Single nucleotide polymorphisms of thrifty genes for energy metabolism: evolutionary origins and prospects for intervention to prevent obesity-related diseases

Serotonin Transporter Gene Polymorphisms Predict Adherence to Weight Loss Programs Independently of Obesity-Related Genes

BACKGROUND/OBJECTIVES

Adherence to treatment instructions is essential in managing chronic diseases related to obesity. One gene associated with adherence is the serotonin transporter (5-HTTLPR) gene, which has long (L) and short (S) alleles, resulting in LL, SL, and SS genotypes. Risk alleles for obesity include the R variant of the β3-adrenergic receptor (β3AR) and the G variant of uncoupling protein 1 (UCP1). This study aimed to evaluate whether the S/L variant of 5-HTTLPR, the R variant of β3AR, and the G variant of UCP1 are associated with adherence to a weight loss program. To assess the factors influencing adherence, eating behavior was evaluated using the Eating Behavior Questionnaire (EBQ).

METHODS

This study included 56 well-educated and middle-class women with a mean age of 57.3 ± 10 years and a mean BMI of 27.2 ± 5.6 kg/m2. Long-read sequencing was used to analyze S/L mutations. Participants followed a six-month diet and exercise regimen for obesity management. Outcomes were assessed using clinical data and EBQ scores. Adherence was objectively measured by the reduction in body fat percentage.

RESULTS

Participants were classified as SS (69.6%), SL (17.9%), or LL (12.5%). The R variant of β3AR was present in 34% of participants, with the G variant of UCP1 in 75%. After the intervention, SS participants showed significantly greater reductions in weight and body fat percentage than LL participants (p < 0.05). Among EBQ items, significant improvements (p < 0.05) were observed in SS participants for eating as a diversion, feeling of fullness, bad eating habits, unsteady eating patterns, and total EBQ score. In SL participants, only bad eating habits improved, whereas no significant changes were observed in LL participants. Obesity risk alleles did not significantly affect clinical outcomes, though there may be small number bias.

CONCLUSIONS

SS genotype participants demonstrated higher adherence to the weight loss program, leading to improved clinical outcomes and EBQ scores, independent of obesity risk genes.

Relation Between Obesity and Type 2 Diabetes: Evolutionary Insights, Perspectives and Controversies

PURPOSE OF REVIEW

Since the mid-twentieth century, obesity and its related comorbidities, notably insulin resistance (IR) and type 2 diabetes (T2D), have surged. Nevertheless, their underlying mechanisms remain elusive. Evolutionary medicine (EM) sheds light on these issues by examining how evolutionary processes shape traits and diseases, offering insights for medical practice. This review summarizes the pathogenesis and genetics of obesity-related IR and T2D. Subsequently, delving into their evolutionary connections. Addressing limitations and proposing future research directions aims to enhance our understanding of these conditions, paving the way for improved treatments and prevention strategies.

RECENT FINDINGS

Several evolutionary hypotheses have been proposed to unmask the origin of obesity-related IR and T2D, e.g., the "thrifty genotype" hypothesis suggests that certain "thrifty genes" that helped hunter-gatherer populations efficiently store energy as fat during feast-famine cycles are now maladaptive in our modern obesogenic environment. The "drifty genotype" theory suggests that if thrifty genes were advantageous, they would have spread widely, but proposes genetic drift instead. The "behavioral switch" and "carnivore connection" hypotheses propose insulin resistance as an adaptation for a brain-dependent, low-carbohydrate lifestyle. The thrifty phenotype theory suggests various metabolic outcomes shaped by genes and environment during development. However, the majority of these hypotheses lack experimental validation. Understanding why ancestral advantages now predispose us to diseases may aid in drug development and prevention of disease. EM helps us to understand the evolutionary relation between obesity-related IR and T2D. But still gaps and contradictions persist. Further interdisciplinary research is required to elucidate complete mechanisms.

Influence of Nutritional Intakes in Japan and the United States on COVID-19 Infection

The U.S. and Japan are both democratic industrialized societies, but the numbers of COVID-19 cases and deaths per million people in the U.S. (including Japanese Americans) are 12.1-times and 17.4-times higher, respectively, than those in Japan. The aim of this study was to investigate the effects of diet on preventing COVID-19 infection. An analysis of dietary intake and the prevalence of obesity in the populations of both countries was performed, and their effects on COVID-19 infection were examined. Approximately 1.5-times more saturated fat and less eicosapentaenoic acid/docosahexaenoic acid are consumed in the U.S. than in Japan. Compared with food intakes in Japan (100%), those in the U.S. were as follows: beef 396%, sugar and sweeteners 235%, fish 44.3%, rice 11.5%, soybeans 0.5%, and tea 54.7%. The last four of these foods contain functional substances that prevent COVID-19. The prevalence of obesity is 7.4- and 10-times greater in the U.S. than in Japan for males and females, respectively. Mendelian randomization established a causal relationship between obesity and COVID-19 infection. Large differences in nutrient intakes and the prevalence of obesity, but not racial differences, may be partly responsible for differences in the incidence and mortality of COVID-19 between the U.S. and Japan.

PPARγ gene Pro12Ala variants reduce the risk of obese individuals to non-alcoholic fatty liver: A study in Uygur Chinese population residing in Northwestern China

OBJECTIVE

To investigate the association of polymorphisms of Pro12Ala of peroxisome proliferator-activated receptor gamma (PPARγ) gene with clinical and biochemical parameters in Uygur Chinese population with non-alcoholic fatty liver (NAFLD) METHODS: In this case-control study, we recruited 467 NAFLD cases and 524 controls. Examination of abdominal ultrasound, clinical and biochemical profiles, as well as polymerase chain reaction-restriction fragment length polymorphisms of Pro12Ala of PPARγ gene were performed. The association of PPARγ gene Pro12Ala variants with clinical and biochemical parameters was analyzed.

RESULTS

There was no statistically significant difference between NAFLD and control groups in the frequencies of genotypic and allele distribution (P>0.05), while significantly difference of genotypic (P=0.032) and allele (P=0.015) distribution was found between NAFLD and control groups in the obese. Using logistics multivariate regression analysis by adjusting age, sex, body mass index, diabetes, hyperuricemia and dyslipidemia, both Pro12Ala and Ala12Ala polymorphisms were not associated with the presence of NAFLD. However, above two polymorphisms were found to be related to NAFLD in obesity group (odds ratio=0.442, P=0.031 and odds ratio=0.039, P=0.010, respectively) CONCLUSION: In Uygur Chinese population, PPARr gene Ala variants reduce the risk of NAFLD in obese individuals.

Influence of K656N Polymorphism of the Leptin Receptor Gene on Obesity-Related Traits in Nondiabetic Afro-Caribbean Individuals

Background: Ethnic variations have been reported in allelic frequencies of the leptin receptor gene (LEPR) with population-specific effects. We aimed to explore the association of LEPR polymorphisms with obesity, metabolic syndrome (MetS), and leptin levels in Afro-Caribbean nondiabetic subjects. Methods: Genotypic analysis of three LEPR polymorphisms (K109R, Q223R, and K656N) was performed using TaqMan allelic discrimination assays. Associations were measured with phenotypic variables, including body mass index (BMI), waist circumference (WC), and leptin levels. Linear and logistic regressions were performed to evaluate the effects of single-nucleotide polymorphisms (SNPs). Results: Mean age was 46 ± 12 years. Among the 375 participants, 29.3% were obese, 36.3% had abdominal obesity, and 18.1% had MetS. Significant association between BMI (P < 0.002) and WC (P < 0.005) was observed for K656N, whereas the associations were not statistically significant for the other two SNPs. No association was found with leptin levels for the three SNPs. The variant allele frequencies for LEPR 109R, 223R, and 656N were 0.16, 0.46, and 0.20, respectively. In dominant models, the variant allele 656N (GC/CC vs. GG) was associated with prevalence of obesity [odds ratio (OR) 1.82; P = 0.012] and abdominal obesity (OR 2.00; P = 0.007), but not significantly with prevalence of MetS (OR 1.72; P = 0.029). Individuals carrying four variant alleles of the three SNPs had a significantly higher risk of obesity (OR 2.86; P = 0.032) than those carrying none variant allele. Conclusion: Our results suggest an influence of K656N polymorphism in the LEPR gene on obesity and abdominal obesity in this Afro-Caribbean population.

