. A 1:1 propensity score matched analysis was performed.

RESULTS

The study cohort included 45 patients with IA chemotherapy and 201 patients with IV chemotherapy. After propensity score matching, the difference in total flap loss and microsurgical revision rates were nonsignificant between two groups. However, the IA group had significantly higher rates of arterial thrombosis (Odds ratio [OR] 4.98; 95%CI, 1.28-19.38; p = 0.021), wound-related complications (OR 3.30; 95%CI, 1.21-9.02; p = 0.02) and revision surgery within one month (OR 3.73; 95%CI, 1.10-12.64; p = 0.035). Based on histology, IA group vessels showed a higher intima/media ratio than the IV group (0.45 ± 0.06 versus 0.23 ± 0.03, p = 0.02) CONCLUSION: Despite treating local advanced head and neck cancers with good results, IA chemotherapy may cause subsequent deleterious effects on local tissue due to the high concentration of cytotoxic chemotherapeutic agents. Surgeons should be cautious in selection of recipient vessels when performing microvascular reconstruction.

Pre-treatment quality of life as a predictor of distant metastasis-free survival and overall survival in patients with head and neck cancer who underwent free flap reconstruction

PURPOSE

This study examined the prognostic associations of pre-treatment quality of life (QoL) with overall survival (OS) and distant metastasis-free survival (DFMS) among patients with head and neck cancer (HNC) who underwent free flap reconstruction.

METHODS

A cohort of 127 HNC patients who received free flap reconstruction between November 2010 and June 2014 at a hospital were recruited. Pre-treatment QoL was measured by the University of Washington Quality of Life Questionnaire, which contains six physical domains, including speech, swallowing, appearance, saliva, taste and chewing, as well as the six social-emotional domains of pain, activity, recreation, shoulder, mood, and anxiety. Cox regression analyses were performed.

RESULTS

Results showed that pre-treatment QoL was predictive of OS and DMFS. Of the domains, swallowing, chewing, speech, taste, saliva, pain and shoulder were demonstrated to be significant predictors of OS. Additionally, swallowing, chewing, speech, pain and activity were demonstrated making significant contributions to DMFS.

CONCLUSION

Our data supported that physical domains of pre-treatment QoL were predictors for OS and DFMS in HNC patients with free-flap reconstruction. Longitudinal studies are warranted to clarify the prognostic abilities of social-emotional domains. Information on pre-treatment QoL should be taken into account to individualize care plan for these patients, and hence prolong their survival.

Glycosaminoglycan-based hybrid hydrogel encapsulated with polyelectrolyte complex nanoparticles for endogenous stem cell regulation in central nervous system regeneration

The poor regenerative capability of stem cell transplantation in the central nervous system limits their therapeutic efficacy in brain injuries. The sustained inflammatory response, lack of structural support, and trophic factors deficiency restrain the integration and long-term survival of stem cells. Instead of exogenous stem cell therapy, here we described the synthesis of nanohybrid hydrogel containing sulfated glycosaminoglycan-based polyelectrolyte complex nanoparticles (PCN) to mimic the brain extracellular matrix and control the delivery of stromal-derived factor-1α (SDF-1α) and basic fibroblast factor (bFGF) in response to matrix metalloproteinase (MMP) for recruiting endogenous neural stem cells (NSC) and regulating their cellular fate. Bioactive factors are delivered by electrostatic sequestration on PCN to amplify the signaling of SDF-1α and bFGF to regulate NSC in vitro. In in vivo ischemic stroke model, the factors promoted neurological behavior recovery by enhancing neurogenesis and angiogenesis. These combined strategies may be applied for other tissue regenerations by regulating endogenous progenitors through the delivery of different kinds of glycosaminoglycan-binding molecules.

Multichanneled Nerve Guidance Conduit with Spatial Gradients of Neurotrophic Factors and Oriented Nanotopography for Repairing the Peripheral Nervous System

