Effects of melatonin on colonic anastomosis healing following chemotherapy in rats

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.

Can supplementation of tryptophan in parenteral nutrition increase melatonin and alleviate inflammatory response?

OBJECTIVE

Endogenous melatonin is produced from tryptophan which is an essential amino acid. Besides its role in the regulation of sleep patterns, melatonin has anti-inflammatory effects. In this case-control study, we aimed to compare tryptophan and melatonin levels and their relationship with the inflammatory response, specifically serum interleukin-1, interleukin-6, and c-reactive protein levels following major abdominal surgery in patients with food restriction and who receive parenteral nutritional therapy.

METHODS

We enrolled 40 patients between the ages of 18 and 65 years in the study. We collected blood and urine samples 48 h before the operation and on postoperative days 1, 3, and 5.

RESULTS AND CONCLUSION

The tryptophan levels in the experimental group were higher than in the control group but failed to reach any statistical difference. Melatonin levels were increased in both groups following the surgery compared with preoperative levels. The increase in the experimental group was statistically different 3 days after the surgery. The difference in the level of interleukin-1 between the control and the experimental groups was greatest on postoperative day 3. On postoperative day 3, the interleukin-6 level in the treatment group was slightly higher than in the control group. We did not find any difference in the levels of c-reactive protein between the groups. As a result, the levels of tryptophan and melatonin were increased in the parenteral nutrition group, irrespective of the postoperative inflammatory response.

Protective and therapeutic potential of melatonin against intestinal diseases: updated review of current data based on molecular mechanisms

INTRODUCTION

Intestinal diseases, a leading global cause of mortality and morbidity, carry a substantial socioeconomic burden. Small and large intestines play pivotal roles in gastrointestinal physiology and food digestion. Pathological conditions, such as gut dysbiosis, inflammation, cancer, therapy-related complications, ulcers, and ischemia, necessitate the urgent exploration of safe and effective complementary therapeutic strategies for optimal intestinal health.

AREAS COVERED

This article evaluates the potential therapeutic effects of melatonin, a molecule with a wide range of physiological actions, on intestinal diseases including inflammatory bowel disease, irritable bowel syndrome, colon cancer, gastric/duodenal ulcers and other intestinal disorders.

EXPERT OPINION

Due to anti-inflammatory and antioxidant properties as well as various biological actions, melatonin could be a therapeutic option for improving digestive disorders. However, more researches are needed to fully understand the potential benefits and risks of using melatonin for digestive disorders.

Melatonin and 5-fluorouracil combination chemotherapy: opportunities and efficacy in cancer therapy

Combined chemotherapy is a treatment method based on the simultaneous use of two or more therapeutic agents; it is frequently necessary to produce a more effective treatment for cancer patients. Such combined treatments often improve the outcomes over that of the monotherapy approach, as the drugs synergistically target critical cell signaling pathways or work independently at different oncostatic sites. A better prognosis has been reported in patients treated with combination therapy than in patients treated with single drug chemotherapy. In recent decades, 5-fluorouracil (5-FU) has become one of the most widely used chemotherapy agents in cancer treatment. This medication, which is soluble in water, is used as the first line of anti-neoplastic agent in the treatment of several cancer types including breast, head and neck, stomach and colon cancer. Within the last three decades, many studies have investigated melatonin as an anti-cancer agent; this molecule exhibits various functions in controlling the behavior of cancer cells, such as inhibiting cell growth, inducing apoptosis, and inhibiting invasion. The aim of this review is to comprehensively evaluate the role of melatonin as a complementary agent with 5-FU-based chemotherapy for cancers. Additionally, we identify the potential common signaling pathways by which melatonin and 5-FU interact to enhance the efficacy of the combined therapy. Video abstract.

