MO714MEAN PLATELET VOLUME / PLATELET COUNT RATIO IN PERITONEAL DIALYSIS: ASSOCIATION TO PERITONEAL TRANSPORT STATUS

Background and Aims Mean platelet volume volume (MPV) is gaining scientific interest with regard to cardiovascular risk stratification. The MPV/platelet count ratio seems to be more specific than mean platelet volume alone as a surrogate parameter for platelet activation. The MPV/platelet ratio might be of interest in peritoneal dialysis (PD) as the distribution and integrity of endothelial – platelet interaction in the abdominal space determines its function. The aim of the study was to evaluate the associations between MPV/platelet ratio and peritoneal transport status. Method In 123 PD patients (median age 65 years) MPV and platelet count were measured together with anthropometric patient data and peritoneal function at catheter placement and after 6 months during the first peritoneal equilibration test (PET). MPV and platelet count were determined with a fully-automated hematological analyzer. Correlation analysis was performed. Results The MPV/platelet ratio decreased significantly from 3.99% at placement to 3.50% at the first PET (median values, Wilcoxon test p<0.001). Neither anthropometric data, nor creatinine clearance, nor BUN clearance, nor Kt/V (renal, peritoneal, total), nor erythrocyte sedimentation rate, nor C reactive protein were associated to MPV/platelet ratio. Only D/P urea and D/P creatinine were significantly correlated to MPV/platelet ratio (D/P urea r=0.223, p=0.01; D/P creatinine r=0.199, p=0.03). Slow transporters presented a significantly lower MPV/platelet ratio than average transporters (median values, 3.49% versus 3.83%, Mann-Whitney test p=0.03). Conclusion Peritoneal dialysis is reducing significantly the MPV/platelet ratio. Differences in MPV/platelet ratio are reflected in the peritoneal transport status at 6 months after dialysis start. The reduction of the MPV/platelet ratio might respect a reduced platelet and endothelial activation even in the abdominal space.

Long-term sonographic evaluation of the peritoneum in peritoneal dialysis patients: A retrospective cohort study

Background Long-term peritoneal dialysis (PD) causes morphological changes to the peritoneum. However, the sequential morphological changes of the peritoneum remain unclear due to the invasiveness and ethical dilemmas surrounding peritoneal biopsies. We aimed to evaluate these long-term morphological peritoneal changes using sonography, which was recently reported to be useful for morphological peritoneal evaluation. Methods We retrospectively identified 115 PD patients who underwent sonographic peritoneal membrane thickness (PMT) measurement. Univariate and multivariate linear regression analyses identified factors related to PMT at baseline (bPMT), at last measurement (lPMT), and the PMT change rate. Of the 115 patients, 42 patients had at least two PMT measurements, including a bPMT measurement. We evaluated the PMT change between bPMT and lPMT. We also evaluated the annual PMT change for 3 years before PD withdrawal in patients who discontinued PD due to peritoneal dysfunction. Clinical characteristics and parameters were analyzed according to PMT change rates (≤ 0 [n = 28] or > 0 [n = 20]). Results The mean age at PD introduction and mean PD duration were 63.7 ± 12.7 years and 40.5 ± 30.1 months, respectively. There was a significant positive correlation between the dialysate to plasma ratio of creatinine (D/P Cr) and lPMT (r = 0.386, p = 0.004), but not bPMT (r=-0.114, p = 0.326). In the multivariate analyses, D/P Cr remained an independent predictor of lPMT (r = 0.478, p = 0.001) after adjusting for age, sex, body mass index, PD duration, diabetes, and peritonitis rate. The mean bPMT and lPMT were 0.67 ± 0.15 mm and 0.69 ± 0.10 mm, respectively, without statistical difference (p = 0.49). Annual PMTs for 3 years before PD withdrawal were 0.67 ± 0.13 mm, 0.66 ± 0.11 mm, and 0.67 ± 0.08 mm, respectively, with no significant differences among measurements (p = 0.967). There were no differences in PD duration, the use of a dialysate containing over 2.5% glucose or icodextrin, and the peritonitis rate between groups divided by the PMT change rate. Conclusions PMT, measured by sonography, was positively correlated with peritoneal permeability. Repeated evaluation of the peritoneum by sonography will enable the recognition of transition in peritoneal function in real time and allow for more appropriate PD management. Furthermore, the peritoneum was not necessarily thickened regardless of PD duration or cause of withdrawal.

Association of adipocytokines with peritoneal function

Background: Preservation of peritoneal function is crucial for the continuation of peritoneal dialysis (PD). A previous study suggested that blood cholesterol is involved in the preservation of peritoneal function; therefore, we determined whether adipocytokines can predict peritoneal function preservation. Methods: Eighty patients were enrolled. Serum adiponectin, leptin, apelin, various blood components, and estimated glomerular filtration rate (eGFR) (mL/min/m2) were measured. In addition, the duration of PD, presence or absence of peritonitis and diabetes mellitus, body mass index, urine output, peritoneal Kt/ V, renal Kt/ V, weekly Kt/ V, peritoneal creatinine clearance rate (CCr), renal CCr, weekly CCr, use or nonuse of statin products, dialysate volume, glucose exposure, and use or nonuse of icodextrin dialysate were assessed. Peritoneal equilibration tests were performed at 6-month intervals, and dialysate-to-plasma [D/P] ratio and glucose uptake ratio [D/D0] were measured. Associations of the baseline values and their percent changes with various adipocytokines and test items were evaluated. Results: Multiple regression analyses identified adiponectin ( p = 0.0392, p = 0.0348) as a significant predictive factor of D/P and D/D0 ratios. eGFR was identified as a significant predictive factor ( p = 0.015) of percent change in the D/P ratio. Apelin ( p = 0.0484), high-density lipoprotein cholesterol ( p = 0.0066), dialysate volume ( p = 0.0223), and urine output ( p = 0.0020) were identified as factors affecting the duration of PD. Conclusions: Adipocytokines are a predictive factor of peritoneal function and the duration of PD in patients undergoing PD.