Medical cost savings in Sakado City and worldwide achieved by preventing disease by folic acid fortification

The introduction of mandatory fortification of grains with folate in 1998 in the United States resulted in 767 fewer spina bifida cases annually and a cost saving of $603 million per year. However, far more significant medical cost savings result from preventing common diseases, including myocardial infarction, stroke, dementia and osteoporosis. A cost-effectiveness analysis showed a gain of 266 649 quality-adjusted life-years and $3.6 billion saved annually, mainly due to the reduction of cardiac infarction. The recommended folate intake in Japan is 240 μg/day whereas it is 400 μg/day internationally. Our Sakado Folate Project targeted individuals with genetic polymorphism of methylenetetrahydrofolate reductase or with hyperhomocysteinemia. Using, for example, folate-fortified rice, resulted in an increase in serum folate and a decrease in serum homocysteine in the participants, and reduced medical costs were achieved by decreasing myocardial infarction, stroke, dementia and fracture. Due to the small population of Sakado City (approximately 101 000) and small number of births (693) in 2015, a decrease in spina bifida could not be confirmed but there was a significant decrease in the number of very low birthweight infants. The genome notification of subjects was effective in motivating intake of folate, but the increase in serum folate (from 17.4 to 22.5 nmol/L, 129%) was less than that observed following compulsory folic acid fortification of cereals in the USA (from 12.1 to 30.2 nmol/L, 149.6%). Mandatory folic acid fortification is cheap in decreasing medical costs and is thus recommended in Japan.

The genetic association study between polymorphisms in uncoupling protein 2 and uncoupling protein 3 and metabolic data in dogs

Background

The uncoupling proteins (UCPs) in the mitochondrial inner membrane are members of the mitochondrial anion carrier protein family that play an important role in energy homeostasis. Genetic association studies have shown that human UCP2 and UCP3 variants (SNPs and indels) are associated with obesity, insulin resistance, type 2 diabetes mellitus, and metabolic syndrome. The aim of this study was to examine the genetic association between polymorphisms in UCP2 and UCP3 and metabolic data in dogs.

Results

We identified 10 SNPs (9 intronic and 1 exonic) and 4 indels (intronic) in UCP2, and 13 SNPs (11 intronic and 2 exonic) and one indel (exonic) in UCP3, by DNA sequence analysis of 11 different dog breeds (n = 119). An association study between these UCP2 and UCP3 variants and the biochemical parameters of glucose, total cholesterol, lactate dehydrogenase and triglyceride in Labrador Retrievers (n = 50) showed that none of the UCP2 polymorphisms were significantly associated with the levels of these parameters. However, four UCP3 SNPs (intron 1) were significantly associated with total cholesterol levels. In addition, the allele frequencies of two of the four SNPs associated with higher total cholesterol levels in a breed that is susceptible to hypercholesterolemia (Shetland Sheepdogs, n = 30), compared with the control breed (Shiba, n = 30).

Conclusion

The results obtained from a limited number of individuals suggest that the UCP3 gene in dogs may be associated with total cholesterol levels. The examination of larger sample sizes and further analysis will lead to increased precision of these results.

Electronic supplementary material

The online version of this article (doi:10.1186/1756-0500-7-904) contains supplementary material, which is available to authorized users.

Leptin and leptin receptor gene polymorphisms and their association with plasma leptin levels and obesity in a multi-ethnic Malaysian suburban population

Background

This study was to investigate the prevalence of single nucleotide polymorphisms (SNPs) in leptin gene LEP (A19G and G2548A) and leptin receptor gene LEPR (K109R and Q223R) and their association with fasting plasma leptin level (PLL) and obesity in a Malaysian suburban population in Kampar, Perak.

Methods

Convenience sampling was performed with informed consents, and the study sample was drawn from patients who were patrons of the Kampar Health Clinic. A total of 408 subjects (mean age, 52.4 ± 13.7 years; 169 men, 239 women; 190 obese, 218 non-obese; 148 Malays, 177 ethnic Chinese, 83 ethnic Indians) participated. Socio-demographic data and anthropometric measurements were taken, and genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results

The LEP A19G, G2548A and LEPR K109R, Q223R variant allele frequencies were 0.74, 0.67 and 0.61, 0.79, respectively. The genotype and allele distributions of these gene variants were significantly different among ethnic groups, but not among body mass index (BMI) classes. Subjects with LEPR K109 and Q223 allele had significantly higher systolic blood pressure and adiposity indices after adjustment for ethnicity (higher BMI, total body and subcutaneous fat; lower skeletal muscle percentage). Subjects with LEPR 109R allele had lower PLL than their wild-type allele counterparts. The influence of LEP A19G and G2548A SNPs on blood pressures, anthropometrics, and PLL was not evident. Interestingly, synergistic effect of the LEP and LEPR SNPs was observed as subjects homozygous for all four SNPs studied exhibited significantly higher subcutaneous fat and PLL than those with other genotype combinations.

Conclusions

The LEP and LEPR SNPs in this study may not be an obesity marker among Malaysians in this population, but were associated with ethnicity. Our findings suggest that each of these SNPs contributes to minor but significant variation in obesity-related traits and in combination they display synergistic effects on subcutaneous fat and PLL.

CoQ10 and endothelial function in Asians from Korea compared to Asians born in the United States and US born Caucasians

Background

The vascular endothelium is the interface between the blood and vascular smooth muscle in arteries. It is easily damaged by oxidative stress. Recent studies show that Asians are more susceptible than Caucasians to impairment of endothelial function. This study examined endothelial function in US-born Caucasians, Asians from Korea, and US-born Asians (almost all Korean decent) and examined the effect of coenzyme Q10 (CoQ10) on endothelial function.

Material/Methods

Twenty Caucasians and 30 Asians participated (<35 years old, males and females). Endothelial function was assessed by the skin blood flow response to local heat using a thermode for 6 minutes at 44°C and by vascular occlusion for 4 minutes followed by release and measurement of skin blood flow for 2 minutes. In the US-born subjects, the experiments were repeated after 2-week administration of CoQ10 or a placebo.

Results

When applying 6 minutes of local heat at 44°C, the skin blood flows were significantly higher in Caucasians than both Asian groups Asians. Likewise after vascular occlusion, the blood flow response was greater in Caucasians compared to Asians. Asians born in Asia had the lowest response of the 3 groups of subjects. Administering CoQ10 for 2 weeks eliminated much of the difference between the groups, whereas there was no difference with a placebo.

Conclusions

These findings suggest that Asians either born in Asia or the US may have lower endothelial function than Caucasians. This may be explained, in part, by genetic variations causing increased oxidative stress from westernized diets in Asians. Co enzyme Q10 administration narrows the difference between the groups.

