Innovative approaches for induction of gastrointestinal anastomotic healing: an update on experimental and clinical aspects

The Effect of Albumin/Glutaraldehyde Glue (Bioglue) on Colonic Anastomosis Under Intestinal Obstruction: An Experimental Study in Rats

Background/Objectives: Healing of colonic anastomoses is critical to surgical recovery, particularly under obstructive ileus conditions. Adhesive biological materials such as albumin/glutaraldehyde glue (Bioglue) show potential in enhancing anastomotic healing and minimizing complications. This study investigates the effect of Bioglue on colonic anastomoses healing under obstructive ileus conditions in rats. Methods: Eighty albino Wistar rats were divided into control, ileus, Bioglue, and ileus + Bioglue groups (n = 20 each). Subgroups (n = 10) were sacrificed on the 4th or 8th postoperative day. In the control and Bioglue groups, end-to-end anastomoses were performed after colonic resection. In the ileus and ileus + Bioglue groups, obstructive ileus was induced by colonic ligation, followed by resection and primary anastomosis. Bioglue was applied in the Bioglue and ileus + Bioglue groups. Assessments included bursting pressure, peritoneal adhesion and inflammation scores, and biochemical markers (fibroblast activity, neoangiogenesis, collagen deposition, hydroxyproline, and collagenase concentrations). Results: Bursting pressure and fibroblast activity were significantly higher in the ileus + Bioglue group compared to the ileus group on both postoperative days. Although anastomotic rupture occurred in the ileus and ileus + Bioglue groups, the incidence was not significantly different from the control and Bioglue groups. Ileus + Bioglue showed significantly higher adhesion scores, inflammatory infiltration, neoangiogenesis, and collagen deposition compared to the control and ileus groups. Hydroxyproline was significantly elevated in the ileus + Bioglue group on the 8th day. Collagenase I concentrations were higher in ileus + Bioglue but not significant. Conclusions: Bioglue application enhances colonic anastomotic healing under obstructive ileus conditions, improving mechanical strength and promoting tissue repair by the 4th and 8th postoperative days. These findings support its potential clinical application.

Usefulness of intraoperative colonoscopy and synchronous scoring system for determining the integrity of the anastomosis in left-sided colectomy: a single-center retrospective cohort study

OBJECTIVES

The aim of this study is to evaluate the utilization of intraoperative colonoscopy (IOC) for determining the integrity of the anastomosis and to establish an IOC scoring system.

METHODS

A retrospective cohort study was conducted from January 2021 to June 2024, we analyzed the clinical data of 160 patients registered in a database who underwent laparoscopic left-sided colectomy at Pusan National University Yangsan Hospital. IOC was performed on all patients, and Mucosal color (MC), stapled line bleeding (BL), proximal redundancy (PR), and bowel preparation (BP) were evaluated and scored as variables. Logistic regression analysis was used to evaluate risk factors for anastomotic leakage (AL) and Cohen's kappa was applied to assess the reproducibility of the evaluation.

RESULTS

Of 160 patients, 10 (6.25%) experienced AL. All the IOC variables had kappa values of 0.8 or higher, indicating good agreement. The logistic regression analysis revealed significant differences in the MC 2 (P = 0.017, OR 12.86), PR 2 (P = 0.001, OR 27.64), BP 2 (p = 0.016, OR 10.50) PR 2 score (P = 0.016, OR 10.50) and the sum of the scores (p = 0.001, OR 3.51).

CONCLUSION

IOC can be performed as a reference procedure to assess the integrity of the anastomosis during left-sided colorectal surgery.

Non-Thermal Atmospheric Pressure Plasma as an Adjunct to Intestinal Anastomosis: A Pilot Study on Preventing Anastomotic Leaks

