Beata Łoniewska

AMPD1 gene mutations are associated with obesity and diabetes in Polish patients with cardiovascular diseases

Previous studies showed an association of the common functional polymorphism (C34T, Gln12Stop) in the adenosine monophosphate deaminase-1 (AMPD1) gene with survival in heart failure (HF) and/or coronary artery disease (CAD). The aim of the study was to search for other mutations in selected regions of the AMPD1 gene in Polish CAD and HF patients, and to analyze their associations with obesity and diabetes. Exons 2, 3, 5, and 7 of AMPD1 were scanned for mutations in 97 patients with CAD without HF (CAD+ HF−), 104 patients with HF (HF+), and 200 newborns from North-Western Poland using denaturing high-performance liquid chromatography (DHPLC), polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP), and direct sequencing. Frequencies of AMPD1 C34T mutation, as well as novel A99G, G512A, IVS4-6delT, and C784T sequence alterations, were similar in the three groups, but 860T mutated allele was less frequent in the combined CAD+ HF− and HF+ groups than in the controls (1.7% vs. 4.3%, p = 0.040). Heterozygous 34CT genotype was associated with lower (odds ratio [OR] = 0.32, 95% confidence interval [CI] = 0.13–0.81) and 860AT with higher (OR = 13.7, 95%CI = 1.6–118) prevalence of diabetes or hyperglycemia in relation to wild-type homozygotes. Abdominal obesity was more frequent in 860AT patients than in wild-type homozygotes and 34CT heterozygotes (86% vs. 40% vs. 29%, p < 0.05). Nine genes containing polymorphisms linked with AMPD1 C34T mutation were found in the HapMap database. AMPD1 C34T nonsense mutation is associated with reduced prevalence of diabetes and obesity in patients with CAD or HF, but A860T substitution seems to exert opposite metabolic effects and should always be accounted for in the studies of the AMPD1 genotype.

Sequence variants of chemokine receptor genes and susceptibility to HIV-1 infection

Genetic susceptibility to HIV infection was previously proven to be influenced by some chemokine receptor polymorphisms clustering on chromosome 3p21. Here the influence of 5 genetic variants was studied: Δ32CCR5, G(-2459)ACCR5, G190ACCR2, G744ACX3CR1 and C838TCX3CR1. They were screened in a cohort of 168 HIV-1 positive adults [HIV(+) group] and 151 newborns [control group] from northwestern Poland. PCR-RFLP was performed to screen for the variants (except for A32CCR5 polymorphism, where PCR fragment size was sufficient to identify the alleles) and then electrophoresed on agarose gel to determine fragment size. Distribution of genotypes and alleles was not significantly different between the groups except for theCCR5 polymorphisms, with the A32 allele and the (-2459)ACCR5 allele more frequent among neonates than in the HIV(+) group. No Δ32/Δ32 homozygotes were found in the HIV(+) group, but 16.1% were Δ32/wt heterozygotes. In the control group, 1.3% were Δ32/Δ32 homozygotes and 26.0% were Δ32/wt heterozygotes. Linkage between the chemokine polymorphisms was calculated using the most informative loci for haplotype reconstruction. Haplotypes containing Δ32 CCR5,190GCCR2 and 744ACX3CR1 were found to be significantly more common in the control group. This suggests an association between these haplotypes and resistance to HIV-1 infection.

Common Genetic Variants of the BMP4, BMPR1A, BMPR1B, and ACVR1 Genes, Left Ventricular Mass, and Other Parameters of the Heart in Newborns

The members of the family of bone morphogenetic proteins (BMPs) are important regulators in cardiac development. The present study was designed to evaluate the effect of common genetic variants of BMP-4 and its receptors BMPR1A, BMPR1B, and ACVR1 on left ventricular mass (LVM) and other parameters of the heart and blood pressure in newborns. The study included 210 healthy newborns. Two-dimensional M-mode echocardiography was used to assess LVM between days 3 and 4 after birth. Polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism technique. We found lack of associations between LVM, values of blood pressure, and the BMP4, BMPR1A, BMPR1B, and ACVR1 genotypes. A significant association was observed between the 455C allele of BMP4 and increased left ventricular internal diameter systolic (p=0.004) and between 1650T allele of BMPR1B and lower left atrium diameter (p=0.038). Presence of the 455C allele of BMP4 and the 8474T allele of ACVR1 gene was significantly associated with decreased left ventricular ejection fraction (LVEF) (p=0.0004 and p=0.046, respectively). The 455C allele of BMP4 and the 8474T allele of ACVR1 may play a role as significant predictors for decreased LVEF in newborns.

Possible counter effect in newborns of 1936A>G (I646V) polymorphism in the AKAP10 gene encoding A-kinase-anchoring protein 10.

