Analysis of collagen-interacting proteins in patients with incisional hernias

Study of matrix metalloproteinase-2 in inguinal hernia

BACKGROUND

Abnormal collagen metabolism is thought to play an important role in the development of primary inguinal and ventral hernia. The detection of an impaired collagen balance both in the tissue as well as in cultured fibroblasts underlines the suspicion that the development of hernia is likely to be implemented primarily by a disturbance of the fibroblast function and their collagen genes. Based on these results we assume that the altered collagen synthesis in hernia patients can be regarded as a genetically linked deregulation serving as a basic initiating or promoting factor for the development of primary inguinal hernias. With the hypothesis that hernia is a local manifestation of a systemic disease manifested by increased expression of matrix metallo-proteinase-2 (MMP-2), a study was planned with following aims: 1) to establish a causal association between inguinal hernia and MMP-2; 2) to test the hypothesis that hernia is a local manifestation of a systemic disorder rather than a mere local mechanical defect.

METHODS

A case control study was conducted on 30 subjects of each direct and indirect inguinal hernia and 30 controls. DAC-ELISA test was used for analysis of serum (preoperative) and tissue samples (fascia transversalis) in patients as well as controls.

RESULTS

Statistically, serum levels of MMP-2 were significantly increased in all the hernia patients as compared to controls. This increment was maximum in patients of direct hernia. MMP-2 was not detectable in tissue samples.

CONCLUSIONS

Hernia is a local manifestation of a systemic disease rather than a mere local mechanical defect.

KEYWORDS

MMP-2; Matrix Metalloproteinase-2; Inguinal hernia; DAC-ELISA; Collagen metabolism; PBST-Phosphate Buffer Saline Tween-20.

Impact of mesh positioning on foreign body reaction and collagenous ingrowth in a rabbit model of open incisional hernia repair

BACKGROUND

Incisional hernia remains as one of the most common surgical complications. Different mesh techniques are used in 75-80% of hernia repair. The aim of this study was to evaluate the dependence of mesh positioning and the type of mesh implanted on foreign body reaction and collagenous ingrowth.

MATERIALS AND METHODS

In 24 male Chinchilla rabbits, an incisional hernia repair was performed with mesh reinforcement either by sublay (n = 12) or by onlay technique (n = 12). In each group, two different types of mesh prosthesis were investigated: polypropylene (PP, Prolene) and polypropylene-polyglecaprone 25 composite (PP-PG, UltraPro). On postoperative day 60, the inflammatory and connective tissue formation was characterised by measuring the diameter of inner cellular infiltrate and outer fibrous capsule of the foreign body granuloma, and by verifying the collagen type I/III ratio. Furthermore, the expression of matrix metalloproteinase-2 (MMP-2) was analysed.

RESULTS

Microscopic investigation of the mesh/host-tissue interface showed typical formation of foreign body granuloma. The diameters of the inner part of the foreign body granuloma representing the amount of inflammatory cell infiltrate were significantly increased in the PP mesh compared to the PP-PG mesh, both in the sublay group (PP 13.1 +/- 1.21 microm vs. PP-PG 11.7 +/- 0.34 microm; P = 0.026) and in the onlay group (PP 13.1 +/- 1.24 microm vs. PP-PG 11.2 +/- 0.55 microm; P = 0.009). The diameter of the fibrous capsule as the outer ring of the granuloma was significantly increased when investigating the PP mesh in sublay position (29.5 +/- 1.12 microm) compared to the PP mesh in onlay position (27.9 +/- 0.73 microm) (P = 0.026). Investigating the quality of perifilamentary collagen deposition expressed as collagen type I/III ratio, the sublay group showed significantly elevated values compared to the onlay group (PP sublay 3.1 +/- 0.18 vs. PP onlay 2.4 +/- 0.41; P = 0.004) (PP-PG sublay 3.5 +/- 0.34 vs. PP-PG onlay 2.6 +/- 0.13; P = 0.002). The analysis of MMP-2 expression revealed no significant differences.

CONCLUSION

The beneficial results of mesh reinforcement in the sublay technique might be due to a superior quality of postoperative connective tissue formation. Mesh incorporation, irrespective of positioning, is favourable in low-weight, large, porous mesh material represented by a reduced inflammatory part of the foreign body granuloma.

