Adrenal hyperplasia and adenomas are associated with inhibition of phosphodiesterase 11A in carriers of PDE11A sequence variants that are frequent in the population

Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cyclic AMP (cAMP) signaling. We recently identified patients with micronodular adrenocortical hyperplasia who were carriers of inactivating mutations in the 2q-located phosphodiesterase 11A (PDE11A) gene. We now studied the frequency of two missense substitutions, R804H and R867G, in conserved regions of the enzyme in several sets of normal controls, including 745 individuals enrolled in a longitudinal cohort study, the New York Cancer Project. In the latter, we also screened for the presence of the previously identified PDE11A nonsense mutations. R804H and R867G were frequent among patients with adrenocortical tumors; although statistical significance was not reached, these variants affected significantly enzymatic function in vitro with variable increases in cAMP and/or cyclic guanosine 3',5'-monophosphate levels in HeLa and HEK293 cells. Adrenocortical tissues carrying the R804H mutation showed 2q allelic losses and higher cyclic nucleotide levels and cAMP-responsive element binding protein phosphorylation. We conclude that missense mutations of the PDE11A gene that affect enzymatic activity in vitro are present in the general population; protein-truncating PDE11A mutations may also contribute to a predisposition to other tumors, in addition to their association with adrenocortical hyperplasia. We speculate that PDE11A genetic defects may be associated with adrenal pathology in a wider than previously suspected clinical spectrum that includes asymptomatic individuals.     

Balkan endemic nephropathy and genetic variants of glutathione S-transferases

BACKGROUND: Balkan endemic nephropathy (BEN) is a non-inflammatory, chronic, slow progressing kidney disease, frequently associated with urinary tract tumors. BEN displays familial clustering without an apparent Mendelian inheritance pattern. It has been suggested that environmental toxicants damage urothelial cells in genetically susceptible individuals, which could be the cause of BEN. The metabolism of some substrates that are mediated by glutathione S-transferases (GST), which are polymorphic enzymes, results in nephrotoxic products. To evaluate whether GST genetic heterogeneity could be involved in BEN, we launched a case-control study concerning the association of the most common polymorphic GST variants with BEN. METHODS: DNA was extracted from venous blood samples from 54 unrelated BEN patients and 104 controls inhabiting the same endemic region. GSTM1 and GSTT1 null deletions were identified simultaneously by a triplex polymerase chain reaction (PCR) procedure, and GSTP1 polymorphism was analyzed by PCR-restriction fragment length polymorphism (PCR-RFLP) using Alw261. RESULTS: Carriers of at least one GSTM1 wild type allele (wt-allele) were more prevalent among BEN patients compared to controls (chi2=7.92, p=0.005). The GSTT1 and GSTP1 genotype distributions did not demonstrate statistically significant differences between the groups. The carriers of at least one GSTM1 wt-allele among BEN patients were more prevalent in comparison with controls when the GSTM1 genotypes were combined in pairs with all GSTT1 (chi2=9.52, p=0.023) and GSTP1 (chi2=11.92, p=0.036) genotypes. The combined genotype distributions of the three GST genes studied among BEN patients and controls showed that the frequency of carriers of at least one GSTM1 wt-allele among BEN patients was higher or at least equal to the corresponding frequency among controls in all triple combinations. However, this difference did not reach statistical significance (chi2=14.06, p=0.170). CONCLUSIONS: GSTM1 wt-allele associates with BEN. The significantly lower prevalence of the GSTM1 deletion homozygotes among BEN patients suggests that individuals bearing the GSTM1 null genotype could be better protected.     

Effect of zinc on the activity of Cu/Zn superoxide dismutase and lipid profile in Wistar rats

AIM: The aim of the present study was to analyze the effect of zinc on the activity of Cu/ZnSOD, lipid profile and arterial blood pressure in male Wistar rats. MATERIAL AND METHODS: The study included 53 male Wistar rats with basal weight 190-210 g. The animals were divided into three groups and put on diets with different zinc content. Group I animals (G1, n = 18) were on a diet with zinc content 52 mg/kg, group II animals (G2, n = 18) were on a diet with zinc content 155 mg/kg corresponding to standard food and group III animals (G3, n = 17) received zinc supplementation (236 mg/kg diet). The activity of Cu/ZnSOD was measured in erythrocytes with RANSOD reactive (RANDOX). Zinc content in the laboratory chow and serum concentration of zinc and copper were analyzed by direct flame atomic-absorption spectrophotometry. Lipid profile was determined with reactives of ABX (France). Arterial blood pressure was measured on the rat's tail by an indirect method without anesthesia. RESULTS: Statistically significant decrease (p < 0.05) was found in the activity of Cu/ZnSOD in G1 animals (1993.51 +/- 303.01) compared with G2 animals (2307.07 +/- 240.23). There was a statistically significant increase (p < 0.05) of serum LDL in G3 (1.52 +/- 0.21) compared with G1 animals (1.09 +/- 0.27) and statistically significant increase in the serum triglycerides in G1 animals (1.19 +/- 0.22) compared with G3 animals (0.75 +/- 0.17). CONCLUSIONS: The results indicate that the activity of Cu/ZnSOD changes in relation to zinc diet and this correlates with the change in the arterial blood pressure. Lipid variables also are influenced and zinc supplementation leads to increase in the serum LDL and decrease in the serum triglycerides in Wistar rats.     

