Correction: ECM-based bioadhesive hydrogel for sutureless repair of deep anterior corneal defects

Correction for 'ECM-based bioadhesive hydrogel for sutureless repair of deep anterior corneal defects' by Safieh Boroumand et al., Biomater. Sci., 2024, https://doi.org/10.1039/d4bm00129j.

ECM-based bioadhesive hydrogel for sutureless repair of deep anterior corneal defects

Corneal transplantation is the gold standard treatment for corneal-related blindness; however, this strategy faces challenges such as limited donor cornea, graft rejection, suture-related complications, and the need for specialized equipment and advanced surgical skills. Development of tissue adhesives for corneal regeneration is of great clinical value. However, currently available corneal tissue sealants pose challenges, such as lack of safety, biocompatibility, and desired mechanical properties. To meet these requirements simultaneously, a bovine stromal corneal extracellular matrix (dCor) was used to design a bioadhesive photocurable hydrogel based on gelatin methacrylate (GelMA) and polyethylene glycol diacrylate (PEGDA) hydrogels (dCor/Gel-PEG). Integration of dCor into the dual networks of GelMA and PEGDA (Gel-PEG) led to a bioadhesive hydrogel for curing corneal defects, which could be crosslinked by Irgacure 2959 within 5 min ultraviolet irradiation. The viability of corneal stromal stem cells (CSSCs) was improved on the dCor/Gel-PEG hydrogel in comparison to the Gel-PEG hydrogel. The gene expression profile supported the keratocyte differentiation of CSSCs seeded on dCor/Gel-PEG via increased KERA and ALDH, with inhibited myofibroblast transdifferentiation via decreased α-SMA due to the presence of dCor. Interestingly, the dCor/Gel-PEG hydrogel exhibited favorable mechanical performance in terms of elasticity and bioadherence to the host corneal stroma. Ex vivo and in vivo examinations proved the feasibility of this hydrogel for the sutureless reconstruction of deep anterior corneal defects with promising histopathological results.

3D-printing of alginate/gelatin scaffold loading tannic acid@ZIF-8 for wound healing: In vitro and in vivo studies

In the present study, ZIF-8 metal-organic framework (MOF) modified with Tannic acid (TA@ZIF-8) was synthesized and impregnated in alginate-gelatin (Alg-Gel) hydrogel. The Alg-Gel scaffolds containing 0, 5, and 10 % of TA@ZIF-8 were fabricated through the 3D printing method specifically denoted as Alg-Gel 0 %, Alg-Gel 5 %, and Alg-Gel 10 %. XRD, FTIR, FESEM, and EDX physically and chemically characterized the synthesized ZIF-8 and TA@ZIF-8 MOFs. Besides, Alg-Gel containing TA@ZIF-8 prepared scaffolds and their biological activity were also evaluated. SEM images verified the nano-size formation of MOFs. Improved swelling and decreased degradation rates after adding TA@ZIF-8 were also reported. Increased compression strength from 0.628 to 1.63 MPa in Alg-Gel 0 % and Alg-Gel 10 %, respectively, and a 2.19 increase in elastic modulus in Alg-Gel 10 % scaffolds were exhibited. Biological activity of scaffolds, including Live-dead and Cell adhesion, antibacterial, in-vivo, and immunohistochemistry assays, demonstrated desirable fibroblast cell proliferation and adhesion, increased bacterial growth inhibition zone, accelerated wound closure and improved expression of anti-inflammatory cytokines in Alg-Gel 10 % scaffolds. The findings of this study confirm that Alg-Gel 10 % scaffolds promote full-thickness wound healing and could be considered a potential candidate for full-thickness wound treatment purposes.

