Collagenase and surgical disease

Characteristics of cell adhesion molecules expression and environmental adaptation in yak lung tissue

Cell Adhesion Molecules (CAMs) play a crucial role in regulating immune responses and repairing damage caused by hypoxia. However, the relationship between the expression characteristics of CAMs in yak lung tissues and their adaptation to the plateau environment remains unclear. To address this question, we compared lung tissues from yaks and cattle at the same altitude. After digesting the lung tissues with trypsin or Type I collagenase for varying durations, we observed that fewer cells were isolated from yak tissues compared to cattle. RNA sequencing (RNA-seq) analysis revealed that the Differentially Expressed Genes (DEGs) in lung tissues of yaks and cattle were significantly enriched in cell adhesion-related pathways. Quantitative real-time PCR (qRT-PCR) further identified changes in the expression levels of five distinct types of CAMs. Among these, the cadherin family (CDH1, CDH2, CDH11, PCDH12, CD34) exhibited significantly higher expression in yaks than in cattle. These cadherins play a critical role in regulating lung inflammation and maintaining the alveolar-capillary barrier, thereby ensuring the structural stability of the lungs. Immunohistochemical staining demonstrated that the expression patterns of cell adhesion-related proteins (CDH1, CDH11, ITGB6, SELP, CD44) were largely consistent with the qRT-PCR results. In conclusion, compared to cattle, the enhanced cell adhesion capacity of yak lung tissues contributes to their superior adaptation to the harsh plateau environment.

Thermostable Bacterial Collagenolytic Proteases: A Review

Collagenolytic proteases are widely used in the food, medical, pharmaceutical, cosmetic, and textile industries. Mesophilic collagenases exhibit collagenolytic activity under physiological conditions, but have limitations in efficiently degrading collagen-rich wastes, such as collagen from fish scales, at high temperatures due to their poor thermostability. Bacterial collagenolytic proteases are members of various proteinase families, including the bacterial collagenolytic metalloproteinase M9 and the bacterial collagenolytic serine proteinase families S1, S8, and S53. Notably, the C-terminal domains of collagenolytic proteases, such as the pre-peptidase C-terminal domain, the polycystic kidney disease-like domain, the collagen-binding domain, the proprotein convertase domain, and the β-jelly roll domain, exhibit collagen-binding or -swelling activity. These activities can induce conformational changes in collagen or the enzyme active sites, thereby enhancing the collagen-degrading efficiency. In addition, thermostable bacterial collagenolytic proteases can function at high temperatures, which increases their degradation efficiency since heat-denatured collagen is more susceptible to proteolysis and minimizes the risk of microbial contamination. To date, only a few thermophile-derived collagenolytic proteases have been characterized. TSS, a thermostable and halotolerant subtilisin-like serine collagenolytic protease, exhibits high collagenolytic activity at 60°C. In this review, we present and summarize the current research on A) the classification and nomenclature of thermostable and mesophilic collagenolytic proteases derived from diverse microorganisms, and B) the functional roles of their C-terminal domains. Furthermore, we analyze the cleavage specificity of the thermostable collagenolytic proteases within each family and comprehensively discuss the thermostable collagenolytic protease TSS.

Relationship Between the Changes of Tendon Elastic Moduli With Ultrasound Shear Wave Elastography and Mechanical Compression Test

OBJECTIVE

The purpose of this study was to investigate the consistency of the changes in the elastic modulus measured with ultrasound shear wave elastography (SWE) with changes measured through mechanical testing using tendons that were artificially altered by chemical modifications.

METHODS

Thirty-six canine flexor digitorum profundus tendons were used for this experiment. To mimic tendon mechanical property changes induced by tendinopathy conditions, tendons were treated with collagenase to soften the tissue by collagen digestion or with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) to stiffen the tissues through chemical crosslinking. Tendons were randomly assigned to one of three groups: immersion in phosphate-buffered saline (PBS) as a control group (n = 12), collagenase treatment (n = 12) or EDC treatment (n = 12). Immediately following SWE measurement of each tendon, mechanical compression testing was performed as a gold standard to validate the SWE measurement. Both tests were conducted before and after treatment.

RESULTS

The compressive modulus and SWE shear modulus significantly decreased after collagenase treatment. Conversely, both moduli significantly increased after EDC treatment. There was no significant difference in either modulus before or after PBS treatment. As a result of a regression analysis with the percentage change of the compressive modulus as the dependent variable and SWE shear modulus as the independent variable, the best-fit regression was found to be an exponential function and the coefficient of determination was 0.687.

CONCLUSION

The changes in the compressive moduli and SWE shear moduli in tendons induced by chemical treatments were correlated by approximately 70%.

