Impact of tozinameran (BNT162b2) mRNA vaccine on kidney transplant and chronic dialysis patients: 3-5 months follow-up.

BACKGROUND: Determining the humoral immunogenicity of tozinameran (BNT162b2) in patients requiring chronic renal replacement therapy, and its impact on COVID-19 morbidity several months after vaccination, may guide risk assessment and changes in vaccination policy. METHODS: In a prospective post-vaccination cohort study with up to 5 months follow-up we studied outpatient dialysis and kidney transplant patients and respective healthcare teams. Outcomes were anti S1/S2 antibody responses to vaccine or infection, and infection rate during follow-up. RESULTS: One hundred seventy-five dialysis patients (40% women, 65 ± 15 years), 252 kidney transplant patients (33% women, 54 ± 14 years) and 71 controls (65% women, 44 ± 14 years) were followed. Three months or longer after vaccination we detected anti S1/S2 IgG antibodies in 79% of dialysis patients, 42% of transplant recipients and 100% of controls, whereas respective rates after infection were 94%, 69% and 100%. Predictors of non-response were older age, diabetes, history of cancer, lower lymphocyte count and lower vitamin-D levels. Factors associated with lower antibody levels in dialysis patients were modality (hemodialysis vs peritoneal) and high serum ferritin levels. In transplant patients, hypertension and higher calcineurin or mTOR inhibitor drug levels were linked with lower antibody response. Vaccination was associated with fewer subsequent infections (HR 0.23, p < 0.05). Moreover, higher antibody levels (particularly above 59 AU/ml) were associated with fewer events, with a HR 0.41 for each unit increased in log10titer (p < 0.05). CONCLUSIONS: Dialysis patients, and more strikingly kidney transplant recipients, mounted reduced antibody response to COVID-19 mRNA vaccination. Lesser humoral response was associated with more infections. Measures to identify and protect non-responsive patients are required.

The Effect of a 26-Hour Fast in Living Kidney Donors.

BACKGROUND: Living kidney donation is widely practiced, and short- and long-term outcomes are acceptable. Within the living kidney donor population there are unique ethnic groups who practice customs that affect kidney function. In Judaism, Yom Kippur (Day of Atonement) is a 25- to 26-hour fast practiced yearly. There are no studies describing the effect of this fast on LKDs. METHODS: Living kidney donors were approached via e-mail. Exclusion criteria were conditions considered prohibitive of fasting. Control participants were potential living kidney donors approved by the standard medical evaluation but that had not yet donated. Blood and urine samples were obtained at 3 time points: baseline: 3 months before fast; fasting: 1 hour after fast; and follow-up: 14 days after fast. RESULTS: In total, 85 living kidney donors and 27 control participants were included. Donors were older (42.8 vs 38.8 years) and had a higher baseline creatinine (103 vs 72 umol/L). All other parameters were the same. The percent change between fasting and nonfasting creatinine was smaller in living kidney donors than in control participants (0.12% vs 0.21% change, P = .04). Values of sodium, albumin, and osmolarity were not different between groups. Time from donation did not influence results. CONCLUSIONS: Living kidney donors practicing a day fast showed a different pattern regarding the change in creatinine levels. This pattern cannot be considered hazardous for living kidney donors. The emotional wellbeing of living kidney donors is of utmost importance, and this first report of the safety of a 24-hour fast is reassuring. These findings may be of interest to other religious groups, for example, the Muslim community which observes Ramadan.

Ambulatory monitoring unmasks hypertension among kidney transplant patients: single center experience and review of the literature.

BACKGROUND: Disagreements between clinic and ambulatory blood pressure (BP) measurements are well-described in the general population. Though hypertension is frequent in renal transplant recipients, only a few studies address the clinic-ambulatory discordance in this population. We aimed to describe the difference between clinic and ambulatory BP in kidney transplant patients at our institution. METHODS: We compared the clinic and ambulatory BP of 76 adult recipients of a kidney allograft followed at our transplant center and investigated the difference between these methods, considering confounding by demographic and clinical variables. RESULTS: Clinic systolic BP (SBP) and diastolic BP (DBP) were 128 ± 13/79 ± 9 mmHg. Awake SBP and DBP were 147 ± 18/85 ± 10 mmHg. The clinic-minus-awake SBP and DBP differences were - 18 and - 6 mmHg, respectively. The negative clinic-awake ΔSBP was more pronounced at age > 60 years (p = 0.026) and with tacrolimus use compared to cyclosporine (p = 0.046). Sleep SBP and DBP were 139 ± 21/78 ± 11 mmHg. A non-dipping sleep BP pattern was noted in 73% of patients and was associated with tacrolimus use (p = 0.020). CONCLUSIONS: Our findings suggest pervasive underestimation of BP when measured in the kidney transplant clinic, emphasizes the high frequency of a non-dipping pattern in this population and calls for liberal use of ambulatory BP monitoring to detect and manage hypertension.