The role of matrix metalloproteinases in the pathogenesis of abdominal wall hernias

Surgical treatment of abdominal wall hernia has been based for many decades on observational evidence, as the disease physiopathology was ambiguous. The long-standing hypothesis of abnormal collagen metabolism as a causative factor of hernia disease seems to become substantiated by modern investigations, demonstrating a link between abnormal matrix metalloproteinase (MMP) expression and abdominal wall hernia. Current evidence suggests a strong correlation between MMP-2 and direct inguinal hernia, while the role of this MMP in indirect, incisional and recurrent hernias has not been completely elucidated yet. Furthermore, MMP-1 and MMP-13 seem to be implicated in the physiopathology of recurrent hernia, while limited data link MMP-1 also with incisional hernia formation. Despite the importance of MMP-9 in wound healing mechanisms, its role in hernia pathogenesis has not been adequately investigated. Future research is expected to decipher the complex physiopathological mechanisms of hernia development and provide a basis for potential therapeutic applications.

Delayed wound healing in sacrococcygeal pilonidal sinus coincides with an altered collagen composition

BACKGROUND

Although patients with pilonidal sinus are young and, thus, are expected to heal well, a delayed healing with high risk of recurrence frequently is observed. This study was initiated to test whether disorders in the extracellular matrix (ECM) may be detected in patients with pilonidal sinus and delayed wound healing or recurrent disease, respectively.

METHODS

In 48 patients, tissue specimens were obtained at the index operation. All patients were treated by local excision and primary wound closure. The collagen type I/III ratio, the expression of matrix metalloproteinase (MMP)-1, -9, and -13, as well as the proliferation index (Ki67) and the macrophage infiltrate (CD68) were measured. Patients with an uneventful wound healing by primary intention were compared with those in which the healing by primary intention fails (secondary healing), and patients suffering first onset of pilonidal sinus or to those patients who had undergone previous surgery for pilonidal sinus. Clinical parameters and comorbidity were evaluated.

RESULTS

Patients with secondary healing, exhibited at the index operation a significantly lower collagen type I/III ratio (2.34+/-0.4) compared with patients with problem-free wound healing (3.04+/-0.7). Furthermore, significantly higher expression of MMP-1, -9, and 13, and a significantly higher proliferation index (Ki67) were found in the specimens of the patients with secondary healing. In patients in whom the operation was performed because of a recurrence expression of both Ki67 and CD68 were significantly higher. Smokers had an increased risk for suffering recurrent disease, but did not show differences in the collagen ratio.

CONCLUSIONS

As a novel finding, this study indicates that disturbances of the ECM may predict a delayed wound healing after pilonidal sinus surgery.

Laparoscopic parastomal hernia repair using a keyhole technique results in a high recurrence rate

INTRODUCTION

Parastomal herniation is a common complication of stoma formation, and its operative treatment is notoriously difficult. Recently we have reported the promising short-term results of a keyhole technique in which a Gore-Tex Dual Mesh with a central keyhole is laparoscopically fashioned around the bowel to close the hernia. In the long-term, recurrence is one of the major issues in hernia repair, therefore, this aspect was prospectively investigated.

METHODS

Since 2002, a total of 55 consecutive patients (27 men; median age, 63 years) with a symptomatic primary (n = 45) or recurrent parastomal hernia (n = 10) were electively operated using this technique. Patients were invited to the outpatient clinic on a regular basis and were examined for the occurrence of a recurrent hernia. At the last visit, all patients were asked to complete a short questionnaire.

RESULTS

Median follow-up (98%) was 36 (range, 12-72) months. During follow-up a recurrent parastomal hernia was diagnosed in 20 patients (37%). Three recurrences were asymptomatic and were treated conservatively. The other 17 patients (85%) developed mild-to-severe symptoms necessitating redo-surgery in 9 (45%) patients. Surprisingly, satisfaction with the procedure was high among patients (89%), even in the presence of a recurrence. Patients who reported unsatisfactory results belonged mainly to the group in whom the initial laparoscopic approach had to be converted to an open procedure.

CONCLUSIONS

Based on the results from the present study, which represents one of the largest patient series with the longest follow up available to date, it is concluded that laparoscopic parastomal hernia repair using a keyhole technique has an intolerably high recurrence rate with the currently available meshes. A new mesh with a less pliable central part and without the tendency to shrink is awaited.

