**Acknowledgements**

of vitamin D in AKI is not as well defined. It is reasonable to hypothesize that the predisposition of vitamin D-deficient critically ill patients to AKI is related to the innate and adaptive immune

Vitamin D is a critical substance for bone and mineral regulation and is also a hormone with pleiotropic functions. Vitamin D exerts beneficial effects on immunomodulatory effects, alleviates metabolic syndrome, improves insulin resistance, maintains regular blood pressure, increases vascular endothelial cell function, and manages renal anemia (**Figure 1**). Vitamin D has protective effects on improving proteinuria and progression of renal function in CKD patients. Vitamin D deficiency is independently associated with increased morbidity and mortality in critical illness and a biomarker to predict AKI. Thus, more trials are needed to provide more evidence for clinical application of the pleiotropic influence of vitamin D on the immunological, metabolic, cardiovascular, and renal effects in patients with kidney disease.

**Figure 1. Pleiotropic effects of vitamin D in kidney disease**. Vitamin D exerts beneficial effects on immunological,

metabolic, cardiovascular, and renal effects in patients with kidney disease.

response.

**6. Conclusion**

62 A Critical Evaluation of Vitamin D - Clinical Overview

This study was supported by research grants from the National Science Council (NSC 101-2314-B-016-061-MY3), and the Tri-Service General Hospital (TSGH-C104-008-S03), Taiwan to CC Wu.
