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.

Short communication: Mouse mammary tumor virus driven α-lactalbumin expression effects on lactation and fertility of transgenic mice

α-Lactalbumin (Alac) is one of the major milk proteins. Its gene expression is restricted to epithelial cells of the lactating mammary gland. The Alac interaction with a uridine 5'-diphosphate-galactosyltransferase induces lactose synthesis, a major osmotic regulator of milk secretion. Other functions attributed to this protein include induction of apoptosis and anti-inflammatory activities. To assess if forced expression of this gene during early gestation or involution could affect mammary physiology, an Alac-encoding minigene was expressed in transgenic mice under the transcriptional regulation of the mouse mammary tumor virus promoter. The mammary expression did not interfere with gestation, resulted in a slight increase in milk yield as indirectly assessed by the 11% increased growth rate of the pups reared by transgenic females compared with that of those reared by control mice, and induced a slight delay in the early involution process, as demonstrated by histological analyses. The use of the mouse mammary tumor virus promoter resulted in Alac expression in several nonmammary tissues, such as the brain, the testis, the ovary, and the uterus. Although it did not affect male reproductive performances, it induced a female subfertile phenotype, characterized by embryonic implantation failure in the transgenic female reproductive tract.

Eradication of rabbits (Oryctolagus cuniculus) by poisoning on three islands of the subantarctic Kerguelen Archipelago

In order to rehabilitate islands of the Kerguelen Archipelago degraded by the rabbit (Oryctolagus cuniculus), a program of eradication by poisoning was implemented from 1992 onwards on three islands: Verte Island (148 ha), Guillou Island (145 ha) and Cochons Island (165 ha). The poison used was a first-generation anticoagulant, chlorophacinone (0.05 g kg –1 ) on wheat bait treated to prevent germination. Bait was applied during the winter (July) in 1992 on Verte Island, in 1994 on Guillou Island and in 1997 on Cochons Island. Before poisoning, there were about 1250–1300 rabbits on Verte and Guillou Islands (9 rabbits per hectare) and 2600 rabbits on Cochons Island (16 rabbits per hectare). In total, about 1200, 1300 and 1600 kg of bait were distributed respectively on each island. Fifteen days after poisoning commenced 90% of the rabbits had died on Verte and Guillou Islands and 80% on Cochons Island. Two months later, only a small number of individuals survived; these were eliminated by shooting or poisoning, except on Cochons Island where a second bait application was necessary in the winter of 1999. No rabbits or tracks have been observed since 1994 on Verte Island, and since 1996 on Guillou Island, and the elimination of the last individuals is under way on Cochons Island. Inadvertent poisoning of non-target species by primary poisoning mainly involved two species of native birds (Larus dominicanus, Anas eatoni) and the mouse (Mus musculus) on Guillou and Cochons Islands. The cat (Feliss catus) on Guillou Island was the only species killed by secondary poisoning. The results are compared with other rabbit-eradication operations using a second-generation anticoagulant.