Results from the National Strategy for Improvement of Iodine Nutrition in Bulgaria. A study of children and pregnant women living in an iodine-deficient area

Background  

A significant part of Bulgaria is considered an iodine-deficient area. The National Strategy for Prevention and Control of Iodine Deficiency Disorders (IDD) was developed in 1994, and regular surveys undertaken in 2000–2003 indicated a normalization of the iodine supply in the Bulgarian population, including some at-risk population groups (children, schoolchildren, pregnant women). Despite the results achieved, mandating periodic cohort surveys for tracking the elimination of iodine deficiency is necessary.     

Higher brain extracellular potassium is associated with brain metabolic distress and poor outcome after aneurysmal subarachnoid hemorrhage

Introduction

Elevated brain potassium levels ([K⁺]) are associated with neuronal damage in experimental models. The role of brain extracellular [K⁺] in patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH) and its association with hemorrhage load, metabolic dysfunction and outcome has not been studied so far.

Methods

Cerebral microdialysis (CMD) samples from 28 poor grade aSAH patients were analyzed for CMD [K⁺] for 12 consecutive days after ictus, and time-matched to brain metabolic and hemodynamic parameters as well as corresponding plasma [K⁺]. Statistical analysis was performed using a generalized estimating equation with an autoregressive function to handle repeated observations of an individual patient.

Results

CMD [K⁺] did not correlate with plasma [K⁺] (Spearman’s ρ = 0.114, P = 0.109). Higher CMD [K⁺] was associated with the presence of intracerebral hematoma on admission head computed tomography, CMD lactate/pyruvate ratio >40 and CMD lactate >4 mmol/L (P < 0.05). In vitro retrodialysis data suggest that high CMD [K⁺] was of brain cellular origin. Higher CMD [K⁺] was significantly associated with poor 3-month outcome, even after adjusting for age and disease severity (P < 0.01).

Conclusions

The results of this pilot study suggest that brain extracellular [K⁺] may serve as a biomarker for brain tissue injury in poor-grade aSAH patients. Further studies are needed to elucidate the relevance of brain interstitial K⁺ levels in the pathophysiology of secondary brain injury after aSAH.     

Interictal alterations of cytokines and leukocytes in patients with active epilepsy

Background

Involvement of the innate immune system in the pathogenesis of epilepsies has been suggested but possible interactions between the immune system and human epilepsy remain unclear. We analyzed the interictal immuno-phenotype of leukocyte subsets and proinflammatory cytokine profiles in epileptic patients and correlated them with the epilepsy syndrome.

Methods

101 patients with active focal or generalized epilepsy were prospectively included and compared to 36 healthy controls. Immuno-phenotype of leukocyte subsets and cytokines IL-1β, IL-6 and tnfα were measured in peripheral blood. Multivariate analyses were performed to test group differences.

Results

As compared to controls, the patients showed an elevated percentage of monocytes (18.06 ± 7.08% vs. 12.68 ± 4.55%, p < 0.001), NK cells (14.88 ± 7.08% vs. 11.43 ± 5.41%, p = 0.019) and IL-6 concentration (3.33 ± 3.11 pg/ml vs. 1.5 ± 1.36 pg/ml, p = 0.002). This remained true when focal epilepsies or generalized epilepsies were compared separately to controls but only focal epilepsies showed additionally a decrease in B lymphocyts (8.16 ± 3.76% vs. 11.54 ± 4.2%, p < 0.001). Treatment with lamotrigine was associated with a higher percentage of B lymphocytes and valproate with an increased percentage of CD4⁺ T lymphocytes. Therapy with levetiracetam showed a trend towards decreased CD8⁺ T cell counts. No significant differences were seen between focal and generalized epilepsies and between temporal and extratemporal lobe epilepsies.

Conclusion

Patients with active epilepsy revealed interictal alterations of the immune system which varied among specific syndromes and were influenced by antiepileptic drug treatment.