Lipoprotein signatures of cholesteryl ester transfer protein and HMG-CoA reductase inhibition

Cholesteryl ester transfer protein (CETP) inhibition reduces vascular event risk, but confusion surrounds its effects on low-density lipoprotein (LDL) cholesterol. Here, we clarify associations of genetic inhibition of CETP on detailed lipoprotein measures and compare those to genetic inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR). We used an allele associated with lower CETP expression (rs247617) to mimic CETP inhibition and an allele associated with lower HMGCR expression (rs12916) to mimic the well-known effects of statins for comparison. The study consists of 65,427 participants of European ancestries with detailed lipoprotein subclass profiling from nuclear magnetic resonance spectroscopy. Genetic associations were scaled to 10% reduction in relative risk of coronary heart disease (CHD). We also examined observational associations of the lipoprotein subclass measures with risk of incident CHD in 3 population-based cohorts totalling 616 incident cases and 13,564 controls during 8-year follow-up. Genetic inhibition of CETP and HMGCR resulted in near-identical associations with LDL cholesterol concentration estimated by the Friedewald equation. Inhibition of HMGCR had relatively consistent associations on lower cholesterol concentrations across all apolipoprotein B-containing lipoproteins. In contrast, the associations of the inhibition of CETP were stronger on lower remnant and very-low-density lipoprotein (VLDL) cholesterol, but there were no associations on cholesterol concentrations in LDL defined by particle size (diameter 18–26 nm) (−0.02 SD LDL defined by particle size; 95% CI: −0.10 to 0.05 for CETP versus −0.24 SD, 95% CI −0.30 to −0.18 for HMGCR). Inhibition of CETP was strongly associated with lower proportion of triglycerides in all high-density lipoprotein (HDL) particles. In observational analyses, a higher triglyceride composition within HDL subclasses was associated with higher risk of CHD, independently of total cholesterol and triglycerides (strongest hazard ratio per 1 SD higher triglyceride composition in very large HDL 1.35; 95% CI: 1.18–1.54). In conclusion, CETP inhibition does not appear to affect size-specific LDL cholesterol but is likely to lower CHD risk by lowering concentrations of other atherogenic, apolipoprotein B-containing lipoproteins (such as remnant and VLDLs). Inhibition of CETP also lowers triglyceride composition in HDL particles, a phenomenon reflecting combined effects of circulating HDL, triglycerides, and apolipoprotein B-containing particles and is associated with a lower CHD risk in observational analyses. Our results reveal that conventional composite lipid assays may mask heterogeneous effects of emerging lipid-altering therapies.

Inhibition of cholesteryl ester transfer protein does not affect size-specific low-density lipoprotein cholesterol, but may lower coronary heart disease risk by lowering cholesterol concentrations in other apolipoprotein-B containing atherogenic lipoproteins, and by lowering triglyceride content of high-density lipoprotein particles.

Randomized controlled trial comparing the efficacy of daily and every other day atorvastatin therapy and its correlation with serum hydroxymethylglutaryl-CoA reductase enzyme levels in naïve dyslipidemic patients

Objective

Data regarding efficacy comparison of daily regimen (DR) versus every other day regimen (EODR) atorvastatin therapy is not validated by estimation of serum hydroxymethylglutaryl-CoA reductase (HMGCR) levels and HMGCR correlation with lipid indices.

Methods

In this randomized controlled trial, we compared the efficacy of DR versus EODR by measuring lipid indices and serum HMGCR levels at baseline and after 12 weeks of 10 mg atorvastatin therapy. Primary endpoint was comparison of mean change in serum HMGCR levels and lipid indices of both groups and their correlation with each other. Secondary endpoints were assessed by estimating serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatine kinase MM (CK-MM) levels and adverse drug reactions (ADRs).

Results

A total of 61 patients were enrolled of which 46 completed the study (24 in DR vs 22 in EODR group). The mean reduction in total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and non-high density lipoprotein-cholesterol (HDL-C) was significantly higher in DR group, whereas mean reduction in triglycerides (TG) and increase in HDL-C was similar in both the groups. Reduction in serum HMGCR levels was comparable in both the groups (31.17% vs 28.19%). Change in serum HMGCR levels correlated more with change in lipid indices of DR group. Also, safety parameters were similar between the two groups.

Conclusion

Both the regimens achieved therapeutic goals, however DR was found to be superior as it achieved greater reduction in TC and LDL-C. Further, these findings are substantiated by correlation of lipid indices with serum HMGCR levels.

ISOPRENOID PATHWAY-RELATED MEMBRANE DYSFUNCTION IN NEUROPSYCHIATRIC DISORDERS

The membrane composition and the isoprenoid pathway metabolites important in maintaining cell membrane integrity was studied in neurological and psychiatric disorders. The results indicate alteration in cholesterol:phospholipid ratio of the RBC membrane which is increased in glioma, schizophrenia, and bipolar mood disorder (MDP); decreased in multiple sclerosis and Parkinson's disease; and not significantly altered in epilepsy. The concentration of total glycosaminoglycans (GAG), hexose, and fucose decreased in the RBC membrane and increased in the serum. The RBC membrane Na+-K+ ATPase activity was reduced and serum HMG CoA reductase activity was increased. There were increased serum levels of digoxin, cholesterol, and dolichol and decreased levels of ubiquinone. The serum magnesium and tyrosine levels were reduced and tryptophan increased. The results indicate a defect in membrane formation and a decreased membrane Na+-K+ ATPase activity in all the disorders studied. The results are discussed, and a hypothesis regarding the relationship between these disorders and defective membrane architecture and membrane Na+-K+ ATPase inhibition is presented.

SCHIZOID NEUROCHEMICAL PATHOLOGY-INDUCED MEMBRANE NA+-K+ ATPASE INHIBITION IN RELATION TO NEUROLOGICAL DISORDERS

Psychiatric abnormalities have been described in primary neurological disorders like multiple sclerosis, primary generalized epilepsy, Parkinson's disease, subacute sclerosing panencephalitis (SSPE), central nervous system glioma, and syndrome X with vascular dementia. It was therefore considered pertinent to compare monoamine neurotransmitter pattern in schizophrenia with those in the disorders described above. The end result of neurotransmission is changes in membrane Na(+)-K+ ATPase activity. Membrane Na(+)-K+ ATPase inhibition can lead to magnesium depletion, which can lead to an upregulated isoprenoid pathway. The isoprenoid pathway produces three important metabolites--digoxin, an endogenous membrane Na(+) -K+ ATPase inhibitor; ubiquinone, a membrane antioxidant and component of mitochondrial electron transport chain; and dolichol, important in N-glycosylation of protein. The serum/plasma levels of digoxin, dolichol, ubiquinone, magnesium, HMG CoA reductase activity, and RBC Na(+)-K+ ATPase activity were estimated in all these disorders. The result showed that the concentration of serum tryptophan and serotonin was high and serum tyrosine, dopamine, adrenaline, and noradrenaline low in all the disorders studied. The plasma HMG CoA reductase activity, serum digoxin, and serum dolichol levels were high and serum ubiquinone levels, serum magnesium, and RBC Na(+)-K+ ATPase activity were low in all the disorders studied. The significance of these changes in the pathogenesis of syndrome X, multiple sclerosis, primary generalized epilepsy, schizophrenia, SSPE, and Parkinson's disease is discussed in the setting of the interrelationship between these disorders documented in literature.

Evaluation of the potential for steady-state pharmacokinetic interaction between vildagliptin and simvastatin in healthy subjects

BACKGROUND

Vildagliptin is an orally active, potent and selective inhibitor of dipeptidyl peptidase IV (DPP-4), the enzyme responsible for the degradation of incretin hormones. By enhancing prandial levels of incretin hormones, vildagliptin improves glycemic control in type 2 diabetes. Co-administration of vildagliptin and simva statin, an HMG-CoA-reductase inhibitor may be required to treat patients with diabetes and dyslipidemia. There fore, this study was conducted to determine the potential for pharmacokinetic drug-drug interaction between vildagliptin and simvastatin at steady-state.

METHODS

An open label, single center, multiple dose, three period, crossover study was conducted in 24 healthy subjects. All subjects received once daily doses of either vildagliptin 100 mg or simvastatin 80 mg or the combination for 7 days with an inter-period washout of 7 days. Plasma levels of vildagliptin, simvastatin, and its active metabolite, simvastatin beta-hydroxy acid (major active metabolite of simvastatin) were determined using validated LC/MS/MS methods. Pharmacokinetic and statistical analyses were performed using WinNonlin and SAS, respectively.

RESULTS

The 90% confidence intervals of C(max) and AUC(tau) of vildagliptin, simvastatin, and simvastatin beta-hydroxy acid were between 80 and 125% (bioequivalence range) when vildagliptin and simvastatin were admin istered alone and in combination. These data indicate that the rate and extent of absorption of vildagliptin and simvastatin were not affected when co-administered, nor was the metabolic conversion of simvastatin to its active metabolite. All treatments were safe and well tolerated in this study.

CONCLUSIONS

The pharmacokinetics of vildagliptin, simvastatin, and its active metabolite were not altered when vildagliptin and simvastatin were co-administered.

