Michael Lurie

Treatment with glutamine is associated with down-regulation of Toll-like receptor-4 and myeloid differentiation factor 88 expression and decrease in intestinal mucosal injury caused by lipopolysaccharide endotoxaemia in a rat

Recent evidence suggests that lipopolysaccharide (LPS) endotoxaemia in a rat causes significant mucosal injury. Our objective was to determine the effects of glutamine (Gln) on Toll‐like receptor 4 (TLR‐4), myeloid differentiation factor 88 (Myd88) and tumour necrosis factor (TNF)‐α receptor‐associated factor 6 (TRAF6) expression in intestinal mucosa following LPS endotoxaemia in a rat. For this purpose, male Sprague–Dawley rats were assigned randomly to one of three experimental groups of 10 rats each: (i) control rats underwent intraperitoneal (i.p.) injection of sterile saline once a day; (ii) rats were treated with LPS given i.p. once a day at a dose of 10 mg/kg for 48 h (two doses); and (iii) rats were pretreated with oral Gln given in drinking water (2%) 48 h before and following injection of LPS. Intestinal mucosal parameters, enterocyte proliferation and apoptosis were determined at death. TLR‐4 and MyD88 mRNA expression was measured with reverse transcription–polymerase chain reaction (RT–PCR). TLR‐4 and MyD88 protein expression were analysed by Western immunoblotting. We observed a statistically significant (P < 0·05) decrease in mucosal weight, mucosal DNA and enterocyte proliferation and a significant increase in enterocyte apoptosis in rat intestine, following LPS administration. These changes were attenuated significantly by dietary Gln. Expression of TLR‐4, MyD88 and TRAF6 mRNA in the mucosal ileum was significantly higher in LPS rats versus control rats (P = 0·0006, P = 0·0015, P = 0·03, respectively) as well as TLR‐4 and MyD88 protein expression. The administration of Gln reduced significantly the expression of TLR‐4, MyD88 and TRAF6 (P = 0·023, P = 0·014, P = 0·035, respectively) mRNA as well as TLR‐4 and MyD88 protein expression in ileum compared to LPS animals. We did not find a significant change in the expression of TLR‐4, MyD88 or TRAF6 in the jejunum of different groups. We conclude that treatment with Gln was associated with down‐regulation of TLR‐4, MyD88 and TRAF6 expression and concomitant decrease in intestinal mucosal injury caused by LPS endotoxaemia in a rat.

The effect of 100% oxygen on intestinal preservation and recovery following ischemia-reperfusion injury in rats.

Objective:Inhalation of oxygen improves the hemodynamic status and attenuates the inflammatory response after intestinal ischemia-reperfusion (IR). Yet, the use of hyperoxia is hindered by concerns that it could exacerbate reperfusion injury by increasing free radical formation. We examined the effect of hyperoxia on enterocyte turnover and intestinal preservation and rehabilitation following IR injury in rats. Design:Animal study. Setting:Research laboratory. Subjects:Male Sprague-Dawley rats. Interventions:Animals were assigned to four experimental groups: 1) Sham rats underwent laparotomy without vascular occlusion and breathed air, 2) Sham-oxygen rats underwent laparotomy without vascular occlusion and breathed 100% oxygen, 3) IR rats underwent occlusion of the superior mesenteric artery and portal vein for 30 minutes and breathed air, and 4) IR group treated with oxygen (IR-O2)rats underwent IR and breathed 100% oxygen starting 10 minutes before and continued for the first 6 hours after reperfusion. Intestinal structural changes, enterocyte proliferation, and enterocyte apoptosis were determined 24 hours after IR. Measurements and Main Results:In IR rats, breathing 100% oxygen resulted in a significant decrease in Parks injury score in the ileum (p < 0.05 from untreated IR rats). Rats treated with oxygen also demonstrated a significant increase in mucosal weight (p < 0.05) and mucosal DNA (p < 0.05) in the jejunum and ileum, and an increase in villus height (p < 0.01), and crypt depth (p < 0.05) in the ileum. Enterocyte proliferation (assessed by bromodeoxyuridine uptake) was significantly decreased in the jejunum and ileum in untreated IR rats. Oxygen therapy increased enterocyte proliferation in the ileum, and diminished both the apoptosis index and Bax gene expression in the jejunum and ileum (p < 0.05). Plasma thermochemiluminescence oxidizability assay revealed significantly higher thermochemiluminescence ratios in IR group treated with oxygen than in untreated IR rats (p < 0.05) at 6 hours postreperfusion suggesting a significantly lower prior in vivo molecular oxidation. Conclusions:Hyperoxia reduces small bowel injury, accelerates enterocyte turnover, and improves intestinal rehabilitation after IR.

