Angiogenin gene-race interaction for resting and exercise BP phenotypes: the HERITAGE Family Study

We examined the association between an angiogenin gene polymorphism and blood pressure (BP) at rest and in response to acute exercise before and after a 20-wk endurance-training program. Subjects were 737 normotensive and borderline hypertensive subjects (257 black and 480 white). The polymorphism was detected by PCR and digestion with AvaII, yielding an allele of 253 bp or a rare allele of 194 + 59 bp. Resting and exercise [50 W; 60, 80, and 100% of maximal O2 consumption (VO2 max)] systolic (SBP) and diastolic BP were determined before and after training. Among blacks, adjusted SBP in the sedentary state was significantly lower in carriers of the rare allele at rest and exercise intensities of 60, 80, and 100% of VO2 max. In the trained state, carriers of the rare allele had a significantly (P < 0.05) lower SBP than did noncarriers at rest and at 80 and 100% of VO2 max. The genotypic effect observed among blacks was not evident among whites. Furthermore, change in BP (after--before) was not significantly associated with the genotype. In conclusion, the angiogenin gene AvaII polymorphism is associated with a lower SBP at rest and in response to acute high-intensity exercise in blacks but not in whites.

Familial resemblance for coronary heart disease risk: the HERITAGE Family Study

The objective of this study was to quantify familial resemblance for coronary heart disease risk in 260 Black and 427 White participants in the HERITAGE Family Study. Coronary heart disease risk was estimated using a coronary heart disease risk index (CHDRI) computed from the revised Framingham Heart Study algorithm, based on age, LDL-cholesterol, HDL-cholesterol, blood pressure, diabetes, and smoking status. Using a familial correlation model to test hypotheses regarding familial aggregation, significant familial resemblance was detected in both Blacks and Whites. There were significant sibling correlations in both Blacks and Whites, while spouse correlations were significant only in the White sample. The maximal heritabilities, which have to be interpreted cautiously in light of negligible parent-offspring correlations, were 34% and 53% in Whites and Blacks, respectively. Thus, the maximal heritability, which includes both genetic and non-genetic sources of variation, is higher in Blacks than Whites, and explains a significant proportion of the total phenotypic variance. The results indicate that risk of coronary heart disease runs along family lines, and common environmental effects are important in explaining the observed familial resemblance.

Comparison of the PR mutant with the wild-type strain of proteus mirabilis brings insight into peroxide resistance factors and regulation of catalase expression

The peroxide resistant mutant (PR) of Proteus mirabilis was characterized by an increased constitutive catalase activity concomitant with a large production of specific mRNA. Survival toward hydrogen peroxide during exponential phase was increased by H2O2 pretreatment in the wild type but not in the mutant, although the catalase of both strains was not inducible under these conditions. In the mutant, besides catalase, over-produced proteins comprised two different alkyl hydroperoxide reductase subunit C (AhpC) proteins and a protein homologous to the stationary phase transcription factor SspA of Escherichia coli. Conversely, the flagellin A (FlaA) of P. mirabilis was repressed in the PR mutant. Genomic DNA fragments of 2.9 kb carrying the catalase gene (katA) together with the 5' and 3' flanking regions were isolated from both strains and found to be identical. Upstream of katA, a Fur box-like sequence was found, but surprisingly, restricting iron in the culture medium caused a decrease in catalase production. The PR mutant presents similarities with other peroxide resistant mutants, but the regulation of catalase biosynthesis in P. mirabilis seems somewhat different from other close species such as E. coli.

Heart rate and blood pressure changes with endurance training: the HERITAGE Family Study

PURPOSE

The purpose of this study was to determine the magnitude of change in resting and exercise heart rate (HR) and blood pressure (BP), by race, sex, and age, after a 20-wk endurance training program in 507 healthy and previously sedentary subjects from the HERITAGE Family Study.

METHODS

After baseline measurements, subjects exercised on cycle ergometers 3 d x wk(-1) for a total of 60 exercise sessions starting at 55% of VO2max for 30 min x session(-1) and building to 75% of VO2max for 50 min x session(-1) for the last 6 wk. HR and BP at rest and during exercise (50 W, 60% of VO2max maximal exercise) were each determined in duplicate on two different days both before and after training (resting values at 24-h and 72-h posttraining).

