Intranasal insulin reverts central pathology and cognitive impairment in diabetic mother offspring

Adverse effects in diabetic mothers offspring (DMO) are a major concern of increasing incidence. Among these, chronic central complications in DMO remain poorly understood, and in extreme cases, diabetes can essentially function as a gestational brain insult. Nevertheless, therapeutic alternatives for DMO are limited.

Therefore, we have analyzed the central long-term complications in the offspring from CD1 diabetic mothers treated with streptozotozin, as well as the possible reversion of these alterations by insulin administration to neonates. Brain atrophy, neuronal morphology, tau phosphorylation, proliferation and neurogenesis were assessed in the short term (P7) and in the early adulthood (10 weeks) and cognitive function was also analyzed in the long-term.

Central complications in DMO were still detected in the adulthood, including cortical and hippocampal thinning due to synaptic loss and neuronal simplification, increased tau hyperphosphorylation, and diminished cell proliferation and neurogenesis. Additionally, maternal diabetes increased the long-term susceptibility to spontaneous central bleeding, inflammation and cognition impairment in the offspring. On the other hand, intracerebroventricular insulin administration to neonates significantly reduced observed alterations. Moreover, non-invasive intranasal insulin reversed central atrophy and tau hyperphosphorylation, and rescued central proliferation and neurogenesis. Vascular damage, inflammation and cognitive alterations were also comparable to their counterparts born to nondiabetic mice, supporting the utility of this pathway to access the central nervous system.

Our data underlie the long-term effects of central complications in DMO. Moreover, observed improvement after insulin treatment opens the door to therapeutic alternatives for children who are exposed to poorly controlled gestational diabetes, and who may benefit from more individualized treatments.