Bezafibrate improves hypertension and insulin sensitivity in humans

Treatment of Ezetimibe lowers total and low-density lipoprotein cholesterol in hypercholesterolemic dogs with hyperadorenocorticism

Ezetimibe is a cholesterol absorption inhibitor that blocks the intestinal absorption of both biliary and dietary cholesterol, thereby lowering primarily low density lipoprotein-cholesterol (LDL-chol) in human studies. This study aimed to investigate the effects of ezetimibe on dyslipidemia control in nine dogs with hypercholesterolemia. Changes in total cholesterol (T-chol) and each lipoprotein fractions were evaluated at 0, 2, and 4 months following initiation of ezetimibe treatment. A significant decrease in T-chol was observed, and a mean T-chol concentration below 400 mg/dL was achieved at 2 and 4 months. Furthermore, a significant decrease in LDL-chol was observed (-53.3% and -64.3% at 2 and 4 months, respectively). Taken together, treatment of ezetimibe could lower LDL-chol levels in dogs with hypercholesterolemia.

Body mass index, neck circumference, and hypertension: a prospective cohort study

Objective

This study aimed to investigate the association between BMI combined with neck circumference and the risk of hypertension.

Methods

We selected participants from the Kailuan study in 2014 who were normotensive as our research subjects. We compared the risk of hypertension among individuals in group 1 (non-obese with low neck circumference), group 2 (non-obese with high neck circumference), group 3 (obese with low neck circumference), and group 4 (obese with high neck circumference).

Results

After a median observation period of 3.86 years, hypertension occurred in 13,383 participants. Subjects in Group 2, 3, and 4 had significantly higher risks of hypertension compared to Group 1, with hazard ratios (HRs) of 1.066 (95% CI: 1.025, 1.110), 1.322 (95% CI: 1.235, 1.415), and 1.422 (95% CI: 1.337, 1.512), respectively. Additionally, adding BMI to a conventional model had a greater incremental effect on predicting hypertension compared to adding neck circumference alone. However, considering both BMI and neck circumference together further improved the prediction of hypertension.

Conclusion

Individuals with both high BMI and high neck circumference face a higher risk of hypertension. Moreover, BMI is a superior predictor of hypertension risk compared to neck circumference, but using both of these measures can further enhance the accuracy of hypertension risk prediction.

Serum triglyceride levels and incidence of hypertension in a general Japanese population: ISSA-CKD study

The aim of this study was to clarify the relationship between fasting and nonfasting serum triglyceride (TG) levels and the incidence of hypertension in a general Japanese population. We conducted a population-based retrospective cohort study using annual health check-up data of residents of Iki City, Nagasaki Prefecture, Japan. A total of 3202 participants without hypertension at baseline were included in the present analysis. TG levels were classified as quartile 1 (<0.82 mmol/L), quartile 2 (0.83-1.13 mmol/L), quartile 3 (1.14-1.70 mmol/L) and quartile 4 (≥1.71 mmol/L) for men, and as quartile 1 (<0.70 mmol/L), quartile 2 (0.71-0.96 mmol/L), quartile 3 (0.97-1.34 mmol/L) and quartile 4 (≥1.35 mmol/L) for women. The outcome was incident hypertension. During an average follow-up of 4.4 years, 983 participants developed hypertension, according to the Cox proportional hazards model. The annual incidence of hypertension increased with an elevation in TG levels for men (5.88% in quartile 1, 8.30% in quartile 2, 7.62% in quartile 3, and 9.82% in quartile 4). This association was significant, even after adjustment for other risk factors: hazard ratio 1.41 [95% CI 1.07-1.85] for quartile 2, 1.30 [0.99-1.71] for quartile 3, and 1.59 [1.22-2.08] for quartile 4 compared with quartile 1 (p = 0.041 for trend). In contrast, there was no clear association between serum TG levels and the incidence of hypertension after adjustment for confounding factors among women (p = 0.240 for trend). High levels of serum TG were associated with the future incidence of hypertension in a general population of Japanese men but were not associated with that in women. Casual serum triglyceride levels and incidence of hypertension in a general Japanese population: ISSA-CKD study.