Anastomotic leaks remain a significant challenge in intestinal surgery, often leading to severe complications. This study investigated a novel approach to enhance anastomotic healing and reduce the risk of leaks by combining traditional suturing and stapling techniques with non-thermal atmospheric pressure plasma (NTAPP) application. NTAPP, a cold atmospheric plasma generated through the ionization of ambient air, has been shown to possess antimicrobial, hemostatic, and wound-healing properties. NTAPP promotes sterilization, coagulation, and tissue regeneration by generating reactive oxygen and nitrogen species, potentially strengthening anastomotic union. This pilot study evaluated the efficacy of NTAPP in three patients undergoing intestinal anastomosis. Following the standard surgical procedure, NTAPP was applied directly to the anastomotic site. Postoperative outcomes were monitored for six months, including anastomotic leaks and healing rates. Preliminary results demonstrated promising outcomes. All three patients exhibited successful sealing of the anastomosis, with no evidence of leakage during the follow-up period, providing reassurance and confidence in the potential of sutures, staples, and NTAPP. These findings suggest that NTAPP can significantly improve the safety and efficacy of intestinal surgeries by reducing the incidence of anastomotic leaks. While further research with a larger sample is necessary to confirm these initial findings, the results of this study provide a strong foundation for exploring the potential of NTAPP as a valuable adjunct to conventional surgical techniques for preventing anastomotic leaks. This innovative approach could reduce postoperative complications, improve patient outcomes, and enhance the overall quality of care in intestinal surgery.

Alpha-1-antitrypsin improves anastomotic healing in intestinal epithelial cells model

PURPOSE

Intestinal anastomosis is a routine procedure in pediatric surgery, with leakage being a significant complication. Human alpha1-antitrypsin (AAT), whose physiological serum concentrations range from 0.9-2.0 mg/ml, is known to accelerate wound healing and stimulate the expression of cell proliferation-related genes. We hypothesized that AAT might enhance anastomotic healing.

METHODS

In a monolayer of non-tumorigenic HIEC-6 epithelial cells derived from fetal intestine a scratch was created. Standard medium without (control) or with AAT (0.5 and 1 mg/ml) was added. Cells were observed using a Life-Cell Imaging System. Cell proliferation was assessed, and the expression of proliferation-related genes was measured by qRT-PCR.

RESULTS

In the presence of AAT, the scratch closed significantly faster. Cells treated with 1 mg/ml AAT showed 53% repopulation after 8 h and 97% after 18 h, while control cells showed 24% and 60% repopulation, respectively (p < 0.02). The treatment with AAT induced HIEC-6-cell proliferation and significantly increased the mRNA-expression of CDKN1A, CDKN2A, ANGPTL4, WNT3 and COL3A1 genes. AAT did not change the mRNA-expression of CXCL8 but decreased levels of IL-8 as compared to controls.

CONCLUSION

At physiological concentrations AAT accelerates the confluence of intestinal cells and increases cell proliferation. The local administration of AAT may bear therapeutic potential to improve anastomotic healing.

Magnamosis improves the healing of gastrojejunal anastomosis and down-regulates TGF-β1 and HIF-1α in rats

This study elucidated the unique pathological features of tissue healing by magnamosis and revealed the changes in landmark molecule expression levels related to collagen synthesis and tissue hypoxia. Forty-eight male Sprague-Dawley rats were divided into the magnamosis and suture anastomosis groups, and gastrojejunal anastomosis surgery was performed. Rats were dissected at 6, 24, and 48 h and 5, 6, 8, 10, and 12 days postoperatively. Hematoxylin, eosin, and Masson's trichrome staining were used to evaluate granulation tissue proliferation and collagen synthesis density at the anastomosis site. Immunohistochemistry was used to measure TGF-β1 and HIF-1α expression levels. Magnamosis significantly shortened the operation time, resulting in weaker postoperative abdominal adhesions (P < 0.0001). Histopathological results showed a significantly lower granulation area in the magnamosis group than in the suture anastomosis group (P = 0.0388), with no significant difference in the density of collagen synthesis (P = 0.3631). Immunohistochemistry results indicated that the magnamosis group had significantly lower proportions of TGF-β1-positive cells at 24 (P = 0.0052) and 48 h (P = 0.0385) postoperatively and HIF-1α-positive cells at 24 (P = 0.0402) and 48 h postoperatively (P = 0.0005). In a rat model of gastrojejunal anastomosis, magnamosis leads to improved tissue healing at the gastrojejunal anastomosis, associated with downregulated expression levels of TGF-β1 and HIF-1α.

Experimental models of high-risk bowel anastomosis in rats: A systematic review

BACKGROUND

Anastomotic leaks remain one of the most dreaded complications in gastrointestinal surgery causing significant morbidity, that negatively affect the patients' quality of life. Experimental studies play an important role in understanding the pathophysiological background of anastomotic healing and there are still many fields that require further investigation. Knowledge drawn from these studies can lead to interventions or techniques that can reduce the risk of anastomotic leak in patients with high-risk features. Despite the advances in experimental protocols and techniques, designing a high-quality study is still challenging for the investigators as there is a plethora of different models used.