MMPs/TIMPs and inflammatory signalling de-regulation in human incisional hernia tissues

Background: Incisional hernia is a common and important complication of laparotomies. Epidemiological studies allude to an underlying biological cause, at least in a subset of population. Interest has mainly focused on abnormal collagen metabolism. However, the role played by other determinants of extracellular matrix (ECM) composition is unknown. To date, there are few laboratory studies investigating the importance of biological factors contributing to incisional hernia development. We performed a descriptive tissue-based analysis to elucidate the possible relevance of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in association with local cytokine induction in human incisional hernia tissues. The expression profiles of MMPs, TIMPs and pro-inflammatory cytokine signalling were investigated in aponeurosis and skeletal muscle specimens taken intraoperatively from incisional hernia (n= 10) and control (n= 10) patients. Semiquantitative RT-PCR, zymography and immunoblotting analyses were done. Incisional hernia samples displayed alterations in the microstructure and loss of ECM, as assessed by histological analyses. Moreover, incisional hernia tissues showed increased MMP/TIMP ratios and de-regulated inflammatory signalling (tumor necrosis factor [TNFA] and interleukin [IL]-6 tended to increase, whereas aponeurosis TNFA receptors decreased). The changes were tissue-specific and were detectable at the mRNA and/or protein level. Statistical analyses showed several associations between individual MMPs, TIMPs, interstitial collagens and inflammatory markers. The increment of MMPs in the absence of a counterbalance by TIMPs, together with an ongoing de-regulated inflammatory signalling, may contribute in inducing a functional defect of the ECM network by post-translational mechanisms, which may trigger abdominal wall tissue loss and eventual rupture. The notable TIMP3 protein down-regulation in incisional hernia fascia may be of pathophysiological significance. We conclude that this study may help to pinpoint novel hypotheses of pathogenesis that can lead to a better understanding of the disease and ultimately to improvement in current therapeutic approaches.

Laparoscopic versus open ventral hernia repair

Ventral hernia repair remains one of the most common operations performed by general surgeons. Despite the frequency with which this procedure is performed, there is little agreement and extensive controversy as to the cause of most of the hernias, or the ideal approach to repair these complicated problems. This article attempts to identify and provide some clarification of these controversial issues in abdominal wall reconstruction after ventral herniation based on the available literature.

Fibrillin-1 in incisional hernias: an immunohistochemical study in scar and non-scar regions of human skin and muscle fasciae

Incisional hernias represent one of the most common complications after laparotomy. Specific pre-operative risk factors have not yet been identified. Recent studies indicate that changes in extracellular matrix components such as collagen I and collagen III may be involved in hernia development. In the present study we have evaluated the significance of fibrillin-1 in hernia development as one of the main components of the extracellular matrix. Tissue samples from non-scar skin and muscle fascia of 12 patients with incisional hernias as well as from the respective scar tissues were obtained. Corresponding tissue samples of 10 patients with normal postoperative wound healing served as controls. Distribution of fibrillin-1 was evaluated immunohistochemically. Differences in fibrillin-1 distribution in the non-scar tissues of muscle fascia have been found in patients with incisional hernia, compared to those without hernia. In scar regions of both patient groups, slight differences in the pattern of fibrillin-1 were observed. A tendency to a differential deposition of fibrillin-1 in skin samples, although hardly quantifiable, was observed as well. Our results suggest that fibrillin-1 is a relevant factor contributing to tissue stability. Disturbances in its deposition, even before scar formation, may be an important factor to the development of incisional hernias.

The biology of hernia formation

Abdominal wall hernias occur when tissue structure and function are lost at the load-bearing muscle, tendon, and fascial layer. The fundamental biologic mechanisms are primary fascial pathology or surgical wound failure. In both cases, cellular and extracellular molecular matrix defects occur. Primary abdominal wall hernias have been associated with extracellular matrix diseases. Incisional hernias and recurrent inguinal hernias more often involve a combination of technical and biologic limitations. Defects in wound healing and extracellular matrix synthesis contribute to the high incidence of incisional hernia formation following laparotomy.