The genetics of childhood obesity and interaction with dietary macronutrients

The genes contributing to childhood obesity are categorized into three different types based on distinct genetic and phenotypic characteristics. These types of childhood obesity are represented by rare monogenic forms of syndromic or non-syndromic childhood obesity, and common polygenic childhood obesity. In some cases, genetic susceptibility to these forms of childhood obesity may result from different variations of the same gene. Although the prevalence for rare monogenic forms of childhood obesity has not increased in recent times, the prevalence of common childhood obesity has increased in the United States and developing countries throughout the world during the past few decades. A number of recent genome-wide association studies and mouse model studies have established the identification of susceptibility genes contributing to common childhood obesity. Accumulating evidence suggests that this type of childhood obesity represents a complex metabolic disease resulting from an interaction with environmental factors, including dietary macronutrients. The objective of this article is to provide a review on the origins, mechanisms, and health consequences of obesity susceptibility genes and interaction with dietary macronutrients that predispose to childhood obesity. It is proposed that increased knowledge of these obesity susceptibility genes and interaction with dietary macronutrients will provide valuable insight for individual, family, and community preventative lifestyle intervention, and eventually targeted nutritional and medicinal therapies.

Differences in endothelial function between Korean-Asians and Caucasians

Background

The vascular endothelium plays an integral role in maintaining vascular homeostasis, including the regulation of blood flow, vascular tone, and platelet aggregation. The aim of this study was to see if there were any differences in endothelial function between Koreans and Caucasians.

Material/Methods

This was accomplished by 2 measures of endothelial function – the response to local heat and the response to vascular occlusion. Ten Caucasian and 10 Korean male and female subjects participated (<35 years old). Endothelial function was assessed by the skin blood flow response to local heat using a thermode for 6 minutes at 3 temperatures (38°C, 40°C and 42°C) and by vascular occlusion for 4 minutes followed by release and measurement of skin blood flow for 2 minutes.

Results

When applying 6 minutes of local heat at 3 different temperatures (38°C, 40°C, and 42°C), the skin blood flows were significantly higher for all temperatures in Caucasians as compared with Koreans, with peak blood flow of 223±48.1, 413.7±132.1, and 517.4±135.8 flux in Caucasians and 126.4±41.3, 251±77.9, and 398±97.2 flux in Koreans, respectively (p=0.001). Results of this study support the idea that the skin blood flow response to occlusion was significantly higher in Caucasians (peak 411.9±88.9 flux) than Koreans (peak 332.4±75.8 flux) (p=0.016).

Conclusions

These findings suggest that Koreans may have lower endothelial function than Caucasians, which may be explained, in part, by genetic variations between the 2 ethnic groups.

The evolution of human adiposity and obesity: where did it all go wrong?

Because obesity is associated with diverse chronic diseases, little attention has been directed to the multiple beneficial functions of adipose tissue. Adipose tissue not only provides energy for growth, reproduction and immune function, but also secretes and receives diverse signaling molecules that coordinate energy allocation between these functions in response to ecological conditions. Importantly, many relevant ecological cues act on growth and physique, with adiposity responding as a counterbalancing risk management strategy. The large number of individual alleles associated with adipose tissue illustrates its integration with diverse metabolic pathways. However, phenotypic variation in age, sex, ethnicity and social status is further associated with different strategies for storing and using energy. Adiposity therefore represents a key means of phenotypic flexibility within and across generations, enabling a coherent life-history strategy in the face of ecological stochasticity. The sensitivity of numerous metabolic pathways to ecological cues makes our species vulnerable to manipulative globalized economic forces. The aim of this article is to understand how human adipose tissue biology interacts with modern environmental pressures to generate excess weight gain and obesity. The disease component of obesity might lie not in adipose tissue itself, but in its perturbation by our modern industrialized niche. Efforts to combat obesity could be more effective if they prioritized 'external' environmental change rather than attempting to manipulate 'internal' biology through pharmaceutical or behavioral means.

Association between PPARγ2 Pro12Ala polymorphism and myocardial infarction and obesity in Han Chinese in Hohhot, China

Activation of the peroxisome proliferator-activated receptor g (PPARg) improves insulin sensitivity and inhibits atherosclerosis. Whether PPARg2 Pro12Ala polymorphism affects myocardial infarction is not clearly understood. We investigated a possible association of PPARg2 Pro12Ala polymorphism with obesity and myocardial infarction in Han Chinese in Hohhot, Inner Mongolia, China. We included 121 subjects with myocardial infarction and 137 healthy controls in our study. Triglycerides, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were measured. The following information was recorded for each subject: age, gender, body height, body weight, systolic blood pressure, and diastolic blood pressure; the body mass index was calculated. PCR-RFLP was used to examine Pro12Ala polymorphism. There were significant differences in clinical characteristics between myocardial infarction patients and healthy controls, except for diastolic blood pressure and triglycerides. The PP, PA/AA genotype frequencies were 88.4 and 11.6% in myocardial infarction patients and 95.6 and 4.4% in controls, respectively (P = 0.031). Individuals with the A allele had a significantly higher risk of myocardial infarction. The A allele was not an independent risk factor for obesity. We conclude that PPARg2 Pro12Ala polymorphisms are associated with increased risk for myocardial infarction in Han Chinese in Hohhot.

[Evolutionary endocrinology: a pending matter]

Twenty years have passed since the foundational article of what is now known as evolutionary medicine (EM) was published. This young medical discipline examines, following Darwinian principles, susceptibility to certain diseases and how we react to them. In short, EM analyzes the final cause of the disease from a historical perspective. Over the years, EM has been introduced in various medical areas in very different ways. While it has found a role in some fields such as infectious diseases and oncology, its contribution in other areas has been quite limited. In endocrinology, EM has only gained prominence as a basis for the so-called "diseases of civilization", including diabetes mellitus and obesity. However, many experts suggest that it may have a much higher potential. The aim of this paper is to provide a view about what evolutionary medicine is. Some examples of how EM may contribute to progress of our specialty are also given. There is no doubt that evolution enriches medicine, but medicine also offers knowledge to evolution.

Association between variants of the leptin receptor gene (LEPR) and overweight: a systematic review and an analysis of the CoLaus study

BACKGROUND

Three non-synonymous single nucleotide polymorphisms (Q223R, K109R and K656N) of the leptin receptor gene (LEPR) have been tested for association with obesity-related outcomes in multiple studies, showing inconclusive results. We performed a systematic review and meta-analysis on the association of the three LEPR variants with BMI. In addition, we analysed 15 SNPs within the LEPR gene in the CoLaus study, assessing the interaction of the variants with sex.

METHODOLOGY/PRINCIPAL FINDINGS

We searched electronic databases, including population-based studies that investigated the association between LEPR variants Q223R, K109R and K656N and obesity- related phenotypes in healthy, unrelated subjects. We furthermore performed meta-analyses of the genotype and allele frequencies in case-control studies. Results were stratified by SNP and by potential effect modifiers. CoLaus data were analysed by logistic and linear regressions and tested for interaction with sex. The meta-analysis of published data did not show an overall association between any of the tested LEPR variants and overweight. However, the choice of a BMI cut-off value to distinguish cases from controls was crucial to explain heterogeneity in Q223R. Differences in allele frequencies across ethnic groups are compatible with natural selection of derived alleles in Q223R and K109R and of the ancient allele in K656N in Asians. In CoLaus, the rs10128072, rs3790438 and rs3790437 variants showed interaction with sex for their association with overweight, waist circumference and fat mass in linear regressions.

CONCLUSIONS

Our systematic review and analysis of primary data from the CoLaus study did not show an overall association between LEPR SNPs and overweight. Most studies were underpowered to detect small effect sizes. A potential effect modification by sex, population stratification, as well as the role of natural selection should be addressed in future genetic association studies.

