Apolipoprotein C3 SstI polymorphism in the risk assessment of CAD.

Various population studies have reported the association of rare S2 allele of apolipoprotein C3 (APOC3) SstI polymorphism with hypertriglyceridemia (HTG) and coronary artery disease (CAD). We were the first to report an association of S2 allele with high triglyceride (TG) levels in healthy volunteers from Northern India. Since HTG is suggested to be a predominant risk factor for CAD among Indians, we have elucidated the relationship of APOC3 SstI polymorphism with the lipid profile and CAD. A total of 158 patients with > or = 70% stenosis in one or more coronary artery (angiographically proven CAD patients), 35 subjects with < 70% stenosis (NCAD) and 151 normal controls (free of heart disease) from Northern plains of India were recruited in the study. DNA samples were analyzed by polymerase chain reaction (PCR) followed by SstI digestion. Lipid profile was estimated by enzymatic kit. We found a strong association of S2 allele with high TG levels, which was more significant in patients. Prevalence of S2 allele in normal controls and CAD patients were comparable, despite the fact that mean TG level was significantly higher in patients. A greater insight into this observation revealed that the prevalence of high TG, if not coupled with other risk factors (like high total cholesterol, low HDL), was comparable in patients and controls. Thus, our study reveals that rare S2 allele may be employed as a susceptibility marker for high TG. However, high TG or S2 allele alone may not contribute to the etiology of CAD.

Lipoprotein(a) as a marker of coronary artery disease and its association with dietary fat.

OBJECTIVE: The main objectives of the study were to evaluate the effect of dietary fat on plasma lipoprotein(a) [Lp(a)] levels and to study the potential of Lp(a) as a more reliable marker for CAD compared to other lipids and lipoproteins. METHODS: Twenty CAD patients and 20 healthy controls were recruited for the study. Their fasting plasma Lp(a) levels and complete lipid profile were assayed. The fat intake was calculated using 24 hours dietary recall method. The patients and controls were each divided into two subgroups: Group A consuming dietary fat > 30% and Group B consuming dietary fat < or = 30% of the total kilo-calories/day. RESULTS: Results indicated that plasma Lp(a), total serum cholesterol (TC), tryglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and LDL-C/HDL-C ratio of CAD patients were significantly higher than the controls. High fat intake was found to be associated with higher plasma Lp(a) levels (p<0.05) in patients only. No significant correlation was found between Lp(a) levels and other conventional lipoproteins. CONCLUSION: The lack of correlation between Lp(a) and other lipoproteins indicates its potential as an independent risk factor for CAD. High fat intake led to higher plasma Lp(a) levels in patients; hence it would be worthwhile to evaluate the effect of quality and quantity of fat intake on plasma Lp(a) levels in a larger sample size.

Study of apolipoproteinc3 Sstl polymorphism in healthy volunteers from Northern India.

Several studies including a small case-control (hypertriglyceridemic/normotriglyceridemic individuals) study by us revealed close association between rare S2 allele ofAPOC3 Sstl polymorphism and hypertriglyceridemia. With the understanding that Asian Indians are highly vulnerable to the adverse effects of hypertriglyceridemia, we extended the investigation and studied the frequency distribution of this polymorphism in 216 healthy volunteers from Northern plains of India. We found that more than 50% of the study population had one or two S2 allele. This may suggest that a larger fraction of this population is genetically predisposed to hypertriglyceridemia.

Apolipoprotein C3 SstI polymorphism and triglyceride levels in Asian Indians.

BACKGROUND: A close association between Sst I polymorphism in the 3' untranslated region of the apolipoproteinC3 (APOC3) gene and levels of plasma triglycerides (TG) had been reported by different investigators. Hypertriglyceridemia(HTG) is a known risk factor for coronary artery disease (CAD) in the context of Asian Indians. We conducted a study on the relationship between APOC3 SstI polymorphism (S1S1, S1S2 and S2S2 genotypes) and plasma TG levels in a group of 139 male healthy volunteers from Northern India. METHODS: DNA samples were analyzed by polymerase chain reaction (PCR) followed by SstI digestion. Digested PCR products were run on 3% agarose gel and visualized by ethidium bromide staining. RESULTS: Rare S2 allele was highly prevalent in our study population (0.313) as compared to the Caucasians (0.00-0.11). The genotypic distribution was in agreement with Hardy-Weinberg equilibrium. S2 allele was almost two times more prevalent in the HTG group (N = 34) as compared to NTG group (N = 105) (p = 0.001). Multiple logistic regression revealed S1S2 individuals had age-adjusted odds ratio of 2.43 (95%CI = 0.99-6.01, p = 0.054) and S2S2 had 9.9 (95%CI = 2.66-37.29, p = 0.0006) for developing HTG in comparison to S1S1 genotype. CONCLUSIONS: Our study shows a significant association between rare S2 allele and HTG in Asian Indians.

