Effect of eplerenone on parathyroid hormone levels in patients with primary hyperparathyroidism: a randomized, double-blind, placebo-controlled trial

ABSTRACT: BACKGROUND: Increasing evidence suggests the bidirectional interplay between parathyroid hormone and aldosterone as an important mechanism behind the increased risk of cardiovascular damage and bone disease observed in primary hyperparathyroidism. Our primary object is to assess the efficacy of the mineralocorticoid receptor-blocker eplerenone to reduce parathyroid hormone secretion in patients with parathyroid hormone excess. Methods/design Overall, 110 adult male and female patients with primary hyperparathyroidism will be randomly assigned to eplerenone (25 mg once daily for 4 weeks and 4 weeks with 50 mg once daily after dose titration] or placebo, over eight weeks. Each participant will undergo detailed clinical assessment, including anthropometric evaluation, 24-h ambulatory arterial blood pressure monitoring, echocardiography, kidney function and detailed laboratory determination of biomarkers of bone metabolism and cardiovascular disease. The study comprises the following exploratory endpoints: mean change from baseline to week eight in (1) parathyroid hormone(1--84) as the primary endpoint and (2) 24-hour systolic and diastolic ambulatory blood pressure levels, NT-pro-BNP, biomarkers of bone metabolism, 24 hours urinary protein/albumin excretion and echocardiographic parameters reflecting systolic and diastolic function as well as cardiac dimensions, as secondary endpoints. DISCUSSION: In view of the reciprocal interaction between aldosterone and parathyroid hormone and the potentially ensuing target organ damage, the EPATH trial is designed to determine whether eplerenone, compared to placebo, will effectively impact on parathyroid hormone secretion and improve cardiovascular and bone health in patients with primary hyperparathyroidism. Trial registration ISRCTN33941607.     

The intracellular quality control system down-regulates the secretion of amyloidogenic apolipoprotein A-I variants: A possible impact on the natural history of the disease

Hereditary systemic amyloidosis caused by apolipoprotein A-I variants is a dominantly inherited disease characterised by fibrillar deposits mainly localized in the kidneys, liver, testis and heart. We have previously shown that the apolipoprotein A-I variant circulates in plasma at lower levels than the wild-type form (Mangione et al., 2001; Obici et al., 2004) thus raising the possibility that the amyloid deposits could sequester the circulating amyloidogenic chain or that the intracellular quality control can catch and capture the misfolded amyloidogenic chain before the secretion. In this study we have measured plasma levels of the wild-type and the variant Leu75Pro apolipoprotein A-I in two young heterozygous carriers in which tissue amyloid deposition was still absent. In both cases, the mutant was present at significantly lower levels than the wild-type form, thus indicating that the low plasma concentration of the apolipoprotein A-I variant is not a consequence of the protein entrapment in the amyloid deposits. In order to explore the cell secretion of amyloidogenic apolipoprotein A-I variants, we have studied COS-7 cells expressing either wild-type apolipoprotein A-I or two amyloidogenic mutants: Leu75Pro and Leu174Ser. Quantification of intracellular and extracellular apolipoprotein A-I alongside the intra-cytoplasmatic localization indicates that, unlike the wild-type protein, both variants are retained within the cells and mainly accumulate in the endoplasmic reticulum. The low plasma concentration of amyloidogenic apolipoprotein A-I may therefore be ascribed to the activity of the intracellular quality control that represents a first line of defence against the secretion of pathogenic variants.     

Association of immunoglobulin GM allotypes with longevity in long-living individuals from Southern Italy

Background

The aim of this study was to analyse the role of GM allotypes, i.e. the hereditary antigenic determinants expressed on immunoglobulin polypeptide chains, in the attainment of longevity. The role played by immunoglobulin allotypes in the control of immune responses is well known as well as the role of an efficient immune response in longevity achievement. So, it is conceivable that particular GM allotypes may contribute to the generation of an efficient immune response that supports successful ageing, hence longevity.

Methods

In order to show if GM allotypes play a role in the achievement of longevity, we typed the DNA of 95 Long-living individuals (LLIs) and 96 young control individuals (YCs) from South Italy for GM3/17 and GM23+/? alleles.

Results

To demonstrate the role of GM allotypes in the attainment of longevity we compared genotype and allele frequencies of GM allotypes between LLIs and YCs. A global chi-square test (3?×?2) shows that the distribution of genotypes at the GM 3/17 locus is highly significantly different in LLIs from that observed in YCs (p?<?0.0001). The 2?×?2 chi-square test shows that the carriers of the GM3 allele contribute to this highly significant difference. Accordingly, GM3 allele is significantly overrepresented in LLIs. No significant differences were instead observed regarding GM23 allele.

Conclusion

These preliminary results show that GM3 allotype is significantly overrepresented in LLIs. To best of our knowledge, this is the first study performed to assess the role of GM allotypes in longevity. So, it should be necessary to verify the data in a larger sample of individuals to confirm GM role in the attainment of longevity.