Characterization and in vivo evaluation of a fabricated absorbable poly(vinyl alcohol)-based hernia mesh

The most widely taken medical approach toward hernia repair involves the implementation of a prosthetic mesh to cover the herniated site and reinforce the weakened area of the abdominal wall. Biodegradable meshes can serve as biocompatible grafts with a low risk of infection. However, their major complication is associated with a high rate of degradation and hernia recurrence. We proposed a facile and cost-effective method to fabricate a poly(vinyl alcohol)-based mesh, using the solution casting technique. The inclusion of zinc oxide nanoparticles, citric acid, and three cycles of freeze-thaw were intended to ameliorate the mechanical properties of poly(vinyl alcohol). Several characterization, cell culture, and animal studies were conducted. Swelling and water contact angle measurements confirmed good water uptake capacity and wetting behavior of the final mesh sample. The synthesized mesh acquired a high mechanical strength of 52.8 MPa, and its weight loss was decreased to 39 %. No cytotoxicity was found in all samples. In vivo experiments revealed that less adhesion and granuloma formation, greater tissue integration, and notably higher neovascularization rate were resulted from implanting this fabricated hernia mesh, compared to commercial Prolene® mesh. Furthermore, the amount of collagen deposition and influential growth factors were enhanced when rats were treated with the proposed mesh instead of Prolene®.

Evaluation of colonic anastomosis healing using hybrid nanosheets containing molybdenum disulfide (MOS2) scaffold of human placental amniotic membrane and polycaprolactone (PCL) in rat animal model

Anastomosis is a standard technique following different conditions such as obstruction, tumor, and trauma. Obstruction, adhesion, or anastomosis leakage can be some of its complications. To improve healing and prevent postoperative complications, we design a hybrid scaffold containing acellular human amniotic membranes and polycaprolactone-molybdenum disulfide nanosheets for colon anastomosis. The animal model of colocolonic anastomosis was performed on two groups of rats: control and scaffold. The hybrid scaffold was warped around the anastomosis site in the scaffold group. Samples from the anastomosis site were resected on the third and seventh postoperative days for histopathological and molecular assessments. Histopathologic score and burst pressure had shown significant improvement in the scaffold group. No mortality and anastomosis leakage was reported in the scaffold group. In addition, inflammatory markers were significantly decreased, while anti-inflammatory cytokines were increased in the scaffold group. The result indicates that our hybrid scaffold is a proper choice for colorectal anastomosis repair by declining postoperative complications and accelerating healing.

Evaluation of the Farsi-translated Hemorrhoidal Disease Symptom Score and Short Health Scale questionnaires in patients with hemorrhoid disease: A cross-sectional study

Background and Aims

The Hemorrhoidal Disease Symptom Score (HDSS) is a tool that is scored based on five main symptoms: pain, bleeding, itching, soiling, and prolapse. Furthermore, the Short Health Scale (SHS) is a measurement tool of subjective health and health-related quality of life. This study was performed to validate the Farsi-translated Hemorrhoidal Disease Symptom Score (HDSS), and Scale Short Health Scale adapted for hemorrhoidal disease (SHS-HD) as a measure of symptom severity in patients with hemorrhoid disease.

Methods

In this study, HDSS and SHS-HD were translated into Farsi. Participants with confirmed hemorrhoid disease completed the questionnaire. Subsequently, the questionnaire's discriminative validity, convergent validity, reliability, sensitivity, and specificity were evaluated.

Results

Data from 31 patients were analyzed (mean age 39.68; 71% male). The results of the analysis showed good internal consistency as Cronbach's α for HDSS and SHS were 0.994 and 0.995 respectively. Spearman's correlation coefficient for the test-retest comparison was 0.986 (p < 0.01). The responses demonstrated good convergent validity. Moreover, the comprehension and suitability of each question were rated as excellent (Pearson's correlation coefficient = 0.3).

Conclusions

Our findings revealed that the Farsi translation of the HDSS and SHS-HD can be a valuable tool for evaluating the symptom severity in patients with hemorrhoid disease.

Predictors of outcome in cryptoglandular anal fistula according to magnetic resonance imaging: A systematic review

Background and Aims

Anal fistula (AF) with cryptoglandular origin tends to recur, and multiple risk factors are implicated. Recently, some magnetic resonance imaging (MRI) findings with predictive value for disease outcomes have been proposed. These intrinsic anatomic features include those of the AF and its surrounding structures. This study aims to clarify the prognostic role of MRI in AF.

