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.

Repeat Kidney Transplant in a Patient With a Double Inferior Vena Cava and Difficult Venous Access: A Case Report.

Many obstacles may complicate renal transplant, the preferred treatment for end-stage renal disease. Anatomic anomalies are of special importance during surgery. Double inferior vena cava is a rare anomaly reported in 0.2% to 3% of the population and may complicate renal transplant in certain cases. We present a case of a 29-year-old man with end-stage renal disease who was scheduled for repeat kidney renal transplant from a living related donor. His transplant posed many challenges to the transplant team. These included (1) difficult access for dialysis, which required transhepatic insertion of a dialysis catheter, (2) anomalous inferior vena cava anatomy with a double inferior vena cava, (3) a blocked right inferior vena cava, and (4) a small blocked bridging vein connecting the right inferior vena cava to an additional left inferior vena cava. A stent was inserted into the bridging vein to allow venous drainage from the graft. During the transplant procedure, the donated kidney was transplanted into the left iliac fossa and anastomosed to the left external iliac vein. The surgery was successful, without major operative or postoperative complications. The patient was discharged with normal renal function and enjoys normal renal function 6 months after surgery. This case emphasizes the importance of pretransplant evaluation and preparation and the need for high index of suspicion for anatomic variants in donors and recipients.

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.

Let-7 and MicroRNA-148 Regulate Parathyroid Hormone Levels in Secondary Hyperparathyroidism.

Secondary hyperparathyroidism commonly complicates CKD and associates with morbidity and mortality. We profiled microRNA (miRNA) in parathyroid glands from experimental hyperparathyroidism models and patients receiving dialysis and studied the function of specific miRNAs. miRNA deep-sequencing showed that human and rodent parathyroids share similar profiles. Parathyroids from uremic and normal rats segregated on the basis of their miRNA expression profiles, and a similar finding was observed in humans. We identified parathyroid miRNAs that were dysregulated in experimental hyperparathyroidism, including miR-29, miR-21, miR-148, miR-30, and miR-141 (upregulated); and miR-10, miR-125, and miR-25 (downregulated). Inhibition of the abundant let-7 family increased parathyroid hormone (PTH) secretion in normal and uremic rats, as well as in mouse parathyroid organ cultures. Conversely, inhibition of the upregulated miR-148 family prevented the increase in serum PTH level in uremic rats and decreased levels of secreted PTH in parathyroid cultures. The evolutionary conservation of abundant miRNAs in normal parathyroid glands and the regulation of these miRNAs in secondary hyperparathyroidism indicates their importance for parathyroid function and the development of hyperparathyroidism. Specifically, let-7 and miR-148 antagonism modified PTH secretion in vivo and in vitro, implying roles for these specific miRNAs. These findings may be utilized for therapeutic interventions aimed at altering PTH expression in diseases such as osteoporosis and secondary hyperparathyroidism.

Carbapenem-resistant Klebsiella pneumoniae is associated with poor outcome in hemodialysis patients.

BACKGROUND: Hemodialysis (HD) units have become a source of resistant bacteria. One of the most alarming developments is the emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP). Risk factors and outcomes of CRKP isolation in HD patients have not been previously studied. METHODS: A nested case-control study was conducted in maintenance HD patients between January 1st 2006 and June 30th 2009. CRKP-positive patients were matched with randomly selected CRKP-negative HD patients. Demographics, clinical and laboratory data were collected for 24 months prior to the specimen collection. Multivariate analyses identified independent risk factors for CRKP. A prospective follow-up determined CRKP-associated outcome. RESULTS: Demographics associated with CRKP acquisition in HD patients were age between 65 and 75 and having no living offspring. Clinical conditions associated with CRKP were previous hospitalization, temporary HD catheter and previous isolation of vancomycin-resistant enterococcus. CRKP-related outcome was poor: median survival of one month and a hazard ratio [95% CI] of 5.9 [3.2-11.0] for mortality. CONCLUSIONS: Temporary HD catheters and previous treatment for VRE may predict subsequent CRKP isolation. A microbiological diagnosis of CRKP in HD patients is highly associated with imminent mortality. Meticulous measures to control the spread of CRKP bacteria among HD patients appear particularly warranted.

The peptidyl-prolyl isomerase Pin1 determines parathyroid hormone mRNA levels and stability in rat models of secondary hyperparathyroidism.

Secondary hyperparathyroidism is a major complication of chronic kidney disease (CKD). In experimental models of secondary hyperparathyroidism induced by hypocalcemia or CKD, parathyroid hormone (PTH) mRNA levels increase due to increased PTH mRNA stability. K-homology splicing regulator protein (KSRP) decreases the stability of PTH mRNA upon binding a cis-acting element in the PTH mRNA 3' UTR region. As the peptidyl-prolyl isomerase (PPIase) Pin1 has recently been shown to regulate the turnover of multiple cytokine mRNAs, we investigated the role of Pin1 in regulating PTH mRNA stability in rat parathyroids and transfected cells. The data generated were consistent with Pin1 being a PTH mRNA destabilizing protein. Initial analysis indicated that Pin1 activity was decreased in parathyroid protein extracts from both hypocalcemic and CKD rats and that pharmacologic inhibition of Pin1 increased PTH mRNA levels posttranscriptionally in rat parathyroid and in transfected cells. Pin1 mediated its effects via interaction with KSRP, which led to KSRP dephosphorylation and activation. In the rat parathyroid, Pin1 inhibition decreased KSRP-PTH mRNA interactions, increasing PTH mRNA levels. Furthermore, Pin1-/- mice displayed increased serum PTH and PTH mRNA levels, suggesting that Pin1 determines basal PTH expression in vivo. These results demonstrate that Pin1 is a key mediator of PTH mRNA stability and indicate a role for Pin1 in the pathogenesis of secondary hyperparathyroidism in individuals with CKD.