Biomimetic polyelectrolyte coating of stem cells suppresses thrombotic activation and enhances its survival and function

Mesenchymal stem cells (MSCs) therapy is a promising approach for treating inflammatory diseases due to their immunosuppressive and tissue repair characteristics. However, allogenic transplantation of MSCs induces thrombotic complications in some patients which limits its potential for clinical translation. To address this challenge, we have exploited the bioactivity of heparin, a well-known anticoagulant and immunosuppressive polysaccharide that is widely used in clinics. We have developed a smart layer-by-layer (LbL) coating strategy using gelatin and heparin polymers exploiting their overall positive and negative charges that enabled efficient complexation with the MSCs' glycocalyx. The stable coating of MSCs suppressed complement attack and mitigated thrombotic activation as demonstrated in human whole blood. Gratifyingly, the MSC coating retained its immunosuppressive properties and differentiation potential when exposed to inflammatory conditions and differentiation factors. We believe the simple coating procedure of MSCs will increase allogenic tolerance and circumvent the major challenge of MSCs transplantation.

Shear wave elastography imaging in a porcine tendinopathy model

OBJECTIVE

To quantify the effect of structural damage in an ex vivo animal tendinopathy model using shear wave elastography (SWE).

MATERIALS AND METHODS

Sixteen porcine flexor tendons were injected with a 0.05 mL bolus of 1.5% collagenase solution to induce focal structural damage without surfacing tears. Control tendons were injected with saline (n = 16). Eight tendons from each group were incubated at 37 °C for 3.5 h while the remaining 8 from each group were incubated for 7 h. Tendons were mechanically stretched to 0% and 1% strain. Simultaneously, SWE was acquired proximal to, at, and distal to the injection site using a clinical ultrasound scanner.

RESULTS

There were significant differences in SWS (saline > collagenase) at 1% strain and 7-h incubation for all three locations (PROX p = 0.0031, ROI p = 0.001, DIST p = 0.0043). There were also significant differences at 0% strain and 7 h, but only at (p = 0.0005), and distal to (p = 0.0035), the injection site. No statistically significant differences were observed for 3.5-h incubation, at 0% or 1% strain.

CONCLUSIONS

Collagenase-mediated structural damage does appear to convey decreased tissue elasticity on SWE when ex vivo tendons are incubated for 7 h. These findings suggest that SWE may be a useful tool for predicting ultimate tissue strength in tendinopathic tissues. Pull-to-failure testing should be performed in the future and are expected to show that tendons with decreased SWS, and, therefore, decreased elasticity, rupture at lower pulls forces.

Molecular characterization of matrix metalloproteinase gene family across primates

Deregulation of matrix metalloproteinases (MMPs) contributes considerably to cancers, psychiatric disorders, macular degeneration and bone diseases. The use of humans in the development of MMPs as prognostic biomarkers and therapeutic targets is complicated by many factors, while primate models can be useful alternatives for this purpose. Here, we performed genome-enabled identification of putative MMPs across primate species, and comprehensively investigated the genes. Phylogenetic topology of the MMP family showed each type formulates a distinct clade, and was further clustered to classes, largely agreeing with classification based on biochemical properties and domain organization. Across primates, the excess of candidate sites of positive selection was detected for MMP-19, in addition to 1-3 sites in MMP-8, MMP-10 and MMP-26. MMP-26 showed Ka/Ks value above 1 between human and chimpanzee copies. We observed two copies of MMP-19 in the old-world monkey genomes, suggesting gene duplication at the early stage of or prior to the emergence of the lineage. Furin-activatable MMPs demonstrate the most variable properties regarding Domain organization and gene structure. During human aging, MMP-11 showed gradually decreased expression in testis, so as MMP-2, MMP-14, MMP15 and MMP-28 in ovary, while MMP-7 and MMP-21 showed elevated expression, implying their distinct roles in different reproductive organs. Co-expression clusters were formed among human MMPs both within and across classes, and expression correlation was observed in MMP genes across primates. Our results illuminate the utilization of MMPs for the discovery of prognostic biomarkers and therapeutic targets for aging-related diseases and carry new messages on MMP classification.