Abnormal Primary Tissue Collagen Composition in the Skin of Recurrent Incisional Hernia Patients

Recurrence of incisional hernia may be as high as 50 per cent. Abnormal collagen I/III ratios have been observed within scar tissue of patients with recurrent incisional hernias. We sought to determine whether collagen composition in primary, nonscarred tissue was similarly affected in these patients. In this prospective, case–control study, nonscarred, primary abdominal wall skin and fascia biopsies were obtained in 12 patients with a history of recurrent incisional hernias and 11 control subjects without any history of hernia while undergoing abdominal laparoscopic surgery. Tissue protein expression of collagen I and III was assessed by immunohistochemistry followed by densitometry analysis. The collagen I/III ratio in skin biopsies from the recurrent hernia group was significantly less compared with control subjects (0.88 ± 0.01 versus 0.98 ± 0.04, respectively, P < 0.05). Fascia biopsies from patients with recurrent hernias was not significantly decreased in collagen I/III ratio compared with control subjects (0.90 ± 0.04 versus 0.94 ± 0.03, respectively, P = 0.17). Decreased collagen I/III ratios within the skin of patients with recurrent hernias not involved with scar or healing tissue suggest an underlying collagen composition defect. Such a primary collagen defect, in addition to abnormal scar formation, likely plays a significant role in the pathogenesis of recurrent incisional hernias.

Are collagens the culprits in the development of incisional and inguinal hernia disease?

Incidence curves for the development of inguinal hernia disease and recurrences thereof exhibit a linear rise over the years and therefore suggest multi-factorial underlying causes. Several studies have revealed marked changes in the abundance and composition of interstitial collagens in patients with (recurrent) hernia diseases, adult groin hernia and incisional hernia. These observations led to the hypothesis that hernia formation and the recurrence of incisional hernia may be explained by disordered tissue renewal and by abnormal wound healing, respectively. Interstitial collagens, owing to their long half-lives and biomechanical strength, are most likely critical components of the biological system of tissue remodelling. An overview of the literature is provided, and the consequences for surgical practice are discussed.

Biomechanical analyses of overlap and mesh dislocation in an incisional hernia model in vitro

BACKGROUND

Incisional hernia repair is one of the most common surgical complications. Despite the introduction of mesh techniques of repair, recurrences are still prevalent. The aim of the current study was to evaluate the dependence of mesh dislocation on defect size, facial overlap, mesh-position, and orientation of the mesh in cases of anisotropic stretchability.

METHODS

An in vitro incisional hernia model was used, which consisted of a pressure chamber, an elastic silicone pad representing the peritoneal sac, and a silicone mat with bovine muscle tissue representing the abdominal wall. Intrinsic pressure (up to 200 mm Hg) was generated within the pressure chamber by continuous inflation with CO(2). A slit-like or flap-like defect was created in the silicone mat to simulate small or large hernia defects, respectively. The implanted mesh was arranged in both onlay and sublay configurations. A large pore polypropylene mesh with significant anisotropic stretchability was investigated, whereas overlaps of 2, 3, and 4 cm were applied.

RESULTS

Despite the application of pressures up to 200 mm Hg, no mesh ruptures occurred. In the slit-like defect model, the minimal overlap required to prevent dislocation at 200 mm Hg was 3 cm using the sublay technique provided that the mesh was positioned with its most stretchable axis parallel to the largest slit dehiscence. Perpendicular rotation of the mesh resulted in dislocation at 160 mm Hg, despite using an overlap of 3 cm. Mesh reinforcement showed less stability in both the onlay position and the flap-like defect.

CONCLUSION

An overlap of 3 cm is sufficient to prevent early mesh dislocation. Meshes with anisotropic stretchability should be orientated with the most stretchable axis in the direction of least overlap.

Collagen metabolism and recurrent hiatal hernia: cause and effect?

