Glomerulopathy in spontaneously obese rhesus monkeys with type 2 diabetes: a stereological study

A spontaneous hyperglycaemic cynomolgus monkey presents cognitive deficits, neurological dysfunction and cataract

Chronic hyperglycaemia is a chief feature of diabetes mellitus and complicates with many systematic anomalies. Non-human primates (NHPs) are excellent for studying hyperglycaemia or diabetes and associated comorbidities, but lack behavioural observation. In the study, behavioural, brain imaging and histological analysis were performed in a case of spontaneously hyperglycaemic (HGM) Macaca fascicularis. The results were shown that the HGM monkey had persistent body weight loss, long-term hyperglycaemia, insulin resistance, dyslipidemia, but normal concentrations of insulin, C-peptide, insulin autoantibody, islet cell antibody and glutamic acid decarboxylase antibody. Importantly, an impaired working memory in a delayed response task and neurological dysfunctions were found in the HGM monkey. The tendency for atrophy in hippocampus was observed by magnetic resonance imaging. Lenticular opacification, lens fibres disruptions and vacuole formation also occurred to the HGM monkey. The data suggested that the spontaneous HGM monkey might present diabetes-like characteristics and associated neurobehavioral anomalies in this case. This study first reported cognitive deficits in a spontaneous hyperglycaemia NHPs, which might provide evidence to use macaque as a promising model for translational research in diabetes and neurological complications.

Transplantation of bone marrow mesenchymal stem cells for the treatment of type 2 diabetes in a macaque model

Bone marrow mesenchymal stem cells (BMSCs) are self-renewing, multipotent cells that can migrate to pathological sites and thereby provide a new treatment in diabetic animals. Superparamagnetic iron oxide/4',6-diamidino-2-phenylindole (DAPI) double-labeled BMSCs were transplanted into the pancreatic artery of macaques to treat type 2 diabetes mellitus (T2DM). The treatment efficiency of BMSCs was also evaluated. After successful induction of the T2DM model, the treatment group received double-labeled BMSCs via the pancreatic artery. Six weeks after BMSC transplantation, the fasting blood glucose and blood lipid levels measured in the treatment group were significantly lower (p < 0.05) than in the model group, although they were not reduced to normal levels (p < 0.05). Additionally, the serum C-peptide levels were significantly increased (p < 0.05). An intravenous glucose tolerance test and C-peptide release test had significant changes to the area under the curve. Within 14 days of the transplantation of labeled cells, the pancreatic and kidney tissue of the treatment group emitted a negative signal that was visible on magnetic resonance imaging (MRI). Six weeks after transplantation, DAPI signals appeared in the pancreatic and kidney tissue, which indicates that the BMSCs were mainly distributed in damaged tissue. Labeled stem cells can be used to track migration and distribution in vivo by MRI. In conclusion, the transplantation of BMSCs for the treatment of T2DM is safe and effective.

Investigation and treatment of type 2 diabetes in nonhuman primates

Nonhuman primates provide the ideal animal model for discovering and examining further the mechanisms underlying human type 2 diabetes mellitus. In all aspects studied to date the nonhuman primate has been shown to develop the same disease with the same features that develop in overweight middle-aged humans. This includes the progressive development of the known complications of diabetes, all of which are extraordinarily like those identified in humans. In addition, for the development and evaluation of new therapeutic agents, the translation of findings from nonhuman primates to application in humans has been highly predictable. Both therapeutic efficacy and identification of potential adverse responses can be effectively examined in nonhuman primates due to their great similarity to humans at the molecular, biochemical, and physiological levels. This chapter provides guidance for the development and management of a colony of monkeys with naturally occurring type 2 diabetes mellitus.