The Influence of Aging and Undernutrition on Chemical Contractility and Relaxation of Collagen Fibres in Rats

Chvapil, Miloš; Hruza, Z

doi:10.1159/000210903

Cited by 68 publications

(10 citation statements)

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“…Since these mice had more than twice as high a percentage of fat as was observed in fed normal mice but were fed only two-thirds of the amount consumed by normals (Table 1), the effect of adiposity was clearly separated from that of food intake. Collagen aging was important to measure, because it is accelerated in human diabetes, as well as in an experimentally induced rat diabetes and in ob/ob mice (22)(23)(24), and its rate is known to be retarded by food restriction (25)(26)(27). In the experiments reported here, we confirmed that the rate of collagen aging is greatly accelerated by genetic obesity and retarded by food restriction.…”

Section: Discussionsupporting

confidence: 81%

Effects of food restriction on aging: separation of food intake and adiposity.

Harrison¹,

Archer²,

Astle³

1984

Proc. Natl. Acad. Sci. U.S.A.

178

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Restricted feeding of rodents increases longevity, but its mechanism of action is not understood. We studied the effects of life-long food restriction in genetically obese and normal mice of the same inbred strain in order to distinguish whether the reduction in food intake or the reduction in adiposity (percentage of fatty tissue) was the critical component in retarding the aging process. This was possible because foodrestricted obese (ob/ob) mice maintained a high degree of adiposity. In addition to determining longevities, changes with age were measured in collagen, immune responses, and -renal function. Genetically obese female mice highly congenic with the C57BL/6J inbred strain had substantially reduced longevities and increased rates of aging in tail tendon collagen and thymus-dependent immune responses, but not in urine-concentrating abilities. When their weight was held in a normal range by feeding restricted amounts, longevities were extended almost 50%, although these food-restricted ob/ob mice still had high levels of adiposity, with fat composing about half of their body weights. Their maximum longevities exceeded those of normal C57BL/6J mice and were similar to longevities of equally food-restricted normal mice that were much leaner. Food restricted ob/ob mice had greatly retarded rates of collagen aging, but the rapid losses with age in splenic immune responses were not mitigated. Thus, the extension of life-span by food restriction was inversely related to food consumption and corresponded to the aging rate of collagen. These results suggest that aging is a combination of independent processes; they show that reduced food consumption, not reduced adiposity, is the important component in extending longevity of genetically obese mice.By far the most effective method of increasing longevities in mammals is food restriction (1, 2). Substantial increases have been reported in life-spans of mice and rats whose food intake was restricted by a variety of methods (3-6), and this increase has been attributed to reduced adiposity. These studies have been thought to be relevant to human beings, because there was a continuous, direct relationship between obesity and mortality over a wide range of body weights reported in a very large study by The Society of Actuaries (7). Recently this relationship has been challenged. In surveying relevant longitudinal studies of human beings, Andres found that the lowest mortality rates were shown not by lean people but by individuals 20-30% heavier than their conventionally defined "desirable weights" (8). These conflicting findings may result from the fact that food intake is restricted in the rodent experiments, while the data on human beings, derived from height-to-weight ratios, is a rough estimate of adiposity. Two studies have suggested that adiposity is not correlated with longevity in rats (9, 10); however, the undefined genotypes in one study (9) and the small number examined for this correlation in the other (10) prevented their conclusions from being d...

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Section: Discussionsupporting

confidence: 81%

Effects of food restriction on aging: separation of food intake and adiposity.

Harrison¹,

Archer²,

Astle³

1984

Proc. Natl. Acad. Sci. U.S.A.

178

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“…Chvapil andHruza (1959, 1962) studied the contraction and relaxation of collagen fibres immersed in 2.5 m NaClOj at 25° C when loaded with 50 mg. Their fibres were 60 mm long and 0.15 mm in diameter. They selected two indices of aging: 1. lmtrr the length of the maximally contracted fibre, and 2. li20, fibre length after 120 mm immersion.…”

Section: Methodsmentioning

confidence: 99%

Comparative Studies of Age Tests on Collagen Fibres

M¹,

Everitt²

1967

Gerontology

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“…Collagen fibres from the tail tendon were placed in 10 M urea solution with pH 7 at 25° C for 8, 60, 90, and 120 minutes from the start of contraction (contraction starts usually about 2 min after immersion of the fibre into the solution). For details of the experimental method see Chvapil and Hrtiza (1959).…”

Section: Methodsmentioning

confidence: 99%