A flow cytometry method for safe detection of bacterial viability.

Flow cytometry is a relevant tool to meet the requirements of academic and industrial research projects aimed at estimating the features of a bacterial population (e.g., quantity, viability, activity). One of the remaining challenges is now the safe assessment of bacterial viability while minimizing the risks inherent to existing protocols. In our core facility at the Paris-Saclay University, we have addressed this issue with two objectives: measuring bacterial viability in biological samples and preventing bacterial contamination and chemical exposure of the staff and cytometers used on the platform. Here, we report the development of a protocol achieving these two objectives, including a viability labeling step before bacteria fixation, which removes the risk of biological exposure, and the decrease of the use of reagents such as propidium iodide (PI), which are dangerous for health (CMR: carcinogenic, mutagenic, and reprotoxic). For this purpose, we looked for a non-CMR viability dye that can irreversibly label dead bacteria before fixation procedures and maintain intense fluorescence after further staining. We decided to test on the bacteria, eFluor Fixable Viability dyes, which are usually used on eukaryotic cells. Since the bacteria had size and granularity characteristics very similar to those associated with flow cytometry background signals, a step of bacterial DNA labeling with SYTO or DRAQ5 was necessarily added to differentiate them from the background. Three marker combinations (viability-DNA) were tested on LSR Fortessa and validated on pure bacterial populations (Gram+ , Gram- ) and polybacterial cultures. Any of the three methods can be used and adapted to the needs of each project and allow users to adapt the combination according to the configuration of their cytometer. Having been tested on six bacterial populations, validated on two cytometers, and repeated at least two times in each evaluated condition, we consider this method reliable in the context of these conditions. The reliability of the results obtained in flow cytometry was successfully validated by applying this protocol to confocal microscopy, permeabilization, and also to follow cultures over time. This flow cytometry protocol for measuring bacterial viability under safer conditions also opens the prospect of its use for further bacterial characterization.

Iatrogenic constipation in gastrointestinal surgery.

Postoperative constipation occurs relatively frequently, and can involve drug-related, surgical and lifestyle and dietary factors. Gastrointestinal motility can be altered by inflammation, surgery, opioid medications, hypnotics, anti-secretory or anesthetic drugs or by functional modifications for which the physiopathology is not well defined. There are a number of laxatives available. These include bulk laxatives, osmotic laxatives and locally acting laxatives such as suppositories and enemas. Stimulant laxatives have a role to play in the short-term management of persistent constipation. 5-HT4 receptor antagonists are recommended in refractory constipation. Other specific therapeutic laxatives can be proposed such as methylnaltrexone in opioid-induced constipation or neostigmine in Ogilvie's syndrome. The prevention and/or early detection of iatrogenic constipation, whether postoperative or not, is essential and the knowledge how to improve patient comfort and reduce the duration of gastrointestinal motor disorders with specific drugs or other means is essential, particularly the postoperative period.

Intestinal microbiota contributes to individual susceptibility to alcoholic liver disease.

OBJECTIVE: There is substantial inter-individual diversity in the susceptibility of alcoholics to liver injury. Alterations of intestinal microbiota (IM) have been reported in alcoholic liver disease (ALD), but the extent to which they are merely a consequence or a cause is unknown. We aimed to demonstrate that a specific dysbiosis contributes to the development of alcoholic hepatitis (AH). DESIGN: We humanised germ-free and conventional mice using human IM transplant from alcoholic patients with or without AH. The consequences on alcohol-fed recipient mice were studied. RESULTS: A specific dysbiosis was associated with ALD severity in patients. Mice harbouring the IM from a patient with severe AH (sAH) developed more severe liver inflammation with an increased number of liver T lymphocyte subsets and Natural Killer T (NKT) lymphocytes, higher liver necrosis, greater intestinal permeability and higher translocation of bacteria than mice harbouring the IM from an alcoholic patient without AH (noAH). Similarly, CD45+ lymphocyte subsets were increased in visceral adipose tissue, and CD4(+)T and NKT lymphocytes in mesenteric lymph nodes. The IM associated with sAH and noAH could be distinguished by differences in bacterial abundance and composition. Key deleterious species were associated with sAH while the Faecalibacterium genus was associated with noAH. Ursodeoxycholic acid was more abundant in faeces from noAH mice. Additionally, in conventional mice humanised with the IM from an sAH patient, a second subsequent transfer of IM from an noAH patient improved alcohol-induced liver lesions. CONCLUSIONS: Individual susceptibility to ALD is substantially driven by IM. It may, therefore, be possible to prevent and manage ALD by IM manipulation.

