Danuta Zwolińska

Cranioectodermal Dysplasia, Sensenbrenner Syndrome, Is a Ciliopathy Caused by Mutations in the IFT122 Gene

Cranioectodermal dysplasia (CED) is a disorder characterized by craniofacial, skeletal, and ectodermal abnormalities. Most cases reported to date are sporadic, but a few familial cases support an autosomal-recessive inheritance pattern. Aiming at the elucidation of the genetic basis of CED, we collected 13 patients with CED symptoms from 12 independent families. In one family with consanguineous parents two siblings were affected, permitting linkage analysis and homozygosity mapping. This revealed a single region of homozygosity with a significant LOD score (3.57) on chromosome 3q21-3q24. By sequencing candidate genes from this interval we found a homozygous missense mutation in the IFT122 (WDR10) gene that cosegregated with the disease. Examination of IFT122 in our patient cohort revealed one additional homozygous missense change in the patient from a second consanguineous family. In addition, we found compound heterozygosity for a donor splice-site change and a missense change in one sporadic patient. All mutations were absent in 340 control chromosomes. Because IFT122 plays an important role in the assembly and maintenance of eukaryotic cilia, we investigated patient fibroblasts and found significantly reduced frequency and length of primary cilia as compared to controls. Furthermore, we transiently knocked down ift122 in zebrafish embryos and observed the typical phenotype found in other models of ciliopathies. Because not all of our patients harbored mutations in IFT122, CED seems to be genetically heterogeneous. Still, by identifying CED as a ciliary disorder, our study suggests that the causative mutations in the unresolved cases most likely affect primary cilia function too.

Matrix metalloproteinases (MMP-2,9) and their tissue inhibitors (TIMP-1,2) as novel markers of stress response and atherogenesis in children with chronic kidney disease (CKD) on conservative treatment

The system of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) may play a key role in atherogenesis of chronic kidney disease (CKD) patients by its impact on matrix accumulation. Connections with inflammation, stress, or endothelial dysfunction are also probable. However, the data on correlations between these parameters in CKD patients are scarce in adults and absent in children. The aim of our study was to evaluate serum concentrations of MMP-2, MMP-9, TIMP-1, and TIMP-2, as well as their correlations with markers of stress response (Hsp90-α, anti-Hsp60), endothelial dysfunction (sE-selectin), and inflammation (high-sensitivity C-reactive protein) in CKD children treated conservatively. Thirty-seven patients were divided into two groups according to the CKD stage (gr.CKDI, 19 children with CKD stages 2–3; gr.CKDII, 18 subjects with CKD stages 4–5). Twenty-four age-matched healthy subjects served as controls. Serum concentrations of MMP-2, MMP-9, TIMP-1, TIMP-2, Hsp90-α, anti-Hsp60, and sE-selectin were assessed by ELISA. Median values of MMP-2, MMP-9, TIMP-1, and TIMP-2 were significantly higher in all CKD children vs. controls and were increased in patients with CKD stages 4–5 vs. CKD stages 2–3. Hsp90-α, anti-Hsp60, sE-selectin, and glomerular filtration rate predicted the values of MMPs and TIMPs. Chronic kidney disease in children is characterized by MMP/TIMP system dysfunction, aggravated by the progression of renal failure. Correlations between examined parameters, heat shock proteins, and markers of endothelial damage suggest the possibility of MMP/TIMP application as indicators of stress response and atherogenesis in children with CKD on conservative treatment.

Serum VCAM-1, ICAM-1, and L-selectin levels in children and young adults with chronic renal failure.

Children and young adults with chronic renal failure (CRF) present with an impaired immune response. Our aim was to analyze whether leukocyte migration, determined by adhesion molecules, is disturbed in the course of CRF, hemodialysis (HD), and peritoneal dialysis (PD). Soluble (s) VCAM-1, ICAM-1, and L-selectin serum levels were evaluated by ELISA in 15 patients with CRF, 22 patients on cuprophane membrane HD, 24 patients on PD, and in 15 controls. The sVCAM-1 levels in all groups were significantly elevated compared with controls. The levels in HD patients were higher than in CRF patients (P <0.05), while levels in PD patients were higher than in CRF and HD (P <0.001 and P <0.01, respectively). The sICAM-1 concentrations in CRF and PD patients were significantly elevated compared with controls (P <0.001 and P <0.0001, respectively); in PD patients sICAM-1 levels were higher than in HD patients (P <0.001), but there were no differences between other groups. sL-selectin levels were decreased in all groups compared with controls. The levels in HD patients were the lowest and the differences, compared with CRF and PD patients, were significant (P <0.05 and P <0.01, respectively). Children and young adults with CRF and on maintenance dialysis have altered concentrations of soluble adhesion molecules, resulting from either inadequate clearance or disturbed synthesis and release. The differences in sVCAM-1 levels between CRF and both groups of patients on dialysis, as well as the differences in sL-selectin concentrations between HD and CRF patients, indicate that these disturbances are aggravated by maintenance dialysis, particularly HD.