Matrix Metalloproteinase-2, COL1A1, and COL3A1 mRNA Expression in Aponeurosis Musculus obliquus Externus Abdominis of Adult Inguinal Hernias

BACKGROUND: The ratio change of type I and type III collagen in the peritoneal tissue can be associated with defects in collagen synthesis caused by the extracellular matrix’s degradation. Matrix metalloproteinase-2 (MMP-2) is an enzyme that contributes primarily to the degradation of this extra cell. AIM: This study aimed to analyze the differences in expression of COL1A1, COL3A1, and MMP-2 mRNA and the relationship between these expressions in adult inguinal hernias and the expression ratio between the COL1A1/COL3A1 genes. METHODS: This study was an observational study with a cross-sectional comparative study design, where the sample was adult inguinal hernia patients who were taken from the aponeurosis tissue m. external obliquus performed at the time of surgery, while control was a non-herniated patient. The sample RNA was isolated, followed by cDNA synthesis, and examined by real-time polymerase chain reaction. RESULTS: The mean values of expression for COL1A1, COL3A1, and MMP-2 in the case group were 40.02 ± 181.38 copy number, 33.70 ± 143.62 copy number, and 31.78 ± 84.47 copy number. Meanwhile, the expression values for COL1A1, COL3A1, and MMP-2 in the control group were 40.247 ± 162.837 copy number, 13.35 ± 37.43 copy number, and 20.58 ± 48.95 copy number. CONCLUSIONS: Our study showed a difference in COL3A1 expression between the hernia and non-hernia groups, and no difference was found in the expression of COL1A1 and MMP2 between the hernia and non-hernia groups.

Abdominal aortic aneurysms and abdominal wall hernias - a systematic review and meta-analysis

Background: Abdominal wall hernias (AWHs) share common epidemiological characteristics with abdominal aortic aneurysms (AAAs), typically presenting in male population and older ages. Prior reports have associated those two disease entities. Our objective was to perform a systematic review and meta-analysis and examine whether AAA rates are higher among patients with AWH vs controls and whether the incidence of AWH was higher among patients with AAA vs patients without AAA. Methods: We performed a systematic review and meta-analysis according to the PRISMA guidelines. The Medline database was searched up to July 31, 2020. A random effects meta-analysis was performed. Results: In total, 17 articles and 738,972 participants were included in the systematic review, while 107,578 patients were eligible for the meta-analysis. Among four studies investigating the incidence of AAA in patients with hernias, AAA was more common in patients with hernias, compared to patients without hernias. [OR: 2.53, 95% CI: 1.24-5.16, I²=81.6%]. Among thirteen studies that compared patients with known AAA vs no AAA, the incidence of hernias was higher in patients with AAA, compared with patients without AAA [OR: 2.27, 95% CI: 1.66-3.09, I²=84.6%]. Conclusions: Our study findings indicate that a strong association between AWH and AAA exists. AWHs could therefore be used as an additional selection criterion for screening patients for AAA, apart from age, gender, family history and smoking.

Treatment with Hyaluronic Acid and Collagen-Polyvinylpyrrolidone Improves Extracellular Matrix Assembly for Scarring after Tracheal Resection

Treatment of tracheal stenosis is occasionally performed in combination with wound healing modulators to manipulate new extracellular matrix (ECM) formation and prevent fibrosis. Hyaluronic acid (HA) and collagen-polyvinylpyrrolidone (collagen-PVP) decrease fibrosis in experimental tracheal healing. However, they have not been used clinically as their effect on ECM components, which modify tracheal scarring, has not been described. Objective. To evaluate the effect of the application of HA, collagen-PVP, a mixture of HA and collagen-PVP (HA+collagen-PVP), and mitomycin C on the expression of decorin, matrix metalloproteinase 1 (MMP1), and MMP9, as well as the type of collagen and deposits formed in the scar after resection and end-to-end anastomosis (REEA) of the cervical trachea using an experimental model. Materials and Methods. Thirty dogs underwent REEA of the cervical trachea and were treated with different wound healing modulators: group I (n = 6), control; group II (n = 6), HA; group III (n = 6), collagen-PVP; group IV (n = 6), HA+collagen-PVP; and group V (n = 6), mitomycin C. The dogs were evaluated clinically and endoscopically for 4 weeks. Subsequently, macroscopic and microscopic changes, expression of ECM proteins, and collagen deposition in tracheal scars were analysed. Results. Groups II, III, and IV showed reduced endoscopic, macroscopic, and microscopic inflammation, improved neovascularization, high decorin expression (p < 0.01, analysis of variance (ANOVA)), and moderate expression of MMP1 (p < 0.003, ANOVA) and type I and III collagen (p < 0.05, Kruskal–Wallis). Groups IV and V developed fewer collagen deposits (p < 0.001, ANOVA). Conclusion. Treatment with HA and collagen-PVP improved post-REEA healing by increasing neovascularization, stimulating the expression of decorin, and regulating the expression of MMP1, as well as type I and III collagen and their deposition.