[Nonalcoholic fatty liver disease in a severely obese adolescent. An arguable liver biopsy]. / Stéatohépatite non alcoolique chez une adolescente obèse: une biopsie hépatique discutable.

The growing epidemic of juvenile obesity has prompted pediatricians to investigate obesity-related conditions in obese teenagers. We report a clinical case of severe hepatic fibrosis in an adolescent with severe and recent obesity. Because of elevated serum aminotransferase levels, abnormal hepatic ultrasonography and insulin resistance (impaired glucose tolerance), we suspected nonalcoholic steatohepatitis (NASH). Disease activity and fibrosis were confirmed on liver biopsy. Considering the risk of progression toward cirrhosis and its complications, and the pathological liver lesions, we started long-term medical monitoring and drug therapy to control weight loss. At present, although biopsy is the only validated way to establish the diagnosis of NASH, there is no consensus on its indication when NASH is suspected. Noninvasive strategies are attractive but require validation in children.

High glucose and hyperinsulinemia stimulate connective tissue growth factor expression: a potential mechanism involved in progression to fibrosis in nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) may progress to liver fibrosis and cirrhosis. Mechanisms directly involved in the development of fibrosis have been poorly investigated. Because connective tissue growth factor (CTGF) is an intermediate key molecule involved in the pathogenesis of fibrosing chronic liver diseases and is potentially induced by hyperglycemia, the aims of this study were to (1) study the expression of CTGF in vivo both in human liver biopsy specimens of patients with NASH and in an experimental model of obesity and type II diabetes (Zucker rats); and (2) analyze the effects of hyperglycemia and insulin in vitro on hepatic stellate cells. In vivo, CTGF overexpression was observed in the liver tissue of all of the 16 patients with NASH. CTGF immunostaining was mild in 7 cases (44%) and moderate or strong in 9 cases (56%). Staining was mainly detected in the liver extracellular matrix in parallel with the amount of liver fibrosis. Liver from fa/fa rats also showed CTGF overexpression by comparison with Fa/fa rats both at the messenger RNA (mRNA) level (3-fold increase) and protein level. In vitro, both CTGF mRNA and protein were significantly increased when hepatic stellate cells were incubated with either glucose or insulin. A slight increase in type I procollagen mRNA level was also observed in hepatic stellate cells incubated with glucose. In conclusion, this study suggests that hyperglycemia and insulin are key-factors in the progression of fibrosis in patients with NASH through the up-regulation of CTGF.

Cryptogenetic multifocal ulcerous stenosing enteritis: an atypical type of vasculitis or a disease mimicking vasculitis.

