Rapamycin, but not cyclosporine A, inhibits vascularization and incorporation of implanted surgical meshes

Immunoprotection of cellular transplants for autoimmune type 1 diabetes through local drug delivery

Type 1 diabetes mellitus (T1DM) is an autoimmune condition that results in the destruction of insulin-secreting β cells of the islets of Langerhans. Allogeneic islet transplantation could be a successful treatment for T1DM; however, it is limited by the need for effective, permanent immunosuppression to prevent graft rejection. Upon transplantation, islets are rejected through non-specific, alloantigen specific, and recurring autoimmune pathways. Immunosuppressive agents used for islet transplantation are generally successful in inhibiting alloantigen rejection, but they are suboptimal in hindering non-specific and autoimmune pathways. In this review, we summarize the challenges with cellular immunological rejection and therapeutics used for islet transplantation. We highlight agents that target these three immune rejection pathways and how to package them for controlled, local delivery via biomaterials. Exploring macro-, micro-, and nano-scale immunomodulatory biomaterial platforms, we summarize their advantages, challenges, and future directions. We hypothesize that understanding their key features will help identify effective platforms to prevent islet graft rejection. Outcomes can further be translated to other cellular therapies beyond T1DM.

Polypropylene mesh combined with electrospun poly (L-lactic acid) membrane in situ releasing sirolimus and its anti-adhesion efficiency in rat hernia repair

This study developed, a novel polypropylene (PP) mesh combined with poly (L-lactic acid) (PLA) electrospun nanofibers loaded sirolimus (SRL). The PP mesh was combined with PLA/SRL (1/0, 1/0.01, 1/0.02; mass ratios) composed electrospun membrane characterized by FTIR spectroscopy, XPS and SEM, and evaluated for cytocompatibility in vitro. In an in vivo study, a total of 84 Sprague-Dawley rats were employed to evaluate the efficacy of the novel composite PP mesh anti-adhesion, mechanical properties and inflammation. As a results, the PLA/SRL membrane could compound with PP mesh stably and load SRL. Although tensile testing showed that the mechanical properties of composite mesh decreased in vivo, the integration strength between the tissue and mesh was still able to counteract intra-abdominal pressure. Compared with the native PP mesh group, the novel PP mesh group showed a lower score for abdominal adhesion and inflammation. More importantly, the novel PP mesh completely integrated with the abdominal wall and had sufficient mechanical strength to repair abdominal wall defects.

Abdominal wall complications after kidney transplantation: A clinical review

Introduction

Abdominal wall complications are common after kidney transplantation, and although they have a minor impact on patient and graft survival, they increase the patient's morbidity and may have an impact on quality of life. Abdominal wall complications have an overall incidence of 7.7–21%.

Methods

This review will explore the natural history of abdominal wall complications in the kidney transplant setting, with a special focus on wound dehiscence and incisional herni, with a particular emphasis on risk factors, clinical characteristics, and treatment.

Results

Many patient‐related risk factors have been suggested, including older age, obesity, and smoking, but kidney transplant recipients have an additional risk related to the use of immunosuppression. Wound dehiscence usually does not require surgical intervention. However, for deep dehiscence involving the fascial layer with concomitant infection, surgical treatment and/or negative pressure wound therapy may be required.

Conclusions

Incisional hernia (IH) may affect 1.1–18% of kidney transplant recipients. Most patients require surgical treatment, either open or laparoscopic. Mesh repair is considered the gold standard for the treatment of IH, since it is associated with a low rate of postoperative complications and an acceptable rate of recurrence. Biologic mesh could be an attractive alternative in patients with graft exposition or infection.

