AMPK mediates regulation of voltage-gated calcium channels by leptin in isolated neurons from arcuate nucleus.

Neuronal control of the energy homeostasis requires the arcuate nucleus of the hypothalamus. This structure integrates peripheral and central signals concerning the energy state of the body. It comprises two populations of neurons releasing anorexigenic and orexigenic peptides, among others. Both populations are regulated by leptin, an anorexigenic hormone, released by white adipose tissue. Voltage-gated calcium entry is critical to promote neurotransmitter and hormone release. It is already known that calcium channel current is inhibited by leptin in orexigenic neurons. However, fine-tuning details of calcium channel regulation in arcuate nucleus by leptin remain to be elucidated. This work aimed to investigate whether 5' adenosine monophosphate-activated protein kinase (AMPK) underlies the leptin-induced inhibition of calcium channels. By using patch-clamping methods, immunocytochemical, and biochemical reagents, we recorded calcium channel currents in orexigenic neuropeptide Y neurons of the arcuate nucleus of rats. Consistently, leptin inhibition of the calcium channel current was not only prevented by AMPK inhibition with Compound C but also hampered with 5-aminoimidazole-4-carboxamide ribonucleoside. Furthermore, leptin selectively inhibited L-type calcium channel current amplitude without major changes in voltage dependence or current kinetics. These results support for the first time the key role of AMPK in the maintenance and regulation of voltage-gated calcium channels. Together, they advance our understanding of the regulation of calcium channels in the central nervous system and emerging questions concerning food intake and energy balance.NEW & NOTEWORTHY Our results readily support the hypothesis that AMPK is responsible for the maintenance of the calcium current and mediates the fine-tuning modulation of the leptin response. The novelty of these results strengthens the critical role of AMPK in the general energy balance and homeostasis.

AMPK inhibits voltage-gated calcium channel-current in rat chromaffin cells.

Metabolic changes are critical in the regulation of Ca2+ influx in central and peripheral neuroendocrine cells. To study the regulation of L-type Ca2+ channels by AMPK we used biochemical reagents and ATP/glucose-concentration manipulations in rat chromaffin cells. AICAR and Compound-C, at low concentration, significantly induce changes in L-type Ca2+ channel-current amplitude and voltage dependence. Remarkably, an overlasting decrease in the channel-current density can be induced by lowering the intracellular level of ATP. Accordingly, Ca2+ channel-current density gradually diminishes by decreasing the extracellular glucose concentration. By using immunofluorescence, a decrease in the expression of CaV1.2 is observed while decreasing extracellular glucose, suggesting that AMPK reduces the number of functional Ca2+ channels into the plasma membrane. Together, these results support for the first time the dependence of metabolic changes in the maintenance of Ca2+ channel-current by AMPK. They reveal a key step in Ca2+ influx in secretory cells.

Dynamic genetic linkage of intermediate blood pressure phenotypes during postural adaptations in a founder population.

Blood pressure (BP) is a dynamic phenotype that varies rapidly to adjust to changing environmental conditions. Standing upright is a recent evolutionary trait, and genetic factors that influence postural adaptations may contribute to BP variability. We studied the effect of posture on the genetics of BP and intermediate BP phenotypes. We included 384 sib-pairs in 64 sib-ships from families ascertained by early-onset hypertension and dyslipidemia. Blood pressure, three hemodynamic and seven neuroendocrine intermediate BP phenotypes were measured with subjects lying supine and standing upright. The effect of posture on estimates of heritability and genetic covariance was investigated in full pedigrees. Linkage was conducted on 196 candidate genes by sib-pair analyses, and empirical estimates of significance were obtained. A permutation algorithm was implemented to study the postural effect on linkage. ADRA1A, APO, CAST, CORIN, CRHR1, EDNRB, FGF2, GC, GJA1, KCNB2, MMP3, NPY, NR3C2, PLN, TGFBR2, TNFRSF6, and TRHR showed evidence of linkage with any phenotype in the supine position and not upon standing, whereas AKR1B1, CD36, EDNRA, F5, MMP9, PKD2, PON1, PPARG, PPARGC1A, PRKCA, and RET were specifically linked to standing phenotypes. Genetic profiling was undertaken to show genetic interactions among intermediate BP phenotypes and genes specific to each posture. When investigators perform genetic studies exclusively on a single posture, important genetic components of BP are missed. Supine and standing BPs have distinct genetic signatures. Standardized maneuvers influence the results of genetic investigations into BP, thus reflecting its dynamic regulation.

Independent association between inflammatory markers (C-reactive protein, interleukin-6, and TNF-alpha) and essential hypertension.