Development of calcium phosphate/calcium sulfate biphasic biomedical material with hyaluronic acid containing collagenase and simvastatin for vital pulp therapy

OBJECTIVE

In vital pulp therapy (VPT), a barrier is created with appropriate capping to protect the remaining pulp and thus maintain pulp vitality. Here, we evaluated the feasibility of a biphasic calcium phosphate cement (CPC)-calcium sulfate hemihydrate (CSH) biomaterial containing simvastatin (Sim) and collagenase (Col) for VPT.

METHODS

Combinations of varying CPC and CSH concentrations were analyzed for their handling properties and setting times, with their structures observed through scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS). Drug release patterns of simvastatin and collagenase combined with CPC-CSH (CPC-CSH-Sim-Col) were also analyzed, followed by biocompatibility and bioactivity tests on human dental pulp stem cells (hDPSCs) and in vivo animal study in canine models; the in vivo results were obtained through microcomputed tomography and histological analysis.

RESULTS

The results revealed that 70 wt% CPC (CPC7) with 30 wt% CSH (CSH3) exhibited optimal setting time and porous structure for clinical use. The cell viability and cytotoxicity analysis demonstrated that CPC7-CSH3 with or without simvastatin or collagenase did not injure hDPSCs. In vivo, the CPC7-CSH3-Sim-Col induced dentin bridge formation.

SIGNIFICANCE

CPC7-CSH3-Sim-Col in this study has great potential as a VPT biomaterial to enhance the dentin bridge formation.

Influence of silver-ion-containing pharmacotherapeutic system for repair of anterior abdominal wall on connective tissue formation in experiment

Introduction: In modern medicine new pharmacotherapeutic systems significantly reducing the risk of complications are being actively searched for. The study undertaken was aimed at studying one of such systems consisting of a prosthesis coated with silver ions.

Materials and methods: The material for the study was standard endoprostheses produced by Lintex LLC (St.-Petersburg) for plastic repair of the anterior abdominal wall: Esfil and Uniflex, as well as Plasmofilter produced by Plasmofilter JSC (St.-Petersburg) and a pharmacotherapeutic system containing silver ions (FCS) applied to the experimental samples of endoprostheses – Esfil Ag and Unifleks Ag (patent RU 2473369C1), which were implanted into male Wistar rats. The results were evaluated using morphological, morphometric, immunohistochemical, ionometric, microbiological and statistical methods.

Results and discussion: As a result, it was found that the use of the FCS leads to a more rapid change in inflammation phases. The formation of a mature connective tissue capsule with a thickness of 4.5±0.01 mm was observed by Day 30. The study of the cellular component of the periprosthetic tissue revealed the prevalence of resident cells. The proliferative activity of fibroblastic cells when using FCS over 14 days was statistically significantly (p≤0.05) 3.5-time higher. Microbiological studies confirmed the antibacterial properties of FCS in vivo and in vitro.

Conclusion: The use of FCS contributes to the acceleration of reparative processes, earlier resolution of inflammation and stimulation of collagenesis both under sterile conditions and under microbial conditions.

Umbilical Hernia Repair and Pregnancy: Before, during, after…

Umbilical hernias are most common in women than men. Pregnancy may cause herniation or render a preexisting one apparent, because of progressively raised intra-abdominal pressure. The incidence of umbilical hernia among pregnancies is 0.08%. Surgical algorithm for a pregnant woman with a hernia is not thoroughly clear. There is no consensus about the timing of surgery for an umbilical hernia in a woman either who is already pregnant or planning a pregnancy. If the hernia is incarcerated or strangulated at the time of diagnosis, an emergency repair is inevitable. If the hernia is not complicated, but symptomatic an elective repair should be proposed. When the patient has a small and asymptomatic hernia it may be better to postpone the repair until she gives birth. If the hernia is repaired by suture alone, a high risk of recurrence exists during pregnancy. Umbilical hernia repair during pregnancy can be performed with minimal morbidity to the mother and baby. Second trimester is a proper timing for surgery. Asymptomatic hernias can be repaired, following childbirth or at the time of cesarean section (C-section). Elective repair after childbirth is possible as early as postpartum of eighth week. A 1-year interval can give the patient a very smooth convalescence, including hormonal stabilization and return to normal body weight. Moreover, surgery can be postponed for a longer time even after another pregnancy, if the patients would like to have more children. Diastasis recti are very frequent in pregnancy. It may persist in postpartum period. A high recurrence risk is expected in patients with rectus diastasis. This risk is especially high after suture repairs. Mesh repairs should be considered in this situation.

Mesh materials and hernia repair

Hernia incidence has been observed since ancient time. Advancement in the medical textile industry came up with the variety of mesh materials to repair hernia, but none of them are without complications including recurrence of hernia. Therefore individuals once developed with the hernia could not lead a healthy and comfortable life. This drawn attention of surgeons, patients, researchers and industry to know the exact mechanism behind its development, complications and recurrence. Recent investigations highlighted the role of genetic factors and connective tissue disorders being the reason for the development of hernia apart from the abnormal pressure that is known to develop during other disease conditions. This review discusses different mesh materials, their advantages and disadvantages and their biological response after its implantation.