Effect of Oral Glutamine on Enterocyte Turnover during Methotrexate-Induced Mucositis in Rats

Background/Aims: The objective of this study was to evaluate the effects of oral glutamine in preventing intestinal mucosal damage caused by methotrexate (MTX) in rats. Methods: Male Sprague-Dawley rats were divided into 3 experimental groups: control rats, rats treated intraperitoneally with MTX (MTX rats) and rats treated with oral glutamine in the drinking water (2%) 72 h following intraperitoneal injection of a single dose of MTX (MTX-glutamine rats). Intestinal mucosal damage (Park’s injury score), mucosal structural changes, enterocyte proliferation and enterocyte apoptosis were determined 72 h following MTX injection. RT-PCR was used to determine Bax and Bcl-2 mRNA expression. Results: MTX-glutamine rats demonstrated greater jejunal and ileal mucosal weight and mucosal DNA, greater ileal villus height and crypt depth, and a greater index of proliferation in the jejunum and ileum compared to MTX animals. A significant decrease in enterocyte apoptosis in the ileum of MTX-glutamine rats (vs. MTX) was accompanied by decreased Bax and increased Bcl-2 mRNA expression. Conclusions: Treatment with oral glutamine prevents mucosal injury and improves intestinal recovery following MTX injury in the rat.

Involvement of the bax and bcl-2 system in the induction of germ cell apoptosis is correlated with the time of reperfusion after testicular ischemia in a rat model.

The objective of this study was to examine the relationship between time of reperfusion and bax/bcl-2-dependent germ cell apoptosis after testicular ischemia-reperfusion injury in the rat. In ischemic testis, bax/bcl-2 ratio did not change significantly, and the elevation of germ cell apoptosis was not marked; in the contralateral testis, germ cell apoptosis increased after 6 hours of reperfusion, achieved statistical significance after 24 hours, and decreased after 72 hours of reperfusion and was initiated by decreased bcl-2 messenger RNA levels and elevated bax/bcl-2 ratio within the first 6 hours of reperfusion.

Leptin accelerates enterocyte turnover during methotrexate-induced intestinal mucositis in a rat

Gastrointestinal mucositis occurs as a consequence of cytotoxic treatment. In the present study, we tested whether leptin can protect gut epithelial cells from methotrexate (MTX)-induced intestinal damage. Non-pretreated and pretreated with MTX Caco-2 cells were incubated with increasing concentrations of leptin for 24 hours. Cell proliferation and apoptosis were assessed using FACS analysis. Adult rats were divided into three experimental groups: Control rats; MTX-rats were treated with a single dose of MTX, and MTX- LEP rats were also treated with leptin for 3 days. Intestinal mucosal damage (Parks score), mucosal structural changes (bowel and mucosal weight, mucosal DNA and protein content, villus height and crypt depth), enterocyte proliferation, and enterocyte apoptosis were measured at sacrifice. RT-PCR was used to determine the level of bax and bcl-2 mRNA expression. In the vitro experiment, treatment with leptin of Caco-2 cells pre-treated with MTX resulted in a significant stimulation of cell proliferation and inhibition of cell apoptosis in a dose-dependent manner. In the vivo experiment, MTX-LEP rats demonstrated a greater jejunal and ileal bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, as well as a greater enterocyte proliferation index compared to MTX-animals. MTX-LEP rats also showed a trend toward an increase in enterocyte apoptosis that was accompanied by an increase in bax mRNA and decrease in bcl-2 mRNA expression. In conclusion, leptin enhances proliferation and decreases apoptosis in Caco-2 cells pretreated with MTX. In a rat model of MTX-induced mucositis, treatment with leptin improves intestinal recovery and enhances enterocyte turnover.

Effect of lactulose on bacterial translocation and intestinal adaptation in a rat model of short bowel syndrome.