Hypocholesterolemic and antioxidant properties of 3-(4-hydroxyl)propanoic acid derivatives in high-cholesterol fed rats

The purpose of the present study was to evaluate the in vivo efficacy of two cinnamic acid synthetic derivatives (allyl 3-[4-hydroxyphenyl]propanoate; HPP304, 1-naphthyl-methyl 3-[4-hydroxyphenyl]propanoate; HPP305) in high-cholesterol fed rats and compare their actions to that of cinnamic acid. Cinnamic acid and its synthetic derivatives were supplemented with a high-cholesterol diet for 42 days at a dose of 0.135 mmol/100g of diet. The supplementation of HPP304 and HPP305 significantly lowered cholesterol and triglyceride levels in the plasma and liver with a simultaneous increase in the HDL-cholesterol concentration, whereas cinnamic acid only lowered the plasma cholesterol concentration. Cinnamic acid lowered hepatic HMG-CoA reductase activity in high-cholesterol fed rats, however, its synthetic derivatives (HPP304 and HPP305) did not affect HMG-CoA reductase activity compared to the control group. Instead, the HPP304 and HPP305 supplements significantly lowered hepatic acyl coenzyme A:cholesterol acyltransferase activity and increased the fecal bile acid. The SOD activity of the erythrocytes and liver was not different between the groups, however, the activities of CAT and GSH-Px, and the level of GSH in the erythrocytes were significantly higher in the HPP304 and HPP305 groups than in the control group. On the other hand, the activities of CAT and GSH-Px, and the level of malondialdehyde in the liver were significantly lower in the HPP304 and HPP305 groups. The antioxidant activities of these cinnamic acid synthetic derivatives were similar to the cinnamic acid in the high-cholesterol fed rats. In addition, HPP304 and HPP305 lowered amniotransferase activity in the plasma. These results suggest that two cinnamic acid synthetic derivatives (HPP304 and HPP305) exert lipid-lowering action and antioxidant properties without hepatotoxicity in high-cholesterol fed rats.

Hypocholesterolemic and antioxidative effects of naringenin and its two metabolites in high-cholesterol fed rats

This study was conducted to compare the hypocholesterolemic and antioxidant effects of naringenin (0.02%), and its metabolites, rho-hyproxyphenylpropionic acid (PHPP, 0.012%) and rho-hydroxybenzoic acid (PHB, 0.012%), in 1% cholesterol diet-fed rats. All supplements significantly lowered the plasma total-cholesterol (total-C), triglyceride (TG) and atherogenic index, and hepatic cholesterol levels compared with the control group. The plasma high-density lipoprotein-cholesterol (HDL-C) concentration was significantly higher in these supplemented groups. However, PHB group only affected the reduction of hepatic TG content. The hydroxyl-3-methylglutaryl-coenzyme A reductase (HMGR) activity was significantly lower in all supplemented groups, whereas only the naringenin group reduced the acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity compared with the control group. The fecal acidic sterol excretion and hepatic superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were significantly higher in all supplemented groups. All supplements also significantly decreased the contents of plasma and hepatic thiobarbituric acid reactive substances (TBARS). Accordingly, it was considered that naringenin and its metabolites were effective on improving the cholesterol and antioxidant metabolism.

Antihyperlipidemic Effect ofScoparia dulcis(Sweet Broomweed) in Streptozotocin Diabetic Rats

We have investigated Scoparia dulcis, an indigenous plant used in Ayurvedic medicine in India, for its possible antihyperlipidemic effect in rats with streptozotocin-induced experimental diabetes. Oral administration of an aqueous extract of S. dulcis plant (200 mg/kg of body weight) to streptozotocin diabetic rats for 6 weeks resulted in a significant reduction in blood glucose, serum and tissue cholesterol, triglycerides, free fatty acids, phospholipids, 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase activity, and very low-density lipoprotein and low-density lipoprotein cholesterol levels. The decreased serum high-density lipoprotein cholesterol, anti-atherogenic index, and HMG-CoA reductase activity in diabetic rats were also reversed towards normalization after the treatment. Similarly, the administration of S. dulcis plant extract (SPEt) to normal animals resulted in a hypolipidemic effect. The effect was compared with glibenclamide (600 microg/kg of body weight). The results showed that SPEt had antihyperlipidemic action in normal and experimental diabetic rats in addition to its antidiabetic effect.

Simvastatin does not have a clinically significant pharmacokinetic interaction with fenofibrate in humans

Simvastatin and fenofibrate are both commonly used lipid-regulating agents with distinct mechanisms of action, and their coadministration may be an attractive treatment for some patients with dyslipidemia. A 2-period, randomized, open-label, crossover study was conducted in 12 subjects to determine if fenofibrate and simvastatin are subject to a clinically relevant pharmacokinetic interaction at steady state. In treatment A, subjects received an 80-mg simvastatin tablet in the morning for 7 days. In treatment B, subjects received a 160-mg micronized fenofibrate capsule in the morning for 7 days, followed by a 160-mg micronized fenofibrate capsule dosed together with an 80-mg simvastatin tablet on days 8 to 14. Because food increases the bioavailability of fenofibrate, each dose was administered with food to maximize the exposure of fenofibric acid. The steady-state pharmacokinetics (AUC(0-24h), C(max), and t(max)) of active and total HMG-CoA reductase inhibitors, simvastatin acid, and simvastatin were determined following simvastatin administration with and without fenofibrate. Also, fenofibric acid steady-state pharmacokinetics were evaluated with and without simvastatin. The geometric mean ratios (GMRs) for AUC(0-24h) (80 mg simvastatin [SV] + 160 mg fenofibrate)/(80 mg simvastatin alone) and 90% confidence intervals (CIs) were 0.88 (0.80, 0.95) and 0.92 (0.82, 1.03) for active and total HMG-CoA reductase inhibitors. The GMRs and 90% CIs for fenofibric acid (80 mg SV + 160 mg fenofibrate/160 mg fenofibrate alone) AUC(0-24h) and C(max) were 0.95 (0.88, 1.04) and 0.89 (0.77, 1.02), respectively. Because both the active inhibitor and fenofibric acid AUC GMR 90% confidence intervals fell within the prespecified bounds of (0.70, 1.43), no clinically significant pharmacokinetic drug interaction between fenofibrate and simvastatin was concluded in humans. The coadministration of simvastatin and fenofibrate in this study was well tolerated.

Hypothalamic digoxin, hemispheric chemical dominance, and mesenteric artery occlusion

The role of the isoprenoid pathway in vascular thrombosis, especially mesenteric artery occlusion and its relation to hemispheric dominance, was assessed in this study. The following parameters were measured in patients with mesenteric artery occlusion and individuals with right hemispheric, left hemispheric, and bihemispheric dominance: (1) plasma HMG CoA reductase, digoxin, dolichol, ubiquinone, and magnesium levels; (2) tryptophan/tyrosine catabolic patterns; (3) free radical metabolism; (4) glycoconjugate metabolism; and (5) membrane composition. In patients with mesenteric artery occlusion there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels, low ubiquinone, and elevated free radical levels. The RBC membrane Na(+)-K+ ATPase activity and serum magnesium were decreased. There was also an increase in tryptophan catabolites and reduction in tyrosine catabolites in the serum. There was an increase in cholesterol:phospholipid ratio and a reduction in glycoconjugate level of RBC membrane in these patients. The biochemical patterns obtained in mesenteric artery occlusion is similar to those obtained in left-handed/right hemispheric dominant individuals by the dichotic listening test. But all the patients with mesenteric artery occlusion were right-handed/left hemispheric dominant by the dichotic listening test. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test. Mesenteric artery occlusion occurs in right hemispheric chemically dominant individuals and is a reflection of altered brain function. Hemispheric chemical dominance may thus control the risk for developing vascular thrombosis in individuals.

Hypothalamic-mediated model for systemic lupus erythematosis: relation to hemispheric chemical dominance

The isoprenoid pathway including endogenous digoxin was assessed in systemic lupus erythematosis (SLE). All the patients with SLE were right-handed/left hemispheric dominant by the dichotic listening test. This was also studied for comparison in patients with right hemispheric and left hemispheric dominance. The isoprenoid pathway was upregulated with increased digoxin synthesis in patients with SLE and in those with right hemispheric dominance. In this group of patients (i) the tryptophan catabolites were increased and the tyrosine catabolites reduced, (ii) the dolichol and glycoconjugate levels were elevated, (iii) lysosomal stability was reduced, (iv) ubiquinone levels were low and free radical levels increased, and (v) the membrane cholesterol:phospholipid ratios were increased and membrane glycoconjugates reduced. On the other hand, in patients with left hemispheric dominance the reverse patterns were obtained. The biochemical patterns obtained in SLE is similar to those obtained in left-handed/right hemispheric chemically dominant individuals. But all the patients with SLE were right-handed/left hemispheric dominant by the dichotic listening test. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test. SLE occurs in right hemispheric chemically dominant individuals, and is a reflection of altered brain function. The role of the isoprenoid pathway in the pathogenesis of SLE and its relation to hemispheric dominance is discussed.

Endogenous hypodigoxinemia-related immune deficiency syndrome

The isoprenoid pathway produces three key metabolites--digoxin (membrane Na+-K+ ATPase inhibitor, regulator of neurotransmitter transport, and an immunomodulatory agent), dolichol (a regulator of N-glycosylation of proteins), and ubiquinone (a free radical scavenger). The pathway was assessed in acute rheumatic fever patients with recurrent streptococcal infections, and who were also studied for differences in right and left hemispheric dominance. The isoprenoid pathway was downregulated with decreased digoxin synthesis in these patients and in those with left hemispheric chemical dominance. The tryptophan catabolites were decreased and the tyrosine catabolites increased. In these groups of patients the dolichol and glycoconjugate levels were reduced and lysosomal stability was increased. The ubiquinone levels were elevated and free radical levels decreased in these patients. The membrane cholesterol:phospholipid ratios were decreased and membrane glycoconjugates increased. On the other hand in right hemispheric chemical dominance the reverse patterns and hyperdigoxinemia with an upregulated isoprenoid pathway were noticed. The role of the isoprenoid pathway in the pathogenesis of acute rheumatic fever and recurrent streptococcal infections and its relation to hemispheric chemical dominance is discussed.