Protective Effects of Alpha-Lipoic Acid against 5-Fluorouracil-Induced Gastrointestinal Mucositis in Rats

Alpha-lipoic acid (ALA) is extensively utilized in multivitamin formulas and anti-aging products. The purpose of this study was to investigate the potential protective benefits of ALA on 5-fluorouracil (5-FU)-induced gastrointestinal mucositis in Wistar albino rats. Tissues from the stomach, small intestine, and large intestine were excised, and blood sera were obtained to identify biochemical indices such as TNF-α, IL-1β, MDA, GPx, SOD, MMP-1, -2, -8, and TIMP-1. A histopathological study was also performed. The results revealed mucositis-elevated TNF-, IL-1, MDA, MMP-1, -2, -8, and TIMP-1 levels in both tissues and sera, and these values dropped dramatically following ALA treatment. Reduced SOD and GPx activities in mucositis groups were reversed in ALA-treated groups. The damage produced by mucositis in the stomach and small intestine regressed in the ALA-treated group, according to histopathological evaluation. Consequently, the implementation of ALA supplementation in 5-FU therapy may act as a protective intervention for cancer patients with gastrointestinal mucositis. In light of the findings, ALA, a food-derived antioxidant with pleiotropic properties, may be an effective treatment for 5-FU-induced gastrointestinal mucositus, and prevent oxidative stress, inflammation, and tissue damage in cancer patients receiving 5-FU therapy.

Arterial supply to the rat colon

Rats are often used as animal models in studies such as on intestinal transplantation and anastomosis healing, which require colectomy. Although detailed information regarding arterial supply is important to establish accurate and reproducible experimental procedures, this has not been studied in the rat colon. Therefore, we analysed the detailed arterial distribution pattern and its individual variations in the colon of 34 rats. The rat colon received colic branches of the ileocolic artery, and the right, middle and left colic arteries. The single left colic artery constantly arose from the caudal mesenteric artery and was distributed to the descending colon, whereas the others showed variations in number and distribution. The ileocolic artery gave rise to one (12%) or two (88%) colic branches supplying the proximal ascending colon, and these branches formed rich, mesh-like anastomoses along the initial portion of the ascending colon. One (74%) or two (26%) right colic arteries originated from the cranial mesenteric artery and supplied the ascending colon and right colic flexure. Moreover, one (38%), two (56%) or three (6%) middle colic arteries emerged from the cranial mesenteric artery and were distributed to the transverse colon, left colic flexure and proximal descending colon. In total, we categorized the individual variations in arterial branching and anastomosis into 11 patterns. Arterial supply to the rat colon showed a specific pattern and frequent individual variations. These findings thus provide essential information for establishing reproducible models of rat colic surgery.

Comparison of the efficacy of growth factor collagen and antibiotic collagen on colon anastomosis in experimental animals with peritonitis

INTRODUCTION

In spite of advances in surgical techniques, the significance of anastomosis leak continues in colorectal surgery. There is no ideal method in spite of all studies and technical advances in this field. Our aim of this study was to use fibroblast growth factor collagen (FGF-C) and antibiotic collagen (AB-C) to increase the rate of anastomosis healing in experimental animals with peritonitis.

METHODS

This animal experimental study received ethics committee approval. The animals were divided into three groups of seven animals each; the first group was control, the second group was the fibroblast growth factor collagen group, and the third group was the antibiotic collagen group. Under anesthesia, more than 50% of the colonic lumen was opened 4-5 cm distal to the ileocecal junction to create a defect. Twenty-four hours later, primary anastomosis was performed. The second group had the anastomosis line covered with a cover containing FGF-C. The third group had the anastomosis line covered by material containing AB-C. The experiment was concluded on the postoperative 7th day, and the anastomosis burst pressure, tissue hydroxyproline level, and histopathological assessment were performed.

RESULTS

Though the burst pressure was higher in the experimental groups, it was not statistically significant. In the second and third groups, vascular proliferation and fibroblastic activity appeared to be better than in the control group. Hydroxyproline values were statistically significant in the experimental groups compared to the control group.

CONCLUSION

FGF-C and AB-C may have potential utility in anastomosis healing, especially in those susceptible to infection due to anastomosis leak.