AIM

To review current state of the art for experimental protocols in high-risk anastomosis in rats.

METHODS

This systematic review was performed according to The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. To identify eligible studies, a comprehensive literature search was performed in the electronic databases PubMed (MEDLINE) and Scopus, covering the period from conception until 18 October 2023.

RESULTS

From our search strategy 102 studies were included and were categorized based on the mechanism used to create a high-risk anastomosis. Methods of assessing anastomotic healing were extracted and were individually appraised.

CONCLUSION

Anastomotic healing studies have evolved over the last decades, but the findings are yet to be translated into human studies. There is a need for high-quality, well-designed studies that will help to the better understanding of the pathophysiology of anastomotic healing and the effects of various interventions.

Side-to-side magnetic duodeno-ileostomy in adults with severe obesity with or without type 2 diabetes: early outcomes with prior or concurrent sleeve gastrectomy

BACKGROUND

Conventional metabolic/bariatric surgical anastomoses with sutures/staples may cause severe adverse events (AEs).

OBJECTIVES

The study aim was to evaluate the feasibility, safety, and effectiveness of primary and revisional side-to-side duodeno-ileostomy (DI) bipartition using a novel magnetic compression anastomosis device (Magnet Anastomosis System [MS]).

SETTING

Multicenter: private practices and university hospitals.

METHODS

In patients with body mass index ([BMI, kg/m2] ≥35.0 to ≤50.0 with/without type 2 diabetes [T2D] glycosylated hemoglobin [HbA1C > 6.5 %]), two linear MS magnets were delivered endoscopically to the duodenum and ileum with laparoscopic assistance and aligned, initiating magnet fusion and gradual DI (MagDI). The MagDI-after-SG group had undergone prior sleeve gastrectomy (SG); the MagDI + SG group underwent concurrent SG. AEs were graded by Clavien-Dindo Classification (CDC).

RESULTS

Between November 22, 2021 and May 30, 2023, 43 patients (88.0% female, mean age 43.7 ± 1.3 years) underwent the study procedures. The MS met feasibility criteria of magnet device placement, creation of patent anastomoses confirmed radiologically, and magnet passage in 100.0% of patients. There were 64 AEs, most were CDC grade I and II, significantly fewer in the MagDI-after-SG group (P < .001). No device-related AEs including anastomotic leakage, bleeding, obstruction, infection, or death. The MagDI-after-SG group experienced 6-month mean weight loss of 8.0 ± 2.5 kg (P < .01), 17.4 ± 5.0% excess weight loss (EWL). The MagDI + SG group had significantly greater weight loss (34.2 ± 1.6 kg, P < .001), 66.2 ± 3.4% EWL. All patients with T2D improved.

CONCLUSIONS

In early results of a multicenter study, the incisionless, sutureless Magnet System formed patent, complication-free anastomoses in side-to-side DI with prior or concurrent SG.

A novel discrete linkage-type electrode for radiofrequency-induced intestinal anastomosis

INTRODUCTION

For decades, radiofrequency (RF)-induced tissue fusion has garnered great attention due to its potential to replace sutures and staples for anastomosis of tissue reconstruction. However, the complexities of achieving high bonding strength and reducing excessive thermal damage present substantial limitations of existing fusion devices.

MATERIALS AND METHODS

This study proposed a discrete linkage-type electrode to carry out ex vivo RF-induced intestinal anastomosis experiments. The anastomotic strength was examined by burst pressure and shear strength test. The degree of thermal damage was monitored through an infrared thermal imager. And the anastomotic stoma fused by the electrode was further investigated through histopathological and ultrastructural observation.

RESULTS

The burst pressure and shear strength of anastomotic tissue can reach 62.2 ± 3.08 mmHg and 8.73 ± 1.11N, respectively, when the pressure, power and duration are 995 kPa, 160 W and 13 s, and the thermal damage can be controlled within limits. Histopathological and ultrastructural observation indicate that an intact and fully fused stomas with collagenic crosslink can be formed.

CONCLUSION

The discrete linkage-type electrode presents favorable efficiency and security in RF-induced tissue fusion, and these results are informative to the design of electrosurgical medical devices with controllable pressure and energy delivery.