Peripheral nerve injuries, causing sensory and motor impairment, affect a great number of patients annually. It is therefore important to incorporate different strategies to promote nerve healing. Among the treatment options, however, the efficacy of nerve conduits is often compromised by their lack of living cells, insufficient growth factors, and absence of the extracellular matrix (ECM)-like structure. To improve the functional recovery, we aimed to develop a natural biodegradable multichanneled scaffold characterized with aligned electrospun nanofibers and neurotrophic gradient (MC/AN/NG) to guide axon outgrowth. The gelatin-based conduits mimicked the fascicular architecture of natural nerve ECM. The multichanneled (MC) scaffolds, cross-linked with microbial transglutaminase, possessed sustainable mechanical stability. Meanwhile, the release profile of dual neurotrophic factors, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), exhibited a temporal-controlled manner. In vitro, the differentiated neural stem cells effectively extended their neurites along the aligned nanofibers. Besides, in the treated group, the cell density increased in high NGF concentration regions of the gradient membrane, and the BDNF significantly promoted myelination. In a rabbit sciatic nerve transection in vivo model, the MC/AN/NG scaffold showed superior nerve recovery and less muscle atrophy comparable to autograft. By integrating multiple strategies to promote peripheral nerve regeneration, the MC/AN/NG scaffolds as nerve guidance conduits showed promising results and efficacious treatment alternatives for autologous nerve grafts.

Enzyme-crosslinked gene-activated matrix for the induction of mesenchymal stem cells in osteochondral tissue regeneration

The development of osteochondral tissue engineering is an important issue for the treatment of traumatic injury or aging associated joint disease. However, the different compositions and mechanical properties of cartilage and subchondral bone show the complexity of this tissue interface, making it challenging for the design and fabrication of osteochondral graft substitute. In this study, a bilayer scaffold is developed to promote the regeneration of osteochondral tissue within a single integrated construct. It has the capacity to serve as a gene delivery platform to promote transfection of human mesenchymal stem cells (hMSCs) and the functional osteochondral tissues formation. For the subchondral bone layer, the bone matrix with organic (type I collagen, Col) and inorganic (hydroxyapatite, Hap) composite scaffold has been developed through mineralization of hydroxyapatite nanocrystals oriented growth on collagen fibrils. We also prepare multi-shell nanoparticles in different layers with a calcium phosphate core and DNA/calcium phosphate shells conjugated with polyethyleneimine to act as non-viral vectors for delivery of plasmid DNA encoding BMP2 and TGF-β3, respectively. Microbial transglutaminase is used as a cross-linking agent to crosslink the bilayer scaffold. The ability of this scaffold to act as a gene-activated matrix is demonstrated with successful transfection efficiency. The results show that the sustained release of plasmids from gene-activated matrix can promote prolonged transgene expression and stimulate hMSCs differentiation into osteogenic and chondrogenic lineages by spatial and temporal control within the bilayer composite scaffold. This improved delivery method may enhance the functionalized composite graft to accelerate healing process for osteochondral tissue regeneration.

STATEMENT OF SIGNIFICANCE

In this study, a gene-activated matrix (GAM) to promote the growth of both cartilage and subchondral bone within a single integrated construct is developed. It has the capacity to promote transfection of human mesenchymal stem cells (hMSCs) and the functional osteochondral tissues formation. The results show that the sustained release of plasmids including TGF-beta and BMP-2 from GAM could promote prolonged transgene expression and stimulate hMSCs differentiation into the osteogenic and chondrogenic lineages by spatial control manner. This improved delivery method should enhance the functionalized composite graft to accelerate healing process in vitro and in vivo for osteochondral tissue regeneration.

Tailored design of multifunctional and programmable pH-responsive self-assembling polypeptides as drug delivery nanocarrier for cancer therapy

Breast cancer has become the second leading cause of cancer-related mortality in female wherein more than 90% of breast cancer-related death results from cancer metastasis to distant organs at advanced stage. The purpose of this study is to develop biodegradable nanoparticles composed of natural polypeptides and calcium phosphate (CaP) with sequential pH-responsivity to tumor microenvironments for active targeted drug delivery. Two different amphiphilic copolymers, poly(ethylene glycol)₃₄₀₀-aconityl linkage-poly(l-glutamic acid)₁₅-poly(l-histidine)₁₀-poly(l-leucine)₁₀ and LyP1-poly(ethylene glycol)₁₁₀₀-poly(l-glutamic acid)₁₅-poly(l-histidine)₁₀-poly(l-leucine)₁₀, were exploited to self-assemble into micelles in aqueous phase. The bio-stable nanoparticles provide three distinct functional domains: the anionic PGlu shell for CaP mineralization, the protonation of PHis segment for facilitating anticancer drug release at target site, and the hydrophobic core of PLeu for encapsulation of anticancer drugs. Furthermore, the hydrated PEG outer corona is used for prolonging circulation time, while the active targeting ligand, LyP-1, is served to bind to breast cancer cells and lymphatic endothelial cells in tumor for inhibiting metastasis. Mineralized DOX-loaded nanoparticles (M-DOX NPs) efficiently prevent the drug leakage at physiological pH value and facilitate the encapsulated drug release at acidic condition when compared to DOX-loaded nanoparticles (DOX NPs). M-DOX NPs with LyP-1 targeting ligand effectively accumulated in MDA-MB-231 breast cancer cells. The inhibition effect on cell proliferation also enhances with time, illustrating the prominent anti-tumor efficacy. Moreover, the in vitro metastatic inhibition model shows the profound inhibition effect of inhibitory nanoparticles. In brief, this self-assembling peptide-based drug delivery nanocarrier with multifunctionality and programmable pH-sensitivity is of great promise and potential for anti-cancer therapy.

