High-Mobility Group Box 1 Inhibitor BoxA Alleviates Neuroinflammation-Induced Retinal Ganglion Cell Damage in Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) is a significant cause of vision loss and irreversible blindness worldwide. It is defined as retinal ganglion cell death and axon degeneration caused by injury. Optic nerve crush (ONC), a well-validated model of TON, activates retinal microglia and initiates neuroinflammation. High-mobility group box 1 (HMGB1), a non-histone chromosomal binding protein in the nucleus of eukaryotic cells, is an important inducer of microglial activation and pro-inflammatory cytokine release. The purpose of this study was to examine the protective effects and mechanism of the HMGB1 inhibitor BoxA to neuroinflammation-induced retinal ganglion cells (RGCs) damage in traumatic optic neuropathy. For that purpose, an optic nerve crush model was established in C57BL/6J mice at 10–12 weeks. Model mice received an intravitreal injection of PBS and the HMGB1 inhibitor BoxA. Our data demonstrated that HMGB1 expression increased after optic nerve crush. Retinal ganglion cell function and morphology were damaged, and retinal ganglion cell numbers were reduced after optic nerve crush. Intravitreal injection of BoxA after ONC can alleviate damage. Furthermore, BoxA reduced microglial activation and expression levels of nuclear factor κB (NF-kB), nucleotide-binding domain, leucine-rich repeat containing protein 3 (NLRP3), and apoptosis-associated speck-like protein containing a CARD (ASC) in experimental ONC mice. In summary, HMGB1 mediates NLRP3 inflammasome via NF-kB to participate in retinal inflammatory injury after ONC. Thus, intravitreal injection of BoxA has potential therapeutic benefits for the effective treatment of RGC death to prevent TON.

First Report of Epicoccum sorghinum Causing Leaf Spot on Paeonia suffruticosa in China

Tree peony (Paeonia suffruticosa Andr.; Paeoniaceae) is highly valued in Chinese culture for their ornamental and medicinal benefits in anti-inflammation, anti-arrhythmia, activating the immune system and protecting the cardiovascular system (Zhai et al. 2020). In May from 2019 to 2021, leaf spot symptoms were observed on tree peony in an area of 0.8 hm2 in Bozhou, Anhui Province, China; with a disease incidence of 35%. Initially, black-brown spots (0.5-2.4 mm) appeared on the leaves, as the disease developed, the spots enlarged to form round, black lesions. Small pieces of tissue taken from the margins of lesions were surface-disinfected by 75% ethanol for 20 s followed by 0.1% mercuric chloride for 3 min, rinsed with distilled sterile water for three times, placed on potato dextrose agar (PDA) at 25 ºC for 7 days in the dark.Fifteen single spore isolates were obtained as described (Dong 2009). When cultured on PDA for 10 days, colonies were white, villose, then became gray-brown, with the reverse side becoming reddish-brown; Chlamydospores globose or irregular shaped, dark brown, unicellular or multicellular (4.3 to 12.2 × 13.1 to 33.7 µm) (n = 200). Pycnidia were black-brown, mostly spheroid, and 86 to 128 × 110 to 197 µm (n = 50); Conidia were hyaline, ellipsoidal, unicellular, aseptate, and 4.1 to 5.2 × 1.8 to 2.4 µm (n = 200) . The DNA of a representative isolate AF21-1-2 was extracted using the CTAB protocol (Doyle and Doyle 1987). The rDNA internal transcribed spacer (ITS), β-tubulin (TUB) and 28s nrDNA (LSU) genes were amplified and sequenced using the primers ITS1/ITS4 (White et al. 1990), Bt2a/Bt2b (Glass et al. 1995), and LR5/LR0R (Vilgalys and Hester, 1990), respectively (OK485136, OK631973, and ON358331). BLASTn analysis showed that the ITS, TUB, and LSU sequences had 99% (497/501 bp), 98% (530/539 bp), and 99% (878/882 bp) identity with the Epicoccum sorghinum isolates ESCZO20 (MN944541), CZ01 (MT254851) and Dl16-338 (LN907481), respectively. Maximum likelihood phylogenetic tree revealed that AF21-1-2 clustered with E. sorghinum isolates. For pathogenicity test, leaves of 3-year-old healthy tree peony plant in the field were inoculated with 105 conidia/ml spore suspension (prepared with 30-day-old cultures on PDA), added with 0.1% (v/v) Tween-80. Ten surface-sterilized leaves per plant were sprayed with 30 ml suspension until runoff, a total of 3 plants were inoculated. Leaves sprayed with sterilized water serve as a negative control. Each plant was covered with a plastic bag to maintain high relative humidity at 15 to 23°C and was monitored daily for symptom development. Typical symptoms appeared on more than 80% of the leaves after 7 days of inoculation, while control leaves remained symptomless. Cultures isolated from inoculated leaves had the same morphological and molecular traits as those that were previously used to test Koch's postulates. Based on the morphological and molecular characteristics, the causal agent on tree peony was identified as E. sorghinum (Aveskamp et al. 2010). To our knowledge, this is the first report of E. sorghinum causing leaf spot on tree peony in China. The disease will cause serious economic loss for tree peony if it is not managed properly. This report may provide the basis for diagnosis and control of the disease.

