Effect of growth hormone treatment on the healing of left colonic anastomoses in protein-malnourished rats

Pharmacological interventions for improved colonic anastomotic healing: A meta-analysis

AIM: To identify pharmaceuticals for the prophylaxis of anastomotic leakage (AL), we systematically reviewed studies on anastomosis repair after colorectal surgery.

METHODS: We searched PubMed and EMBASE for articles published between January 1975 and December 2012. We included studies in English with the primary purpose of promoting healing of anastomoses made in the colon or rectum under uncomplicated conditions. We excluded studies on adverse events from interventions, nutritional interventions or in situ physical supporting biomaterials. The primary outcome was biomechanical strength or AL. We performed meta-analyses on therapeutic agents investigated by three or more independent research groups using the same outcome. The DerSimonian-Laird method for random effects was applied with P < 0.05.

RESULTS: Of the 56 different therapeutic agents assessed, 7 met our inclusion criteria for the meta-analysis. The prostacyclin analog iloprost increased the weighted mean of the early bursting pressure of colonic anastomoses in male rats by 60 mmHg (95%CI: 30-89) vs the controls, and the immunosuppressant tacrolimus increased this value by 29 mmHg (95%CI: 4-53) vs the controls. Erythropoietin showed an enhancement of bursting pressure by 45 mmHg (95%CI: 14-76). The anabolic compound growth hormone augmented the anastomotic strength by 21 mmHg (95%CI: 7-35), possibly via the up-regulation of insulin-like growth factor-1, as this growth factor increased the bursting pressure by 61 mmHg (95%CI: 43-79) via increased collagen deposition. Hyperbaric oxygen therapy increased the bursting pressure by 24 mmHg (95%CI: 13-34). Broad-spectrum matrix metalloproteinase inhibitors increased the bursting pressure by 48 mmHg (95%CI: 31-66) on postoperative days 3-4. In the only human study, the AL incidence was not significantly reduced in the 103 colorectal patients treated with aprotinin (11.7%) compared with the 113 placebo-treated patients (9.7%).

CONCLUSION: This systematic review identified only one randomized clinical trial and seven therapeutic agents from pre-clinical models that could be explored further for the prophylaxis of AL after colorectal surgery.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The effects of ghrelin on colonic anastomosis healing in rats

OBJECTIVES

In addition to its roles in the stimulation of growth hormone secretion and the regulation of appetite and metabolism, ghrelin exerts immunomodulatory, anti-inflammatory and antioxidant actions in several organ systems. In this study, we investigated the effects of ghrelin on the healing of experimental colonic anastomoses.

METHODS

Wistar rats were randomly divided into two groups (n = 10 in each). A segment of colon was excised, and an end-to-end anastomosis was performed in the distal colon. The Ghrelin Group received 10 ng/kg/day IP ghrelin for seven days postoperatively, whereas the Control Group received an identical volume of saline. On the seventh postoperative day, the anastomotic bursting pressures and hydroxyproline levels were measured, and adhesion formation around the anastomoses was examined. Histopathological analyses were performed to evaluate inflammatory cell infiltration, fibroblast infiltration, collagen density and neovascularization.

RESULTS

In the Ghrelin Group, the bursting pressure and hydroxyproline levels were significantly higher than in the Control Group. The adhesion formation scores were lower in the Ghrelin Group than in the Control Group. Although the inflammatory cell infiltration was diminished in the Ghrelin Group, the degrees of fibroblast infiltration, collagen density and neovascularization were not significantly different between the groups.

CONCLUSION

Our results indicate that ghrelin improves the healing of colonic anastomoses in rats.

Efeito da suplementação dietética de arginina na cicatrização das anastomoses colônicas em ratos

