Publications

Heredity and changes in hormones and metabolic rates with short-term training

The purpose of this experiment was to assess the effects of a 22-day training program on resting metabolic rate (RMR), thermic effect of a meal (TEM), and associated hormonal changes. Six pairs of male monozygotic twins were submitted to a 22-day ergocycle exercise program designed to induce a deficit in energy balance of 4.2 MJ per day. RMR and TEM after a 4.2-MJ meal challenge were measured before and after training. Results indicated that RMR and TEM did not change significantly, although a large variation in response between twin pairs was observed. Moreover, training reduced (P less than 0.05) basal and postprandial insulin response, plasma thyroid hormones triiodothyronine (T3), thyroxine (T4), and FT4 (P less than 0.05). Absolute changes in RMR and TEM exhibited significant within-pair resemblance in response, with intraclass correlations reaching r = 0.81 (P less than 0.05) and r = 0.72 (P less than 0.05), respectively. Changes in T4 and FT4 also exhibited moderate within-pair resemblance (0.42 less than or equal to r less than or equal to 0.71). These results suggest that short-term exercise training does not modify RMR and TEM but can significantly decrease plasma levels of insulin and thyroid hormones. Moreover, the similarity of response within twin pairs suggests that heredity plays a role in determining RMR, TEM, and thyroid hormone adaptation to exercise training generating a negative energy balance.

Phosphoinositide cycle gene polymorphisms affect the plasma lipid profile in the Quebec Family Study

Background. The small, dense LDL phenotype is associated with an increased cardiovascular disease risk. A genome-wide scan performed on 236 nuclear families of the Quebec Family Study (QFS) revealed a QTL for LDL-peak particle size (LDL-PPD) on the 17q21 region. Three positional candidates were identified in this region according to their implication in the phosphoinositide (PI) cycle: the myotubularin-related protein 4 (MTMR4), the phospholipase C, delta 3 (PLCD3), and the diacylglycerol kinase E (DGKE) genes. Objectives. To test the association between MTMR4, PLCD3, and DGKE gene polymorphisms, LDL-PPD and plasma lipid parameters. Methods. Analyses were performed on 680 subjects of QFS. LDL-PPD was measured by gradient gel electrophoresis on non-denaturating 2–16% polyacrylamide gradient gels. Direct sequencing was performed to identify genetic variations within these genes. Results. The c.-754G>C, c.183G>A, and c.579C>A DGKE SNPs were significantly associated with higher plasma triglyceride levels (p =0.029, p =0.008, p =0.001, respectively). The c.508C>G and c.890T>G MTMR4 polymorphisms were associated with plasma total-cholesterol concentrations (p =0.02, p =0.02, respectively), while no association was observed with PLCD3 gene polymorphisms. Conclusion. The c.579C>A DGKE gene polymorphism is associated with plasma triglyceride levels, while MTMR4 SNPs seem to predict variations in plasma cholesterol levels.

Adipose tissue metabolism and obesity.

No abstract is provided for this article.

Compléments : Body Composition, Cardiorespiratory Fitness, and Low-Grade Inflammation in Middle-Aged Men and Women

No abstract is provided for this article.

Evidence of a quantitative trait locus for energy and macronutrient intakes on chromosome 3q27.3: the Québec Family Study