Management of edoxaban in patients undergoing multiple procedures: a subanalysis of the EMIT-AF/VTE program

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Daiichi Sankyo

Background

Patients with atrial fibrillation (AF) or venous thromboembolism (VTE) receiving long-term direct oral anticoagulant (DOAC) therapy undergo diagnostic or therapeutic procedures at a rate of approximately 10% annually. The prospective Global EMIT-AF/VTE program (Edoxaban Management in Diagnostic and Therapeutic Procedures; NCT02950168, NCT02951039) demonstrated that physician-guided periprocedural management of the DOAC edoxaban in these patients was associated with low bleeding and thromboembolic event rates. It is unclear whether the experience of a previous (index) procedure influences the periprocedural management of subsequent procedures.

Purpose

To analyze differences in periprocedural edoxaban management in patients on chronic anticoagulation therapy undergoing multiple diagnostic or therapeutic procedures.

Methods

Baseline characteristics were recorded in patients enrolled in the EMIT-AF/VTE program who underwent multiple procedures. Details of periprocedural edoxaban interruption were collected from patients who underwent two procedures of the same European Heart Rhythm Association (EHRA) bleeding risk level or procedural type. Only data from the index and second procedure of the same category were included in this analysis; procedures conducted less than 7 days apart were excluded. All analyses are exploratory and descriptive in nature.

Results

Among 227 patients who underwent multiple procedures, the most common types were vascular and gastrointestinal (GI) procedures. Patients had a mean ± standard deviation age of 72.1 ± 9.8 years, a CHA2DS2-VASc score of 3.2 ± 1.6, a HAS-BLED score of 1.9 ± 1.0, and were mostly male (67.0%). Patients who underwent low/minor risk procedures were less likely to undergo edoxaban interruption with their second procedure compared with their index procedure (Figure 1A), and the median interruption duration was shorter for the second procedure (Table 1). A second high risk procedure was associated with a higher rate of both pre- and postprocedural edoxaban interruption compared with a patient’s index procedure, but treatment resumed earlier (Figure 1B). Patients who underwent vascular procedures had a lower rate of pre- and postprocedural interruption and a shorter interruption time with their second procedure (Table 1). Conversely, patients who underwent GI procedures experienced pre- and postprocedural interruption more often for their second procedure. The median interruption duration was longer for GI procedures than for vascular procedures (Table 1).

Conclusion

Overall, periprocedural edoxaban interruption varied by procedural bleeding risk and type. Edoxaban interruption patterns differed between index and second procedures, indicating that periprocedural edoxaban management may be influenced by the experience of previous procedures.

First live birth in China after cryopreserved ovarian tissue transplantation to prevent premature ovarian insufficiency

OBJECTIVE

This article reports the first live birth after cryopreserved ovarian tissue transplantation to prevent premature ovarian insufficiency in China.

