Comparison of interleukin-11 and epidermal growth factor on residual small intestine after massive small bowel resection

Cytoprotective gastric pentadecapeptide BPC 157 resolves major vessel occlusion disturbances, ischemia-reperfusion injury following Pringle maneuver, and Budd-Chiari syndrome

The stable gastric pentadecapeptide BPC 157 counteracts various venous occlusion-induced syndromes. Summarized are all these arguments, in the Robert’s cytoprotection concept, to substantiate the resolution of different major vessel occlusion disturbances, in particular ischemia-reperfusion injury following the Pringle maneuver and Budd-Chiari syndrome, which was obtained by BPC 157 therapy. Conceptually, there is a new point, namely, endothelium maintenance to epithelium maintenance (the recruitment of collateral blood vessels to compensate for vessel occlusion and reestablish blood flow or bypass the occluded or ruptured vessel). In this paper, we summarize the evidence of the native cytoprotective gastric pentadecapeptide BPC 157, which is stable in the human gastric juice, is a membrane stabilizer and counteracts gut-leaky syndrome. As a particular target, it is distinctive from the standard peptide growth factors, involving particular molecular pathways and controlling VEGF and NO pathways. In the early 1990s, BPC 157 appeared as a late outbreak of the Robert’s and Szabo’s cytoprotection-organoprotection concept, like the previous theoretical/practical breakthrough in the 1980s and the brain-gut axis and gut-brain axis. As the time went on, with its reported effects, it is likely most useful theory practical implementation and justification. Meantime, several reviews suggest that BPC 157, which does not have a lethal dose, has profound cytoprotective activity, used to be demonstrated in ulcerative colitis and multiple sclerosis trials. Likely, it may bring the theory to practical application, starting with the initial argument, no degradation in human gastric juice for more than 24 h, and thereby, the therapeutic effectiveness (including via a therapeutic per-oral regimen) and pleiotropic beneficial effects.

Mitotic activity, modulation of DNA processing, and purinergic signalling in the adult rat auditory brainstem following sensory deafferentation

A complex scenario of cellular network reorganization is caused by unilateral sensory deafferentation (USD) in the adult rat central auditory system. We asked whether this plasticity response involves mitosis. Immunohistochemistry was applied to brainstem sections for the detection and localization of mitotic markers Ki67 and PCNA, the growth-associated protein Gap43 and purine receptor P2X4. Fluorescent double staining was done for Ki67:PCNA and for both of them with HuC/HuD (neurons), S100 (astrocytes), Iba1 (microglia) and P2X4. Inquiring 1-7 days after USD, we found Ki67 expression to be changed in cellular profiles of cochlear nucleus (CN) with a significant increase in number by 1-3 days, followed by reset to control level within 1 week. USD-induced mitosis exclusively occurred in microglia and was absent elsewhere in the auditory brainstem. PCNA staining of small cellular profiles increased similarly but remained elevated. PCNA staining intensity also changed in CN, superior olive and inferior colliculus in neuronal nuclei, suggesting shifts in DNA processing. No apoptotic cell death was detected in any region of the adult auditory brainstem after USD. A comparison of anterograde and retrograde effects of nerve damage revealed proliferating microglia expressing P2X4 receptors in CN upon USD, but not in the facial nucleus after facial nerve transection. In conclusion, the deafferentation model studied here permits insight into the capacity of the adult mammalian brain to invoke mitosis among glia cells, adjustment of gene processing in neurons and purinergic signalling between them, jointly accounting for a multilayered neuro- and glioplastic response.

Is maintenance of the ileocecal valve important to the intestinal adaptation mechanisms in a weaning rat model of short bowel?

PURPOSE

To evaluate the role of maintenance of the ileocecal valve (ICV) in intestinal adaptation mechanisms, in a weaning rat experimental model of short bowel.

METHODS

Forty animals were operated on to produce short bowel syndrome. They were divided into five groups: maintenance (MV) or resection of ICV (RV), kill after 4 days (MV4 and RV4) or 21 days (MV21 and RV21), and a control group (21-day-old rats). Body weights, small bowel and colon lengths and diameters, villus heights, crypt depths, lamina propria and muscle layer thickness, as well as the apoptosis index of villi and crypts and expression of pro- and anti-apoptotic genes, were studied.

RESULTS

Preservation of the ICV promoted increased weight gain (p = 0.0001) and intestinal villus height after 21 days; crypt depth was higher in comparison to controls. It was verified a higher expression of Ki-67 in bowel villi and crypts (p = 0.018 and p = 0.015, respectively) in RV4 group and a higher expression in bowel villi of MV4 group animals (p = 0.03). The maintenance of ICV promoted late increased expression of the anti-apoptotic gene Bcl-XL in the colon (p = 0.043, p = 0.002, p = 0.01).

CONCLUSION

The maintenance of the ICV led to positive changes in this model.