Association of beta3-adrenergic receptor (ADRB3) Trp64Arg gene polymorphism with obesity and metabolic syndrome in the Balinese: a pilot study

BACKGROUND

Prevalence of obesity is increasing all over the world. ADRB3 Trp64Arg gene polymorphism was proposed to be associated with obesity, although inconsistent findings and differences of the Arg64 allele frequency among various ethnics were reported. Westernization was reported to increase the prevalence of obesity in developing world. In this study we determined the prevalence of obesity and metabolic syndrome among urban and rural Balinese, and studied the association of ADRB3 Trp64Arg polymorphism with obesity and MetS.

FINDINGS

A total of 528 Balinese (urban 282, rural 246) were recruited. Body mass index (BMI) and waist circumference (WC) were determined; high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), systolic and diastolic blood pressure (SBP and DBP), and fasting plasma glucose (FPG) were measured using standard procedures. BMI and WC classifications were based on WHO classifications for Asian. Metabolic syndrome (MetS) was defined as described in the Joint Interim Statement. Chi-square test was employed to test the association between the ADRB3 Trp64Arg genotype and disease traits.Urban have higher BMI (p = 2.8 × 10-13), WC ( p < 2.2 × 10-16), TG (p = 0.0028), DBP (p = 1.8 × 10-5), and lower HDL-C (p = 0.0376) when compared to rural. Abdominal obesity and MetS prevalence were significantly higher in urban as compared to rural (both p < 0.001). The Arg64 allele frequency was similar between urban (0.06) and rural (0.05). The Arg64 rural female carriers have higher BMI and WC as compared to their Trp64 counterparts (p = 0.041 for BMI and p = 0.012 for WC), and consequently higher abdominal obesity prevalence (p = 0.007). Comparison between male and female, as well as urban and rural, showed different prevalence of MetS co-morbidities. Abdominal obesity and hypertriglyceridaemia were consistently appeared in all groups, suggesting to play a role as determinant of MetS in both urban and rural.

CONCLUSIONS

Prevalence of obesity and MetS in urban were two times higher when compared to rural. Abdominal obesity and hypertriglyceridaemia appears to be the key determinant of MetS in both urban and rural Balinese. Our results indicated an association of the ADRB3 Trp64Arg gene polymorphism with obesity in the rural female.

Worldwide spatial genetic structure of angiotensin-converting enzyme gene: a new evolutionary ecological evidence for the thrifty genotype hypothesis

As JV Neel put forward the 'thrifty genotype' hypothesis, many researches tend to support this hypothesis involved in the regulation of energy balance. However, the phrase could equally well encapsulate broader traits and the forms of thrift should be multiple. In particular, genes involved in the regulation of water and sodium balance may also be excellent candidates as thrifty genes. In the present study, we selected the ancestral D allele of angiotensin-converting enzyme (ACE) gene, a key gene involved in water and sodium balance regulation, as a candidate to confirm the 'thrifty genotype' hypothesis in the framework of evolutionary ecology. On the basis of our compiled worldwide spatial genetics database of I/D frequency of ACE gene and spatial climate database, using techniques of spatial statistics, we found (1) an obvious decreasing geographic genetic cline following the route of out-of-Africa expansion from East Africa, (2) a positive association between D allele and synthetic temperature factor, (3) and a negative relationship between D allele and synthetic humidity factor that covered most regions of the world, and obvious spatial dependence between D allele and these two climate factors followed the route of out-of-Africa expansion from Africa. This suggested that D allele of ACE gene is not only plastic in response to its environmental circumstance but also presents a striking geographic distribution showing the evidence of 'signatures of selection' by climate factors. Thus, it can be identified as a thrifty allele and could provide a new evolutionary ecological evidence for the 'thrifty genotype' hypothesis.

Socioeconomic disparities in self-reported cardiovascular disease for Indigenous and non-Indigenous Australian adults: analysis of national survey data

Background

Little is known about the relationship between socioeconomic status (SES) and cardiovascular disease (CVD) among Indigenous Australians, or whether any such relationship is similar to that in non-Indigenous Australians.

Methods

Weighted data on self-reported CVD and several SES measures were analyzed for 5,417 Indigenous and 15,432 non-Indigenous adults aged 18-64 years from two nationally representative surveys conducted in parallel by the Australian Bureau of Statistics in 2004-05.

Results

After adjusting for age and sex, self-reported CVD prevalence was generally higher among those of lower SES in both the Indigenous and non-Indigenous populations. The relative odds of self-reported CVD were generally similar in the two populations. For example, the relative odds of self-reported CVD for those who did not complete Year 10 (versus those who did) was 1.4 (95% confidence interval [CI]: 1.1-1.8) among Indigenous people and 1.3 (95% CI: 1.2-1.5) among non-Indigenous people. However, Indigenous people generally had higher self-reported CVD levels than non-Indigenous people of the same age and SES group. Although smoking history varied by SES, smoking did not explain the observed relationships between SES and self-reported CVD.

Conclusions

Socioeconomic disparities in self-reported CVD among Indigenous Australians appear similar in relative terms to those seen in non-Indigenous Australians, but absolute differences remain. As with other population groups, the socioeconomic heterogeneity of the Indigenous population must be considered in developing and implementing programs to promote health and prevent illness. In addition, factors that operate across the SES spectrum, such as racism, stress, dispossession, and grief, must also be addressed to reduce the burden of CVD.

Thrift: a guide to thrifty genes, thrifty phenotypes and thrifty norms

There is a growing interest in evolutionary models of human adiposity. Frequent reference has been made to 'thrifty genes' or 'thrifty phenotypes', referring to a variety of metabolic or behavioural traits that in one or the other way imply frugality in the expenditure or storage of energy. However, there is confusion over how the strategy of thrift has been incorporated into human biology. At the broadest level, humans represent a thrifty species relative to other mammals, indicating that metabolic adaptations had a crucial role in the emergence of the Homo lineage, in particular in buffering reproduction from ecological stochasticity. In contemporary humans, some variability in adiposity may be attributable to genotypes systematically favoured in certain ecological settings. Genetic variability is also present within populations, and may be considered bet hedging (distributing risk across offspring to increase parental fitness). Bet hedging is an alternative to genetic drift for accounting for genetic variability in the absence of strong selective pressures. Contrasting with genetic variability emerging over the long-term, thrifty phenotypes represent a response to short-term ecological variability. Physiological plasticity allows the emergence of variability across the life course in response to ecological cues experienced directly or by very recent ancestors. Finally, cultural norms or individual preferences allow voluntary behavioural manipulation of thrift in individuals. Overall, there is a range of factors and processes both favouring and opposing thrifty genes, which may reflect moderate bet hedging rather than systematic adaptation. Plasticity protects the genome from selective pressures by tailoring the organism to ongoing ecological conditions. The fact that obesity can occur in different individuals through different genotypes, life histories and behaviours indicates that different treatments are also likely to be required.

Socio-economic gradients in self-reported diabetes for Indigenous and non-Indigenous Australians aged 18-64

OBJECTIVE

To examine and compare socio-economic gradients in diabetes among Indigenous and non-Indigenous Australians.

METHODS

I analysed weighted data on self-reported diabetes and a range of socio-economic status (SES) measures for 5,417 Indigenous and 15,432 non-Indigenous adults aged 18-64 years from two nationally representative surveys conducted in parallel by the Australian Bureau of Statistics in 2004-05.