METHODS

A patient with myelodysplastic syndrome received ovarian tissue cryopreservation before hematopoietic stem cell transplantation, and six ovarian cortex strips were thawed and transplanted into her peritoneal pocket 2 years later.

RESULTS

Pregnancy occurred spontaneously 27 months after grafting, and a healthy girl was born at 38 weeks gestation. Until now, the child has developed normally without any major diseases.

CONCLUSIONS

We report the first live birth resulting from ovarian tissue cryopreservation and transplantation in China.

Acritarch-like Microorganisms from the 1.9 Ga Gunflint Chert, Canada

Fossil evidence of eukaryotic life older than 1.8 Ga has long been debated because known fossils of that age usually lack cellular micro- and ultra-structures that bear strong affinities to eukaryotes. These include fossils of the ∼1.9 Ga Gunflint Chert microbiota that, despite being exceptionally well preserved, have suffered from cellular degradation, which poses challenges to studying their delicate cellular structures. In this study, we use an extended-focal-depth imaging technique, in combination with scanning electron microscopy, to document multiple types of large (10-35 μm diameter), cyst-like bodies based on distinctive details such as (1) radially arranged internal strands similar to those in some acritarchs and dinoflagellates; (2) regularly spaced long tubular processes, stubby pustules, and/or robust podia on the cell surface; (3) reticulate cell-wall sculpturing such as scale-like tubercles, pits, and ridges; and (4) internal bodies that may represent membrane-bound organelles. These micro- and ultra-structures provide strong morphological evidence for the presence of protists in the late Paleoproterozoic.

[Prevalence and frequencies of human papilloma virus types in adenocarcinoma in situ of the uterine cervix]

Objective: To examine the prevalence and frequencies of human papillomavirus (HPV) genotypes in cervical adenocarcinoma in situ (AIS). Methods: The cases of cervical AIS with concurrent tests of cytology and HPV typing from January 2007 to February 2020 in the Obstetrics and Gynecology Hospital of Fudan University were collected and analyzed. Results: A total of 478 cases of cervical AIS were obtained. The average age of the patients was 39.4 years (range, 19-81 years). The largest age group was 30-39 years (44.8%), followed by 40-49 years (34.7%). Among the 478 patients, 355 underwent high-risk HPV (hrHPV) testing and had a hrHPV-positive rate of 93.8%. Of the 355 patients, 277 also underwent HPV typing and were mostly positive for either or both HPV16 and HPV18 (93.1%), with 55.6% positive for HPV18 and 48.7% positive for HPV16. Among the 478 cases, 266 cases (55.6%) were diagnosed with both AIS and squamous intraepithelial lesion (SIL), while 212 cases (44.4%) were diagnosed with only AIS. Patients infected with HPV16 in the AIS and SIL group significantly outnumbered those in the AIS alone group (P<0.05). Moreover, the rate of positive cytology was 55.9% (167/299 cases), while that of negative cytology was 44.1% (132/299). Among the 109 patients with negative cytology results and co-tested hrHPV, there were 101 HPV-positive cases (92.7%), of which 88 cases were subject to HPV typing and showed an HPV16/18 positive rate of 94.3% (83/88 cases). Conclusions: The combination of HPV typing and cytological screening can maximize the detection rate of cervical AIS, and should continue to be utilized, ideally on a larger scale, in the future.

Therapeutic Potential of Umbilical Cord MSC in Crohn's Disease Is Related to Regulation of the Relative Content and Function of Th17 Lymphocytes