Hypothalamic digoxin-mediated model for trisomy 21

The isoprenoid pathway related cascade was assessed in trisomy 21. Membrane Na+, K(+)-ATPase activity, serum magnesium, and ubiquinone were decreased while hydroxy methyl glutaryl CoA (HMG) coenzyme A (CoA) reductase activity, serum digoxin, and dolichol levels were increased in trisomy 21. There were increased levels of tryptophan catabolites--nicotine, strychnine, quinolinic acid, and serotonin--and decreased levels of tyrosine catabolites--dopamine, noradrenaline, and morphine in trisomy 21. There was an increase in dolichol levels, carbohydrate residues of glycoproteins, glycolipids, total/individual glycosaminoglycan (GAG) fractions, and lysosomal enzymes in trisomy 21. Reduced levels of ubiquinone, reduced glutathione, and free radical scavenging enzymes as well as increased lipid peroxidation products and nitric oxide were noticed in trisomy 21. Hypothalamic digoxin and a disordered isoprenoid pathway are important in the pathogenesis of trisomy 21.

Hypothalamic digoxin, hemispheric chemical dominance, and chronic bronchitis emphysema

The isoprenoid pathway produces three key metabolites--endogenous digoxin (membrane sodium-potassium ATPase inhibitor, immunomodulator, and regulator of neurotransmitter/amino acid transport), dolichol (regulates N-glycosylation of proteins), and ubiquinone (free radical scavenger). This was assessed in patients with chronic bronchitis emphysema. The pathway was also assessed in patients with right hemispheric, left hemispheric, and bihemispheric dominance to find the role of hemispheric dominance in the pathogenesis of chronic bronchitis emphysema. All the 15 patients with chronic bronchitis emphysema were right-handed/left hemispheric dominant by the dichotic listening test. In patients with chronic bronchitis emphysema there was elevated digoxin synthesis, increased dolichol, and glycoconjugate levels, and low ubiquinone and elevated free radical levels. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites. There was an increase in cholesterol:phospholipid ratio and a reduction in glycoconjugate levels of RBC membrane in patients with chronic bronchitis emphysema. The same biochemical patterns were obtained in individuals with right hemispheric dominance. Endogenous digoxin by activating the calcineurin signal transduction pathway of T-cell can contribute to immune activation in chronic bronchitis emphysema. Increased free radical generation can also lead to immune activation. Endogenous synthesis of nicotine can contribute to the pathogenesis of the disease. Altered glycoconjugate metabolism and membranogenesis can lead to defective lysosomal stability contributing to the disease process by increased release of lysosomal proteases. The role of an endogenous digoxin and hemispheric dominance in the pathogenesis of chronic bronchitis emphysema and in the regulation of lung structure/function is discussed. The biochemical patterns obtained in chronic bronchitis emphysema is similar to those obtained in left-handed/right hemispheric chemically dominant individuals by the dichotic listening test. But all the patients with chronic bronchitis emphysema were right-handed/left hemispheric dominant by the dichotic listening test. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test. Chronic bronchitis emphysema occurs in right hemispheric chemically dominant individuals and is a reflection of altered brain function. Hemispheric chemical dominance can play a role in the regulation of lung function and structure.

The isoprenoid pathway and the pathogenesis of Reye's syndrome

The isoprenoid pathway produces three key metabolites: endogenous digoxin (regulator of neurotransmitter uptake), dolichol, and ubiquinone (free radical scavenger). Since a mitochondrial dysfunction has been described in Reye's syndrome, it was considered pertinent to assess the pathway in this disease. Since endogenous digoxin can regulate neurotransmitter transport, the pathway was also assessed in patients with right hemispheric, left hemispheric, and bihemispheric dominance to find out the role of hemispheric dominance in its pathogenesis. The plasma/serum activity of hydroxy methyl glutaryl (HMG) coenzyme A (CoA) reductase, magnesium, digoxin, dolichol, ubiquinone, tryptophan/tyrosine catabolic patterns, and free radical and lipid levels, as well as RBC Na+, K(+)-ATPase activity, were measured in the groups mentioned.

RESULTS

In the patient group as well as in individuals with right hemispheric dominance similar patterns were obtained. There was elevated digoxin and dolichol levels with low levels of ubiquinone in patients with Reye's syndrome as well as in those with right hemispheric dominance. The serum magnesium and RBC Na+, K(+)-ATPase activity were reduced. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites as well as increased free radical levels. Reye's syndrome is associated with an upregulated isoprenoid pathway, elevated hypothalamic digoxin secretion, and right hemispheric chemical dominance.

Hypothalamic digoxin, hemispheric chemical dominance, and inflammatory bowel disease

The isoprenoid pathway produces three key metabolites--endogenous digoxin, dolichol, and ubiquinone. It was considered pertinent to assess the pathway in inflammatory bowel disease (ulcerative colitis and regional ileitis). Since endogenous digoxin can regulate neurotransmitter transport, the pathway and the related cascade were also assessed in individuals with differing hemispheric dominance to find out the role of hemispheric dominance in its pathogenesis. All the patients with inflammatory bowel disease were right-handed/left hemispheric dominant by the dichotic listening test. The following parameters were measured in patients with inflammatory bowel disease and in individuals with differing hemispheric dominance: (1) plasma HMG CoA reductase, digoxin, dolichol, ubiquinone, and magnesium levels; (2) tryptophan/tyrosine catabolic patterns; (3) free-radical metabolism; (4) glycoconjugate metabolism; and (5) membrane composition and RBC membrane Na+-K+ ATPase activity. Statistical analysis was done by ANOVA. In patients with inflammatory bowel disease there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels, and low ubiquinone and elevated free radical levels. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites. There was an increase in cholesterol:phospholipid ratio and a reduction in glycoconjugate level of RBC membrane in these groups of patients. Inflammatory bowel disease is associated with an upregulated isoprenoid pathway and elevated digoxin secretion from the hypothalamus. This can contribute to immune activation, defective glycoprotein bowel antigen presentation, and autoimmunity and a schizophreniform psychosis important in its pathogenesis. The biochemical patterns obtained in inflammatory bowel disease is similar to those obtained in left-handed/right hemispheric dominant individuals by the dichotic listening test. But all the patients with peptic ulcer disease were right-handed/left hemispheric dominant by the dichotic listening test. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test. Inflammatory bowel disease occurs in right hemispheric chemically dominant individuals and is a reflection of altered brain function.

Hypothalamic digoxin, cerebral chemical dominance, and nitric oxide synthesis

The biochemical differences between right hemispheric dominant and left hemispheric dominant individuals are assessed with regard to nitric oxide synthesis. Nitric oxide is an important neurotransmitter involved in erectile function. The following parameters were evaluated: the plasma HMG CoA reductase activity, isoprenoid metabolite-digoxin, plasma magnesium and RBC membrane Na(+)-K(+) ATPase activity, and NO levels. The results showed that right hemispheric dominant individuals had increased plasma HMG CoA reductase activity and elevated digoxin levels, decreased plasma magnesium and RBC membrane Na(+)-K(+) ATPase activity, and increased levels of NO. Left hemispheric dominant individuals had the opposite patterns with reduced nitric oxide synthesis. Cerebral chemical dominance can regulate nitric oxide synthesis.

Hypothalamic digoxin, hemispheric dominance, and family bonding behavior

The isoprenoid pathway produces endogenous digoxin, a substance that can regulate neurotransmitter and amino acid transport. Digoxin synthesis and neurotransmitter patterns were assessed in individuals with differing family bonding patterns. The family bonding patterns were assessed by the FACES scale--family adaptability and cohesiveness evaluation scale. The criteria given in the handbook for the 16 PF--16 personality factors questionnaire by Cattell, Eber, and Tatsouke--was also chosen for assessing the individual personality aspect of family bonding after suitable modification. The patterns were compared in those with right hemispheric and left hemispheric dominance. Digoxin synthesis was increased with upregulated tryptophan catabolism (increased levels of serotonin, strychnine, and nicotine) and downregulated tyrosine catabolism (decreased levels of dopamine, noradrenaline, and morphine) in those with reduced family bonding and right hemispheric dominance. Digoxin synthesis was reduced with downregulated tryptophan catabolism (decreased levels of serotonin, strychnine, and nicotine) and upregulated tyrosine catabolism (increased levels of dopamine, noradrenaline, and morphine) in those with increased family bonding and left hemispheric chemical dominance. Hypothalamic digoxin plays a central role in the regulation of family bonding behavior. Hemispheric chemical dominance in relation to digoxin status is also crucial in this respect.

Hypothalamic-mediated model for Creutzfeldt-Jakob disease: relation to hemispheric chemical dominance

The isoprenoid pathway including endogenous digoxin was assessed in Creutzfeldt-Jakob Disease (CJD). This was also studied for comparison in patients with right hemispheric and left hemispheric dominance. The isoprenoid pathway was upregulated with increased digoxin synthesis in patients with CJD and in those with right hemispheric chemical dominance. In this group of patients (i) the tryptophan catabolites were increased and the tyrosine catabolites reduced, (ii) the dolichol and glycoconjugate levels were elevated, (iii) lysosomal stability was reduced, (iv) ubiquinone levels were low and free radical levels increased, and (v) the membrane cholesterol:phospholipid ratios were increased and membrane glyco conjugates reduced. On the other hand, in patients with left hemispheric chemical dominance, the reverse patterns were obtained. The role of the isoprenoid pathway in the pathogenesis of CJD and its relation to hemispheric chemical dominance is discussed.