Heat shock proteins in chronic kidney disease

Heat shock proteins (HSP) form a heterogenous, evolutionarily conserved group of molecules with high sequence homology. They mainly act as intracellular chaperones, protecting the protein structure and folding under stress conditions. The extracellular HSP, released in the course of damage or necrosis, play a pivotal role in the innate and adaptive immune responses. They also take part in many pathological processes. The aim of this review is to update the recent developments in the field of HSP in chronic kidney disease (CKD), in regard to three different aspects. The first is the assessment of the role of HSP, either positive or deleterious, in the pathogenesis of CKD and the possibilities to influence its progression. The second is the impact of dialysis, being a potentially modifiable stressor, on HSP and the attempt to assess the value of these proteins as the biocompatibility markers. The last area is that of kidney transplantation and the potential role of HSP in the induction of the immune tolerance in kidney recipients.

Serum Concentration of IL-2, IL-6, TNF-Alpha and Their Soluble Receptors in Children on Maintenance Hemodialysis

In chronic renal failure patients a state of immunodeficiency paradoxically coexists with the activation of immune effector cells, including monocytes and lymphocytes. The activation of these cells leads to the release of cytokines. The aim of this study was to estimate the serum concentrations of IL-2, IL-6, TNF-α and their soluble receptors: IL-2 sRα, IL-6 sR, sTNF RI in children with chronic renal failure and young adults on maintenance hemodialysis (HD). The study included 16 HD patients (11 females, 5 males) aged 11–22 (mean 16.1 ± 3.1) years and a control group of 15 age-matched healthy children. Only the mean concentration of IL-6 was similar in HD patients and the control group. The levels of the other cytokines were significantly higher in patients undergoing HD compared to the healthy subjects. No significant differences were observed between the pre- and post-dialysis values or between the values obtained using various dialyzer membranes. These data suggest that immune cells in HD children are in an activated state and that neither a single dialysis session nor the type of dialyzer membrane has an influence on the cytokines examined.

Osteocalcin as a biochemical marker of bone turnover

SUMMARY: Osteocalcin is a calcium‐binding bone protein whose blood concentrations are correlated with bone synthesis and resorption. the level of blood osteocalcin is determined by several factors. Laboratory monitoring of blood osteocalcin is helpful in patient diagnosis and managment. This study presents the known biosynthesis of osteocalcin and its role as an index of bone turnover.

Matrix metalloproteinases and soluble Fas/FasL system as novel regulators of apoptosis in children and young adults on chronic dialysis

The system of membrane receptor Fas and its ligand FasL compose one of the main pathways triggering apoptosis. However, the role of their soluble forms has not been clarified yet. Although sFasL can be converted from the membrane-bound form by matrix metalloproteinases (MMPs), there are no data on relations between sFas/sFasL, MMPs and their tissue inhibitors (TIMPs) in patients on chronic dialysis—neither children nor adults. The aim of our study was to evaluate serum concentrations of sFas, sFasL, and their potential regulators (MMP-2, MMP-7, MMP-9, TIMP-1, TIMP-2), in children and young adults chronically dialyzed. Twenty-two children on automated peritoneal dialysis (APD), 19 patients on hemodialysis (HD) and 30 controls were examined. Serum concentrations of sFas, sFasL, MMPs and TIMPs were assessed by ELISA. Median values of sFas, sFasL, sFas/sFasL ratio, MMP-2, MMP-7, MMP-9, TIMP-1 and TIMP-2 were significantly elevated in all dialyzed patients vs. controls, the highest values being observed in subjects on HD. A single HD session caused the decrease in values of all parameters to the levels below those seen in children on APD. Regression analysis revealed that MMP-7 and TIMP-1 were the best predictors of sFas and sFasL concentrations. Children and young adults on chronic dialysis are prone to sFas/sFasL system dysfunction, more pronounced in patients on hemodialysis. The correlations between sFas/sFasL and examined enzymes suggest that MMPs and TIMPs take part in the regulation of cell death in the pediatric population on chronic dialysis, triggering both anti- (sFas) and pro-apoptotic (sFasL) mechanisms.