Inflammatory bowel diseases, including Crohn's disease and ulcerative colitis, are chronic and relapsing autoimmune disorders with active participation of Th17 lymphocytes. In the recent treatment strategy of Crohn's disease, human umbilical cord matrix (Wharton's jelly) has been reported having immune privilege. In this study, primary umbilical cord MSC were isolated and cultured for further treatment, their immunophenotype and functional features were confirmed by flow cytometry and adipogenesis, osteogenesis, and chondrogenesis assays. Peripheral blood mononuclear cells (PBMC) were isolated from 11 patients with fistulizing Crohn's disease and 14 healthy volunteers, and the proportions of CD8-CD17A⁺T lymphocytes and CD3⁺T cells in these samples cultured in the presence or absence of umbilical cord MSC were analyzed by flow cytometry. In addition, proliferation of T cells was assessed by CFSE staining. In PBMC samples from patients with Crohn's disease, the content of CD8-CD17A⁺T lymphocytes was higher than in samples from heathy controls, however, co-culturing with umbilical cord MSC decreased the proportion of CD8-CD17A⁺T lymphocytes in PBMC samples isolated from Crohn's disease patients. Additionally, co-culturing of PBMC from Crohn's disease patients with umbilical cord MSC improved T cells function, including CD3⁺T cells level and T cells proliferation. These results suggest that umbilical cord MSC treatment could alleviate elevation CD8-CD17A⁺T lymphocyte in Crohn's disease patients and modulate T cells dysfunctions, which implies that umbilical cord MSC might be a promising strategy for Crohn's disease patients.

[Stereotactic body radiation therapy for patients with lung and liver oligometastases from colorectal cancer: a phase Ⅱ trial]

Objective: To explore the safety and effectiveness of stereotactic body radiation therapy (SBRT) for oligometastases from colorectal cancer (CRC). Methods: This is a prospective, single-arm phase Ⅱ trial. Patients who had histologically proven CRC, 1 to 5 detectable liver or lung metastatic lesions with maximum diameter of any metastases ≤5 cm were eligible. SBRT was delivered to all lesions. The primary endpoint was 3-year local control (LC). The secondary endpoints were treatment-related acute toxicities of grade 3 and above, 1-year and 3-year overall survival (OS) and progression free survival (PFS). Survival analysis was performed using the Kaplan-Meier method and Log rank test. Results: Petients from 2016 to 2019 who were treated in Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. Forty-eight patients with 60 lesions were enrolled, including 37 liver lesions and 23 lung lesions. Forty-six patients had 1 or 2 lesions, with median diameter of 1.3 cm, the median biologically effective dose (BED(10)) was 100.0 Gy. The median follow-up was 19.5 months for all lesions. Twenty-five lesions developed local failure, the median local progression free survival was 15 months. The 1-year LC, OS and PFS was 70.2% (95% CI, 63.7%~76.7%), 89.0% (95% CI, 84.3%~93.7%) and 40.4% (95%CI, 33.0%~47.8%). The univariate analysis revealed that planning target volume (PTV) and total dose were independent prognostic factors of LC (P<0.05). For liver and lung lesions, the 1-year LC, OS and PFS was 58.7% and 89.4% (P=0.015), 89.3% and 86.5% (P=0.732), 30.5% and 65.6% (P=0.024), respectively. No patients developed acute toxicity of grade 3 and above. Conclusion: SBRT is safe and effective treatment method for oligometastases from CRC under precise respiratory motion management and robust quality assurance.

[Evaluation of the level of carotid bifurcation and the morphology of extracranial internal carotid artery in patients with carotid stenosis by color doppler ultrasound and digital subtraction angiography]