Hiatus hernia (HH) is a condition characterized by herniation of the intra-abdominal organs into the thorax. Of the several types that have been identified, the most common is type I (sliding) HH. Congenital predisposition and acquired factors, for example trauma and iatrogeny, have been identified as causative factors. There is a strong association between gastroesophageal reflux disease and HH-the prevalence of reflux in HH may reach 94%. Many methods have been used to treat reflux disease and HH, among which are laparoscopic techniques, which gained popularity as a safe method of treatment. Primary crural repair without mesh application was found to have a recurrence rate of up to 42%. This led to the introduction of mesh in HH repair, which was associated with a significant decrease in recurrence rate. Collagen and its relation to hernia have been investigated for several decades. Collagen has mechanical properties sufficient to enable it to support healed scars and other tissues. Nineteen distinct types of collagen have been recognized, the most common of which are types I and III. Type III collagen is the major constituent of early granulation tissue whereas type I predominates as healing proceeds. Collagen fibers are imbedded in extracellular matrix (ECM), which is in continuous process of synthesis and degradation under the action of matrix metalloproteinases. Many authors have studied the role of collagen in ventral hernia and have even defined hernia as a disease of the ECM. The relationship between collagen and HH, and its recurrence, is not fully understood and needs further investigation.

The biology of hernias and the abdominal wall

The fundamental mechanism for hernia formation is loss of the mechanical integrity of abdominal wall structural tissue that results in the inability to offset and contain intra-abdominal forces during valsalva and loading of the torso. There is evidence that genetic or systemic extracellular matrix disorders may predispose patients to hernia formation. There is also evidence that acute laparotomy wound failure leads to hernia formation and increases the risk of recurrent hernia disease. It may be that hernia formation is a heterogeneous disease, not unlike cancer, where one population of patients express an extracellular matrix defect leading to primary hernia disease, while other subsets of patients acquire a defective, chronic wound phenotype following failed laparotomy and hernia repairs. It is evident that an improved understanding of structural tissue matrix biology will lead to improved results following abdominal wall reconstructions.

Role of Biomarkers in Incisional Hernias

Incisional hernias represent one of the most common complications of laparotomies. Previous investigations have suggested that a disorder in collagen fiber structure and production level may be an important pathologic cause of abdominal wall hernias. We hypothesized that a cross-examination of multiple extracellular matrix biomarkers might identify underlying defects contributing to the development of hernias. We examined two patient populations: patients with incisional hernias (presenting for hernia repair) and patients with no hernia after previous laparotomy (undergoing a second laparotomy). Patients with previous wound infections, open abdomens, or on steroids were excluded. Fascia samples were obtained from all patients at the time of their second operation and they were studied. Western blots and reverse transcriptase-polymerase chain reaction were used to determine the ratio of type I, III, and IV collagens, as well as matrix metalloproteinase 1 (MMP1) and MMP2 in both groups. Values of P < 0.05 were considered statistically significant. At the protein level, collagen I/III ratio was slightly decreased in patients with incisional hernias compared with those with no hernia, whereas it was significantly decreased at the mRNA transcript level (0.49 vs 1.03, P < 0.01, respectively). The MMP-1 mRNA transcripts were not different in incisional hernia (IH) versus nonincisional hernia, but the MMP-2 level was significantly increased in patients with IH. Reduced collagen I/III and MMP-1/MMP-2 ratios in IH might be consequence of the biological activities between key elements participating in the development of IH after laparotomies. The potential role of MMP-2–specific inhibitors in preventing IH is of significance for future studies.

Laparoscopic parastomal hernia repair is feasible and safe: early results of a prospective clinical study including 55 consecutive patients

BACKGROUND

Parastomal herniation is a common complication, and its operative treatment is notoriously difficult. Recently, the authors have described a laparoscopic technique for closure and reinforcement of the hernia with a hand-made "funnel-shaped" Gore-Tex Dual Mesh. Potentially this technique combines the advantages of a mesh repair with those of minimal invasive surgery.

METHODS

In 2002, a multicenter trial of this new technique was started in The Netherlands. To date, 55 consecutive patients (27 men; median age, 63 years) with a symptomatic primary (n = 45) or recurrent (n = 10) parastomal hernia have undergone elective surgery using this technique. The demographic, perioperative, and early follow-up data prospectively collected for these patients are presented in this report.

RESULTS

Of the 55 procedures, 47 (85.5%) could be completed laparoscopically (median operation time, 120 min). Conversion to laparotomy was indicated because of dense adhesions prohibiting safe dissection (n = 4) or bowel injury (n = 4). No in-hospital mortality occurred. Postoperative recovery was uneventful for 47 patients (85%), who had a median hospital stay of 4 days. Surgical and nonsurgical complications occurred, respectively, for four patients each (7.2%). Full-thickness enterotomy appeared to be the most troublesome complication. After 6 weeks, when all the patients were reexamined, one recurrence was noted.

