Healing in other tissues

The Effectiveness of Adipose Tissue-Derived Mesenchymal Stem Cells Mixed with Platelet-Rich Plasma in the Healing of Inflammatory Bowel Anastomoses: A Pre-Clinical Study in Rats

Introduction: Multiple factors have been linked with increased risk of anastomotic leak in bowel surgery, including infections, inflammatory bowel disease, patient comorbidities and poor surgical technique. The aim of this study was to investigate the positive effect, if any, of adipose derived mesenchymal stem cells (MSCs) mixed with platelet-rich plasma (PRP) in the healing of bowel anastomoses, in an inflammatory environment after establishment of experimental colitis. Materials and Methods: Thirty-five male Wistar rats were divided into five groups of seven animals: normal controls, colitis controls, PRP, MSCs, and PRP+MSCs. All groups underwent laparotomy, one-cm segmental colectomy and anastomosis in situ. In the colitis group, colectomy was performed at the affected area. Colitis was previously established by transrectal administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS) except for the normal controls. Post-mortem histopathological, tissue hydroxyproline and anastomotic bursting pressure (ABP) assessments were performed. The Mann-Whitney U test was used to assess statistical significance differences between groups. Results: No perioperative mortality was noted. Tissue hydroxyproline and ABP were significantly increased in the group of PRP+MSCs compared to colitis controls (p = 0.0151 and p = 0.0104, respectively). Inflammatory cell infiltration was lower and fibroblast activity higher in PRP+MSCs group, but not statistically significant (p > 0.05). Neoangiogenesis (p = 0.0073) and anastomotic area epithelialization (p = 0.0182) were significantly higher in PRP + MSCs group compared to colitis controls. Discussion: The synergistic effect of the PRP and MSCs is apparently responsible for the improved healing markers in bowel anastomoses even on inflammatory bowel. This gives hope for primary anastomoses and stoma saving in many emergency and/or elective circumstances, especially in immunocompromised or malnourished patients, even in cases with inflammation or peritonitis. Clinical studies should follow in order to support the clinical application of PRP+MSCs in gastrointestinal anastomoses.

The Effect of Genistein on Anastomotic Healing in Intestinal Ischemia/Reperfusion Injury

INTRODUCTION

Genistein is a natural isoflavonoid and has several pharmacological effects, such as antioxidant, antitumor activity, and improvement of glucose metabolism. The safety of intestinal anastomosis after ischemia-reperfusion (I/R) injury is a critical issue for surgeons. This experimental study aimed to investigate the effects of genistein on anastomotic healing after intestinal I/R injury.

METHODS

A total of 36 male Wistar Albino rats were divided into four groups: control, I/R, genistein, and genistein + I/R. The control group received segmental ileal resection and ileoileal anastomosis. The I/R group received resection + anastomosis after intestinal I/R. The genistein group was administered subcutaneous injection of 1 mg/kg genistein 12 h and 1 h before the procedure and received ileal resection + anastomosis. The genistein + I/R group received I/R + ileal resection + anastomosis after genistein injection. Anastomotic bursting pressure, hydroxyproline, superoxide dismutase, and glutathione peroxidase levels and histopathological wound healing scores of all rats were measured on postoperative day 5.

RESULTS

The anastomotic bursting pressure was significantly higher in the genistein and genistein + I/R groups (P < 0.001). Genistein increased the hydroxyproline concentration and the superoxide dismutase and glutathione peroxidase levels in the intestinal anastomosis (P < 0.001). In histopathological assessment, the mean wound healing score was significantly higher in the genistein group than in the other groups (P < 0.001).

CONCLUSIONS

Genistein, with its anti-inflammatory and antioxidant properties, shows protective effects against increased oxidative stress after intestinal I/R injury and contributes positively to intestinal anastomotic healing.

Impact of Deserosalization on Small Bowel Anastomosis Healing in Swine: A Pilot Study

BACKGROUND

Healing is related to gastrointestinal anastomotic leak, which is a severe and common complication. This study aimed to investigate the feasibility and the impact of deserosalization on healing of jejuno-jejunal anastomoses in an animal model.

MATERIALS AND METHODS

Seven swine underwent three types of side-to-side jejuno-jejunal anastomosis twice and survived seven days. Three different types of jejuno-jejunal side-to-side anastomoses were performed twice at 20-cm distance from each other in each animal: no serosa removal, one-sided, and two-sided serosa removal, respectively. Bursting pressure, tissue hydroxyproline concentration, and pathology scores were evaluated.

RESULTS

Hydroxyproline tissue concentration was a mean±standard deviation of 0.37±0.09, 0.38±0.08, and 0.30±0.05 nmoI/ml respectively (p<0.05). Bursting pressure was a mean±standard deviation of 59.02±8.60, 73.20±11.09, and 100.01±7.49 mmHg, respectively (p<0.001). The histopathological assessment did not find any statistically significant differences.

CONCLUSION

Deserosalization in jejuno-jejunal anastomosis was technically feasible and seemed to improve mechanical strength and collagen deposition in this experimental porcine model. Further investigation is warranted.

