Oral Supplementation with the Polyamine Spermidine Affects Hepatic but Not Pulmonary Lipid Metabolism in Lean but Not Obese Mice.

The polyamine spermidine is discussed as a caloric restriction mimetic and therapeutic option for obesity and related comorbidities. This study tested oral spermidine supplementation with regard to the systemic, hepatic and pulmonary lipid metabolism under different diet conditions. Male C57BL/6 mice were fed a purified control (CD), high sucrose (HSD) or high fat (HFD) diet with (-S) or without spermidine for 30 weeks. In CD-fed mice, spermidine decreased body and adipose tissue weights and reduced hepatic lipid content. The HSD induced hepatic lipid synthesis and accumulation and hypercholesterolemia. This was not affected by spermidine supplementation, but body weight and blood glucose were lower in HSD-S compared to HSD. HFD-fed mice showed higher body and fat depot weights, prediabetes, hypercholesterolemia and severe liver steatosis, which were not altered by spermidine. Within the liver, spermidine diminished hepatic expression of lipogenic transcription factors SREBF1 and 2 under HSD and HFD and affected the expression of other lipid-related enzymes. In contrast, diet and spermidine exerted only minor effects on pulmonary parameters. Thus, oral spermidine supplementation affects lipid metabolism in a diet-dependent manner, with significant reductions in body fat and weight under physiological nutrition and positive effects on weight and blood glucose under high sucrose intake, but no impact on dietary fat-related parameters.

Microglia response in retina and optic nerve in chronic experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is a common rodent model for multiple sclerosis (MS). Yet, the long-term consequences for retina and optic nerve (ON) are unknown. C57BL/6 mice were immunized with an encephalitogenic peptide (MOG35-55) and the controls received the carriers or PBS. Clinical symptoms started at day 8, peaked at day 14, and were prevalent until day 60. They correlated with infiltration and demyelination of the ON. In MOG-immunized animals more microglia cells in the ONs and retinas were detected at day 60. Additionally, retinal ganglion cell (RGC) loss was combined with an increased macroglia response. At this late stage, an increased number of microglia was associated with axonal damage in the ON and in the retina with RGC loss. Whether glial activation contributes to repair mechanisms or adversely affects the number of RGCs is currently unclear.

Analysis of fetal and maternal microvasculature in ruminant placentomes by corrosion casting.

Vascular corrosion casting is a useful tool for studying the vascular architecture of complex organs. The synepitheliochorial placenta of ruminants is composed of two closed blood circuits, a fetal and a maternal one. The microvasculature of each circuit has the shape of the corresponding cotyledon (villous trees) and caruncle (crypts). These two compartments interdigitate with each other in a complementary fashion. Understanding three-dimensional vascular arrangements is facilitated by scanning electron microscopy of vascular corrosion casts. Methods to be used in the generation of vascular casts from fetal and maternal placentomal blood vessels are described, with special emphasis on casting resins and corrosion using potassium hydroxide. The procedure of splitting larger casts following gelatin embedding and freezing is also presented.