[Collagen types ratio in prediction of postoperative ventral hernias]

AIM

To analyze collagen types ratio in skin and aponeurosis in order to predict postoperative ventral hernias.

MATERIAL AND METHODS

The trial included 141 patients for the period 2012-2015. Group I (n=65) of patients without ventral hernias was divided into subgroup AI (primary operation, n=41) and BI (re-operation, n=24). Group II consisted of 76 patients with ventral hernias. We performed histological examination of skin and aponeurosis to define the collagen structure of connective tissue.

RESULTS

There were significant differences between collagen type I/III ratio in skin (2.81±0.52 in group I vs. 1.13±0.48 in group II) and aponeurosis (2.69±0.41 vs. 1.09±0.21, respectively, p≤0.05). We revealed strong direct correlation (r=+0.92) between aponeurosis and skin specimens in one group. Collagen type I level was 73.81±2.74% in subgroup AI and 72.03±2.47% in subgroup BI. Collagen type I was predominant (p≤0.05).

CONCLUSION

In patients with ventral hernias collagen type I/III ratio in skin is 2.54 times lower than in patients without hernias. Significant correlation of collagen types in skin and aponeurosis (r= +0.92) allows to predict the risk of postoperative ventral hernias on basis of skin fragment.

Identification of an Electrostatic Ruler Motif for Sequence-Specific Binding of Collagenase to Collagen

Sequence-specific cleavage of collagen by mammalian collagenase plays a pivotal role in cell function. Collagenases are matrix metalloproteinases that cleave the peptide bond at a specific position on fibrillar collagen. The collagenase Hemopexin-like (HPX) domain has been proposed to be responsible for substrate recognition, but the mechanism by which collagenases identify the cleavage site on fibrillar collagen is not clearly understood. In this study, Brownian dynamics simulations coupled with atomic-detail and coarse-grained molecular dynamics simulations were performed to dock matrix metalloproteinase-1 (MMP-1) on a collagen IIIα1 triple helical peptide. We find that the HPX domain recognizes the collagen triple helix at a conserved R-X11-R motif C-terminal to the cleavage site to which the HPX domain of collagen is guided electrostatically. The binding of the HPX domain between the two arginine residues is energetically stabilized by hydrophobic contacts with collagen. From the simulations and analysis of the sequences and structural flexibility of collagen and collagenase, a mechanistic scheme by which MMP-1 can recognize and bind collagen for proteolysis is proposed.

Critical analysis of experimental model for study of adhesions after incisional hernias induced in rats' and repair of abdominal wall with different biomaterials

BACKGROUND

Adhesions induced by biomaterials experimentally implanted in the abdominal cavity are basically studied by primary repair of different abdominal wall defects or by the correction of incisional hernias previously performed with no precise definition of the most appropriate model.

AIM

To describe the adhesions which occur after the development of incisional hernias, before the prosthesis implantation, in an experimental model to study the changes induced by different meshes.

METHODS

Incisional hernias were performed in 10 rats with hernia orifices of standardized dimensions, obtained by the median incision of the abdominal wall and eversion of the defect edges. Ten days after the procedure adhesions of abdominal structures were found when hernias were repaired with different meshes.

RESULTS

The results showed hernia sac well defined in all rats ten days after the initial procedure. Adhesions of the greater omentum occurred in five animals of which two also showed adhesions of small bowel loops besides the omentum, and another two showed liver adhesions as well as the greater omentum, numbers with statistical significance by Student's t test (p<0.05).

CONCLUSION

Although it reproduces the real clinical situation, the choice of experimental model of incisional hernia repair previously induced implies important adhesions, with possible repercussions in the evaluation of the second operation, when different implants of synthetic materials are used.

Laparoscopic ventral hernia repair: outcomes in primary versus incisional hernias: no effect of defect closure

PURPOSE

Supposing divergent aetiology, we found it interesting to investigate outcomes between primary (PH) versus incisional (IH) hernias. In addition, we wanted to analyse the effect of defect closure and mesh fixation techniques.

METHODS

37 patients with PH and 70 with IH were enrolled in a prospective cohort-study, treated with laparoscopic ventral hernia repair (LVHR) and randomised to ± transfascial sutures. In addition, we analysed results from a retrospective study with 36 PH and 51 IH patients. Mean follow-up time was 38 months in the prospective study and 27 months in the retrospective study.