Hypothalamic digoxin, cerebral chemical dominance, and calcium/magnesium metabolism

The study assessed the biochemical differences between right hemispheric dominant and left hemispheric dominant individuals. The HMG CoA reductase activity, isoprenoid metabolites--serum digoxin--serum magnesium, and RBC membrane Na+-K+ ATPase activity were also studied. The results showed that right hemispheric chemically dominant individuals had increased (i) HMG CoA reductase activity, elevated digoxin levels, (ii) reduced RBC membrane Na+-K+ ATPase activity and serum magnesium levels. Left hemispheric chemically dominant individuals had the opposite patterns. Right hemispheric chemical dominance represents a hyperdigoxinemic/hypomagnesemic state with membrane sodium-potassium ATPase inhibition. Left hemispheric chemical dominance represents the reverse pattern with hypodigoxinemia/hypermagnesemia and membrane sodium-potassium ATPase stimulation. Cerebral chemical dominance can regulate calcium/magnesium metabolism.

The concept of cerebral chemical dominance

The study assessed the biochemical differences between right hemispheric dominant and left hemispheric dominant individuals detected by handedness and the dichotic listening test. The isoprenoid metabolites--digoxin, dolichol, and ubiquinone, glycoconjugate metabolism, free radical metabolism, and the RBC membrane composition were studied in individuals with differing hemispheric dominance. The results showed that all right hemispheric dominant individuals and 50% of left hemispheric dominant individuals had increased HMG CoA reductase activity, elevated digoxin and dolichol levels. The serum magnesium, RBC membrane Na+-K+ ATPase activity and serum ubiquinone levels were reduced in all right hemispheric dominant individuals and 50% of left hemispheric dominant individuals. The tryptophan-derived neurotransmitters--serotonin, quinolinic acid, strychnine, and nicotine--were increased while the tyrosine derived neurotransmitters--dopamine, noradrenaline, and morphine--were reduced in all right hemispheric dominant individuals and 50% of left hemispheric dominant individuals. The other 50% of left hemispheric dominant individuals had decreased HMG CoA reductase activity, reduced digoxin, and dolichol levels. The serum magnesium, RBC membrane Na+-K+ ATPase activity, and serum ubiquinone levels were increased in this group. The tryptophan derived neurotransmitters--serotonin, quinolinic acid, strychnine, and nicotine were reduced, while the tyrosine-derived neurotransmitters--dopamine, noradrenaline, and morphine-- were increased in the rest (50% of left hemispheric dominant individuals). Hemispheric dominance detected by the dichotic listening test and handedness has no correlation with cerebral chemical dominance.

Hypothalamic digoxin, regulation of neuronal transmission, and cerebral dominance

The present study assessed the neurochemical differences between right hemispheric dominant and left hemispheric dominant individuals. The HMG CoA reductase activity, serum digoxin, magnesium, tryptophan catabolites, tyrosine catabolites, and RBC membrane (Na+)-K+ ATPase activity were measured in individuals of differing hemispheric dominance. The results showed that right hemispheric dominant individuals had elevated digoxin synthesis, increased tryptophan catabolites, and reduced tyrosine catabolites and membrane (Na+)-K+ ATPase with hypomagnesemia. Left hemispheric dominant individuals had the opposite patterns. Right hemispheric dominance represents a hyperdigoxinemic state with membrane sodium-potassium ATPase inhibition. Left hemispheric dominance represents the reverse pattern with hypodigoxinemia and membrane sodium-potassium ATPase stimulation.

Hypothalamic digoxin and hemispheric chemical dominance: relation to speech and language dysfunction

The isoprenoid pathway produces three key metabolites--endogenous digoxin, dolichol, and ubiquinone. Since endogenous digoxin can regulate neurotransmitter transport and dolichols can modulate glycoconjugate synthesis important in synaptic connectivity, the pathway was assessed in patients with dyslexia, delayed recovery from global aphasia consequent to a dominant hemispheric thrombotic infarct, and developmental delay of speech milestone. The pathway was also studied in right hemispheric, left hemispheric, and bihemispheric dominance to find out the role of hemispheric dominance in the pathogenesis of speech disorders. The plasma/serum--activity of HMG CoA reductase, magnesium, digoxin, dolichol, ubiquinone--and tryptophan/tyrosine catabolic patterns, as well as RBC (Na+)-K+ ATPase activity, were measured in the above mentioned groups. The glycoconjugate metabolism and membrane composition was also studied. The study showed that in dyslexia, developmental delay of speech milestone, and delayed recovery from global aphasia there was an upregulated isoprenoidal pathway with increased digoxin and dolichol levels. The membrane (Na+)-K+ ATPase activity, serum magnesium and ubiquinone levels were low. The tryptophan catabolites were increased and the tyrosine catabolites including dopamine decreased in the serum contributing to a speech dysfunction. There was an increase in carbohydrate residues of glycoproteins, glycosaminoglycans, and glycolipids levels as well as an increased activity of GAG degrading enzymes and glyco hydrolases in the serum. The cholesterol:phospholipid ratio of RBC membrane increased and membrane glycoconjugates showed a decrease. All of these could contribute to altered synaptic inactivity in these disorders. The patterns correlated with those obtained in right hemispheric chemical dominance. Right hemispheric chemical dominance may play a role in the genesis of these disorders. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test.

Hypothalamic digoxin and isoprenoid pathway dysfunction relation to alcoholic addiction, alcoholic cirrhosis, and acquired hepatocerebral degeneration--relation to hemispheric chemical dominance

The isoprenoid pathway produces three key metabolites--endogenous digoxin (modulate tryptophan/tyrosine transport), dolichol (important in N-glycosylation of proteins), and ubiquinone (free radical scavenger). It was considered pertinent to assess the pathway in alcoholic addiction, alcoholic cirrhosis, and acquired hepatocerebral degeneration. Since endogenous digoxin can regulate neurotransmitter transport, the pathway and the related cascade were also assessed in individuals with differing hemispheric dominance to find out the role of hemispheric dominance in its pathogenesis. In the patient group there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels, and low ubiquinone and elevated free radical levels. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites, as well as reduced endogenous morphine synthesis from tyrosine. There was an increase in cholesterol:phospholipid ratio and a reduction in glycoconjugate level of RBC membrane in these groups of patients. Alcoholic cirrhosis, alcoholic addiction, and acquired hepatocerebral degeneration are associated with an upregulated isoprenoid pathway and elevated digoxin secretion from the hypothalamus. This can contribute to NMDA excitotoxicity and altered connective tissue/lipid metabolism important in its pathogenesis. Endogenous morphine deficiency plays a role in alcoholic addiction. The same biochemical patterns were obtained in those with right hemispheric chemical dominance. Alcoholic addiction, alcoholic cirrhosis, and acquired hepatocerebral degeneration occur in right hemispheric, chemically dominant individuals.

Hypothalamic digoxin, hemispheric chemical dominance, and creativity

The human hypothalamus produces an endogenous membrane Na(+)-K+ ATPase inhibitor, digoxin, which regulates neuronal transmission. The digoxin status and neurotransmitter patterns were studied in creative and non-creative individuals, as well as in individuals with differing hemispheric dominance, in order to find out the role of cerebral dominance in this respect. The activity of HMG CoA reductase and serum levels of digoxin, magnesium, tryptophan catabolites, and tyrosine catabolites were measured in creative/non-creative individuals, and in individuals with differing hemispheric dominance. In creative individuals there was increased digoxin synthesis, decreased membrane Na(+)-K+ ATPase activity, increased tryptophan catabolites (serotonin, quinolinic acid, and nicotine), and decreased tyrosine catabolites (dopamine, noradrenaline, and morphine). The pattern in creative individuals correlated with right hemispheric dominance. In non-creative individuals there was decreased digoxin synthesis, increased membrane Na(+)-K+ ATPase activity, decreased tryptophan catabolites (serotonin, quinolinic acid, and nicotine), and increased tyrosine catabolites (dopamine, noradrenaline, and morphine). This pattern in non-creative individuals correlated with that obtained in left hemispheric chemical dominance. Hemispheric chemical dominance and hypothalamic digoxin could regulate the predisposition to creative tendency.

Hypothalamic digoxin, hemispheric chemical dominance, and sleep

The isoprenoid path way produces endogenous digoxin, a substance that can regulate neurotransmitter and amino acid transport. Digoxin synthesis and neurotransmitter patterns were assessed in individuals with chronic insomnia. The patterns were compared in those with right hemispheric and left hemispheric dominance. The activity of HMG GoA reductase and serum levels of digoxin, magnesium, tryptophan catabolites, and tyrosine catabolites were measured in individuals with chronic insomnia and in individuals with differing hemispheric dominance. Digoxin synthesis was increased with upregulated tryptophan catabolism (increased levels of serotonin, strychnine, and nicotine), and downregulated tyrosine catabolism (decreased levels of dopamine, noradrenaline, and morphine) in those with chronic insomnia and right hemispheric chemical dominance. Digoxin synthesis was reduced with downregulated tryptophan catabolism (decreased levels of serotonin, strychnine, and nicotine) and upregulated tyrosine catabolism (increased levels of dopamine, noradrenaline, and morphine) in those with normal sleep patterns and left hemispheric chemical dominance. Hypothalamic digoxin plays a central role in the regulation of sleep behavior. Hemispheric chemical dominance in relation to digoxin status is also crucial.