RESULTS

After the period of training, there was a small decrease in resting HR (-2.7 to -4.6 beats x min(-1) across groups at 72-h posttraining), and small changes (i.e., < 3 mm Hg) in resting systolic (SBP), diastolic (DBP), and calculated mean BP (MBP), which varied by race, sex, and age. During exercise at the same absolute work rate (50 W), HR, SBP, DBP, and MBP were all significantly reduced, with greater reductions in HR in women compared with men, and greater reductions in BP in blacks and older subjects compared with whites and younger subjects, respectively. At the same relative work rate (60% VO2max), HR, DBP, and MBP were reduced, but SBP remained unchanged. Blacks had a greater reduction in DBP, but whites had a greater reduction in HR. Finally, at maximal exercise, there was a small decrease in HR, with men and whites decreasing more than women and blacks; an 8 mm Hg increase in SBP, with men increasing more than women; a 4 mm Hg decrease in DBP, with blacks decreasing more than whites; and no change in MBP.

CONCLUSION

In conclusion, the reductions in resting HR and BP with training were generally small, but the reductions during exercise were substantial and clinically important, with the older and the black populations experiencing greater reductions.

Cardiac output and stroke volume changes with endurance training: the HERITAGE Family Study

PURPOSE

The purpose of this study was to determine the magnitude of changes in cardiac output (Qc), stroke volume (SV), and arterial-mixed venous oxygen difference (a-vO2 diff) during submaximal exercise following a 20-wk endurance training program, with the primary focus on identifying differences in response by race, sex, and age.

METHODS

The participants in this study (N = 631) were healthy and previously sedentary men (N = 277) and women (N = 354) of varying age (17-65 yr) and race (blacks, N = 217; whites, N = 414) who had completed the HERITAGE Family Study protocol. After baseline measurements, participants trained on cycle ergometers 3 d x wk(-1) for a total of 60 exercise sessions starting at the HR associated with 55% of maximal oxygen uptake (VO2max) for 30 min/session and building to the HR associated with 75% of VO2max for 50 min/session, which was maintained during the last 6 wk. HR, Qc (CO2 rebreathing), and SV (Qc/HR) were determined in duplicate at 50 W and at 60% of VO2max on two different days both before and after training.

RESULTS

After training, there were significant decreases in HR and Qc, and significant increases in SV and a-vO2 diff at 50 W (except for no change in a-vO2 diff in black men). The changes in HR differed by sex and age, and the changes in SV, Qc, and a-vO2 diff differed by race. Qc decreased by 0.6 L x min(-1) at 50 W for the total sample, consistent with the decrease in VO2 at this power output. At 60% of VO2max HR decreased, and SV, Q, and a-VO2 diff increased. There were small differences in response by sex (HR and SV), race (HR), and age (HR and Qc).

CONCLUSION

It is concluded that the cardiovascular systems of men and women, blacks and whites, and younger and older subjects are not limited in their ability to adapt to endurance training.

NOS3 Glu298Asp genotype and blood pressure response to endurance training: the HERITAGE family study

Endothelium-dependent vasodilation is a mechanism that may affect blood pressure response to endurance training. Because NO plays a central role in this process, the endothelial NO synthase gene is a good candidate for the regulation of exercise blood pressure. We investigated the associations between an endothelial NO synthase gene polymorphism (Glu298Asp) and endurance training-induced changes in resting and submaximal exercise blood pressure in 471 white subjects of the HERITAGE Family Study. Two submaximal exercise tests at 50 W were conducted both before and after a 20-week endurance training program. Steady-state exercise blood pressure was measured twice in each test with an automated unit. The Glu298Asp polymorphism was typed with a PCR-based method and digestion with BAN:II. Both systolic and diastolic blood pressure at 50 W decreased in response to the training program, whereas resting blood pressure remained unchanged. The decrease in diastolic blood pressure at 50 W was greater (P=0.0005, adjusted for age, gender, baseline body mass index, and baseline diastolic blood pressure at 50 W) in the Glu/Glu homozygotes (4.4 [SEM 0.4] mm Hg, n=187) than in the heterozygotes (3.1 [0.4] mm Hg, n=213) and the Asp/Asp homozygotes (1.3 [0.7] mm Hg, n=71). The genotype accounted for 2.3% of the variance in diastolic blood pressure at 50 W training response. Both the Glu298 homozygotes and the heterozygotes had a greater (P=0.013) training-induced reduction in rate-pressure product at 50 W than the Asp298 homozygotes. These data suggest that DNA sequence variation in the endothelial NO synthase gene locus is associated with the endurance training-induced decreases in submaximal exercise diastolic blood pressure and rate-pressure product in sedentary normotensive white subjects.

[External contour acquisition system for radiotherapy: an original solution]

A contour acquisition system has been designed in radiotherapy at the Sagamie Hospital complex (Chicoutimi, Québec) to measure the external contours of the patients who do not need a CT exam. This measuring system can produce transversal, sagittal or coronal patient contours in the treatment position. The absolute accuracy of the system is +/- 1 mm. The contours produced by this equipment can be transferred electronically or on paper to the planning system.