Platelet-Rich Fibrin Scaffolds for Cartilage and Tendon Regenerative Medicine: From Bench to Bedside

Nowadays, research in Tissue Engineering and Regenerative Medicine is focusing on the identification of instructive scaffolds to address the requirements of both clinicians and patients to achieve prompt and adequate healing in case of injury. Among biomaterials, hemocomponents, and in particular Platelet-rich Fibrin matrices, have aroused widespread interest, acting as delivery platforms for growth factors, cytokines and immune/stem-like cells for immunomodulation; their autologous origin and ready availability are also noteworthy aspects, as safety- and cost-related factors and practical aspects make it possible to shorten surgical interventions. In fact, several authors have focused on the use of Platelet-rich Fibrin in cartilage and tendon tissue engineering, reporting an increasing number of in vitro, pre-clinical and clinical studies. This narrative review attempts to compare the relevant advances in the field, with particular reference being made to the regenerative role of platelet-derived growth factors, as well as the main pre-clinical and clinical research on Platelet-rich Fibrin in chondrogenesis and tenogenesis, thereby providing a basis for critical revision of the topic.

Perioperative use of nonsteroidal anti-inflammatory drugs and the risk of anastomotic failure in emergency general surgery

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used analgesic and anti-inflammatory adjuncts. Nonsteroidal anti-inflammatory drug administration may potentially increase the risk of postoperative gastrointestinal anastomotic failure (AF). We aim to determine if perioperative NSAID utilization influences gastrointestinal AF in emergency general surgery (EGS) patients undergoing gastrointestinal resection and anastomosis.

METHODS

Post hoc analysis of a multi-institutional prospectively collected database was performed. Anastomotic failure was defined as the occurrence of a dehiscence/leak, fistula, or abscess. Patients using NSAIDs were compared with those without. Summary, univariate, and multivariable analyses were performed.

RESULTS

Five hundred thirty-three patients met inclusion criteria with a mean (±SD) age of 60 ± 17.5 years, 53% men. Forty-six percent (n = 244) of the patients were using perioperative NSAIDs. Gastrointestinal AF rate between NSAID and no NSAID was 13.9% versus 10.7% (p = 0.26). No differences existed between groups with respect to perioperative steroid use (16.8% vs. 13.8%; p = 0.34) or mortality (7.39% vs. 6.92%, p = 0.84). Multivariable analysis demonstrated that perioperative corticosteroid (odds ratio, 2.28; 95% confidence interval, 1.04-4.81) use and the presence of a colocolonic or colorectal anastomoses were independently associated with AF. A subset analysis of the NSAIDs cohort demonstrated an increased AF rate in colocolonic or colorectal anastomosis compared with enteroenteric or enterocolonic anastomoses (30.0% vs. 13.0%; p = 0.03).

CONCLUSION

Perioperative NSAID utilization appears to be safe in EGS patients undergoing small-bowel resection and anastomosis. Nonsteroidal anti-inflammatory drug administration should be used cautiously in EGS patients with colon or rectal anastomoses. Future randomized trials should validate the effects of perioperative NSAIDs use on AF.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Endoscopy in the early postoperative setting after primary gastrointestinal anastomosis

INTRODUCTION

Gastrointestinal anastomoses may require early evaluation and treatment via flexible endoscopic techniques when complications arise. There is reticence, however, to perform endoscopy given the applied mechanical forces. We aimed to identify the incidence of gastrointestinal anastomotic perforation or disruption resulting from endoscopy performed ≤6 weeks of anastomoses.

METHODS

Review of patients from 2002 to 2013 who underwent flexible endoscopy within 6 weeks of creation of gastrointestinal anastomosis. Exclusion criteria included intraoperative endoscopy, anastomotic perforation prior to endoscopy, and endoscopy remote from the anastomotic site. Data are presented as median (interquartile range; IQR) or percentages as appropriate.

RESULTS

Twenty-four patients met our criteria (age 69 years [IQR 54-77], 54% men]). Endoscopy was performed at a median postoperative time of 18 days (IQR 8-30). Indications for endoscopy included bleeding (66%), obstruction (13%), pain (13%), concern for pancreatic duct leak (4%), and concern for ischemia (4%). Six patients underwent therapeutic endoscopic procedures including coagulation (8%), balloon dilation (8%), tube decompression (8%), and stent placement (4%). There were no anastomotic perforations or disruptions as a result of endoscopy.

CONCLUSION

Despite theoretical risks of adverse events of flexible endoscopy in the early postoperative period, no endoscopic perforations or disruptions occurred in recently created surgical anastomoses.

The role of plastic surgery for soft tissue coverage of the diabetic foot and ankle

The goal of wound healing is to obtain the best closure through the least morbid means. In the surgical treatment of the diabetic foot and ankle, the reconstructive foot and ankle surgeon is tasked with the challenge of repairing a variety of tissue defects. The decision for wound closure depends on the location of the wound and host factors. In order of increasing complexity, the clinician should consider the reconstruction decision ladder algorithm. Wound evaluation coupled with the knowledge of various closure techniques and their indications will arm the surgeon with the tools for a successful closure.

Is combined therapy more effective than growth hormone or hyperbaric oxygen alone in the healing of left ischemic and non-ischemic colonic anastomoses?

