Vitamin D in organ transplantation

Abstract

Vitamin D deficiency is prevalent among patients with end-stage organ failure awaiting transplant. Low serum 25-hydroxyvitamin D (25-OHD) levels in these patients may be related to many disease-specific factors, as well as decreased sunlight exposure and limited intake of foods containing vitamin D. Low serum 25-OHD levels are also extremely common following solid organ transplantation, both during the immediate postoperative period and in long-term graft recipients. Demographic and lifestyle factors are important in determining D status in transplant recipients. Worse vitamin D status is associated with poorer general health, lower albumin, and even decreased survival among these patients. Although several studies have demonstrated that active forms of vitamin D and its analogues prevent bone loss following transplantation, the data do not show consistent benefit. These therapies may have particular utility after renal transplantation. However, given the narrow therapeutic window with respect to hypercalcemia and hypercalciuria, and the demonstrated efficacy of bisphosphonates to prevent post-transplantation bone loss, we regard these agents as adjunctive rather than primary therapy for transplantation osteoporosis. The effects of 1,25(OH)2D on the immune system, which are still being elucidated, may have potential for reducing infections and preventing allograft rejection after transplantation.

Longitudinal Analysis of Vascular Function and Biomarkers of Metabolic Bone Disorders before and after Renal Transplantation

“…Vitamin D insufficiency or deficiency is almost universal in 5D-CKD [13]. After transplantation, 25-hydroxy-vitamin D (25OHVD) levels increase, but vitamin D insufficiency or frank deficiency remain pervasive in transplant patients [14,15]. Vascular function, as measured by the endothelium-dependent vasodilatory response to ischemia in the forearm, represents a cogent surrogate end point in clinical research because it is strongly associated with incident cardiovascular outcomes in various settings, including community level studies, studies in patients with hypertension or with coronary heart disease [16] and in dialysis patients [17].…”

Vitamins Status Following Solid Organ Transplantation

“…Vitamin D deficiency was reported in transplant candidates with congestive heart failure, end-stage pulmonary disease, liver failure and most commonly, chronic kidney disease (24). Transplantation unfortunately will not restore vitamin D status regardless of the transplanted organ.…”

“…Estimates of prevalence of vitamin D deficiency following transplantation were variable according to patient populations, type of transplanted organ, and, probably, the measurement assay of 25-hydroxy metabolite. The vitamin D insufficiency is not uncommon and an estimated 26-33% developed severe deficiency [24]. Low vitamin D levels were suggested to be utilized as a predictor of worsening of graft function and increasing proteinuria [1].…”

Update on lung transplantation: programmes, patients and prospects

“…In older LTR, cardiovascular complications are also common and include diastolic dysfunction, coronary artery disease, atrial fibrillation particularly in the perioperative transplant period and, later on, systemic hypertension and hyperlipidaemia [307]. Other significant complications that can be exacerbated by routine posttransplant medications include myelosuppression [308], glucose intolerance and diabetes [309], electrolyte disorders, gonadal dysfunction and osteoporosis [310][311][312].…”

“…Similarly, the high prevalence of osteopaenia and osteoporosis in patients with advanced lung disease (especially in those with low body mass index and chronic steroid use) and LTx was well recognised from the beginning. More recently, there has been an increasing interest in identifying different patterns of bone loss (as defined by bone densitometry) in the setting of posttransplant immunosuppression but ''adequate'' vitamin D, calcium and bisphosphonate therapy and then relating this information to overall bone strength and the development of fractures [311,[334][335][336].…”