BACKGROUND/AIMS: Cryptogenetic multifocal ulcerous stenosing enteritis (CMUSE) is a rare disease whose origin is unknown. The aim of this study was to describe the clinical spectrum of CMUSE, to determine the origin and pathophysiology of the disease, and to propose a treatment strategy. METHODS: A total of 220 French gastroenterology departments were contacted to review patients with unexplained small bowel strictures. Of 17 responses, 12 corresponded to a diagnosis of CMUSE. These patients were hospitalised between 1965 and 1993 and their medical records were reviewed. RESULTS: All patients (mean age 42.1 (4.4) years) had intestinal and five had extraintestinal symptoms (peripheral neuropathy, buccal aphthae, sicca syndrome, polyarthralgia, Raynaud's phenomenon, arterial hypertension). One patient had heterozygous type I C2 deficiency (28 base pair gene deletion). Two to 25 (mean 8.3 (1.9)) small intestine strictures were found. Stenoses of the large jejunoileal arteries were observed on two and aneurysms on three of five mesenteric angiograms. Despite surgery, symptoms recurred in seven of 10 patients and strictures in four. Steroid therapy was effective but caused dependence. One untreated patient died. Small bowel pathology showed superficial ulceration of the mucosae and submucosae, and an inflammatory infiltrate made of neutrophils and eosinophils. CONCLUSIONS: CMUSE is an independent entity characterised by steroid sensitive inflammation of the small bowel which often recurs after surgery. CMUSE may be related to a particular form of polyarteritis nodosa with mainly intestinal expression or with an as yet unclassified vasculitis.

[Treatment of chronic viral hepatitis B with lamivudine]. / Le traitement des hépatites chroniques virales B par la lamivudine.

INTERFERON ALPHA AND LAMIVUDINE: Chronic hepatitis B is currently treated with interferon alpha and lamivudine. Lamivudine (marketed under the name Zeffix in France) is given in oral preparations and is excreted in the urine. It is rapidly effective against virus replication since, after a one-month treatment, hepatitis B DNA levels are negative in most of the treated patients. After 12 months, there is an improvement in liver histology. ADVANTAGES AND DISADVANTAGES: The probability of effective treatment is greatest for patients with highly elevated transaminase levels and low hepatitis B DNA levels prior to treatment. Another advantage of lamivudine is the extremely low rate of side effects. The risk of a rebound in viral replication after withdrawal is a drawback together with the possible development of viral mutations of the polymerase gene, particularly after more than one year of treatment. INDICATIONS: Lamivudine can be prescribed for patients with a contraindication or non-responsive to alpha interferon: liver transplantation candidates, organ graft recipients. For other cases, alpha interferon is the first line treatment of choice. If lamivudine is used too early, there is a risk the patients could no longer be transplanted after the development of mutations and major aggravation of liver function. Future perspectives include simultaneous or sequential use of antiviral agents.

[Epithelioid hemangioendothelioma associated with nodular regenerative hyperplasia]. / Hémangioendothéliome épithélioïde associé à une hyperplasie nodulaire régénérative.

Epithelioid hemangioendothelioma of the liver is a rare neoplasm of vascular origin. We report a case of epithelioid hemangioendothelioma occurring in a patient with nodular regenerative hyperplasia. This association suggests that some hepatic vascular changes might promote the growth of epithelioid hemangioendothelioma.

Hepatitis C virus core protein binds to apolipoprotein AII and its secretion is modulated by fibrates.

Several lines of evidence suggest that hepatitis C virus (HCV) core protein may modulate cellular transduction signals and alter lipid metabolism. We have investigated the binding of HCV core protein to cellular proteins by combining 2 yeast hybrid, confocal, and surface plasmon resonance assays. Our results show the direct binding of the viral protein to apolipoprotein AII (apoAII) and map the interaction domain to the C-terminal of HCV core protein. To investigate the biological relevance of the interaction between HCV core and lipid metabolism, we took advantage of the well-established increase in apoAII expression caused by fibrates in HepG2 cells. After fenofibric acid treatment, we show a parallel increase in apoAII and core protein secretion, this effect being abolished by brefeldin A. Our study identifies apoAII as one of the cellular targets for HCV core protein. We also show that the intervention of fenofibric acid in cellular lipid metabolism directly affects the expression pattern of HCV core protein.

Octreotide treatment of chronic intestinal pseudoobstruction secondary to connective tissue diseases.