RESULTS

35 % of PH's and 10 % of IH's were recurrences after previous suture repair. No late infections or mesh removals occurred. Recurrence rates in the prospective study were 0 vs. 4.3 % (p = 0.55) and the complication rates were 16 vs. 27 % (p = 0.24) in favour of the PH cohort. The IH group had a mesh protrusion rate of 13 vs. 5 % in the PH group (p = 0.32), and significantly (p < 0.01) larger hernias and adhesion score, longer operating time (100 vs. 79 min) and admission time (2.8 vs. 1.6 days). Closure of the hernia defect did not influence rate of seroma, pain at 2 months, protrusion or recurrence. An overall increased complication rate was seen after defect closure (OR 3.42; CI 1.25-9.33).

CONCLUSIONS

With PH, in comparison to IH treated with LVHR, no differences were observed regarding recurrence, protrusion or complication rates. Defect closure (raphe), when using absorbable suture, did not benefit long-term outcomes and caused a higher overall complication rate. (ClinicalTrials.gov number: NCT00455299).

Volume calculation of rats' organs and its application in the validation of the volume relation between the abdominal cavity and the hernial sac in incisional hernias with "loss of abdominal domain"

BACKGROUND

The calculation of the volume ratio between the hernia sac and the abdominal cavity of incisional hernias is based on tomographic sections as well as the mathematical formula of the volume of the ellipsoid, which allows determining whether this is a giant hernia or there is a "loss of domain". As the images used are not exact geometric figures, the study of the volume of two solid organs of Wistar rats was performed to validate these calculations.

AIM

To correlate two methods for determining the volume of the kidney and spleen of rats, comparing a direct method of observation of the volume with the mathematical calculation of this value.

METHODS

The volume of left kidney, geometrically more regular, and spleen, with its peculiar shape, of ten animals was established in cubic centimeters after complete immersion in water with the aid of a beaker graduated in millimeters. These values ​​were compared with those obtained by calculating the same volume with a specific mathematical formula: V = 4/3 × π × (r1 x r2 x r3). Data were compared and statistically analyzed by Student's t test.

RESULTS

Although the average volume obtained was higher through the direct method (1.13 cm3 for the left kidney and 0.71 cm3 for the spleen) than the values ​​calculated with the mathematical formula (0.81 cm3 and 0.54 cm3), there were no statistically significant differences between the values ​​found for the two organs (p>0.05).

CONCLUSION

There was adequate correlation between the direct calculation of the volume of the kidney and spleen with the result of mathematical calculation of these values ​​in the animals' studies.

Collagen fibers in the rectus abdominis muscle of cadavers of different age

PURPOSE

To assess collagen content and types in the rectus abdominis muscle of cadavers of different ages.

METHODS

Forty fresh adult male cadavers within 24 h of death were obtained from an Institute of Legal Medicine and divided by age at death into Group 1 (mean age, 23.3 years; range, 18-30 years; n = 20) and Group 2 (mean age, 46.2 years; range, 31-60 years; n = 20). From each cadaver, samples of the rectus abdominis muscle measuring 1 cm(2) were collected 3 cm superiorly and 2 cm inferiorly to the umbilicus. Histological sections were prepared and stained with picrosirius red and Masson's trichrome stain for visualization of total collagen fibers, and immunohistochemical analysis was performed to distinguish types I, II, III, IV and V collagen.

RESULTS

No significant differences in total collagen were found between groups by Masson's trichrome staining. However, picrosirius red staining revealed a significantly greater amount and higher concentration of total collagen and types I and III collagen in Group 1 than in Group 2 (P < 0.05). All but type II collagen were detected by immunohistochemistry in both groups. No significant difference in type IV collagen was found between groups. Type V collagen was detected by immunohistochemistry in both groups, but quantification was not possible due to background staining.

CONCLUSION

The amounts of types I and III collagen in the rectus abdominis muscle were significantly smaller in older subjects.

Non-invasive characterization of polyurethane-based tissue constructs in a rat abdominal repair model using high frequency ultrasound elasticity imaging