Biogenic amines in the colon

The gastrointestinal (GI) tract contains the highest concentration of biogenic amines in the human body. Neurons located in the GI tract, modulated by biogenic amines and various peptide and non-peptide transmitters, are called Enteric Nervous System (ENS). That explains why many medications used in neurology and psychiatry present side effects from the gut. Serotonin (5-hyroxytrypatamine, 5-HT), 95% of which is synthesized in the gut, is the most important amine (beside epinephrine and norepinephrine) colon functionality but another substances such as histamine, dopamine and melatonin are also potent in modulating intestine’s actions. Over 30 receptors for 5-HT were described in the human body, and 5-HT3, 5-HT4 and 5-HT7 are known to have the highest influence on motility and are a potent target for the drugs for treatment GI disorders, such as Irritable Bowel Syndrome (IBS) and Inflammatory Bowel Diseases (IBD). Histamine is a key biogenic amine for pathogenesis of allergy also in the colon. Alteration in histaminergic system is found in patients with diarrhea and allergic enteropathy. Dopamine affects functions of the large intestine but its modulating actions are more presented in the upper part of GI tract. Melatonin is best known for regulating circadian circle, but may also be a potent anti-inflammatory agent within the gut. Despite many years of research, it seems that more studies are needed to fully understand human colon neurochemistry.

Does Intraperitoneal Chemotherapy Increase the Incidence of Anastomotic Leakage after Colorectal Cancer Surgery: A Systematic Review and Meta-Analysis

Purpose

To identify and evaluate the influence of intraperitoneal chemotherapy without hyperthermia (IC_wh) to the incidence of anastomotic leakage (AL) after colorectal cancer surgery.

Methods

A systematic review and meta-analysis were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses in order to review all studies investigating the relationship between IC_wh and AL in patients undergoing colorectal surgery. The primary outcome was overall incidence rate of anastomotic leakage.

Results

Four studies were included in the final review. IC_wh was associated with an overall increased risk of anastomotic leakage [OR 2.05 (1.06, 3.98), P = 0.03]. But there was no significant increased incidence rate when fluorouracil was implanted into the abdominal cavity for IC_wh [OR 2.48 (0.55, 11.10), P = 0.24].

Conclusions

This meta-analysis provides some evidence to suggest IC_wh may increase the incidence of postoperative AL in colorectal cancer. However, fluorouracil implantation for IC_wh does not increase the risk of AL, which seems to be a relatively safe method of IC_wh.

Effects of melatonin in wound healing of dental pulp and periodontium: Evidence from in vitro, in vivo and clinical studies

INTRODUCTION

Database research has revealed that melatonin has beneficial effects in pulpal and periodontal regeneration. Several studies reported protective effects of melatonin against inflammation in several organs including the heart, brain, and teeth. In addition to inflammation reduction, melatonin has been involved in tissue regeneration and wound healing. The aim of this review is to summarize the evidence from in vitro, in vivo and clinical studies on the effects of melatonin in wound healing of dental pulp and periodontium. This review gives a thorough summary of the possible role of melatonin in wound healing of dental pulp and periodontium in connection with anti-inflammatory and antioxidant effects, cell proliferation, and cell differentiation. Any contradictory evidence is also assessed.

METHODS

The PubMed database was searched for all research articles published before April 2020 with the search terms "melatonin" and "dental pulp". Articles with the search terms "melatonin", "periodontal disease" and "bone" published before October 2019 were also included. Non-English articles were excluded.

RESULTS

Melatonin has been shown to reduce inflammation, inhibit cell proliferation and regulate differentiation of pulp cells. Melatonin increased odontoblast activities, resulting in the differentiation in the dental pulp. However, melatonin did not initiate differentiation in undifferentiated pulp cells but seemed to have beneficial effects in periodontitis by promoting periodontium's wound healing.

CONCLUSION

Those findings suggest that melatonin could have beneficial effects on pulpal and periodontal cells under inflammatory conditions. However, discrepancies remain between in vitro and in vivo findings regarding the effect of melatonin on dental pulp and periodontium.

Role of melatonin in the treatment of COVID-19; as an adjuvant through cluster differentiation 147 (CD147)

COVID-19 caused by the SARS-CoV-2 outbreak quickly has turned into a pandemic. However, no specific antiviral agent is yet available. In this communication, we aimed to evaluate the significance of CD147 protein and the potential protective effect of melatonin that is mediated by this protein in COVID-19. CD147 is a glycoprotein that is responsible for the cytokine storm in the lungs through the mediation of viral invasion. Melatonin use previously was shown to reduce cardiac damage by blocking the CD147 activity. Hence, melatonin, a safe drug, may prevent severe symptoms, reduce symptom severity and the adverse effects of the other antiviral drugs in COVID-19 patients. In conclusion, the use of melatonin, which is reduced in the elderly and immune-compromised patients, should be considered as an adjuvant through its CD147 suppressor and immunomodulatory effect.