High blood pressure (HBP) has been associated with elevated C-reactive protein (CRP), a marker of chronic mild inflammation. However, the association between HBP and other inflammatory markers, particularly interleukin 6 (IL-6) and tumour necrosis alpha (TNF-alpha), has not been evaluated in well-controlled studies. We examined the cross-sectional relationship between IL-6, TNF-alpha, and CRP and HBP in a random sample of 196 healthy subjects. All markers were measured in duplicate with high-sensitivity ELISA tests. Three blood pressure (BP) measurments were averaged for the analysis, and subjects with systolic BP >or=140 and/or diastolic BP >or=90 mmHg were considered hypertensive. Log binomial regression was used to estimate multivariate-adjusted prevalence ratios (PR) of HBP. Of the subjects, 40% (79) were hypertensive (mean age: 44 years; range 30-64). After adjustment for age, sex, body mass index, family history of HBP, and the level of the other inflammatory markers, subjects in the second (PR: 3.10, P=0.003), third (PR: 2.32; P=0.031), and fourth quartiles (PR: 2.30; P=0.036) of IL-6 were more than twice as likely to be hypertensive than those in the first quartile. Corresponding PR estimates for TNF-alpha levels were 1.41 (P=0.014) for the second; 1.59 (P=0.001) for the third; and 1.61 (P=0.025) for the fourth quartile. The CRP-HBP association was not statistically significant. Our results suggest that TNF-alpha and IL-6 could be independent risk factors for HBP in apparently healthy subjects. Nevertheless, the temporal relationship between elevated inflammation markers and HBP should be ascertained in prospective cohort studies.

[Type III glycogen storage disease associated with hepatocellular carcinoma]. / Glucogenosis tipo III asociada a carcinoma hepatocelular.

Type III glycogen storage disease is a hereditary disorder with autosomal recessive transmission. It is characterized by accumulation of abnormal glycogen in the liver and, in 80% of patients, in muscle. The liver can also show fibrosis and sometimes cirrhosis. Until 2000, 9 cases of cirrhosis had been published, 3 of which showed associated hepatocarcinoma. We present the case of a 31-year-old woman, diagnosed in childhood with type III glycogen storage disease, who 30 years after onset developed a hepatocellular carcinoma with portal thrombosis in the context of advanced cirrhosis. This is the first case to be reported in the Spanish literature of type III glycogen storage disease associated with hepatocellular carcinoma.

[The Vaccination Program of Andalucía: the identification of evaluation indicators in the framework of quality assurance]. / Programa de Vacunaciones de Andalucía: identificación de indicadores de evaluación en el marco de garantía de calidad.

Quality assurance constitutes a major element in the evaluation of health services and has recently been introduced into our field. From this perspective, we intend to identify indicators for the evaluation the Andalusian Vaccination Programme, following the scheme proposed by Donabedian. A group of experts with different training backgrounds agreed upon the techniques on which the methodology used was based. Panels of experts were formed and the nominal group technique was used to identify criteria and standards. Mail surveys were made in order to select the most relevant standards from a multiple perspective: importance, ease of measurement and intervention capability. The aspects to be evaluated were defined about structure process and result. A total of 175 criteria and standards were identified, 42 related to structure, 68 related to process and 65 to results. The aspects to be evaluated, selected according to the priority technique used, are proposed to be employed systematically. The possibility of using them in the different structural levels of the health services is discussed.

Operational stability to changes in composition of herbicide mixtures fed to a laboratory-scale biobarrier.

The main objective of this work was to evaluate the operational stability of a laboratory-scale aerobic biobarrier designed for the treatment of water contaminated by mixtures of three herbicides frequently found in agricultural runoffs, atrazine, simazine and 2,4-dichlorophenoxyacetic acid (2,4-D). The microbial consortium used to degrade the herbicides was composed by six cultivable bacterial strains, identified as members of the genera Variovorax, Sphingopyxis, Hydrocarboniphaga, Methylobacterium, Pseudomonas and Acinetobacter. The effect caused by a seventh member of the microbial consortium, a ciliated protozoa of the genus Colpoda, on the herbicides biodegradation kinetics, was also evaluated. The biodegradation of five combinations of the herbicides 2,4-D, atrazine and simazine was studied in the biobarrier, operated in steady state continuous culture at different volumetric loading rates. In all cases, removal efficiencies determined by chemical oxygen demand (COD) and HPLC were nearly 100 %. These results, joined to the null accumulation of aromatic byproducts of atrazine and simazine catabolism, show that after 495 days of operation, in the presence of the protozoa, the adaptability of the microbial consortium to changing environmental conditions allowed the complete removal of the mixture of herbicides.