Fig. 4: Ketogenic diet suppresses angiogenesis and macrophage activation.

A, B. HE stained pancreatic sections of 45-week-old Men1^f/f-RipCre⁺ mice fed a normal diet (N = 3) or Men1^f/f-RipCre⁺ mice fed a ketogenic diet from 11 weeks of age (N = 3) were analyzed. Typical vascularized islets from the mice fed a normal diet, and non-vascularized islets from the mice fed a ketogenic diet are shown (A). The number of vessels with an area of 0.0006 mm² or greater was calculated from 4 fields derived from 4 islets from each mouse. In B, the numbers of vessels are counted and shown as a graph, and data are represented as the mean ± SD. C–G. Islets were isolated from 45-week-old Men1^f/f-RipCre⁺ mice fed a normal diet or Men1^f/f-RipCre⁺ mice fed a ketogenic diet from 10 weeks of age. Three sets of islets were isolated from the mice fed a normal diet (N = 2, 2, 3) or mice fed a ketogenic diet from 10 weeks of age (N = 2, 3, 7). mRNAs were purified from islets, and the expression of genes involved in angiogenesis (Mmp2 and Mmp9) (C, D) and macrophage activation (Nos2 and Il1β) (E, F) were analyzed. An endocrine marker, Synaptophysin, was also analyzed to evaluate the consistency of islet isolation (G). The relative gene expression levels within each set of samples obtained from mice on the normal diet and those on the ketogenic diet were calculated. The data from islets fed a normal diet were consistently assigned a value of 1, hence the absence of error bars. Data from islets fed a ketogenic diet are represented as the mean fold expression ± SD.