Oxygen

Publication Title: 
Journal of Cellular Physiology

Various concentrations of oxygen were used to determine the optimum culture medium PO2 for survival and proliferation of attached human and mouse fibroblasts grown from different inoculum sizes. When T-15 flasks were seeded with less than or equal to 2 X 10(4) cells (less than or equal to 1.3 X 10(3) cells/cm2), the highest plating efficiencies and cell yields were obtained with a culture medium PO2 of 40-60 mm Hg.

Author(s): 
Taylor, W. G.
Camalier, R. F.
Sanford, K. K.
Publication Title: 
The EMBO journal

Telomere loss has been proposed as a mechanism for counting cell divisions during aging in normal somatic cells. How such a mitotic clock initiates the intracellular signalling events that culminate in G1 cell cycle arrest and senescence to restrict the lifespan of normal human cells is not known. We investigated the possibility that critically short telomere length activates a DNA damage response pathway involving p53 and p21(WAF1) in aging cells.

Author(s): 
Vaziri, H.
West, M. D.
Allsopp, R. C.
Davison, T. S.
Wu, Y. S.
Arrowsmith, C. H.
Poirier, G. G.
Benchimol, S.
Publication Title: 
Free Radical Research

Previous studies have shown that glucose-6-phosphate dehydrogenase (G6PD)-deficient cells are under increased oxidative stress and undergo premature cellular senescence. The present study demonstrates that G6PD-deficient cells cultured under 3% oxygen concentration had an extended replicative lifespan, as compared with those cultured under atmospheric oxygen level. This was accompanied by a reduction in the number of senescence-associated beta-galactosidase (SA-beta-Gal) positive and morphologically senile cells at comparable population doubling levels (PDL).

Author(s): 
Ho, Hung-Yao
Cheng, Mei-Ling
Cheng, Pei-Fen
Chiu, Daniel Tsun-Yee
Publication Title: 
Aging Cell

Brain aging is associated with a progressive imbalance between antioxidant defenses and intracellular concentrations of reactive oxygen species (ROS) as exemplified by increases in products of lipid peroxidation, protein oxidation, and DNA oxidation. Oxidative conditions cause not only structural damage but also changes in the set points of redox-sensitive signaling processes including the insulin receptor signaling pathway. In the absence of insulin, the otherwise low insulin receptor signaling is strongly enhanced by oxidative conditions.

Author(s): 
Drˆge, Wulf
Schipper, Hyman M.
Publication Title: 
Biogerontology

The replicative lifespan of many cell types is determined by the length of telomeres in the initiating cell population. In 20% oxygen, IMR90 cells have a shorter replicative lifespan compared to that achieved in conditions that lower the levels of oxidative stress. We sought to address the role of telomere dynamics in determining the replicative lifespan of IMR90 cells. We analysed clonal populations cultured in parallel in 3 and 20% oxygen. We observed that, at senescence, telomere length was shorter in 3% oxygen and this was proportional to the lifespan extension.

Author(s): 
Britt-Compton, Bethan
Wyllie, Fiona
Rowson, Jan
Capper, Rebecca
E Jones, Rhiannon
M Baird, Duncan
Publication Title: 
Advances in Experimental Medicine and Biology

During development and aging, vascular remodeling represents a critical adaptive response to modifications in oxygen supply to tissues. Hypoxia inducible factor (HIF) has a crucial role and is modulated by oxygen levels, with an age-dependent response in neonates, adult, and aged people. ROS are generated under hypoxic conditions and the accumulation of free radicals during life reduces the ability of tissues to their removal.

Author(s): 
Zara, S.
Pokorski, M.
Cataldi, A.
Porzionato, A.
De Caro, R.
Antosiewicz, J.
Di Giulio, C.
Publication Title: 
Nature

The naked mole rat (Heterocephalus glaber) is a strictly subterranean, extraordinarily long-lived eusocial mammal. Although it is the size of a mouse, its maximum lifespan exceeds 30 years, making this animal the longest-living rodent. Naked mole rats show negligible senescence, no age-related increase in mortality, and high fecundity until death. In addition to delayed ageing, they are resistant to both spontaneous cancer and experimentally induced tumorigenesis. Naked mole rats pose a challenge to the theories that link ageing, cancer and redox homeostasis.

Author(s): 
Kim, Eun Bae
Fang, Xiaodong
Fushan, Alexey A.
Huang, Zhiyong
Lobanov, Alexei V.
Han, Lijuan
Marino, Stefano M.
Sun, Xiaoqing
Turanov, Anton A.
Yang, Pengcheng
Yim, Sun Hee
Zhao, Xiang
Kasaikina, Marina V.
Stoletzki, Nina
Peng, Chunfang
Polak, Paz
Xiong, Zhiqiang
Kiezun, Adam
Zhu, Yabing
Chen, Yuanxin
Kryukov, Gregory V.
Zhang, Qiang
Peshkin, Leonid
Yang, Lan
Bronson, Roderick T.
Buffenstein, Rochelle
Wang, Bo
Han, Changlei
Li, Qiye
Chen, Li
Zhao, Wei
Sunyaev, Shamil R.
Park, Thomas J.
Zhang, Guojie
Wang, Jun
Gladyshev, Vadim N.
Publication Title: 
Advances in Gerontology = Uspekhi Gerontologii / Rossi?skai?a Akademii?a Nauk, Gerontologicheskoe Obshchestvo

This work was undertaken to study tissue oxygen exchange and oxidative processes in the long-lived individuals who were assumed as the physiologically aging individuals. Oxygen tension was assessed in forearm subcutaneous cellular tissue by means of the polarographic method while performing 10 min oxygen inhalation tests (with spontaneous oxygemogram recording) and a 10 min clamping of vessels. The obtained data served as the tissue oxygen exchange indicator. This approach made us possible to evaluate the oxygen delivery and oxygen uptake.

Author(s): 
Korkushko, O. V.
Ivanov, L. A.
Shatilo, V. B.
Publication Title: 
The EMBO journal

Lifespan of C. elegans is affected by the nervous system; however, the underlying neural integration still remains unclear. In this work, we targeted an antagonistic neural system consisting of low-oxygen sensing BAG neurons and high-oxygen sensing URX neurons. While ablation of BAG neurons increases lifespan of C. elegans, ablation of URX neurons decreases lifespan. Genetic analysis revealed that BAG and URX neurons counterbalance each other via different guanylate cyclases (GCYs) to control lifespan balance.

Author(s): 
Liu, Tiewen
Cai, Dongsheng
Publication Title: 
Journal of Nutritional Science and Vitaminology

Dietary restriction elongates life span by suppressing age-related diseases in experimental animals. It has received a great deal of attention in connection with the relationship between aging, nutrition, and oxidative stress because oxidative injury in several tissues is a prominent feature in the aging process. Although the oxidative stress theory of aging has currently gained popularity, the premise from which this hypothesis was derived is paradoxical because the same oxygen, that supports life in one hand threatens survival and promotes aging in the other.

Author(s): 
Yu, Byung Pal
Lim, Beong Ou
Sugano, Michihiro

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