Implementation of guidelines for metabolic syndrome control in kidney transplant recipients: results at a single center.

BACKGROUND: Cardiovascular disease is a leading cause of death among kidney transplant recipients. Metabolic syndrome increases the risk for cardiovascular events and decreases graft survival. Lately, guidelines for management of the metabolic syndrome, primarily hypertension, diabetes mellitus (DM) and hypercholesterolemia have dramatically changed in an attempt to decrease cardiovascular risks among kidney transplant recipients. In the present study we examined whether these guideline changes had impact on our management of post-transplantation patients and the subsequent treatment outcomes for these diseases. METHODS: Data were obtained from kidney transplant clinic files from two follow-up (FU) periods-between 1994-1997 and between 2008-2011. Demographic data, monitoring and screening frequency for cardiovascular risk factors, immunosuppression regimen, treatment for hypertension, diabetes and hyperlipidemia, treatment outcomes and graft function changes were compared between the two follow-up periods. RESULTS: There was a significant increase in the percentage of patients undergoing transplantation due to renal failure secondary to diabetes and/or hypertension. Patient monitoring and screening during the second FU period were less frequent, but more targeted, reflecting changes in clinic routines. Blood pressure was better controlled in the second FU period (p < 0.01), as was hypercholesterolemia (p < 0.001). High fasting glucose levels were more prevalent among patients in the second group (p < 0.005), although more patients received treatment for DM (p < 0.001). Significantly, fewer patients experienced deterioration of kidney functions during the second FU period (p < 0.001). CONCLUSIONS: We found that guideline changes had impact on clinical practice, which translated to better control of the metabolic syndrome. DM control is challenging. Overall, stability of kidney function improved.

Serum vitamin D levels in kidney transplant recipients: the importance of an immunosuppression regimen and sun exposure.

BACKGROUND: Vitamin D deficiency was shown to be prevalent among renal transplant recipients in northern countries, but little is known regarding risk factors. OBJECTIVES: To test vitamin D levels in kidney transplant recipients residing closer to the equator, compare them to levels in liver transplant recipients and hemodialysis patients, and identify possible risk factors. METHODS: In a cross-sectional study 103 kidney transplant recipients, 27 liver transplant recipients and 50 hemodialysis patients followed at our institute were tested for vitamin D levels. Demographic data, medical history and current treatment were recorded from the medical files. RESULTS: Inadequate vitamin D levels (< 30 ng/ml) were found in 75% of all patients and 75% of all kidney transplant recipients. Vitamin D levels were higher among dialysis patients than transplant recipients, though deficiency rates were similar. No association was found between kidney function and vitamin deficiency. Deficiency was associated with higher prednisone doses, use of mycophenolate sodium, tacrolimus, and iron supplements, or lower doses of vitamin D supplementation. CONCLUSIONS: Despite potential higher ultraviolet B exposure, inadequate vitamin D levels were prevalent in our study group. Importantly, some immunosuppressive medications were associated with vitamin D deficiency and high doses of vitamin D were associated with less deficiency.

Image denoising via sparse and redundant representations over learned dictionaries.

We address the image denoising problem, where zero-mean white and homogeneous Gaussian additive noise is to be removed from a given image. The approach taken is based on sparse and redundant representations over trained dictionaries. Using the K-SVD algorithm, we obtain a dictionary that describes the image content effectively. Two training options are considered: using the corrupted image itself, or training on a corpus of high-quality image database. Since the K-SVD is limited in handling small image patches, we extend its deployment to arbitrary image sizes by defining a global image prior that forces sparsity over patches in every location in the image. We show how such Bayesian treatment leads to a simple and effective denoising algorithm. This leads to a state-of-the-art denoising performance, equivalent and sometimes surpassing recently published leading alternative denoising methods.