Gene-activation mechanisms in the regression of atherosclerosis, elimination of diabetes type 2, and prevention of dementia.

Atherosclerotic vascular disease, diabetes mellitus (DM) and dementia are major global health problems. Both endogenous and exogenous factors activate genes functioning in biological processes. This review article focuses on gene-activation mechanisms that regress atherosclerosis, eliminate DM type 2 (DM2), and prevent cognitive decline and dementia. Gene-activating compounds upregulating functions of liver endoplasmic reticulum (ER) and affecting lipid and protein metabolism, increase ER size through membrane synthesis, and produce an antiatherogenic plasma lipoprotein profile. Numerous gene-activators regress atherosclerosis and reduce the occurrence of atherosclerotic disease. The gene-activators increase glucose disposal rate and insulin sensitivity and, by restoring normal glucose and insulin levels, remove metabolic syndrome and DM2. Patients with DM2 show an improvement of plasma lipoprotein profile and glucose tolerance together with increase in liver phospholipid (PL) and cytochrome (CYP) P450. The gene-activating compounds induce hepatic protein and PL synthesis, and upregulate enzymes including CYPs and glucokinase, nuclear receptors, apolipoproteins and ABC (ATP-binding cassette) transporters. They induce reparation of ER structures and eliminate consequences of ER stress. Healthy living habits activate mechanisms that maintain high levels of HDL and apolipoprotein AI, promote health, and prevent cognitive decline and dementia. Agonists of liver X receptor (LXR) reduce amyloid in brain plaques and improve cognitive performance in mouse models of Alzheimer's disease. The gene activation increases the capacity to withstand cellular stress and to repair cellular damage and increases life span. Life free of major health problems and in good cognitive health promotes well-being and living a long and active life.

Mitochondrial DNA polymerase gamma variants in idiopathic sporadic Parkinson disease.

OBJECTIVE: Dysfunction of mitochondrial DNA polymerase gamma (POLG) has been recently recognized as an important cause of inherited neurodegenerative diseases. We have reported dominant and recessive inheritance of parkinsonism, mitochondrial myopathy, and premature amenorrhea in five ethnically distinct families with POLG1 mutations. This prompted us to carry out a detailed analysis of the coding region and intron-exon boundaries of POLG1 in Finnish patients with idiopathic sporadic Parkinson disease (PD) and in nonparkinsonian controls. METHODS: The coding region of POLG1 was analyzed in 140 Finnish patients with PD and their 127 spouses as age- and ethnically matched controls. Further, we analyzed the intragenic CAG-repeat region of POLG1 in 126 additional patients with nonparkinsonian neurologic disorders and in 516 Finnish population controls. RESULTS: We found clustering of rare variants of the POLG1 CAG-repeat, encoding a polyglutamine tract, in Finnish patients with idiopathic PD as compared to their spouses (p = 0.003; OR 3.01, 95% CI 1.35 to 6.71), population controls (p = 0.001; OR 2.45, 95% CI 1.45 to 4.14), and patients with nonparkinsonian neurologic disorders (p = 0.05, OR 1.98, 95% CI 0.97 to 4.05). We found several amino acid substitutions, none of them associating with PD. These included a previously parkinsonism-associated POLG variant Y831C, found in one patient with PD, but also in five controls, suggesting that it is a neutral amino acid polymorphism. CONCLUSIONS: Our results suggest that POLG polyglutamine tract variants should be considered as a predisposing genetic factor in idiopathic sporadic Parkinson disease.

Do carriers of POLG mutation W748S have disease manifestations?

Mitochondrial recessive ataxia syndrome (MIRAS) is a common cause of autosomal recessive juvenile- or adult-onset ataxia, at least in Scandinavia. MIRAS patients are homozygous or compound heterozygous for POLG mutations W748S and A467T. Because many first-degree relatives of MIRAS patients in the studied families have reported neurological symptoms and some recent studies have suggested dominant negative effect of these mutations, a careful family study of heterozygotes was needed. We investigated all available members of the original large MIRAS family with W748S mutation. Neurological symptoms and signs were present in a number of carriers, but clearly defined neurological diseases did not segregate consistently with the mutation. Sensory polyneuropathy as a subclinical finding was observed in the majority of carriers examined. By positron emission tomography, cerebral glucose metabolism was moderately reduced in two out of four heterozygotes compared with severe reduction in one MIRAS patient. In conclusion, W748S heterozygotes showed no clinically manifesting phenotype.