Intraoperative intraperitoneal chemotherapy increases the incidence of anastomotic leakage after anterior resection of rectal tumors

BACKGROUND

Intraoperative intraperitoneal chemotherapy is an emerging treatment modality for locally advanced rectal neoplasms. However, its impacts on postoperative complications remain unknown. Anastomotic leakage (AL) is one of the most common and serious complications associated with the anterior resection of rectal tumors. Therefore, we designed this study to determine the effects of intraoperative intraperitoneal chemotherapy on AL.

AIM

To investigate whether intraoperative intraperitoneal chemotherapy increases the incidence of AL after the anterior resection of rectal neoplasms.

METHODS

This retrospective cohort study collected information from 477 consecutive patients who underwent an anterior resection of rectal carcinoma using the double stapling technique at our institution from September 2016 to September 2017. Based on the administration of intraoperative intraperitoneal chemotherapy or not, the patients were divided into a chemotherapy group (171 cases with intraperitoneal implantation of chemotherapy agents during the operation) or a control group (306 cases without intraoperative intraperitoneal chemotherapy). Clinicopathologic features, intraoperative treatment, and postoperative complications were recorded and analyzed to determine the effects of intraoperative intraperitoneal chemotherapy on the incidence of AL. The clinical outcomes of the two groups were also compared through survival analysis.

RESULTS

The univariate analysis showed a significantly higher incidence of AL in the patients who received intraoperative intraperitoneal chemotherapy, with 13 (7.6%) cases in the chemotherapy group and 5 (1.6%) cases in the control group (P = 0.001). As for the severity of AL, the AL patients who underwent intraoperative intraperitoneal chemotherapy tended to be more severe cases, and 12 (92.3%) out of 13 AL patients in the chemotherapy group and 2 (40.0%) out of 5 AL patients in the control group required a secondary operation (P = 0.044). A multivariate analysis was subsequently performed to adjust for the confounding factors and also showed that intraoperative intraperitoneal chemotherapy increased the incidence of AL (odds ratio = 5.386; 95%CI: 1.808-16.042; P = 0.002). However, the survival analysis demonstrated that intraoperative intraperitoneal chemotherapy could also improve the disease-free survival rates for patients with locally advanced rectal cancer.

CONCLUSION

Intraoperative intraperitoneal chemotherapy can improve the prognosis of patients with locally advanced rectal carcinoma, but it also increases the risk of AL following the anterior resection of rectal neoplasms.

Effects of the Folk Medicinal Plant Extract Ankaferd BloodStopper on the Healing of Colon Anastomosis: An Experimental Study in a Rat Model

Objectives:

Ankaferd BloodStopper (ABS) is a topical hemostatic agent that modulates the inflammatory response and accelerates wound healing. The aim of this study was to determine the effects of ABS on the colon anastomosis wound healing in a rat model.

Methods:

Thirty-two Wistar albino rats were divided into four groups as follows: Group A (n=8), left colonic anastomosis plus ABS treatment (sacrificed on the 3^rd day); Group B (n=8) (control), left colonic anastomosis (sacrificed on the 3^rd day); Group C (n=8), left colonic anastomosis plus ABS treatment (sacrificed on the 7^th day); and Group D (n=8) (control), left colonic anastomosis (sacrificed on the 7^th day). All rats were sacrificed at the end of the experiment to assess the anastomosis integrity and the presence of perianastomosis abscesses, peritonitis, and adhesions. Additionally, the bursting pressure and hydroxyproline (OH-pyroline) levels were determined, and a histopathologic evaluation of the perianastomosis tissue was conducted.

Results:

The mean bursting pressure on Day 7 was significantly higher than that on Day 3 in the ABS group (p=0.017). Overall, the bursting pressure was higher in animals treated with ABS than in the control animals, although the difference was not statistically significant. The OH-pyroline levels of both ABS groups were significantly higher than in the control groups. The mean OH-pyroline level on Day 7 was higher than that on Day 3 in the ABS-treated animals (p=0.038).

Conclusion:

ABS increases collagen formation and neovascularization, and it has a positive impact during the colon anastomosis healing in an experimental model of wound healing.