Polymorphisms of the TNF-alpha and ACE genes, and renal scarring in infants with urinary tract infection.

PURPOSE: Susceptibility to renal scarring is increasingly investigated through polymorphisms of genes regulating inflammation and fibrosis. TNF-alpha and ACE gene polymorphisms have been studied in chronic renal conditions but their role in urinary tract infection and vesicoureteral reflux associated renal scarring is unclear. We investigated the relationship between TNF-alpha A/G and ACE I/D polymorphisms, and renal scarring after urinary tract infection in infants. MATERIALS AND METHODS: ACE I/D and TNF-alpha -308 A/G polymorphisms were investigated with restriction fragment length polymorphism analysis in 39 boys and 25 girls with a first urinary tract infection before age 2 years and in 77 controls. Genotype and allele frequencies were compared among children with urinary tract infection with and without renal scarring, and controls. RESULTS: ACE I/D genotype frequencies were similar among infants with urinary tract infection with and without renal scarring, and controls. However, all 6 children with severe renal scarring and impaired renal function bore a D allele, 5 of which were DD homozygotes. D allele was more common in these severely affected children than in their peers with urinary tract infection and mild or no renal scarring (OR 9.92, 95% CI 1.24-79, p = 0.012), and controls (OR 8.03, 95% CI 1.01-64, p = 0.029). No differences were observed in TNF-alpha A/G genotype frequencies among the 3 groups. Presence of vesicoureteral reflux was not related to phenotypes or allele frequencies. CONCLUSIONS: Our findings suggest that D allele polymorphism of the ACE gene is associated with urinary tract infection related severe renal scarring in young children.

Are mesenchymal stromal cells from children resistant to apoptosis?

OBJECTIVES: Mesenchymal stromal cells (MSC) represent a novel cellular candidate in the field of transplantation and tissue regeneration. Their clinical application requires their in vitro expansion. The aim of this study was to assess the effect of conditions that would favour apoptosis, and of long-term expansion, on the characteristics of MSC from children. MATERIALS AND METHODS: Bone marrow mononuclear cells were cultured for 10 passages (P1-P10). Expression of CD105, CD146, CD95 and apoptosis by 7-amino-actinomycin D staining were evaluated. CFU-F and cell doubling time (DT) were assessed in every passage. Cell-cycle study was performed at P2 and P6. RESULTS: CFU-F decreased from 38 +/- 3.7 at P2 to 9.6 +/- 3.2 per 10 MSC/cm(2) at P10 and DT increased from 1.93 +/- 0.1 (P2) to 6.1 +/- 2.45 days (P10). A low percentage of apoptotic (dead) cells was detected at P2 and this did not change until P10. Cells at P2 were at G(0)/G(1) phase, but in advanced passages more cells were in an active state. Induction of apoptosis (addition of anti-Fas agonist antibody) using standard culture conditions, showed a minor effect on MSC survival. Serum deprivation of MSC (up to 72 h) revealed no substantial apoptotic effect while cells retained their tri-lineage differentiation capacity. CONCLUSIONS: We conclude that MSC from children retain their functional characteristics throughout serial passages and remain stable under conditions that usually cause apoptosis. These features render MSC, especially those of early passages, optimal candidates for use in clinical applications.

Study of oncogenic transformation in ex vivo expanded mesenchymal cells, from paediatric bone marrow.

OBJECTIVES: Mesenchymal stromal cells (MSCs) have attracted considerable interest in both the scientific and clinical fields. In order to obtain a sufficient cell number for application, their in vitro expansion is necessary, but during this process their characteristics may be altered and cells may acquire oncogenic properties. We have investigated properties of MSC that may be related to oncogenesis, a critical parameter that has to be evaluated prior to MSC clinical use. MATERIALS AND METHODS: We studied the expression of p53, p16, RB, H-RAS and human telomerase reverse transcriptase (hTERT) in MSCs from bone marrow of children diagnosed with idiopathic thrombocytopenic purpura (ITP) and autoimmune neutropenia. The same cells were seeded in soft agar to confirm their anchorage dependence and were karyotypically analysed. Finally, MSCs were subcutaneously transplanted into SCID mice and their ectopic osteogenic as well as tumorigenic potential was evaluated. RESULTS: We have shown that MSCs derived from bone marrow of children with ITP and autoimmune neutropenia do not undergo transformation, the cells expressed normal levels of p53, p16, RB and H-RAS. Expression of hTERT was undetectable, chromosome content remained stable, and their anchorage dependence was confirmed. In an in vivo model, when MSCs were subcutaneously transplanted into SCID mice, no tumorigenesis was observed. CONCLUSIONS: These findings suggest that MSCs from bone marrow of children do not have oncogenic properties and, therefore, represent validate candidates for applications in regenerative medicine.

