Butyrate modulating effects on pro-inflammatory pathways in human intestinal epithelial cells.

Butyrate acts as energy source for intestinal epithelial cells and as key mediator of several immune processes, modulating gene expression mainly through histone deacetylation inhibition. Thanks to these effects, butyrate has been proposed for the treatment of many intestinal diseases. Aim of this study was to investigate the effect of butyrate on the expression of a large series of target genes encoding proteins involved in pro-inflammatory pathways. We performed quantitative real-time-PCR analysis of the expression of 86 genes encoding proteins bearing to pro-inflammatory pathways, before and after butyrate exposure, in primary epithelial cells derived from human small intestine and colon. Butyrate significantly down-regulated the expression of genes involved in inflammatory response, among which nuclear factor kappa beta, interferon-gamma, Toll like 2 receptor and tumour necrosis factor-alpha. Further confirmations of these data, including studies at protein level, would support the use of butyrate as effective therapeutic strategy in intestinal inflammatory disorders.

Ritonavir combination therapy restores intestinal function in children with advanced HIV disease.

OBJECTIVES: To investigate the intestinal absorptive processes in children with HIV infection before and after treatment with combination therapy that includes ritonavir. To test the hypothesis that combination therapy improves intestinal function. DESIGN: Intestinal function tests were performed in 10 children with advanced HIV disease at the enrollment and after 3 and 6 months of therapy with ritonavir combined with two HIV reverse transcriptase inhibitors. HIV viral load and CD4 cell counts were also determined; body weight was monitored. METHODS: The D-xylose absorption test, the steatocrit and the determination of fecal alpha1-antitrypsin concentration were used to evaluate carbohydrate and fat absorption, as well as fecal protein loss. Serum iron levels were measured to indirectly evaluate iron absorption. HIV-1 RNA-polymerase chain reaction (PCR) and immunofluorescence imaging were used to evaluate virologic and immunologic responses. RESULTS: In all, 9 children had carbohydrate malabsorption, 3 steatorrhea, 2 protein loss, and 7 iron deficiency. Most tests produced normal results after 3 months of therapy, and all abnormalities were abolished 6 months after institution of combination therapy. Mean results of each of four absorption tests were significantly changed on combination therapy. Viral load was progressively reduced and CD4 count was increased, with an inverse relationship. An evident shift of body weight pattern toward catch-up growth was observed in all children. CONCLUSIONS: Ritonavir combination therapy results in prompt and sustained restoration of intestinal function, which is associated with reduction in viral load, increase in CD4 counts, and gain in body weight.

Growth hormone stimulates, through tyrosine kinase, ion transport and proliferation in human intestinal cells.

BACKGROUND: Growth hormone (GH) stimulates intestinal growth and differentiation and promotes water and ion absorption in the rat intestine. Epidermal growth factor has similar effects, which involve tyrosine kinase activity. The effects of growth hormone on ion transport and cell growth and the role of tyrosine kinase in these effects were examined in a human-derived intestinal cell line (Caco-2). METHODS: For transport study, electrical parameters were measured in human intestinal Caco-2 cell monolayers mounted in Ussing chambers. Cell growth was monitored by counting and 3H-thymidine incorporation in the presence and absence of growth hormone. The role of tyrosine kinase was investigated by using its specific inhibitor genistein. RESULTS: The addition of growth hormone induced a rapid, Cl- -dependent, decrease in short-circuit current without affecting tissue conductance, which is consistent with an anion-absorptive effect. Incubation with growth hormone increased cell count by 85% and 3H-thymidine incorporation by 64% versus the count in control specimens. The absorptive and trophic effects of growth hormone were dose-dependent, and the maximum effective concentration was identical for each effect. Genistein blocked the growth hormone effect on ion transport and cell growth. CONCLUSIONS: Growth hormone stimulates ion absorption and cell growth in human enterocytes. Both effects result from a direct growth hormone-enterocyte interaction, and both require tyrosine kinase activity. Growth hormone may have therapeutic potential in intestinal diseases characterized by epithelial atrophy and loss of water and electrolytes.

Pancreatic dysfunction and its association with fat malabsorption in HIV infected children.