RACIONAL: A arginina, aminoácido condicionalmente essencial, participa de diversos processos fisiológicos, em particular na cicatrização e na função imune. OBJETIVO: Avaliar o efeito da suplementação por via oral da arginina na cicatrização colônica em ratos. MÉTODO: Foram utilizados 47 ratos Wistar machos, adultos, com peso médio de 345,45 ± 8,35g, alocados em gaiolas coletivas em grupos cinco ou seis animais. Todos receberam água e ração ad libitum, pesados a cada dois dias e randomizados para receberem por gavagem suplementação com arginina a 10% (grupo ARG) ou solução de aminoácidos a 10% (grupo AA) de forma isovolumétrica, isocalórica e isonitrogenada (1,5 g/kg/dia) por sete dias antes do procedimento operatório e quatro após. Um terceiro grupo recebeu solução salina isotônica (grupo SSI), isovolumetricamente. Os ratos foram submetidos a duas colônicas término-terminais confeccionadas 3 cm distais à válvula ileocecal e outra 5 cm distais à primeira, em plano único com fio monofilamentar de nylon 5-0, e foram sacrificados no 5º dia de pós-operatório Neste dia, as duas anastomoses foram ressecadas, sendo uma conservada em solução salina para medidas de tração e a outra enviada à anatomia patológica, para análise do colágeno (total, maduro e imaturo), e imunoistoquímica para a pesquisa de miofibroblastos e neovascularização. Foi avaliado o peso corpóreo ao longo do experimento. A análise estatística foi realizada com os testes t de Student e de Mann-Whitney. RESULTADOS: A comparação referente ao peso nos três grupos não evidenciou diferença significativa nos pesos iniciais, mas foi observada diferença entre os finais nos grupos SSI e AA (324,7g vs. 298g, P=0,04). A tensão foi significativamente maior no grupo AA quando comparado ao grupo SSI (0,94kgf/cm² vs 0,67 kgf/cm², P=0,04), mas não em relação ao grupo ARG (0,94kgf/cm² vs 0,70 kgf/cm², P=0,09). Quanto à força máxima de tração observou-se diferença significativa entre o grupo AA e o grupo SSI (0,18kgf vs 0,13 kgf, P=0,04) mas não em relação ao grupo ARG (0,18kgf vs 0,14 kgf, P=0,08). A força de ruptura total evidenciou valor significativamente maior para o grupo AA quando comparado ao grupo ARG (0,10kgf vs 0,06 kgf, P=0,05), mas não em relação ao grupo SSI (0,10kgf vs 0,09 kgf, P=0,54). Não foi observada diferença significativa quanto à concentração dos colágenos subtipo I e III e nem do índice de maturação de colágeno nos três grupos. Não foi observada também diferença significativa em relação à contagem de vasos sanguíneos ou miofibroblastos pela imunoistoquímica entre os três grupos. CONCLUSÃO: A administração de solução contendo 20 aminoácidos se mostrou mais efetiva do que a administração isolada de arginina nas provas de tração das anastomoses colônicas.

Effects of Cholerella sp. microalgae extract on colonic anastomosis in rats with protein-energy malnutrition

OBJECTIVE

Algae, which are used as supplementary nutrients in various countries, are products rich in protein, vitamins and minerals. The aim of this study was to investigate the effects of algae extracts on the healing of colonic anastomosis in malnourished rats.

METHOD

Seventy-two rats were randomized to three groups. Group 1 was fed with standard diet for 15 days, before and after the colonic anastomosis. Groups 2 and 3 were fed with a malnutrition diet for 15 days prior to colonic anastomosis and then with the basic diet for 15 days there after. Group 3 also received an extract of algae derived from Cholerella sp. via oral gavage postoperatively, in addition to the basic diet. Rats were killed on the 3rd, 7th and 15th postoperative day. Blood samples were collected to evaluate prealbumin, transferring and albumin levels. Anastomotic bursting pressures (BPs), histopathology and tissue hydroxyproline levels were evaluated after killing.

RESULTS

In group 3, the prealbumin level on the 3rd postoperative day and transferrin and albumin levels on the 7th and 15th postoperative days were significantly increased compared with the other groups (P < 0.05). Tissue hydroxyproline levels and anastomotic BPs of group 3 were significantly higher than in group 2 on the 3rd, 7th and 15th postoperative days (P < 0.05). Histopathological examination of the anastomosis revealed significantly better healing patterns for group 3 than for groups 1 and 2 (P < 0.05).

CONCLUSION

Extract derived from Cholerella sp. microalgae has favourable effects on healing of experimental colon anastomoses.

The effect of recombinant human growth hormone (rhGH) on trinitrobenzene sulfonic acid-induced colitis in rats: an experimental study

The limited efficacy of standard medical therapies for inflammatory bowel diseases has resulted in a continuing search for alternative treatments. Growth hormone (GH) has shown to have mutagenic and proliferative effects on intestinal cells. This study was designed to identify the effect of growth hormone on trinitrobenzene slfonic acid-induced colitis (TNBSIC) in rats. This study was carried out on 30 rats, divided in 3 groups: group 1: TNBSIC+ GH, group 2: TNBSIC, group 3: saline enema. Colitis was induced in male Sprague-Dawley rats (200 g-250 g) by intracolonic installation of 2, 4, 6-trinitrobenzene sulphonic acid in 50% ethanol. GH treatment has been started and continued throughout the study after inducing colitis. All rats were killed after 5 weeks and colonic segments were examined histopathologically. Microscopic and macroscopic damage scores were caulculated. Intestinal damage scores were found higher in Goups II when compared with treatment group (P < 0.05). There was no damage in group 3 as expected. Both macroscopic and microscopic scores were highest in group 2 (P < 0.05). The myloperoxidase activity was found lower comparing to group 2 (P < 0.05). In conclusion, growth hormone replacement had protective effects against colonic inflammation while reducing intestinal damage on TNB-induced colitis.