Mechanisms of acetaminophen-induced liver necrosis

Although considered safe at therapeutic doses, at higher doses, acetaminophen produces a centrilobular hepatic necrosis that can be fatal. Acetaminophen poisoning accounts for approximately one-half of all cases of acute liver failure in the United States and Great Britain today. The mechanism occurs by a complex sequence of events. These events include: (1) CYP metabolism to a reactive metabolite which depletes glutathione and covalently binds to proteins; (2) loss of glutathione with an increased formation of reactive oxygen and nitrogen species in hepatocytes undergoing necrotic changes; (3) increased oxidative stress, associated with alterations in calcium homeostasis and initiation of signal transduction responses, causing mitochondrial permeability transition; (4) mitochondrial permeability transition occurring with additional oxidative stress, loss of mitochondrial membrane potential, and loss of the ability of the mitochondria to synthesize ATP; and (5) loss of ATP which leads to necrosis. Associated with these essential events there appear to be a number of inflammatory mediators such as certain cytokines and chemokines that can modify the toxicity. Some have been shown to alter oxidative stress, but the relationship of these modulators to other critical mechanistic events has not been well delineated. In addition, existing data support the involvement of cytokines, chemokines, and growth factors in the initiation of regenerative processes leading to the reestablishment of hepatic structure and function.

Growth factors: possible roles for clinical management of the short bowel syndrome

The structural and functional changes during intestinal adaptation are necessary to compensate for the sudden loss of digestive and absorptive capacity after massive intestinal resection. When the adaptive response is inadequate, short bowel syndrome (SBS) ensues and patients are left with the requirement for parenteral nutrition and its associated morbidities. Several hormones have been studied as potential enhancers of the adaptation process. The effects of growth hormone, insulin-like growth factor-1, epidermal growth factor, and glucagon-like peptide 2 on adaptation have been studied extensively in animal models. In addition, growth hormone and glucagon-like peptide 2 have shown promise for the treatment of SBS in clinical trials in human beings. Several lesser studied hormones, including leptin, corticosteroids, thyroxine, testosterone, and estradiol, are also discussed.

Gastric pentadecapeptide BPC 157 and short bowel syndrome in rats

The gastric pentadecapeptide BPC 157, which was shown to be safe as an antiulcer peptide in trials for inflammatory bowel disease (PL14736, Pliva), successfully healed intestinal anastomosis and fistula in rat. Therefore, we studied for 4 weeks rats with escalating short bowel syndrome and progressive weight loss after small bowel resection from fourth ileal artery cranially of ileocecal valve to 5 cm beneath pylorus. BPC 157 (10 microg/kg or 10 ng/kg) was given perorally, in drinking water (12 ml/rat/day) or intraperitoneally (once daily, first application 30 min following surgery, last 24 h before sacrifice). Postoperatively, features of increasingly exhausted presentation were: weight loss appearing immediately regardless of villus height, twofold increase in crypt depth and fourfold increase in muscle thickness within the first week, jejunal and ileal overdilation, and disturbed jejunum/ileum relation. In contrast, constant weight gain above preoperative values was observed immediately with BPC 157 therapy, both perorally and parenterally, and villus height, crypt depth, and muscle thickness [inner (circular) muscular layer] also increased, at 7, 14, 21, and 28 days. Moreover, rats treated with pentadecapeptide BPC 157 showed not different jejunal and ileal diameters, constant jejunum-to-ileum ratio, and increased anastomosis breaking strength. In conclusion, pentadecapeptide BPC 157 could be helpful to cure short bowel syndrome.

Resection-induced intestinal adaptation and the role of enteric smooth muscle

BACKGROUND

Intestinal adaptation after massive small bowel resection (SBR) involves all layers of the bowel wall. Most prior work has focused on changes that occur in the intestinal mucosa. However, the contribution of the underlying intestinal smooth muscle (ISM) to the overall adaptation response remains unclear.

METHODS

Male C57BL/6 or waved-2 (diminished activity of the epidermal growth factor receptor) mice underwent a 50% proximal SBR or sham operation, and the remnant ileum was harvested 3, 7, and 28 days. Markers of adaptation (villus height, bowel length, circumference, and ISM thickness) and ISM proliferation were recorded. Contractility was measured by attaching the distal ileum to strain gauge transducers and exposed to varying doses of carbachol.

RESULTS

Intestinal smooth muscle thickness was unchanged at any given time-point after resection; however, the bowel caliber and length were increased, and augmented rates of ISM proliferation were identified. Contractility was increased at 7 days after SBR. Waved-2 mice demonstrated minimal proliferation or intestinal lengthening in response to SBR.

CONCLUSION

Compared with resection-induced thickening of the mucosa, proliferative changes in the ISM are unique and primarily affect bowel caliber, length, and contractility. Epidermal growth factor receptor signaling appears to play a significant role in adaptation of the ISM cellular compartment.

