Khailova L, Dvorak K, Arganbright KM, Halpern MD, Kinouchi T, Yajima M, Dvorak B. Bifidobacterium bifidum improves intestinal integrity in a rat model of necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is a devastating intestinal disease of neonates, and clinical studies suggest the beneficial effect of probiotics in NEC prevention. Recently, we have shown that administration of Bifidobacterium bifidum protects against NEC in a rat model. Intestinal apoptosis can be suppressed by activation of cyclooxygenase-2 (COX-2) and increased production of prostaglandin E2 (PGE2). The present study investigates the effect of B. bifidum on intestinal apoptosis in the rat NEC model and in an intestinal epithelial cell line (IEC-6), as a mechanism of protection against mucosal injury. Premature rats were divided into the following three groups: dam fed, hand fed with formula (NEC), or hand fed with formula supplemented with B. bifidum (NEC + B. bifidum ). Intestinal Toll-like receptor-2 (TLR-2), COX-2, PGE2, and apoptotic regulators were measured. The effect of B. bifidum was verified in IEC-6 cells using a model of cytokine-induced apoptosis. Administration of B. bifidum increased expression of TLR-2, COX-2, and PGE2 and significantly reduced apoptosis in the intestinal epithelium of both in vivo and in vitro models. The Bax-to-Bcl-w ratio was shifted toward cell survival, and the number of cleaved caspase-3 positive cells was markedly decreased in B. bifidum -treated rats. Experiments in IEC-6 cells showed anti-apoptotic effect of B. bifidum . Inhibition of COX-2 signaling blocked the protective effect of B. bifidum treatment in both in vivo and in vitro models. In conclusion, oral administration of B. bifidum activates TLR-2 in the intestinal epithelium. B. bifidum increases expression of COX-2, which leads to higher production of PGE2 in the ileum and protects against intestinal apoptosis associated with NEC. This study indicates the ability of B. bifidum to downregulate apoptosis in the rat NEC model and in IEC-6 cells by a COX-2-dependent matter and suggests a molecular mechanism by which this probiotic reduces mucosal injury and preserves intestinal integrity.

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The development of pancreatic amylase activity was examined in rats fed in regular cages or in special cages, designed so the pups could not reach solid food to prevent weaning. In both groups, the amylase activity in zymogen granules increased in rat pups aged 14 days, peaked at 18 days, and thereafter remained at a 1.6-fold higher level than at 14 days of age. An increase in the plasma concentration of immunoreactive insulin preceded the increase of amylase activity, whereas the plasma concentration of C-peptide, indicating the secretion rate of endogenous insulin, remained unchanged. The administration of insulin at 20 ng/ml (the physiological concentration) in the milk formula caused an increase in the plasma insulin concentration of 17-day-old pups. In addition, increased pancreatic amylase activity was observed in 17-day-old rats raised on milk formula to which insulin was added. We propose that the increase of amylase activity at the beginning of weaning is dependent on the milk-borne insulin and not on the dietary change in rats.

A B S T R A C T Kinetics of 5a-androstane-3a, 17p-diol (3a-diol) were studied in man. Clearance than expected from information on in vitro binding in plasma. The kinetic data is of interest since 3a-diol has a calculated inner pool (Vi) volume of 12-14 liters, similar to 1713-hydroxyandrost-4-en-3-one (testosterone) and 5a-androstan-1713-ol-3-one (dihydrotestosterone), but the calculated outer pool (V2) of 33.5 liters is very large as are the metabolic rate and transfer constants. In contrast to testosterone and dihydrotestosterone, 3a-diol, although bound to sex hormone binding globulin, has a high metabolic clearance of which a large fraction represents extrahepatic (splanchnic) metabolism. A production rate of 3a-diol similar to dihydrotestosterone together with rather unique kinetic characteristics encourages further investigation of the biological role of this potent androgen.