Effects of recombinant human growth hormone and nandrolone phenylpropionate on the healing of ischemic colon anastomosis in rats

PURPOSE

Recombinant human growth hormone and nandrolone phenylpropionate are two different anabolic agents. This study was designed to investigate the effects of these anabolic agents on the healing of ischemic colon anastomosis in rats.

METHODS

Seventy adult male Wistar rats were divided into five groups (n = 14). Group I was the sham laparotomy group. In the other groups, surgical procedures consisting of transsection and anastomosis were made at a distance 3 cm from the peritoneal reflection. Group II was the nonischemic control group. Ischemic colon model was produced in the remaining groups. Group III was the untreated control group. Groups IV and V received recombinant human growth hormone and nandrolone phenylpropionate, respectively. Bursting pressure and hydroxyproline levels were measured on the third and seventh postoperative days to evaluate anastomotic healing.

RESULTS

Recombinant human growth hormone increased both collagen deposition and bursting pressure significantly at postoperative Days 3 and 7 compared with the sham and untreated control groups (P < 0.005). When compared with the untreated control, nandrolone phenylpropionate significantly increased collagen deposition at postoperative Days 3 and 7 (P < 0.005) and bursting pressure only at postoperative Day 3 (P < 0.005).

CONCLUSIONS

Recombinant human growth hormone has more favorable therapeutic effects on the healing of ischemic colonic anastomoses than nandrolone phenylpropionate. Recombinant human growth hormone also improves healing of nonischemic colonic anastomosis.

Repair of full-thickness bowel injury

OBJECTIVE

Colon surgery is more and more often performed in complex situations such as after trauma, under immunosuppression, or in the elderly. Even under optimal conditions, anastomosis fails in certain situations. The objective of this study was to demonstrate the normal phases of bowel healing and to review the local and systemic factors affecting healing with special attention to critical care variables such as major surgery, acute hemorrhage, and infections.

DATA SOURCE

MEDLINE cited and/or published articles.

DESIGN

Review analysis.

RESULTS

Colon healing is a structured cascade of different phases that can be affected by a multitude of local (infection, ischemia) and systemic (diabetes, malnutrition, anemia, hypothermia, trauma) factors. The normal phases of repair, the resulting bursting pressure as an experimental index of healing, and the available published data on local and systemic factors affecting healing are summarized.

CONCLUSION

Several local and systemic factors negatively affect bowel healing; there is still a small portion of patients who fail to heal, suggesting that intrinsic factors need to be analyzed.

The future of nutrition and wound healing

Nutrition is vital to all bodily processes. During wound healing, it is essential that nutrients are available as they form the building blocks for tissue repair. Nutrition may therefore affect healing due to an overall deficiency of intake, either due to non-availability or due to inability of the patient to absorb sufficiently to meet their requirements. Alternatively, deficiencies of specific nutrients may also inhibit healing and on the converse some additives, not normally present in large quantity in the diet, may have beneficial effects. This review considers the nutritional factors affecting wound healing and some developments that may alter the future of therapy.

Are gastric, jejunal, or both forms of enteral feeding gastroprotective during stress?

BACKGROUND

Clinical data suggest enteral nutrition prevents stress ulceration and intragastric nutrients prevent restraint-induced gastric injury. The purpose of these studies was to determine if jejunal nutrients can protect without gastric contact and to determine if gastric pH, motility, or mucosal perfusion is affected.

METHODS

In Experiment 1, 27 rats were restrained for 2 h at room temperature followed by 2 h in cold (4 degrees C), with intragastric (IG) or intrajejunal (IJ) 2 ml/h infusions of saline or 25% glucose. Gastric lesions, pH, volumes, and glucose concentrations were measured postmortem. In Experiment 2, 23 rats had gastric strain gauges implanted >5 days prior to a 0.5 ml/h IG or IJ infusion during stress. In Experiment 3, 40 rats were anesthetized for laser Doppler measurements of gastric mucosal perfusion and arterial catheter monitoring of systemic hemodynamics. Rats received 0.5-ml boluses of concentrated glucose or saline IG or IJ, and were monitored for 60 min.

RESULTS

(1) The 2 ml/h IJ and IG glucose infusions prevented gastric injury, but the elevated gastric glucose concentrations suggested equal gastric contact. (2) The 0.5 ml/h glucose IG and IJ infusions decreased gastric injury without reflux of the IJ glucose into the stomach and suppressed stress-induced hypercontractility, but not acidity. (3) Systemic perfusion pressures were unaffected by enteral glucose. IG glucose had little effect on gastric mucosal perfusion, while IJ glucose decreased gastric perfusion within 5 min.

CONCLUSIONS

These studies show that large volumes of enteral glucose prevent restraint injury but IJ glucose refluxes into the stomach. The gastroprotective effects of small, nonrefluxing volumes of IJ glucose are associated with suppression of stress-induced gastric hypercontractility, but not with suppressed acidity or enhanced perfusion.