Background: Little is known about the genes influencing dietary energy and nutrient intakes, despite evidence that these intakes are influenced by genetic factors. Objective: We aimed to identify, by using a genome-wide linkage analysis, chromosomal regions harboring genes that affect energy and macronutrient intakes. Design: Energy, carbohydrate, lipid, and protein intakes were assessed in 836 subjects from 217 families by using a 3-d dietary record. A total of 443 markers were genotyped and tested for linkage; age- and sex-adjusted energy and macronutrient intakes were expressed in grams and as percentages of total energy intake. Regression-based (Haseman-Elston) and variance-component (MERLIN) methods were applied to test for linkage with dietary data. A maximum of 454 sibpairs from 217 nuclear families were available for analysis. Results: The genome scan provided suggestive evidence (P ≤ 0.0023) for the presence of 6 quantitative trait linkages influencing total caloric and macronutrient intakes in the Québec Family Study. Of these, multiple linkages were found on chromosome 3q27.3, in a region harboring the adiponectin gene, at marker D3S1262 for energy [logarithm of odds (LOD): 2.24], carbohydrate (LOD: 2.00), and lipid (LOD: 1.65) intakes. The peak linkages for carbohydrate, lipid, and protein intakes were found on chromosomes 1p32.2 (LOD: 2.39), 1p35.2 (LOD: 2.41), and 10p15.3 (LOD: 2.72), respectively. The linkage results remained significant after adjustment for body mass index, which suggested that the genes underlying these quantitative trait linkages influence dietary intake independent of body size. Conclusion: The linkage on chromosome 3q27.3 with energy, lipid, and carbohydrate intakes suggests that this region of the genome may harbor genes that influence energy and macronutrient intakes in humans.

Familial aggregation ofV˙<scp>o</scp> _{2 max} response to exercise training: results from the HERITAGE Family Study

The aim of this study was to test the hypothesis that individual differences in the response of maximal O 2 uptake (V˙o 2 max ) to a standardized training program are characterized by familial aggregation. A total of 481 sedentary adult Caucasians from 98 two-generation families was exercise trained for 20 wk and was tested for V˙o 2 max on a cycle ergometer twice before and twice after the training program. The mean increase inV˙o 2 max reached ∼400 ml/min, but there was considerable heterogeneity in responsiveness, with some individuals experiencing little or no gain, whereas others gained &gt;1.0 l/min. An ANOVA revealed that there was 2.5 times more variance between families than within families in theV˙o 2 max response variance. With the use of a model-fitting procedure, the most parsimonious models yielded a maximal heritability estimate of 47% for the V˙o 2 max response, which was adjusted for age and sex with a maternal transmission of 28% in one of the models. We conclude that the trainability ofV˙o 2 max is highly familial and includes a significant genetic component.

Physical activity, fitness and atherosclerosis.

Heredity and overfeeding-induced changes in submaximal exercise VO2

The present study investigated the role of heredity in determining changes in the energy cost of submaximal exercise in response to short-term overfeeding. Six pairs of monozygotic twins were subjected to a 1,000 kcal/day surplus for 22 days with careful experimental controls over food intake and physical activities. O2 consumption (VO2) was measured during a submaximal treadmill exercise test 165 min postprandially before and the morning after the overfeeding protocol. As expected, overfeeding induced significant increases in body weight and fat mass. No significant increase in mean exercise VO2 was observed after overfeeding. However, the interindividual variation in overfeeding-induced changes in exercise VO2 was large and not randomly distributed. When comparing intrapair variance for changes in exercise VO2 to interpair variance, a moderate to high within-pair resemblance in response, i.e., a genotype-overfeeding interaction, was observed. Changes in exercise VO2 were positively correlated with those in postexercise levels of blood catecholamines, particularly epinephrine. A negative correlation was found between changes in exercise VO2 and body fat gain. These results are consistent with the concept of a role for the sympathoadrenal system in the regulation of adaptive thermogenesis and the predisposition to store fat. Moreover, these data suggest that the sensitivity to adapt in exercise energy expenditure after overfeeding is inherited to a significant extent.

Metabolic heterogeneity associated with high plasma triglyceride or low HDL cholesterol levels in men.