OBJECTIVE

Our aim was to investigate the effects of growth hormone (GH), hyperbaric oxygen and combined therapy on normal and ischemic colonic anastomoses in rats.

METHODS

Eighty male Wistar rats were divided into eight groups (n = 10). In the first four groups, non-ischemic colonic anastomosis was performed, whereas in the remaining four groups, ischemic colonic anastomosis was performed. In groups 5, 6, 7, and 8, colonic ischemia was established by ligating 2 cm of the mesocolon on either side of the anastomosis. The control groups (1 and 5) received no treatment. Hyperbaric oxygen therapy was initiated immediately after surgery and continued for 4 days in groups 3 and 4. Groups 2 and 6 received recombinant human growth hormone, whereas groups 4 and 8 received GH and hyperbaric oxygen treatment. Relaparotomy was performed on postoperative day 4, and a perianastomotic colon segment 2 cm in length was excised for the detection of biochemical and mechanical parameters of anastomotic healing and histopathological evaluation.

RESULTS

Combined treatment with hyperbaric oxygen and GH increased the mean bursting pressure values in all of the groups, and a statistically significant increase was noted in the ischemic groups compared to the controls (p<0.05). This improvement was more evident in the ischemic and normal groups treated with combined therapy. In addition, a histopathological evaluation of anastomotic neovascularization and collagen deposition showed significant differences among the groups.

CONCLUSIONS

Combined treatment with recombinant human growth hormone and hyperbaric oxygen resulted in a favorable therapeutic effect on the healing of ischemic colonic anastomoses.

VEGF-A and FGF gene therapy accelerate healing of ischemic colonic anastomoses (experimental study)

BACKGROUND

Reducing ischemic damage is one of the goals of surgery. The aim of this study was to apply human VEGF-A and FGF-2 DNA-mediated gene therapy in order to identify their effects in the healing of ischemic colon anastomoses and eliminating the negative effects of ischemia.

METHODS

Forty male Wistar albino rats weighing 250-280 g were divided into five equal groups (n = 8) as follows: group 1: control, ischemic left colonic anastomosis; group; 2: ischemic left colonic anastomosis with control plasmid delivery; group 3: ischemic left colonic anastomosis with VEGF plasmid delivery; group 4: ischemic left colonic anastomosis with FGF plasmid delivery; group 5: ischemic left colonic anastomosis with VEGF and FGF plasmid delivery. All rats were sacrificed on the 4th postoperative day. Anastomosis burst pressures were measured for mechanical examination of anastomosis. Tissue hydroxyprolin, VEGF and FGF levels were determined as biochemical parameters. Necrosis, epithelisation, inflammatory processes, fibroblastic activity, collagen deposition and neovascularisation at the anastomic site were studied.

RESULTS

VEGF, FGF and combined therapy significantly accelerated many of the histological parameters of healing, including fibroblast activation, collagen deposition, and angiogenesis, and augmented the levels of hydroxyproline and bursting pressure.

CONCLUSIONS

This is the first study to use gene therapy with growth factors for the healing of ischemic colonic anastomosis. This therapy can be effectively used in increasing ischemic anastomosis wound healing.

Mesenchymal stem cells improve the healing of ischemic colonic anastomoses (experimental study)

OBJECTIVE

The goal of this study is to examine if allogenic mesenchymal stem cell (MSC) transplantation is a useful therapy for left ischemic colon anastomosis in rats. Problems with anastomosis healing may lead to serious postoperative complications. Bone marrow-derived mesenchymal stem cells (BM-MSCs), which are also referred to as stromal progenitor cells, are self-renewing and expandable stem cells. Recent studies have suggested that BM-MSCs play a crucial role in the processes of intestinal repair and accelerate angiogenesis.

METHODS

MSCs were isolated from rats before analysis by light and scanning electron microscopy. Forty male Wistar albino rats weighing 250-280 g were divided into four equal groups (n = 10) as follows: group 1: control, ischemic left colonic anastomoses (fourth day); group 2: control, ischemic left colonic anastomoses (seventh day); group 3: ischemic left colonic anastomoses + locally transplanted BM-MSCs (fourth day); group 4: ischemic left colonic anastomoses + locally transplanted BM-MSCs (seventh day). Histopathological features and anastomotic strength were evaluated.

RESULTS

BM-MSCs therapy significantly accelerated all of the healing parameters for ischemic colonic anastomosis except for inflammation on the fourth day. On the seventh day, BM-MSCs augmented the levels of the hydroxyproline and bursting pressure. Histological parameters, especially angiogenesis, were also found to be important for healing of ischemic colonic anastomoses.

CONCLUSIONS

This is the first study to use locally transplanted cell therapy for the healing of ischemic colonic anastomosis. BM-MSCs therapy significantly accelerated all of the healing parameters for ischemic colonic anastomosis.

Covering the colon anastomoses with amniotic membrane prevents the negative effects of early intraperitoneal 5-FU administration on anastomotic healing

PURPOSE

This study investigated whether covering the colonic anastomoses with amniotic membrane (AM) protects the anastomotic healing from the adverse effects of immediate 5-fluorouracil (5-FU) administration.