STATEMENT OF SIGNIFICANCE

This tailored-design polypeptide-based nanoparticles with self-assembling and programmable stimulus-responsive properties enable to 1) have stable pH in physiological value with a low level of drug loss and effectively release the encapsulated drug with pH variations according to the tumor microenvironment, 2) enhance targeting ability to hard-to-treat breast cancer cells and activate endothelial cells (tumor region), 3) significantly inhibit the growth and prevent from malignant metastasis of cancer cells in consonance with promising anti-tumor efficacy, and 4) make tumors stick to localized position so that these confined solid tumors can be more accessible by different treatment modalities. This work contributes to designing a programmable pH-responsive drug delivery system based on the tailor-designed polypeptides.

Multi-functionalized carbon dots as theranostic nanoagent for gene delivery in lung cancer therapy

Theranostics, an integrated therapeutic and diagnostic system, can simultaneously monitor the real-time response of therapy. Different imaging modalities can combine with a variety of therapeutic moieties in theranostic nanoagents. In this study, a multi-functionalized, integrated theranostic nanoagent based on folate-conjugated reducible polyethylenimine passivated carbon dots (fc-rPEI-Cdots) is developed and characterized. These nanoagents emit visible blue photoluminescence under 360 nm excitation and can encapsulate multiple siRNAs (EGFR and cyclin B1) followed by releasing them in intracellular reductive environment. In vitro cell culture study demonstrates that fc-rPEI-Cdots is a highly biocompatible material and a good siRNA gene delivery carrier for targeted lung cancer treatment. Moreover, fc-rPEI-Cdots/pooled siRNAs can be selectively accumulated in lung cancer cells through receptor mediated endocytosis, resulting in better gene silencing and anti-cancer effect. Combining bioimaging of carbon dots, stimulus responsive property, gene silencing strategy, and active targeting motif, this multi-functionalized, integrated theranostic nanoagent may provide a useful tool and platform to benefit clinicians adjusting therapeutic strategy and administered drug dosage in real time response by monitoring the effect and tracking the development of carcinomatous tissues in diagnostic and therapeutic aspects.

Prognostic Factors of Survival From Intractable Oronasal Bleeding After Successful Transarterial Embolization

PURPOSE

To evaluate the prognostic factors that influence the survival of patients with traumatic intractable oronasal bleeding treated by transarterial embolization (TAE).

MATERIALS AND METHODS

Patients who received TAE for intractable oronasal bleeding in the National Taiwan University Hospital from 2002 through 2013 were included in the study. Retrospective reviews were undertaken to collect relevant clinical and neuroradiologic data that might be correlated with patients' survival. The Wilcoxon rank-sum test or Fisher exact test was adopted to analyze differences between the survival group and the mortality group. Odds ratios were estimated by univariate logistic regression.

RESULTS

TAE successfully controlled the bleeding in 24 of 26 patients (92.3%) who had severe craniofacial injury in the 12-year period. Of the 24 patients with successful TAE, 13 patients were discharged alive from the hospital. The overall survival rate was 50% (13 of 26). Significantly higher initial Glasgow Coma Scale (GCS) score (P = .01) and lower Injury Severity Score (ISS; P < .01) were present in the survival group than in the mortality group by the Wilcoxon rank-sum test. Moreover, patients with an ISS of at least 30, a GCS score lower than 9, initial hemoglobin level lower than 10 g/dL, and computed tomographic (CT) findings of a brain midline shift had statistically higher odds ratios predicting mortality than their counterparts as estimated by univariate logistic regression.

CONCLUSIONS

The results of this study showed that the combination of diagnostic angiography and therapeutic embolization is effective treatment for intractable oronasal bleeding in patients with severe craniofacial injury. The prognosis in patients who were rescued with successful TAE was statistically correlated with the severity of trauma and concomitant brain injury. An ISS of at least 30, a GCS score lower than 9, an initial hemoglobin level lower than 10, and CT findings of a brain midline shift were strong predictors for mortality.

