Cellular telomere length is linked to replicative life span. Telomere repeats are lost in peripheral blood cells in vivo by age, and women show less telomere attrition than men. Previous reports have indicated that telomere length and chromosome-specific telomerelength patterns partly are inherited. The mode of heredity has not been clarified, but a link to the X chromosome was recently suggested. We analyzed peripheral mononuclear cells from 49 unrelated families for telomere length using a real-time PCR method. Short-term cultured Epstein-Barr virus-transformed lymphoblasts from the same individuals (n ؍ 130) were analyzed for ability to maintain telomere length and possible gender-linked inheritance. A statistically significant association between telomere lengths comparing father-son (P ؍ 0.011, n ؍ 20) and father-daughter (P ؍ 0.005, n ؍ 22) pairs was found. However, no correlation was observed between mother-daughter (P ؍ 0.463, n ؍ 23) or mother-son (P ؍ 0.577, n ؍ 18). The father-offspring correlation was highly significant (P < 0.0001), in contrast to mother-offspring (P ؍ 0.361). Epstein-Barr virus cultures demonstrated in most cases telomere preservation inversely related to initial mononuclear cell telomere length with short telomeres displaying the most pronounced elongation. Telomere length is inherited, and evidence for a father-to-offspring heritage of this trait was obtained, whereas in vitro telomere length maintenance was found to be dependent on the initial telomere length.gender S ince the demonstration of an association between telomere length and replicative potential (1-6), telomere biology has been in focus for issues on cellular senescence and immortalization. In human replicating somatic cells, there is an inverse relationship between telomere length and age, in cell cultures as well as at the organism level in vivo, albeit with a large interindividual variation. A strong association exists between critically short telomeres and induction of a senescence program leading to irreversible cell-cycle arrest, although telomere shortening is not an absolute requirement for senescence induction (7). True immortalization requires telomere maintenance, usually executed by the activity of telomerase or more rarely through recombinatorial events, as in ALT (alternative lengthening of telomeres) cells. The telomere reduction observed in normal peripheral mononuclear cells (MNCs) has been estimated to be 14-80 base pairs (bp) per year with some differences between various blood cell types (8-13). Because women have been found to lose fewer repeats per year than men, a gender difference in telomere attrition rate in blood cells has been proposed (10,14,15). Peripheral blood cell telomere length also has been found to be associated with cardiovascular diseases such as hypertension, atherosclerosis, and heart failure (16).Reports on monozygotic and dizygotic twins indicate that mean telomere length as well as chromosome-specific telomerelength patterns are in part inherited (17,18)...
Neuropeptide Y (NPY), a 36-amino-acid peptide widely expressed in the brain is involved in many physiological responses, including hypothalamic control of food intake and cardiovascular homeostasis. NPY mediates its effects through binding to the Y1, Y2 and Y5 G-protein-coupled receptors. Little is known of the role of the Y2 receptor in mediating the different NPY effects. We inactivated the Y2 receptor subtype in mice and found that these mice developed increased body weight, food intake and fat deposition. The null mutant mice showed an attenuated response to leptin administration but a normal response to NPY-induced food intake and intact regulation of re-feeding and body weight after starvation. An absence of the Y2 receptor subtype also affected the basal control of heart rate, but did not influence blood pressure. These findings indicate an inhibitory role for the Y2 receptor subtype in the central regulation of body weight and control of food intake.
OBJECTIVEThe aim of this study was to refine the information regarding the quantitative and spatial dynamics of infiltrating lymphocytes and remaining β-cell volume during the progression of type 1 diabetes in the nonobese diabetic (NOD) mouse model of the disease.RESEARCH DESIGN AND METHODSUsing an ex vivo technique, optical projection tomography (OPT), we quantified and assessed the three-dimensional spatial development and progression of insulitis and β-cell destruction in pancreata from diabetes-prone NOD and non–diabetes-prone congenic NOD.H-2b mice between 3 and 16 weeks of age.RESULTSTogether with results showing the spatial dynamics of the insulitis process, we provide data of β-cell volume distributions down to the level of the individual islets and throughout the pancreas during the development and progression of type 1 diabetes. Our data provide evidence for a compensatory growth potential of the larger insulin+ islets during the later stages of the disease around the time point for development of clinical diabetes. This is in contrast to smaller islets, which appear less resistant to the autoimmune attack. We also provide new information on the spatial dynamics of the insulitis process itself, including its apparently random distribution at onset, the local variations during its further development, and the formation of structures resembling tertiary lymphoid organs at later phases of insulitis progression.CONCLUSIONSOur data provide a powerful tool for phenotypic analysis of genetic and environmental effects on type 1 diabetes etiology as well as for evaluating the potential effect of therapeutic regimes.
Together, these findings demonstrate that the kinetics and dynamics of these key cellular components of autoimmune diabetes can be elucidated using this imaging platform for single cell resolution, non-invasive and repetitive monitoring of the individual islets of Langerhans during the natural development of autoimmune diabetes.
A predicament when assessing the mechanisms underlying the pathogenesis of type-1 diabetes (T1D) has been to maintain simultaneous global and regional information on the loss of insulin-cell mass and the progression of insulitis. We present a procedure for high-resolution 3-D analyses of regions of interest (ROIs), defined on the basis of global assessments of the 3-D distribution, size, and shape of molecularly labeled structures within the full volume of the intact mouse pancreas. We apply a refined protocol for optical projection tomography (OPT)-aided whole pancreas imaging in combination with confocal laser scanning microscopy of site-directed pancreatic microbiopsies. As such, the methodology provides a useful tool for detailed cellular and molecular assessments of the autoimmune insulitis in T1D. It is anticipated that the same approach could be applied to other areas of research where 3-D molecular distributions of both global and regional character is required.
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