Impact of peritoneal dialysis strategy on technique and patient survival

Background

The aim of this study was to evaluate the impact of peritoneal dialysis (PD) strategy on technique and patient survival.

Methods

This was a retrospective, single-center study conducted on consecutive patients with chronic kidney disease who underwent PD between January 2009 and December 2019. The study sample was stratified into four different groups according to PD technique [automated (APD) or manual (CAPD)] and icodextrin use (yes versus no). The primary endpoints were survival of both technique and patient.

Results

A total of 531 patients were included in the analysis. Mean ± standard deviation age was 60.6 ± 14.6 years, 68.4% (363) were men and 34.8% (185) had diabetes. The median technique survival time was 19 (15) months. A total of 185 (34.8%), 96 (18.1%), 99 (18.7%) and 151 (28.4%) patients were included in the CAPD/No-Icodextrin, CAPD/Icodextrin, APD/No-Icodextrin and APD/Icodextrin study groups, respectively. Throughout the study, 180 (33.9%) patients underwent renal transplant, 71 (13.4%) were changed to hemodialysis and 151 (28.4%) died. Age [hazard ratio (HR) 0.975, 95% confidence interval (CI) 0.960-0.990, P = .001] and incidence of early peritoneal infection (HR 2.440, 95% CI 1.453-4.098, P = .001) were associated with technique survival, while age (HR 1.029, 95% CI 1.013-1.045, P < .001), Charlson Index (HR 1.192, 95% CI 1.097-1.295, P < 0.001), use of icodextrin (HR 0.421, 95% CI 0.247-0.710, P < .001) and APD/Icodextrin (HR 0.499, 95% CI 0.322-0.803, P = .005) were associated with patient survival.

Conclusions

Icodextrin use and APD/Icodextrin had a positive impact on patient survival, while older age and higher Charlson Index had a negative one. Age and incidence of early peritoneal infection significantly impacted on technique survival.

Towards carotenoid biofortification in wheat: identification of XAT-7A1, a multicopy tandem gene responsible for carotenoid esterification in durum wheat

Yellow pigment content, mainly due to the accumulation of carotenoids, is a quality trait in durum wheat grain as it confers the bright yellow color to pasta preferred by consumers. Also, carotenoids are essential nutrients exerting important biological functions in human health. Consequently, biofortification strategies have been developed in many crops to increase carotenoid content. In this context, carotenoid esterification is emerging as a new breeding target for wheat biofortification, as carotenoid esters have been found to promote both carotenoid accumulation and stability. Until recently, no carotenoid esters have been identified in significant proportions in durum wheat grains, and interspecific breeding programs have been started to transfer esterification ability from common wheat and Hordeum chilense.In this work, XAT-7A1 is identified as the gene responsible for carotenoid esterification in durum wheat. Sequencing, copy number variation and mapping results show that XAT-7A1 is organized as tandem or proximal GDSL esterase/lipase copies in chromosome 7A. Three XAT-7A1 haplotypes are described: Type 1 copies, associated with high levels of carotenoid esters (diesters and monoesters) production and high expression in grain development; Type 2 copies, present in landraces with low levels of carotenoid esters (monoesters) or no esters; and Type 3 copies, without the signal peptide, resulting in zero-ester phenotypes.The identification of XAT-7A1 is a necessary step to make the carotenoid esterification ability available for durum and bread wheat breeding, which should be focused on the Type 1 XAT-7A1 haplotype, which may be assessed as a single gene since XAT-7A1 copies are inherited together.

Novel Immune Cell Subsets Exhibit Different Associations With Vascular Outcomes in Chronic Kidney Disease Patients-Identifying Potential Biomarkers

Background and Aims: Alterations in novel immune cell subsets, such as angiogenic T cells (Tang), senescent T cells (CD4⁺CD28^null), and monocyte subsets are associated with impaired vascular homeostasis in several inflammatory conditions. However, mediators underlying vascular deterioration in chronic kidney disease (CKD) are poorly characterized. This study assessed their role in the vascular deterioration of CKD using a broad spectrum of surrogate markers ranging from altered functionality to overt calcification.

Methods: Tang (CD3⁺CD31⁺CXCR4⁺), CD4⁺CD28^null cells, and monocytes [CD14/CD16 subsets and angiotensin-converting enzyme (ACE) expression] were measured in peripheral blood by flow cytometry in 33 CKD stage 5 patients undergoing peritoneal dialysis (CKD5-PD) and 15 healthy controls (HCs). Analyses were replicated in a hemodialysis cohort. Vascular surrogate markers (including adventitial vasa vasorum, pulse wave velocity, intima-media thickness, and vascular calcification) were assessed by appropriate imaging methods.