Chronically administered retinoic acid has trophic effects in the rat small intestine and promotes adaptation in a resection model of short bowel syndrome

Following the loss of functional small bowel surface area, the intestine undergoes a compensatory adaptive response. The observation that adaptation is inhibited in vitamin A-deficient rats following submassive intestinal resection suggested that vitamin A is required for this response and raised the possibility that exogenous vitamin A could augment adaptation. Therefore, to directly assess whether chronically administered retinoic acid could stimulate gut adaptation in a model of short bowel syndrome and to address the mechanisms of any such effects, Sprague-Dawley rats were implanted with controlled release retinoic acid or control pellets and then subjected to mid-small bowel or sham resections. At 2 wk postoperation, changes in gut morphology, crypt cell proliferation and apoptosis, enterocyte migration, the extracellular matrix, and gene expression were assessed. Retinoic acid had significant trophic effects in resected and sham-resected rats. Retinoic acid markedly inhibited apoptosis and stimulated crypt cell proliferation and enterocyte migration postresection. Data presented indicate that these proadaptive effects of retinoic acid may be mediated via changes in the extracellular matrix (e.g., by increasing collagen IV synthesis, decreasing E-cadherin expression, and reducing integrin beta(3) levels), via affects on Hedgehog signaling (e.g., by reducing expression of the Hedgehog receptors Ptch and Ptch2 and the Gli1 transcription factor), by increasing expression of Reg1 and Pap1, and by modulation of retinoid and peroxisome proliferator-activated receptor signaling pathways. These studies are the first to demonstrate that retinoic acid can significantly enhance intestinal adaptation and suggest it may be beneficial in patients with short bowel syndrome.

Functional expression of the interleukin-11 receptor alpha-chain in normal colonic epithelium and colon cancer

BACKGROUND

Interleukin-11 (IL-11) has been evaluated as an anti-inflammatory and mucosa-protective therapeutic agent in inflammatory bowel diseases (IBDs). Activity of IL-11 requires binding to the alpha receptor subunit (IL-11Ralpha) that provides ligand specificity. Recently, we showed that in the intestinal mucosa, IL-11Ralpha is mainly present on epithelial cells mediating antiapoptotic effects. The aim of this study was to investigate the expression profiling of IL-11Ralpha and its downstream signaling cascade in colonic adenoma and carcinoma.

MATERIALS AND METHODS

The expression of IL-11Ralpha in normal colonic mucosa, 11 colonic adenomas, and 10 carcinomas was analyzed by immunohistochemistry. In addition, IL-11Ralpha-expression and IL-11Ralpha-induced phosphorylation of signal transducer and activator of transcription (STAT)3 were investigated by Western blot analysis.

RESULTS

Immunohistochemistry revealed significant IL-11-Ralpha expression in epithelial cells of normal colonic mucosa. In contrast, the expression of IL-11-Ralpha in colon adenomas and carcinomas was either absent or only detectable in very few scattered epithelial cells. Densitometric analysis of Western blots confirmed these results, showing a decrease of IL-11Ralpha-protein in cells isolated from adenomas or carcinomas. Reduced STAT3-phosphorylation in carcinoma cells indicated functional consequences of decreased IL-11Ralpha-protein expression on signal transduction.

CONCLUSION

This study demonstrates a decrease of IL-11-Ralpha-protein expression in epithelial cells isolated from colon carcinomas and adenomas compared to normal colonic mucosa and a reduced STAT3 signaling. Because of reduced binding and signal transduction, it is unlikely that therapeutically administered IL-11 would contribute to colorectal carcinoma induction and growth.

New growth factor therapies aimed at improving intestinal adaptation in short bowel syndrome

Short bowel syndrome (SBS) is used to describe a condition of malabsorption and malnutrition resulting from the loss of absorptive area following massive small bowel resection. The key to improved clinical outcome after massive small bowel resection is the ability of the residual bowel to adapt. Although still in experimental stages, a major goal in the management of SBS may be the augmented use of growth factors to promote increased adaptation. A number of growth factors have been implicated in promoting the adaptation process. The best-described growth factors are reviewed: glucagon-like peptide-2 (GLP-2), epidermal growth factor (EGF), and growth hormone (GH). This article reviews the ability of recombinant GLP-2, EGF and GH to modulate structural and functional aspects of intestinal adaptation following small bowel resection. Although these growth factors have shown promise, small sample size, inconsistent measurement parameters and uncontrolled study designs have hampered the acquisition of strong data advocating the use of growth factor treatment for SBS. Multicenter trials using well-defined outcome measures to assess clinical efficacy are needed to direct the clinical indications, timing and duration of therapy and assess potential risks associated with growth factor therapies.

Intestinal Adaptation in Short Bowel Syndrome

Short bowel syndrome occurs when there is insufficient length of the small intestine to maintain adequate nutrition and/or hydration status without supplemental support. This syndrome most frequently occurs following extensive surgical resection of the intestine, and the extent of adaptation depends on the anatomy of the resected bowel and the amount of bowel remaining. Following resection, the intestinal tissue undergoes morphologic and functional changes to compensate for the lost function of the resected bowel. These changes are mediated by multiple interactive factors, including intraluminal and parenteral nutrients, gastrointestinal secretions, hormones, cytokines, and growth factors, many of which have been well characterized in animal models. The amount of small bowel remaining is the most important predictor of adaptive potential; neither structural nor functional adaptative changes have been demonstrated in humans or animal models with more extreme resections resulting in an end-jejunostomy. The current understanding of these processes has led to the recent use of supplemental hormones, such as growth hormone and glucagon-like peptide 2, in intestinal rehabilitation programs and may lead to the development of pharmacologic agents designed to augment the innate adaptive response.