METHODS

One hundred twenty wistar albino rats were randomized to one of four groups (I-IV, 30 rats in each) and underwent a standardized left colon resection and anastomoses. The anastomoses of the rats in groups II (AM) and IV (5-FU + AM) were covered with AM. Saline solution (2 ml/day; groups I (control) and II) or 5-FU (20 mg/kg/day; groups III (5-FU) and IV) was administered to the rats intraperitoneally once daily from the day of operation until sacrificed. Half of each group was sacrificed on the postoperative day 4 (IA, IIA, IIIA, and IVA) and other half on the postoperative day 8 (IB, IIB, IIIB, and IVB), and their anastomoses were evaluated when sacrificed.

RESULTS

The dehiscence rate of anastomotic dehiscence and adhesion formation were significantly higher in groups IIIA and IIIB compared with groups IVA and IVB, respectively. Bursting pressure was significantly higher in the 5-FU + AM groups than in the 5-FU groups. The inflammatory cell infiltration was significantly lower in groups IIIA and IVA compared with group IA, in groups IIIB and IVB compared with group IB, and in group IVA compared with group IIIA. Neoangiogenesis, fibroblast activity, collagen deposition, and hydroxyproline levels were significantly higher in the 5FU + AM groups compared with control and 5-FU groups. Malondialdehyde levels were significantly higher in the 5-FU groups than in the 5-FU + AM groups.

CONCLUSION

Covering colon anastomoses with AM protects them, preventing leakage and reversing the negative effects of 5-FU administration.

Effects of the histamine H2 receptor antagonist famotidine on the healing of colonic anastomosis in rats

BACKGROUND

Failure of anastomotic healing is one of the major complications in colorectal surgery. Because histamine plays an important role in immune and inflammatory reactions, we demonstrate the effects of famotidine on the healing of colonic anastomosis in rats.

METHODS

Twenty-eight Sprague-Dawley rats were used in the study. Excision and end-to-end anastomosis was performed in the distal colon of the rat. The Famotidine Group received 2 mg/kg/day famotidine; the Control Group received the same amount of saline. Bursting pressure of anastomoses and hydroxyproline content of perianastomotic tissues were evaluated on the third and seventh days following surgery.

RESULTS

Bursting pressures and hydroxyproline contents for the Famotidine Group were significantly lower than the equivalent parameters for the Control Group on both the third and seventh days post-surgery.

CONCLUSIONS

According to our findings, famotidine exerts detrimental effects on the anastomotic bursting pressure and hydroxyproline content of perianastomotic tissues in the colon of rats.

Repair of experimental Achilles tenotomy with porcine renal capsule material in a rat model

Porcine small intestinal submucosa (SIS) is a collagenous acellular matrix which has found substantial utility as a tissue growth scaffold. In the present study, the utility of porcine renal capsule matrix (RCM) was compared to SIS in a rat Achilles tenotomy repair model. Groups of rats underwent surgical tenotomy followed by either no repair, repair with a SIS graft, or repair with a RCM graft. The weight-bearing ability of the manipulated limb was evaluated for 10 days following surgery using a subjective scale. Tenotomy sites sampled 28 days after surgery were numerically graded for degree of histologic change. There were no statistically significant differences between groups with respect to return to weight-bearing ability (p >or= 0.05) or degree of histologic change (p >or= 0.001); however, a non-significant trend suggested that rats treated with SIS or RCM experienced a faster return to limb function than untreated rats, and RCM-treated rats had slightly higher scores for degree of histologic change, suggesting a more rapid repair of the tenotomy site than in SIS-treated or untreated rats. The harvested tenotomy sites in all treatment groups were characterized by marked fibroplasia and presence of macrophages. Remnants of SIS surrounded by macrophages and multi-nucleated giant cells were still present in some rats, however remnants of RCM were not observed, suggesting more rapid incorporation of RCM. The results show that RCM is equivalent to SIS as a material for repair of Achilles tendon injury and merits further study in other tendon injury models.

The effect of erythropoietin on healing of obstructive vs nonobstructive left colonic anastomosis: an experimental study

Background

Anastomotic leakage is an important problem following primary resection in the left colon and is even more prominent when obstruction is present. We aimed to evaluate the possible effects of erythropoietin on the healing of anastomosis under both obstructive and non-obstructive states.

Methods

Forty male Wistar albino rats were divided into four groups. In group I, two cm left colonic resection and primary anastomosis were done. In group II, left colon were completely ligated and 24 hours later animals were re-operated for segmental resection. The same procedures were performed for rats in group III and IV in respect to group I and II and, 500 IU/kg a day erythropoietin were given in the latter two groups for seven days. For the quantative description of anastomotic healing mechanical, biochemical and histopathological parameters were employed on the seventh day and the animals were sacrificied.

Results

Although erythropoietin had positive effects on bursting pressure in group IV when compared to group II, it has no effect in group III. Despite the increased tissue hydroxyproline levels in group IV, erythropoietin failed to show any effects in group III.

Erythropoietin had positive effects on neovascularization, fibroblast proliferiation and storage of collagen in group IV.

Conclusion

We failed to find any direct and evident effects of erythropoietin on healing of left colonic anastomosis. On the other hand, erythropoietin might prevent negative effects of obstruction on healing.