RESULTS

After adjusting for age, diabetes prevalence was significantly higher among those of lower SES in both Indigenous and non-Indigenous populations. The age- and sex-adjusted odds ratios (OR) for diabetes for the lowest versus the highest SES group were similar for the two populations on many variables. For example, the OR for the lowest quintile of equivalised household income (compared with quintiles 3-5 combined) was 2.3 (95% CI 1.6-3.4) for the Indigenous population and 2.0 (95% CI 1.5-2.8) for the non-Indigenous population. However, Indigenous people of high SES had greater diabetes prevalence than low SES non-Indigenous people on every SES measure examined.

CONCLUSION

Socio-economic status explains some but not all of the difference in diabetes prevalence between Indigenous and non-Indigenous Australians. Other factors that may operate across the socio-economic spectrum, such as racism, stress, loss and grief, may also be relevant and warrant further examination.

IMPLICATIONS

Indigenous Australians do not constitute a homogeneous group with respect to socio-economic status or diabetes prevalence, and this diversity must be recognised in developing measures to redress Indigenous health disadvantage.

Automated single nucleotide polymorphism typing using bead array in capillary tube

A low-cost and simple on-site technique for genotyping single nucleotide polymorphisms (SNPs) was developed. The technique is based on allele-specific primer PCR and the recently developed bead arrays in a single tip technique. The performance of the method was verified by genotyping four SNPs that correlate with cardiovascular diseases.

ATP synthase: from single molecule to human bioenergetics

ATP synthase (F(o)F(1)) consists of an ATP-driven motor (F(1)) and a H(+)-driven motor (F(o)), which rotate in opposite directions. F(o)F(1) reconstituted into a lipid membrane is capable of ATP synthesis driven by H(+) flux. As the basic structures of F(1) (alpha(3)beta(3)gammadeltaepsilon) and F(o) (ab(2)c(10)) are ubiquitous, stable thermophilic F(o)F(1) (TF(o)F(1)) has been used to elucidate molecular mechanisms, while human F(1)F(o) (HF(1)F(o)) has been used to study biomedical significance. Among F(1)s, only thermophilic F(1) (TF(1)) can be analyzed simultaneously by reconstitution, crystallography, mutagenesis and nanotechnology for torque-driven ATP synthesis using elastic coupling mechanisms. In contrast to the single operon of TF(o)F(1), HF(o)F(1) is encoded by both nuclear DNA with introns and mitochondrial DNA. The regulatory mechanism, tissue specificity and physiopathology of HF(o)F(1) were elucidated by proteomics, RNA interference, cytoplasts and transgenic mice. The ATP synthesized daily by HF(o)F(1) is in the order of tens of kilograms, and is primarily controlled by the brain in response to fluctuations in activity.

Variants in neuropeptide Y receptor 1 and 5 are associated with nutrient-specific food intake and are under recent selection in Europeans

There is a large variation in caloric intake and macronutrient preference between individuals and between ethnic groups, and these food intake patterns show a strong heritability. The transition to new food sources during the agriculture revolution around 11,000 years ago probably created selective pressure and shaped the genome of modern humans. One major player in energy homeostasis is the appetite-stimulating hormone neuropeptide Y, in which the stimulatory capacity may be mediated by the neuropeptide Y receptors 1, 2 and 5 (NPY1R, NPY2R and NPY5R). We assess association between variants in the NPY1R, NPY2R and NPY5R genes and nutrient intake in a cross-sectional, single-center study of 400 men aged 40 to 80 years, and we examine whether genomic regions containing these genes show signatures of recent selection in 270 HapMap individuals (90 Africans, 90 Asians, and 90 Caucasians) and in 846 Dutch bloodbank controls. Our results show that derived alleles in NPY1R and NPY5R are associated with lower carbohydrate intake, mainly because of a lower consumption of mono- and disaccharides. We also show that carriers of these derived alleles, on average, consume meals with a lower glycemic index and glycemic load and have higher alcohol consumption. One of these variants shows the hallmark of recent selection in Europe. Our data suggest that lower carbohydrate intake, consuming meals with a low glycemic index and glycemic load, and/or higher alcohol consumption, gave a survival advantage in Europeans since the agricultural revolution. This advantage could lie in overall health benefits, because lower carbohydrate intake, consuming meals with a low GI and GL, and/or higher alcohol consumption, are known to be associated with a lower risk of chronic diseases.

PPARγ2 polymorphism and human health

The nuclear hormone receptor peroxisome proliferator activated receptor gamma (PPARγ) is an important transcription factor regulating adipocyte differentiation, lipid and glucose homeostasis, and insulin sensitivity. Numerous genetic mutations of PPARγ have been identified and these mutations positively or negatively regulate insulin sensitivity. Among these, a relatively common polymorphism of PPARγ, Pro12Ala of PPARγ2, the isoform expressed only in adipose tissue has been shown to be associated with lower body mass index, enhanced insulin sensitivity, and resistance to the risk of type 2 diabetes in human subjects carrying this mutation. Subsequent studies in different ethnic populations, however, have revealed conflicting results, suggesting a complex interaction between the PPARγ2 Pro12Ala polymorphism and environmental factors such as the ratio of dietary unsaturated fatty acids to saturated fatty acids and/or between the PPARγ2 Pro12Ala polymorphism and genetic factors such as polymorphic mutations in other genes. In addition, this polymorphic mutation in PPARγ2 is associated with other aspects of human diseases, including cancers, polycystic ovary syndrome, Alzheimer disease and aging. This review will highlight findings from recent studies.

Single nucleotide polymorphism and lifestyle-related diseases in the Asia-Pacific region: comparative study in Okinawa, Palau and Thailand

Genetic differences between Asians and Caucasians may be involved in the rapid increase in lifestyle-related diseases in the Asia-Pacific region that has coincided with Westernisation of diets in the region. In the present study, we assessed correlation between 10 single nucleotide polymorphisms (SNPs) and chronic disease risk factors in age-matched and population-based groups in four Asian-Pacific locations: Okinawa, Palau and Thailand (two areas). The following allelic SNP profiles significantly differed (p<0.01) among the four populations, in both men and women: uncoupling protein 2 (UCP2), uncoupling protein 3 promoter (UCP3p), leptin receptor (LEPR) exon 6, and angiotensinogen (AGTa-20c). Multiple regression analyses showed significant associations between SNPs and clinical data. For men, these associations were between beta3 adrenergic receptor (beta3AR) and diastolic blood pressure (DBP) (p<0.01), UCP3p and total cholesterol (p<0.01), UCP2 and age (p<0.05), and AGTa-20c and age (p<0.01). For women, these associations were between LEPR exon 14 and body mass index (BMI) (p<0.05), UCP2 and systolic blood pressure (p<0.05), UCP3p and DBP (p<0.05), UCP2 and DBP (p<0.01), apolipoprotein E (ApoE)nd total cholesterol (p<0.01), beta3AR and triglyceride (p<0.05), AGTa-20c and triglyceride (p<0.05), and UCP2 and age (p<0.05). These results illustrate the interrelationships among SNPs and risk factors in the Asia-Pacific including China and Japan.

Gene-environment association of an ITGB2 sequence variant with obesity in ethnic Japanese

Mice lacking the integrin alphaMbeta2 (Mac-1, CD11b/CD18) develop an obese phenotype on western diet rich in fat. However, no association has been found between variations in the human genes encoding the integrin alphaMbeta2 and obesity. This study was aimed to investigate the association between a single-nucleotide polymorphism (SNP) (rs235326) in the gene encoding human integrin beta2 subunit (ITGB2) with obesity. Our subject cohort comprised 651 people of Japanese ethnicity, of which 274 were Japanese Americans living in Hawaii, and the remaining 377 were native Japanese, two populations in the same genetic background with or without westernized life style. We genotyped the rs235326 polymorphism using a TaqMan assay. In the Japanese-American population, the risk of obesity was found to be 3.29-fold higher (a 95% confidence interval of 1.25-8.67, P = 0.02) in TT homozygotes than in C carriers, using a recessive model and logistic regression analysis that had been adjusted for age. This association was not found in native Japanese individuals. These results indicate that the rs235326 polymorphism in the ITGB2 gene is associated with obesity in Japanese living in the United States whose diet has become "westernized."

