The Inhibitory Effects of Naringin in a Rat Model of Postoperative Intraperitoneal Adhesion Formation

Background. Many attempts have been made to inhibit the formation of postoperative intraperitoneal adhesions, but the results have been discouraging. Therefore, the identification of effective preventative measures or treatments is of great importance. In this study, the substantial potential of naringin (NG) to reduce peritoneal adhesions was validated in a rat model. Materials and Methods. A rat peritoneal adhesion model was established by abrasion of the cecum and its opposite intraperitoneal region under aseptic surgical conditions. After the operation, three groups of NG-treated rats were given 2 mL of NG by gavage at different concentrations (40, 60, or 80 mg/kg/d). The sham, control, and hyaluronan (HA) groups were given equal volumes of normal saline daily. On the 8th day, all rats were sacrificed 30 min after the administration of an activated carbon solution (10 mL/kg) by oral gavage. Intraperitoneal adhesion formation was adequately evaluated by necropsy, hematoxylin and eosin (HE) staining, Sirius red staining, immunofluorescence staining, enzyme-linked immunosorbent assays, and reactive oxygen species (ROS) probes. The gastrointestinal dynamics of the rats were assessed on the basis of a small intestinal charcoal powder propulsion test and the detection of motilin and gastrin levels in serum. Results. Intraperitoneal adhesions were markedly reduced in the group of rats receiving high-dose NG. Compared with the control group, the high-dose NG group showed clear reductions in inflammatory reactions, oxidative stress, collagen deposition, and fibroblast formation in the adhesion tissue and enhanced gastrointestinal dynamics ( P < 0.05). Conclusion. NG alleviated the severity of intraperitoneal adhesions in a rat model by reducing inflammation, oxidative stress, collagen deposition, and fibroblast formation, highlighting the potential of NG as a drug candidate to prevent postoperative peritoneal adhesion formation.

Adipocyte-specific deletion of PIP5K1c reduces diet-induced obesity and insulin resistance by increasing energy expenditure

Background Phosphatidylinositol 4-phosphate 5-kinase type I c (PIP5K1c) catalyses the synthesis of phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) by phosphorylating phosphatidylinositol 4 phosphate, which plays multiple roles in regulating focal adhesion formation, invasion, and cell migration signal transduction cascades. Here, a new physiological mechanism of PIP5K1c in adipocytes and systemic metabolism is reported. Methods Adipose-specific conditional knockout mice were generated to delete the PIP5K1c gene in adipocytes. In addition, in vitro research investigated the effect of PIP5K1c deletion on adipogenesis. Results Deletion of PIP5K1c in adipocytes significantly alleviated high fat diet (HFD)-induced obesity, hyperlipidaemia, hepatic steatosis, and insulin resistance. PIP5K1c deficiency in adipocytes also decreased adipocyte volume in HFD-induced obese mice, whereas no significant differences were observed in body weight and adipose tissue weight under normal chow diet conditions. PIP5K1c knockout in adipocytes significantly enhanced energy expenditure, which protected mice from HFD-induced weight gain. In addition, adipogenesis was markedly impaired in mouse stromal vascular fraction (SVF) from PIP5K1c-deleted mice. Conclusion Under HFD conditions, PIP5K1c regulates adipogenesis and adipose tissue homeostasis. Together, these data indicate that PIP5K1c could be a novel potential target for regulating fat accumulation, which could provide novel insight into the treatment of obesity.

A Systematic Review Examining the Experimental Methodology Behind In Vivo Testing of Hiatus Hernia and Diaphragmatic Hernia Mesh

Introduction Mesh implants are regularly used to help repair both hiatus hernias (HH) and diaphragmatic hernias (DH). In vivo studies are used to test not only mesh safety, but increasingly comparative efficacy. Our work examines the field of in vivo mesh testing for HH and DH models to establish current practices and standards. Method This systematic review was registered with PROSPERO. Medline and Embase databases were searched for relevant in vivo studies. Forty-four articles were identified and underwent abstract review, where 22 were excluded. Four further studies were excluded after full-text review—leaving 18 to undergo data extraction. Results Of 18 studies identified, 9 used an in vivo HH model and 9 a DH model. Five studies undertook mechanical testing on tissue samples—all uniaxial in nature. Testing strip widths ranged from 1–20 mm (median 3 mm). Testing speeds varied from 1.5–60 mm/minute. Upon histology, the most commonly assessed structural and cellular factors were neovascularisation and macrophages respectively (n = 9 each). Structural analysis was mostly qualitative, where cellular analysis was equally likely to be quantitative. Eleven studies assessed adhesion formation, of which 8 used one of four scoring systems. Eight studies measured mesh shrinkage. Discussion In vivo studies assessing mesh for HH and DH repair are uncommon. Within this relatively young field, we encourage surgical and materials testing institutions to discuss its standardisation.