Familial aggregation of stroke volume and cardiac output during submaximal exercise: the HERITAGE Family Study

Familial aggregation of stroke volume (SV) and cardiac output (Qc by CO2 rebreathing) at 50 Watts (W) and 60 % of maximal oxygen uptake (VO2max) as well as their changes in response to a 20-week endurance exercise training program was assessed in 99 Caucasian families who participated in the HERITAGE Family Study. In order to interpret familial influences independent of effects of age, sex, and body size (indexed by body surface area here), SV and Qc levels were adjusted for these primary parameters prior to genetic analysis within four sex-by-generation groups (the responses to training were additionally adjusted for their baseline values). Maximal heritabilities for baseline SV, Qc, and their changes in response to training during the two stages of submaximal exercise were estimated using a familial correlation model. At 50W, maximal heritabilities reached 41% and 42% for baseline SV and Qc, respectively, and were 29% and 38% for the respective responses to training. At 60% of VO2max, maximal heritabilities reached 46 % for baseline SV and Qc, and were 24% and 30% for the respective responses to training. Generally there were no meaningful differences between the maximal heritabilities at 50 W and 60% of VO2max. However, the maximal heritabilities for the baseline were slightly higher than the estimates for the changes in response to training. Based upon results arising from these non-obese, non-hypertensive, and sedentary families, we found that SV and Qc at 50 W and 60% of VO2max as well as their changes in response to the 20-week endurance exercise training were moderately heritable. Not only genetic determinants but also familial non-genetic factors might attribute to the observed patterns of familial aggregation of SV and Qc during submaximal exercise in the present study.

The SepOvotropin: a new ovarian peptide regulating oocyte transport in Sepia officinalis

In the cuttlefish Sepia officinalis, the successive steps of egg laying are controlled by multiple neuropeptides. Recent experiments led us to suppose that there was possible involvement of a second regulation pathway by the release of ovarian regulatory peptides in the genital tract. Using HPLC fractionation and an in vitro biological test, a C-terminal amidated peptide modulating the motility of the Sepia officinalis oviduct was isolated from an extract of vitellogenic ovarian follicles. The mass of this peptide as determined by MALDI-TOF (1501.8 Da) and analysis by Edman degradation led to the following sequence: Pro-Lys-Asp-Ser-Met-Leu-Leu-Leu-Gln-Val-Pro-Val-Tyr-amide. The peptide mapping performed by LC/MS revealed a distribution restricted to the follicles, the full grown oocytes and the eggs. This new peptide, called SepOvotropin, modulated contractions of the whole genital tract in physiological conditions from a threshold concentration between 10(-20) and 10(-19) M, demonstrating for the first time the occurrence of a specific peptidergic control of egg-laying in cephalopods.

A polymorphism in the alpha2a-adrenoceptor gene and endurance athlete status

PURPOSE

In a case control study, we examined the allelic frequencies and genotype distributions of two restricted fragment length polymorphisms (RFLP) in the alpha-2A-adrenoceptor gene (ADRA2A) and beta-2-adrenoceptor gene (ADRB2) among elite endurance athletes (EEA) and sedentary controls (SC).

METHODS

The EEA group included 148 Caucasian male subjects recruited on the basis that they had a VO2max > 74 mL O2 x kg(-1) x min(-1). The SC group comprised 149 unrelated sedentary male subjects, all Caucasians, from the Quebec Family Study. After digestion with the restriction enzymes Dra I (ADRA2A) and Ban I (ADRB2), Southern blotting and hybridization techniques were used to detect the mutations in the two ADR genes, which are encoded on chromosomes 10 (q24-26) and 5 (q31-32), respectively.

RESULTS

For the Dra I ADRA2A RFLP, we observed a significant difference in genotype distributions between the two groups (P = 0.037). A higher frequency of the 6.7-kb allele was observed in the EEA group compared with the SC group (P = 0.013). No statistically significant difference was found between groups for the Ban I ADRB2 polymorphic site. Genotype frequencies for both genes in both groups were in Hardy-Weinberg equilibrium.

CONCLUSIONS

In summary, we found evidence that ADRA2A gene variability detected with Dra I is weakly associated with elite endurance athlete status, and we conclude that genetic variation in the ADRA2A gene or a locus in close proximity may play a role in being able to sustain the endurance training regimen necessary to attain a high level of maximal aerobic power.

ILME: a waterborne pheromonal peptide released by the eggs of Sepia officinalis

A novel tetrapeptide modulating the oviduct contractions was characterized from egg mass of Sepia officinalis. After two purification steps by rpHPLC, an apparent pure fraction containing the biological activity was submitted to MALDI-TOF analysis. The mass spectrum revealed 6 peaks of m/z 293, 505, 596, 613, 728, and 745. The tissue peptide mapping performed in LC-MS demonstrated the occurrence of the m/z 505 peptide in the follicles, the full-grown oocytes, and in the eggs. This peptide was also recovered in the seawater after the incubation of full grown oocytes or eggs, demonstrating a release in the genital tract and in the environment. Edman degradation gave the following sequence: Ileu-Leu-Met-Glu. The synthetic peptide applied to the whole genital tract triggered a cyclisation of the contractions at 10(-14) M. ILME appeared to be a chemical messenger released by the oocytes and the eggs, and was able to exert both paracrine and pheromonal activity.