The biology of the colonizing ape

Hominin evolutionary history is characterized by regular dispersals, cycles of colonization, and entry into novel environments. This article considers the relationship between such colonizing capacity and hominin biology. In general, colonizing strategy favors rapid rates of reproduction and generalized rather than specialized biology. Physiological viability across diverse environments favors a high degree of phenotypic plasticity, which buffers the genome from selective pressures. Colonizing also favors the capacity to access and process information about environmental variability. We propose that early hominin adaptive radiations were based upon the development of such capacities as adaptations to unstable Pliocene environments. These components came together, along with fundamental changes in morphology, behavior, and cognition in the genus Homo, who exploited them in subsequent wider dispersals. Middle Pleistocene hominins and modern humans also show development of further traits, which correspond with successful probing of, and dispersals into, stressful environments. These traits have their precursors in primate or ape biology, but have become more pronounced during hominin evolution. First, short interbirth intervals and slow childhood growth allow human females to provision several offspring simultaneously, increasing the rate of reproduction in favorable conditions. This allows rapid recovery from population crashes, or rapid population growth in new habitats. Second, despite high geographical phenotypic variability, humans have high genetic unity. This is achieved by a variety of levels of plasticity, including physiology, behavior, and technology, which reduce the need to commit to genetic adaptation. Hominin behavior may increasingly have shaped both the ecological niches occupied and the selective pressures acting back on the genome. Such selective pressures may have been exacerbated by population dynamics, predicted to both derive from, and favor, the colonizing strategy. Exposure to ecological variability is likely to have generated particular selective pressures on female biology, favoring increasing steering of offspring ontogeny by maternal phenotype. We propose that the concept of hominins as "colonizing apes" offers a novel unified model for interpreting the suite of traits characteristic of our genus.

Relationship between mitochondrial DNA mutations and clinical characteristics in human lung cancer

Mitochondrial DNA (mtDNA) is known for its high frequencies of polymorphisms and mutations, some of which are related to various diseases, including cancers. However, roles of mutations and polymorphisms in some diseases are among heated debate, especially for cancer. To investigate the possible role of mtDNA mutations in lung cancer, we sequenced complete mtDNA of lung cancer tissues, corresponding normal (i.e., non-cancerous) lung tissues, and peripheral blood samples from 55 lung cancer patients and examined the relationship between mtDNA mutations or polymorphisms and clinical parameters. We identified 56 mutations in 33 (60%) of the 55 patients, including 48 point mutations, four single-nucleotide insertions, and four single-nucleotide deletions. Nineteen of these mutations resulted in amino acid substitution. These missense mtDNA mutations were distributed in 9 of 13 mitochondrial DNA coding genes. Three hundred eighty eight polymorphisms were identified among the 55 patients. Seventy-three polymorphisms resulted in amino acid substitution. There was no association of incidence of specific mtDNA mutation or polymorphism with patients' gender, age at diagnosis, smoking history, tumor type or tumor stage (P>0.05). This study revealed a variety of mtDNA mutations and mtDNA polymorphisms in human lung cancer, some of which might be involved in human lung carcinogenesis.

Methodological aspects of the assessment of gene-nutrient interactions at the population level

Nutritional-related diseases are the result of complex interactions between genes and diet. The understanding of these interactions will provide the rationale for dietary interventions based on the individual's genetic constitution. However, the approach to this kind of study is not easy, the complexity of the interactions increasing exponentially the dimensionality of the problem. The aim of this review is to analyze the major problems that arise in approaching complex interactions at the population level. Furthermore, several statistical tools available for this type of analysis are discussed. In conclusion, although analytic techniques able to reduce the dimensionality of the problem are suggested, sample size requirement seems to remain an inescapable challenge for the researcher. A synergy between traditional and nontraditional statistical approaches could be useful.

The thrifty phenotype as an adaptive maternal effect

Human diseases in adulthood are increasingly associated with growth patterns in early life, implicating early-life nutrition as the underlying mechanism. The thrifty phenotype hypothesis proposed that early-life metabolic adaptations promote survival, with the developing organism responding to cues of environmental quality by selecting an appropriate trajectory of growth. Recently, some authors have proposed that the thrifty phenotype is also adaptive in the longer-term, by preparing the organism for its likely adult environment. However, windows of plasticity close early during human development, and subsequent environmental changes may result in the selected trajectory becoming inappropriate, leading to adverse effects on health. This paradox generates uncertainty as to whether the thrifty phenotype is indeed adaptive for the offspring in humans. The thrifty phenotype should not be considered a dichotomous concept, rather it refers to the capacity of all offspring to respond to environmental information during early ontogenetic development. This article argues that the thrifty phenotype is the consequence of three different adaptive processes - niche construction, maternal effects, and developmental plasticity - all of which in humans are influenced by our large brains. While developmental plasticity represents an adaptation by the offspring, both niche construction and parental effects are subject to selection on parental rather than offspring fitness. The three processes also operate at different paces. Human offspring do not become net calories-producers until around 18 years of age, such that the high energy costs of the human brain are paid primarily by the mother, even after weaning. The evolutionary expansion of human brain volume occurred in environments characterised by high volatility, inducing strong selective pressure on maternal capacity to provision multiple offspring simultaneously. The thrifty phenotype is therefore best considered as a manipulation of offspring phenotype for the benefit of maternal fitness. The information that enters offspring phenotype during early development does not predict the likely future environment of the offspring, but rather reflects the mother's own developmental experience and the quality of the environment during her own maturation. Offspring growth trajectory thus becomes aligned with long-term maternal capacity to provision. In contemporary populations, the sensitivity of offspring development to maternal phenotype exposes the offspring to adverse effects, through four distinct pathways. The offspring may be exposed to (1) poor maternal metabolic control (e.g. gestational diabetes), (2) maternally derived toxins (e.g. maternal smoking), or (3) low maternal social status (e.g. small size). Adverse consequences of these effects may then be exacerbated by (4) exposure either to the "toxic" western environment in postnatal life, in which diet and physical activity levels are mismatched with metabolic experience in utero, or at the other extreme to famine. The rapid emergence of the epidemic of the metabolic syndrome in the 20th Century reflects the rapid acceleration in the pace of niche construction relative to the slower physiological combination of developmental plasticity and parental effects.

A strategy to search for common obesity and type 2 diabetes genes

Worldwide, the incidence of type 2 diabetes is rising rapidly, mainly because of the increase in the incidence of obesity, which is an important risk factor for this condition. Both obesity and type 2 diabetes are complex genetic traits but they also share some nongenetic risk factors. Hence, it is tempting to speculate that the susceptibility to type 2 diabetes and obesity might also partly be due to shared genes. By comparing all of the published genome scans for type 2 diabetes and obesity, five overlapping chromosomal regions for both diseases (encompassing 612 candidate genes) have been identified. By analysing these five susceptibility loci for type 2 diabetes and obesity, using six freely available bioinformatics tools for disease gene identification, 27 functional candidate genes have been pinpointed that are involved in eating behaviour, metabolism and inflammation. These genes might reveal a molecular link between the two disorders.