Chronic intestinal pseudoobstruction (CIPO) is a rare syndrome that may occur in association with connective tissue diseases (CTD). Effective management is a major challenge. We report 3 cases in which subcutaneous octreotide was efficacious in the treatment of digestive symptoms in CIPO. In 2 of the 3 cases, previous treatment with domperidone, cisapride, or erythromycin had been unsuccessful. All 3 patients underwent a regimen of oral antibiotics along with octreotide to stimulate small bowel motility. The effects of octreotide were evident within 48 hours after the first injection in all patients. In 2, the efficacy seemed to decrease after 1 week and 6 months respectively, but increasing the dosage led to another remission. CIPO in CTD is a severe condition that can evolve regardless of the underlying disease activity. Octreotide appears to be efficacious in improving both clinical symptoms and manometric patterns. When its therapeutic effect diminishes, increasing the dosage can be useful.

Chronic intestinal pseudo-obstruction in systemic lupus erythematosus.

BACKGROUND/AIMS: Chronic intestinal pseudo-obstruction (CIPO) reflects a dysfunction of the visceral smooth muscle or the enteric nervous system. Gastrointestinal manifestations are common in systemic lupus erythematosus (SLE) but CIPO has not been reported. Features of CIPO are reported in five patients with SLE. METHODS: From 1988 to 1993, five patients with SLE or SLE-like syndrome were hospitalised for gastrointestinal manometric studies. CIPO was the onset feature in two cases. Antroduodenal manometry (three hours fasting, two hours fed) was performed in all patients, and oesophageal manometry in four. RESULTS: Intestinal hypomotility associated with reduced bladder capacity and bilateral ureteral distension was found in four patients and aperistalsis of the oesophagus in three. Treatment, which consisted of high dose corticosteroids, parenteral nutrition, promotility agents, and antibiotics, led to remission of both CIPO and urinary abnormalities in all cases. Antroduodenal manometry performed in two patients after remission showed increased intestinal motility. One patient died, and postmortem examination showed intestinal vasculitis. CONCLUSIONS: CIPO in SLE is a life threatening situation that can be reversed by treatment. It may be: (a) a complication or onset feature of the disease; (b) secondary to smooth muscle involvement; (c) associated with ureteral and vesical involvement; (d) the result of intestinal vasculitis.

Biliary obstruction caused by portal cavernoma: a study of 8 cases.

BACKGROUND/AIMS: Biliary obstruction secondary to portal cavernoma is a rare and little-known entity. From 1985 to 1994, we observed eight cases of portal cavernoma compressing the biliary tract. We report here the features of biliary involvement in these cases of portal cavernoma including the circumstances of diagnosis, biliary tract morphology, liver pathology and the efficiency of various treatments. METHODS AND RESULTS: The causes of portal vein obstruction were portal vein thrombosis in one case, peritonitis in another, omphalitis in two cases, portal vein catheterization in one case and unknown in two cases. The portal cavernoma was revealed through esophageal varices ruptures in four patients. The mean time from portal cavernoma diagnosis to biliary involvement was 8 years (range 0-21). Six patients had acute cholangitis, one of whom revealed portal vein obstruction. All the patients had abnormal liver function tests. Imaging techniques (transparietal abdominal ultrasonography and abdominal computed tomography scan [n = 8], endosonography [n = 5] and endoscopic retrograde cholangiography [n = 7]) showed in all cases an extraluminal obstacle, laminating the common bile duct. Pathologic examination of the liver showed secondary biliary cirrhosis in one patient, periportal and perisinusoidal fibrosis in another and no abnormalities in three other cases. Three patients were treated by endoscopic sphincterotomy but cholangitis persisted in two cases, leading to death in one. One patient who underwent a splenorenal shunt was symptom-free 60 months after surgery. Balloon endoscopic dilatation of the common bile duct, performed in one case, led to normalization of liver biological tests. The patients with abnormal liver pathology were treated by propranolol and ursodesoxycholic acid. No complication had occurred after 6 and 24 months of follow-up. CONCLUSIONS: In conclusion, eliminating biliary obstruction seems to be essential in providing the best change of survival for patients when biliary obstruction becomes symptomatic. In cases of abnormal liver pathology, associating propranolol with ursodesoxycholic acid would seem to be useful.