Methods

We performed a systematic search of PubMed, Embase, and EBSCO databases. Two independent reviewers conducted the search and screened the articles. We selected studies that used MRI to assess AF and reported its relationship to disease outcome. We extracted data regarding the study design, type of intervention, outcome, MRI-measured items, and their significance.

Results

Out of 1230 retrieved articles, 18 were eligible for final inclusion, and a total of 4026 patients were enrolled in the selected studies. For preoperative MRI, the significant items affecting the outcome were the length of the fistula, horseshoe type, presence of multiple tracts, supralevator extension, and apparent diffusion coefficient (ADC) value. Other studies investigated the healing process using postoperative MRI.

Conclusion

This review found that MRI can be useful in the management of AF, both preoperatively and postoperatively. Factors, such as fistula length, horseshoe type, presence of multiple tracts, supralevator extension, and ADC value were found to be significantly associated with treatment outcomes. The presence of the fistula tract and the development of new abscesses on postoperative MRI was found to hinder the healing process. Further studies are needed to confirm these findings.

Hand-sewn direct repair versus resection and hand-sewn anastomosis techniques for the reversal of diverting loop ileostomy after lower anterior rectal resection surgery: A randomized clinical trial

INTRODUCTION

Several techniques have been proposed for the closure of loop ileostomy. This is the first study comparing bowel function and outcomes of two different hand-sewn surgical techniques used for the closure of diverting protective loop ileostomy.

METHOD

In this prospective, randomized, double-blind clinical trial, 40 patients with a history of rectal cancer, low anterior resection, and diverting loop ileostomy who were candidates for ileostomy reversal were included and randomly assigned into two groups, hand-sewn direct repair of the ileal defect (group A) and resection and hand-sewn anastomosis of the ileum (group B).

RESULTS

The mean age of patients was 56.42 and 52.10 years in groups A and B, respectively. Regarding early postoperative period, group A developed earlier first gas passage (1.68 vs. 2.25 days, p = 0.041) and stool passage (2.10 vs. 2.80 days, p = 0.032). Group A also revealed shorter operating time (83.68 vs. 89.50 min, p = 0.040) and hospital stay (4.73 vs. 6.80 days, p = 0.001). None of the participants in both groups developed signs of bowel obstruction during the early and late postoperative follow-up period.

CONCLUSIONS

Direct hand-sewn repair for the closure of diverting loop ileostomy is a safe technique with better postoperative bowel function, oral diet tolerance, and less hospital stay compared to resection and hand-sewn anastomosis of the ileum.

Safety and efficacy of injection of human placenta mesenchymal stem cells derived exosomes for treatment of complex perianal fistula in non-Crohn's cases: Clinical trial phase I

BACKGROUND AND AIM

A perianal fistula is an abnormal tract that connects anal canal to skin. Current medical and surgical interventions have a high failure rate particularly in complex and refractory cases. MSC-derived exosomes have demonstrated immunomodulatory effects without the conventional complications; hence, in this study, we evaluated the safety of their application for complex perianal fistula.

METHODS

Placenta-derived MSCs were cultured, and exosomes were isolated using ultracentrifugation. Exosome injections were administered in the operating room to 11 patients with complex perianal fistula (presence of fistulas for at least 1 year alongside medical and surgical treatment). The patients were followed for 6 months, and the patients were evaluated using physical examination, face-to-face interviews, and magnetic resonance imaging (MRI).

RESULTS

Among 11 patients only one did not show any improvement upon physical examination. Five patients showed complete tract resolve. While the discharge was stopped in eight patients, two patients showed only reduction. None of the patients showed any acute or latent allergic reaction or injection related complications.

CONCLUSION

Administration of exosomes isolated from MSCs demonstrates safety and a satisfactory therapeutic effect in treatment complex perianal fistulae; therefore, it can be a candidate for future studies and might play a significant role in treatment.