A genetic study of sex hormone--binding globulin measured before and after a 20-week endurance exercise training program: the HERITAGE Family Study

Familial aggregation and a major gene effect were assessed for baseline serum sex hormone-binding globulin (SHBG) levels and the response (post-training minus baseline) to a 20-week endurance training program in a selected sample of 428 non-obese nonhypertensive individuals from 99 white families who were sedentary at baseline in the HERITAGE Family Study. Baseline SHBG levels were not normally distributed, and were therefore logarithmically transformed prior to genetic analyses. In a sample without postmenopausal mothers, maximal (genetic and familial environmental) heritabilities were 50% averaged across sexes, 73% in men, 50% in women, and 31% in men versus women for the age-body mass index (BMI)-adjusted baseline. The estimate reached 64% when the baseline was further adjusted for the effects of estradiol, fasting insulin, and testosterone levels. For the response to training, no sex difference was found and the heritability reached about 25% to 32%. Segregation analysis was separately performed in the whole sample and in the sample without postmenopausal mothers. In addition to a multifactorial effect for both the baseline and the response to training, a major effect for the baseline appeared to be familial environmental in origin, whereas a major effect for the response to training was Mendelian in nature. The major gene effect for the response to training in the whole sample was undetectable in the sample without postmenopausal mothers, and it is therefore possible that the postmenopausal mothers, characterized by decreased sex hormones with or without estrogen replacement therapy for menopause, produced some confounding effects. In addition, the reduced sample size might also be a plausible candidate explanation. The novel finding in this study is that baseline SHBG levels and the response to training were influenced by a multifactorial effect with sex difference for the baseline. The response to training appeared to be additionally influenced by a single recessive locus that is independent of baseline SHBG levels.

Race, visceral adipose tissue, plasma lipids, and lipoprotein lipase activity in men and women: the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) family study

Abdominal obesity is associated with numerous metabolic alterations, such as hypertriglyceridemia and low levels of high density lipoprotein (HDL) cholesterol. However, compared with abdominally obese white individuals, abdominally obese black individuals have been characterized by higher plasma HDL cholesterol levels, suggesting that the impact of abdominal fat accumulation on the lipoprotein-lipid profile may differ among ethnic groups. Therefore, we have compared the associations between body fatness, visceral adipose tissue (AT) accumulation, and metabolic risk variables in a sample of 247 white men and 240 white women versus a sample of 93 black men and 143 black women. Although no difference in mean total body fatness was found between the 2 race groups, white men had higher levels of visceral AT than did black men (P<0.001). Despite the fact that black women had a greater body fat content than did white women, black women had levels of visceral AT that were similar to those of white women, suggesting a lower susceptibility to visceral obesity in black women. This lower accumulation of visceral AT in blacks was accompanied by significantly reduced apolipoprotein B concentrations and ratios of total cholesterol to HDL cholesterol as well as higher plasma HDL cholesterol levels (P<0.05) compared with those values in whites. Irrespective of sex, higher postheparin plasma hepatic lipase (HL) and lower lipoprotein lipase (LPL) activities were found in whites, resulting in an HL/LPL ratio that was twice as high in whites as in blacks (P<0.005). Although differences in lipoprotein-lipid levels were noted between whites and blacks, results from multiple regression analyses revealed that after control for morphometric and metabolic variables of the study (body fat mass, visceral AT, LPL, HL, and age), ethnicity had, per se, only a minor contribution to the variance in plasma lipoprotein levels. Thus, our results suggest that the higher plasma HDL cholesterol levels and the generally more cardioprotective plasma lipoprotein profile found in abdominally obese black versus white individuals are explained, at least to a certain extent, by a lower visceral AT deposition and a higher plasma LPL activity in black individuals.

Familiality of triglyceride and LPL response to exercise training: the HERITAGE study

PURPOSE

The main purpose of the present investigation was to test whether and to what extent familial/genetic factors are involved in the changes of postheparin lipoprotein lipase (deltaPH-LPL) activity and triglyceride (deltaTG) levels in response to exercise training. Additional hypotheses were also tested as to whether there were familial/genetic factors shared by baseline and the corresponding response to exercise training (i.e., by baseline triglyceride (TG(B)) and deltaTG and by baseline postheparin lipoprotein lipase (PH-LPL(B)) and deltaPH-LPL activity).