Tailored design of electrospun composite nanofibers with staged release of multiple angiogenic growth factors for chronic wound healing

The objective of this research study is to develop a collagen (Col) and hyaluronic acid (HA) inter-stacking nanofibrous skin equivalent substitute with the programmable release of multiple angiogenic growth factors (vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and endothelial growth factor (EGF)) either directly embedded in the nanofibers or encapsulated in the gelatin nanoparticles (GNs) by electrospinning technology. The delivery of EGF and bFGF in the early stage is expected to accelerate epithelialization and vasculature sprouting, while the release of PDGF and VEGF in the late stage is with the aim of inducing blood vessels maturation. The physiochemical characterizations indicate that the Col-HA-GN nanofibrous membrane possesses mechanical properties similar to human native skin. The design of a particle-in-fiber structure allows growth factors for slow controlled release up to 1month. Cultured on biodegradable Col-HA membrane with four kinds of growth factors (Col-HA w/4GF), endothelial cells not only increase in growth rate but also form a better network with a thread-like tubular structure. The therapeutic effect of Col-HA w/4GF membrane on streptozotocin (STZ)-induced diabetic rats reveals an accelerated wound closure rate, together with elevated collagen deposition and enhanced maturation of vessels, as revealed by Masson's trichrome stain and immunohistochemical analysis, respectively. From the above, the electrospun Col-HA-GN composite nanofibrous skin substitute with a stage-wise release pattern of multiple angiogenic factors could be a promising bioengineered construct for chronic wound healing in skin tissue regeneration.

Magnetic field enhanced resonant tunneling in a silicon nanowire single-electron-transistor

We report fabrication, measurement and simulation of silicon single-electron-transistors made on silicon-on-insulator wafers. At T-2 K, these devices showed clear Coulomb blockade structures. An external perpendicular magnetic field was found to enhance the resonant tunneling peak and was used to predict the presence of two laterally coupled quantum dots in the narrow constriction between the source-drain electrodes. The proposed model and measured experimental data were consistently explained using numerical simulations.

Fabrication method of high-quality Ge nanocrystals on patterned Si substrates by local melting point control

The local melting point of a Ge thin film can be controlled by a hole-array pattern on the host Si substrate due to the variations in the stress distribution and the surface morphology induced by the pattern. A simple annealing process is developed from this effect to produce Ge NCs with a single-domain-crystal size over 20 nm, confirmed by transmission electron microscopy and Raman spectroscopy, from an electron-gun-evaporated Ge thin film on the patterned Si substrate. The effect of the dimensions of the hole array is also investigated. Photoluminescence observed around 1157 nm from some of the samples shows the possibility of improving the infrared emission capability by this proposed method.

Acute surgical treatment of perforated peptic ulcer in the elderly patients

BACKGROUND/AIMS

Emergency abdominal surgery is associated with high morbidity and mortality rates, especially in the elderly patients, but prompt diagnoses and treatment should not be delayed. We conducted a retrospective review (1) to identify risk factors for morbidity and mortality among elderly patients admitted for emergent surgery of perforated peptic ulcers; and (2) to determine whether there were any differences between those who are 70-79 years old and those 80 years old and older.

METHODOLOGY

94 patients who were older than 70 years old and underwent emergency surgery for perforated peptic ulcer between 2000 and 2004 in our institution were reviewed retrospectively. The following variables were followed: age, sex, comorbidity, previous medications, time from onset of symptoms/signs to surgery, time from arrival in emergent room to surgery, perioperative risks, operative findings, type of operation, morbidity, mortality and length of hospital stay.

RESULTS

The age, morbidity, mortality and the length of intensive care unit stay were increased in Group 2 (>80 yrs) than Group 1 (70 to 79 yrs), but they did not achieve significant differences statistically. Time from symptoms/signs to emergency room over 24 hours, American Society of Anesthesiologist grade over IV and limited procedure showed significant contributions to postoperative morbidity on univariate analysis. Comorbidity, time from emergency room to operation room over 12 hours, American Society of Anesthesiologists grade over IV, peri-operative blood transfusion, postoperative morbidity and duration of ICU stays over 5 days were significant factors contributed to mortality on univariate analysis. Further analysis showed comorbidity, peri-operative blood transfusion, and postoperative morbidity were independent and predictive factors of mortality on multivariate model.