Intestinal adaptation after massive intestinal resection

Patients with short bowel syndrome require long term parenteral nutrition support. However, after massive intestinal resection the intestine undergoes adaptation and nutritional autonomy may be obtained. Given that the complications of parenteral nutrition may be life threatening or result in treatment failure and the need for intestinal transplantation, a more attractive option is to wean patients off nutrition support by optimising the adaptive process. The article examines the evidence that after extensive small bowel resection adaptation occurs in humans and focuses on the factors that influence adaptation and the strategies that have been used to optimise this process. The review is based on an English language Medline search with secondary references obtained from key articles. There is evidence that adaptation occurs in humans. Adaptation is a complex process that results in response to nutrient and non-nutrient stimuli. Successful and reproducible strategies to improve adaptation remain elusive despite an abundance of experimental data. Nevertheless given the low patient survival and quality of life associated with other treatments for irreversible intestinal failure it is imperative that clinical research continues into the optimisation of the adaptation.

Intestinal adaptation after massive intestinal resection

Patients with short bowel syndrome require long term parenteral nutrition support. However, after massive intestinal resection the intestine undergoes adaptation and nutritional autonomy may be obtained. Given that the complications of parenteral nutrition may be life threatening or result in treatment failure and the need for intestinal transplantation, a more attractive option is to wean patients off nutrition support by optimising the adaptive process. The article examines the evidence that after extensive small bowel resection adaptation occurs in humans and focuses on the factors that influence adaptation and the strategies that have been used to optimise this process. The review is based on an English language Medline search with secondary references obtained from key articles. There is evidence that adaptation occurs in humans. Adaptation is a complex process that results in response to nutrient and non-nutrient stimuli. Successful and reproducible strategies to improve adaptation remain elusive despite an abundance of experimental data. Nevertheless given the low patient survival and quality of life associated with other treatments for irreversible intestinal failure it is imperative that clinical research continues into the optimisation of the adaptation.

Epidermal growth factor and bombesin act synergistically to support intestinal adaptation in rats with massive small bowel resection

Intestinal adaptation is the most important event in short bowel syndrome following a massive small bowel resection. Effects of various growth factors and their synergism have been well documented in intestinal adaptation. This study aimed to compare the effect of two different trophic agents, epidermal growth factor (EGF) and bombesin (BBS), on intestinal adaptation following massive intestinal resection. Sprague-Dawley male rats were assigned to one of four groups after a 75% small bowel resection. Either EGF (90 microg/kg), BBS (10 microg/kg), EGF+BBS, or bovine serum albumin (BSA) were injected subcutaneously three times a day. The animals were killed 10 days after the operation. Weight loss and morphologic parameters such as mucosal thickness, villus height, crypt depth, villus-to-crypt ratio, and muscularis propria height were measured. In the EGF+BBS group, mucosal thickness was found to be significantly increased compared with the other study groups (p<0.05). Similarly, villus height was significantly increased only in the EGF+BBS group (p<0.05). In the BBS group, both villus height and mucosal thickness showed a slight increase, but the values were not statistically significant compared with the vehicle-treated group. There were no significant differences in any of the remaining parameters between the groups. The results of this study indicate that the gut hormones EGF and BBS act synergistically in facilitating the adaptive response of the remnant ileum to massive intestinal resection.

The effect of sustained and local administration of epidermal growth factor on improving bilateral testicular tissue after torsion

Epidermal growth factor (EGF) modulates Leydig cell proliferation, steroidogenesis, spermiogenesis, and Sertoli cell activity. It plays an important role in repairing ischemia-reperfusion injury in different tissues. The aim of this study was to evaluate the effects of sustained and local administration of EGF on improving bilateral testicular tissue after torsion. A total of 57 Wistar albino rats were used. For the EGF transport system, 1x2 cm gelatin films containing 2 microg EGF were used. Torsion was created by rotating the right testis 720 degrees in a clockwise direction for 4 h in all groups except the control group. Then, in the torsion group, bilateral orchiectomy was performed. After returning the torsioned ipsilateral testes to their normal state, the bilateral testes were wrapped by 1x2 cm unloaded gelatin films in the gelatin (G7 and G21) groups and, by 2 microg EGF loaded gelatin films in the EGF 7 and EGF 21 groups. The testes were removed on the seventh and 21st days, respectively, for biochemical and histological examination. Histologically, Johnsen's spermatogenesis criteria and mean seminiferous tubule diameter (MSTD) measurements were used. The EGF7 group did not show significant loss of Sertoli cells, while in the G7 group the number of these cells decreased. The ipsilateral ischemic testis of the EGF21 group showed Leydig cell hyperplasia, and the contralateral non-ischemic testes in this group were similar to the control group. In the G21 group, the bilateral testes showed Sertoli cell only syndrome in some sections, and most of the cells were undergoing apoptosis. The mean spermatogenesis scores and MSTD in the EGF7 and EGF21 groups were higher than in the G7 and G21 groups ( P<0.05). Malondialdehyde levels were significantly lower in the EGF groups than in the G groups ( P<0.05). Glutathione peroxidase (GSH-Px) levels in the G21 group were significantly higher than in the EGF21 group. Our study shows that local and sustained EGF release after testicular torsion improves bilateral testicular injury. EGF administration may be a new treatment choice for bilaterally injured testis after detorsion without removing the twisted testis.