Hernia and Cancer: The Points Where the Roads Intersect

Introduction: This review aimed to present common points, intersections, and potential interactions or mutual effects for hernia and cancer. Besides direct relationships, indirect connections, and possible involvements were searched. Materials and Methods: A literature search of PubMed database was performed in July 2018 as well as a search of relevant journals and reference lists. The total number of screened articles was 1,422. Some articles were found in multiple different searches. A last PubMed search was performed during manuscript writing in December 2018 to update the knowledge. Eventually 427 articles with full text were evaluated, and 264 included, in this review. Results: There is no real evidence for a possible common etiology for abdominal wall hernias and any cancer type. The two different diseases had been found to have some common points in the studies on genes, integrins, and biomarkers, however, to date no meaningful relationship has been identified between these points. There is also some, albeit rather conflicting, evidence for inguinal hernia being a possible risk factor for testicular cancer. Neoadjuvant or adjuvant therapeutic modalities like chemotherapy and radiotherapy may cause postoperative herniation with their adverse effects on tissue repair. Certain specific substances like bevacizumab may cause more serious complications and interfere with hernia repair. There are only two articles in PubMed directly related to the topic of "hernia and cancer." In one of these the authors claimed that there was no association between cancer development and hernia repair with mesh. The other article reported two cases of squamous-cell carcinoma developed secondary to longstanding mesh infections. Conclusion: As expected, the relationship between abdominal wall hernias and cancer is weak. Hernia repair with mesh does not cause cancer, there is only one case report on cancer development following a longstanding prosthetic material infections. However, there are some intersection points between these two disease groups which are worthy of research in the future.

Laparoscopic Repair of Boundary Incisional Hernia in a Kidney Transplant Patient: A Safe Tacks-Fibrin Glue Combined Mesh Fixation Technique

BACKGROUND

Incisional hernia in renal transplant patients is a complication that negatively affects the global outcome of transplant and quality of life. The repair of this condition was classically made by open repair with mesh. Increasing evidence suggests that laparoscopic repair could be advocated as the technique of choice in these patients with optimal results. However, the fixation of mesh should be performed by a mixed combination of fibrin sealant (lateral margin of wall defect) and tacks (medial margin). The tacks fixation of the mesh along the lateral margin of the wall defect, close to the graft, is generally difficult for the small size of the remaining aponeurotic plane and dangerous for the underlying presence of the graft.

MATERIALS AND METHODS

A case of incisional hernia in a kidney transplant recipient was repaired by laparoscopic mesh technique. The polypropylene-polyglycolic acid composite mesh was fastened with a mixed technique of absorbable tacks for medial margin of the defect and fibrin sealant for the lateral side in contiguity with graft surface.

RESULTS

The patient was discharged after 4 days. The 6-month follow-up did not show mesh displacement or recurrence of hernia.

CONCLUSIONS

The laparoscopic mesh repair may become the criterion standard for kidney transplant patients affected by incisional hernia. The difficulties of mesh fixation close to the graft can be overcome by the combination of fibrin sealant glue and absorbable tacks at different margins of the wall defect. This technique may offer advantages for this population of patients.

Sirolimus-coated, poly(L-lactic acid)-modified polypropylene mesh with minimal intra-peritoneal adhesion formation in a rat model

PURPOSE

This study evaluated the manufacturing method and anti-adhesion properties of a new composite mesh in the rat model, which was made from sirolimus (SRL) grafts on a poly(L-lactic acid) (PLLA)-modified polypropylene (PP) hernia mesh.

METHODS

PLLA was first grafted onto argon-plasma-treated native PP mesh through catalysis of stannous chloride. SRL was grafted onto the surface of PP-PLLA meshes using catalysis of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 4-dimethylaminopyridine (DMAP) in a CH₂Cl₂ solvent. Sprague-Dawley female rats received either SRL-coated meshes, PP-PLLA meshes, or native PP meshes to repair abdominal wall defects. At different intervals, rats were euthanized by a lethal dose of chloral hydrate and adhesion area and tenacity were evaluated. Sections of the mesh with adjacent tissues were assessed histologically.

RESULTS

Attenuated total reflection Fourier transformed infrared (ATR-FTIR) spectroscopy indicated the existence of a C=O group absorption peak (1724.1 cm^-1), and scanning electron microscope morphological analysis indicated that the surface of the PP mesh was covered with SRL. Compared to the native PP meshes and PP-PLLA meshes, SRL-coated meshes demonstrated the greatest ability to decrease the formation of adhesions (P < 0.05) and inflammation.

