Age-associated increase of thyroid hormone receptor ß gene promoter methylation coexists with decreased gene expression.

PURPOSE: It is not established if healthy aging of the thyroid axis is associated with alterations other than changes in hormone secretion. METHODS: The expression of thyroid hormone receptor ß gene (THRB) was analyzed in peripheral blood mononuclear cells (PBMC) obtained from young, elderly, and long-lived individuals. The interaction between the 3'UTR of TRß1 mRNA and selected miRNAs was measured using pmirGLO reporter vector. Methylation of the THRB CpG island was analyzed using methylation-sensitive restriction/RT-PCR and bisulfite sequencing methods. RESULTS: Old age was associated with a significantly lower amount of total TRß mRNA (p = 0.033) and of TRß1 mRNA (p = 0.02). Older age was also associated with significantly higher methylation of the THRB promoter (restriction/RT-PCR: p = 0.0023, bisulfite sequencing: p = 0.0004). Higher methylation corresponded to a lower expression of the THRB mRNA, but this correlation did not reach the level of significance. miR-26a interacted with two sites in the 3'UTR of the TRß1 mRNA leading to the decrease of the reporter protein activity (p < 0.0001 and p = 0.0005), and miR-496 interacted with one of the two putative binding sites which also decreased the reporter protein activity (p < 0.0001). Analysis of the expression of miR-21, miR-26a, miR-146a, miR-181a, miR-221, and miR-496 showed that the expression of miR-26a was significantly decreased in old subjects (p = 0.017), while the levels of other miRNAs were unaffected. CONCLUSIONS: Age-related decrease of THRB expression in PBMC of elderly and long-lived humans might be, in part, a result of the increased methylation of its promoter, but is unrelated to the activity of the miRNAs analyzed here.

miR-96, miR-145 and miR-9 expression increases, and IGF-1R and FOXO1 expression decreases in peripheral blood mononuclear cells of aging humans.

BACKGROUND: In mammals, the IGF-1 pathway affects the phenotype of aging. Since the function of the immune system is modulated by IGF-1, it is plausible that immunosenescence might in part result from altered control by this pathway. We therefore examined whether the expression of IGF-1R, FOXO1, and FOXO3a in peripheral blood mononuclear cells (PBMC) changes with age and if this might be due to changes in the expression of select miRNAs. METHODS: The expression of IGF-1R, FOXO1, FOXO3a, as well as of miR-9, miR-96, miR-99a, miR-132, miR-145, and miR-182 was examined in PBMC of young (27.8 ± 3.7 years), elderly (65.6 ± 3.4 years), and long-lived (94.0 ± 3.7 years) Polish Caucasians using real-time PCR. mRNA/miRNA interactions were studied in HEK 293 cells using luciferase-expressing pmirGLO reporter vector. RESULTS: The median expression of IGF-1R decreased with age (p < 0.000001), as did the expression of FOXO1 (p < 0.000001), while the expression of FOXO3a remained stable. We also found an age-associated increase of the median expression of miR-96 (p = 0.002), miR-145 (p = 0.024) and miR-9 (p = 0.026), decrease of the expression of miR-99a (p = 0.037), and no changes regarding miR-132 and miR-182. Functional studies revealed that miR-96 and miR-182 interacted with human IGF-1R mRNA, and that miR-145 and miR-132 interacted with human FOXO1 mRNA. CONCLUSIONS: The age-associated higher expression of miR-96 and miR-145 might contribute to the lower expression of IGF-1R while the higher expression of miR-96, miR-145 and miR-9 might contribute to the lower expression of FOXO1 in peripheral blood mononuclear cells of aging humans. Sustained expression/function of FOXO3a but not of the other two genes might be important for the maintenance of the immune system function in these individuals.

Cognitive performance and functional status are the major factors predicting survival of centenarians in Poland.

BACKGROUND: Clinical and biochemical predictors of extreme longevity would be useful in geriatric practice but have still not been clearly defined. METHODS: To identify the best nongenetic predictors of survival in centenarians, we examined 340 individuals aged 100+ years. A detailed questionnaire was completed, and comprehensive geriatric assessment and blood analyses were performed. Survival of study participants was checked annually over the period of 10 years. RESULTS: In the univariate Cox proportional hazards model, a longer survival of centenarians was correlated with a higher adjusted Mini-Mental State Examination (MMSE(adj)) score (p < .000001), higher Activities of Daily Living (ADL) and adjusted Instrumental Activities of Daily Living (IADL(adj)) scores (p < .000001 and p = .00008, respectively), and younger age at the time of testing (p = .005). Blood pressure, lipid profile, and C-reactive protein and hemoglobin concentrations were not associated with survival. Multivariate analysis including age, sex, and the MMSE(adj) and ADL scores showed that both MMSE(adj) and ADL predicted survival (HR = 0.978 per each MMSE(adj) point, 95% CI: 0.964-0.993, p = .004; HR = 0.900 per each ADL point, 95% CI: 0.842-0.962, p = .002, respectively). In multivariate analysis with the ADL score substituted by the IADL(adj) score, the only predictor of survival was MMSE(adj) (HR = 0.973 per each MMSE(adj) point, 95% CI: 0.958-0.988, p = .0006). CONCLUSIONS: Cognitive and functional performances are predictors of survival in centenarians.

Small-molecule hormones: molecular mechanisms of action.

Small-molecule hormones play crucial roles in the development and in the maintenance of an adult mammalian organism. On the molecular level, they regulate a plethora of biological pathways. Part of their actions depends on their transcription-regulating properties, exerted by highly specific nuclear receptors which are hormone-dependent transcription factors. Nuclear hormone receptors interact with coactivators, corepressors, basal transcription factors, and other transcription factors in order to modulate the activity of target genes in a manner that is dependent on tissue, age and developmental and pathophysiological states. The biological effect of this mechanism becomes apparent not earlier than 30-60 minutes after hormonal stimulus. In addition, small-molecule hormones modify the function of the cell by a number of nongenomic mechanisms, involving interaction with proteins localized in the plasma membrane, in the cytoplasm, as well as with proteins localized in other cellular membranes and in nonnuclear cellular compartments. The identity of such proteins is still under investigation; however, it seems that extranuclear fractions of nuclear hormone receptors commonly serve this function. A direct interaction of small-molecule hormones with membrane phospholipids and with mRNA is also postulated. In these mechanisms, the reaction to hormonal stimulus appears within seconds or minutes.

[Adrenal tuberculosis as a cause of primary adrenal insufficiency--case report]. / Gruzlica nadnerczy przyczyna niedoczynnosci kory nadnerczy--opis przypadku.

Adrenal tuberculosis is relatively infrequent cause of primary adrenocortical insufficiency in developed countries. Adrenal involvement is most often the result of hematogenous spread of the pulmonary tuberculosis. Isolated adrenal tuberculosis, especially with enlargement of adrenal glands can cause diagnostic problems and requires differentiation from primary or secondary neoplastic disease. In this paper we present a case of 61-year-old man with several months history of adrenocortical insufficiency without signs of pulmonary tuberculosis. Computed tomography scan revealed asymmetrical mass-like enlargement in adrenal glands. Despite of consecutive investigations, the diagnosis remained uncertain. Because of the possibility of neoplastic process of unknown origin, the patient was qualified for surgical exploration during which both enlarged glands were removed. The diagnosis of tuberculosis was made on microscopic examination.