Preventing enterocyte apoptosis after massive small bowel resection does not enhance adaptation of the intestinal mucosa

BACKGROUND

After massive small bowel resection (SBR), increased rates of enterocyte apoptosis are observed in the remnant bowel via a mechanism requiring bax gene expression. This study tested the hypothesis that adaptive mucosal growth could be enhanced by the novel strategy of preventing postresection enterocyte apoptosis.

METHODS

Male bax-null and corresponding wild-type (WT) mice underwent a 50% proximal SBR or sham operation (bowel transaction with reanastomosis alone). Mice were killed after a full adaptation interval of 1 month. Adaptation was measured in the remnant ileum as alterations in villus height, crypt depth, and wet weight. Rates of enterocyte proliferation were derived by immunostaining of crypt enterocytes for Ki-67 and apoptosis by the presence of apoptosis bodies.

RESULTS

The expected increase in enterocyte apoptosis after SBR occurred in the WT mice but was unchanged in the bax-null mice. Despite the prevention of postresection apoptosis in the bax-null mice, all parameters of adaptation and proliferation increased equally after SBR in both groups of mice.

CONCLUSIONS

Bax deficiency prevents the increase in enterocyte apoptosis that occurs after massive SBR throughout the entire adaptation period. Attenuation of postresection enterocyte apoptosis does not augment mucosal adaptation to massive intestinal loss.

Pharmacogenomic analysis of rhIL-11 treatment in the HLA-B27 rat model of inflammatory bowel disease

Recombinant human interleukin-11 (rhIL-11) reduces the clinical signs and histological lesions of inflammatory bowel disease (IBD) in transgenic rats expressing the human major histocompatability complex (MHC) class I allele, HLA-B27. To elucidate the pharmacogenomic effects of rhIL-11 in this model, we examined the global gene expression pattern in inflamed colonic tissue before and following rhIL-11 treatment using oligonucleotide microarrays. In total, 175 disease-related genes were identified. Increased expression of genes involved in antigen presentation, cell death and inflammation, and decreased expression of metabolic genes was associated with disease. A total of 27 disease-related genes returned to normal expression levels following rhIL-11 treatment including the MHC class II gene RT1-DMbeta. rhIL-11 induced the expression of four intestinal epithelial growth factors. These gene expression patterns indicate that treatment of inflammatory bowel disease with rhIL-11 affects class II antigen processing and colonic epithelial cell proliferation and metabolism.

Factors enhancing intestinal adaptation after bowel compensation

Intestinal failure (IF) refers to the condition in which certain causes lead to derangements in nutrient absorption capacity. Gut adaptation occurs in response to IF and it is both morphologic and physiologic in nature and can be mediated by growth factors and nutrients. Our paper reviews certain trophic growth factors that have important interactions relevant for intestinal growth, function and adaptation.

DATA SOURCE

The literature was reviewed (data from both animal and human studies) and certain trophic factors that modulate intestinal adaptation are summarized. The factors reviewed are: epidermal growth factor, insulin-like growth factor I and II, transforming growth factor alpha and beta, neurotensin, interleukin-11, glucagon-like peptide-2, keratinocyte growth factor, human growth hormone, short-chain fatty acids, and glutamine.

CONCLUSIONS

Growth factors augment intestinal proliferation, diminish programmed apoptosis, and modulate the adaptive process. They also have the potential to improve nutrient absorption in some bowel disease. The enhancement of gut adaptation may allow patients to transition of parenteral/enteral to normal nutrition, in a shorter period of time, which reduce the rate of adverse effects caused by artificial nutrition and improve quality of life.

IL-11 pretreatment reduces cell death after intestinal ischemia-reperfusion

BACKGROUND

Intestinal ischemia-reperfusion (IR) injury results in enterocyte necrosis and apoptosis. This study was designed to evaluate the potential protective effects of interleukin-11 (IL-11) pretreatment on intestinal mucosa following IR injury.

MATERIALS AND METHODS

Sham (n = 7) and control animals (n = 7) received 48 h of intravenous saline while treatment animals (n = 7) received IL-11 (750 microg/kg/day). Sham animals then underwent laparotomy alone, while control and treatment animals underwent 35 min of mesenteric artery occlusion and 120 min of reperfusion. Midjejunum samples were obtained and serum was drawn. Fluorometric assays were performed for hexosaminidase A (HEX A) and beta-glucuronidase (GLUC), markers of enterocyte necrosis. Apoptosis was quantified by TUNEL and confirmed by DNA fragmentation. Transcription of Bcl-2, an antiapoptotic regulator, was assessed by multiplex RT-PCR. Statistical analysis was performed using ANOVA and expressed as means +/- SEM.

RESULTS

In pretreated animals, HEX A and GLUC activities after IR were reduced from 570 +/- 54 to 426 +/- 47 nmol/ml/h (P < 0.05) and from 183 +/- 29 to 125 +/- 7 nmol/ml/h (P < 0.01), respectively. Pretreated animals had a reduced number of apoptotic cells per 10 crypts (79 +/- 11) compared with untreated rats (255 +/- 17) after IR injury (P < 0.01). Mucosal DNA from pretreated rats qualitatively showed less fragmentation on electrophoresis. Relative Bcl-2 band intensity was higher in pretreated animals (1.04 +/- 0.09) compared with controls (0.78 +/- 0.07) (P < 0.05).

