Successful kidney transplantation normalizes platelet function

The modulation of platelet function by growth hormone in growth hormone deficient Hypopituitary patients

BACKGROUND

Growth hormone deficiency (GHD) has been implicated in increased cardiovascular and cerebrovascular disease risk seen in hypopituitarism, however the mechanism remains speculative. We hypothesise that platelet abnormalities may play a contributory role. Herein we examined platelet behaviour in GHD hypopituitary patients, pre- and post-growth hormone (GH) replacement.

METHODS

This study utilizes a physiological flow-based assay to quantify platelet function in whole blood from patient cohorts under arterial shear. Thirteen GH Naïve hypopituitary adults with GHD and thirteen healthy matched controls were studied. Patients were assessed before and after GH treatment. All other pituitary replacements were optimised before the study. In addition to a full endocrine profile, whole blood was labelled and perfused over immobilised von Willibrand factor (vWF). Seven parameters of dynamic platelet-vWF interactions were recorded using digital image microscopy and analysed by customised platelet tracking software.

RESULTS

We found a significantly altered profile of platelet-vWF interactions in GHD individuals compared to healthy controls. Specifically, we observed a marked increase in platelets shown to form associations such as tethering, rolling and adherence to immobilized vWF, which were reduced post GH treatment. Speed and distance platelets travelled across vWF was similar between controls and pre-therapy GHD patients, however, this was considerably increased post treatment. This may indicate reduced platelet signaling resulting in less stable adhesion of platelets post GH treatment.

CONCLUSIONS

Taken together observed differences in platelet behaviour may contribute to an increased risk of thrombosis in GHD which can in part be reversed by GH therapy.

Ortalama trombosit hacmi ve ortalama trombosit hacmi/trombosit sayısı oranının periton diyalizi başlandıktan bir yıl sonraki değişimi

Aim: Cardiovascular diseases are the most common cause of mortality in patients undergoing peritoneal dialysis. Thrombocyte indices which are indicators of platelet activation are predictors of cardiovascular events. We aim to examine the change in platelet count, mean platelet volume, and mean platelet volume to platelet count ratio one year after initiation of peritoneal dialysis in patients with end-stage renal disease. Materials and Methods: This retrospective study included 28 patients. Demographic and clinical characteristics of the patients at the time of initiation of peritoneal dialysis were recorded from the patient files. Laboratory data within the last month before the initiation of peritoneal dialysis and in the first year were recorded from the patient files. The mean platelet volume to platelet count ratio was calculated as mean platelet volume (femtolitres) divided by platelet count (number of thousand platelets/microliter). Results: The mean age was 51.1 ± 14.6 years, and 42.8% of the patients were male. Diabetic nephropathy and hypertensive nephropathy were the most common causes of end-stage renal disease. One year after the initiation of peritoneal dialysis, the urea level decreased significantly, and C-reactive protein level increased significantly. Platelet count increased from 240 ± 55 x10 3 /μL to 274 ± 53 x10 3 /μL (p=0.003) and mean platelet volume decreased from 10.7 ± 1.0 fl to 10.2 ± 0.8 fl (p

Impact of transplantation on neutrophil extracellular trap formation in patients with end-stage renal disease: A single-center, prospective cohort study

ABSTRACT

Increased neutrophil extracellular trap (NET) formation associates with high cardiovascular risk and mortality in patients with end-stage renal disease (ESRD). However, the effect of transplantation on NETs and its associated markers remains unclear. This study aimed to characterize circulating citrullinated Histone H3 (H3cit) and Peptidyl Arginase Deiminase 4 (PAD4) in ESRD patients undergoing transplantation and evaluate the ability of their neutrophils to release NETs.This prospective cohort study included 80 healthy donors and 105 ESRD patients, out of which 95 received a transplant. H3cit and PAD4 circulating concentration was determined by enzyme-linked immunosorbent assay in healthy donors and ESRD patients at the time of enrollment. An additional measurement was carried out within the first 6 months after transplant surgery. In vitro NET formation assays were performed in neutrophils isolated from healthy donors, ESRD patients, and transplant recipients.H3cit and PAD4 levels were significantly higher in ESRD patients (H3cit, 14.38 ng/mL [5.78-27.13]; PAD4, 3.22 ng/mL [1.21-6.82]) than healthy donors (H3cit, 6.45 ng/mL [3.30-11.65], P < .0001; PAD4, 2.0 ng/mL [0.90-3.18], P = .0076). H3cit, but not PAD4, increased after transplantation, with 44.2% of post-transplant patients exhibiting high levels (≥ 27.1 ng/mL). In contrast, NET release triggered by phorbol 12-myristate 13-acetate was higher in neutrophils from ESRD patients (70.0% [52.7-94.6]) than healthy donors (32.2% [24.9-54.9], P < .001) and transplant recipients (19.5% [3.5-65.7], P < .05).The restoration of renal function due to transplantation could not reduce circulating levels of H3cit and PAD4 in ESRD patients. Furthermore, circulating H3cit levels were significantly increased after transplantation. Neutrophils from transplant recipients exhibit a reduced ability to form NETs.