BACKGROUND: Nutrient malabsorption frequently occurs in HIV infected children, but very few studies have investigated exocrine pancreatic digestive capacity in these cases. AIMS: To investigate pancreatic function in HIV infected children and to determine whether faecal fat loss, a prominent feature of intestinal dysfunction, is associated with pancreatic dysfunction. PATIENTS: Forty seven children with HIV infection without apparent pancreatic disease and 45 sex and age matched healthy controls. METHODS: Pancreatic function was evaluated by measuring elastase 1 concentration and chymotrypsin activity in stools by ELISA and colorimetric methods, respectively. Intestinal function was evaluated by measuring fat and protein loss by the steatocrit method and by faecal alpha1 antitrypsin concentration. RESULTS: 14 (30%) had abnormal pancreatic function tests: seven had isolated elastase activity deficiency, three isolated chymotrypsin deficiency, and four pancreatic deficiencies in both enzymes. Patient enzyme values were significantly lower than those of controls. Low faecal pancreatic enzymes were not associated with symptoms. Twelve children had steatorrhoea and four had increased alpha1 antitrypsin. Steatorrhoea was significantly associated with reduced faecal pancreatic enzymes. There was a significant negative correlation between elastase 1 concentration and steatocrit. Children with pathological faecal elastase 1 or chymotrypsin values did not differ from the other HIV infected children with respect to nutritional and immunological status, stage of HIV disease, presence of opportunistic infections, or drug administration. CONCLUSIONS: Abnormal pancreatic function tests are a frequent feature of paediatric HIV infection; this condition is associated with steatorrhoea, which probably contributes to the disease.

Serum pancreatic enzymes in human immunodeficiency virus-infected children. A collaborative study of the Italian Society of Pediatric Gastroenterology and Hepatology.

BACKGROUND: Numerous studies have shown pancreatic disease in adult human immunodeficiency virus (HIV)-infected patients, but there are very few reports on pediatric patients. Our aim was to determine the prevalence of increased serum pancreatic enzyme levels and their relationship to clinical manifestations of acute pancreatitis in HIV-infected children. METHODS: Forty-seven consecutive, symptomatic HIV-infected children (24 male; median age, 7.3 years; range, 1-17 years) and 45 sex- and age-matched controls without gastroenterologic disease were enrolled. In all subjects serum total amylase, pancreatic amylase, and lipase were assayed with commercial kits. The following were recorded: disease progression (CDC class), nutritional status (weight Z-score), CD4 lymphocyte count, drug treatment during the previous 12 months, presence of opportunistic infections, clinical evidence of acute pancreatitis (increased serum pancreatic enzymes associated with vomiting, abdominal distention, and intolerance when eating). RESULTS: Ten of 47 HIV patients had increased serum total amylase values; however fewer patients had increased specific pancreatic enzymes: 6 of 47 for pancreatic amylase (range, 1.8- to 19.8-fold normal limit) and 7 of 47 for lipase (range, 1.4- to 4-fold normal limit). Values were normal in all controls. Two HIV patients with increased total amylase had clinically evident parotid inflammation. None of the patients with increased serum pancreatic amylase and/or lipase had clinical symptoms of acute pancreatitis. Regression analysis showed no correlation between increased serum pancreatic enzyme levels and disease progression (CDC class), immunologic status (CD4 count), nutritional status, drug administration, or opportunistic infections. CONCLUSIONS: Fifteen per cent of HIV-infected children had biochemical evidence of pancreatic involvement; however, this condition was unrelated to clinical signs of pancreatitis. Neither drug administration nor opportunistic infections seem to determine the increased serum pancreatic enzyme levels.

Enterotoxic effect of the vacuolating toxin produced by Helicobacter pylori in Caco-2 cells.

Preliminary clinical evidence suggests that Helicobacter pylori may be associated with diarrhea through its vacuolating toxin (VacA). To establish whether VacA induces intestinal secretion, epithelial damage, or both, purified pH-activated VacA was added to Caco-2 cell monolayers mounted in Ussing chambers, and electrical parameters were monitored. Mucosal addition of VacA induced an increase in short circuit current, consistent with enterotoxic effect. The effect was time- and dose-dependent and saturable. It was not found if the toxin was not pH-activated, added to the serosal side, or preheated. In cells preloaded with the Ca2+ buffering compound BAPTA/AM or with the Cl- channel inhibitor 5-nitro-2-3-(3-phenylpropylamino)benzoic acid, short circuit current did not change, indicating that VacA induces activation of Ca2+-dependent Cl- channels. VacA did not show cytopathic effects, as judged by tissue resistance. These results support the hypothesis that H. pylori may be associated with diarrhea through production of VacA.

Oral bacterial therapy reduces the duration of symptoms and of viral excretion in children with mild diarrhea.

