Vitamin D belongs to the group of liposoluble steroids mainly involved in bone metabolism by modulating calcium and phosphorus absorption or reabsorption at various levels, as well as parathyroid hormone production. Recent evidence has shown the extra-bone effects of vitamin D, including glucose homeostasis, cardiovascular protection, and anti-inflammatory and antiproliferative effects. This narrative review provides an overall view of vitamin D’s role in different settings, with a special focus on chronic kidney disease and kidney transplant.

Introduction: Renal allograft biopsy is the gold standard for the detection of histological lesions of chronic allograft dysfunction. The identification of a noninvasive routine test would be desirable. Elastosonography is used to assess tissue stiffness according to viscosity, and no data are available on the use of point quantification shear-wave elastography (ElastPQ) for the evaluation of renal chronic lesions. Research Question: To evaluate the feasibility of ElastPQ to assess cortical allograft stiffness and to determine the correlation of clinical, biological, and pathological factors with the diagnostic accuracy of kidney stiffness values in patients with histological lesions. Design: Forty-two patients underwent kidney transplant biopsy and 10 valid measurements of ElastPQ, blindly performed by 2 operators. The interobserver reproducibility was assessed according to intraclass correlation coefficient. The ElastPQ measurements and the clinical data were compared using the Spearman correlation analysis. Results: 97.6% reliable measurements were obtained using ElastPQ, with an excellent interobserver agreement. The kidney stiffness was significantly higher in the patients with a time since transplantation >12 months and was correlated with chronic lesions (interstitial fibrosis, tubular atrophy transplant glomerulopathy, and mesangial matrix), with the interstitial fibrosis/tubular atrophy, score and with the sum of the scores of the chronic lesions. Mesangial matrix increase is the only independent determinant of kidney stiffness. Discussion: ElastPQ is a noninvasive, reproducible, and sensitive diagnostic tool able to detect moderate/severe chronic lesions. Its routine use during follow-up can identify patients eligible for biopsy, which remains the gold standard exam for detecting chronic allograft dysfunction.

Background and Objectives: Endovascular aneurism repair (EVAR) is a minimally invasive alternative to open surgery for the treatment of abdominal aortic aneurysm. Iodine contrast medium (ICM) is considered the gold standard, at the high price of related nephrotoxicity and allergic reactions. Carbon dioxide (CO2) has been suggested as an alternative non-nephrotoxic contrast media agent. We aimed to evaluate the safety and the renal impact of the administration of CO2, compared with ICM in EVAR procedures. Design, Setting, Participants, and Measurements: We retrospectively reviewed data of patients who underwent EVAR at the Vascular Surgery Department of the Sant’Orsola Hospital in Bologna. Estimated glomerular filtration rate (eGFR) was evaluated before intervention, immediately after and at 12 months. Results: In total, 22 patients received CO2 and low-dose ICM (CO2 Group) and 22 received standard ICM (Control Group), matched for clinical characteristics and renal function at the time of procedure. Pre and post-operative renal function values (eGFR) were compared between the two groups: in the immediate post-operative the group treated with CO2 and low-dose ICM globally showed a slight improvement in renal function (mean eGFR +5.10%±3.2), meanwhile the group treated with standard dose of ICM presented a significant worsening of renal function compared with pre-procedure values (mean eGFR −9.65%±4). Incidence of post-contrast acute kidney injury (PC-AKI) was 9% in the CO2 group vs 27% in the Control group. At 12 months, the renal impairment was significantly greater in the ICM group than in the CO2 group (mean eGFR decrease −19.2%±11.1 and −7.40%±3.5, respectively). Conclusions: Administration of either CO2 alone or along with low-dose ICM showed to be safer than full-dose ICM alone, lowering the incidence of PC-AKI in patients undergoing EVAR. Unexpectedly, our study revealed also a significant worsening of renal function in patients treated with standard dose of ICM in 1-year follow-up, introducing the concept that acute renal damage caused by ICM could elicit a chronic injury process that affect long-term renal outcomes. Clinical Impact: Evaluating the safety and the renal impact of the administration of CO2, compared to Iodinate Contrast Medium, in EVAR procedures represents a first step in order to further tayloring medical procedures on patients characteristics. Our findings can guide the clinicians and surgeons in the procedures choice, not considering only the immediate effect of ICM on renal function but also the potential long-term effects.

Background: Sodium prescription in patients with intradialytic hypotension remains a challenge for the attending nephrologist, as it increases dialysate conductivity in hypotension-prone patients, thereby adding to dietary sodium levels. Methods: New sodium prescription strategies are now available, including the use of a mathematical model to compute the sodium mass to be removed during dialysis as a physiological controller. Results: This review describes the sodium load of patients with end-stage renal disease on chronic hemodialysis (HD) and discusses 2 strategies to remove excess sodium in patients prone to intradialytic hypotension, namely, Profiled HD and the hemodiafiltration Aequilibrium System. Conclusion: The Profiled HD and Aequilibrium System trial both proved effective in counteracting intradialytic hypotension.

Hemodialysis (HD) is known to trigger a chronic inflammatory status, affecting the innate and acquired immune response. This study was aimed at a comparative analysis of immune cell subsets, proliferation, and apoptosis in subjects receiving chronic HD treatment with respect to a healthy control. Regardless of the dialysis filter used, we observed a reshaping of the acquired immune component both with respect to healthy patients and between the various sessions of dialysis treatment, with an impairment of CD3 cells, along with an increase in CD4 and CD8 cell populations producing pro-inflammatory factors such as IL-17 and IFN-gamma. The population of B cells, monocytes and NK cells were not impaired by the dialysis procedure. These results confirmed the high impact of the HD treatment on the patient’s immune system, underlying the imbalance of T cell counterparts.