POLG mutations in neurodegenerative disorders with ataxia but no muscle involvement.

OBJECTIVE: To identify POLG mutations in patients with sensory ataxia and CNS features. METHODS: The authors characterized clinical, laboratory, and molecular genetic features in eight patients from five European families. The authors conducted sequencing of coding exons of POLG, C10orf2 (Twinkle), and ANT1 and analyzed muscle mitochondrial DNA (mtDNA), including Southern blot analysis and long-range PCR. RESULTS: Ataxia occurred in combination with various CNS features, including myoclonus, epilepsy, cognitive decline, nystagmus, dysarthria, thalamic and cerebellar white matter lesions on MRI, and neuronal loss in discrete gray nuclei on autopsy. Gastrointestinal dysmotility, weight loss, cardiomyopathy, and valproate-induced hepatotoxicity occurred less frequently. Two patients died without preceding signs of progressive external ophthalmoplegia. In muscle, typical findings of mitochondrial disease, such as ragged red fibers and Southern blot mtDNA abnormalities, were absent. POLG mutations were present in eight patients, including two isolated cases, and one Finnish and two unrelated Belgian families contained in total six patients. All POLG mutations were recessive, occurring in a homozygous state in seven patients and in a compound heterozygous state in one patient. The novel W748S mutation was identified in five patients from three unrelated families. CONCLUSIONS: The clinical spectrum of recessive POLG mutations is expanded by sensory ataxic neuropathy, combined with variable features of involvement of CNS and other organs. Progressive external ophthalmoplegia, myopathy, ragged red fibers, and Southern blot abnormalities of muscle mitochondrial DNA also are not mandatory features associated with POLG mutations.

Two families with autosomal dominant progressive external ophthalmoplegia.

OBJECTIVES: We report here the clinical and genetic features of two new families with autosomal dominant progressive external ophthalmoplegia (adPEO). PATIENTS AND METHODS: The examination of index patients included a detailed clinical characterisation, histological analysis of muscle biopsy specimens, and genetic testing of mitochondrial and nuclear DNA extracted from muscle and leucocytes. RESULTS: Index patients in both families presented with PEO and developed other clinical disease manifestations, such as myopathy and cardiomyopathy (patient 1) and axonal neuropathy, diabetes mellitus, hearing loss, and myopathy (patient 2), later in the course of illness. Both patients had ragged red fibres on muscle histology. Southern blot of mtDNA from muscle of patient 2 showed multiple deletions. In this case, a novel heterozygous missense mutation F485L was identified in the nuclear encoded putative mitochondrial helicase Twinkle. The mutation co-segregated with the clinical phenotype in the family and was not detected in 150 control chromosomes. In the other index patient, sequencing of ANT1, C10orf2 (encoding for Twinkle), and POLG1 did not reveal pathogenic mutations. CONCLUSIONS: Our cases illustrate the clinical variability of adPEO, add a novel pathogenic mutation in Twinkle (F485L) to the growing list of genetic abnormalities in adPEO, and reinforce the relevance of other yet unidentified genes in mtDNA maintenance and pathogenesis of adPEO.

Serum lipid levels and M/L55 allele distribution of HDL paraoxonase gene in Saami and Finnish men.