The evaluation of candidate materials and designs for soft tissue scaffolds would benefit from the ability to monitor the mechanical remodeling of the implant site without the need for periodic animal sacrifice and explant analysis. Toward this end, the ability of non-invasive ultrasound elasticity imaging (UEI) to assess temporal mechanical property changes in three different types of porous, biodegradable polyurethane scaffolds was evaluated in a rat abdominal wall repair model. The polymers utilized were salt-leached scaffolds of poly(carbonate urethane) urea, poly(ester urethane) urea and poly(ether ester urethane) urea at 85% porosity. A total of 60 scaffolds (20 each type) were implanted in a full thickness muscle wall replacement in the abdomens of 30 rats. The constructs were ultrasonically scanned every 2 weeks and harvested at weeks 4, 8 and 12 for compression testing or histological analysis. UEI demonstrated different temporal stiffness trends among the different scaffold types, while the stiffness of the surrounding native tissue remained unchanged. The changes in average normalized strains developed in the constructs from UEI compared well with the changes of mean compliance from compression tests and histology. The average normalized strains and the compliance for the same sample exhibited a strong linear relationship. The ability of UEI to identify herniation and to characterize the distribution of local tissue in-growth with high resolution was also investigated. In summary, the reported data indicate that UEI may allow tissue engineers to sequentially evaluate the progress of tissue construct mechanical behavior in vivo and in some cases may reduce the need for interim time point animal sacrifice.

Lead identification and optimization of novel collagenase inhibitors; pharmacophore and structure based studies

In this study, chemical feature based pharmacophore models of MMP-1, MMP-8 and MMP-13 inhibitors have been developed with the aid of HypoGen module within Catalyst program package. In MMP-1 and MMP-13, all the compounds in the training set mapped HBA and RA, while in MMP-8, the training set mapped HBA and HY. These features revealed responsibility for the high molecular bioactivity, and this is further used as a three dimensional query to screen the knowledge based designed molecules. These pharmacophore models for collagenases picked up some potent and novel inhibitors. Subsequently, docking studies were performed for the potent molecules and novel hits were suggested for further studies based on the docking score and active site interactions in MMP-1, MMP-8 and MMP-13.

Connective tissue alteration in abdominal wall hernia

BACKGROUND

The aetiology and pathogenesis of abdominal wall hernia formation is complex. Optimal treatment of hernias depends on a full understanding of the pathophysiological mechanisms involved in their formation. The aim of this study was to review the literature on specific collagen alterations in abdominal wall hernia formation.

METHODS

A computer-assisted search of the medical databases PubMed and Embase was performed, together with a cross-reference search of eligible papers.

RESULTS

Fifty-two papers were included. Collagen alteration depended on the type of hernia; there were more pronounced changes in patients with a direct inguinal hernia than in those with an indirect inguinal hernia, recurrent inguinal hernia or incisional hernia. A consistent finding was a significant increase in immature type III collagen relative to the stronger type I collagen in patients with a hernia. This resulted in thinner collagen fibres with a correspondingly diminished biomechanical strength. It has been suggested that these alterations are due to variation in the synthesis, maturation or degradation of collagen by matrix metalloproteinases, in combination or alone.

CONCLUSION

Hernia formation and recurrence is associated with altered collagen metabolism manifested by a decreased type I:III collagen ratio.

Differential regulation of MMP-2 in the gastrohepatic ligament of the gastroesophageal junction

INTRODUCTION

Ligamentous attachments maintain the normal anatomic position of the gastroesophageal (GE) junction. Failure of these elastic ligaments through an alteration in collagen synthesis, deposition, and metabolism may be a primary etiology of hiatal hernia formation. Differential expression of zinc-dependent matrix metalloproteinases (MMPs) is largely responsible for collagen remodeling. The purpose of this study was to survey baseline levels of MMPs in supporting ligaments of the GE junction from patients without hiatal hernia.

METHODS

Following an institutional review board-approved protocol, plasma and tissue biopsies of the gastrohepatic ligament (GHL), gastrophrenic ligament (GPL), and phrenoesophageal ligament (PEL) were obtained in six patients without a hiatal hernia during laparoscopic anterior esophageal myotomy for achalasia. Total protein extracts from tissue biopsies were analyzed for elastases MMP-2, -9, and -12 and collagenases MMP-1, -3, -7, -8, and -13 using a multiplex profiling kit (R&D Systems, Minneapolis, MN). Data are reported as mean +/- standard deviation. Statistical significance (p < 0.05) was determined using Tukey's test and analysis of variance.

RESULTS

In control patients without hiatal hernias, increased levels of MMP-2 (p < 0.02) were detected in the GHL compared with the GPL and PEL, respectively. Tissue levels of MMP-1, -12, and -13 were not detectable.

CONCLUSIONS

Gelatinase-A (MMP-2) is present in the GHL and plasma of control patients. The GHL may provide the primary GE junction supporting ligament to compare tissue from patients with type I (sliding) and type III (paraesophageal) hiatal hernias to examine the role of altered collagen metabolism in hiatal hernia formation.

Herniology: past, present, and future

INTRODUCTION

Despite herniorrhaphy being performed frequently, most surgeons consider it to be a minor procedure. However, a few surgeons' views differed.