METHODS

Serum TG and PH-LPL were measured in 459 subjects from 99 sedentary Caucasian families of the HERITAGE Family study before (baseline) and after completing a 20 wk (3 times per week) exercise training protocol. The training protocol had a target intensity of 75% of the heart rate associated with baseline VO2max during the last 6 wk. PH-LPL activity was measured in the study subjects. Both univariate and bivariate familial correlation analyses were applied to the baseline and response data.

RESULTS

The maximal heritabilities for deltaTG and deltaPH-LPL activity were 22% and 15%, respectively. There were no common familial factors for TG(B) and deltaTG, nor were there any for PH-LPL(B) and deltaPH-LPL. However, we found that there were common familial factors underlying deltaTG and deltaPH-LPL; these familial factors seemed to differ across sex and generation groups.

CONCLUSION

Although there were no common familial factors underlying the covariation between the baseline triglyceride and PH-LPL activity and the corresponding responses to exercise training (i.e., TG(B) with deltaTG or PH-LPL(B) with deltaPH-LPL), the deltaTG and deltaPH-LPL covariation apparently share some common familial determinants.

AGT M235T and ACE ID polymorphisms and exercise blood pressure in the HERITAGE Family Study

We investigated the association between angiotensinogen (AGT) and angiotensin-converting enzyme (ACE) gene polymorphisms and exercise training responses of resting and exercise blood pressure (BP). BP at rest and during submaximal (50 watts) and maximal exercise tests was measured before and after 20 wk of endurance training in 476 sedentary normotensive Caucasian subjects from 99 families. AGT M235T and ACE insertion/deletion polymorphisms were typed with PCR-based methods. Men carrying the AGT MM and MT genotypes showed 3. 7 +/- 0.6 and 3.2 +/- 0.5 (SE) mmHg reductions, respectively, in diastolic BP at 50 watts (DBP(50)), whereas, in the TT homozygotes, the decrease was 0.4 +/- 1.0 mmHg (P = 0.016 for trend, adjusted for age, body mass index, and baseline DBP(50)). Men with the ACE DD genotype showed a slightly greater decrease in DBP(50) (4.4 +/- 0.6 mmHg) than the II and ID genotypes (2.8 +/- 0.7 and 2.4 +/- 0.5 mmHg, respectively, P = 0.050). Furthermore, a significant (P = 0.022) interaction effect between the AGT and ACE genes was noted for DBP(50); the AGT TT homozygotes carrying the ACE D allele showed no response to training. Men with the AGT TT genotype had greater (P = 0.007) diastolic BP (DBP) response to acute maximal exercise at baseline. However, the difference disappeared after the training period. No associations were found in women. These data suggest that, in men, the genetic variation in the AGT locus modifies the responsiveness of submaximal exercise DBP to endurance training, and interactions between the AGT and ACE loci can alter this response.

Reproducibility of resting blood pressure and heart rate measurements. The HERITAGE Family Study

PURPOSE

This study determined the reproducibility of resting systolic and diastolic blood pressure, mean arterial pressure, and heart rate (the average of three measures/day).

METHODS

The data were obtained on two separate days prior to an exercise training intervention in a sample of 822 subjects participating in the HERITAGE Family Study. The same protocol was conducted across three days in an intracenter quality control substudy, which included an additional 60 subjects.

RESULTS

Reproducibility estimates included technical error, coefficient of variation within subjects, and intraclass correlation with results expressed by sex, race, age, cuff size, BMI, and %fat. Since the data were collected across four Clinical Centers, the reproducibility estimates were also computed separately for each Center. The systolic, diastolic, and mean arterial blood pressures were highly reproducible with technical errors less than 5.1 mmHg, coefficients of variation of less than 7. 0% and intraclass correlations > 0.75. The heart rates were slightly less reproducible. These results were fairly consistent across subject populations and across all four Clinical Centers.

CONCLUSION

It is concluded that within subject day-to-day variations are small compared to between subject variance for resting systolic, diastolic, and mean arterial blood pressure and heart rate at each of the Clinical Centers for all of the HERITAGE Family Study data. This makes it appropriate to pool the data and analyze it for changes subsequent to endurance exercise training and to determine the possible genetic basis for these changes.