The evolution of human fatness and susceptibility to obesity: an ethological approach

Human susceptibility to obesity is an unusual phenomenon amongst animals. An evolutionary analysis, identifying factors favouring the capacity for fat deposition, may aid in the development of preventive public health strategies. This article considers the proximate causes, ontogeny, fitness value and evolutionary history of human fat deposition. Proximate causes include diet composition, physical activity level, feeding behaviour, endocrine and genetic factors, psychological traits, and exposure to broader environmental factors. Fat deposition peaks during late gestation and early infancy, and again during adolescence in females. As in other species, human fat stores not only buffer malnutrition, but also regulate reproduction and immune function, and are subject to sexual selection. Nevertheless, our characteristic ontogenetic pattern of fat deposition, along with relatively high fatness in adulthood, contrasts with the phenotype of other mammals occupying the tropical savannah environment in which hominids evolved. The increased value of energy stores in our species can be attributed to factors increasing either uncertainty in energy availability, or vulnerability to that uncertainty. Early hominid evolution was characterised by adaptation to a more seasonal environment, when selection would have favoured general thriftiness. The evolution of the large expensive brain in the genus Homo then favoured increased energy stores in the reproducing female, and in the offspring in early life. More recently, the introduction of agriculture has had three significant effects: exposure to regular famine; adaptation to a variety of local niches favouring population-specific adaptations; and the development of social hierarchies which predispose to differential exposure to environmental pressures. Thus, humans have persistently encountered greater energy stress than that experienced by their closest living relatives during recent evolution. The capacity to accumulate fat has therefore been a major adaptive feature of our species, but is now increasingly maladaptive in the modern environment where fluctuations in energy supply have been minimised, and productivity is dependent on mechanisation rather than physical effort. Alterations to the obesogenic environment are predicted to play a key role in reducing the prevalence of obesity.

A forkhead in the road to longevity: the molecular basis of lifespan becomes clearer

OBJECTIVE

Although the quest for longevity is as old as civilization itself, only recently have technical and conceptual advances in genomics research brought us to the point of understanding the precise molecular events that make us age. This heralds an era when manipulations of these will enable us to live longer, healthier lives. The present review describes how recent experimental strategies have identified key genes and intracellular pathways that are responsible for ageing and longevity.

FINDINGS

In diverse species transcription factors belonging to the forkhead/winged helix box gene, group O (FOXO) subfamily have been found to be crucial in downstream suppression of the life-shortening effects of insulin/insulin-like growth factor-I receptor signalling pathways that, when upregulated, accelerate ageing by suppression of FOXO. The various adverse processes activated upon FOXO suppression include increased generation of reactive oxygen species (ROS). ROS are pivotal for the onset of various common conditions, including hypertension, atherosclerosis, type 2 diabetes, cancer and Alzheimer's disease, each of which shortens lifespan. In humans, FOXO3a, as well as FOXO1 and -4, and their downstream effectors, could hold the key to counteracting ageing and common diseases. An understanding of the processes controlled by these FOXOs should permit development of novel classes of agents that will more directly counteract or prevent the damage associated with diverse life-threatening conditions, and so foster a life of good health to a ripe old age. Just like caloric restriction, lifespan can be increased in various species by plant-derived polyphenols, such as resveratrol, via activation of sirtuins in cells. Sirtuins, such as SIRT1 in mammals, utilize FOXO and other pathways to achieve their beneficial effects on health and lifespan.

CONCLUSION

Lifespan is tractable and basic mechanisms are now known. Longevity research complements and overlaps research in most major medical disciplines. Current progress bodes well for an ever-increasing length of healthy life for those who adapt emerging knowledge personally (so-called 'longevitarians').

Serotonin transporter polymorphisms affect human blood glucose control

We measured the effect of nutritional intervention on clinical data, including fasting blood glucose (FBG), and their association with polymorphisms of the serotonin transporter-linked polymorphic region (5-HTTLPR) which might affect adherence. Enrolled in the intervention program were 264 Japanese women not on medication for diabetes, hypercholesterolemia or hypertension. The 5-HTTLPR allele (S and L) frequencies among the subjects differed markedly from those of Caucasians: SS (n = 183), LS (n = 69), and LL (n = 12). The decrease in FBG (DeltaFBG) from the beginning to the end of the program (11 weeks; short-term study), and DeltaFBG from the beginning to a follow-up check performed between 2002 and 2004 (average of 23 years later; long-term study) was calculated. The SS homozygotes of 5-HTTLPR showed larger DeltaFBG (P = 0.01 and P < 0.0001 in the short- and long-term studies, respectively) than DeltaFBG with other genotypes.

Mitochondrial genome polymorphisms associated with type-2 diabetes or obesity

Although a strong correlation between type-2 diabetes and obesity has been found, no comparative analysis between diabetes and obesity has been performed with respect to mitochondrial DNA (mtDNA) polymorphisms. To test the hypothesis that certain mitochondrial single nucleotide polymorphisms (mtSNPs) might be associated with obesity or type-2 diabetes, we determined the entire sequences of the mitochondrial genomes from 96 patients with type-2 diabetes and those from 96 young obese adults by direct sequencing and compared the frequencies of mtSNPs between these two groups. A mtSNP, 8684C > T (T53I) in the mitochondrial ATP synthase subunit 6 gene (ATP6), was detected in 5 of the 96 patients with type-2 diabetes, whereas this substitution was not detected in any of the 96 young obese adults. Two mtSNPs, 3497C > T (A64V) in NADH dehydrogenase subunit 1 gene (ND1) and 1119T > C (472U > C) in the 12S rRNA gene, were detected in 5 of the 96 young obese adults, whereas these substitutions were not detected in any of the 96 diabetic patients. The 8684C > T transition associated with type-2 diabetes represents haplogroup M8a, and the 3497C > T and 1119T > C transitions predisposing to obesity represent haplogroup B4c. These results suggest that distinct mtSNPs contribute to susceptibility to type-2 diabetes or obesity, pointing out the necessity of large-scale case control studies.

Gene--nutrition interactions in coronary artery disease: correlation between the MTHFR C677T polymorphism and folate and homocysteine status in a Korean population

INTRODUCTION

Elevated plasma total homocysteine is a major risk for coronary artery disease (CAD). Methyltetrahydrofolate reductase (MTHFR) is a main regulatory enzyme in homocysteine metabolism; a common C677T mutation in the MTHFR gene results in decreased enzyme activity, and contributes to increased homocysteine levels and decreased folate levels. We investigated the frequency of MTHFR C677T alleles in a Korean population, determined the genotype-specific threshold levels of folate or vitamin B12, and investigated the relationship between the TT genotype and the risk of CAD.

MATERIALS AND METHODS

We enrolled a study population of 163 CAD patients and 50 control subjects, and screened the MTHFR C677T polymorphism using real-time PCR with melting point analysis. Levels of plasma homocysteine, folate and vitamin B12 were also determined. We then defined the genotype-specific threshold values of folate and vitamin B12 required to keep homocysteine levels in a normal range for individuals of each MTHFR C677T genotype.

RESULTS

The frequency of the TT genotype was 18% in control subjects and 26% in patients group (P>0.05). Individuals homozygous for the TT genotype had significantly elevated homocysteine levels (P<0.05). The genotype-specific folate threshold level was significantly higher in TT individuals than in the CC or CT genotypes. The OR of individuals with low folate status and the TT genotype to estimate the relative risk of CAD was 2.2 and the OR of those with high folate status and the TT genotype was 1.5 (95% CI, 0.5-9.6 and 0.7-3.2, respectively).