CONCLUSIONS

IL-11 pretreatment reduced crypt cell apoptosis after IR injury, possibly by upregulating Bcl-2. Treated animals also demonstrated attenuation in the release of certain lysosomal enzymes. These data indicate that following IR injury, IL-11 improves enterocyte survival by reducing necrosis and apoptosis.

Epidermal growth factor improves nutritional outcome in a rat model of short bowel syndrome

BACKGROUND/PURPOSE

This study investigates the effect of epidermal growth factor (EGF) on nutrient absorption in a rat model of short bowel syndrome (SBS).

METHODS

Male juvenile rats underwent either transection (Sham) or ileocecal resection leaving a 20-cm jejunal remnant. Animals underwent follow-up for 10 days, and resected animals were treated with placebo or recombinant human EGF (1-53). Animals were pair fed; in vivo nutrient absorption, intestinal permeability, morphology, and total intestinal DNA and protein content were measured.

RESULTS

Resected EGF-treated animals lost significantly less weight than those in the placebo group (-4.2 +/- 3 v -13.7 +/- 6.9%), absorbed significantly more 3-0 methylglucose (76.8 +/- 6.6 v 64.9 +/- 10.1%), and had reduced permeability (lactulose/mannitol ratio, 0.35 +/- 0.19 v 0.60 +/- 0.20; P <.05 for all comparisons).

CONCLUSIONS

These findings show that treatment of short bowel syndrome animals with EGF reduced weight loss and improved carbohydrate absorption and intestinal permeability. These findings suggest that enteral EGF may be a useful therapy for short bowel syndrome; further studies are indicated.

The management of patients with the short bowel syndrome

The surgeon is invariably the primary specialist involved in managing patients with short bowel syndrome. Because of this they will play an important role in co-ordinating the management of these patients. The principal aims at the initial surgery are to preserve life, then to preserve gut length, and maintain its continuity. In the immediate postoperative period, there needs to be a balance between keeping the patient alive through the use of TPN and antisecretory agents and promoting gut adaptation with the use of oral nutrition. If the gut fails to adapt during this period, then the patient may require therapy with more specific agents to promote gut adaptation such as growth factors and glutamine. If following this, the patient still has a short gut syndrome, then the principal options remain either long term TPN, or intestinal transplantation which remains a difficult and challenging procedure with a high mortality and morbidity due to rejection.

Characterization of conditions for the primary culture of human small intestinal epithelial cells

Intestinal epithelial cells (IECs) are important for many aspects of gut physiology and pathology. Different approaches have been tried for the primary culture of human IECs, with varying degrees of success, as apoptosis easily occurs. Our aim was to develop a method for primary culture of human IECs from biopsy material. IECs and Lamina propria (LP) cells were liberated from duodenal biopsies obtained from subjects undergoing routine endoscopy for clinical investigations, whose small bowel was macroscopically normal. IECs were cultured on collagen membranes in a 12-well tissue culture cluster, with LP cells and allogeneic Epstein-Barr Virus (EBV)-transformed B lymphocytes (allo-B cells) underneath, in the well. Cultured IECs were characterized by light and confocal microscopy. Cytokine levels in culture supernatants were measured by ELISA. Cells showed the columnar morphology of IECs, even after several days in culture. Best results were obtained from IECs cultured above both LP and allo-B cells. IECs did not form monolayers as do transformed epithelial cell lines, but they did preserve their original cell-cell contacts. Analysis of culture supernatants showed that IL-10 was produced by IECs initially, but IL-1ra was produced by LP cells in the underlying wells with increasing time in culture. Very little IL-1 beta was produced from any cultures. These results show that IECs can be isolated and maintained in primary culture for a short while, which could open new possibilities for research using patient material instead of cell lines.

Recombinant human interleukin-11 prevents mucosal atrophy and bowel shortening in the defunctionalized intestine

BACKGROUND

Mucosal atrophy and bowel shortening are the hallmark of proximal intestinal diversion for extensive necrotizing enterocolitis (NEC) or Thiry-Vella fistulas (TVF), in which the ends of a defunctionalized loop of intestine are exteriorized as stomas. Recombinant human interleukin-11 (rhIL-11) is a pleiotropic cytokine that promotes epithelial regeneration and enhances adaptation after bowel resection. The authors hypothesized that rhIL-11 may prevent mucosal atrophy and bowel shortening in rats with TVF METHODS: After creation of ileal TVF, Sprague-Dawley rats were selected randomly to receive either rhIL-11 or equal volume of 0.1% bovine serum albumin (BSA) subcutaneously daily. On day 14, the TVF were excised and examined morphologically. Enterocyte apoptosis was measured using the TUNEL assay. Mucosal DNA and protein content were measured.

RESULTS

Administration of rhIL-11 resulted in a significantly greater weight gain and less shortening of TVF than BSA treatment. TVF from the rhIL-11-treated group showed evidence of hyperplasia and hypertrophy and increased crypt to villus ratio. The BSA group had substantial mucosal atrophy. There was a qualitative decrease in the incidence of apoptosis in the rhIL-11 group.

CONCLUSIONS

Recombinant human IL-11 prevents mucosal atrophy and shortening of defunctionalized intestinal loops. It may help reduce the incidence of short gut syndrome in infants with extensive NEC.