CONCLUSION

Maximal efforts should be undertaken to prevent perioperative full-thickness enterotomy. Because this was achieved for the vast majority of patients, it is concluded that laparoscopic parastomal hernia repair is feasible and safe. Although a longer follow-up period is needed for definitive conclusions to be drawn regarding the recurrence rate, early follow-up evaluation shows very promising results.

Primary incisional hernia repair with or without polypropylene mesh: a report on 384 patients with 5-year follow-up

BACKGROUND AND AIM

Several studies have claimed that mesh repair of incisional hernia lowers recurrence rates when compared to suture repair. We investigated the relative effectiveness of mesh and suture repair in a large homogeneous cohort of patients with primary incisional hernia.

PATIENTS AND METHODS

In a retrospective single-centre cohort study, a total of 446 consecutive patients were identified, of whom 86% could be followed up. Mean length of follow-up was 5 years. In 79 patients (22%), we implanted a mesh, usually polypropylene (Prolene).

RESULTS

Compared to suture repair, mesh repair prolonged operating time by over 30 min and caused seroma in 12.7% of the patients (p<0.001). Only 4 of the 79 patients with mesh repair developed recurrence, compared to 55 of the 305 patients with suture repair (5 vs 18%, p=0.02 by log-rank test). In multivariate Cox regression, recurrence rates were fourfold higher after suture than after mesh repair (p=0.02). Interestingly, old age was associated with a decreased susceptibility for recurrence (p=0.01).

CONCLUSION

Our data confirms the long-term effectiveness of mesh repair under routine conditions. Suture repair should be restricted to small hernias in patients free of known risk factors.

Hiatal hernia recurrence: 2004

BACKGROUND

The incidence of laparoscopic hiatal hernia recurrence is less than ideal. The reasons are more theoretical than objective, as the literature has little data in support of specific mechanisms of recurrence.

METHOD

A recent literature review using all Internet-available, English-language articles on laparoscopic hernia repair was completed.

RESULTS

A multitude of mechanisms of recurrence are suggested, but only surgeon inexperience, postoperative vomiting, heavy lifting, and retention of the hernia sac are supported by data.

CONCLUSION

The incidence of hiatal hernia recurrence has stabilized. The role of an onlay mesh prosthesis for the prevention of hiatal hernia recurrence is under investigation, and long-term results are awaited.

[Prevention of median incisional hernia in rats by ultrasonic therapy]

PURPOSE

To investigate if ultrasonic therapy is effective in avoidance of incisional hernia (IH), once the ideal technique for repair of IH is still a non-solved problem, in despite of prostheses usage.

METHODS

IH was created by linea alba opening over 20 male Wistar rats, distributed in two groups: one group received the ultrasound, over the wound, during 14 days (5 animals) and the other for 28 days (5 animals), each one with the same number of animals as controls. The ultrasound was applied using a small probe, 1:5 pulse mode, 3.0 MHz frequency and 0.5W/cm2 intensity, for 5 minutes daily, from the first postoperative day. The width of the linea alba scar or the hernia ring was measured at the end of every period. The IH was defined when these openings were over 2mm wide. Some specimens from hernia sac or linea alba scar were obtained for vessels, fibroblasts, and colagen fibers density. Standard deviation and medians were obtained by variation analysis and Tukey-Kramer multi-comparison test.

RESULTS

The ultrasound group showed a linea alba scar in 60%. The other 40% presented the hernia ring smaller than the non treated group (p < 0.0001). The ultrasound increased density of blood vessels (p = 0.0031), fibroblasts (p < 0.0001), and collagen fibers (p = 0.0015). There was no difference between the two treated groups.

CONCLUSION

The ultrasound avoided the IH to appear or reduced its width. Fourteen days of treatment were sufficient for this purpose.

Changes of the extracellular matrix as a risk factor for anastomotic leakage after large bowel surgery

BACKGROUND

Despite improved surgical techniques, anastomotic leakage remains as a serious complication in colorectal surgery, producing increased morbidity and mortality. This prospective study was initiated to test the hypothesis that preexisting disorders in the extracellular matrix (ECM) may be a factor influencing the onset of anastomotic wound healing complications.