Paraoxonase (PON) is an antioxidative enzyme, which eliminates lipid peroxides. The mutation in codon 55 of PON1 gene causes a change of methionine (M-allele) to leucine (L-allele) and influences PON activity. The Saami are a population living in the northern part of Fennoscandia. In previous studies their death rate from coronary artery disease (CAD) was found to be low. We compared PON M/L55 allele frequencies of 68 Saami and 68 Finnish men and related the PON genotypes to plasma lipid levels and to the levels of autoantibodies against oxidized LDL. The M/L55 genotypes were determined by PCR and restriction enzyme digestion. ELISA was used to measure antibodies against oxidized LDL. The L- and M-allele frequencies were 64% and 36% in Saami population and 64% and 36% in Finnish men, respectively (p = NS, Fisher's exact test). There were also no significant differences in plasma lipid levels or in antibody levels against oxidized LDL between PON genotypes or between Saami and Finnish men. Our results indicate that the PON M/L55 genotype is not associated with plasma lipid levels or the levels of autoantibodies against oxidized LDL in these populations. The Saami men have the same PON M/L55 allele distribution as the Finnish men and the PON genotype might thus not be one factor protecting Saami against CAD.

Antioxidants, infections and environmental factors in health and disease in northern Finland.

Recent studies have identified several factors which may affect human health and life expectancy in northern Finland. They have shown that antioxidants, infections, genetic or environmental factors may affect the development of and morbidity/mortality from cardiovascular diseases, cancer, diabetes mellitus and other diseases in the northern provinces of this country. Both the occurrence and mortality from coronary heart disease (CHD) is low in the northernmost part of the country, i.e. Mountain Lapland or the Saami area, compared with that in whole country or a neighbouring region to the south in central Lapland. The mortality from all diseases is also low in communities in Mountain Lapland, and high in central Lapland in communities such as Kittilä and Kolari. High scrum antioxidants, alpha-tocopherol (vitamin E), albumin and selenium levels have been measured in men living in the northernmost part of the country, where the death rate from CHD is low. Low serum alpha-tocopherol and albumin levels were typical of men living in rural communities with high CHD mortality, e.g. Kittilä community. Serum antioxidant levels were related to the diet; alpha-tocopherol increased with the consumption of reindeer meat and selenium with fish consumption. Our earlier studies have also identified a low Chlamydia pneumoniae IgA antibody titer in men living in Mountain Lapland compared with men in the neighboring region to the south in central Lapland with high CHD mortality. An elevated Chlamydia pneumoniae IgA antibody titer was associated with low serum alpha-tocopherol level. The people of Saami origin, an ethnic minority living in northernmost Finland, have a high apolipoprotein (apo) E e4 allele frequency and high serum cholesterol. They also have more apo A-IV-2 allele than most of the studied populations, and their HDL cholesterol levels are higher in apo A-IV-2/1 than in apo A-IV-1/1 phenotypes. Our earlier studies indicate that people living in northeastern Finland, west of smelters in Kola Peninsula may be exposed to heavy metals such as cadmium and mercury. Blood cadmium was related to blood pressure and high in men with arterial hypertensive disease. The investigations presented in this article form a good basis for further studies that clarify underlying reasons the health problems in the north.

Apolipoprotein A-IV polymorphism in Saami and Finns: frequency and effect on serum lipid levels.

Apolipoprotein A-IV (apoA-IV) is a glycoprotein constituent of triglyceride-rich and high-density lipoproteins (HDL) and may thus play an important role in lipid metabolism. In Finland two common isoforms (A-IV-1 and A-IV-2) of apoA-IV have been found. The isoforms are the result of the G to T substitution in the third base of the codon 360 in the apoA-IV-2 allele of the apoA-IV gene. The purpose of the study was to determine the apoA-IV allele frequencies in the Saami and the Finns, and to relate the apoA-IV phenotypes to serum lipids. The sample was drawn in connection with a Reindeer Herders' Health Survey performed in northern Finland in 1989. The study group included 248 men with known ethnic origin, Saami and Finns, who lived in the area of the nine northernmost municipalities of Finland. ApoA-IV phenotypes from 71 Saami (both parents Saami) and 177 Finns (both parents Finns) were determined by isoelectric focusing and Western blotting. Serum lipids were determined enzymatically. ApoA-IV allele frequencies in the Saami and the Finns were for A-IV-1 0.894 vs 0.944 and for A-IV-2 0.106 vs 0.056, respectively (chi2-test, P < 0.05). The effect of the apoA-IV phenotype on serum HDL-cholesterol levels differed significantly between the Saami and the Finns (two-way ANCOVA, interaction between ethnicity and apoA-IV phenotype, P < 0.02). In the Saami, HDL-cholesterol levels were significantly higher in the apoA-IV-2/1 than in the apoA-IV-1/1 phenotypes (ANCOVA, P < 0.05). Mean total cholesterol, low-density lipoprotein (LDL)-cholesterol, apolipoprotein B, HDL-cholesterol and triglyceride levels did not differ statistically significantly between the Saami and the Finns. Yet, there was a trend in the Saami of having higher mean total cholesterol, LDL-cholesterol and apolipoprotein B levels than the Finns among the apoA-IV-2/1 phenotypes, while there was only a small difference in these parameters between the Saami and the Finns among the apoA-IV-1/1 phenotypes. In conclusion, the Saami have a higher frequency of the apoA-IV-2 allele than the Finns and most of the other studied populations.