CONCLUSIONS

The SRL-coated composite mesh showed minimal formation of intra-abdominal adhesions in a rat model of abdominal wall defect repair.

Laparoscopic Repair of Incisional Hernia Following Liver Transplantation-Early Experience of a Single Institution in Taiwan

BACKGROUND

Ventral incisional hernia (VIH) is not uncommon following liver transplantation. Open repair was traditionally adopted for its management. Laparoscopic repair of VIH has been performed successfully in nontransplant patients with evidence of reduced recurrence rates and hospital stay. However, the application of VIH in post-transplantation patients has not been well established. Herein, we provide our initial experience with laparoscopic repair of post-transplantation VIH.

METHODS

From March 2015 to March 2016, 18 cases of post-transplantation VIH were subjected to laparoscopic repair (laparoscopy group). A historical control group of 17 patients who underwent conventional open repair (open group) from January 2013 to January 2015 were identified for comparison. The demographics and clinical outcomes were retrospectively compared.

RESULTS

There were no significant differences among basic demographics between the 2 groups. No conversion was recorded in the laparoscopy group. Recurrence of VIH up to the end of the study period was not noted. In the laparoscopy group, the minor complications were lower (16.7% vs 52.9%; P = .035), the length of hospital stay was shorter (3 d vs 7 d, P = .007), but the median operative time was longer (137.5 min vs 106 min; P = .003).

CONCLUSIONS

Laparoscopic repair of post-transplantation VIH is a safe and feasible procedure with shorter length of hospital stay.

No Effect of Rapamycin on Cardiac Adhesion Formation: A Drug-Loaded Bioresorbable Polylactone Patch in a Porcine Cardiac Surgical Model

Background: The fusing of the epicardium and sternum due to adhesion is a common problem during repeated cardiac surgery and carries with it an increased risk of bleeding. The use of barriers and patches has been tested to prevent the formation of adhesions, but the very presence of a patch can provoke adhesion formation. The objective of this study was, therefore, to investigate both biodegradable and bioresorbable polylactone patches [(polycaprolactone-poly(ethylene oxide)-polycaprolactone tri-block copolymer (PCE)]. The patches were also tested with a controlled release of rapamycin, which prevents cell migration and extracellular matrix deposition. The clinical effectiveness of rapamycin in pericardial patches has not previously been examined. Materials and Methods: Three groups of 6 female Danish Landrace pigs underwent sternotomy and abrasion of the epicardium, before being randomized to either group 1 - the control group (with no patch), group 2 - PCE patch implanted between the sternum and epicardium, or group 3 - PCE patch and slow-release 1.6-mg rapamycin. After a median time period of 26 days, the pigs were euthanized and their hearts removed en bloc with the sternum, for macroscopic, histological and pathological examination. Results: Upon macroscopic examination, a significantly lower degree of adhesion in group 2, as compared to group 1 (p < 0.05), was found. Histological analysis of the tissues showed significantly more fibrosis, inflammation and foreign body granulomas (p < 0.05) in both group 2 and group 3, when compared to group 1. Conclusion: A PCE patch following sternotomy in animal subjects reduces postoperative macroscopic adhesions without reducing microscopic fibrosis or inflammation. Loading the patch with rapamycin was found not to increase the antifibrotic effect.