Objective: To evaluate the value of color Doppler ultrasound and digital subtraction angiography (DSA) in evaluating the level of carotid bifurcation and the morphology of extracranial internal carotid artery in patients with atherosclerotic carotid stenosis. Methods: The carotid artery examination data of 186 patients with atherosclerotic carotid stenosis who underwent carotid DSA and color Doppler ultrasound in Shanghai Changzheng Hospital from July 2017 to June 2019 were retrospectively analyzed, including 154 males and 32 females, with ages ranging from 36 to 84 (66±8) years old. The correlation between the position of carotid bifurcation and the level of cervical spine, the distance from the position of carotid bifurcation to mandibular angle, the correlation of the level of bifurcation with the length of neck, and the incidence of carotid distortion were analyzed. Results: DSA showed that the most common position of carotid bifurcation was at C3 level on the left [37.3% (56/150)], and at C3-C4 level on the right [33.6% (42/125)], and the highest position was at C2 level on the left, and at C2-C3 levels on the right, while the lowest level on both sides was at C5 level. The incidence of high bifurcation of left carotid artery (C3 and above) was 46% (69/150), which was higher than that of right carotid artery [21.6% (27/125), P<0.001]. The incidence of high carotid bifurcation in men and women was 33.2% (76/229) and 43.5% (20/46), respectively, with no significant difference (P = 0.182). Carotid ultrasound showed that the distance between the left carotid bifurcation and the mandibular angle was (3.0±1.3) cm, which was shorter than that on the right [(3.4±1.2) cm] (P<0.001). The distance between carotid bifurcation and mandibular angle in men and women was (3.2±1.2) cm and (3.3±1.0) cm, respectively, with no significant difference (P = 0.093). There was no significant correlation between carotid bifurcation level and carotid length (right: r = 0.02, P = 0.091; left: r = 0.01, P = 0.927). The incidence of carotid artery distortion was 28.1% (9/32) in women and 15.6% (24/154) in men, with no significant difference (P = 0.091). The incidence of right carotid artery distortion in high bifurcation group was 59.3% (16/27), which was higher than that in non-high bifurcation group [3.1% (3/98)] (P<0.001). Likewise, the incidence of left carotid artery distortion in high bifurcation group was 30.4% (21/69), which was higher than that in non-high bifurcation group [2.5% (2/81)] (P<0.001). Conclusions: The bifurcation position of left carotid artery in patients with atherosclerotic carotid stenosis is higher than that of the right. Patients with high bifurcation of carotid artery are more likely to be complicated with carotid distortion. Preoperative color doppler ultrasound combined with DSA can evaluate the distortion of extracranial carotid artery, thereby providing reference for the selection of surgical methods.

[Bioinformatics screening and analysis of key differentially expressed genes characteristics in nonalcoholic fatty liver disease]

Objective: To screen and analyze the key differentially expressed genes characteristics in nonalcoholic fatty liver disease (NAFLD) with bioinformatics method. Methods: NAFLD-related expression matrix GSE89632 was downloaded from the GEO database. Limma package was used to screen differentially expressed genes (DEGs) in healthy, steatosis (SS), and nonalcoholic steatohepatitis (NASH) samples. WGCNA was used to analyze the output gene module. The intersection of module genes and differential genes was used to determine the differential genes characteristic, and then GO function and KEGG signaling pathway enrichment analysis were performed. The protein-protein interaction network (PPI) was constructed using the online website STRING and Cytoscape software, and the key (Hub) genes were screened. Finally, R software was used to analyze the receiver operating characteristic curve (ROC) of the Hub gene. Results: 92 differentially expressed genes characteristic were obtained through screening, which were mainly enriched in inflammatory response-related functions of "lipopolysaccharide response and molecular response of bacterial origin", as well as cancer signaling pathways of "proteoglycan in cancer" and "T-cell leukemia virus infection-related". 10 hub genes (FOS, CXCL8, SERPINE1, CYR61, THBS1, FOSL1, CCL2, MYC, SOCS3 and ATF3) had good diagnostic value. Conclusion: The differentially expressed hub genes among the 10 NAFLD disease-related characteristics obtained with bioinformatics analysis may become a diagnostic and prognostic marker and potential therapeutic target for NAFLD. However, further basic and clinical studies are needed to validate.

A249 RETROSPECTIVE CHART REVIEW OF PATIENTS WITH MALNUTRITION REQUIRING ADVANCED NUTRITIONAL SUPPORT POST BARIATRIC SURGERY

Background

Obesity is a global pandemic with a steady increase in global BMI since 1975. Bariatric surgery is an effective treatment for patients with severe obesity in order to sustain long-term weight loss and reduce comorbidity burden and mortality associated with obesity. However, post-bariatric surgery patients face nutritional complications ranging from micronutrient deficiencies to intestinal failure requiring total parenteral nutrition (TPN). From our institution of home TPN patients, 6.4% of patients had bariatric surgery. Intestinal failure is a burdensome diagnosis for patients, and there is a paucity of literature characterizing patients post-bariatric surgery who develop intestinal failure.