Polymorphism (C677T) in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene: A preliminary study on north Indian men.

An elevated level of plasma homocysteine, sulfur containing amino acid generated through demethylation of methionine has been widely accepted as a risk factor for cardiovascular disease (CVD). The increase can result from genetic and/or nutrient related disturbances in the remethylation or transsulfuration pathways for homocysteine metabolism. A common mutation (C677T) in the gene encoding for the enzyme 5, 10-methylenetetrahydrofolate reductase (MTHFR) or deficiency of the B vitamins namely folic acid, B(12), B(6) can lead to hyperhomocysteinemia.In the present study, we have investigated the incidence of the (C677T) MTHFR polymorphism in the North Indian males. 141 angiographically proven coronary artery disease (CAD) patients and 55 age and sex matched healthy volunteers were examined for the association between MTHFR gene polymorphism and CAD. The MTHFR genotyping was performed using polymerase chain reaction (PCR) followed by restriction-isotyping with Hinf 1 endonuclease. A trend for higher 'T' allele frequency (0.19) was observed in patients than in controls (0.16). However no significant association was found between C677T mutation and CAD severity. The lack of statistical significance could be due to the small sample size studied. Hence a larger study including various ethnic groups is warranted.

Does moderate alcohol intake protect against coronary heart disease?

There is abundant epidemiological and clinical evidence to show that light-to-moderate drinking is associated with a reduced risk of coronary heart disease (CHD), total and ischemic stroke, and total mortality in middle-aged and elderly men and women. The evidence suggests a J- or U-shaped relationship between alcohol and CHD. Alcohol reduces the risk of coronary heart disease both by inhibiting the formation of atheroma and by decreasing the rate of blood coagulation. It appears that for most conditions, other than cardiovascular diseases and cholelithiasis, moderate alcohol consumption has either none or only an intermediate type of risk as compared with the risk of either abstinence or excessive drinking. It is now fully recognized and accepted that drinking alcohol regularly for years is toxic to almost every tissue of the body. However, most people who choose to drink alcohol have little or no problem limiting their consumption to amounts that do not generally cause serious health or social consequences. Moreover, a given dose of alcohol may affect different people differently. It is, therefore, imperative that a critical evaluation, based on the observations made hitherto, be done of both the harmful and the protective effects of alcohol consumption on various organs/systems of the body. This article reviews epidemiological evidence for the protective effects of alcohol on the cardiovascular system and discusses how alcohol might lower the risk of CHD.

Metabolic and ethnic determinants of alcohol drinking habits and vulnerability to alcohol-related disorder.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Shoji Harada and Dharam P. Agarwal. The presentations were (1) Mutations in the exons, exon-intron junctions, and promoter regions of human CYP2E1 gene and alcoholism, by Fumio Nomura; (2) Genetic variability in alcohol metabolism and drinking habits in Japanese, by Shoji Harada; (3) Genetic studies of alcohol dependence using alcoholics with inactive ALDH2, by Susumu Higuchi; and (4) Alcohol consumption, apolipoprotein polymorphisms, and cardiovascular disorders, by Dharam P. Agarwal.

Methylenetetrahydrofolate reductase (MTHFR). Incidence of the C677T mutation in a Siberian female population.

We have studied the distribution of genotypes of the MTHFR gene among the Siberian female population and compared it with the frequency of this mutation in different populations. The TT genotype and the T allele frequency in 299 women from Novosibirsk (West Siberia) was determined. The presence of the C677T allele was determined by PCR and Hinf I digestion. The homozygous genotype TT was detected in 8.69% of the population sample. The frequency of the C677T mutant allele was found to be 0.290.

Knowledge amongst adult population regarding vectors of malaria in 21 states of India.

Malaria is the world's most important tropical disease which kills more people than any other disease except tuberculosis. It is a public health problem in more than 90 countries, inhabited by a total of some 2400 million people, 40% of the world's population. More than 90% of all malaria cases are in sub Saharan Africa, with two thirds of the remainder concentrated in six countries viz. India, Brazil, Sri Lanka, Afghanistan, Vietnam and Columbia in decreasing order of prevalence. Even now the problem of malaria in India is grossly underestimated. A rough estimate of morbidity due to malaria made on the basis of consumption of antimalarials comes to 35.5 million episodes in addition to malaria cases treated by the National Anti Malaria Programme (NAMP). In addition to large scale morbidity and mortality, it affects agricultural and industrial produce causing great socioeconomic losses.

Genetic polymorphisms of alcohol metabolizing enzymes.