Results: In CKD5-PD, decreased Tang levels (p < 0.001) were unrelated to clinical features or traditional cardiovascular (CV) risk factors but correlated negatively with troponin T levels (r = −0.550, p = 0.003). Instead, CD4⁺CD28^null frequency was increased (p < 0.001), especially in those with vascular calcifications. Quantitative and qualitative differences were also observed within the monocyte pool, a shift toward CD16⁺ subsets and ACE expression being found in CKD. Equivalent results were observed in the replication cohort. Each subset associated distinctly with adverse vascular outcomes in univariate and multivariate analyses: while Tang depletion was linked to poor vascular function and subclinical atherosclerosis, increases in CD4⁺CD28^null were associated with overt vascular thickening and calcification. Monocytes were not independently associated with vascular outcomes in CKD patients.

Conclusions: Novel T cell and monocyte subsets are altered in CKD. Altered T-cell subpopulations, but not monocytes, exhibited distinct associations with different vascular outcomes in CKD. Tang are emerging biomarkers of subclinical vascular deterioration in CKD.

A subset of low density granulocytes is associated with vascular calcification in chronic kidney disease patients

Inflammation is central to chronic kidney disease (CKD) pathogenesis and vascular outcomes, but the exact players remain unidentified. Since low density granulocytes (LDGs) are emerging mediators in inflammatory conditions, we aimed to evaluate whether LDGs may be altered in CKD and related to clinical outcomes as biomarkers. To his end, LDGs subsets were measured in peripheral blood by flow cytometry and confocal microscopy in 33 CKD patients undergoing peritoneal dialysis and 15 healthy controls (HC). Analyses were replicated in an additional cohort. DEF3 (marker of early granulopoiesis) gene expression on PBMCs was quantified by qPCR. Total CD15+ LDGs and both CD14lowCD16+ and CD14-CD16- subsets were expanded in CKD. The relative frequency of the CD14-CD16- subpopulation was higher among the CD15+ pool in CKD. This alteration was stable over-time. The increased CD14-CD16-CD15+ paralleled Kauppila scores and DEF3 expression, whereas no association was found with CD14lowCD16+ CD15+. Both subsets differed in their CD11b, CD10, CD35, CD31, CD62L, IFNAR1 and CD68 expression, FSC/SSC features and nuclear morphology, pointing to different origins and maturation status. In conclusion, LDGs were expanded in CKD showing a skewed distribution towards a CD14-CD16-CD15+ enrichment, in association with vascular calcification. DEF3 expression in PBMC can be a marker of LDG expansion.

Berardinelli-Seip syndrome in peritoneal dialysis

A case of Berardinelli-Seip syndrome, a congenital generalised lipodystrophy, is reported. Symptoms first appeared when the patient was 20 years old. She showed severe insulin resistance as well as micro- and macro-angiopathic complications, including chronic kidney disease, which required renal replacement therapy with peritoneal dialysis. The patient's clinical course was reviewed since paediatric age (when initial signs of the disease being already evident) to present time. Berardinelli-Seip syndrome is very uncommon, and the present case is particularly rare because it is the only case (at least as reported in the literature) in a patient receiving dialysis.

Exit-site infection of peritoneal catheter is reduced by the use of polyhexanide. results of a prospective randomized trial

BACKGROUND

One of the most common and severe complications affecting peritoneal dialysis (PD) patients is exit-site infection of the peritoneal catheter; it is therefore of vital importance to prevent it. This complication has a negative impact on the success of the technique. In spite of this, there are no clear guidelines concerning how to take care of the exit site. The objective of this study was to assess the efficacy of polyhexanide in preventing exit-site infection over a 12-month period.

METHODS

We designed a single-center, prospective, open-labeled, randomized controlled clinical trial with parallel groups. Requirements for participation in the study included implantation of the peritoneal catheter at least six weeks before entering the study and no infectious complications requiring either hospital admission or antibiotic treatment for at least three months before entering into the study. Patients were randomized to be daily cured as follows: Group A: traditional care with saline serum and povidone-iodine; and Group B: polyhexanide solution. Exit sites were evaluated at baseline and every four to six weeks or if any event occurred, according to the Twardowski criteria.

RESULTS

Of the 60 included patients, 46 completed the 12-month follow-up period. Six underwent transplantation, five died and three were transferred to hemodialysis (HD). The treatment was well tolerated, with no side effects nor abandonments due to such effects. Throughout the study period, six patients (20%) undergoing traditional care and only two (6,7%) receiving polyhexanide developed an exit-site infection (p = 0.032). There were a total number of 12 infections; nine occurred in patients following the traditional approach and only three in patients treated with polyhexanide (p = 0.037). The germs responsible for the infections were: S. aureus (six cases), Corynebacterium jeikeium (two cases) and P. aeruginosa (one case) in the saline serum and povidone-iodine group and P. aeruginosa (three cases) in the polyhexanide group. The mean rate of exit-site infection was 1 episode/36.6 patient-months for the traditional care group and 1 episode/102.7 patient-months for the polyhexanide group (p = 0.017). Patients following the traditional treatment required fewer days to get infected than those using polyhexanide (p = 0.033; log rank: 4.2).

