Microbiology and Biotechnology Research: An Overview Vol. 6

Vitamin D is crucial for life in higher-living organisms. It is a sterol prohormone with no intrinsic biological activity. Calcitriol, the active form of vitamin D, is synthesised in the kidneys. It has well-known pleiotropic and cytoprotective properties. In addition to regulating parathyroid hormone secretion and enhancing gut calcium absorption, it exhibits antioxidant, anti-inflammatory, antiproliferative, and antineoplastic effects. Acute Kidney Injury (AKI) is a common clinical syndrome that significantly affects kidney function and can lead to an elevated risk of morbidity and mortality. Unlike Chronic Kidney Disease, the role of vitamin D in AKI is not fully understood. Thus, this review aimed to understand how dysregulated vitamin D homeostasis occurs in AKI, as well as to explore how vitamin D deficiency and excess influence AKI. A comprehensive literature search was conducted between January 2000 and June 2024 to uncover relevant works detailing vitamin D homeostasis in health, as well as investigating the impact of vitamin D deficiency and excess in humans, animals, and in vitro cell models of AKI. According to the findings of this review, vitamin D appears to have a reciprocal relationship with AKI. Acute renal injury, among other factors, can cause hypo- or hypervitaminosis D. Conversely, AKI can also be caused by vitamin D deficiency and toxicity. Severe deficiency has been associated with the increased incidence and poor prognosis of AKI in critically ill patients, whereas excessive dosing of vitamin D has been shown to precipitate AKI in clinical case series. Even though hypovitaminosis D is associated with AKI, it is uncertain how it impacts AKI outcomes in distinct clinical scenarios. Newer therapeutic options might emerge as a result of understanding these challenges. Vitamin D supplementation may ameliorate renal injury but needs further validation. Furthermore, hypervitaminosis D has also been implicated in AKI by causing hypercalcemia and hyperphosphatemia. It is crucial to avoid prolonged, uncontrolled, and unsupervised supraphysiological vitamin D administration, especially intramuscular injection. Future studies through larger clinical trials, the integration of diverse patient cohorts, and the systematic evaluation of confounding factors such as comorbidities (e.g., diabetes, cardiovascular disease), concurrent medications, and ICU interventions on AKI outcomes and vitamin D metabolism are essential to clarify the therapeutic role of vitamin D in AKI management.