Alcohol metabolism is one of the biological determinants that can significantly influence drinking behavior and the development of alcoholism and alcohol-induced organ damage. Most ethanol elimination occurs by oxidation to acetaldehyde and acetate, catalyzed principally by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). Other ethanol oxidation pathways, including catalase and microsomal ethanol-oxidizing system (MEOS/CYP2E1), as well as the nonoxidative pathway (FAEES), which forms fatty acid ethyl esters, appear to play a minor role. The major alcohol metabolizing enzymes exhibit genetic polymorphism and ethnic variation. In this review recent advances in the understanding of the functional polymorphisms of ADH, ALDH and CYP2E1 and their metabolic, physiologic and clinical correlations are presented.

Apolipoprotein(a) polymorphism and its association with plasma lipoprotein(a) levels: a north Indian study.

Elevated levels of lipoprotein(a) has been regarded as an independent risk factor for coronary, peripheral and cerebral atherosclerosis. The enormous intra-personal variation in the plasma concentration of lipoprotein(a) is almost entirely controlled by the apolipoprotein(a) i.e. gene locus on the chromosome 6q 26-27. The apolipoprotein(a) molecule is highly polymorphic and is known to exist in multiple, genetically determined isoforms. These polymorphisms may be responsible for difference in promoter activity, variable size of apolipoprotein(a) and thereby variation in plasma lipoprotein(a) concentration. We studied the effect of two types of polymorphisms, (i) variation in length of the pentanucleotide repeat in the 5' flanking region starting -1373 bp upstream of AUG codon, and (ii) the Kringle-4 type 2 size polymorphism, on plasma lipoprotein(a) levels in North Indian population. The study group consisted of 88 angiographically assessed male coronary artery disease patients (age range 30-70 years) and 83 age- and sex-matched healthy controls. The pentanucleotide repeat polymorphism was analysed using polymerase chain reaction. In all, 8/11 pentanucleotide repeat isoforms were observed. Using SDS-agarose gel electrophoresis and immunoblotting isoforms having 12-50 Kringle-4 type 2 repeats were detected. Our study indicates a strong association of elevated plasma lipoprotein(a) concentration with coronary artery disease. An inverse correlation was seen between lipoprotein concentration and isoform size for both the pentanucleotide repeat polymorphism and the Kringle-4 type 2 polymorphisms; statistically significant difference (p = 0.001) was, however, observed only for the later.

High salivary acetaldehyde after a moderate dose of alcohol in ALDH2-deficient subjects: strong evidence for the local carcinogenic action of acetaldehyde.

BACKGROUND: Due to a point mutation, aldehyde dehydrogenase-2 (ALDH2) isoenzyme is deficient in 30% to 50% of Asians. Among Asian ALDH2-deficient heavy drinkers, the risk for digestive tract cancers is markedly increased (odds ratio 3.4-54.2). The reason for this is unknown but could be due to the local carcinogenic action of acetaldehyde. METHODS: Salivary and blood acetaldehyde levels were determined in 20 healthy Asians after a moderate dose of alcohol (0.5 g/kg of body weight). Salivary acetaldehyde production capacity from ethanol in vitro was measured also. ALDH2 genotype of the Asians was determined from isolated leukocyte-deoxyribonucleic acid by polymerase chain reaction/restriction fragment length polymorphism method. Acetaldehyde content of parotid gland saliva was measured in three ALDH2-deficient Asians and three White subjects with normal ALDH2 after the same dose of ethanol. RESULTS: Seven of the Asians were heterozygous for the mutant ALDH2*2 allele (flushers). They had two to three times higher salivary acetaldehyde levels than the Asians (n = 13) with normal ALDH2 throughout the follow-up period of 240 min (p < 0.001). Only in the flushers did the parotid gland contribute to salivary acetaldehyde production. The in vitro capacity of saliva to produce acetaldehyde from ethanol was equal in both groups. The flushers' blood acetaldehyde levels were only one ninth of the levels in saliva. CONCLUSIONS: By using this human "knockout model" for deficient acetaldehyde removal, we found that in addition to oral microflora, acetaldehyde in saliva may also originate from the oxidation of ethanol in the parotid gland. When combined with earlier epidemiological data, these results offer a strong evidence for the local carcinogenic action of acetaldehyde in humans.

Ursolic acid isolated from Eucalyptus tereticornis protects against ethanol toxicity in isolated rat hepatocytes.