Aims

We aim to identify the patient characteristics, surgical details, and nutritional traits that predisposed patients to developing intestinal failure requiring advanced nutritional support.

Methods

This is a retrospective chart review of 48 patient admitted to the Royal Alexandra Hospital post-bariatric surgery for nutritional support and followed by the TPN program dieticians and nurses.

Results

Our results show the mean BMI was 49.94 kg/m2 pre-bariatric surgery. Interestingly, the mean BMI at time of hospitalization for bariatric-surgery related complications was 33.210 kg/m2 which is classified as overweight but most of patients were severely malnourished with SGA C (43.8%), SGA B (29.17%), and 8.3% were SGA A. Patients requiring parenteral nutrition post-bariatric surgery are mostly female, developed barriers to oral intake, 15% engaged in medical tourism, 58.3% had an underlying mental health diagnosis, and only 18.8% were on a multivitamin even though it is standard of post-bariatric surgery care. The time between initial bariatric surgery to hospital admission was 11.2 years, and most required ≥1 revisional surgery. The mean age at bariatric surgery was 33.2-years old and the average age at initial hospitalization was 48.9-years old. Patients requiring ≥2 admissions had vertical band gastroplasty or sleeve gastrectomy (both 36.8%) while 21.1% had Roux-en-Y gastric bypass. Of these patients, 39.6% of patients required ≥2 hospital admissions and the mean total days spent in hospital was 57.15 days. While these complications are uncommon, these patients result in multiple prolonged hospitalizations and can be difficult to manage.

Conclusions

Overall, the results of our study will allow the multidisciplinary teams that care for post-bariatric surgery patients to identify patients at risk of intestinal failure and potentially intervene with early enrollment into home nutrition program. With increasing awareness, patients at higher risk can be closely monitored in order to prevent micronutrient deficiencies before they progress to intestinal failure and require lifetime parenteral nutrition.

Funding Agencies

None

Levosimendan in intensive care and emergency medicine: literature update and expert recommendations for optimal efficacy and safety

The inodilator levosimendan, in clinical use for over two decades, has been the subject of extensive clinical and experimental evaluation in various clinical settings beyond its principal indication in the management of acutely decompensated chronic heart failure. Critical care and emergency medicine applications for levosimendan have included postoperative settings, septic shock, and cardiogenic shock. As the experience in these areas continues to expand, an international task force of experts from 15 countries (Austria, Belgium, China, Croatia, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Spain, Sweden, Switzerland, and the USA) reviewed and appraised the latest additions to the database of levosimendan use in critical care, considering all the clinical studies, meta-analyses, and guidelines published from September 2019 to November 2021. Overall, the authors of this opinion paper give levosimendan a "should be considered" recommendation in critical care and emergency medicine settings, with different levels of evidence in postoperative settings, septic shock, weaning from mechanical ventilation, weaning from veno-arterial extracorporeal membrane oxygenation, cardiogenic shock, and Takotsubo syndrome, in all cases when an inodilator is needed to restore acute severely reduced left or right ventricular ejection fraction and overall haemodynamic balance, and also in the presence of renal dysfunction/failure.

[Effects of N-trimethyl chitosan-recombinant tissue factor pathway inhibitor complex on avulsion flap with roll compaction in rat]