The effect of purified micronized flavonoid fraction on the healing of anastomoses in the colon in rats

PURPOSE

Anastomotic leakage of colonic and rectal anastomoses is a major complication after large intestine surgery. Many factors influence the healing of colon anastomoses. Flavonoids have been recognized for centuries as physiologically active constituents that are used to treat human diseases. We studied the effects of a clinically used, micronized, purified flavonoid fraction on the healing of colonic anastomosis in rats.

METHODS

Male Sprague-Dawley rats were used. The flavonoid group of rats received 100 mg/kg per day of Daflon for 14 days until surgery. Thereafter, a resection and anastomosis were performed. The bursting pressure of the anastomoses and the hydroxyproline levels of the perianastomotic tissue were determined to evaluate the healing on the third and seventh days of surgery for both flavonoid and control groups.

RESULTS

The bursting pressure of the flavonoid group was higher on the seventh day. The hydroxyproline levels of the flavonoid group were significantly higher than in the control group on both the third and seventh days after surgery.

CONCLUSIONS

Although the micronized purified flavonoid fraction has some inhibitory properties on the healing of the anastomosis, its net effect was to obtain a better anastomotic healing of the colon in rats.

Expression of growth factors in the early phase of supraspinatus tendon healing in rabbits

Growth factors are known to appear during wound healing. We hypothesized that growth factors would also appear during the healing process of a rotator cuff tear. We determined the expression of various growth factors during healing of acute rotator cuff tears in the rabbit. We made a full-thickness defect in the supraspinatus tendon of 27 Japanese white rabbits. The shoulders were harvested on days 1, 3, 5, 7, 9, 11, 14, 21, and 28 postoperatively (n = 3 at each time point). We assessed the expression of basic fibroblast growth factor, insulin-like growth factor 1, platelet-derived growth factor, and transforming growth factor beta. Basic fibroblast growth factor appeared with its peak on days 7 and 9, insulin-like growth factor 1 appeared with its peak on day 5, platelet-derived growth factor appeared with a mild expression between days 7 and 14, and transforming growth factor beta appeared with constant mild expression throughout the observation period. It is likely that each of these growth factors plays a role in the early phase of healing of the supraspinatus tendon in rabbits.

Microarray analysis of healing rat Achilles tendon: evidence for glutamate signaling mechanisms and embryonic gene expression in healing tendon tissue

Tendon healing is a complex process consisting of a large number of intricate pathways roughly divided into the phases of inflammation, proliferation, and remodeling. Although these processes have been extensively studied at a variety of levels in recent years, there is still much that remains unknown. This study used microarray analyses to investigate the process at a genetic level in healing rat Achilles tendon at 1, 7, and 21 days postinjury, roughly representing the inflammation, proliferation, and remodeling phases. An interesting temporal expression profile was demonstrated, identifying both known and novel genes and pathways involved in the progression of tendon healing. Both inflammatory response and pro-proliferative genes were shown to be significantly upregulated from 24 h postinjury through to 21 days. Day 7 showed the largest increase in genetic activity, particularly with the expression of collagens and other extracellular matrix genes. Interestingly, there was also evidence of central nervous system-like glutamate-based signaling machinery present in tendon cells, as has recently been shown in bone. This type of signaling mechanism has not previously been shown to exist in tendon. Another novel finding from these analyses is that there appears to be several genes upregulated during healing which have exclusively or primarily been characterized as key modulators of proliferation and patterning during embryonic development. This may suggest that similar pathways are employed in wound healing as in the tightly regulated progression of growth and development in the embryo. These results could be of use in designing novel gene-based therapies to increase the efficacy and efficiency of tendon healing.

Clinical review: Healing in gastrointestinal anastomoses, Part I

Gastrointestinal healing is a topic rarely reviewed in the literature, yet it is of paramount importance to the surgeon. Failure of anastomotic healing may lead to life-threatening complications, additional surgical procedures, increased length of stay, increased cost, long-term disability, and reduced quality of life for the patient. The goal of this article is to review the biological response to wounded tissue, to outline discrete differences between skin and gastrointestinal healing, to discuss local and systemic factors important to gastrointestinal healing, and to compare methods of measuring collagen content and strength of the newly formed anastomosis. Part II of this review will focus on techniques and therapies available to optimize anastomotic healing.

Factor XIII Therapy of Anastomotic Leak, and Circulating Growth Factors

Wound healing is far more rapid in the gastrointestinal tract than in the skin. Once dehiscence of a surgical anastomosis in the gastrointestinal tract occurs, the high collagenase activity in the gastrointestinal tract may delay wound healing and promote the formation of a nonhealing fistula. Because factor XIII promotes cross-linking of fibrin during the early phase of wound healing, we investigated the effect of factor XIII concentrate on 16 anastomotic leaks and a nonhealing fistula. A 240-U dose of factor XIII concentrate (Fibrogammin P) was administrated intravenously for 5 days. Factor XIII activity and plasma levels of epidermal growth factor (EGF), transforming growth factor (TGF)-beta, and interleukin-6 were measured before treatment and 1 day and 7 days after the end of treatment. Clinical outcomes were evaluated on the basis of the findings of contrast radiography, computed tomography, and drainage volume. Improvement relevant to the therapy was observed in 15 cases (88.2%). Factor XIII activity increased to more than 70% of the normal value in 11 cases (64.7%) but remained at 40% to 70% of the normal value in 6 cases (35.3%). Plasma EGF and TGF-betalevels increased in patients with improvement but were unchanged in patients without improvement. Our findings suggest that factor XIII significantly accelerates wound healing of anastomotic leaks and nonhealing fistulas by increasing circulating growth factors after systemic administration.