Ursolic acid is the active material isolated from the leaves of the Eucalyptus hybrid E. tereticornis. In the present study, it has shown a significant preventive effect in vitro against ethanol-induced toxicity in isolated rat hepatocytes. Compared with the incubation of isolated hepatocytes with ethanol only, the simultaneous presence of ursolic acid in the cell suspension preserved the viability of hepatocytes and reversed the ethanol-induced loss in the level of all the marker enzymes (AST, ALT and AP) studied. Ethanol alone resulted in a 48%-54% decrease in the viability and a 42%-54% reduction in the biochemical parameters of the hepatocytes. Ursolic acid showed a concentration dependent (1-100 microg/mL) preventive effect (12%-76%) on alcohol-induced hepatocyte toxicity by restoring the altered parameters. The results thus suggest the effective use of an in vitro test system as an alternative for in vivo assessment of hepatoprotective activity of purified material.

[Genetic predisposition for alcoholism]. / Genetische Prädisposition zur Alkoholkrankheit.

A number of socio-economic, cultural, biobehavioral factors and ethnic/gender differences are among the strongest determinants of drinking patterns in a society. Both epidemiological and clinical studies have implicated the excessive use of alcohol in the risk of developing a variety of organ, neuronal and metabolic disorders. Alcohol abuse related metabolic derangements affect almost all body organs and their functions. Race and gender differences in drinking patterns may play an important role in the development of medical conditions associated with alcohol abuse. The incidence of alcoholism in a community is influenced by per capita alcohol consumption and covariates with the relative price and availability of alcoholic drinks. The majority of the family, twin and adoption studies suggest that alcoholism is familial, a significant proportion of which can be attributed to genetic factors. The question is how much of the variance is explained by genetic factors and to what degree is this genetically mediated disorder moderated by personal characteristics. Among the most salient personal characteristics moderating, the genetic vulnerability may be factors such as age, ethnicity, and presence of psychiatric co morbidity. Cultural factors and familial environmental factors are most likely predictors as well.

LP(a) phenotypes and levels in angiographically proven coronary heart disease patients and controls.

Lipoprotein Lp(a) excess has been identified as a powerful predictor of premature atherosclerotic vascular diseases. To evaluate this in a North-Indian population, 130 CAD patients and 130 controls were analyzed. The size of the apo(a) phenotypic isoforms was inversely proportional to Lp(a) concentrations. The mean concentration of Lp(a) in the CAD patients was 42±34 mg/dl whereas in the normal subjects it was much lower, 27±27 mg/dl. 157 subjects out of the total 260 subjects showed plasma levels of >20mg/dl. The frequency of high Lp(a) levels was much higher in patients(73%) than controls (43%). These data suggest (1) that there is heterogeneity of the Lp(a) polymorphism, (2) Higher Lp(a) levels were found in patients than in the controls, (3) Patients showed 1.5 fold increase in Lp(a) levels as compared to the controls. We conclude that low molecular weight apo(a) isoforms are significantly associated with increased risk of CAD in the North-Indian population.

Molecular genetic aspects of alcohol metabolism and alcoholism.

Recent human genetic studies suggest that a predisposition to alcohol abuse and/or to develop alcoholism may be inherited. Pedigree analysis, linkage, and association studies have helped to detect marker loci and candidate genes that may prove useful in identifying individuals at risk. In particular, molecular genetic research into the causes of alcoholism has drawn attention to the potentially important role of alcohol- and acetaldehyde-metabolizing enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). Functional polymorphisms have been observed at various genes encoding these enzyme proteins, all of which act to alter the rate of synthesis of the toxic metabolite acetaldehyde, or decrease its further oxidation. The occurrence of functional polymorphisms in alcohol-metabolizing enzymes makes them favored candidate genes suitable for further molecular genetic research. A positive selection of such genetic polymorphisms in some populations might act as a protective factor against alcohol abuse and alcohol-related disease outcomes. For example, individuals who show initial sensitivity to alcohol by virtue of their genetically controlled abnormality of ALDH2*2 allele are discouraged from excessive alcohol consumption. On the other hand, persons with the heterozygous ALDH2*2 genotype (ALDH2*1/2*2) are at higher risk for developing alcohol abuse-related end-organ damage than those with a homozygous ALDH2*1/2*1 genotype. Moreover, the frequency of C2 allele of cytochrome P45 02E1 was found to be higher in patients with nonfibrotic alcoholic liver disease than in patients with severe hepatic fibrosis or liver cirrhosis. Identification of putative alcoholism vulnerability genes by direct analysis of candidate genes and genetic linkage may therefore help improve approaches to prevention and treatment.

Picroliv protects against alcohol-induced chronic hepatotoxicity in rats.

Daily administration of ethyl alcohol (3.76 g/kg, p.o.) for 45 days resulted in significant changes in several biochemical parameters of the liver and serum of albino rats. After exposure to alcohol for 30 days when Picroliv (12 mg/kg, p.o.), an iridoid glycoside fraction of Picrorhiza kurroa, was administered for 15 days along with alcohol, the degree of change in most of the parameters was reduced.