Abdominal wall defect repair with biological prosthesis in transplanted patients: single center retrospective analysis and review of the literature

The risk of fascial dehiscence, wound infection and incisional hernias in organ recipients is higher. Retrospective analysis of our departments database, checking the last 12 years (2000-2012), and of the literature (1966-2012) were conducted. In our database we found seven patients: five liver (71.4 %), one kidney (14.3 %), one multivisceral (14.3 %); five males (71.4 %), two females (28.6 %). Five (71.4 %) were operated in urgency setting and two in ordinary setting (28.6 %). The mean/median number of laparotomies before the incisional hernia is of 2.1/1 (range 1-5). In five patients swine intestinal submucosa (71.4 %) have been used and in two porcine dermal collagen (28.6 %). The mean/median age was 48.3/52 years (range 18-61). The mean/median body mass index was 26.7/27 (range 19-34). The mean/median for follow-up after intervention was 40.1/33 months (range 50-21). Recurrence rate was 14.3 %. Complication rate was 28.6 %. Adding the present report, the literature reports 70 cases. 20 % of prosthesis have been implanted inlay, 25.7 % underlay, in 5.7 % intraperitoneal and in 48.6 % were not specified. The mean age ranges from 0.7 to 48.3 years. Kidney, liver, pancreas, bowel and multivisceral transplant are reported. Porcine dermal collagen has been implanted in 24.3 %, human dermal collagen in 51.4 % and swine intestinal submucosa in 24.3 %. The immunosuppression regimens comprehend variable associations of tacrolimus, steroids, mycophenolate mofetil, sirolimus, thymoglobulin, azathioprine/basiliximab and daclizumab. The mean follow-up is 16.2 months. The mean complication rate is 9.4 %. Biological prosthesis seems to be useful and safe in abdominal wall repair surgery in transplanted patients.

Early use of mammalian target of rapamycin inhibitors is an independent risk factor for incisional hernia development after liver transplantation

Incisional hernias (IHs) are common complications after liver transplantation (LT) with a reported incidence of 1.7% to 34.3%. The purpose of this retrospective study was to evaluate the risk factors for IH development after LT with a focus on the role of immunosuppressive therapy during the first month after LT. We analyzed 373 patients who underwent LT and divided them into 2 groups according to their postoperative course: an IH group (121 patients or 32.4%) and a no-IH group (252 patients or 67.6%). A univariate analysis demonstrated that the following were risk factors related to IH development: male sex (P = 0.03), a body mass index ≥ 29 kg/m(2) (P = 0.005), LT after 2004 (P = 0.02), a Model for End-Stage Liver Disease (MELD) score ≥ 22 (P = 0.01), and hepatitis B virus infection (P = 0.01). The highest incidence of IHs was found in patients treated with mammalian target of rapamycin (mTOR) inhibitors (54.5%, P = 0.004). A multivariate analysis revealed male sex (P = 0.03), a pretransplant MELD score ≥ 22 (P = 0.04), and the use of mTOR inhibitors (P = 0.001) to be independent risk factors for IHs after LT. In conclusion, immunosuppressive therapy with mTOR inhibitors is an important independent risk factor for IH development after LT. To reduce the incidence of IHs, mTOR inhibitors should be avoided until the fourth month after LT unless their use is deemed to be strictly necessary.

Incisional hernia after simultaneous pancreas kidney tranplantation: a single-center experience from Budapest

INTRODUCTION

The occurrence of postoperative incisional hernia is more frequent after simultaneous pancreas-kidney transplantation compared with other transplanted parenchymal organs. These complications are especially dangerous in this patient population, because they can compromise the survival of the transplanted organ.

METHODS

We performed a retrospective review of a series of adult patients with incisional herniae after 23 consecutive simultaneous pancreas-kidney transplantations between January 2004 and June 2010 seeking to identify risk factors. All 23 patients had a body mass index (BMI) of <25. All surgeons used a similar technique, including a median incision with an intraperitoneal approach, and systemic venous and enteric drainage methods and a layered fascial closure. All combined pancreas-kidney transplant recipients received induction with thymoglobulin and maintenance therapy with sirolimus, reduced-dose cyclosporine and corticosteroids.

RESULTS

An incisional hernia repair was performed in 8/23 patients (34.8%). Four reoperations were required in this group (50%), due to hemoperitoneum (n=2), intra-abdominal abscess (n=1), and venous thrombosis (n=1). The mean elapsed time between transplantation and hernioplasty was 24.5 months (range, 8-51). There was no significant difference in age, gender, BMI, dialysis modality, or operative time among affected compared with the other members of the group.