Revision Stapedotomies: the Role of Periprosthetic Scar Tissue Formation in the Development of Unsatisfactory Hearing Results after Stapedotomy

Introduction Revision stapes surgeries are difficult to perform, and their audiological results are inferior to primary surgeries. Objective Our goal was to identify the most common and most influential postoperative reasons that cause persistent air-bone gap (ABG) after the primary surgery. Our focus was concentrated on the mechanical dysfunctions in the middle ear, with special regard to postoperative adhesion formation. Methods We performed a retrospective case series study with 23 cases that underwent revision stapedotomies. Results A significant improvement was seen in ABG and air conduction levels after surgery. The periprosthetic adhesion formation was seen in 65% of the cases, and it was the primary cause behind the unsatisfactory hearing result in 30% of cases. There was no significant difference in the level of persistent ABGs after the primary surgery, in case of the intratympanic adhesion presence, compared with the presence of other surgical failures. Concerning hearing and ABG gain after revision surgery, the non-inferiority of the negative effect associated with adhesion was shown compared with the other reasons. Conclusion The revision stapedotomy is an efficient treatment option in case of persistent ABG. Periprosthetic adhesions are the most common intratympanic reasons for compromised audiological outcomes after stapedotomy.Adhesion formations have the same negative effect on ABG development as any other surgical failure, and the revision could be more challenging in these cases. These findings highlight the use of the most atraumatic surgical technique and preservation of intact intratympanic mucosa during middle ear surgery.

Effect of the p38 MAPK Inhibitor on the Expression of Metalloproteinases and Their Inhibitors during the Formation of Abdominal Adhesions

Background: The aim of this study was to assess the effect of blockade of the p38 mitogen-activated protein kinase (MAPK) on the expression of genes encoding metalloproteinases (MMPs) during the formation of adhesions in the abdominal cavity. Methods and Results: The experiments were carried out on male Wistar rats (n=75). The studies were carried out in two groups: Group 1 (control, n=35) – modelling the adhesive process; Group 2 (experimental, n=35) – modelling the adhesive process with intraperitoneal administration of Seroguard®—a prolonged form of the p38 MAPK inhibitor. The expression of the MMP1a, MMP2, MMP7, MMP9, and TIMP genes was assessed using real-time PCR. In the control group, overexpression of the MMP1a and MMP7 genes began from 6 hours after modeling the adhesive process, MMP9 – from Day 1, MMP2 – from Day 7 and persisted until the end of observation. With local blockade of p38 MAPK, the level of overexpression of genes encoding MMPs in the early stages was higher than in the control group (MMP1a – by Day 1; MMP7 – by 6 hours and Day 1, MMP9 – by 12 hours). From Day 3 to Day 14, the MMP1a and MMP7 expression in the experimental group was significantly lower than in the control group. Conclusion: The performed study demonstrated the involvement of different types of MMPs—collagenases (MMP1a), gelatinases (MMP2 and 9), matrilysins (MMP7)—in the rearrangement of the extracellular matrix during the process of adhesion formation in the abdominal cavity.

PuraStat RADA16 Self-Assembling Peptide Reduces Postoperative Abdominal Adhesion Formation in a Rabbit Cecal Sidewall Injury Model

Objective: To evaluate the effect of PuraStat (2.5% RADA16) administration on postoperative abdominal adhesion formation in an in vivo model.Methods: Anesthetized New Zealand white rabbits underwent cecal sidewall abrasion surgery in which the cecal serosa and juxtaposed parietal peritoneum were abraded after access through an abdominal midline incision. Eight animals were randomized to receive PuraStat administration at the interface of the injured tissues before incision closure, and five animals served as untreated controls. Treated animals received 3–12 ml PuraStat solution per lesion. Animals were sacrificed 14 days after surgery and examined for adhesion formation at the wound site.Results: At study terminus, adhesions were identified in 90% (9/10) of abraded cecum/peritoneal wound sites in untreated controls versus 25% (4/16) of PuraStat-treated sites (p = 0.004). Mean ± SD Total Adhesion Score (average of the values for extent + strength of the adhesion in both defects per animal; maximum score = 14 points) was significantly 76% lower in PuraStat-treated animals (2.0 ± 3.0 points) compared to untreated controls (8.2 ± 1.9 points) (p = 0.029). Mean adhesion coverage area of wound sites was 79% lower in PuraStat-treated animals than controls (p &lt; 0.001), and mean adhesion durability was 72% lower in PuraStat-treated animals versus controls (p = 0.005). Remnant hydrogel was observed at the wound sites of 75% of treated animals at postoperative Day 14.Conclusion: PuraStat treatment has a positive protective effect in the cecal sidewall injury model, and significantly reduces abdominal adhesion formation at the interface of the injured cecum and overlying peritoneal sidewall defect.