Comparative Analysis of Risk Factors in Declined Kidneys from Donation after Brain Death and Circulatory Death

Background and objectives: Kidneys from donation after circulatory death (DCD) are more likely to be declined for transplantation compared with kidneys from donation after brain death (DBD). The aim of this study was to evaluate characteristics in the biopsies of human DCD and DBD kidneys that were declined for transplantation in order to rescue more DCD kidneys. Materials and Methods: Sixty kidney donors (DCD = 36, DBD = 24) were recruited into the study and assessed using donor demographics. Kidney biopsies taken post cold storage were also evaluated for histological damage, inflammation (myeloperoxidase, MPO), von Willebrand factor (vWF) expression, complement 4d (C4d) deposition and complement 3 (C3) activation using H&E and immunohistochemistry staining, and Western blotting. Results: More DBD donors (16/24) had a history of hypertension compared with DCDs (8/36, p = 0.001). The mean warm ischemic time in the DCD kidneys was 12.9 ± 3.9 min. The mean cold ischemic time was not significantly different between the two groups of kidney donors (DBD 33.3 ± 16.7 vs. DCD 28.6 ± 14.1 h, p > 0.05). The score of histological damage and MPO, as well as the reactivity of vWF, C4d and C3, varied between kidneys, but there was no significant difference between the two donor types (p > 0.05). However, vWF reactivity might be an early indicator for loss of tissue integrity, while C4d deposition and activated C3 might be better predictors for histological damage. Conclusions: Similar characteristics of DCD were shown in comparison with DBD kidneys. Importantly, the additional warm ischemic time in DCD appeared to have no further detectable adverse effects on tissue injury, inflammation and complement activation. vWF, C4d and C3 might be potential biomarkers facilitating the evaluation of donor kidneys.

End-Stage Kidney Disease Is Overlooked as a Proximate Cause of Death at Autopsy

OBJECTIVES

To determine how often end-stage kidney disease (ESKD) is implicated as a cause of death (COD) at autopsy.

METHODS

We searched our autopsy database (2007-2017) using queries "end-stage renal disease," "end-stage kidney disease," "ESRD," "chronic renal disease," and "chronic kidney disease." Final diagnosis and summaries were reviewed to determine if ESKD was appropriately correlated with the COD. Cases in which the COD was unrelated to kidney function were excluded.

RESULTS

Eighty-five patients with a history of ESKD and histologic confirmation thereof were identified. Their CODs were cardiovascular (36%), infection/sepsis (41%), pulmonary (6%), gastrointestinal/hepatic (2%), central nervous system (3%), other systemic disease (7%), and unspecified (5%). ESKD was implicated as a contributing COD in 24 (28%) cases.

CONCLUSIONS

ESKD is often overlooked at autopsy, particularly in patients with cardiovascular or infectious disease. Accurate documentation of ESKD contributing to mortality is important for education, counseling, record maintenance, and directing research efforts.

Correlation Between Stem and Progenitor Cells Number and Immune Response in Patients After Allogeneic Kidney Transplant

Background

Stem and progenitor cells are of great interest in all medical procedures involving tissue regeneration. There is a consensus that the use of stem cells after solid organ transplantation may play a role in tissue repair and in immunosuppression. The aim of this study was to determine possible relations between stem cell count and the immune response in a group of patients after kidney transplantation.

Material/Methods

The study was conducted on a group of 100 patients who underwent kidney transplantation. The following phenotypic markers of the studied cell subpopulations were adopted: T_reg cells (CD3⁺CD4⁺CD25^high), circulating hematopoietic cells (CD34⁺CD133⁺CD45⁺CD38⁻), and non-hematopoietic cells (Lin⁻CXCR4⁺CD133⁻CD45⁻). Cell subpopulations were assessed using LSRII flow cytometer (BD Biosciences, San Jose, CA, USA).

Results

Positive correlation was observed between non-hematopoietic stem cells percentage and recipient’s platelets count (P=0.04). Moreover, a higher percentage of non-hematopoietic cells was accompanied by lower numbers of B lymphocytes (P=0.03) and T_reg cells (P=0.02).

Conclusions

Our study revealed significant associations between the intensity of ongoing immune response processes and tissue damage, and the release of stem and progenitor cells into circulation. These findings suggest their role in the stimulation of protective processes in terms of graft regeneration.