METHODS

In this prospective study of 119 patients with colorectal anastomoses, 30 clinical parameters with possible influence on anastomotic complications were evaluated. From all patients, samples of macroscopically intact colonic tissue were obtained at the index operation. Crosspolarization microscopy was performed to analyze the collagen type I/III ratio, and immunohistochemical studies were done to determine the expression of matrix metalloproteinase (MMP) 1, 2, 9, and 13. The patients with uncomplicated postoperative healing were compared with those developing anastomotic leakage.

RESULTS

Patients with impaired anastomotic healing exhibited a significantly lower collagen type I/III ratio compared with the controls. Significantly higher expression of MMP-1 and MMP-2 in the mucosal layers and of MMP-2 and MMP-9 in the submucosal layers was found in the normal bowel wall of the leakage group. These findings were statistically independent from the clinical parameters.

CONCLUSION

The present study confirms the hypothesis that disturbances of the ECM play a role in the pathogenesis of anastomotic leakage after large bowel surgery.

Efeito do ultra-som na prevenção da hérnia incisional mediana em ratos

OBJETIVO: Investigar se o ultra-som é capaz de evitar o aparecimento da hérnia incisional (HI), uma vez que o seu tratamento ainda é um problema não resolvido. MÉTODO: Induziu-se a HI, por secção da linha alba, em 20 ratos Wistar, distribuídos em dois grupos: um recebeu a aplicação do ultra-som, na área operada, por 14 dias e o outro por 28 dias, cada qual com seu subgrupo controle (não tratado). Utilizou-se aparelho com cabeçote reduzido, modo pulsado (1:5), freqüência de 3,0MHz e intensidade de 0,5W/cm², durante 5min/dia, iniciando-se as aplicações no primeiro dia pós-operatório. Ao final, mediu-se o diâmetro transverso do anel herniário ou da largura da cicatriz na linha alba, definindo-se a HI quando esses valores ultrapassassem 2mm. A densidade de vasos sangüíneos, de fibroblastos e de fibras colágenas, nessas estruturas, foi estudada à microscopia óptica. As médias e o erro padrão foram submetidos à análise de variância (ANOVA) e ao teste de comparação múltipla de Tukey-Kramer. RESULTADOS: Dos animais tratados com o ultra-som, 60% não desenvolveram HI e, nos restantes, o anel herniário foi menor do que os não tratados (p<0,0001). A densidade de vasos sangüíneos (p=0,0031), de fibroblastos (p<0,0001) e de fibras colágenas (p=0,0015) também foi maior, em relação aos controles. Não houve diferença significante nesses parâmetros, comparando-se os dois períodos de tratamento. CONCLUSÃO: O ultra-som evitou o aparecimento da HI ou reduziu o seu tamanho, quando aplicado por 14 dias pós-operatórios, nas condições deste experimento.

Collagen synthesis is not altered in women with stress urinary incontinence

AIMS

The objective of this study was to demonstrate that weakened pelvic floor support of the lower genitourinary tract in women with stress urinary incontinence (SUI) is due, in part, to decreased collagen synthesis and secretion and/or an altered ratio of collagen III/I synthesis by the fibroblasts of the endopelvic fascia and skin compared to that of women without evidence of pelvic floor weakening.

METHODS

Endopelvic fascia and skin biopsies were obtained from women with SUI (n = 14) and women without evidence of SUI or genital prolapse (n = 12). Fibroblast cultures established from the biopsies were incubated with 3H-proline in medium containing ascorbic acid for 3 hr. Conditioned medium was collected and cells were harvested. The radiolabeled collagens were precipitated and digested with collagenase. The collagen synthesized (as a percent of total protein) was determined. Collagen alpha1(III) was separated from collagen alpha1(I) and alpha2(I) by interrupted SDS-PAGE and the amount of (3)H-proline in each band was determined.

RESULTS

Collagen synthesis, expressed as percent of total protein synthesis, was not significantly different between fibroblasts obtained from women with or without SUI. The mean of collagen III/I synthesized in fibroblasts was not significantly different between fibroblasts obtained from women with or without SUI.

CONCLUSIONS

These data suggest that the lower collagen content in the endopelvic fascia and skin of women with SUI is not due to reduced collagen synthesis or selective reduction in synthesis of either collagen I or collagen III, compared to women without pelvic floor weakening.