Biomedical properties and hemostatic efficacy of polyvinyl alcohol (PVA) based hydrogel in experimental rat liver injury model

PURPOSE

Bleeding is a leading cause of mortality and morbidity in the trauma and surgery field, using effective hemostatic agents can help us reduce bleeding especially in parenchymal hemorrhage. Nowadays polyvinyl alcohol (PVA) is known as a safe candidate for wound dressing and maybe a hemostatic agent. PVA-based hydrogel is a popular biocompatible material in the biomedical field especially when it has high water absorption. In this study, we investigated the PVA hydrogel's mechanical and biological properties as well as its hemostatic potential in parenchymal bleeding.

METHODS

PVA hydrogel had made by the freeze-thawing approach, we used PVA hydrogel in comparison to standard treatment to investigate hemostatic potency. Also, we performed MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) tests to survey PVA cellular toxicity. After an acute liver injury, two groups of 12 rats were treated with PVA hydrogel or standard treatment with sterile gauze. The results including the time and volume of bleeding, and the time and survival rate of the rats were measured and compared.

RESULTS

We saw that PVA hydrogel was safe with no cellular toxicity in the MTT assay. Regarding efficacy, PVA hydrogel increased rats' survival after bleeding from 75% to 91.7%, and decreased bleeding time (p: 0.015), and bleeding volume (p: 0.03) compared to the control group.

CONCLUSION

Polyvinyl alcohol is safe. It has good biological properties with no cellular toxicity and has a significant hemostatic effect and can be regarded in control of parenchymal hemorrhage.

Surgical management of a solitary metastatic ovarian adenocarcinoma with colonic origin presenting as gigantic bilateral ovarian masses

Metastatic ovarian tumors with a gastrointestinal origin have always been a challenge in surgery; in many cases, the primary tumor is diagnosed after the metastasis. This case was presented with bilateral abdominal masses, which were adenocarcinomas originating from gastrointestinal tract. Following colonoscopy and finding a mass, total colectomy was performed.

The key clinical message, in this case, is that large, bilateral masses in the absence of ascites are suggestive for an extragonadal origin for which one of the primary sources is GI, so endoscopy and colonoscopy should be carried out for these patients (for gastric and colonic cancers). Resecting the primary tumor with metastasis is controversial, and not currently enough data are available. Our assumption is that we have to rule out the secondary sites of metastasis and peritoneal seeding, for which palliative chemotherapy and ostomy diversion for obstructive cases is the only option. In cases with no secondary site of metastasis surgery is considered an option, but the risk of metachronous metastasis is high, and the prognosis is poor.

Evaluating the safety and efficacy of mesenchymal stem cell-derived exosomes for treatment of refractory perianal fistula in IBD patients: clinical trial phase I

Background

Exosome administration is a novel medical approach that promises excellent immunomodulatory properties without the conventional side effects of current antitumor necrosis factor drugs and stem cells. This study aimed to assess the safety and efficacy of using mesenchymal stem cell (MSC) exosomes to treat refractory fistulas in patients with inflammatory bowel disease.

Methods

MSCs were derived from the umbilical cords and their exosomes were isolated. Five patients with refractory perianal Crohn’s disease fistulas with a median age of 35 years (range 31–47 years) were enrolled in the study. Exosome injections were administered in the operating room to patients with refractory fistula (fistulas that are irresponsive to anti-tumor necrosis factor-α administration within 6 months). Six months later, a physical examination, face-to-face interviews, and magnetic resonance imaging were employed to evaluate the therapy responses of patients.

Results

The outcomes within 6 months after initiation of therapy showed that four patients had responded to therapy. Three patients who received exosome injections exhibited complete healing, while one reported no improvement and active discharge from the fistula site. In addition, five patients (100%) reported neither systemic nor local adverse effects.

Conclusions

Injection of exosomes extracted from MSCs demonstrates safety and a satisfactory therapeutic effect, as evidenced in this and other studies, and may play a significant role in the future treatment of gastrointestinal fistulas.