CONCLUSIONS

Although perforated peptic ulcer in the elderly patients is associated with high morbidity and mortality, we should not delay the surgical intervention for patients with advanced age. Timely diagnosis and early surgical management of perforated peptic ulcers was imperative for elderly patients. The abdominal computer tomography was recommended in elderly patients for who had vague and atypical clinical symptoms/signs of perforated peptic ulcer. In addition, more attention should be paid to patients with preoperative comorbidities, peri-operative blood transfusion and post-operative morbidity for which were associated with high post-operative mortality.

Electroluminescence enhancement of SiGe/Si multiple quantum wells through nanowall structures

The enhancement of light extraction from Si(0.5)Ge(0.5)/Si multiple quantum wells (MQWs) with nanowall structures fabricated by electron cyclotron resonance (ECR) plasma etching is presented. It is shown that the ECR plasma treatment does not damage the crystalline quality. At a driving current of 5.5 × 10(6) A m(-2), the light output intensity of the MQWs with nanowall structures shows an enhancement of about 50% compared with that of the original MQWs. In addition to the enhanced light extraction, the improved optoelectronic properties are also attributed to the strain relaxation in nanowall structures.

Static conformation and dynamics of single DNA molecules confined in nanoslits

Nearly thirty years ago, Daoud and de Gennes derived the scaling predictions for the linear polymer chains trapped in a slit with dimension close to the Kuhn length; however, these predictions have yet to be compared with experiments. We have fabricated nanoslits with vertical dimension similar to the Kuhn length of ds-DNA (110nm) using standard photolithography techniques. Fluorescently labeled single DNA molecules with contour lengths L ranging from 4 to 75 microm were successfully injected into the slits and the chain molecules undergoing Brownian motions were imaged by fluorescence microscopy. The distributions of the chain radius of gyration and the two-dimensional asphericity were measured. It is found that the DNA molecules exhibit highly anisotropic shape and the mean asphericity is chain length independence. The shape anisotropy of DNA in our measurements is between two and three dimensions (2D and 3D). The static scaling law of the chain extension and the radius of gyration <R parallel>, <Rg> approximately L(nu) were observed with nuR(parallel)=0.65+/-0.02 and nu(Rg)=0.68+/-0.05. These results are close to the average value between two (nuR parallel,Rg=0.75) and three (nuR parallel,Rg=0.6) -dimensional theoretical value. The scaling of the extensional and rotational relaxation time are between Rouse model in nanoslits and Zimm model in the bulk solution, respectively. We show that the conformation and chain relaxation of DNA confined in a slit close to Kuhn length exhibit the quasi-two-dimensional behavior.

Beaming light from a subwavelength metal slit surrounded by dielectric surface gratings

In this article, we demonstrate that a subwavelength metal slit surrounded by dielectric surface gratings possesses a directional beaming effect. We propose a surface plasmon diffraction scheme to explain the three kinds of beaming conditions. The numerical simulations of the illustrative structures undertaken used a Finite Difference Time Domain (FDTD) Method and a Rigorous Coupled Wave Analysis (RCWA) Method. Our simulations were found to be consistent and in agreement with the experimental results. In comparison with other metal structures, we find that dielectric metal structures offer better performance as well as the advantage of being able to be efficiently mass produced for large volume industrial applications.

Removal of 2,4-dichlorophenol by suspended and immobilized Bacillus insolitus

In this experiment, Bacillus insolitus was isolated and selected from a mixed culture that have been acclimated to chlorophenols. Decomposition of chlorophenolic compounds will be studied using this pure culture in both suspended and immobilized form. The results are: at lower initial concentrations of 2,4-dichlorophenol (10-50 mg/l), immobilized Bacillus insolitus shows a higher removal of 2,4-dichlorophenol than Bacillus insolitus in suspended growth. When the 2,4-dichlorophenol concentration becomes higher (50-200 mg/l), both immobilized and suspended Bacillus insolitus have approximately the same efficiency for removal of 2,4-dichlorophenol. Higher concentrations of 2,4-dichlorophenol are inhibitive to the growth of either suspended or immobilized Bacillus insolitus. At lower concentrations of 2,4-dichlorophenol, immobilized mixed culture may have the same removal efficiency of 2,4-dichlorophenol as immobilized pure culture of Bacillus insolitus. But with regard to the overall 2,4-dichlorophenol removal efficiency, immobilized pure culture is considered to be superior to immobilized mixed culture.