Association of serums HIF-1α and HIF-2α with the levels and severity of renal fibrosis: a retrospective cohort study

Renal fibrosis is a key pathological feature in the progression of chronic kidney disease (CKD). Hypoxia is one of the critical factors and plays a role in the development of renal fibrosis. We aim to investigate the relationship between hypoxia-induced factors (HIF-1α and HIF-2α) and the levels and severity of renal fibrosis, and changes in their levels in the CKD population. We conducted a single-center, retrospective cohort study, that included (n = 204) CKD participants. Participants who were complicated with renal fibrosis were assigned according to the degree of the disease to mild group (n = 61), moderate group (n = 47), and severe group (n = 26). Additionally, (n = 70) healthy participants with normal kidney function were enrolled in the control group. Data and laboratory findings were collected between October 2023 and February 2024. HIF-1α expression levels increased significantly with the progression of renal fibrosis, the severe group exhibited significantly higher HIF-1α levels compared to the mild group (P < 0.001), moderate group (P < 0.05), and control group (P < 0.001), showing a mild positive correlation coefficient (R = 0.271, 95%CI [0.45–0.49], P < 0.001). HIF-2α, expression levels in the severe group were significantly elevated versus the mild group (P < 0.01), moderate group (P < 0.01), and normal controls (P < 0.001), indicating more pronounced changes during mid-to-late stage fibrosis with a stronger positive correlation coefficient (R = 0.970, 95%CI [0.35–0.38], P < 0.001). Our findings offer clinical insights into the molecular mechanisms of HIF in renal fibrosis and offer evidence for determining the optimal timing of HIF-related pathways.that to be evaluated for their potential to influence progression in prospective studies.