Objective: To investigate the effect of N-trimethyl chitosan-recombinant tissue factor pathway inhibitor (rTFPI) complex on avulsion flap with roll compaction in rat. Methods: The experimental methods were adopted. The N-trimethyl chitosan-rTFPI complex solution was prepared by ion cross-linking method. The morphology of the complex was observed by scanning electron microscope, and its diameter was measured. The encapsulation rate of rTFPI in the complex and drug loading rate of the complex was determined and calculated by enzyme-linked immunosorbent assay (ELISA) method (n=3). The concentration of rTFPI in the solution at 0, 10, 30, 45, 60, 90, 120, 240 minutes of storage was measured by ELISA method to observe the release of rTFPI, and its half-life was calculated (n=3). Twenty-four 6-week-old male Sprague-Dawley rats were divided into phosphate buffered saline (PBS) group, N-trimethyl chitosan alone group, rTFPI alone group, and N-trimethyl chitosan-rTFPI group according to the random number table, with 6 rats in each group. The avulsion flaps with roll compaction were prepared on the backs of rats with pedicles located on the line of the bilateral iliac spine and lifted from the surface of the muscle membrane. One injection of corresponding reagents was carried out immediately after in-situ suture and on post operation day (POD) 1, 2, and 3. General changes of the flap were observed on POD 1, 3, and 7. On POD 7, the survival area of the flap was measured and the survival rate of the flap was calculated; the flaps were divided into pedicle, proximal, middle, and distal segments, and the blood perfusion in the proximal, middle, and distal segment tissue of the flap was detected by the laser speckle blood flow imager; tissue samples in the middle of the flap were cut and stained with hematoxylin and eosin to observe the changes in tissue structure and the infiltration of inflammatory cells, and the numbers of embolized blood vessels and new blood vessels per 100 times visual field were counted. Data were statistically analyzed with one-way analysis of variance and least significant difference test. Results: The N-trimethyl chitosan-rTFPI complex had an irregular spherical structure with a diameter of 150-200 nm. The encapsulation rate of rTFPI in the complex and drug loading rate of the complex were (88.7±2.1)% and (2.83±0.09)%, respectively. The concentration of rTFPI in the solution of the N-trimethyl chitosan-rTFPI complex gradually increased with prolonged storage time, and the release was basically stable at 90 min, with half-life of (651±36) min. On POD 1, the distal parts of flaps of rats in N-trimethyl chitosan alone group darkened significantly. On POD 3, scabs and necrosis were relatively mild on the distal segment of the flaps of rats in rTFPI alone group and N-trimethyl chitosan-rTFPI group as compared with those of the other two groups. On POD 7, the necrosis boundaries of the flaps of rats in each group were clear. On POD 7, the flap survival rates of rats in rTFPI alone group and N-trimethyl chitosan-rTFPI group were (63±7)% and (73±5)%, respectively, which were significantly higher than (41±3)% in PBS group and (52±7)% in N-trimethyl chitosan alone group. Moreover, the flap survival rate of rats in N-trimethyl chitosan-rTFPI group was significantly higher than that in rTFPI alone group (P<0.05). On POD 7, the flaps of rats in each group had blood perfusion; the blood perfusion values in the proximal segment tissue of the rat flaps in N-trimethyl chitosan alone group and the blood perfusion values in the proximal, middle, and distal segment tissue of the rat flaps in rTFPI alone group and N-trimethyl chitosan-rTFPI group were significantly higher than those in PBS group (P<0.05 or P<0.01); the blood perfusion values in the distal segment tissue of the rat flaps in rTFPI alone group and the blood perfusion values in the middle and distal segment tissue of the rat flaps in N-trimethyl chitosan-rTFPI group were significantly higher than those in N-trimethyl chitosan alone group (P<0.05 or P<0.01); the blood perfusion value in the middle segment tissue of the rat flaps in N-trimethyl chitosan-rTFPI group was significantly higher than that in rTFPI alone group (P<0.01). On POD 7, inflammatory cells infiltrated more and cell edema was obvious in the middle segment tissue of the rat flaps in PBS group and N-trimethyl chitosan alone group. Compared with those of the previous two groups, the inflammation degrees in the middle segment tissue of the rat flaps in rTFPI alone group and N-trimethyl chitosan-rTFPI group were significantly milder, the number of embolized blood vessels was significantly decreased (P<0.05 or P<0.01), and the number of new blood vessels was significantly increased (P<0.05 or P<0.01). Compared with that of rTFPI alone group, the number of new blood vessels in the middle segment tissue of the rat flaps in N-trimethyl chitosan-rTFPI group increased significantly (P<0.05). Conclusions: The effect of sustained release of rTFPI can be achieved by loading rTFPI with N-trimethyl chitosan. Compared with rTFPI alone, the N-trimethyl chitosan-rTFPI complex can further improve the blood perfusion of the avulsion flaps with roll compaction in rat and improve the survival rate of the flap.