Gene activation, apolipoprotein A-I/high density lipoprotein, atherosclerosis prevention and longevity.

Recent studies in man and human apolipoprotein A-I transgenic animals emphasize the significance of apolipoprotein A-I and high density lipoprotein in antiatherogenesis. Several drugs and other compounds, e.g. phenobarbital, gemfibrozil, fenofibrate, prednisone, estrogen and alcohol, induce apolipoprotein A-I synthesis. They commonly produce serum lipoprotein patterns typical of a low risk of coronary heart disease, and many of them have been found to prevent atherogenesis, reduce coronary heart disease mortality and increase survival. These compounds act against atherosclerosis by using one or several mechanisms that include overexpression of the apolipoprotein A-I gene with an increase in serum apolipoprotein A-I and high density lipoprotein and promotion of reverse cholesterol transport, upregulation of the low density lipoprotein receptor gene with a decrease in serum apolipoprotein B and low density lipoprotein, maintenance of endothelial cell function and protection against thrombosis. They have been found to raise high density lipoprotein cholesterol and apolipoprotein A-I together with a decrease in cholesterol ester transfer protein activity, and to induce hepatic cholesterol 7 alpha-hydroxylase and cholesterol and bile acid elimination from the body. By raising the activities of apolipoprotein A-I/high density lipoprotein-associated paraoxonase and other antioxidative enzymes, the inducers have the capacity to prevent atherogenesis in arterial walls through inhibition of the oxidative modification of low density lipoprotein. Other antiatherogenic vascular actions of high density lipoprotein include interference with low density lipoprotein aggregation and uptake by endothelial cells, and competition with low density lipoprotein for endothelial-localized low density lipoprotein receptors. Apolipoprotein A-I/high density lipoprotein beneficially enhances fibrinolysis, decreases platelet aggregation, increases prostacyclin production and stabilization and prevents atherogenic immune and inflammatory responses. This gene activation or microsomal induction can prevent atherosclerosis and is a basis for tailoring effective new agents and optimal non-invasive therapy against atherosclerotic vascular disease to promote health and enhance longevity.

High serum alpha-tocopherol, albumin, selenium and cholesterol, and low mortality from coronary heart disease in northern Finland.