The primacy of the gastrointestinal tract as a target organ of acute graft-versus-host disease: rationale for the use of cytokine shields in allogeneic bone marrow transplantation

Acute graft-versus-host disease (GVHD), the major complication of allogeneic bone marrow transplantation (BMT), limits the application of this curative but toxic therapy. Studies of inflammatory pathways involved in GVHD in animals have shown that the gastrointestinal (GI) tract plays a major role in the amplification of systemic disease. Damage to the GI tract increases the translocation of inflammatory stimuli such as endotoxin, which promotes further inflammation and additional GI tract damage. The GI tract is therefore critical to the propagation of the “cytokine storm” characteristic of acute GVHD. Experimental approaches to the prevention of GVHD include reducing the damage to the GI tract by fortification of the GI mucosal barrier through novel “cytokine shields” such as IL-11 or keratinocyte growth factor. Such strategies have reduced GVHD while preserving a graft-versus-leukemia effect in animal models, and they now deserve formal testing in carefully designed clinical trials.

Effect of growth hormone, epidermal growth factor, and insulin on bacterial translocation in experimental short bowel syndrome

BACKGROUND/PURPOSE

An adaptive process starts in the remaining intestine after massive resection, and several trophic factors including growth hormone (GH), epidermal growth factor (EGF), and insulin (INS) have been shown to have a positive effect on it. Bacterial translocation (BT) is frequent after extensive small bowel resection, but the effects of GH, EGF, or INS have not been investigated in experimental short bowel syndrome (SBS). This study tests the hypothesis that GH, EGF, or INS decrease BT in SBS in rats with parenteral nutrition (PN).

METHODS

Thirty-eight adult Wistar rats underwent central venous cannulation and were assigned randomly to 1 of 4 groups receiving for 10 days 4 treatment regimes: (1) PN group (n = 10): fasting, all-in-one PN solution (300 mL/kg/24 h, 280 kcal/kg/24 h), 80% gut resection including ileo-cecal valve; (2) GH group (n = 9): fasting, same PN regime and resection, GH (1 mg/kg/d, subcutaneously); (3) EGF group (n = 9): fasting, PN, resection, EGF (150 microg/24 h intravenously); (4) INS group (n = 9): fasting, PN, resection, INS (1 UI/100 g/24 h subcutaneously). At the end of the experiment they were killed, and mesenteric lymph nodes (MLN) and peripheral and portal blood samples were recovered and cultured. Several fragments of intestine were taken to determine cell proliferation (PCNA index) and morphometric parameters (villous height, crypt depth).

RESULTS

GH, EGF, and INS groups showed a 28%, 29%, and 30% increase in gut mucosal thickness, and PCNA index rose 21%, 20%, and 25%, respectively in comparison with PN controls. Bacterial translocation to peripheral blood was detected in 0% of PN animals and in 44%, 40%, and 28% of GH, EGF, or INS rats, respectively (P < .05). No differences were found in BT in MLN or portal blood among groups.

CONCLUSION

Administration of GH, EGF, or INS improves gut mucosal structure in rats with SBS under PN, but, surprisingly, the incidence of BT detected in peripheral blood was increased rather than decreased in animals receiving these treatments.

Interleukin-11 enhances small intestine absorptive function and mucosal mass after intestinal adaptation

BACKGROUND/PURPOSE

Interleukin-11 (IL-11) recently has been shown to enhance mucosal mass after massive small bowel resection (MSBR). However, enhanced mucosal mass may not correlate with increased substrate absorption. This study was designed to examine the effect of systemic administration of increasing doses of IL-11 on small intestine absorptive function and mucosal mass after MSBR.

METHODS

Twenty-five Sprague-Dawley rats underwent an 80% small bowel resection and end-to-end jejunoileal anastomosis. Seven days after resection, all rats had placement of a jugular venous catheter connected to a subcutaneously placed osmotic pump. The rats were divided into 5 groups based on the content of the pump: group 1 (control, n = 5) received 0.1% bovine serum albumin (BSA) and groups 2 through 5 (n = 5 each) received IL-11 at 250, 500, 750, and 1,000 microg/kg/d, respectively. After a 14-day infusion period, [14C] galactose and [14C] glycine absorption was measured using an in vivo closed-recirculation technique. Mucosal DNA content also was determined for each group. Statistical analysis was performed by analysis of variance and expressed as mean +/-SEM.

RESULTS

IL-11 administered at 250 microg/kg/d, a dose used in previous studies, did not significantly affect substrate absorption. However, compared with the control group, administration of higher doses of IL-11 produced a significant increase in substrate absorption and mucosal mass. The dose of IL-11 producing the overall optimal response based on the parameters measured (galactose absorption, 72% increase over control; glycine absorption, 112% increase over control; and DNA content, 98% increase over control) was 750 microg/kg/d.

CONCLUSIONS

In addition to an increase in mucosal mass, these data show for the first time that IL-11 enhances absorptive function beyond the normal adaptive response after MSBR. Furthermore, the maximum effect of IL-11 on absorptive function was shown at 750 microg/kg/d, which is 3 times the dose used in previously reported studies. This study suggests that IL-11 may be useful clinically in patients with inadequate intestinal function.