Side-to-side magnet anastomosis system duodeno-ileostomy with sleeve gastrectomy: early multi-center results

INTRODUCTION

Gastrointestinal anastomoses with classical sutures and/or metal staples have resulted in significant bleeding and leak rates. This multi-site study evaluated the feasibility, safety, and preliminary effectiveness of a novel linear magnetic compression anastomosis device, the Magnet System (MS), to form a side-to-side duodeno-ileostomy (DI) diversion for weight loss and type 2 diabetes (T2D) resolution.

METHODS

In patients with class II and III obesity (body mass index [BMI, kg/m2] ≥ 35.0- ≤ 50.0 with/without T2D [HbA1C > 6.5%]), two linear MS magnets were delivered endoscopically to the duodenum and ileum with laparoscopic assistance and aligned, initiating DI; sleeve gastrectomy (SG) was added. There were no bowel incisions or retained sutures/staples. Fused magnets were expelled naturally. Adverse events (AEs) were graded by Clavien-Dindo Classification (CDC).

RESULTS

Between November 22, 2021 and July 18, 2022, 24 patients (83.3% female, mean ± SEM weight 121.9 ± 3.3 kg, BMI 44.4 ± 0.8) in three centers underwent magnetic DI. Magnets were expelled at a median 48.5 days. Respective mean BMI, total weight loss, and excess weight loss at 6 months (n = 24): 32.0 ± 0.8, 28.1 ± 1.0%, and 66.2 ± 3.4%; at 12 months (n = 5), 29.3 ± 1.5, 34.0 ± 1.4%, and 80.2 ± 6.6%. Group mean respective mean HbA1C and glucose levels dropped to 1.1 ± 0.4% and 24.8 ± 6.6 mg/dL (6 months); 2.0 ± 1.1% and 53.8 ± 6.3 mg/dL (12 months). There were 0 device-related AEs, 3 procedure-related serious AEs. No anastomotic bleeding, leakage, stricture, or mortality.

CONCLUSION

In a multi-center study, side-to-side Magnet System duodeno-ileostomy with SG in adults with class III obesity appeared feasible, safe, and effective for weight loss and T2D resolution in the short term.

Mesenchymal stem cell secretome-loaded fibrin glue improves the healing of intestinal anastomosis

Anastomotic leakage is a serious complication following gastrointestinal surgery and one of the leading causes of patient mortality. Despite the significant clinical and economic burden, there are currently no reliable treatment options to improve the healing of intestinal anastomosis and subsequently prevent anastomotic leakage. Recently, the development of regenerative medicine has shown promise for improving anastomotic healing. Recent studies have illustrated that stem cell-derived secretome can enhance tissue regeneration without the safety and ethical limitations of stem cell transplantation. Herein, we developed a fibrin glue topical delivery system loaded with mesenchymal stem cells (MSCs)-derived secretome for controlled delivery of bioactive factors, and evaluated its application potential in improving the healing of intestinal anastomosis. Under in vitro conditions, the MSCs secretome significantly promoted cell proliferation viability in a dose-dependent manner and resulted in the controlled release of growth factors via fibrin glue delivery. We established a rat surgical anastomotic model and experimentally found that MSCs secretome-loaded fibrin glue enhanced anastomotic bursting pressure, increased granulation tissue formation and collagen deposition, and significantly promoted anastomotic healing. Mechanistically, fibrin glue accelerated cell proliferation, angiogenesis, and macrophage M2 polarization at the surgical anastomotic site by releasing bioactive factors in the secretome, and it also alleviated the inflammatory response and cell apoptosis at the anastomotic site. Our results demonstrated for the first time that MSCs-derived secretome could promote the healing of intestinal anastomosis. Considering the accessibility and safety of the cell-free secretome, we believed that secretome-loaded fibrin glue would be a cell-free therapy to accelerate the healing of intestinal anastomosis with great potential for clinical translation.

The Influence of the Microbiome on Anastomotic Leak

Anastomotic leak, defined by the International Study Group of Rectal Cancer as "a communication between the intra- and extraluminal compartments owing to a defect of the integrity of the intestinal wall at the anastomosis," is one of the most devastating complications in colorectal surgery. Much work has been done to identify causes of leak; however, despite advances in surgical technique, the prevalence of anastomotic leak has remained at around 11%. The potential causative role of bacteria in the etiopathology of anastomotic leak was established in the 1950s. More recently, alterations in the colonic microbiome have been shown to affect rates of anastomotic leak. Multiple perioperative factors that alter the homeostasis of the gut microbiota community structure and function have been linked to anastomotic leak after colorectal surgery. Here, we discuss the role of diet, radiation, bowel preparation, medications including nonsteroidal anti-inflammatory drugs, morphine, and antibiotics, and specific microbial pathways that have been implicated in anastomotic leak via their effects on the microbiome.