OBJECTIVES: The mortality from coronary heart disease (CHD) is exceptionally low in northernmost Finland, the Sámi (formerly known as Lapp) area. To clarify the reasons for this, the levels of serum cholesterol, other classic risk factors, and major antioxidants, alpha-tocopherol, retinol, albumin and selenium were determined in males living in the low-mortality area and in a reference area. DESIGN: A health survey amongst reindeer herdsmen living in the three northernmost communes of Finland (the Sámi area) and in the six neighbouring communities to the south (the reference area). The mortality from CHD in the two areas was determined from death certificates issued during the period 1981-1990. SUBJECTS: A total of 350 participants of the health survey, mean age 46 (SD 14) years. RESULTS: The mortality from CHD was 17% lower in the Sámi area than in the reference area [95% confidence interval (CI) for the difference: 4-29]. Subjects living in the low-mortality area showed higher serum-lipid-adjusted alpha-tocopherol (18.4 vs. 16.1 mumol L-1; 95% CI for difference: 0.7-3.9; P < 0.001), albumin (46.9 vs. 46.2 g L-1; 0.2-1.3; P < 0.02), selenium (1.59 vs. 1.47 mumol L-1; 0.02-0.22; P < 0.02), cholesterol (6.76 vs. 6.34 mmol L-1; 0.12-0.72; P < 0.001) and LDL cholesterol (4.76 vs. 4.45 mmol L-1; 0.05-0.57; P < 0.02) than those in the reference area. The HDL cholesterol:cholesterol ratio was lower in the Sámi area than in the reference area (0.20 vs. 0.21; -0.02-0.00; P < 0.04). The Sámis showed higher serum selenium than the Finns. Serum alpha-tocopherol increased with the consumption of reindeer meat and serum selenium increased with fish consumption. CONCLUSIONS: Alpha-tocopherol, albumin and selenium may play a role in the low mortality from CHD observed in northernmost Finland. The favourable serum antioxidant status in northerners may be credited to the local diet.

Association of blood cadmium to the area of residence and hypertensive disease in Arctic Finland.

The association of cadmium exposure with area of residence, blood pressure, and arterial hypertensive disease was examined in 230 reindeer herders in northernmost arctic Finland. Blood cadmium concentration averaged 10.0 nmol/l, and was three times higher in smokers than in nonsmokers (16.7 vs. 5.5 nmol/l). Concentrations increased from the southwestern to the northeastern area west of the Kola Peninsula, Russia, both in nonsmokers (3.1 vs. 6.8 nmol/l) and smokers (10.8 vs. 32.0 nmol/l). High cadmium levels were most common in the northeast: 32% of the values were at least 15 nmol/l, 10% at least 45 nmol/l (health-based limit of WHO), and 3% at least 90 nmol/l (the critical limit for renal damage). High cadmium concentration was associated with a rise in blood pressure; the rise was particularly pronounced in subjects with hypertensive diseases. These associations were not affected by age, body mass index, smoking, and alcohol consumption. The results suggest that cadmium exposure may have harmful health effects in arctic Finland and emphasize the importance of reducing pollution from industrial sources in the Kola Peninsula.

High serum concentrations of vitamin E and cholesterol and low mortality from ischaemic heart disease in northern Finland.

The regional mortality from ischaemic heart disease varies from low to high in northern Finland. To clarify the reasons for this 361 men engaged in reindeer herding who lived in the northernmost part of the country, the Sámi area, or a neighbouring reference area were investigated. The mortality from IHD in the general population was lower in the Sámi area than the reference area. The serum lipid-adjusted vitamin E (alpha tocopherol) and cholesterol showed reverse trends, being higher in the Sámi area. Serum vitamin E increased with the consumption of reindeer meat. A diet-associated good vitamin E status may be one factor in the anomalous, low mortality from IHD in the North in a population with high serum cholesterol.

Blood mercury and serum selenium concentrations in reindeer herders in the arctic area of northern Finland.

163 healthy reindeer herders living in the arctic area of northern Finland were investigated for blood mercury and serum selenium concentrations. More than ten percent of the subjects had blood mercury above the upper normal limit. High organic and total organic mercury levels were most common in the northeastern part of the country. High organic and total mercury and selenium values were more common in the Lapps than the Finns. Blood mercury levels increased with increasing fish consumption. The pollution in the northeastern part of this country probably leads to the increased formation of organic mercury, and its enrichment in the food chain. The association of high selenium with high mercury probably reduces the toxicity of the latter.

Lipid peroxides, glutathione peroxidase, high density lipoprotein subfractions and apolipoproteins in young adults.