Advanced glycation end products are associated with immature angiogenesis and peritoneal dysfunction in patients on peritoneal dialysis

Background: Deposition of advanced glycation end products (AGEs) is frequently found in the peritoneum of patients on peritoneal dialysis (PD). Angiogenesis is also observed in the peritoneum. However, the clinical significance of AGEs and angiogenesis in the peritoneum is not fully understood. We evaluated the maturation of capillary vessels and investigated whether AGEs are associated with angiogenesis and peritoneal function in the peritoneal membrane. Methods: Peritoneum obtained when PD catheters were removed from 61 patients with PD was analyzed. The peritoneum was immunohistochemically stained with anti-CD34 (for endothelial cells), anti-alpha smooth muscle actin (αSMA) (for pericytes), and anti-AGE antibodies. We defined CD34-positive and αSMA-negative vessels as immature capillary vessels in peritoneal membranes using serial sections. We evaluated the associations between vessel density, peritoneal function (dialysate-to-plasma ratio for creatinine (D/P creatinine)), and the degree of AGE deposition. Results: AGE accumulation in the interstitium was positively associated with the duration of PD ( p < 0.01). AGE accumulation in the interstitium and vascular wall was positively correlated with the use of acidic solution ( p < 0.05) and the maximum value of D/P creatinine ( p < 0.05). AGE accumulation in the vascular wall was significantly associated with immature capillary density (CD34+/αSMA−) in the peritoneum ( p < 0.01). Vessel density was not significantly correlated with the last measurement of D/P creatinine ( p = 0.126, r = 0.202), However, immature capillary density was positively correlated with the last measurement of D/P creatinine ( p < 0.05, r = 0.278). Conclusions: AGE accumulation is significantly associated with immature angiogenesis and peritoneal dysfunction in patients undergoing PD.

Long-Term Peritoneal Dialysis Treatment Provokes Activation of Genes Related to Adaptive Immunity

Permanent irritation of the peritoneum during peritoneal dialysis (PD) treatment leads to local chronic inflammation and subsequently activation of processes driving fibrogenesis in the long-term. The aim of the study was to compare the peritoneal effluent transcriptome of 20 patients treated less and 13 patients treated more than 2 years using microarray analysis. An increased expression of genes associated with an immune response was observed in long-term treated patients with well preserved peritoneal function, when compared to patients treated less than 2 years. From 100 genes highly expressed in long-term patients, a significant up-regulation of six was found by RT-qPCR: LY9 (lymphocyte antigen 9), TNSFR4 (tumor necrosis factor receptor superfamily, member 4), CD 79A (CD79a molecule), CCR7 (chemokine C-C receptor 7), CEACAM1 (carcinoembryonic antigen-related cell adhesion molecule 1) and IL2RA (interleukin 2 receptor alpha chain). Furthermore, the effluent cell population was analysed. A positive relationship between the number of granulocytes and NK cells on one hand, and duration of PD treatment on the other, was shown. We conclude, that the mechanisms of adaptive immunity promoting T helper 2 cells response are activated in the long-term before functional alterations develop. It consequently might trigger the fibrosis promoting processes.

Peritoneal dialysis - associated peritonitis during treatment with continuous ambulatory peritoneal dialysis

Infections associated with peritoneal dialysis (infection of the catheter, tunnel infection and peritonitis) are the most common complications of this method. Despite significant progress in the methodological approaches to the prevention, diagnosis and treatment of PD associated infections, peritonitis remains the main risk factor for mortality in PD patients (up to 6%) and plays a significant role in more than 1/6 of the deaths associated with non-infectious complications such as cardiovascular and / or cerebrovascular disease. Besides, PD-associated infections are the most common cause of loss of peritoneal function and the patients’ transition to hemodialysis treatment. About 5% of PD patients are converted to hemodialysis treatment in the first year after postponed peritonitis.

After peritoneal dialysis discontinuation: When will we remove peritoneal dialysis catheter?

Most of the peritoneal dialysis patients stop their peritoneal dialysis therapy and transfer to hemodialysis or kidney transplantation. In Japan, most end-stage kidney disease patients select hemodialysis after peritoneal dialysis discontinuation. Peritoneal dialysis catheter will be removed after stopping peritoneal dialysis. If peritoneal dialysis patients suffer from refractory peritonitis or severe tunnel infection, we remove the peritoneal dialysis catheter immediately. However, the causes of peritoneal dialysis discontinuation are ultrafiltration failure or peritoneal membrane dysfunction, and we have to consider the timing of peritoneal dialysis catheter removal. Encapsulating peritoneal sclerosis is the most important adverse event of peritoneal dialysis. And encapsulating peritoneal sclerosis often develops after stopping peritoneal dialysis. Risk factors associated with encapsulating peritoneal sclerosis are high peritoneal equilibration test values, longer peritoneal dialysis period, frequent peritonitis, and so on. There is no evidence to prevent encapsulating peritoneal sclerosis completely. Therefore, we can preserve the peritoneal dialysis catheter and assess the changes of peritoneal function after peritoneal dialysis discontinuation, if patient is suspected to have high risk of encapsulating peritoneal sclerosis.