Advanced Regenerative Medicine Strategies for Treatment of Perianal Fistula in Crohn's Disease

Regenerative medicine is an emerging therapeutic method that aims to reconstruct tissues and organs. This advanced therapeutic approach has demonstrated great potential in addressing the limitations of medical and surgical procedures for treating perineal fistula in patients with Crohn's disease. Recent developments in stem cell technology have led to a massive good manufacturing practices (GMPs) production of various stem cells, including mesenchymal and embryonic cells, along with induction of pluripotent stem cells to repair damaged tissues in the fistula. The recent advances in separation and purification of exosomes, as biologic nanovesicles carrying anti-inflammatory and regenerative agents, have made them powerful tools to treat this inflammatory disease. Further, tremendous advances in nanotechnology, biomaterials, and scaffold fabrication methods enable tissue engineering methods to synthesize tissue-like structures to assist surgical techniques. This review focuses on advanced regenerative-based methods including stem cell therapy, exosome therapy, and tissue engineering used in the treatment of perianal fistula. Relevant in vitro and in vivo studies and the latest innovations in implementation of regenerative medicine for this disease are also separately reviewed. Additionally, current challenges regarding implementation of g stem cells, exosomes, and tissue engineering methods for bridging the gaps between laboratory findings and clinic application will be discussed.

Microfluidic-Based Droplets for Advanced Regenerative Medicine: Current Challenges and Future Trends

Microfluidics is a promising approach for the facile and large-scale fabrication of monodispersed droplets for various applications in biomedicine. This technology has demonstrated great potential to address the limitations of regenerative medicine. Microfluidics provides safe, accurate, reliable, and cost-effective methods for encapsulating different stem cells, gametes, biomaterials, biomolecules, reagents, genes, and nanoparticles inside picoliter-sized droplets or droplet-derived microgels for different applications. Moreover, microenvironments made using such droplets can mimic niches of stem cells for cell therapy purposes, simulate native extracellular matrix (ECM) for tissue engineering applications, and remove challenges in cell encapsulation and three-dimensional (3D) culture methods. The fabrication of droplets using microfluidics also provides controllable microenvironments for manipulating gametes, fertilization, and embryo cultures for reproductive medicine. This review focuses on the relevant studies, and the latest progress in applying droplets in stem cell therapy, tissue engineering, reproductive biology, and gene therapy are separately evaluated. In the end, we discuss the challenges ahead in the field of microfluidics-based droplets for advanced regenerative medicine.

Splenic flexure volvulus, a rare etiology of colonic obstruction: Case report

Introduction

Splenic flexure volvulus (SFV) occurs as a result of twisting or torsion of a redundant colon around its mesentery. The SFV can be divided into primary and secondary types.

Presentation of case

An 82-year-old woman with a previous history of Parkinson's disease, diabetes mellitus and hypertension presented with a primary complaimt of obstipation and progressive abdominal pain. Abdomen was grossly distended and tympanic with generalized tenderness. The rectum was empty on digital rectal examination. Complete blood count showed leuckocytosis and neutrophlia. Plain abdominal X-rays showed distented cecum and ascending colon without any air in the gut distal to the splenic flexure. Regarding her unstable condition even aftre fluid resuscitation, she was transferred to the operating room. SFV was found and the standard left hemicolectomy was performed and bowel continiuity was established with primary anastomis of remained colonic ends. Postoperative period was uneventfull.

Discussion

The splenic flexure is strictly attached to the adjacent organs so its volvulus is rare. Most cases of adult SFV have an underlying disease associated with chronic constipation. Diagnosis of volvulus is suspected based on the history, clinical exam, and imaging. The initial and urgent treatment of SFV, if there are no signs of ischemia or perforation, may be conservative with endoscopic detorsion. Gangrenous bowel should not be detorted and should be resected with primary anastomosis or a diverting stoma.

Conclusion

SFV should be considered as a possible diagnosis of chronic constipation which might be diagnosed with plain abdominal Xray in non emergent condition. Special attention should be given to the medication history of the patient as the anticholinergic agents propagate normal pristaltis.

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Splenic flexure volvulus (SFV) is a rare condition of colonic obstruction

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An 82-year-old bedridden woman with a previous history of parkinson’s disease presented to the emergency department.

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SFV was seen due to the absence of leno-colic and phreno-colic ligaments and the proximal descending colon was intraperitoneal.