CONCLUSIONS

These results show that using polyhexanide is efficient for the prevention of exit-site infections. Patients treated with this product suffer from fewer infections and need more time to become infected. Polyhexanide application is painless, no allergies have been described and it is well tolerated by patients. We therefore propose that it may be used routinely from now on for the care of healthy exit site.

Paricalcitol reduces proteinuria but does not modify peritoneal protein loss in patients on peritoneal dialysis

INTRODUCTION

Paricalcitol, a selective activator of Vitamin D receptors, is successfully used as a treatment of hyperparathyroidism secondary to chronic kidney disease (CKD). In addition, it has been proposed for reducing proteinuria in patients with CKD. Nonetheless, little is known about its effect on peritoneal protein loss in patients on peritoneal dialysis (PD).

OBJECTIVES

To analyse the efficiency of oral paricalcitol in secondary hyperparathyroidism control in PD patients and to verify its effect on urinary and peritoneal effluent protein loss.

MATERIAL AND METHOD

Prospective study with a 12-month follow-up on a cohort of PD patients. Invention consisted of the introduction of paricalcitol for the treatment of secondary hyperparathyroidism. Paricalcitol was dosed according to parathyroid hormone (PTH): 1mg/day for patients with PTH < 500 pg/ml, and 2mg/day for those with higher PTH levels. Epidemiological, clinical and analytical data were analysed.

RESULTS

38 patients (56 ± 19 years, 55% women, 16% diabetics, technique time (14 ± 10 months) were included in the study. Thirty-three of them received 1mg/day of paricalcitol; the rest received 2mg/day. The use of paricalcitol was associated with a PTH decrease of 30.7 ± 6.8% (P<.001) after 12 months of treatment with no changes in calcium (8.82 ± 0.96 vs. 9.02 ± 0.91; P = .153) and phosphate levels (4.78 ± 0.63 vs. 4.93 ± 0.77; P = .693). Patients did not modify treatment concurrent with phosphate binders over the study period, nor did they change the cinacalcet dosage. However, fewer patients needed it by the end of the study. The PTH baseline levels were independent indicators of its decrease (b = 0.689, P = .018), and the rest of the analysed parameters were not affected. Over the study period there was a proteinuria decrease (0.79 ± 0.41 vs. 0.64 ± 0.36 g/day, P = .034) with no changes in renal function (7.2 ± 1.1 vs. 6.3 ± 0.9 ml/min, P =.104). Similarly, no differences were found in in the percentages of patients taking renin-angiotensin system inhibitors (71 vs. 68 %, P = .472) or the doses needed. There was no significant change in peritoneal protein loss (5.8 ± 1.9 vs. 6.0 ± 2.2g/24h, P = .731) nor in serum albumin levels (3.7 ± 1.1 vs. 3.7 ± 1.2g/dl, P = .697).

CONCLUSIONS

The use of oral paricalcitol reduces PTH levels safely and substantially in patients on PD. Their use is associated with a proteinuria decrease and is not linked to a decrease of glomerular filtration rate or changes in the medication that could modify it. We have found no modification in the amount of peritoneal protein loss.

Development of wild barley (Hordeum chilense)-derived DArT markers and their use into genetic and physical mapping

Diversity arrays technology (DArT) genomic libraries were developed from H. chilense accessions to support robust genotyping of this species and a novel crop comprising H. chilense genome (e.g., tritordeums). Over 11,000 DArT clones were obtained using two complexity reduction methods. A subset of 2,209 DArT markers was identified on the arrays containing these clones as polymorphic between parents and segregating in a population of 92 recombinant inbred lines (RIL) developed from the cross between H. chilense accessions H1 and H7. Using the segregation data a high-density map of 1,503 cM was constructed with average inter-bin density of 2.33 cM. A subset of DArT markers was also mapped physically using a set of wheat-H. chilense chromosome addition lines. It allowed the unambiguous assignment of linkage groups to chromosomes. Four segregation distortion regions (SDRs) were found on the chromosomes 2H(ch), 3H(ch) and 5H(ch) in agreement with previous findings in barley. The new map improves the genome coverage of previous H. chilense maps. H. chilense-derived DArT markers will enable further genetic studies in ongoing projects on hybrid wheat, seed carotenoid content improvement or tritordeum breeding program. Besides, the genetic map reported here will be very useful as the basis to develop comparative genomics studies with barley and model species.