A nationwide population-based study on the clinical and economic burden of anastomotic leakage in colorectal surgery

AIM

Anastomotic leakage (AL) is one of the most dreaded complications in colorectal surgery. In 2013, the International Classification of Diseases code K91.83 for AL was introduced in Germany, allowing nationwide analysis of AL rates and associated parameters. The aim of this population-based study was to investigate the current incidence, risk factors, mortality, clinical management, and associated costs of AL in colorectal surgery.

METHODS

A data query was performed based on diagnosis-related group data of all hospital cases of inpatients undergoing colon or sphincter-preserving rectal resections between 2013 and 2018 in Germany.

RESULTS

A total number of 690,690 inpatient cases were included in this study. AL rates were 6.7% for colon resections and 9.2% for rectal resections in 2018. Regarding the treatment of AL, the application of endoluminal vacuum therapy increased during the studied period, while rates of relaparotomy, abdominal vacuum therapy, and terminal enterostomy remained stable. AL was associated with significantly increased in-house mortality (7.11% vs. 20.11% for colon resections and 3.52% vs. 11.33% for rectal resections in 2018) and higher socioeconomic costs (mean hospital reimbursement volume per case: 14,877€ (no AL) vs. 37,521€ (AL) for colon resections and 14,602€ (no AL) vs. 30,606€ (AL) for rectal resections in 2018).

CONCLUSIONS

During the studied time period, AL rates did not decrease, and associated mortality remained at a high level. Our study provides updated population-based data on the clinical and economic burden of AL in Germany. Focused research in the field of AL is still urgently necessary to develop targeted strategies to prevent AL, improve patient care, and decrease socioeconomic costs.

Which Suture to Choose in Hepato-Pancreatic-Biliary Surgery? Assessment of the Influence of Pancreatic Juice and Bile on the Resistance of Suturing Materials—In Vitro Research

(1) Background: The choice of appropriate surgical suture during operation is of great significance. Currently, there are no objective studies regarding the resistance of commonly used sutures in biliary tract surgery. (2) Methods: This fact leads one to conduct research concerning the resistance of the sutures (Polydioxanone, Poliglecaprone, Poliglactin 910, and their analogues coated with antibacterial triclosan) in the environment of sterile and contaminated bile and pancreatic juice. Tensile strength was tested at days 0, 7, 14, 21, and 28 of research. The study was performed in in vitro conditions for 28 days. (3) Results: Pancreatic juice and bile has a significant influence on the tensile strength of each suture. (4) Conclusions: The study indicated that sutures made of polydioxanone had the best qualities during the entire experiment.

Stem cell therapy applied for digestive anastomosis: Current state and future perspectives

BACKGROUND

Digestive tract resections are usually followed by an anastomosis. Anastomotic leakage, normally due to failed healing, is the most feared complication in digestive surgery because it is associated with high morbidity and mortality. Despite technical and technological advances and focused research, its rates have remained almost unchanged the last decades. In the last two decades, stem cells (SCs) have been shown to enhance healing in animal and human studies; hence, SCs have emerged since 2008 as an alternative to improve anastomoses outcomes.

AIM

To summarise the published knowledge of SC utilisation as a preventative tool for hollow digestive viscera anastomotic or suture leaks.

METHODS

PubMed, Science Direct, Scopus and Cochrane searches were performed using the key words "anastomosis", "colorectal/colonic anastomoses", "anastomotic leak", "stem cells", "progenitor cells", "cellular therapy" and "cell therapy" in order to identify relevant articles published in English and Spanish during the years of 2000 to 2021. Studies employing SCs, performing digestive anastomoses in hollow viscera or digestive perforation sutures and monitoring healing were finally included. Reference lists from the selected articles were reviewed to identify additional pertinent articles.Given the great variability in the study designs, anastomotic models, interventions (SCs, doses and vehicles) and outcome measures, performing a reliable meta-analysis was considered impossible, so we present the studies, their results and limitations.

