Although wasting marmoset syndrome (WMS) is one of the biggest problems facing captive marmoset colonies, the mechanisms underlying its pathogenesis remain unclear. In our clinical experience, it is difficult to cure WMS-affected marmosets with severe
hypoalbuminemia. Thus, the mechanisms underlying
hypoalbuminemia in WMS must be understood. In the present study, we investigated whether intestinal
protein loss, a known reason for
hypoalbuminemia, occurs in this disease. Fecal α1-proteinase inhibitor (α1-PI, also known as α1-antitrypsin) has been used to diagnose intestinal
protein loss in other species. To develop an assay system for this
protein, marmoset α1-PI was purified from plasma and
antibodies against it were developed using the purified
protein. Using the
antibodies, a sandwich
enzyme-linked
immunosorbent assay (ELISA) to measure marmoset α1-PI was developed, and its detection sensitivity for fecal samples was ∼20-fold higher than that of a commercial kit for human α1-PI. From this ELISA, the reference intervals for serum and feces of healthy marmosets were 0.87-1.85 mg/ml and 0.53-395.58 μg/g, respectively. The average concentrations of α1-PI in serum and feces of seven WMS-affected marmosets were 1.17 mg/ml and 1357.58 μg/g, respectively. Although there were no significant differences in the serum concentrations between healthy and WMS-affected marmosets, the fecal concentrations were significantly higher in WMS-affected marmosets than in healthy individuals, suggesting that intestinal
protein loss occurs in WMS. Intestinal
protein loss of WMS-affected marmosets was significantly attenuated with treatment, suggesting that it is one of the mechanisms involved in the
hypoalbuminemia observed in WMS.