Hypothalamic digoxin-mediated model for Parkinson's disease

The isoprenoid pathway produces four key metabolites important in cellular function--digoxin (endogenous membrane Na(+)-K+ ATPase inhibitor), dolichol (important in N-glycosylation of proteins), ubiquinone (free-radical scavenger), and cholesterol (component of cellular membranes). This study assessed the changes in the isoprenoid pathway and the consequences of its dysfunction in Parkinson's disease (PD). There was an elevation in plasma HMG CoA reductase activity, serum digoxin and dolichol levels, and a reduction in serum magnesium, RBC membrane Na(+)-K+ ATPase activity, and serum ubiquinone levels. Serum tryptophan, serotonin, strychnine, nicotine, and quinolinic acid were elevated, while tyrosine, morphine, dopamine, and noradrenaline were decreased. The total serum glycosaminoglycans (GAG) and glycosaminoglycan fractions (except chondroitin sulphates and hyaluronic acid), the activity of GAG degrading enzymes, carbohydrate residues of serum glycoproteins, the activity of glycohydrolase-beta galactosidase, and serum glycolipids were elevated. HDL cholesterol was reduced and free fatty acids increased. The RBC membrane glycosaminoglycans, hexose and fucose residues of glycoproteins and cholesterol were reduced, while phospholipid was increased. The activity of all serum free-radical scavenging enzymes, concentration of glutathione, alpha tocopherol, iron binding capacity, and ceruloplasmin decreased significantly in PD, while the concentration of serum lipid peroxidation products and nitric oxide increased. A dysfunctional isoprenoid pathway and related cascade are important in the pathogenesis of Parkinson's disease. A hypothalamic digoxin mediated model for Parkinson's disease is also postulated.

Hypothalamic digoxin and hemispheric chemical dominance--relation to the pathogenesis of senile osteoporosis, degenerative osteoarthritis, and spondylosis

The isoprenoid pathway produces three key metabolites: i) digoxin (a membrane sodium-potassium ATPase inhibitor which can regulate intracellular calcium/magnesium ratios), ii) dolichol (which regulates N-glycosylation of proteins), and iii) ubiquinone (a free radical scavenger), all of which are important in bone and joint metabolism. The pathway was assessed in senile osteoporosis, spondylosis, and osteoarthritis. Digoxin could possibly play a role in the genesis of cerebral dominance because it can regulate multiple neurotransmitter systems. The pathway was also assessed in individuals of differing hemispheric dominance for comparison and to find out the role of cerebral dominance in the pathogenesis of these diseases. The plasma/serum-activity of HMG CoA reductase, magnesium, digoxin, dolichol, ubiquinone, and tryptophan/tyrosine catabolic patterns, as well as RBC Na(+)-K+ ATPase activity, were measured in the above mentioned groups. The glycoconjugate metabolism, free radical metabolism, and membrane composition were also studied. The pathway was upregulated with increased digoxin synthesis in patients with spondylosis and osteoarthritis. In this group of patients, the glycoconjugate levels and dolichol levels were increased and lysosomal stability reduced. The ubiquinone levels were low and free radicals increased in spondylosis and osteoarthritis. On the other hand, in senile osteoporosis, the isoprenoid pathway was downregulated and digoxin synthesis reduced. The glycoconjugate and dolichol levels were low and lysosomal stability increased. The ubiquinone levels were increased and free radical production increased in senile osteoporosis. The significance of these changes in the pathogenesis of osteoarthritis, spondylosis, and osteoporosis is discussed. The hyperdigoxinemic state is seen in osteoarthritis and spondylosis and in right hemispheric dominance. The hypodigoxinemic state is seen in left hemispheric dominance and senile osteoporosis. Hemispheric dominance plays a crucial role in deciding the predisposition to bone and joint diseases. Right hemispheric chemical dominance predisposes to spondylosis and osteoarthritis. Left hemispheric chemical dominance predisposes to osteoporosis.

Hypothalamic digoxin, hemispheric chemical dominance, and Alzheimer's disease

This study assessed the changes in the isoprenoid pathway and the consequences of its dysfunction in Alzheimer's disease (AD). The isoprenoid pathway and digoxin status were also studied for comparison in individuals of differing hemispheric dominance to find the role of cerebral dominance in the genesis of Alzheimer's disease. There was elevation in plasma HMG CoA reductase activity, serum digoxin, and dolichol levels, and a reduction in serum magnesium, RBC membrane Na(+)-K+ ATPase activity, and serum ubiquinone levels. Serum tryptophan, serotonin, strychnine, nicotine, and quinolinic acid were elevated, while serum tyrosine, morphine, dopamine, and noradrenaline were decreased. The total serum glycosaminoglycans and glycosaminoglycan fractions, the activity of GAG degrading enzymes and glycohydrolases, carbohydrate residues of glycoproteins, and serum glycolipids were elevated in Alzheimer's disease. HDL cholesterol was reduced and free fatty acids increased. The RBC membrane glycosaminoglycans, hexose, and fucose residues of glycoproteins and cholesterol were reduced, while phospholipid increased. The activity of all free radical scavenging enzymes, concentration of glutathione, alpha tocopherol, iron binding capacity, and ceruloplasmin decreased significantly in Alzheimer's disease, while the concentration of lipid peroxidation products and NO increased. The hypomagnesemia-related NMDA excitotoxicity, ubiquinone deficiency related mitochondrial dysfunction, and altered glycoconjugates/lysosomal stability could contribute to the pathogenesis of Alzheimer's disease. The biochemical patterns, including hyperdigoxinemia observed in Alzheimer's disease, correlated with those obtained in right hemispheric chemical dominance. Right hemispheric chemical dominance is a predisposing factor for Alzheimer's disease.

Lipid-lowering efficacy of hesperetin metabolites in high-cholesterol fed rats

BACKGROUND

Hesperetin is a naturally occurring flavonoid that has hypolipidemic properties.

METHODS

Male rats were fed a 1 g/100 g high-cholesterol diet for 5 weeks along with hesperetin (0.02%, 0.066 mmol/100 g diet) and hesperetin metabolites. The hesperetin metabolites, m-hydroxycinnamic acid (m-HC), 3,4-dihydroxyphenylpropionic acid (3,4-DHPP), and 3-methoxy-4-hydroxycinnamic acid (ferulic acid), were supplemented based on an equivalent amount of hesperetin.

RESULTS

The supplementation of hesperetin and its metabolites significantly lowered the plasma total cholesterol and triglyceride concentrations compared to the control group. The hepatic HMG-CoA reductase and acyl-CoA:cholesterol acyltransferase (ACAT) activities were significantly lower in the hesperetin and its metabolite supplemented groups than in the control group. The excretion of acidic sterol was significantly higher in the hesperetin, m-HC, 3,4-DHPP, and ferulic acid supplemented groups than in the control group.

CONCLUSIONS

These results demonstrated that the hesperetin metabolites played as potent a role as hesperetin in plasma lipid-lowering activities in vivo, and further suggest that cholesterol biosynthesis and esterification were concomitantly reduced by hesperetin and its metabolites, as indicated by the decreased HMG-CoA reductase and ACAT activities.

Sex and hormonal status modulate the effects of psyllium on plasma lipids and monocyte gene expression in humans

Psyllium (PSY) intake decreases plasma LDL cholesterol (LDL-C) in men and pre- and post-menopausal women while PSY effects on plasma triglycerides (TG) are sex related. A significant decrease in plasma TG was observed in men while postmenopausal women experienced an increase in plasma TG concentrations following PSY supplementation. To further explore the mechanisms by which sex and hormonal status influence the effects of PSY on plasma lipids, HMG-CoA reductase, LDL receptor and lipoprotein lipase (LPL) mRNA abundance were measured in mononuclear cells isolated from these subjects. The intervention followed a randomized crossover design in which participants were allocated to either 15 or 0 g (control) of PSY/d for 30 d. Compared to the control period, PSY intake induced a 20% increase in HMG-CoA reductase mRNA abundance (P < 0.05) while no significant changes in LDL receptor mRNA abundance were observed. In contrast, LPL mRNA abundance was 24% higher in men and 23% lower in postmenopausal women (P < 0.05) when comparing PSY with the control period. These results suggest that the LDL-C lowering induced by PSY was related to changes in HMG-CoA reductase gene expression in monocytes while the expression of LPL in this system was affected by sex and hormonal status.

Isoprenoid pathway related cascade in multiple myeloma

This study assessed the changes in the isoprenoid pathway and its metabolites digoxin, dolichol and ubiquinone in multiple myeloma. The following parameters were assessed: isoprenoid pathway metabolites, tyrosine and tryptophan catabolites, glycoconjugate metabolism, RBC membrane composition and free radical metabolism. There was elevation in plasma HMG CoA reductase activity, serum digoxin and dolichol and a reduction in RBC membrane Na+ - K+ ATPase activity, and serum ubiquinone levels. Serum tryptophan, serotonin, nicotine, strychnine and quinolinic acid were elevated while tyrosine, dopamine, noradrenaline and morphine were decreased. The total serum glycosaminoglycans and glycosaminoglycan fractions, the activity of GAG degrading enzymes and glycohydrolases, carbohydrate residues of glycoproteins and serum glycolipids were elevated. The RBC membrane glycosaminoglycans, hexose and fucose residues of glycoproteins, cholesterol and phospholipids were reduced. The activity of all free radical scavenging enzymes, concentration of glutathione, iron binding capacity and ceruloplasmin decreased significantly while the concentration of lipid peroxidation products and NO increased. Hyperdigoxinemia related altered intracellular Ca++ mediated oncogene activation, dolichol induced altered glycoconjugate metabolism and ubiquinone deficiency related mitochondrial dysfunction can contribute to the pathogenesis of multiple myeloma. The biochemical findings reported could be the cause or the consequence of multiple myeloma.