RESULTS

Eighteen preclinical studies and three review papers were identified; no clinical studies have been published and there are no registered clinical trials. Experimental studies, mainly in rat and porcine models and occasionally in very adverse conditions such as ischaemia or colitis, have been demonstrated SCs as safe and have shown some encouraging morphological, functional and even clinical results. Mesenchymal SCs are mostly employed, and delivery routes are mainly local injections and cell sheets followed by biosutures (sutures coated by SCs) or purely topical. As potential weaknesses, animal models need to be improved to make them more comparable and equivalent to clinical practice, and the SC isolation processes need to be standardised. There is notable heterogeneity in the studies, making them difficult to compare. Further investigations are needed to establish the indications, the administration system, potential adjuvants, the final efficacy and to confirm safety and exclude definitively oncological concerns.

CONCLUSION

The future role of SC therapy to induce healing processes in digestive anastomoses/sutures still needs to be determined and seems to be currently far from clinical use.

Can physical prehabilitation prevent complications after colorectal cancer surgery in frail older patients?

INTRODUCTION

Frail patients with colorectal cancer (CRC) are at increased risk of complications after surgery. Prehabilitation seems promising to improve this outcome and therefore we evaluated the effect of physical prehabilitation on postoperative complications in a retrospective cohort of frail CRC patients.

METHODS

The study consisted of all consecutive non-metastatic CRC patients ≥70 years who had elective surgery from 2014 to 2019 in a teaching hospital in the Netherlands, where a physical prehabilitation program was implemented from 2014 on. We performed both an intention-to-treat and per protocol analysis to evaluate postoperative complications in the physical prehabilitation (PhP) and non-prehabilitation (NP) group.

RESULTS

Eventually, 334 elective patients were included. The 124 (37.1%) patients in the PhP-group presented with higher age, higher comorbidity scores and walking-aid use compared to the NP-group. Medical complications occurred in 26.6% of the PhP-group and in 20.5% of the NP-group (p = 0.20) and surgical complications in 19.4% and 14.3% (p = 0.22) respectively. In all frailty subgroups, the medical complications were lower in the PhP-group compared to the NP-group (35.9% vs. 45.5% for patients with ≥2 comorbidities, 36.2% vs. 39.1% for ASA score ≥ III, 29.2% vs. 45.8% for walking-aid use). Differences were not significant.

CONCLUSIONS

In this study, patients selected for physical prehabilitation had a worse frailty profile and therefore a higher a priori risk of postoperative complications. However, the postoperative complication rate was not increased compared to patients who were less frail at baseline and without prehabilitation. Hence, physical prehabilitation may prevent postoperative complications in frail CRC patients ≥70 years.

A Human Cellular Model for Colorectal Anastomotic Repair: The Effect of Localization and Transforming Growth Factor-β1 Treatment on Collagen Deposition and Biomarkers

Anastomotic leakage (AL) is a devastating complication after colorectal surgery, possibly due to the loss of stabilizing collagen fibers in the submucosa. Our aim was to assess the formation of collagen in the colon versus the rectum with or without transforming growth factor (TGF)-β1 exposure in a human cellular model of colorectal repair. Primary fibroblasts were isolated by an explant procedure from clinically resected tissue rings during anastomosis construction in 19 consecutive colorectal patients who underwent laparoscopy. The cells, identified as fibroblasts by morphologic characteristics and flow cytometry analysis (CD90⁺), were cultured for 8 days and in 12 patients in the presence of 1 ng/mL TGF-β1. Total collagen deposition was measured colorimetrically after Sirius red staining of fixed cell layers, and type I, III, and VI collagen biosynthesis and degradation were specifically determined by the biomarkers PINP, PRO-C3, PRO-C6, and C3M in conditioned media by competitive enzyme-linked immunosorbent assays. Total collagen deposition by fibroblasts from the colon and rectum did not significantly differ. TGF-β1 treatment increased PINP, PRO-C6, and total collagen deposition. Mechanistically, TGF-β1 treatment increased COL1A1 and ACTA2 (encoding α-smooth muscle actin), and decreased COL6A1 and MMP2 mRNA levels in colorectal fibroblasts. In conclusion, we found no effect of anatomic localization on collagen production by fibroblasts derived from the large intestine. TGF-β1 represents a potential therapeutic agent for the prevention of AL by increasing type I collagen synthesis and collagen deposition.