Squash trypsin inhibitors from Momordica cochinchinensis exhibit an atypical macrocyclic structure

Three trypsin inhibitors (TIs), from the seeds of the squash Momordica cochinchinensis (MCo), have been isolated and purified using gel filtration, ion exchange chromatography, and reverse-phase HPLC. Their sequences could be determined only after proteolytic cleavages. In the case of MCoTI-I and -II, it was shown that their polypeptide backbones are cyclic, a structure that has never been described in squash TIs. They contain 34 amino acid residues with 3 disulfide bridges and measured molecular masses of 3453.0 and 3480.7, respectively. They are the largest known macrocyclic peptides containing disulfide bridges. Their sequences show strong homology to other squash TIs, suggesting a similar three-dimensional structure and an analogous mechanism of action. A model of MCoTI-II was constructed by analogy to the crystal structure of the complex between bovine trypsin and CMTI-I, indicating that the linker connecting the two termini is flexible and does not impose significant geometrical constraints. This flexibility allows an Asp-Gly peptide bond rearrangement to occur in this region, giving rise to two isoforms of MCoTI-II. Although the importance of cyclization is not clear, it might confer increased stability and resistance to proteolysis. A minor species, MCoTI-III, was also characterized as containing 30 amino acid residues with a molecular mass of 3379.6. This component possesses a linear backbone with a blocked N-terminus. MCoTIs represent interesting candidates for drug design, either by changing their specificity of inhibition or by using their structure as natural scaffolds bearing new binding activities.

Complex segregation analysis of blood pressure and heart rate measured before and after a 20-week endurance exercise training program: the HERITAGE Family Study

Complex segregation analysis of baseline resting blood pressure (BP) and heart rate (HR) and their responses to training (post-training minus baseline) were performed in a sample of 482 individuals from 99 white families who participated in the HERITAGE Family Study. Resting BP and HR were measured at baseline and after a 20-week training program. Baseline resting BP and HR were age-adjusted and age-BMI-adjusted, and the responses to training were age-adjusted and age-baseline-adjusted, within four gender-by-generation groups. This study also analyzed the responses to training in two subsets of families: (1) the so-called "high" subsample, 45 families (216 individuals) with at least one member whose baseline resting BP is in the high end of the normal BP range (the upper 95th percentile: systolic BP [SBP] > or = 135 or diastolic BP [DBP] > or = 80 mm Hg); and (2) the so-called "nonhigh" subsample, the 54 remaining families (266 individuals). Baseline resting SBP was influenced by a multifactorial component (23%), which was independent of body mass index (BMI). Baseline resting DBP was influenced by a putative recessive locus, which accounted for 31% of the variance. In addition to the major gene effect, which may impact BMI as well, baseline resting DBP was also influenced by a multifactorial component (29%). Baseline resting HR was influenced by a putative dominant locus independent of BMI, which accounted for 31% of the variance. For the responses to training, no familiality was found in the whole sample or in the nonhigh subsample. However, in the high subsample, resting SBP response to training was influenced by a putative recessive locus, which accounted for 44% of the variance. No familiality was found for resting DBP response to training. Resting HR response to training was influenced by a major effect (accounting for 35% of the variance), with an ambiguous transmission from parents to offspring.

Linkage and association studies of the lipoprotein lipase gene with postheparin plasma lipase activities, body fat, and plasma lipid and lipoprotein concentrations: the HERITAGE Family Study

Lipoprotein lipase (LPL) is responsible for the hydrolysis of triglyceride (TG)-rich lipoproteins. The aims of the present study were (1) to test for potential linkages (sib-pair method) between postheparin plasma lipase (lipoprotein and hepatic lipase) activities, body fatness, plasma lipid concentrations, and LPL polymorphisms (Ser447Ter and a tetranucleotide repeat) and microsatellite markers flanking the LPL locus (D8S261 and D8S258); and (2) to investigate associations between the LPL Ser447Ter (S447X) polymorphism and these phenotypes. Data on 190 parents and 312 adult offspring from 99 Caucasian families participating in the HERITAGE Family Study were available for this study. Data were adjusted for the effects of age within sex, and lipases, lipid variables, and abdominal visceral fat were further adjusted for fat mass. A suggestive linkage was observed only between the S447X polymorphism and very-low-density (VLDL)-apolipoprotein B (apo B) (332 sib-pairs, P = .013). The S447X polymorphism was not associated with body fat phenotypes or postheparin plasma LPL (PH-LPL) activity (men, P = .19; women, P = .47). In contrast, the X447 allele carriers had lower plasma TG (men and women, P = .01), VLDL-TG (men and women, P = .01), and VLDL-apo B (men and women, P = .009). The relationships between the X447 allele and plasma TG, VLDL-TG, and VLDL-apo B in both genders were observed in obese (body mass index [BMI] > or = 30 kg/m2) but not in normal-weight (BMI < 25 kg/m2) subjects. Thus, the S447X polymorphism of the LPL gene is not associated with body fatness and postheparin plasma lipase activities. However, the obese carriers of the X447 allele have plasma TG, VLDL-TG, and plasma cholesterol/high-density lipoprotein cholesterol (HDL-C) levels equivalent to those of normal-weight sedentary adults.