Neutrophil extracellular traps orchestrate formation of peritoneal adhesions

Peritoneal adhesions are a poorly understood but highly prevalent condition that can lead to intestinal obstruction, pelvic pain, and infertility. While there is consensus that stress-induced inflammation triggers peritoneal adhesions, the process of their formation remained elusive to date. Herein, we show that neutrophil extracellular traps (NETs) serve as essential scaffold for adhesion formation and that DNases interfere with this process. Thus, peritoneal adhesions in murine models and in humans showed that these lesions are largely based on extracellular DNA derived from neutrophils. Furthermore, treatment with DNASE1 or a DNASE1L3 analog significantly reduced or even prevented peritoneal adhesions in experimental models. These data not only suggest that NET formation plays an essential role in peritoneal adhesions but also show that therapeutic application of DNases can prevent the formation of peritoneal adhesions.

Gelatin/Polycaprolactone Electrospun Nanofibrous Membranes: The Effect of Composition and Physicochemical Properties on Postoperative Cardiac Adhesion

Cardiovascular diseases have become a major threat to human health. The adhesion formation is an inevitable pathophysiological event after cardiac surgery. We have previously shown that gelatin/polycaprolactone (GT/PCL, mass ratio 50:50) electrospun nanofibrous membranes have high potential in preventing postoperative cardiac adhesion, but the effect of GT:PCL composition on anti-adhesion efficacy was not investigated. Herein, nanofibrous membranes with different GT:PCL mass ratios of 0:100, 30:70, 50:50, and 70:30 were prepared via electrospinning. The 70:30 membrane failed to prevent postoperative cardiac adhesion, overly high GT contents significantly deteriorated the mechanical properties, which complicated the suturing during surgery and hardly maintained the structural integrity after implantation. Unexpectedly, the 0:100 membrane (no gelatin contained) could not effectively prevent either, since its large pore size allowed the penetration of numerous inflammatory cells to elicit a severe inflammatory response. Only the GT:PCL 50:50 membrane exhibited excellent mechanical properties, good biocompatibility and effective anti-cell penetration ability, which could serve as a physical barrier to prevent postoperative cardiac adhesion and might be suitable for other biomedical applications such as wound healing, guided tissue or bone regeneration.

Prevention of Intra-Abdominal Adhesions Using the Combination of Mediclore® and a Statin

<b><i>Purpose:</i></b> This study investigated the antiadhesive effects of Mediclore®, rosuvastatin, and a combination of Mediclore and rosuvastatin in a rat adhesion model. <b><i>Methods:</i></b> The adhesion models (a total of 58 adult male rats) were divided into 4 groups. The control group (group C) received no special materials except for a saline. The experimental groups were treated with 5 mL of Mediclore (group M), rosuvastatin (group R), or rosuvastatin and Mediclore (group RM), and these materials were intraperitoneally placed under the incision. At postoperative day 14, the rats underwent re-laparotomy and adhesiolysis. Three investigators blinded to group assignment scored the extent of adhesion formation, the numbers of remote adhesions, and the extent of acute/chronic inflammation, fibrosis, edema, and congestion on resected specimens via histologic examination. <b><i>Results:</i></b> The macroscopic adhesion score in group RM (7.27 ± 3.51) was significantly lower than those in groups C (13.36 ± 2.24) and R (11.71 ± 1.98); group M (9.13 ± 4.09) had a significantly lower adhesion score than group C. The number of remote adhesions was significantly lower in groups R and RM than in group C. The acute inflammation score, chronic inflammation score, and fibrosis score in group RM; the acute inflammation score in group R; and the fibrosis score in group M were significantly lower than those in group C. <b><i>Conclusion:</i></b> The intraperitoneal application of Mediclore and a combination of Mediclore and rosuvastatin effectively reduced postoperative adhesions.