Epidermal growth factor, epidermal growth factor receptors, intestinal growth, and adaptation

Epidermal growth factor (EGF) is an important constituent of several gastrointestinal secretions. Many studies in both animals and humans have shown EGF to have multiple effects upon gut epithelial cells. These include cytoprotection, stimulatory effects on cell proliferation and migration, induction of gene expression such as mucosal enzymes and trefoil proteins, and inhibitory effects on gastric acid secretion. The main conundrum associated with EGF action is the disparity between experimental studies on its luminal and systemic actions. Opinion is sharply divided as to whether or not EGF has any action when given luminally and on the site of the EGF receptors on gut epithelial cells. Most studies agree that the EGF receptors are located on the basolateral surface, in which case EGF should only be active if surface ulceration has occurred--unless there is translocation across the epithelium. There are several clinical situations in which EGF might be useful in cytoprotection and in stimulating repair and regeneration in the gut. These include necrotizing enterocolitis and mucositis, and it is to be hoped that the solid basis of experimental studies on EGF might stimulate work on this topic.

Long-term outcome of short bowel syndrome in adult and pediatric patients

We reviewed 12 pediatric and 18 adult patients with short bowel syndrome (SBS) from Osaka University Hospital and compared clinical characteristics between them. The length of the residual small intestine ranged from 0 to 75 cm (mean 47 cm) in pediatric patients and from 0 to 150 cm (mean 47 cm) in adult patients. In all cases, total parenteral nutrition (TPN) was started immediately after surgery and was gradually replaced by enteral nutrition. Eight pediatric patients (67%) and 4 adult patients (22%) were weaned from TPN. Residual intestinal length in these patients ranged from 27 to 75 cm (mean 57 cm) in pediatric patients and 57 to 150 cm (mean 96 cm) in adult patients. Pediatric patients with residual small intestinal lengths of 0, 16, 25, and 45 cm were not weaned from TPN. None of the adult patients with residual small intestinal length less than 40 cm could achieve complete intestinal adaptation. Five adult patients died due to liver failure (2 cases), heart failure (2 cases), or pneumonia (1 case), whereas all pediatric patients survived. The average life span of indwelling central venous catheters was 511 days and 780 days, and the rate of catheter-related sepsis per 1000 catheter days was 0.73 and 0.48 in pediatric and adult patients, respectively. Plasma levels of arginine and citrulline in patients receiving TPN were significantly decreased compared with those in patients receiving TPN without SBS both in pediatric and adult patients (p < .01). These results indicate that pediatric and adult patients with SBS can survive with TPN and enteral nutrition. The minimum remaining intestinal length necessary for complete bowel adaptation is shorter for pediatric patients than adults, suggesting better bowel adaptation in pediatric patients.

Interleukin-11: its biology and prospects for clinical use

IL-11 is a multifunctional cytokine that has pleiotropic effects on a variety of tissue including the bone marrow and intestinal mucosa. IL-11 is useful in elevating the platelet count in cancer patients with chemotherapy-induced thrombocytopenia and has a cytoprotective effect on the bowel mucosa in a variety of causes of gut damage and a trophic effect on the villi after massive bowel resection.

Epidermal growth factor and the short bowel syndrome

Because epidermal growth factor (EGF) has multiple effects on the intestinal epithelium and endogenous EGF plays an important role in maintaining normal intestinal structure and the response to injury, EGF should be important in the intestinal adaptive response to resection. The accumulated data in the literature support a role for endogenous EGF in the intestinal adaptive response. Endogenous EGF is increased in saliva and diminished in urine after intestinal resection. This suggests increased tissue utilization of endogenous EGF during adaptation. Intestinal EGF receptor activity is increased after resection. Intestinal adaptation is impaired in animals with defective EGF receptors. Thus EGF receptor activity also is important during adaptation. The results of experimental studies suggest that EGF administered at the time of resection enhances the intestinal adaptive response. Both structural and functional adaptation are augmented. The route, dose, and timing of EGF administration are important factors. EGF has additive effects with glutamine and growth hormone on adaptation. Several observations from these reports have relevance to the potential clinical application of EGF therapy: (1) EGF should be given soon after resection; (2) early transient administration may lead to a substantial effect on adaptation; (3) both systemic and enteral therapy may be effective; (4) luminal nutrients are important but not essential in mediating EGF-stimulated adaptation; and (5) combined therapy with other nutrients and growth factors may have merit. In conclusion, endogenous EGF plays an important role in intestinal adaptation. Furthermore, experimental results suggest the potential clinical usefulness of EGF to stimulate intestinal adaptation after massive intestinal resection. There is currently no evidence to support the use of EGF in patients with well-adapted short bowel syndrome.

Supportive care in hematological malignancies: hematopoietic growth factors, infections, transfusion therapy

This article focuses on a selected number of topics among recent developments in the supportive care of hematological malignancies. The first section focuses on the role of hematopoietic growth factors, such as granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, thrombopoietin, interleukin-11, and keratinocyte growth factor. The following sections discuss the management of fungal and viral infections as well as changes in the current policies of platelet transfusion. The focus of this review is on the clinical utility and economic feasibility of the published findings.