Blood lipid response to 20 weeks of supervised exercise in a large biracial population: the HERITAGE Family Study

We studied the effects of 20 weeks of supervised cycle-ergometer exercise on plasma lipids in 675 healthy, sedentary, normolipidemic white and black men and women aged 17 to 65 years, participating in the HERITAGE Family Study. Fasting plasma lipids were assessed twice at baseline and 24 and 72 hours after the last exercise session and adjusted for plasma volume changes. No significant differences from the mean baseline levels were observed for total, low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) cholesterol and apolipoprotein B (Apo B). A significant reduction (P < .01) from baseline levels in plasma total and VLDL triglycerides was observed only in the 24-hour posttraining specimens, reflecting a response to the last bout of exercise. High-density lipoprotein (HDL) cholesterol increased 3.6% for the combined group, primarily due to an increase in HDL2, with an associated increase in Apo A-1 (P < .001). No significant differences were noted in the HDL response by sex, race, or age. An inverse correlation (r = -.241) was observed between the increase in HDL cholesterol and change in body fat only in men, and the increase in HDL cholesterol was unrelated to the change in maximal oxygen uptake (VO2max).

Segregation analysis of apolipoproteins A-1 and B-100 measured before and after an exercise training program: the HERITAGE Family Study

Complex segregation analyses of apolipoproteins (apo) A-1 and B-100 were performed in a sample of 520 individuals from 99 white families who participated in the HERITAGE Family Study. In these sedentary families, plasma apo A-1 and B-100 concentrations were measured before and after a 20-week endurance exercise training program. Baseline apo A-1 and B-100 were adjusted for the effects of age (age-adjusted baseline apo A-1 and B-100) and for the effects of age and BMI (age-BMI-adjusted baseline apo A-1 and B-100). The change in response to training was computed as a simple Delta (posttraining minus baseline) and was adjusted for age and the baseline (age-baseline-adjusted apo A-1 and B-100 responses to training). In the present study, a major gene could not be inferred for baseline apo A-1. Rather, we found a major effect along with a multifactorial effect accounting for 8% to 9% and 51% to 56% of the variance, respectively. In addition, no clear evidence supported a major-gene effect for its response to training, whereas the transmission of a major effect from parents to offspring was ambiguous, ie, genetic in nature or familial environmental in origin. The major effect accounted for 15% of the variance, with an additional 21% and 58% of the variance being accounted for by a multifactorial effect in parents and offspring, respectively. It is interesting to have obtained evidence of a putative recessive major locus for baseline apo B-100, which accounted for 50% to 56% of the variance, with an additional 25% to 29% of the variance due to a multifactorial effect. In contrast, no major effect for its response to training was identified, although a multifactorial effect was found that accounted for 27% of the variance. The novel findings arising from the present study are summarized as follows. Baseline apo A-1 and its response to training were influenced by a major effect and a multifactorial effect. Baseline apo B-100 was influenced by a putative major recessive gene with a multifactorial component, but its response to training was influenced solely by a multifactorial component in these sedentary families.

Evidence of pleiotropic loci for fasting insulin, total fat mass, and abdominal visceral fat in a sedentary population: the HERITAGE family study

OBJECTIVE

To examine whether there is a major gene effect on fasting insulin and pleiotropic loci for fasting insulin, total fat mass (FM), and abdominal visceral fat (AVF).

RESEARCH METHODS AND PROCEDURES

A major gene hypothesis for fasting plasma insulin levels was assessed using segregation analyses of data on 495 members in 98 normolipidemic sedentary families of white descent who participated in the HERITAGE Family Study.

RESULTS

Segregation analyses were performed on insulin adjusted for age, on insulin adjusted for age and FM, and on insulin adjusted for age and AVF. Before adjustment for AVF and FM, a major gene effect on fasting insulin levels was indicated. The putative locus accounted for 54% of the variance under a recessive inheritance pattern, affecting 11% of the sample (i.e., allele frequency = 0.33). However, after adjusting for the effects of AVF or FM, neither a major effect alone nor a multifactorial component alone could be rejected, and support for a major gene was equivocal, i.e., neither the hypothesis of Mendelian tau values or that of the equal tau(s) were rejected and the equal tau model fit the data better than the Mendelian tau model. This pattern (i.e., major gene evidence for insulin before but not after adjustment for AVF or FM) suggests that there is a putative locus with pleiotropic effects on both insulin and FM and another pleiotropic locus for both insulin and AVF.

DISCUSSION

Although these data do not directly support an additional major gene for insulin independent of AVF and FM, such support cannot be ruled out because there is still a significant major effect on FM- or AVF-adjusted insulin (albeit the Mendelian nature of this effect is ambiguous).

