Volvulus at the i1eocaecal junction in germfree mice

Abstract

16 cases of intestinal volvulus were observed in a total of 200 inbred C57BL/6N, GR/N, and DBA/2N germfree mice during the course of 2 years. The volvulus was a twisting of the caecum at the junction of the ileum, caecum and colon, resulting in occlusion and death. In each case the caecum was greatly enlarged. During the same period no intestinal volvulus was seen in 5 other germfree strains or in F1 to F4 generations of identical strains of microflora-associated and conventionalized mice.

The effects of commensal microbiota on immune cell subsets and inflammatory responses

“…The high death rate observed in the early colonies of GF animals led to realization that commensal microorganisms in the intestine produce essential nutrients such as vitamins K and B. Supplementation of the diet with essential components extended the lifespan of GF animals to that of conventionally raised ones (2). Yet, sudden death due to cecal volvulus is not uncommon (4), and the average body weight and fat tissue volume tend to be smaller in some strains of GF animals compared to conventional animals (5). These observations suggest that although commensal microorganisms are not required for mammalian development, they provide essential nutrients and assist in digestion.…”

The Genetic Background Is Shaping Cecal Enlargement in the Absence of Intestinal Microbiota

“…However, a greatly enlarged cecum can cause health issues in aged GF animals. Cecal torsion due to a greatly enlarged cecum was described as the major health issue in aged GF animals [ 20 , 24 ]. Using two aging cohorts, we showed that the expected lifespan of GF B6J is shorter than that of GF C3H mice.…”

“…Furthermore, the cecal size in GF rodents increases with age [ 16 ]. Greatly increased cecum can promote cecal torsion causing obstruction of the digestive tract followed by the partial constriction of the blood supply and the death of the animal with or without previous clinical symptoms such as abdominal distension, lack of feces, ragged fur, hypoactivity, and ataxia [ 23 , 24 ].…”