Hypothalamic digoxin-mediated model for subacute sclerosing panencephalitis

The isoprenoid pathway including endogenous digoxin was assessed in subacute sclerosing panencephalitis (SSPE). This was also studied for comparison in patients with right hemispheric and left hemispheric dominance. The following parameters were measured in patients with SSPE and in individuals with right hemispheric, left hemispheric and bihemispheric dominance-(a) plasma HMG CoA reductase, digoxin, dolichol, ubiquinone, and magnesium levels; (b) tryptophan/tyrosine catabolic patterns; (c) free-radical metabolism; (d) glycoconjugate metabolism; and (e) membrane composition and RBC membrane Na(+)-K(+) ATPase activity. The isoprenoid pathway was upregulated with increased digoxin synthesis in patients with SSPE and in those with right hemispheric dominance. In this group of patients: (a) the tryptophan catabolites were increased and the tyrosine catabolites reduced; (b) the dolichol and glycoconjugate levels were elevated; (c) lysosomal stability was reduced; (d) ubiquinone levels were low and free-radical levels increased; and (e) the membrane cholesterol:phospholipid ratios were increased and membrane glycoconjugates reduced. On the other hand, in patients with left hemispheric dominance the reverse patterns were obtained. The upregulated isoprenoid pathway and hypothalamic digoxin are involved in the pathogenesis of SSPE. SSPE occurs in right hemispheric chemically dominant individuals and a pathogenetic model for SSPE implicating hypothalamic digoxin is proposed.

Hypothalamic digoxin deficiency in obsessive compulsive disorder and la Tourette's syndrome

The isoprenoid pathway related cascade was assessed in 15 patients with obsessive compulsive disorder (OCD) and la Tourette's syndrome (TS). The pathway was also assessed in right hemispheric dominant, left hemispheric dominant, and bihemispheric dominant individuals to assess whether hemispheric dominance has any correlation with these disease states. The levels of serum digoxin, HMG CoA reductase activity, and dolichol were found to be decreased in OCD and la Tourette's syndrome as well as in left hemispheric dominant individuals with a corresponding increase in RBC Na(+)-K+ ATPase activity, serum ubiquinone, and magnesium levels. There was an increase in tyrosine and its catabolites, and a reduction in tryptophan and its catabolites in the serum. The total and individual glycosaminoglycan (GAG) fractions, carbohydrate residues of glycoproteins, and the concentration of glycolipids decreased in the serum. The activity of GAG degrading enzymes and glycohydrolases were decreased. The RBC membrane glycoconjugates were increased while the membrane cholesterol:phospholipid ratio was decreased. The activity of free radical scavenging enzymes increased while the concentration of free radicals decreased significantly. On the other hand, there was hyperdigoxinemia and the reverse biochemical patterns in those with right hemispheric dominance. Membrane Na(+)-K+ ATPase stimulation can result in decreased intracellular Ca2+ and increased magnesium levels. Increased levels of dopamine can lead to a tic syndrome, while reduced levels of serotonin and increased dopamine can both lead to obsessive compulsive disorder. Decrease in fucose and sialo-ligands, increased immunosuppressive morphine levels, decreased T-cell calcineurin signal transduction related to decreased intracellular calcium, reduced free radical production, and altered presentation of bacterial glycoconjugate antigens can lead to a hypoimmune response and recurrent respiratory infection in OCD patients. OCD and la Tourette's syndrome are associated with left hemispheric chemical dominance.

Hypothalamic digoxin, hemispheric dominance, and neuroimmune integration

The isoprenoid pathway produces three key metabolites--digoxin (membrane Na(+)-K+ ATPase inhibitor, regulator of neurotransmitter transport, and immunomodulatory agent), dolichol (regulatory of N-glycosylation of proteins), and ubiquinone (free-radical scavenger). The pathway was assessed in systemic lupus erythematosis with neuropsychiatric manifestations, slow viral diseases (subacute sclerosing panencephalitis [SSPE], and Creutzfeldt-Jakob disease [CJD]) and patients with recurrent respiratory infections. This was also studied for comparison in patients with right hemispheric and left hemispheric dominance. The isoprenoid pathway was upregulated with increased digoxin synthesis in patients with neurolupus, SSPE, and CJD, and in those with right hemispheric dominance. The tryptophan catabolites were increased and the tyrosine catabolites reduced. In these patients the dolichol and glycoconjugate levels were elevated and lysosomal stability was reduced. The ubiquinone levels were low and free-radical levels increased in these patients. The membrane cholesterol:phospholipid ratios were increased and membrane glycoconjugates reduced. On the other hand, in patients with recurrent respiratory infection and left hemispheric dominance, the reverse patterns and hypodigoxinemia with a downregulated isoprenoid pathway were noticed. The isoprenoid pathway is important in the pathogenesis of neurolupus, CJD, SSPE, and recurrent respiratory infections. Hypothalamic digoxin and chemical hemispheric dominance play an important role in the regulation of immunity.

A hypothalamic digoxin mediated model for conscious and subliminal perception

The isoprenoid pathway and its metabolites--digoxin, dolichol and ubiquinone were assessed in schizophrenia. There was an upregulation of the isoprenoid pathway as evidenced by elevated HMG CoA reductase activity. Digoxin, an endogenous Na+-K+ ATPase inhibitor secreted by the hypothalamus was found to be elevated and RBC membrane Na+-K+ ATPase activity was found to be reduced in schizophrenia. Membrane Na+-K+ ATPase inhibition can result in increased intracellular Ca2+ and reduced magnesium levels. Hypothalamic digoxin can modulate conscious and subliminal perception and its dysfunction may lead on to schizophrenia. Digoxin can also preferentially upregulate tryptophan transport over tyrosine resulting in increased levels of depolarising tryptophan catabolites--serotonin and quinolinic acid (NMDA agonist), and decreased levels of hyperpolarising tyrosine catabolites--dopamine and noradrenaline contributing to membrane Na+-K+ ATPase inhibition. NMDA excitotoxicity could result from hypomagnesemia induced by membrane Na+-K+ ATPase inhibition and quinolinic acid, an NMDA agonist acting on the NMDA receptor. Hypomagnesemia and increased dolichol level can affect glycoconjugate metabolism and membranogenesis leading on to disordered synaptic connectivity in the limbic allocortex and defective presentation of viral antigens and neuronal antigens contributing to autoimmunity and viral persistance important in the pathogenesis. Membrane Na+-K+ ATPase inhibition can produce immune activation, a component of autoimmunity. Mitochondrial dysfunction consequent to altered calcium/magnesium ratios and reduced ubiquinone levels can result in increased free radical generation and reduced free radical scavenging & defective apoptosis leading on to abnormal synaptogenesis. Schizophrenia can thus be considered as a syndrome of hypothalamic digoxin hypersecretion consequent to an upregulated isoprenoid pathway.

Hypothalamic digoxin mediated model for oncogenesis

This study assessed the changes in the isoprenoid pathway and its metabolites digoxin, dolichol and ubiquinone in neoplasms (CNS astrocytomas - glioblastoma multiforme and high grade non - Hodgkin's lymphoma). The following parameters were assessed-isoprenoid pathway metabolites, tyrosine and tryptophan catabolites, glycoconjugate metabolism, RBC membrane composition and free radical metabolism. There was an elevation in plasma HMG CoA reductase activity, serum digoxin and dolichol and a reduction in RBC membrane Na+-K+ ATPase activity, serum ubiquinone and magnesium levels. Serum tryptophan, serotonin, nicotine and quinolinic acid were elevated while tyrosine, dopamine, noradrenaline and morphine were decreased. The total serum glycosaminoglycans and glycosaminoglycan fractions (except dermatan sulphate in the case of CNS astrocytomas), the activity of GAG degrading enzymes and glycohydrolases, carbohydrate residues of glycoproteins and serum glycolipids were elevated. HDL cholesterol showed a significant decrease and free fatty acids & triglycerides were increased. The RBC membrane glycosaminoglycans, hexose and fucose residues of glycoproteins and phospholipids were reduced. The activity of all free radical scavenging enzymes, concentration of glutathione, iron binding capacity and ceruloplasmin decreased significantly while the concentration of malondialdehyde (MDA), hydroperoxides, conjugated dienes and NO increased. The concentration of alpha tocopherol was unaltered. Membrane Na+-K+ ATPase inhibition due to elevated digoxin, altered membrane structure and digoxin related tyrosine / tryptophan transport defect leading to increased levels of depolarising tryptophan catabolites and decreased levels of hyperpolarising tyrosine catabolites can lead to alteration in intracellular calcium/magnesium ratios and oncogene activation. Intracellular magnesium deficiency can produce defective microtubule related spindle fibre dysfunction and chromosomal non-dysjunction contributing to neoplastic cellular polyploidy and aneuploidy. Digoxin induced tryptophan/tyrosine transport defect can alter neurotransmitter patterns with increased serotonin, quinolinic acid, nicotine & glutamatergic transmission and reduced dopamine, morphine and noradrenaline levels leading to oncogenesis. Glycoconjugate metabolism is altered by elevated dolichol levels and magnesium depletion consequent to Na+-K+ ATPase inhibition. There is a qualitative alteration in proteoglycans and glycoproteins, defective membrane formation and structure and reduced lysosomal stability leading to disordered contact inhibition and tumour antigen presentation contributing to oncogenesis. Digoxin induced alteration in intracellular calcium/magnesium ratios and low ubiquinone levels can lead to a mitochondrial dysfunction resulting in increased free radical generation and reduced scavenging & caspase-3 activation producing a P21 defect contributing to oncogenesis.