A genetic study of dehydroepiandrosterone sulfate measured before and after a 20-week endurance exercise training program: the HERITAGE Family Study

Familial aggregation and possible major gene effects were evaluated for the baseline serum dehydroepiandrosterone sulfate (DHEAS) level and the change in DHEAS in response to a 20-week exercise training program in a sample of 481 individuals from 99 Caucasian families who were sedentary at baseline and who participated in the HERITAGE Family Study. Baseline DHEAS levels were not normally distributed, and were therefore logarithmically transformed and adjusted for the effects of age and sex prior to genetic analysis. The DHEAS response to training was computed as the simple difference, post-training minus baseline, and was adjusted for the baseline DHEAS level, age, and sex. Maximal (genetic and familial environmental) heritabilities (using a familial correlation model) reached 58% and 30% for the baseline and the response to training, respectively. Our estimate for the baseline is generally in agreement with previous reports, suggesting that the magnitude of the familial effect underlying this phenotype in these sedentary families is similar to that in the general population. However, segregation analysis showed no evidence for a multifactorial familial component in data for either the baseline or the response to training. Rather, a major additive gene controlling the baseline was found. For the response to training in the complete sample, transmission of the major effect from parents to offspring was ambiguous, but in a subset of 56 "responsive" families (with at least 1 family member whose response to training was greater than 1 standard deviation) this major effect was Mendelian in nature. The putative major genes accounted for 50% and 33% of the variance for the baseline and the response to training, respectively. The novel finding in this study is that the baseline DHEAS level and the change in DHEAS in response to training may be influenced by major gene effects.

Angiotensin-converting enzyme ID polymorphism and fitness phenotype in the HERITAGE Family Study

It has been suggested that genetic variation in the angiotensin-converting enzyme (ACE) gene is associated with physical performance. We studied the association between the ACE insertion (I)/deletion (D) polymorphism and several fitness phenotypes measured before and after 20 wk of a standardized endurance training program in sedentary Caucasian (n = 476) and black (n = 248) subjects. Phenotypes measured were oxygen uptake (VO(2)), work rate, heart rate, minute ventilation, tidal volume, and blood lactate levels during maximal and submaximal [50 W and at 60 and 80% of maximal VO(2) (VO(2 max))] exercise and stroke volume and cardiac output during submaximal exercise (50 W and at 60% VO(2 max)). The ACE ID polymorphism was typed with the three-primer PCR method. Out of 216 association tests performed on 54 phenotypes in 4 groups of participants, only 11 showed significant (P values from 0.042 to 0. 0001) associations with the ACE ID polymorphism. In contrast to previous claims, in Caucasian offspring, the DD homozygotes showed a 14-38% greater increase with training in VO(2 max), VO(2) at 80% of VO(2 max), and all work rate phenotypes and a 36% greater decrease in heart rate at 50 W than did the II homozygotes. No associations were evident in Caucasian parents or black parents or offspring. Thus these data do not support the hypothesis that the ACE ID polymorphism plays a major role in cardiorespiratory endurance.

Familial aggregation of amount and distribution of subcutaneous fat and their responses to exercise training in the HERITAGE family study

OBJECTIVE

Investigate the familial aggregation of amount and distribution of subcutaneous fat and their changes in response to endurance training.

RESEARCH METHODS AND PROCEDURES

A total of 483 sedentary subjects from 99 nuclear families were recruited, trained for 20 weeks of exercising on cycle ergometers, and measured before and after training for the following indicators of subcutaneous fat and fat distribution: trunk fat (TRUNK = sum of abdominal, subscapular, suprailiac, and midaxillary skinfolds), extremity fat (EXTREM = sum of biceps, triceps, thigh, and calf skinfolds), subcutaneous fat (SF8 = sum of the eight skinfolds), the trunk to extremity skinfolds ratio adjusted for SF8 (TER) and waist girth adjusted for body mass index (WAIST). The familial aggregation of the age- and sex-adjusted baseline phenotypes and their responses to training (delta) after adjustment for the baseline values was investigated using a familial correlation model.

RESULTS

Significant familial aggregation was observed for all the phenotypes measured at baseline and for deltaTRUNK and deltaWAIST. Transmissibility estimates reached about 30% to 35% for TRUNK, EXTREM, and SF8 and 50% for TER and WAIST. The transmissibilities of the response phenotypes were lower, ranging from 0% for deltaWAIST to 21% for deltaTRUNK and the pattern of familial correlations suggested a greater within- than between-generation resemblance in the response.

DISCUSSION

This study suggests that the amount and distribution of subcutaneous fat strongly aggregates in families, whereas the response to exercise training is characterized by a moderate and more complex pattern of familial resemblance. We conclude that familial/genetic factors are more important in determining the amount and distribution of subcutaneous fat than their responses to exercise training.