THE HEAT SHOCK PROTEIN PROFILE IN CHILDREN WITH CHRONIC KIDNEY DISEASE

♦ Objectives: Chronic kidney disease (CKD) due to inflammation, lipid disorders, and endothelial dysfunction predisposes to accelerated atherosclerosis. Elevated levels of heat shock proteins (HSPs) and antibodies against them have been described in adults with atherosclerotic lesions and cardiovascular events. However, there are no investigations of these variables in children with CKD treated conservatively or on peritoneal dialysis. Therefore, we decided to evaluate the profile of HSPs and their potential role as markers of atherosclerosis in these groups of patients. ♦ Methods: The study group consisted of 37 children with CKD treated conservatively and 19 children and young adults on automated peritoneal dialysis (APD). The control group comprised 15 age-matched subjects with normal kidney function. HSP-60, HSP-70, HSP-90alpha, anti-HSP-60, anti-HSP-70, sE-selectin, and interleukin (IL)-4 serum concentrations were assessed by ELISA; high-sensitivity C-reactive protein (hs-CRP) serum levels were assessed by nephelometry. Serum lipid profiles (total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, triglycerides) were also estimated. ♦ Results: HSP-90α, anti-HSP-60, and sE-selectin concentrations in the CKD and APD patients were higher than in the controls and were lower in the predialysis subjects than in the children on dialysis. Median values of anti-HSP-70 were higher in the CKD patients than in the control group. Levels of IL-4 were increased in all patients versus controls. Median values of HSP-60 were decreased in the CKD and APD children versus controls. HSP-70 and hs-CRP concentrations were comparable in all groups. ♦ Conclusions: The altered HSP and anti-HSP concentrations may imply that the response to stress conditions in the course of CKD is disturbed in children; APD does not aggravate that dysfunction in a significant way. Relationships between HSPs, lipid profile, and markers of inflammation suggest a possible role of the selected HSPs as markers of atherosclerosis in children with CKD.

Soluble adhesion molecules in children and young adults on chronic hemodialysis

Children on chronic hemodialysis (HD) present with impaired immunity that may result from disturbances in leukocyte migration, caused by changes in expression of adhesion molecules on endothelium and immunocompetent cells. However, it is still not clear whether the type of dialyzer or a single dialysis session influences the concentrations of soluble adhesion molecules in these patients. We evaluated by ELISA serum levels of soluble (s) VCAM-1, ICAM-1, L-selectin, and P-selectin in 22 patients on cuprophane HD (CU), 8 on polysulfone HD (PS), 10 on vitamin E-modified cellulose HD (VE), and 15 controls. In all HD patients, sVCAM-1 levels were elevated compared with controls and were higher in CU than in VE. The sICAM-1 concentrations were increased in VE compared with controls, but remained unchanged in CU and PS. The sL-selectin levels were reduced in all HD patients. The mean values of sP-selectin were comparable in CU, PS, and controls. The lowest levels were observed in VE. In CU patients, sVCAM-1, sICAM-1, and sP-selectin concentrations rose after HD. A single PS session had no impact on adhesion molecules, whereas a VE session increased the level of sVCAM-1. The type of dialysis membrane may change the profile of adhesion molecule concentrations, thus influencing the immune system of a child on HD. The increase in levels of adhesion molecules in the course of a single HD session, which was pronounced in CU and VE patients, suggests poor biocompatibility of these dialyzers.

Perception of health-related quality of life in children with chronic kidney disease by the patients and their caregivers: Multicentre national study results

ObjectiveThe aim of the study was to analyse the health-related quality of life (HRQoL) in Polish children with chronic kidney disease (CKD) dependant on the CKD stage, treatment modality and selected social life elements in families of the patients. Furthermore, potential differences between self-report and parent/proxy reports and the factors influencing them were assessed.MethodsA total of 203 CKD children (on haemodialysis (HD), peritoneal dialysis (PD) and conservative treatment (CT)) and their 388 parent/proxies were enrolled into a cross-sectional national study. The demographic and social data were evaluated. We used the Paediatric Quality of Life Inventory 4.0 Generic Core Scales to assess the HRQoL in children.ResultsHealth-related quality of life scores for all CKD groups were significantly lower in all domains compared with population norms, the lowest one being in the HD group. In CT children, HRQoL did not depend on the CKD stage. Both parents assessed the HRQoL of their children differently depending on their involvement in the care. There are differences between the HRQoL scores of the children and their parents.ConclusionThe HRQoL in children with CKD is lower than in healthy children. This is already observed in the early stages of the disease. The disease itself influences the child’s mental state. Children on HD require special support on account of the lowest demonstrated overall HRQoL. Children’s lower rating of the quality of life observed by their parents may render the patients unmotivated and adversely affect their adjustment to life in later years. It may also create conflicts between the parents and the children.