Background: It is frequently assumed that dietary nondigestible carbohydrates improve host resistance to intestinal infections by stimulating proliferation of the protective gut microflora. Therefore, the aim of this study was to define the effect of lactulose, a nondigestible carbohydrate, on bacterial translocation and intestinal adaptation in a rat model of short bowel syndrome (SBS). Materials and Methods: Male Sprague-Dawley rats were divided into 3 experimental groups. Sham rats underwent bowel transection, SBS rats underwent 75% small bowel resection, and SBS-LAC rats underwent bowel resection and were treated with oral lactulose given in drinking water at a dose of 1.5 g · kg−1 · day−1 from the 3rd to the 15th postoperative day. Bacterial translocation (to mesenteric lymph nodes, liver, and portal and peripheral blood) and parameters of intestinal adaptation were determined on day 15. Results: Treatment with lactulose did not change bacterial translocation, but decreased ileal mucosal weight (20%; P < 0.05), ileal mucosal DNA (2-fold decrease; P < 0.05) and protein (26%; P < 0.05), villus height in jejunum (21%; P < 0.05) and crypt depth in ileum (17%; P < 0.05), proliferation rates in jejunum (18%; P < 0.05) and ileum (15%; P < 0.05), and apoptotic index in jejunum (40%; P < 0.05) and ileum (36%; P < 0.05) compared with SBS animals. Bax expression was upregulated in SBS rats compared with control animals, but decreased following treatment with lactulose. Conclusions: In a rat model of SBS, oral lactulose does not improve bacterial translocation from the intestine, but inhibits intestinal adaptation.

Wilms' tumor gene 1: a possible new proangiogenic factor in Hodgkin lymphoma.

Introduction:Wilms’ tumor gene 1 (WT1) was recently found to play a role in solid and hematologic malignancies and serves as a marker of prognosis and minimal residual disease in acute leukemia. WT1 was also found to be involved in tumor angiogenesis. There are no data concerning the involvement of WT1 in angiogenesis in lymphoproliferative tumors. The aim of this study was to explore the involvement of WT1 in Hodgkin lymphoma. Methods:The expression of WT1, neuropilin 1, and VEGF was tested by immunohistochemistry in lymph nodes biopsies of 20 Hodgkin patients and 7 reactive lymph nodes. Results:WT1 was expressed in endothelial cells, in 95% of the malignant lymph nodes. The average of WT1 expression scale was higher in the malignant lymph nodes than in reactive lymph nodes. We found a positive correlation between WT1 expression scale and the angiogenesis scale (0.53) that was statistically significant (P<0.05). As the number of vessels increases, the expression of WT1 is more intense. Conclusions:We found, for the first time, that WT1 is expressed in endothelial cells in Hodgkin lymphoma. The clinical implications of these findings should be tested in a future study.

Gottron’s papules-like eruption developing under hydroxyurea therapy

A 57-year-old white female developed a Gottron’s papules (GP)-like eruption, without any of the other clinical or laboratory signs of dermatomyositis (DM). She was under hydroxyurea treatment for chronic myeloid leukemia at the time. Skin biopsy was compatible with seborrheic keratosis. Conditions presenting with GP but unrelated to DM are reviewed, with emphasis on hydroxyurea-induced skin lesions.

Metastatic small cell carcinoma presenting as acute hepatic failure

was suspected that these maneuvers would be of limited and only transient benefit, as they would have no effect on the underlying neurological condition that had precipitated and was leading to continued colon pseudo-obstruction. After the second daily infusion of i.v. immunoglobulin, spontaneous defecation and passage of flatus ensued and abdominal distention promptly resolved. Three days after i.v. immunoglobulin therapy began, flank paresthesias and GI symptoms had completely resolved, and there was subtle subjective improvement in the patient’s facial nerve palsy. He was discharged uneventfully, and was seen 1 month later. At this time, his bowel habits remained normal, the paresthesias over the flank regions had not returned, and paresthesias in the feet had resolved. Facial weakness persisted, but was improved. Motor strength in the extremities was normal and vibratory sensation had improved. Deep tendon reflexes were present, although diminished in the patellar and Achilles tendons. Autonomic dysfunction is a common accompaniment in severe GBS. A recent large retrospective study documented adynamic ileus in 15% of 114 patients (1). The retrospective design of this study may have contributed to an underestimation of the frequency of this problem in patients afflicted with GBS. The pathophysiology of ileus/colon pseudo-obstruction in GBS remains unclear, but likely occurs as a result of immune-mediated autonomic dysfunction and/or prolonged immobilization. Each of these factors may contribute to a varying degree in a given case, depending upon the stage and severity of the illness. Our patient presented with an atypical GBS variant. Although CSF examination in patients with GBS usually shows an elevation of the protein level without a pleocytosis (albuminocytological dissociation), CSF pleocytosis is now known to occur in up to 20% of cases, as in our patient (2). This unusal case is a reminder that seemingly unrelated neurological symptoms may occur in patients with colon pseudo-obstruction, and their recognition may lead to the diagnosis of a generalized neurological disorder. Although immunoglobulin (or plasmapheresis) therapy is ordinarily reserved for moderate to severely symptomatic GBS, this anecdotal report supports the use of such treatment for symptoms of severe colon pseudo-obstruction that fail to improve with the institution of conservative measures.