     

Nanomolar melatonin enhances nNOS expression and controls HaCaT-cells bioenergetics

A novel role of melatonin was unveiled, using immortalized human keratinocyte cells (HaCaT) as a model system. Within a time window compatible with its circadian rhythm, melatonin at nanomolar concentration raised both the expression level of the neuronal nitric oxide synthase mRNA and the nitric oxide oxidation products, nitrite and nitrate. On the same time scale, a depression of the mitochondrial membrane potential was detected together with a decrease of the oxidative phosphorylation efficiency, compensated by glycolysis as testified by an increased production of lactate. The melatonin concentration, ～ nmolar, inducing the bioenergetic effects and their time dependence, both suggest that the observed nitric oxide-induced mitochondrial changes might play a role in the metabolic pathways characterizing the circadian melatonin chemistry.     

Mitigation measures for pandemic influenza in Italy: an individual based model considering different scenarios

Background

Individual-based models can provide the most reliable estimates of the spread of infectious diseases. In the present study, we evaluated the diffusion of pandemic influenza in Italy and the impact of various control measures, coupling a global SEIR model for importation of cases with an individual based model (IBM) describing the Italian epidemic.

Methodology/Principal Findings

We co-located the Italian population (57 million inhabitants) to households, schools and workplaces and we assigned travel destinations to match the 2001 census data. We considered different R₀ values (1.4; 1.7; 2), evaluating the impact of control measures (vaccination, antiviral prophylaxis -AVP-, international air travel restrictions and increased social distancing). The administration of two vaccine doses was considered, assuming that first dose would be administered 1-6 months after the first world case, and different values for vaccine effectiveness (VE). With no interventions, importation would occur 37–77 days after the first world case. Air travel restrictions would delay the importation of the pandemic by 7–37 days. With an R₀ of 1.4 or 1.7, the use of combined measures would reduce clinical attack rates (AR) from 21–31% to 0.3–4%. Assuming an R₀ of 2, the AR would decrease from 38% to 8%, yet only if vaccination were started within 2 months of the first world case, in combination with a 90% reduction in international air traffic, closure of schools/workplaces for 4 weeks and AVP of household and school/work close contacts of clinical cases. Varying VE would not substantially affect the results.

Conclusions

This IBM, which is based on country-specific demographic data, could be suitable for the real-time evaluation of measures to be undertaken in the event of the emergence of a new pandemic influenza virus. All preventive measures considered should be implemented to mitigate the pandemic.     

AHR Over-Expression in Papillary Thyroid Carcinoma: Clinical and Molecular Assessments in a Series of Italian Acromegalic Patients with a Long-Term Follow-Up

Aim

Acromegaly reportedly carries an increased risk of malignant and benign thyroid tumors, with a prevalence of thyroid cancer of around 3–7%. Germline mutations in the aryl-hydrocarbon receptor (AHR) interacting protein (AIP) have been identified in familial forms of acromegaly. The molecular and endocrine relationships between follicular thyroid growth and GH-secreting pituitary adenoma have yet to be fully established. Our aim was to study the prevalence of differentiated thyroid cancer (DTC) in acromegaly, focusing on the role of genetic events responsible for the onset of thyroid cancer.

Methods

Germline mutations in the AIP gene were assessed in all patients; BRAF and H-N-K RAS status was analyzed by direct sequencing in thyroid specimens, while immunohistochemistry was used to analyze the protein expression of AIP and AHR. A set of PTCs unrelated to acromegaly was also studied.

Results

12 DTCs (10 papillary and 2 follicular carcinomas) were identified in a cohort of 113 acromegalic patients. No differences in GH/IGF-1 levels or disease activity emerged between patients with and without DTC, but the former were older and more often female. BRAF V600E was found in 70% of the papillary thyroid cancers; there were no RAS mutations. AIP protein expression was similar in neoplastic and normal cells, while AHR protein was expressed more in PTCs carrying BRAF mutations than in normal tissue, irrespective of acromegaly status.

Conclusions

The prevalence of DTC in acromegaly is around 11% and endocrinologists should bear this in mind, especially when examining elderly female patients with uninodular goiter. The DTC risk does not seem to correlate with GH/IGF-1 levels, while it may be associated with BRAF mutations and AHR over-expression. Genetic or epigenetic events probably play a part in promoting thyroid carcinoma.     

Memory CD8+ T cells require CD28 costimulation

CD8(+) T cells are a critical component of the adaptive immune response against infections and tumors. A current paradigm in immunology is that naive CD8(+) T cells require CD28 costimulation, whereas memory CD8(+) T cells do not. We show here, however, that during viral infections of mice, costimulation is required in vivo for the reactivation of memory CD8(+) T cells. In the absence of CD28 costimulation, secondary CD8(+) T cell responses are greatly reduced and this impairs viral clearance. The failure of CD8(+) T cells to expand in the absence of CD28 costimulation is CD4(+) T cell help independent and is accompanied by a failure to down-regulate Bcl-2 and by cell cycle arrest. This requirement for CD28 costimulation was shown in both influenza A and HSV infections. Thus, contrary to current dogma, memory CD8(+) T cells require CD28 costimulation to generate maximal secondary responses against pathogens. Importantly, this CD28 requirement was shown in the context of real infections were multiple other cytokines and costimulators may be up-regulated. Our findings have important implications for pathogens, such as HIV and measles virus, and tumors that evade the immune response by failing to provide CD28 costimulation. These findings also raise questions about the efficacy of CD8(+) T cell-based vaccines against such pathogens and tumors.