CONCLUSION

We were able to define a gene-nutrient interaction that shows a higher risk for CAD based on specific threshold folate levels required by different MTHFR C677T genotypes in a Korean population.

Life-long echoes--a critical analysis of the developmental origins of adult disease model

The hypothesis that there is a developmental component to subsequent adult disease initially arose from epidemiological findings relating birth size to either indices of disease risk or actual disease prevalence in later life. While components of the epidemiological analyses have been challenged, there is strong evidence that developmental factors contribute to the later risk of metabolic disease--including insulin resistance, obesity, and heart disease--as well as have a broader impact on osteoporosis, depression and schizophrenia. We suggest that disease risk is greater when there is a mismatch between the early developmental environment (i.e., the phase of developmental plasticity) versus that experienced in mature life (i.e., adulthood), and that nutritional influences are particularly important. It is also critical to distinguish between those factors acting during the developmental phase that disrupt development from those influences that are less extreme and act through regulated processes of epigenetic change. A model of the relationship between the developmental and mature environment is proposed and suggests interventional strategies that will vary in different population settings.

Genómica de la regulación del peso corporal: mecanismos moleculares que predisponen a la obesidad

Obesity has become a worldwide public health problem which affects millions of people. Substantial progress has been made in elucidating the pathogenesis of energy homeostasis over the past few years. The fact that obesity is under strong genetic control has been well established. Twin, adoption and family studies have shown that genetic factors play a significant role in the pathogenesis of obesity. Human monogenic obesity is rare in large populations. The most common form of obesity is considered to be a polygenic disorder. New treatments are currently required for this common metabolic disease and type 2 diabetes. The identification of physiological and biochemical factors that underlie the metabolic disturbances observed in obesity is a key step in developing better therapeutic outcomes. The discovery of new genes and pathways involved in the pathogenesis of such a disease is critical to this process. However, identification of genes that contribute to the risk of developing the disease represents a significant challenge since obesity is a complex disease with many genetic and environmental causes. A number of diverse approaches have been used to discover and validate potential new genes for obesity. To date, DNA-based approaches using candidate genes and genome-wide linkage analysis have not had a great success in identifying genomic regions or genes involved in the development of these diseases. Recent advances in the ability to evaluate linkage analysis data from large family pedigrees (using variance components-based linkage analysis) show great promise in robustly identifying genomic regions associated with the development of obesity. Studying rare mutations in humans and animal models has provided fundamental insight into a complex physiological process, and has complemented population-based studies that seek to reveal primary causes. Remarkable progress has been made in both fronts and the pace of advance is likely to accelerate as functional genomics and the human genome project expand and mature. Approaches based on Mendelian and quantitative genetics may well converge, and ultimately lead to more rational and selective therapies.

Gene-nutrient and gene-gene interactions of controlled folate intake by Japanese women

Elevated serum total homocysteine (tHcy) levels are associated with increased risk for cardiovascular disease and dementia. The prevalence rates of homozygous mutants among Japanese women (n = 300) were 17.3%, 1.3%, 18.6%, and 5.3% for methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, reduced folate carrier (RFC-1) A80G, and methionine synthase (MS) A2756G, respectively. The tHcy value was significantly lower (p < 0.001) in young women with CC or CT of MTHFR than with TT (10.9+/-4.7 micromol/L) (n =250). Diversities of serum folate and tHcy in women with 23 combinations of different alleles at low folate intake converged to the highest (34.0+/-8.6 nmol/L) and lowest (7.6+/-1.5 micromol/L) levels, respectively, after folic acid (400 microg/day) supplementation. In the regression equation ( y= ax + b) of serum folate ( y nmol/L) plotted against mean folate intake ( x microg/day), the values of "a" were 0.032, 0.037, and 0.045 for individuals with CC, CT, and TT alleles, respectively, of MTHFR.

Phenotypic linkage between single-nucleotide polymorphisms of beta3-adrenergic receptor gene and NADH dehydrogenase subunit-2 gene, with special reference to eating behavior

The beta(3)-adrenergic receptor gene (BAR-3) allelic variant (Trp64Arg and Arg64Arg) is correlated with obesity or non-insulin-dependent diabetes mellitus. The mitochondrial NADH dehydrogenase subunit-2 gene (ND2) variant (Mt5178A) is associated with longevity or less susceptibility to adult-onset diseases. The frequencies of both the variants are high among the Japanese population. Cross-sectional analysis of these variants was conducted to determine if they correlated well with life-style-related phenotypes and nutrient intake. The body fat rate in the BAR-3 variant+ND2 variant group was higher than those rates in the BAR-3 normal+ND2 variant, BAR-3 normal+ND2 normal. The BAR-3 normal+ND2 variant group preferred much carbohydrate and less animal protein compared with other three groups. A combination of SNPs of the nuclear BAR-3 and the mitochondrial ND2 genes may affect eating behavior besides the biochemical and metabolic process of signal transduction and electron transfer system.

Approach to analysis of single nucleotide polymorphisms by automated constant denaturant capillary electrophoresis

Melting gel techniques have proven to be amenable and powerful tools in point mutation and single nucleotide polymorphism (SNP) analysis. With the introduction of commercially available capillary electrophoresis instruments, a partly automated platform for denaturant capillary electrophoresis with potential for routine screening of selected target sequences has been established. The aim of this article is to demonstrate the use of automated constant denaturant capillary electrophoresis (ACDCE) in single nucleotide polymorphism analysis of various target sequences. Optimal analysis conditions for different single nucleotide polymorphisms on ACDCE are evaluated with the Poland algorithm. Laboratory procedures include only PCR and electrophoresis. For direct genotyping of individual SNPs, the samples are analyzed with an internal standard and the alleles are identified by co-migration of sample and standard peaks. In conclusion, SNPs suitable for melting gel analysis based on theoretical thermodynamics were separated by ACDCE under appropriate conditions. With this instrumentation (ABI 310 Genetic Analyzer), 48 samples could be analyzed without any intervention. Several institutions have capillary instrumentation in-house, thus making this SNP analysis method accessible to large groups of researchers without any need for instrument modification.

Improvement in blood lipid levels by dietary sn-1,3-diacylglycerol in young women with variants of lipid transporters 54T-FABP2 and -493g-MTP

In a double-blind parallel-group study, serum lipids and visceral fat/total fat ratio in young women (n=49) with variants of lipid transporters, i.e., fatty acid binding protein 2 (FABP2) and microsomal triglyceride transfer protein (MTP), were analyzed by substituting dietary triacylglycerol (TAG) with sn-1,3-diacylglycerol (DAG). All subjects, including some with the hyperlipidemia-prone genotypes Ala54Thr of FABP2 and c-493g of MTP, received DAG or TAG (20 g/day) for 8 weeks. Reductions of serum lipids from weeks 4 to 8 in FABP2-Ala54Thr heterozygotes and MTP -493g homozygotes were significantly different between the DAG and TAG groups (p<0.05, p<0.01). Visceral fat/total fat (%), as determined by computed tomography (CT), was lower in FABP2-Ala54Thr heterozygotes (p<0.05) of the DAG group. The apoCII/CIII ratio was higher in the DAG group than in the TAG group (p<0.01). Other variants of lipid metabolism, including peroxisome proliferator activated receptors (PPARs) alpha and gamma and SREBP cleavage-activating protein (SCAP), were only slightly affected by dietary DAG.

CONCLUSION

improvement of serum lipid profiles and visceral fat/total fat ratio (CT) was potentiated by DAG intake in subjects with hyperlipidemia-prone genotypes (Ala54Thr heterozygotes of FABP2 and -493g homozygotes of MTP).