Apolipoprotein E polymorphism is not associated with lipid levels and coronary artery disease in Greek patients with familial hypercholesterolaemia.

Familial hypercholesterolaemia is a genetic disorder characterised by high low-density lipoprotein (LDL) cholesterol concentrations, which frequently gives rise to premature coronary artery disease (CAD). The clinical expression of familial hypercholesterolaemia is highly variable even in patients carrying the same LDL receptor gene mutation. This variability may be due to environmental and other genetic factors. Apolipoprotein E (Apo-E) has been extensively studied for its effects on the phenotype of familial hypercholesterolaemia. In this study we examined the influence of Apo-E genotype on lipid parameters and the incidence of CAD in 93 Greek patients with familial hypercholesterolaemia. Apo-E E2, E3 and E4 allele frequencies were 0.06, 0.86 and 0.09 respectively. The levels of total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, apolipoproteins A and B and lipoprotein alpha did not differ significantly among carriers and non-carriers of the E4 allele. The prevalence of CAD and hypertension did not differ either. Our results suggest that the E4 allele is not associated with lipid levels or with the prevalence of CAD among familial hypercholesterolaemia patients of the Greek population.

FH clinical phenotype in Greek patients with LDL-R defective vs. negative mutations.

BACKGROUND: Familial hypercholesterolaemia (FH) is caused by mutations in the low-density lipoprotein receptor gene and the gene encoding apolipoprotein B-100, affecting one in 500 individuals. METHODS: One hundred and eighty-three Greek FH patients were screened for mutations on the LDLR and ApoB genes. RESULTS: We identified mutations in 67 probands and 11 relatives. Sixteen mutations located in eight different exons and the promoter of the LDLR were discovered. Among them 10 were missense mutations (C6W, S265R, A370T, Q363P, D365E, V408M, A410T, A517T, G528D, G571E), two were nonsense mutations (Q363X and C660X), three were splice defects (2140 + 5G-->A and 2140 + 9C-->T, 1706 - 10G-->A), and one was a nucleotide substitution (- 45delT) on the promoter. None of the subjects carried any apoB mutation. The detection rate of mutations in this study was 43%. From the above mutations, A410T, A519T and the splice site defects 2140 + 9C-->T were detected for the first time in the Greek population. Among them V408M, G528D, C6W and S265R account for 73% of heterozygous FH probands. V408M mutation is more common in Central West, while C6W is more common in Central East. Separating the patients into two groups (receptor defective and receptor negative) we found that the receptor negative group had higher levels of total cholesterol, low-density lipoprotein cholesterol and higher prevalence of tendon xanthomas compared with the receptor-defective group. DISCUSSION: The homogenous molecular basis of familial hypercholesterolaemia in Greece facilitates the application of a DNA diagnostic strategy based on the origin of the patient. The early mutation analysis would add valuable information on the severity of the disease.

FH-Pyrgos: a novel mutation in the promoter (-45delT) of the low-density lipoprotein receptor gene associated with familial hypercholesterolemia.

In a patient with familial hypercholesterolemia (FH), we have identified a new mutation (-45delT) in repeat 3 of the low-density lipoprotein receptor (LDLR) gene promoter. Analysis of a neutral polymorphism in the LDLR mRNA from the patient's white blood cells showed that the expression of one allele was significantly reduced, and cells have only 24% of LDLR activity by binding and uptake of DiI-LDL. Transient transfection studies using a luciferase gene reporter revealed that the -45delT mutation considerably reduces the transcriptional activity of the LDLR promoter and strongly suggest that the mutation is the cause of the FH phenotype.