Publications

Recently, there has been growing interest in understanding the ways in which lactation affects maternal health. The accompanying article by Palmer et al. (Am J Epidemiol. 2015;181(12):932-939), particularly their finding that prepregnancy obesity modifies the relationship between lactation and postpartum weight gain, makes an important contribution to this field. In this commentary, I discuss these findings within the context of other recent literature which indicates that whether or not a mother breastfeeds her newborn appears to be a powerful predictor of the mother's future risk of developing diabetes, hypertension, and cardiovascular disease, independent of maternal weight or body mass index in later life.

Thermogenic brown and beige adipocytes convert chemical energy to heat by metabolizing glucose and lipids. Serotonin (5-HT) neurons in the CNS are essential for thermoregulation and accordingly may control metabolic activity of thermogenic fat. To test this, we generated mice in which the human diphtheria toxin receptor (DTR) was selectively expressed in central 5-HT neurons. Treatment with diphtheria toxin (DT) eliminated 5-HT neurons and caused loss of thermoregulation, brown adipose tissue (BAT) steatosis, and a >50% decrease in uncoupling protein 1 (Ucp1) expression in BAT and inguinal white adipose tissue (WAT). In parallel, blood glucose increased 3.5-fold, free fatty acids 13.4-fold, and triglycerides 6.5-fold. Similar BAT and beige fat defects occurred in Lmx1b(f/f)ePet1(Cre) mice in which 5-HT neurons fail to develop in utero. We conclude 5-HT neurons play a major role in regulating glucose and lipid homeostasis, in part through recruitment and metabolic activation of brown and beige adipocytes.

Oligodendroglioma is one of the most common primary central nervous system neoplasms of dogs. It is often diagnosed in older, brachycephalic breeds, and although its typical clinical features and neuroanatomic location have been well described, less common presentations may hinder its diagnosis. We describe 3 cases of canine cerebral oligodendroglioma that clinically and grossly present as intraventricular tumors. Histologic findings in all cases were typical of oligodendroglioma. Neoplastic cells were uniformly immunoreactive for Olig2 and negative for neuron-specific enolase, neurofilament, and glial fibrillary acidic protein. In addition to the immunopositivity for Olig2, a cluster of morphologically distinct neoplastic cells in one of the cases was immunoreactive for synaptophysin, and the case was diagnosed as an oligodendroglioma with neurocytic differentiation. Based on these findings, oligodendroglioma should be included as a differential diagnosis for intraventricular neoplasia in dogs. Furthermore, oligodendroglioma with ventricular involvement should be differentiated from central neurocytoma by immunohistochemistry.