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An interesting finding about psychological profile of patients with SFV is that nearly all of these patients have a history of taking antipsychotic medication.

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The medication history of drugs interfering with gastrointestinal motility can be a guide for timely diagnosis.

Introduction of a Handmade Vacuum-Assisted Sponge Drain for the Treatment of Anastomotic Leakage After Low Anterior Rectal Resection

Purpose

Anastomotic leakage, a known major postoperative complication, potentially leads to readmission, reoperation, and increased mortality rates in patients, such as rectal cancer patients following a low anterior resection (LAR). Currently, vacuum-assisted closure, as featured by B-Braun (B-Braun Medical B.V.), is already being used for the treatment of gastrointestinal leakages and fistulas. The main aim of this study was to introduce a novel method for creating a vacuum-assisted drain for the treatment of anastomotic leakage after LAR.

Methods

All 10 patients, who underwent LAR surgery from 2018 to 2019, were diagnosed with anastomotic leakage and had received neoadjuvant chemotherapy prior to surgery. Therefore, patients were treated with a handmade vacuum-assisted drain and were revisited every 5 to 7 days for further evaluations and drain replacement until leakage resolution. Physical features of cavity, time of diagnose, and duration of treatment were analyzed correspondingly. The handmade vacuum-assisted sponge drain was prepared for each patient in each session of follow-up.

Results

Eight out of 10 patients experienced complete closure of the defect. The mean delay time from the day of operation to the diagnosis of anastomotic leakage was 61.0±80.4 days while the mean time for leakage closure was 117.6±68.3 days. Eventually, 7 cases underwent ileostomy reversal with no complications during a 3-month follow-up.

Conclusion

In this study, we evaluated the healing process of anastomotic leakage after the usage of a handmade vacuum-assisted sponge drain in a case series method. In our trial, we provided an innovative cost-benefit method easily applicable in the operating room.

Primary rectal choriocarcinoma associated with rectal adenocarcinoma in a woman with a history of ulcerative colitis: Case report

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Gestational Throphoblastic Neoplasms (GTN) includes a spectrum of pregnancy-related disorders of either benign or malignant.

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Gestational choriocarcinoma in a patient with a previous history of IBD could have occurred in three different scenarios.

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Dedifferentiation is the most accepted mechanism introduced to explain development of primary choriocarcinoma of colorectal origin.

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Surgical resection with lymph node dissection is the standard of treatment.

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Colorectal choriocarcinoma is considered pathologically similar to choriocacinoma of GTN, thus chemotherapeutic regimens are the same.

Introduction

Primary rectal choriocarcinoma is an extremely rare malignancy. The association of these neoplasms in patients with inflammatory bowel disease (IBD) has not been reported.

Presentation of case

A 34-year-old female with history of Ulcerative Colitis (UC) gave birth to a male fetus. She had postpartum bleeding and high level of beta-human chorionic gonadotropin (βhCG) was detected. Although initial investigations failed to confirm molar pregnancy, abnormal uterine bleeding and high βhCG level necessitate chemotherapy administration. She did not respond to chemotherapy sessions accordingly. Meanwhile, the patient experienced rectorrhagia and colonoscopy revealed a firm submucosal polypoid lesion 8–10 cm from the anal verge. The multidisciplinary team candidate the patient for total proctocolectomy and ileal pouch anal anastomosis. Although postoperative course was uneventful and βhCG level dropped but it showed a rising pattern in follow ups. Chemotherapy was planned but there was not suitable response. Unfortunately, the patient passed away 20 months after the initial diagnosis.

Discussion

Pathology report indicated the coexistence of moderately differentiated tubular adenocarcinoma and choriocarcinoma. We assume previous history of UC might have put her at higher susceptibility to develop carcinoma and this poorly differentiated carcinoma has led to choriocarcinoma. Considering the fact that in most cases of colorectal choriocarcinoma, choriocarcinomatous differentiation was found alongside colonic adenocarcinoma made dedifferentiation theory to be the most acceptable explanation.

Conclusion

The adenocarcinoma of the colon and rectum in the setting of IBD may become so dedifferentiated that gain some characteristics of germ cell tumors.