Qi Yu

Atherosclerosis constitutes a pathological process underlying cardiovascular diseases. There is growing evidence that IGFBP5 is a causative factor, although the conclusions of different studies are inconsistent. The present study aims to confirm the role and mechanism of IGFBP5 in atherosclerosis. The expression of IGFBP5 was induced in the skeletal muscle of male ApoE^−/− mice, an atherosclerosis model, using adeno-associated virus, resulting in elevated circulating IGFBP5 levels. Changes in blood lipids were detected, and pathological changes in the aorta were observed. Analysis of IGFBP5 function using RNA sequencing and validation were performed in a mouse aortic smooth muscle cell line. The results demonstrated that IGFBP5 overexpression exacerbated the development of aortic lesions in this murine models without any discernible alterations in lipid profile parameters; the arterial transcriptomic landscape revealed that heightened IGFBP5 levels predominantly influenced pathways governing smooth muscle cell proliferation and motility. In vitro experimentation corroborated these findings, showcasing the stimulatory effect of IGFBP5 on VSMC (vascular smooth muscle cell) proliferation and migration, provoking a transition toward a proliferative phenotype. IGFBP5 promotes atherosclerosis in ApoE^−/− mice through the phenotypic transformation of VSMCs. This finding suggests that IGFBP5 has the potential to serve as an indicator of atherosclerosis diagnosis and a target for therapeutic interventions in the future.

Statins are widely used to treat hyperlipidemia and atherosclerotic cardiovascular diseases (ACVD) by significantly lowering low-density lipoprotein cholesterol (LDL-C) levels. However, their use has been associated with an increased risk of type 2 diabetes (T2D), a paradox given their lipid-lowering benefits. This study investigates the role of LDL receptors (LDLR) and proprotein convertase subtilisin/kexin type 9 (PCSK9) in the diabetogenic effects of atorvastatin on pancreatic β-cells. Using the MIN6 pancreatic β-cell line, we assessed the impact of atorvastatin on LDL-C uptake, PCSK9 expression, glucose-stimulated insulin release (GSIR), and cell proliferation. Cellular cholesterol assays, EdU labeling, Dil-LDL uptake, western blot analysis, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and ELISA, were employed to measure relevant biomarkers and cellular responses. Male C57BL/6j mice were treated with atorvastatin to validate in vitro findings. Atorvastatin enhances LDL-C uptake by upregulating LDLR on the cell surface, without causing excess cholesterol accumulation. Additionally, atorvastatin suppresses PCSK9 expression, which is crucial for LDLR degradation. Interestingly, atorvastatin, combined with exogenous LDL-C, impairs glucose-stimulated insulin release (GSIR) but promotes cell proliferation, highlighting a potential mechanism for statin-associated diabetes. Oral administration of atorvastatin in mice reduced plasma PCSK9 and insulin levels, supporting the in vitro findings. These results indicate that while atorvastatin effectively lowers circulating cholesterol, it may adversely affect pancreatic β-cell function by modulating LDLR and LDL-C uptake, thereby increasing the risk of T2D. This study highlights the importance of further research to develop strategies mitigating the diabetogenic effects of statins while maintaining their cardiovascular benefits.

There has been interest in the connection between cardiovascular diseases and osteoporosis, both of which share hyperlipidemia as a common pathological basis. Osteoporosis is a progressive metabolic bone disease characterized by reduced bone mass, deteriorated bone microstructure, increased bone fragility and heightened risk of bone fractures. Dysfunction of osteoblastic cells, vital for bone formation, is induced by excessive internalization of lipids under hyperlipidemic conditions, forming the crux of hyperlipidemia‑associated osteoporosis. Autophagy, a process fundamental to cell self‑regulation, serves a critical role in osteoblastic cell function and bone formation. When activated by lipids, lipophagy inhibits osteoblastic cell differentiation in response to elevated lipid concentrations, resulting in reduced bone mass and osteoporosis. However, an in‑depth understanding of the precise roles and mechanisms of lipophagy in the regulation of osteoblastic cell function is required. Study of the molecular mechanisms governing osteoblastic cell response to excessive lipids can result in a clearer understanding of osteoporosis; therefore, potential strategies for preventing hyperlipidemia‑induced osteoporosis can be developed. The present review discusses recent progress in elucidating the molecular mechanisms of lipophagy in the regulation of osteoblastic cell function, offering insights into hyperlipidemia‑induced osteoporosis.