Total flavones of Hippophae rhamnoides promotes early restoration of ultimate stress of healing patellar tendon in a rat model

Traditional Chinese herbal medicine has long been used for treatment of tendon injuries. Comparing to the modern way of treatments, Traditional Chinese medicine also stresses on strategies to promote the inherent healing capacity of tendons. Hippophae rhamnoides, known as Shaji, is one of Chinese herbal drugs that are traditionally used to promote tendon and ligament injuries. The total flavones of H. rhamnoides (TFH), with major constituents including quercetin, isorhamnetin and kaempferol, have been demonstrated with most of the bioactive properties of Shaji. In the present study, we evaluated the potential effect of TFH in the restoration of ultimate stress of healing patellar tendon in a well-established gap wound model in rats. A 0.1 mg TFH was injected to wound 1 day after the injury, and the ultimate stress of the healing tendon was measured at day 14 post-injury. The results showed that the ultimate stress of the healing tendon was significantly promoted by injection of TFH, increasing from 30 to 50% as compared to saline control. Excessive fibrotic response was not found in TFH-treated animals, but an enhanced collagen deposition and a better fibre alignment were observed. The results suggest that TFH may improve the ultimate stress of healing tendons at early stages, which implies possible earlier rehabilitation programme and better recovery.

Functional efficacy of tendon repair processes

Despite various attempts to repair and replace injured tendon, an understanding of the repair processes and a systematic approach to achieving functional efficacy remain elusive. In this review the epidemiology of tendon injury and repair is first examined. Using a traditional paradigm for repair assessment, the biology and biomechanics of normal tendon, natural healing, and repair are then explored. New treatment strategies such as functional tissue engineering are discussed, including a functional approach to treatment that involves the development of in vivo functional design parameters to judge the acceptability of a repair outcome. The paper concludes with future directions.

The roles of growth factors in tendon and ligament healing

Tendon healing is a complex and highly-regulated process that is initiated, sustained and eventually terminated by a large number and variety of molecules. Growth factors represent one of the most important of the molecular families involved in healing, and a considerable number of studies have been undertaken in an effort to elucidate their many functions. This review covers some of the recent investigations into the roles of five growth factors whose activities have been best characterised during tendon healing: insulin-like growth factor-I (IGF-I), transforming growth factor beta (TGFbeta), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and basic fibroblast growth factor (bFGF). All five are markedly up-regulated following tendon injury and are active at multiple stages of the healing process. IGF-I has been shown to be highly expressed during the early inflammatory phase in a number of animal tendon healing models, and appears to aid in the proliferation and migration of fibroblasts and to subsequently increase collagen production. TGFbeta is also active during inflammation, and has a variety of effects including the regulation of cellular migration and proliferation, and fibronectin binding interactions. VEGF is produced at its highest levels only after the inflammatory phase, at which time it is a powerful stimulator of angiogenesis. PDGF is produced shortly after tendon damage and helps to stimulate the production of other growth factors, including IGF-I, and has roles in tissue remodelling. In vitro and in vivo studies have shown that bFGF is both a powerful stimulator of angiogenesis and a regulator of cellular migration and proliferation. This review also covers some of the most recent studies into the use of these molecules as therapeutic agents to increase the efficacy and efficiency of tendon and ligament healing. Studies into the effects of the exogenous application of TGFbeta, IGF-I, PDGF and bFGF into the wound site singly and in combination have shown promise, significantly decreasing a number of parameters used to define the functional deficit of a healing tendon. Application of IGF-I has been shown to increase in the Achilles Functional Index and the breaking energy of injured rat tendon. TGFbeta and PDGF have been shown separately to increase the breaking energy of healing tendon. Finally, application of bFGF has been shown to promote cellular proliferation and collagen synthesis in vivo.

Acute wound healing: the biology of acute wound failure

Acute wound healing failure is an important source of morbidity and mortality for surgical patients. Many incisional hernias, gastrointestinal anastomotic leaks, and vascular pseudoaneurysms occur despite patient optimization and standardized surgical technique. Modern surgical experience suggests that biologic and mechanical pathways overlap during "normal" acute wound healing. The cellular and molecular processes activated to repair tissue from the moment of injury are under the control of biologic and mechanical signals. Successful acute wound healing occurs when a dynamic balance is met between the loads placed across a provisional matrix and the feedback and feed-forward responses of repair cells.

Understanding endoluminal gastroplications: a histopathologic analysis of intraluminal suture plications

BACKGROUND

Endoluminal gastroplication is used to treat GERD, with modest results. Little is known of the histologic reaction to endosutures. Thus, the histologic response to intraluminal plications at different penetration depths within the gastric wall was studied in an animal model.