Lipid peroxides have been implicated in the initiation of atherogenesis. In this study of 23 young healthy subjects, high levels of serum lipid peroxides were associated with low serum HDL2 cholesterol concentrations and low HDL2/HDL3 cholesterol and apolipoprotein A-I/A-II ratios. Low levels of LDL cholesterol and apolipoprotein B, and low apolipoprotein B/A-I ratios were typical of subjects with high serum glutathione peroxidase activities. Serum lipid peroxide levels varied widely in subjects without abnormal cholesterol, HDL cholesterol or LDL cholesterol concentrations. This variation may play a role in the frequent occurrence of coronary artery disease in normolipidaemic individuals.

High-density lipoprotein subfractions, apolipoproteins and antipyrine clearance in normal subjects.

Serum high density lipoprotein (HDL) subfractions HDL2 and HDL3, apolipoproteins, and plasma antipyrine clearance (AP-CL) rate, an index of liver microsomal enzyme activity, were determined in 21 healthy subjects. High HDL cholesterol and HDL2 cholesterol concentrations and HDL cholesterol/cholesterol and HDL2/HDL3 cholesterol ratios were associated with high AP-CL. Phenobarbital enhanced antipyrine elimination and increased the apolipoprotein A-I/A-II ratio. Subjects who had high AP-CL had a more antiatherogenic HDL subfraction and apolipoprotein profile than those with low AP-CL.

Nucleic acid sandwich hybridization: enhanced reaction rate with magnetic microparticles as carriers.

A method for the detection of nucleic acid hybrids using the sandwich hybridization technique with magnetic polystyrene microparticles as the solid support is described. The capture DNA is coupled to the polystyrene-hydroxy surface of the particles through p-toluenesulfonyl chloride activation. The use of microparticles results in a substantial increase in the reaction rate compared to filter hybridization, without decreasing the sensitivity of detection. Polyethylene glycol additionally enhances the reaction rate. The use of magnetic microparticles allows rapid and convenient collection of the formed hybrids.

The effects of phenobarbital on serum high density lipoprotein subfractions and apolipoproteins.

Prospective studies report that a pharmacologic elevation of serum high density lipoprotein (HDL) concentration may be of value in the prevention of atherosclerosis. In this study phenobarbital, 50 mg at bedtime for ten days, increased serum HDL cholesterol, HDL2 cholesterol and HDL cholesterol/cholesterol and HDL cholesterol/apolipoprotein A-I ratios. Phenobarbital treated subjects had serum lipoprotein profile typical of low risk of ischemic heart disease.

Microsomal enzyme induction, lipoproteins and atherosclerosis.

The liver is the principal site for the synthesis and elimination of lipoproteins circulating in plasma, and alterations in hepatic function influence plasma lipoprotein levels. High HDL-C/T-C and apo A-I/apo B ratios, which are characteristic of a low coronary risk, have been typical of healthy subjects with high microsomal enzyme activity in the liver. Microsomal enzyme inducing drugs such as phenytoin, phenobarbital and carbamazepine, and also alcohol, influence serum lipid and apoprotein concentrations. The inducers increase the concentrations of hepatic microsomal enzyme and apo A-I mRNA, and also proteins and phospholipids. They similarly increase serum HDL-C and apo A-I levels and the HDL-C/LDL-C ratio, powerful protective factors against coronary heart disease. These parameters parallel hepatic protein and phospholipid concentrations, and microsomal enzyme activity as assessed by liver cytochrome P-450 or antipyrine kinetics. Serum LDL-C levels are inversely proportional to hepatic cytochrome P-450 concentrations. Experimental studies indicate that phenobarbital retards cholesterol accumulation in the arterial wall and the formation of atherosclerotic plaque. A decreased mortality rate from coronary heart disease has been reported for subjects who take enzyme inducers, drugs or alcohol, whereas impairment of hepatic microsomal function may promote atherogenesis. In addition to drugs non-pharmacological factors such as dietary constituents and physical exercise may influence hepatic microsomal function and hence improve the serum lipoprotein profile. These observations, which connect microsomal inducers, liver lipids and proteins, serum lipids and apoproteins characteristic of a low risk of atherosclerotic disease and low incidence of coronary deaths, lead to the conclusion that the activation of liver microsomal function can prevent atherogenesis in man.