Some studies have shown that gut microbiota along with its metabolites is closely associated with diabetic mellitus (DM). In this study we explored the relationship between gut microbiota and kidney injuries of early diabetic nephropathy (DN) and its underlying mechanisms. Male SD rats were intraperitoneally injected with streptozotocin to induce DM. DM rats were orally administered compound broad-spectrum antibiotics for 8 weeks. After the rats were sacrificed, their blood, urine, feces, and renal tissues were harvested for analyses. We found that compared with the control rats, DM rats had abnormal intestinal microflora, increased plasma acetate levels, increased proteinuria, thickened glomerular basement membrane, and podocyte foot process effacement in the kidneys. Furthermore, the protein levels of angiotensin II, angiotensin-converting enzyme, and angiotensin II type 1 receptor in the kidneys of DM rats were significantly increased. Administration of broad-spectrum antibiotics in DM rats not only completely killed most intestinal microflora, but also significantly lowered the plasma acetate levels, inhibited intrarenal RAS activation, and attenuated kidney damage. Finally, we showed that plasma acetate levels were positively correlated with intrarenal angiotensin II protein expression (
r
= 0.969,
P
< 0.001). In conclusion, excessive acetate produced by disturbed gut microbiota might be involved in the kidney injuries of early DN through activating intrarenal RAS.
Eleven new metabolites, including nine lovastatin analogues [oblongolides N-V (1-2 and 5-11), which were defined as naphthalene-type fungal polyketides], one linear furanopolyketide (13) and a monoterpene named dihydroxysabinane (14), together with four known compounds including oblongolides B (3) and C (4), one linear furanopolyketide (12) and the sesterterpene terpestacin (15), were isolated from the endophytic fungal strain Phomopsis sp. XZ-26 of Camptotheca acuminate. Their structures were elucidated by spec-
Finding new therapeutic targets of glomerulosclerosis treatment is an ongoing quest. Due to a living environment of various stresses and pathological stimuli, podocytes are prone to injuries; moreover, as a cell without proliferative potential, loss of podocytes is vital in the pathogenesis of glomerulosclerosis. Thus, sufficient understanding of factors and underlying mechanisms of podocyte injury facilitates the advancement of treating and prevention of glomerulosclerosis. The clinical symptom of podocyte injury is proteinuria, sometimes with loss of kidney functions progressing to glomerulosclerosis. Injury-induced changes in podocyte physiology and function are actually not a simple passive process, but a complex interaction of proteins that comprise the anatomical structure of podocytes at molecular levels. This chapter lists several aspects of podocyte injuries along with potential mechanisms, including glucose and lipid metabolism disorder, hypertension, RAS activation, micro-inflammation, immune disorder, and other factors. These aspects are not technically separated items, but intertwined with each other in the pathogenesis of podocyte injuries.
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