METHODS

Intraluminal gastroplications were performed through a laparotomy in 18 New Zealand rabbits. Three sets of everted plications were placed at different penetration depths in each stomach: submucosa (SMpl), muscularis propria (Mpl), and serosa (Spl). Animals were randomized to survival times of 3, 10, or 60 days (respectively, Groups I, II, and III). Plications were compared with a grade scale for each histologic healing phase and gross inspection.

RESULTS

Fusion between folds was absent in all groups. Serosa differed from muscularis propria with respect to the proportion of samples with microscopic ischemia (67% vs. 8%; p = 0.015), remaining sutures in Group III (33% vs. 3%; p < 0.05 in a single test of significance, but correction for multiple testing removes this significance), and remaining plications in Group II (96% vs. 54%; p < 0.05 in a single test of significance, but correction for multiple testing removes this significance). All of the total and partial histologic scores for the corresponding healing phase in each group escalated with penetration depth. Overall comparison of the histologic scores showed a significant difference among the plications in the proliferation (Group II, p = 0.004) and maturation (Group II, p = 0.009) phases. Total scores also differed among the plications in Groups II (p < 0.001) and III (p < 0.001). Plications were absent in all of Group III, with Spl resulting only in a flat scar.

CONCLUSION

Everted intraluminal gastroplications do not result in fusion between folds irrespective of suture-penetration depth. A flat scar is the final outcome and appears proportional to the amount of ischemia, foreign body reaction, and suture depth.

Paracrine activation of extracellular signal-regulated kinase in a simple in vitro model of wounded osteoblasts

The immediate signal-transduction response of osteoblasts to acute trauma is poorly characterized. We have developed a simple in vitro model for osteoblast trauma to investigate aspects of the molecular mechanisms of wound healing in bone. Herein we report the specific, rapid, and transient phosphorylation of extracellular signal-regulated kinase (ERK) 1 and 2 in osteoblasts as a response to disruption ("wounding") of a confluent monolayer. The mitogen-activated protein kinase (MAPK) cascades of p38 and stress-activated protein kinase/c-jun N-terminal kinase (SAPK/JNK) were not activated by this perturbation. The response to wounding was equivalent to the activation of ERK by the addition of exogenous growth factors, and the perturbation-dependent phosphorylation of ERK can be suppressed by an inhibitor of heparin-binding growth factors. Conditioned media from wounded monolayers can induce the phosphorylation of ERK in unperturbed monolayers. Using immunohistochemistry, it was demonstrated that the cells with increased levels of phosphorylated ERK were not localized to the wound edges. These results indicate that ERK activation is the result of an autocrine/paracrine response by osteoblasts to trauma. We speculate that osteoblasts respond to trauma with the release of soluble factors as part of an autocrine/paracrine modulation of the wound-healing process in bone.

Effect of persistently elevated intraabdominal pressure on healing of colonic anastomoses

BACKGROUND

The adverse effects of elevated intraabdominal pressure (IAP) on abdominal organs are realized, but its influence on anastomotic healing has not been studied. The aim of this study was to evaluate the effect of elevated IAP on healing of colonic anastomoses.

METHODS

Thirty rats, which all had right colonic anastomoses, were divided into five groups. Group 1 was the control group, and group 2 had fecal peritonitis. IAP was maintained between 4 to 6 mm Hg in group 3, 8 to 12 mm Hg in group 4, and 14 to 18 mm Hg in group 5 until all rats were sacrificed on day 4. Bursting pressures and tissue hydroxyproline concentrations of anastomoses were then analyzed and compared.

RESULTS

Mean +/- SEM of bursting pressures were 143+/-2.9 mm Hg in group 1, 72+/-14.4 mm Hg in group 2, 77.3+/-7.9 mm Hg in group 3, 57.5+/-11.2 mm Hg in group 4, and 40.1+/-9.6 mm Hg in group 5 (P<0.0001, one-way analysis of variance [ANOVA]). Mean +/- SEM of tissue hydroxyproline concentrations were 5.3+/-0.3 microg/mg in group 1, 4.7+/-0.5 microg/mg in group 2, 4.6+/-0.6 microg/mg in group 3, 3.6+/-0.5 microg/mg in group 4, and 2.4+/-0.2 microg/mg in group 5 (P = 0.0026, one-way ANOVA). The bursting pressure and hydroxyproline concentrations had good correlation (P<0.001, r = 0.76).

CONCLUSIONS

Elevated IAP delays healing of colonic anastomoses and 4 to 6 mm Hg IAP delays healing as much as fecal peritonitis. More elevated IAP delays healing more than fecal peritonitis. These events may be clinically important and may result from local-systemic effects of IAP.