Objective:Cyclic adenosine monophosphate/protein kinase A (PKA) is important in embryonic development. The human AKAP10 gene is polymorphic: 1936A>G results in changes to a PKA-binding domain and increased targeting to mitochondria. Previous studies found G1936 as ‘deleterious’ in adults, and this study investigates whether this holds true in preterm birth.Study Design:Study group consisted of 80 preterm newborns (PTNs) born before the 38th gestation week. Control group consisted of 123 full-term healthy newborns born after the 37th gestation week with uncomplicated pregnancies. Genomic DNA was extracted from umbilical blood and AKAP10 genotypes were identified by PCR/restriction enzyme.Result:Significant differences in frequencies of 1936A>G genotypes/alleles between both groups were found. PTNs had increased frequency (55%) of AA homozygotes (odds ratio, AA versus AG+GG: 2.63 (95% confidence interval: 1.33 to 5.20), P=0.006) after adjustments: mothers with previous PTNs, smoking, first pregnancy, first delivery and Cesarean section.Conclusion:Results suggest G1936 is preventative factor against preterm birth, in contrast with previously asserted negative effects in adults.

Does prenatal antibiotic therapy compromise the diagnosis of early-onset infection and management of the neonate?

Abstract Aim: To assess the impact of prenatal antibiotic treatment on procalcitonin (PCT) and C-reactive protein (CRP) concentrations in cord blood, and on the rate of positive neonatal blood cultures. Methods: Neonates with early-onset infection (Group A; n=46) were compared with healthy controls (Group B; n=240). We evaluated the relationship between prenatal antibiotic therapy and early-onset infection, and for interactions with antibiotic therapy in the neonate immediately after birth. Results: In the Group A antibiotics were administered significantly more often prenatally and more often to neonates just after birth. The percentage of negative blood cultures in infected neonates was higher when antibiotic treatment was instituted prenatally. Differences in cord blood PCT and CRP concentrations were significant between both groups and were independent of prenatal antibiotic treatment. Streptococcus agalactiae was the most frequent species. Conclusions: Almost one-third of neonates present with early-onset infection in spite of prenatal antibiotic therapy. Cord blood PCT and CRP measurements may be helpful in the diagnosis of infection also in cases when antibiotic therapy was started prenatally. Prenatal antibiotic administration reduced the number of positive blood cultures in neonates with early-onset infection and was associated with a greater rate of antibiotic treatment after birth in neonates without infection.

An age-related decrease in factor V Leiden frequency among Polish subjects.

Factor V Leiden (G1691AFV mutation) is a widely acknowledged risk factor of deep vein thrombosis, including pulmonary embolism as the most serious complication. However, its high prevalence of ∼5% in the Caucasian population might be related to an unknown evolutionary advantage. It might exert a beneficial effect on the carrier, e. g. protecting women from excessive bleeding during labour or allowing increased survival in severe sepsis or with other inflammatory diseases. The aim of our study was to verify or contradict the hypothesis of a favourable association between the A allele (A1691) and longevity in the Polish population. For this purpose, the G1691A mutation was analyzed by PCR-RFLP in 1016 Poles: 400 neonates (187 female and 312 male), 184 healthy adults (129 female and 55 male), and 432 long-lived individuals (age ≥ 95 years: 343 women and 89 men). Frequencies of G1691A carriers and the A1691 allele in long-lived individuals (0.2% and 0.1%, respectively) were significantly lower than in neonates (4.2% and 2.2%, respectively) and adults (3.3% and 1.6%). The frequency of the G1691A factor V Leiden mutation decreased with age, which indicates a shorter survival time among A1691 allele carriers in the Polish population.

The Determination of Procalcitonin Concentration in Early-Onset Neonatal Infection: A Valuable Test Regardless of Prenatal Antibiotic Therapy

The aim of this study was to assess the clinical usefulness of blood procalcitonin (PCT) levels for the diagnosis and therapeutic monitoring of early-onset neonatal sepsis (EONS). PCT as well as C-reactive protein (CRP) levels and white blood cell (WBC) count were measured in venous blood from 57 infected and 72 uninfected neonates. Differences between groups for PCT, CRP, and WBC levels were significant. The threshold value on the receiver operating characteristic curve in the prediction of EONS was 5.33 ng/mL for PCT, 9.3 mg/L for CRP, and 14.9 × 109/L for WBC. There was no effect of antibiotic administered to the mother on PCT, CRP, and WBC levels in neonatal blood sampled before treatment of EONS. Evidently reduced PCT levels are observed after 2 days of treatment. The authors conclude that prenatal antibiotic therapy does not reduce the value of PCT levels in blood for the diagnosis of EONS.