BACKGROUND: Oral administration of live Lactobacillus casei strain GG is associated with the reduction of duration of diarrhea in children admitted to the hospital because of diarrhea. The purposes of this work were to investigate the clinical efficacy of oral administration of Lactobacillus in children with mild diarrhea who were observed as outpatients, and to see whether Lactobacillus GG can reduce the duration of rotavirus excretion. METHODS: Duration of diarrhea was recorded in 100 children seen by family pediatricians and randomly assigned to receive oral rehydration or oral rehydration followed by the administration of lyophilized Lactobacillus casei, strain GG. Rotavirus was looked for in the stools of all children and in those in whom results were positive, stools were examined again 6 days after the onset of diarrhea. RESULTS: In 61 children results were positive for rotavirus and in 39 results were negative. Duration of diarrhea was reduced from 6 to 3 days in children receiving Lactobacillus GG, with a similar pattern in rotavirus-positive and -negative children. Six days after the onset of diarrhea, stools in only 4 out of 31 children that received Lactobacillus GG were positive for rotavirus compared with positive findings in 25 out of 30 control subjects. CONCLUSIONS: Oral administration of Lactobacillus GG is effective in rotavirus-positive and rotavirus-negative ambulatory children with diarrhea. Furthermore, it reduces the duration of rotavirus excretion.

Enteric cryptosporidiosis in pediatric HIV infection.

BACKGROUND: Enteric cryptosporidiosis is a frequent problem in adults with human immunodeficiency virus (HIV) infection, but little is known of its features in children. The aim of this study was to investigate the incidence and the clinical features of cryptosporidiosis in HIV-infected children. METHODS: Thirty-five children with symptomatic HIV infection were screened every 2 months, and in case of diarrhea, for the presence of Cryptosporidium. Intestinal function tests were performed, and the fecal osmotic gap was measured in children with cryptosporidiosis. RESULTS: Seventy episodes of diarrhea occurred in 16 children in a median period of 17 months. Cryptosporidium was detected in five cases, all with full-blown acquired immunodeficiency syndrome. Cryptosporidiosis was significantly more protracted than any other form of diarrhea and was associated with dehydration and severe weight loss. Intestinal function was not modified during cryptosporidiosis. Osmotic gap values were consistent with secretory rather than osmotic diarrhea. In four cases, recovery was observed without specific treatment. CONCLUSIONS: Enteric cryptosporidiosis is a severe problem in advanced stages of HIV infection. It does not induce intestinal malabsorption. It induces diarrhea of secretory type. Recovery may be observed independently of therapy.

In vivo and in vitro effects of human growth hormone on rat intestinal ion transport.

It has been reported that: 1) ovine growth hormone stimulates intestinal water, sodium, and chloride absorption and 2) specific growth hormone receptors are present in the rat intestine. Aims of this work were to investigate the effects of acute administration of hGH on water and ion transport in the rat ileum in vivo and in vitro. In vivo, the absorption rates of water, sodium, chloride, and potassium were determined in the rat perfused ileum, during a basal period and after i.v. administration of 6 micrograms/kg recombinant DNA-derived hGH. In vitro, electrical parameters were measured before and after the hormone addition to the mucosal or the serosal side of rat ileal mucosa mounted in Ussing chambers. In vivo, growth hormone induced a rapid increase in the absorption rates of water, sodium, chloride, and potassium. In vitro, the serosal, but not the mucosal, addition of growth hormone induced a rapid decrease of transepithelial potential difference and of short-circuit current. The effect was time- and dose-dependent, saturable, but not reversible in the short time. The electrical effect was abolished in the absence of chloride, indicating that it was related, at least in part, to inhibition of basal active chloride secretion. Growth hormone also reduced the short-circuit current increase induced by the secretagogues Escherichia coli heat-stable enterotoxin, theophylline, and calcium ionophore A23187. These results indicate that hGH has a rapid absorptive effect that is related, at least in part, to a direct intestinal antisecretory mechanism. It also reduces active intestinal secretion induced by various secretagogues.

Human intestinal cryptosporidiosis: secretory diarrhea and enterotoxic activity in Caco-2 cells.

A cell line model to detect enterotoxic effect was used to test fecal specimens of patients with enteric cryptosporidiosis. Fecal samples were obtained from 11 patients with Cryptosporidium diarrhea, and osmotic gap was determined. Caco-2 cell monolayers grown on filters were mounted in Ussing chambers, and electrical parameters were measured before and after the addition of fecal supernatant. A significant increase in short-circuit current was seen in 9 of 11 specimens. The enterotoxic effect was time- and dose-dependent, saturable, and Cl(-)- and Ca(2+)-dependent. Fecal osmotic gap was consistent with secretory diarrhea in the 9 enterotoxin-positive but not in the 2 enterotoxin-negative samples. In conclusion, a cell line model for studying the pathophysiology of enteric cryptosporidiosis was established. Enterotoxic activity was observed in most patients with enteric cryptosporidiosis and was strictly associated with secretory diarrhea.