Optimisation of the biology of soft tissue repair

As identified in this review, over the past twenty years there have been a number of very exciting new developments in the quest to optimise soft tissue repair. Comparing fetal soft tissue injuries, which heal by regeneration, to the adult processes of healing by inflammation-induced scar formation has led to a number of insights into how the latter may be improved. Seeding wounds with embryonic stem cells, bridging gaps with cell-derived "engineered tissues", addition of exogenous hyaluronic acid and modification of wounds to either enhance the growth factors which have been implicated in regeneration (e.g. TGF-B3) or block those implicated in scar formation (eg. TGF-B1) have all shown promise. Our group has quantified numerous cellular, molecular, biomechanical and matrix abnormalities of scar in a rabbit model of ligament healing. Based on these studies which we review here, three matrix deficiencies have been identified which appear to have specific implications to scar weakness: organisational "flaws", abnormal hydroxypyridinoline collagen cross-link densities and abnormally small, slow-maturing collagen fibrils. In tests aimed at finding therapeutic solutions in this model, the addition of a 7ug bolus of TGF-B1 at day 21 or 2.5ng/day of TGF-B1 being pumped into a wound x 21 days increased the size of ligament scars but did not improve their material strength. It also did not alter any of the above-noted matrix deficiencies. A liposome-mediated anti-sense gene therapy approach aimed at decreasing the expression of the proteoglycan decorin in 21-day scars, however, has significantly increased the size of scar collagen fibrils as well as improved these scars mechanically. Based on these positive results from a single dose of only one targeted molecule, we believe that this gene therapy approach has great potential for further scar improvement. If combined with some of the other biological strategies reviewed above, a repair which is closer to true regenerative healing of ligaments, and all soft tissues, may eventually be achieved.

Avaliação da resistência de suturas duodenais com ou sem omentoplastia pediculada: estudo experimental em ratas

Estudamos os efeitos da omentoplastia pediculada como método de reforço de suturas sobre o duodeno. Foram utilizadas 135 ratas HOLTZMAN, divididas em nove subgrupos de quinze ratas cada (n=15). Após a realização de uma lesão padronizada na segunda porção do duodeno, os animais, exceto os do grupo controle, foram submetidos, dependendo do subgrupo, a dois tipos diferentes de reparos: n sutura da lesão e omentoplastia pediculada de reforço. n sutura da lesão sem omentoplastia de reforço. A avaliação da resistência do reparo da lesão duodenal, foi realizada através da insuflação de ar até a ruptura do segmento testado. Esta avaliação foi feita em três períodos pós-operatórios diferentes: dois, sete e 14 dias em todos os subgrupos. O coeficiente de variação (CV) foi utilizado como forma de avaliar a variabilidade interna das variáveis centrais do estudo. Nos casos em que a análise indicou a existência de influência de algum fator ou de interações entre os fatores estudados, realizamos as comparações múltiplas de médias segundo o teste "Least Significant Difference" (LSD). Os achados mostraram que a realização de uma omentoplastia pediculada como reforço de um reparo sobre uma lesão padronizada do duodeno, quando comparado a uma simples sutura, não aumentou a resistência do reparo. Não importando o dia de pós-operatório em que o teste de resistência foi realizado. Os achados histológicos demonstraram que a omentoplastia pediculada proporcionou reação inflamatória intensa no nível do reparo.

Hyaluronic acid-based polymers as cell carriers for tissue-engineered repair of bone and cartilage

Culture-expanded bone marrow-derived mesenchymal progenitor cells differentiate into chondrocytes or osteoblasts when implanted subcutaneously in vivo in combination with an appropriate delivery vehicle. This in vivo implantation technique is used to test new materials as putative delivery vehicles in skeletal tissue-engineering models. HYAFF 11 and ACP sponges, two biomaterials based on hyaluronic acid modified by esterification of the carboxyl groups of the glucuronic acid, were tested as osteogenic or chondrogenic delivery vehicles for rabbit mesenchymal progenitor cells and compared with a well characterized porous calcium phosphate ceramic delivery vehicle. The implant materials were examined by scanning electron microscopy for differences in pore structure or cellular interactions, were quantified for their ability to bind and retain mesenchymal progenitor cells, and were examined histologically for their ability to support osteogenesis and chondrogenesis after subcutaneous implantation into nude mice. The ACP sponge bound the same number of cells as fibronectin-coated ceramic, whereas the HYAFF 11 sponge bound 90% more. When coated with fibronectin, ACP and HYAFF 11 bound, respectively, 100 and 130% more cells than the coated ceramics. HYAFF 11 sponge composites retained their integrity after the 3 or 6-week incubation period in the animals and were processed for histomorphometric analysis. As a result of rapid degradation or resorption in vivo, ACP sponges could not be recovered after implantation and could not be analyzed. HYAFF 11 sponges presented more area available for cell attachment and more available volume for newly formed tissue. Following loading with mesenchymal progenitor cells and implantation, the pores of the sponges contained more bone and cartilage than the pores of ceramic cubes at either time point. Thus, relative to ceramic, HYAFF 11 sponges allow incorporation of twice as many cells and produce a 30% increase in the relative amount of bone and cartilage per unit area. Hence, the hyaluronic acid-based delivery vehicles are superior to porous calcium phosphate ceramic with respect to the number of cells loaded per unit volume of implant, and HYAFF 11 sponges are superior to the ceramics with regard to the amount of bone and cartilage formed. Additionally, hyaluronic acid-based vehicles have the advantage of degradation/resorption characteristics that allow complete replacement of the implant with newly formed tissue.