Usefulness of estimation of blood procalcitonin concentration versus C-reactive protein concentration and white blood cell count for therapeutic monitoring of sepsis in neonates.

AIM This study was intended to assess the clinical usefulness of blood procalcitonin (PCT) concentrations for the diagnosis and therapeutic monitoring of nosocomial neonatal sepsis. MATERIAL/METHODS The enrolment criterion was sepsis clinically manifesting after three days of life. PCT concentrations were measured in venous blood from 52 infected and 88 uninfected neonates. The results were interpreted against C-reactive protein (CRP) concentrations and white blood cell counts (WBC). RESULTS Differences between the two groups in PCT and CRP concentrations were highly significant. No significant differences between the groups were noted for WBC. The threshold value on the receiver operator characteristic curve was 2.06 ng/mL for PCT (SE 75%; SP 80.68%; PPV 62.22%; NPV 88.75%; AUC 0.805), 5.0 mg/L for CRP (SE 67.44%; SP 73.68%; PPV 42.02%; NPV 88.89%; AUC 0.801), and 11.9 x109/L for WBC (SE 51.16%; SP 50.68%; PPV 23.16%; NPV 78.13%; AUC 0.484). Procalcitonin concentrations decreased 24 hours after initiation of antibiotic therapy and reverted to the control level after 5-7 days. C-reactive protein concentrations began to decline after two days of antibiotic therapy but were still higher than in the control group after 5-7 days of treatment. No significant changes in WBC during the treatment were observed. CONCLUSIONS Procalcitonin concentrations in blood appear to be of use for the diagnosis and therapeutic monitoring of nosocomial infections in neonates as this parameter demonstrates greater sensitivity and specificity than C-reactive protein. White blood cell counts appear to be of little diagnostic value in the early phase of infection or for therapeutic monitoring.

Genetics of the renin-angiotensin system with respect to cardiac and blood pressure phenotypes in healthy newborn infants.

Introduction: Left ventricular mass (LVM) is a strong predictor of various heart diseases. We examine the association between the G(-6)A AGT, I/D ACE, A1166C AGTR1, T(-344)C CYP 11β2, A538G MR and A10631G REN polymorphisms and LVM and blood pressure in newborn infants. Material and methods: The study included 211 healthy newborn infants. Two-dimensional M-mode echocardiography was used to assess LVM between days 3–4 after birth. Polymorphisms were determined by polymerase chain reaction - restriction fragment length polymorphism (PCR-RLFP). Results: AGTR1 genotype was significantly associated with neonatal systolic blood pressure (≥90 percentile). LVM indexes (LVMIs) were tested for association with genotypes in multivariate analysis. The carriers of the A allele of the AGT polymorphism had significantly higher LVM/body length (BL) values when compared with newborn infants homozygous for the G allele (padjusted=0.03). The higher LVM/BL values were seen in the carriers of the A alleles of the AGTR1 polymorphism (padjusted=0.046). All examined indexes (LVM/body surface area (BSA), LVM/BL, LVM/bodyweight (BW)) were associated with CYP11B polymorphism. The newborn infants homozygous for the T allele had significantly higher values of LVM/BSA, LVM/BL, and LVB/BW compared to non-TT-homozygous neonates (padjusted=0.003; padjusted=0.003; padjusted=0.004 respectively). Conclusion: The AGT, AGTR1, CYP11β polymorphisms are associated with increased LVMIs in newborns. This observation indicates that genetic factors may be modulating LVM at birth.

Epistatic interaction between common AGT G(-6)A (rs5051) and AGTR1 A1166C (rs5186) variants contributes to variation in kidney size at birth.

Low nephron number has been recognised as an important cardiovascular risk factor and recently a strong correlation between renal mass and nephron number has been demonstrated in newborns. The aim of this study was to investigate individual, as well as combined, effects of common variants of genes which encode for major components of the renin-angiotensin system (REN G10601A, AGT G(-6)A, ACE I/D, AGTR1 A1166C) on kidney size in healthy, full-term newborns. A significant additive main effect of the ACE I/D polymorphism, as well as an additive-by-additive interaction between AGT G(-6)A and AGTR1 A1166C variants, were found. The variance attributed to the epistatic effect was 27.9 ml(2)/m(4), which accounted for 73.8% of the interaction variance (37.8 ml(2)/m(4)), 66.4% of the genetic variance (42.0 ml(2)/m(4)) and 4.4% to the total phenotypic variance (628 ml(2)/m(4)). No other statistically significant main or epistatic effects were detected. Our results highlight the importance of considering gene-gene interactions as part of the genetic architecture of congenital nephron number, even when the loci do not show significant single locus effects. Unravelling the genetic determinants of low nephron number, along with early molecular screening, may well help to identify children at risk for cardiovascular disease.