Membrane Na+ K+ ATPase inhibition related dyslipidemia and insulin resistance in neuropsychiatric disorders

There are several reports in literature implicating cholesterol metabolism in the pathogenesis of neuronal degenerations, oncogenesis, functional neuropsychiatric disorders and multiple sclerosis. Biosynthesis of cholesterol takes place by the isoprenoid pathway, which also produces digoxin, an inhibitor of membrane Na(+)-K+ ATPase. Inhibition of this enzyme results in intracellular Mg++ deficiency which can influence cholesterol metabolism. Digoxin also influences transport of tryptophan and tyrosine which are precursors of various neurotransmitters. Alterations in digoxin, membrane Na(+)-K+ ATPase and also in neurotransmitters have been reported in the disorders mentioned above. In view of this, serum lipid profile, activity of plasma HMG CoA reductase (the major rate limiting step in the isoprenoid pathway), RBC membrane Na(+)-K+ ATPase activity, serum Mg++ concentration, concentration of digoxin and concentration of serum neurotransmitters were studied in some neuropsychiatric disorders. The serum serotonin level was increased while that of serum dopamine and noradrenaline was reduced. Serum digoxin levels were high and RBC membrane sodium-potasium ATPase activity and serum magnesium were reduced. There was a reduction in HDL cholesterol and increase in plasma triglycerides (pattern similar to insulin resistance and syndrome X) in most of the disorders studied. The HMG CoA reductase activity was high, the serum total cholesterol was increased while RBC membrane cholesterol was reduced in most of the cases. The significance of increased digoxin with consequent inhibition of membrane Na(+)-K+ ATPase in relation to changes in cholesterol metabolism and insulin resistance type of dyslipidemia is discussed in this paper.

Simvastatin preserves coronary endothelial function in hypercholesterolemia in the absence of lipid lowering

Recent evidence suggests that some benefit from the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors may occur independent of lipid lowering. We aimed to determine the effect of simvastatin on coronary endothelial function, endothelial NO synthase (eNOS) expression, and oxidative stress in experimental hypercholesterolemia (HC) in the absence of cholesterol lowering. Pigs were randomized to 3 experimental groups: normal diet (N group), high cholesterol diet (HC group), and HC diet with simvastatin (HC+S group) for 12 weeks. Low density lipoprotein cholesterol was similarly increased in the HC and HC+S groups compared with the N group. In vitro analysis of coronary large- and small-vessel endothelium-dependent vasorelaxation was performed. The mean vasorelaxation of epicardial vessels to bradykinin was significantly attenuated in the HC group compared with the N group (32.3+/-1.2% versus 42.9+/-1.6%, respectively; P<0.0001). This attenuation was significantly reversed in the HC+S group (38.7+/-1.5%, P<0.005 versus HC group). The maximal vasorelaxation to substance P was significantly attenuated in the HC group compared with the N group (50.5+/-11.9% versus 79.3+/-5.3%, respectively; P<0.05). This attenuated response was normalized in the HC+S group (74.9+/-4.1%, P<0.05 versus HC group). The maximal arteriolar vasorelaxation to bradykinin was also significantly attenuated in the HC group compared with the N group (71.9+/-4.9% versus 96.8+/-1.34%, respectively; P<0.005). This was reversed in the HC+S group (98.4+/-0.6%, P<0.0001 versus HC group). Western blotting of coronary tissue homogenates for eNOS demonstrated a decrease in protein levels in the HC group compared with the N group, with normalization in the HC+S group. Elevation of plasma F(2)-isoprostanes and thiobarbituric acid-reactive substances, markers of oxidative stress, occurred in the HC compared with the N group. These changes were reversed in the HC+S group. In summary, simvastatin preserves endothelial function in coronary epicardial vessels and arterioles in experimental HC (in the absence of cholesterol lowering) in association with an increase in coronary eNOS levels and a decrease in oxidative stress. These alterations may play a role in the reduction in cardiac events after treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors.

Hypothalamic digoxin, hemispheric dominance and the acquired immunodeficiency syndrome

OBJECTIVES

Hypothalamic digoxin, an isoprenoidal metabolite, is an endogenous regulator of membrane Na(+)-K(+) ATPase activity, immune activation and synaptic neurotransmission. The objective of this study was to assess the role of hypothalamic digoxin and hemispheric dominance in the pathogenesis of the acquired immunodeficiency syndrome (AIDS) and in the genesis of sexual orientation.

METHODS

The isoprenoid-pathway-related cascade - (i) isoprenoidal metabolites - digoxin, dolichol and ubiquinone, (ii) tryptophan/tyrosine catabolic patterns, (iii) glycoconjugate metabolism, (iv) free radical metabolism and (v) membrane composition were assessed in AIDS (CDC stage - group IV - subgroup C), individuals with differing hemispheric dominance as well as in individuals with differing sexual orientation. Statistical analysis was done by Student's t test with modified degrees of freedom.

RESULTS

The HMG CoA reductase activity was increased with increased digoxin and dolichol levels and reduced ubiquinone levels in AIDS. The membrane Na(+)-K(+) ATPase activity and serum magnesium levels were reduced. The tryptophan catabolites (serotonin, quinolinic acid, nicotine and strychnine) were increased and the tyrosine catabolites (morphine, dopamine and noradrenaline) were reduced. The serum glycoconjugate metabolites were increased and lysosomal stability was reduced in AIDS. There was reduced incorporation of glycoconjugates into membranes and an increased membrane cholesterol:phospholipid ratio. Lipid peroxidation products and NO were increased while free radical scavenging enzymes and reduced glutathione were reduced. The biochemical patterns obtained in AIDS correlated with those obtained in right-hemispheric dominance and homosexuals/bisexual states.

CONCLUSIONS

Hypothalamic digoxin and right-hemispheric dominance is important in the predisposition to AIDS as well as homosexual/bisexual states.

Tryptophan and tyrosine catabolic pattern in neuropsychiatric disorders

Catabolism of tryptophan and tyrosine in relation to the isoprenoid pathway was studied in neurological and psychiatric disorders. The concentration of trytophan, quinolinic acid, kynurenic acid, serotonin and 5-hydroxyindoleacetic acid was found to be higher in the plasma of patients with all these disorders; while that of tyrosine, dopamine, epinephrine and norepinephrine was lower. There was increase in free fatty acids and decrease in albumin (factors modulating tryptophan transport) in the plasma of these patients. Concentration of digoxin, a modulator of amino acid transport, and the activity of HMG CoA reductase, which synthesizes digoxin, were higher in these patients; while RBC membrane Na+-K+ ATPase activity showed a decrease. Concentration of plasma ubiquinone (part of which is synthesised from tyrosine) and magnesium was also lower in these patients. No morphine could be detected in the plasma of these patients except in MS. On the other hand, strychnine and nicotine were detectable. These results indicate hypercatabolism of tryptophan and hypocatabolism of tyrosine in these disorders, which could be a consequence of the modulating effect of hypothalamic digoxin on amino acid transport.

Hypothalamic digoxin and neural regulation of blood pressure and vascular thrombosis

The isoprenoid pathway produces three key metabolites--digoxin (membrane sodium-potassium ATPase inhibitor and regulator of neurotransmitter/aminoacid transport), dolichol (regulates N-glycosylation of proteins) and ubiquinone (free radical scavenger). This was assessed in patients with essential hypertension, familial hypotension, acute coronary artery disease and acute thrombotic strokes. The pathway was also assessed in patients with right hemispheric, left hemispheric and bihemispheric dominance for comparison. In patients with acute coronary artery disease, acute thrombotic stroke, essential hypertension and right hemispheric dominance, there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels and low ubiquinone and high free radical levels. There was also an increase in tryptophan catabolites, reduction in tyrosine catabolites, increase in cholesterol-phospholipid ratio and a reduction in glycoconjugate level of RBC membrane in this group of patients as well as in those with right hemispheric dominance. In patients with familial hypotension and left hemispheric dominance, the patterns were reversed. The role of a dysfunctional isoprenoid pathway and endogenous digoxin in the pathogenesis of essential hypertension and familial hypotension and in thrombotic vascular disease in relation to hemispheric dominance is discussed.

Evaluation of kidney and liver subacute toxicity induced by Bezalip-Pravastatin-Lopid antihyperlipidaemic compounds in rats

Renal and hepatic subacute toxicity induced by the antihyperlipidaemic drugs: Bezalip-Pravastatin and Lopid was investigated in rats using serum biochemical parameters. Toxicological evaluation was performed in serum samples following the administration of the therapeutic dose regimens of the compounds that were previously shown to be effective in inhibition of 3-hydroxy-methylglutaryl coenzyme A (HMG CoA) reductase, the enzyme controlling the rate-limiting step in the synthesis of cholesterol, and acyl-CoA cholesterol acyl transferase (ACAT) which converts intracellular free cholesterol to cholesterol ester. Renal and hepatic subacute toxicity was evaluated by measuring enzyme activity or concentrations of: alanine aminotransferace, alkaline phosphatase, aspartate aminotransferase, gamma-glutamyltransferase, glucose, potassium, sodium, blood urea nitrogen, uric acid and creatinine. The use of the above serum biochemical parameters indicated that the overall toxicity impact of antihyperlipidaemic drugs was Bezalip = Pravastatin < Lopid. We have found that the Pravastatin--in contrast to the above antihyperlipidaemic drugs--only transiently affects the biochemical parameters associated with toxicity, but, it affects some of the biochemical parameters associated with hepatic and renal toxicity, up to a significantly lower extent than the antihyperlipidaemic drugs.