THE PAST

The Master was Bassini (1884), who introduced a radical cure for inguinal hernia. Incising his triple layer, internal oblique, transversus, and transversalis, he entered the preperitoneal space, allowing high ligation of the sac and mass suturing to the inguinal ligament. A 2.7% recurrence rate evoked worldwide emulation. Corruption ensued. The cremaster remained and few unincised layers were stitched, without imbrications, along with reinforcement using the cremaster or rectus muscles, fascial flaps, relaxing incisions, and silver coils. Little improvement cast doubt on Bassini's work. Russell's (Lancet 2:1197-1203, 1906) ligation of the hernial sac was adopted until 1953, when the Shouldice clinic revived Bassini's tenets, becoming the gold standard for decades. Cheatle (Br Med J 2:68-69, 1920) introduced posterior pre-peritoneal repair. Acquaviva and Bourret (Presse Med 73:892, 1948) designed the first plastic prosthesis (nylon), replaced by polypropylene. Usher (Surg Gynecol Obstet 117:239-240, 1963) parietalized the cord. These contributions paved the way for the Rives, Stoppa, Wantz, and Gilbert repairs, Ger's laparoscopic approach, and less common herniorrhaphies.

THE PRESENT

Chevrel (1979) formed the GREPA, which evolved into the European Hernia Society (EHS), joining with the American Hernia Society (AHS) to form the journal 'Hernia.' Nilsson (1993) instituted national hernia registries, enabling less recurrences and better prospective research.

THE FUTURE

In the 21st century, the Lichtenstein procedure has dominated inguinal herniorrhaphy. Herniologists accepted systemic connective tissue disorder as the etiology of abdominal hernia and pelvic prolapses. This malady explains why prostheses slow but do not eliminate recurrence. Antidotes need to be developed and employed.

CONCLUSION

This malady explains why prostheses slow but do not eliminate recurrence. Antidotes need to be developed and employed.

Herniology: past, present, and future

INTRODUCTION

Despite herniorrhaphy being performed frequently, most surgeons consider it to be a minor procedure. However, a few surgeons' views differed.

THE PAST

The Master was Bassini (1884), who introduced a radical cure for inguinal hernia. Incising his triple layer, internal oblique, transversus, and transversalis, he entered the preperitoneal space, allowing high ligation of the sac and mass suturing to the inguinal ligament. A 2.7% recurrence rate evoked worldwide emulation. Corruption ensued. The cremaster remained and few unincised layers were stitched, without imbrications, along with reinforcement using the cremaster or rectus muscles, fascial flaps, relaxing incisions, and silver coils. Little improvement cast doubt on Bassini's work. Russell's (Lancet 2:1197-1203, 1906) ligation of the hernial sac was adopted until 1953, when the Shouldice clinic revived Bassini's tenets, becoming the gold standard for decades. Cheatle (Br Med J 2:68-69, 1920) introduced posterior pre-peritoneal repair. Acquaviva and Bourret (Presse Med 73:892, 1948) designed the first plastic prosthesis (nylon), replaced by polypropylene. Usher (Surg Gynecol Obstet 117:239-240, 1963) parietalized the cord. These contributions paved the way for the Rives, Stoppa, Wantz, and Gilbert repairs, Ger's laparoscopic approach, and less common herniorrhaphies.

THE PRESENT

Chevrel (1979) formed the GREPA, which evolved into the European Hernia Society (EHS), joining with the American Hernia Society (AHS) to form the journal 'Hernia.' Nilsson (1993) instituted national hernia registries, enabling less recurrences and better prospective research.

THE FUTURE

In the 21st century, the Lichtenstein procedure has dominated inguinal herniorrhaphy. Herniologists accepted systemic connective tissue disorder as the etiology of abdominal hernia and pelvic prolapses. This malady explains why prostheses slow but do not eliminate recurrence. Antidotes need to be developed and employed.

CONCLUSION

This malady explains why prostheses slow but do not eliminate recurrence. Antidotes need to be developed and employed.

Mesh repair of common abdominal hernias: a review on experimental and clinical studies

Results on hernia surgery from numerous centers confirm that tensionless repair with various meshes reduces the complication rates and the frequency of recurrences. Some evidence on incisional hernias suggests, however, that the use of mesh seems to transfer the onset of recurrences by several years. Persistent pain and other discomfort is also an unpleasant complication of otherwise successful surgery in a number of patients. Thus, improved, slowly degrading, mesh materials, with strong connective tissue-inducing action, might be more optimal for hernia surgery. Accumulating evidence also suggests that recurrent hernias appear in patients having inherited weakness of connective tissues. Numerous tissue specific collagens, in addition to the classical fibrillar I-III collagens and numerous substrate specific matrix proteinases, have recently been described in biochemical literature, and their roles as possible causes of tissue weakness are discussed.