To further understand the factors involved in the regulation of high plasma triglyceride (TG) or low plasma high density lipoprotein cholesterol (HDL-C) levels, three groups of male subjects (normal TG with low HDL-C levels, high TG with normal HDL-C levels, and high TG with low HDL-C levels) were compared with a sample of normolipemic men with normal TG and HDL-C plasma levels. Mean age was 34 years (range, 20-42 years), and none of the subjects had plasma TG levels > 4.0 mmol/l or familial hypercholesterolemia. Both groups of subjects with high TG levels had a higher body mass index, waist circumference, waist-to-hip circumferences ratio, and a higher ratio of abdominal to femoral adipose tissue areas as measured by computed tomography when compared with normolipemic control subjects. However, during an oral glucose tolerance test only high TG-low HDL-C men had fasting hyperinsulinemia and higher plasma insulin levels compared with normolipemic subjects. In addition, the high TG-low HDL-C group showed reduced HDL apoprotein (apo) A-I levels and a low HDL2-C/HDL3-C ratio. These changes were observed along with a nonsignificant trend for a lower plasma postheparin lipoprotein lipase activity. However, among subjects with high TG and normal HDL-C levels, no evidence of insulin resistance or of a reduction in postheparin lipoprotein lipase activity was observed, suggesting that the high plasma TG levels could be attributed to an increased production of apo B-containing lipoproteins, as high plasma apo B and low density lipoprotein (LDL)-apo B levels were observed in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Medizinische Probleme des Schulsports

No abstract is provided for this article.

Association of sleep duration with type 2 diabetes and impaired glucose tolerance

No abstract is provided for this article.

Body composition in adopted and biological siblings.

Body density through underwater weighing and 6 skinfolds (triceps, biceps, subscapular, suprailiac, abdominal and medial calf) were measured in 871 biological and adopted siblings of French descent from the greater Quebec city area. These individuals belonged to 49 sibships of adopted sibs, 71 sibships of unrelated individuals living together including adoptees, 35 «sibships» of first degree cousins, 229 sibships of biological brothers and sisters, 66 sibships of DZ twins and 83 sibships of MZ twins. Age of subjects ranged from 8 to 26 years. Age and sex accounted from 14% to 48% of the variance in body composition measurements, with the exception of fat free weight (71%). Residual scores of age and sex were submitted to analysis of variance and correlation analysis. The ratio of the between sibships to the within sibship means of squares reached significance (p ^ .05) for almost all measurements in the MZ, DZ, biological and cousin sibships, for the skinfolds but not for body density, fat free weight and the ratio of subcutaneous fat to total fat mass in the unrelated sibships, and for none of the measurements in the adoptive sibships. Interclass correlations could be computed in a maximum of 80 pairs of adopted sibs, 120 pairs of unrelated sibs, 95 pairs of cousins, 370 pairs of biological sibs, 69 pairs of DZ twins and 87 pairs of MZ twins. None of the coefficients reached 0.20 (p < 0.05) in the pairs of adopted or unrelated sibs. On the other hand, correlations were often significant in the pairs of cousins, particularly for the skinfold measurements. The same coefficients were generally significant and increasing from the pairs of brothers and sisters to the pairs of DZ twins and MZ twins. This pattern was particularly clear for several individual skinfolds, the extremity and the trunk skinfolds, the ratio of extremity to trunk subcutaneous fat and fat free weight. Genetic effects reaching about 0.40 and above were found for measurements of subcutaneous fat, fat distribution, body density and fat free weight. Twin data yielded higher and often unrealistic estimates of heritability probably because of the differential effects of the common environment in MZ and DZ pairs. Skinfold measurements, body density obtained through underwater weighing and fat free mass derived from the latter are generally used as indicators of body composition in humans (Malina, 1980). Several investigators have studied skinfold measurements in biologically related brothers and sisters (Howells, 1966; Garn et al. 1975; Mueller, 1978; Mueller and Malina, 1980; Bouchard, 1980; Savard et al. 1983). Others have considered skinfold data in pairs of dizygotic and monozygotic twins living 1Physical Activity Sciences Laboratory, Laval University, Quebec, Canada G1K 7P4. Human Biology, February 1985, Vol. 57, No. 1, pp. 61-75 © Wayne State University Press, 1985 This content downloaded from 157.55.39.144 on Wed, 07 Sep 2016 04:31:57 UTC All use subject to http://about.jstor.org/terms 62 Claude Bouchard et al. together (Osborne and DeGeorge, 1959; Brook et al. 1975; Hawk and Brook, 1979), but only Garn and co-workers (1979) have reported such data in pairs of genetically unrelated siblings living together. On the other hand, the studies cited above have used a maximum of four skinfold measurements, with the exception of Savard et al. (1983), who reported on six sites. Moreover, the relationship between subcutaneous fat and total body fat is not a simple one, as it is affected by age, sex and total fat among several factors (Lohman, 1981). To the best of our knowledge, no studies have been published about body density and fat free weight in biological and unrelated siblings. Therefore, the purpose of this report is to analyse the resemblance in unrelated and biological sibships and the covariation in pairs of sibs of various kinds for six skinfold measurements, subcutaneous fat distribution, body density, fat free weight and a ratio of subcutaneous fat to total fat mass. Material and Methods

