Search results for " aging"
showing 10 items of 584 documents
A free radical theory of frailty.
2018
The free radical theory of ageing provided an intellectual framework for many laboratories working on ageing. However, experimental and clinical evidence showing that high doses of antioxidants do not have an effect on ageing or on age-associated diseases, cast doubts on the validity of this theory. Data from our own laboratory show that oxidative damage does not correlate with age, especially in the geriatric population, but rather with the frailty state. This has led us to postulate the free radical theory of frailty that proposes that oxidative damage is associated with frailty, but not with chronological age itself. Superoxide dismutase deficient mice are more frail than controls. But m…
Toll-like receptor-4 signaling pathway in aorta aging and diseases: “its double nature”
2017
Recent advances in the field of innate immunity have revealed a complex role of innate immune signaling pathways in both tissue homeostasis and disease. Among them, the Toll-like receptor 4 (TLR-4) pathways has been linked to various pathophysiological conditions, such as cardiovascular diseases (CVDs). This has been interrogated by developing multiple laboratory tools that have shown in animal models and clinical conditions, the involvement of the TLR-4 signaling pathway in the pathophysiology of different CVDs, such as atherosclerosis, ischemic heart disease, heart failure, ischemia-reperfusion injury and aorta aneurysm. Among these, aorta aneurysm, a very complex pathological condition w…
The Role of Sirtuin1 in Regulating Endothelial Function, Arterial Remodeling and Vascular Aging
2019
Sirtuin1 (SIRT1), which belongs to a highly conserved family of protein deacetylase, is one of the best-studied sirtuins. SIRT1 is involved in a variety of biological processes, including energy metabolism, cell proliferation and survival, chromatin dynamics, and DNA repair. In the vasculature, SIRT1 is ubiquitously expressed in endothelial cells, smooth muscle cells, and perivascular adipose tissues (PVAT). Endothelial SIRT1 plays a unique role in vasoprotection by regulating a large variety of proteins, including endothelial nitric oxide synthase (eNOS). In endothelial cells, SIRT1 and eNOS regulate each other synergistically through positive feedback mechanisms for the maintenance of end…
Impaired DNA demethylation of C/EBP sites causes premature aging
2018
Changes in DNA methylation are among the best-documented epigenetic alterations accompanying organismal aging. However, whether and how altered DNA methylation is causally involved in aging have remained elusive. GADD45α (growth arrest and DNA damage protein 45A) and ING1 (inhibitor of growth family member 1) are adapter proteins for site-specific demethylation by TET (ten-eleven translocation) methylcytosine dioxygenases. Here we show that Gadd45a/Ing1 double-knockout mice display segmental progeria and phenocopy impaired energy homeostasis and lipodystrophy characteristic of Cebp (CCAAT/enhancer-binding protein) mutants. Correspondingly, GADD45α occupies C/EBPβ/δ-dependent superenhancers …
Metformin decreases progerin expression and alleviates pathological defects of Hutchinson–Gilford progeria syndrome cells
2016
Hutchinson–Gilford progeria syndrome (HGPS) is a rare genetic disorder that causes systemic accelerated aging in children. This syndrome is due to a mutation in the LMNA gene that leads to the production of a truncated and toxic form of lamin A called progerin. Because the balance between the A-type lamins is controlled by the RNA-binding protein SRSF1, we have hypothesized that its inhibition may have therapeutic effects for HGPS. For this purpose, we evaluated the antidiabetic drug metformin and demonstrated that 48 h treatment with 5 mmol/l metformin decreases SRSF1 and progerin expression in mesenchymal stem cells derived from HGPS induced pluripotent stem cells (HGPS MSCs). The effect …
Pathological modelling of pigmentation disorders associated with Hutchinson-Gilford Progeria Syndrome (HGPS) revealed an impaired melanogenesis pathw…
2018
AbstractHutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic disorder that leads to premature aging. In this study, we used induced pluripotent stem cells to investigate the hypopigmentation phenotypes observed in patients with progeria. Accordingly, two iPS cell lines were derived from cells from HGPS patients and differentiated into melanocytes. Measurements of melanin content revealed a lower synthesis of melanin in HGPS melanocytes as compared to non-pathologic cells. Analysis of the melanosome maturation process by electron microscopy revealed a lower percentage of mature, fully pigmented melanosomes. Finally, a functional rescue experiment revealed the direct role of progerin…
Sterol 27-hydroxylase polymorphism significantly associates with shorter telomere, higher cardiovascular and type-2 diabetes risk in obese subjects
2018
Background/objectivesThe pathologic relationship linking obesity and lipid dismetabolism with earlier onset of aging-related disorders, including cardiovascular disease (CVD) and type-2 diabetes (T2D), is not fully elucidate. Chronic inflammatory state, in obese individuals, may accelerate cellular aging. However, leukocyte telomere length (LTL), the cellular biological aging indicator, is elusively linked with obesity. Recent studies indicate that sterol 27-hydroxylase (CYP27A1) is an emerging antiatherogenic enzyme, that, by converting extrahepatic cholesterol to 27-hydroxycholesterol, facilitates cholesterol removal via high-density lipoprotein-cholesterol (HDL-C). We tested the hypothes…
The effects of graded caloric restriction: XII. Comparison of mouse to human impact on cellular senescence in the colon.
2018
Calorie restriction (CR) is an effective strategy to delay the onset and progression of aging phenotypes in a variety of organisms. Several molecular players are involved in the anti-aging effects of CR, but mechanisms of regulation are poorly understood. Cellular senescence—a cellular state of irreversible growth arrest—is considered a basic mechanism of aging. Senescent cells accumulate with age and promote a number of age-related pathologies. Whether environmental conditions such as diet affect the accumulation of cellular senescence with age is still unclear. Here, we show that a number of classical transcriptomic markers of senescent cells are reduced in adult but relatively young mice…
Vascular ageing and endothelial cell senescence: Molecular mechanisms of physiology and diseases
2016
Ageing leads to a progressive deterioration of structure and function of all organs over the time. During this process endothelial cells undergo senescence and manifest significant changes in their properties, resulting in impairment of the vascular functionality and neo-angiogenic capability. This ageing-dependent impairment of endothelial functions is considered a key factor contributing to vascular dysfunctions, which is responsible of several age-related diseases of the vascular system and other organs. Several mechanisms have been described to control ageing-related endothelial cell senescence including microRNAs, mitochondrial dysfunction and micro environmental stressors, such as hyp…
The angiotensin‐(1‐7)/Mas receptor axis protects from endothelial cell senescence via klotho and Nrf2 activation
2019
Endothelial cell senescence is a hallmark of vascular aging that predisposes to vascular disease. We aimed to explore the capacity of the renin-angiotensin system (RAS) heptapeptide angiotensin (Ang)-(1-7) to counteract human endothelial cell senescence and to identify intracellular pathways mediating its potential protective action. In human umbilical vein endothelial cell (HUVEC) cultures, Ang II promoted cell senescence, as revealed by the enhancement in senescence-associated galactosidase (SA-β-gal+) positive staining, total and telomeric DNA damage, adhesion molecule expression, and human mononuclear adhesion to HUVEC monolayers. By activating the G protein-coupled receptor Mas, Ang-(1…