Enterotoxic effect of stool supernatant of Cryptosporidium-infected calves on human jejunum.

BACKGROUND/AIMS: The clinical pattern of cryptosporidial diarrhea suggests an enterotoxic mechanism. No evidence for this mechanism has been reported thus far. This study aimed to look for enterotoxic effect elaborated by Cryptosporidium. METHODS: The effects on human intestinal transport of stool supernatant of diarrheal calves infected with Cryptosporidium parvum were examined. Aliquots of centrifuged and filtered stools were added to the mucosal or serosal side of human jejunum obtained from patients undergoing surgery and mounted in Ussing chambers. Electrical parameters were recorded. Stool supernatants of uninfected calves served as a control. RESULTS: The mucosal addition of 2.5 mg protein of fecal supernatant from diarrheal calves induced a prompt and significant increase in short circuit current with no effects on tissue conductance. The serosal addition of this material and the addition of control supernatant to either side did not induce modifications of electrical parameters. The enterotoxic effect was dose-dependent and saturable. It was reversible by withdrawing the supernatant from the incubation medium. The electrical effect was chloride- and calcium-dependent and was sensitive to heating. CONCLUSIONS: An enterotoxic activity is present in the stools of Cryptosporidium-infected calves. This activity may be responsible for secretory diarrhea in humans.

Oral immunoglobulins for treatment of acute rotaviral gastroenteritis.

OBJECTIVE: Preliminary evidence has been reported on the antirotavirus effect of human serum immunoglobulin administered orally. The aim was to see whether such treatment might be effective in rotavirus acute gastroenteritis. METHODS: A prospective, double-blind, placebo-controlled study was performed. Ninety-eight children admitted with acute gastroenteritis were enrolled and randomly assigned to groups A (treated) and B (control). Children in group A received a single oral dose of 300 mg/kg body weight of human serum immunoglobulin. Parameters of efficacy were clinical condition, frequency and consistency of stools, duration of diarrhea, duration of viral excretion, and length of hospital stay. Antirotaviral activity was determined in the immunoglobulin preparation by a specific neutralization assay. RESULTS: Seventy-one of the 98 children enrolled had rotaviral gastroenteritis; 36 belonged to group A. Children who received immunoglobulin had significantly faster clinical improvement of clinical condition and stool pattern than control children. Mean total duration of rotaviral diarrhea was 76 hours in group A and 131 in group B (P < .01). Viral excretion lasted 114 and 180 hours, respectively (P < .01). Hospital stay was significantly reduced in children in group A. Neutralizing antibodies against rotavirus were detected in the immunoglobulin preparation. CONCLUSION: Oral administration of immunoglobulin is associated with a faster recovery from acute gastroenteritis and should be given to children hospitalized with this illness.

Clinical variability of cardio-facio-cutaneous syndrome: report of two additional cases.

We describe two new cases of cardio-facio-cutaneous (CFC) syndrome, and underline the clinical variability of the CFC phenotype in our two patients presenting with border-line psychomotor development. The first patient showed some additional clinical manifestations, such as cryptorchidism and scoliosis, and the second one had atypical skin lesions.

Comparative effects of atrial natriuretic peptide and E. coli heat-stable toxin on rat intestinal transport.

Conflicting data have been published in favor of or against a secretory effect of atrial natriuretic peptide (ANP) in the intestine. The reported effects resemble that of Escherichia coli heat-stable enterotoxin (ST). In this work the effects of ANP were studied in well established experimental systems and compared with that of ST. Both peptides induced a prompt secretion of water, Na, and Cl with no effects on K net transport in the in vivo rat perfused jejunum. The addition of ST, but not of ANP, evoked an increase of short circuit current in rat intestinal mucosa mounted in Ussing chambers. ST induced a significant increase in guanylate cyclase activity in intestinal homogenates, whereas ANP showed no effect. No binding sites for ANP were detected in basolateral or brush border membranes, nor in isolated enterocytes by a suction filtration technique. In conclusion, ANP acts as a short-lived intestinal secretagogue in the rat. Its mechanism of action is different from that of E. coli ST and appears to be indirect, since is not mediated by specific intestinal receptors and is not evident in vitro.