Effect of dietary cholesterol on low density lipoprotein-receptor, 3-hydroxy-3-methylglutaryl-CoA reductase, and low density lipoprotein receptor-related protein mRNA expression in healthy humans

We investigated the possibility that dietary cholesterol downregulates the expression of low density lipoprotein (LDL) receptor and 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase genes of circulating mononuclear cells in vivo in healthy humans. We also studied the variations of the LDL receptor-related protein (LRP) gene in the same conditions. Dieters (n = 5) were submitted to a 4-d fat restriction (mean cholesterol intake: 6+/-4 mg/d), followed by a 7-d cholesterol (a mean of 791+/-150 mg/d) supplementation. Controls (n = 3) did not change their diet. During fat restriction, serum total and LDL cholesterol decreased significantly (P < 0.05), and LDL receptor and HMG-CoA reductase mRNA copy numbers in mononuclear cells increased by 57 and 147%, respectively (P < 0.05). After reintroducing cholesterol, serum cholesterol was stable whereas LDL receptor and HMG-CoA reductase mRNA decreased by 46 and 72% (P < 0.05) and LRP mRNA increased by 59% (P < 0.005). The changes in LDL receptor and HMG-CoA reductase mRNA abundance were correlated (r = +0.79, P = 0.02) during cholesterol reintroduction as were LDL receptor and LRP mRNA levels, but negatively (r = -0.70, P = 0.05). Also, 70% of the variability in LRP mRNA (P < 0.005) was explained by dietary cholesterol. Thus, the basic mechanisms regulating cellular cholesterol content, the coordinate feedback repression of genes governing the synthesis and uptake of cholesterol, are operating in vivo in humans. However, serum cholesterol did not increase in response to dietary cholesterol, suggesting that these mechanisms may not play as predominant a role as previously believed in the short-term control of serum cholesterol in vivo in humans. A new finding is that LRP gene is also sensitive to dietary cholesterol, suggesting that it may participate in the control of serum cholesterol. Further in vivo studies in humans are warranted to explore the molecular mechanisms of the physiological response to dietary cholesterol in humans.

Upregulation of cholesterol synthesis after acute reduction of low density lipoprotein by apheresis in normocholesterolaemic subjects: evidence for a threshold effect

The influence of low density lipoproteins (LDL) in the plasma on the regulation of cholesterol biosynthesis is not clear. We studied the changes in plasma mevalonic acid (MVA) concentration and the lathosterol/cholesterol (L/C) ratio, which are well established indices of whole body cholesterol synthesis, in four normocholesterolaemic subjects after each had undergone LDL apheresis on two occasions. LDL apheresis of 75% of the calculated plasma volume reduced LDL-cholesterol by 44% to 1.5 +/- 0.2 mmol/l without changing plasma MVA levels or L/C ratios. Apheresis of 125% of the calculated plasma volume decreased plasma LDL-cholesterol by 69% to 0.9 +/- 0.2 mmol/l, with significant increases in plasma MVA and L/C ratio on the day after the procedure. These results imply that LDL-cholesterol is an integral part of the sterol regulatory pool and suggest that plasma levels cannot be lowered below 1-1.4 mmol/l in normal subjects without upregulating cholesterol biosynthesis.

Cholesterol and atherosclerosis

Cholesterol is an essential component of cellular membranes, but when present in excess in the circulation, can be deposited in the arterial wall, leading to the formation of atherosclerotic lesions. The principal plasma carrier of cholesterol, low density lipoprotein (LDL), is removed from the circulation by LDL receptors in the liver. This process plays a critical role in regulating plasma LDL levels. The unique structure and composition of the LDL particle makes it particularly susceptible to modification by oxidative reactions. Current evidence suggests that the production of oxidised LDL in the intima, and the removal of oxidised LDL particles by scavenger receptors on macrophages, play a central role in the development and progression of atherosclerotic lesions.

Circulating markers for biosynthesis of cholesterol and bile acids are not depressed in asymptomatic gallstone subjects

BACKGROUND/AIMS

Cholesterol gallstone disease is often associated with an increased biliary secretion rate of cholesterol, which may be due to abnormalities in hepatic cholesterol metabolism. The aim of the present study was to investigate whether gallstone subjects may have an underlying defect in hepatic cholesterol and bile acid formation.

METHODS

In 41 asymptomatic gallstone subjects, randomly selected from a population of both sexes 40 and 60 years of age, and in 72 age- and sex-matched controls, plasma levels of lathosterol (reflecting hepatic HMG CoA reductase activity) and 7alpha-hydroxy-4-cholesten-3-one (reflecting cholesterol 7alpha-hydroxylase activity) were analysed. In a subgroup of gallstone subjects and controls, plasma levels of 27-hydroxy cholesterol were also determined.

RESULTS

The gallstone subjects had normal plasma levels of cholesterol but displayed 20-25% higher plasma levels of triglycerides compared with the controls. The plasma level of lathosterol was not significantly different between the two groups of subjects whereas the plasma level of 7alpha-hydroxy-4-cholesten-3-one was about 40% higher in the gallstone subjects compared with the controls. Positive correlations were obtained between plasma levels of 7alpha-hydroxy-4-cholesten-3-one and triglycerides in both groups of subjects. The plasma level of 27-hydroxy cholesterol was similar in gallstone subjects and controls.

CONCLUSIONS

The previously reported hypersecretion of cholesterol in gallstone patients is not due to a single metabolic defect leading to increased hepatic synthesis of cholesterol or decreased catabolism of cholesterol to bile acids via 7alpha-hydroxylation or 27-hydroxylation of cholesterol.

Randomized placebo-controlled study of the effects of simvastatin on haemostatic variables, lipoproteins and free fatty acids. The Oxford Cholesterol Study Group

The Oxford Cholesterol Study is a randomized placebo-controlled trial designed primarily to assess the effects of simvastatin on blood cholesterol levels and side-effects in preparation for a large, long-term trial of the effects of cholesterol-lowering drug therapy on mortality. At present there is only limited evidence from randomized comparisons of the effects of HMG-CoA reductase inhibitors, such as simvastatin, on thrombogenic, as distinct from atherogenic, pathways in coronary heart disease. The present sub-study was carried out to assess the effects of simvastatin on a range of haemostatic variables, as well as on free fatty acids and on lipoprotein fractions not studied in detail previously. At an average of about 2 years after starting study treatment, non-fasting blood samples were obtained from a sequential sample of 162 participants who had been randomly allocated to receive 40 mg (54 patients) or 20 mg (57 patients) daily simvastatin or matching placebo treatment (51 patients). Only patients who reported taking their study treatment and who were not known to be diabetic or to be taking some other lipid lowering treatment were to be included. The principal comparisons were to be of those allocated simvastatin (i.e. 20 and 40 mg doses combined) vs those allocated placebo. Among patients allocated simvastatin, marginally significant lower factor VII antigen levels (12.10% +/- 6.08 of standard; 2P < 0.05) and non-significantly lower factor VII coagulant activity (8.24% +/- 4.99 of standard) and fibrinogen concentrations (0.10 +/- 0.08 g. l-1) were observed. In contrast, plasminogen activator inhibitor activity was significantly higher (2.62 +/- 1.03 IU; 2P < 0.01) among patients allocated simvastatin. No significant differences were seen in the other haemostatic factors studied (e.g. prothrombin fragment 1.2, factor XII and C1 inhibitor). Total free fatty acid concentration was marginally significantly reduced (2P = 0.02) with simvastatin, but none of the reductions in individual free fatty acids was significant. Lipoprotein fractions were only measured among patients allocated 40 mg daily simvastatin or placebo. Compared with placebo, simvastatin produced significant decreases not only in LDL cholesterol (1.74 +/- 0.15 mmol.1(-1): 2P < 0.0001) but also in VLDL cholesterol (0.28 +/- 0.08 mmol.1(-1); 2P < 0.001) and IDL cholesterol (0.17 +/- 0.03 mmol.1(-1); 2P < 0.0001). There were also lower triglyceride levels associated with LDL (0.07 +/- 0.01 mmol.1(-1); 2P < 0.0001), IDL (0.03 +/- 0.01 mmol.1(-1); 2P < 0.01) and VLDL (0.27 +/- 0.14; 2P = 0.05). The effects of simvastatin on haemostatic variables appear to be far less marked than its lipid effects. Given the associations of haemostatic factors with coronary heart disease incidence, larger randomized comparisons of the HMG-CoA reductase inhibitors (and of the newer fibrates which may produce greater effects) are needed to provide more reliable estimates of the extent to which they influence these variables.

A comparison of the effects of fluvastatin and bezafibrate on exercise metabolism: a placebo-controlled study in healthy normolipidaemic subjects

1. We have examined the interaction between aerobic exercise and lipid-lowering drugs in a crossover study of 16 healthy normolipidaemic volunteers who each received 21 days' treatment with bezafibrate (400 mg), fluvastatin (40 mg), and placebo, in random order. 2. Fluvastatin treatment reduced pre-exercise total cholesterol (TC) by 23% (P < 0.0001), low-density lipoprotein cholesterol (LDL-C) by 33% (P < 0.0001), and plasma triglycerides by 11%, compared with pre-treatment values. Bezafibrate reduced TC by 11% (P < 0.01); LDL-C by 9%; and plasma triglycerides by 40% (P < 0.01), compared with pre-treatment values. 3. During exercise, in comparison with placebo, and fluvastatin treatment, respectively, bezafibrate significantly reduced mean fat oxidation: 31% vs 39%, P = 0.035, 31% vs 39%, P = 0.002, plasma free fatty acid (FFA) availability, e.g. after 90 min of exercise: (t90) 520 vs 662 mumol 1(-1), P = 0.054, 520 vs 725 mumol 1(-1), P = 0.016, and plasma levels of glycerol (t90): 59 vs 74 mumol 1(-1), P = 0.037, 59 vs 73 mumol 1(-1), P = 0.016. Fluvastatin had no impact on fat metabolism in comparison with placebo. 4. Reduced plasma FFA concentration and lower fat oxidation during prolonged exercise on bezafibrate treatment may be due to an inhibition of hepatic acetyl coenzyme A carboxylase, resulting in reduced FFA release from adipose tissue. 5. The possibility that impaired fat metabolism on fibrates could induce premature fatigue during exercise of moderate duration and intensity should be examined in hyperlipidaemic patients.