Proteomic profiling platforms head to head: Leveraging genetics and clinical traits to compare aptamer- and antibody-based methods

High-throughput proteomic profiling using antibody or aptamer-based affinity reagents is used increasingly in human studies. However, direct analyses to address the relative strengths and weaknesses of these platforms are lacking. We assessed findings from the SomaScan1.3K ( N = 1301 reagents), the SomaScan5K platform ( N = 4979 reagents), and the Olink Explore ( N = 1472 reagents) profiling techniques in 568 adults from the Jackson Heart Study and 219 participants in the HERITAGE Family Study across four performance domains: precision, accuracy, analytic breadth, and phenotypic associations leveraging detailed clinical phenotyping and genetic data. Across these studies, we show evidence supporting more reliable protein target specificity and a higher number of phenotypic associations for the Olink platform, while the Soma platforms benefit from greater measurement precision and analytic breadth across the proteome.

Abstract P131: Racial Differences in the Response of Cardiorespiratory Fitness to Aerobic Exercise Training in Caucasian and African American Postmenopausal Women

Introduction: African American (AA) women have an elevated risk of cardiovascular disease and have been reported to have lower cardiorespiratory fitness compared to Caucasian Americans (CA) women. ...

Current understanding of the etiology of obesity: genetic and nongenetic factors

Four types of human obesities are defined by topography of fat deposition. The focus of the paper is on the genetic determinants and the nongenetic correlates of the first type, which is commonly defined as excess weight-for-height or excess body fat without a particular concentration of fat in a given area of the body. The heritability of fat mass or percent body fat derived from underwater-weighing assessment of body density reaches ∼25% of the age- and gender-adjusted pheno-typic variance. The within-identical-twin-pair resemblance in the response to a standardized overfeeding protocol emphasizes the importance of the genotype in determining individual differences in body weight and body composition. In this regard, the proneness to store energy primarily as fat or as lean tissue is a major determinant of the response to a caloric surplus.

Negative energy balance with exercise in identical twins: plasma glucose and insulin responses

The effects of long-term (93 days) negative energy balance on plasma glucose and insulin were investigated by means of exercise with constant energy intake in seven pairs of young sedentary male identical twins. Results showed a significant decrease in fasting (-24%, P &lt; 0.02) and postprandial insulin (-16%, P &lt; 0.05). Fasting and postprandial plasma glucose and glucagon were not modified. Mean glucose disposal rate measured during a euglycemic-hyperinsulinemic clamp performed in five twin pairs was increased by 34% (P = 0.13). No significant intrapair similarity was found for the responses of fasting and postprandial insulin levels and of glucose disposal rate. Changes in glucose disposal rate were significantly greater in high compared with low losers for computerized tomography-measured abdominal visceral fat (3.0 +/- 1.1 vs. 0.3 +/- 0.5 mg x kg(-1) x min(-1), P &lt; 0.05) despite similar losses in total body fat. We conclude that 1) a long-term negative energy balance generated by exercise training significantly reduces plasma insulin levels, whereas insulin sensitivity tends to be improved; 2) training-induced changes in insulin sensitivity are associated with changes in abdominal visceral fat; and 3) data from this experiment conducted with a small number of twin pairs suggest that the genotype does not seem to be a major determinant of the changes in insulin levels and sensitivity brought about by negative energy balance with exercise.

Cross-trait familial resemblance for body fat and blood pressure: familial correlations in the Québec Family Study.

Plasma protein patterns as comprehensive indicators of health

No abstract is provided for this article.