CONCLUSION

Despite lack of obesity we observed a relatively higher rate of postoperative herniase, possibly owing to the side effects of a thymoglobulin-sirolimus combination.

Blockade of gC1qR/p33, a receptor for C1q, inhibits adherence of Staphylococcus aureus to the microvascular endothelium

Endovascular infections with Staphylococcus aureus (S. aureus) are associated with high mortality. gC1qR/p33 (gC1qR), a receptor for the complement component C1q expressed on endothelial cells, interacts with protein A of S. aureus and gC1qR blockade reduces S. aureus colonization during infective endocarditis. The aim of this study was to analyze in vivo whether this observation is due to a decreased interaction of S. aureus with the microvascular endothelium. A dorsal skinfold chamber was prepared in Syrian golden hamsters, which were treated with the monoclonal antibody (MAb) 74.5.2 directed against gC1qR or vehicle. The interaction of fluorescein isothiocyanate (FITC)-labeled staphylococci and leukocytes with the endothelium was analyzed under physiological conditions as well as after TNF-α-induced inflammation using intravital fluorescence microscopy. Administration of MAb 74.5.2 significantly reduced adherence of S. aureus to the endothelium in untreated and TNF-α-exposed tissue. In addition, we could demonstrate in vitro that S. aureus adherence to human endothelial cells was inhibited by MAb 74.5.2. Blockade of gC1qR did not affect leukocyte-endothelial cell interaction. In conclusion, our findings indicate that immunological inhibition of gC1qR may be therapeutically used to decrease the interaction of S. aureus with the microvascular endothelium.

How to detect a dwarf: in vivo imaging of nanoparticles in the lung

Nanotechnology is a rapidly developing field in science and industry. The exposure to nanoparticles (NPs) will steadily grow in the future and there is thus an urgent need to study potential impacts of the interaction between NPs and the human body. The respiratory tract is the route of entry for all accidentally inhaled NPs. Moreover, NPs may intentionally be delivered into the lung as contrast agents and drug delivery systems. The present review provides an overview of currently used techniques for the in vivo imaging of NPs in the lung, including x-ray imaging, computed tomography, gamma camera imaging, positron emission tomography, magnetic resonance imaging, near-infrared imaging, and intravital fluorescence microscopy. Studies based on these techniques may contribute to the development of novel NP-based drug delivery systems and contrast agents. In addition, they may provide completely new insights into nanotoxicological processes.

FROM THE CLINICAL EDITOR

Nanoparticles are rapidly gaining ground in various therapeutic and diagnostic applications. This review provides an overview of current in vivo imaging techniques of NPs in the lung, including x-ray, CT, gamma camera imaging, PET, MRI, near-infrared imaging, and intravital fluorescence microscopy, aiding the development of novel NP-based techniques and nanotoxicology.

Experience of laparoscopic incisional hernia repair in kidney and/or pancreas transplant recipients

Despite the wide popularity of laparoscopic incisional hernia repair (LIHR) in the nontransplant population, there are very few reports of LIHR available in abdominal organ transplant patients and none exclusively on kidney and/or pancreas (KP) transplant patients. We retrospectively reviewed a consecutive series of LIHR in KP transplant recipients performed over a period of 4 years and compared the results with LIHR in non-transplant patients during the same period. A total of 36 transplant patients were compared with 62 nontransplant patients. There were five patients converted to the open procedure in the transplant and four in nontransplant patients (p-NS). There were three seromas and one patient had a bowel perforation in the transplant group versus eight seromas, one bowel perforation and one small bowel obstruction noted in the nontransplant group. One patient in each group had a mesh infection requiring explant. Patients were followed up for a mean period of 2.2 years in the transplant group and 3 years in the nontransplant group. Overall there were five recurrences in the transplant group and four in the nontransplant group (p = NS). These results suggest that that LIHR is a safe and effective alternative to open repair.