Dyslipidemia Increases the Risk of Incident Hypertension in a Large Taiwanese Population Follow-Up Study

Dyslipidemia is an important risk factor for hypertension and is strongly associated with an elevated risk of cardiovascular diseases including atherosclerosis and stroke. In this study, we investigated correlations between lipid profiles, including triglycerides, total cholesterol (Chol), high-and low-density lipoprotein cholesterol (HDL-C/LDL-C), and Chol/HDL-C, and baseline and incident hypertension. A total of 26,965 subjects with 4 years of follow-up data were enrolled from the Taiwan Biobank. In the cross-sectional cohort, associations between the prevalence of hypertension and lipid profiles were examined in all study participants (n = 26,965). In the longitudinal cohort, these associations were further assessed in the participants without baseline hypertension (n = 21,454). Multivariable analysis revealed that those in the second quartile (Q2) of triglycerides (compared to Q1; odds ratio (OR), 1.402; p < 0.001); Q3 of triglycerides (compared to Q1; OR, 1.365; p < 0.001); Q4 of triglycerides (compared to Q1; OR, 1.617; p < 0.001); Q3 of HDL-C (compared to Q1; OR, 0.886; p = 0.042); Q4 of HDL-C (compared to Q1; OR, 0.819; p = 0.002); Q2 of Chol/HDL-C (compared to Q1; OR, 1.144; p = 0.042); Q3 of Chol/HDL-C (compared to Q1; OR, 1.149; p = 0.034); and Q4 of Chol/HDL-C (compared to Q1; OR, 1.225; p = 0.002) were significantly associated with incident hypertension. In summary, high Chol/HDL-C, low HDL-C, and high triglycerides were associated with a higher risk of incident hypertension in the enrolled Taiwanese participants.

Relationship between casual serum triglyceride levels and the development of hypertension in Japanese

OBJECTIVE

The purpose of the present study was to investigate the effects of serum triglyceride levels on the risk of new-onset hypertension in Japanese.

METHODS

Five thousand nine hundred and thirty-three Japanese workers without hypertension at baseline, who participated in medical check-ups from 2006 to 2018, were followed retrospectively. The participants were divided into quartiles of casual serum triglyceride levels and were followed from the first to last visit of the study period. The outcome was development of hypertension. Risk estimates were computed using Cox's proportional hazards model.

RESULTS

During the follow-up period (average: 6.7 years), 946 individuals developed hypertension. The crude incidence rates of hypertension (per 1000 person-years) increased with rising serum triglyceride levels: 10.1 for quartile 1 (<0.76 mmol/l), 19.6 for quartile 2 (0.76-1.17 mmol/l), 26.0 for quartile 3 (1.18-1.84 mmol/l), and 36.5 for quartile 4 (>1.84 mmol/l) (P < 0.0001 for trend). These associations remained significant even after adjustment for other risk factors: the multivariable-adjusted hazard ratio was 1.29 (1.01-1.66) for the second quartile, 1.27 (0.99-1.63) for the third quartile, and 1.39 (1.09-1.77) for the highest quartile compared with the lowest. There were comparable effects of serum triglyceride levels for incidence of hypertension between subgroups defined by sex, obesity, and diabetes (all P > 0.1 for interaction), whereas stronger associations were observed for participants under 40 years of age than for those aged 40 or above (P = 0.002 for interaction).

CONCLUSION

Serum triglyceride levels were significantly associated with development of hypertension in a Japanese worksite population.

The impact of triglycerides on glucose tolerance: Lipotoxicity revisited

Elevated plasma triglycerides (TGs) are early key features of conditions associated with a dysregulation in glucose metabolism and may predict the development of type 2 diabetes (T2D) over time. Although the acute ingestion of lipid, either mixed with or shortly before the meal, is neutral or slightly beneficial on glucose tolerance, a short-term increase in plasma TGs induced by either an i.v. lipid infusion or a high-fat diet produces a deterioration of glucose control. Accordingly, chronic lowering of plasma TGs by fibrates improves glucose homeostasis and may also prevent T2D. The chronic effects of the elevation of dietary lipid intake are less clear, particularly in humans, being the quality of fat probably more important than total fat intake. Although on the bases of the available experimental and clinical evidence it cannot be easily disentangled, with respect to elevated non-esterified fatty acids (NEFA) the relative contribution of elevated TGs to glucose homeostasis disregulation seems to be greater and also more plausible. In conclusion, although the association between elevated plasma TGs and impaired glucose tolerance is commonly considered not causative or merely a consequence of NEFA-mediated lipotoxicity, the available data suggest that TGs per se may directly contribute to disorders of glucose metabolism.

PPARα-dependent increase of mouse urine output by gemfibrozil and fenofibrate

While gemfibrozil and fenofibrate are prescribed for anti-dyslipidemia treatment, a rational basis for the use of these drugs for treatment of dyslipidemia with concurrent metabolic syndrome has not been established. In this study, wild-type and Pparα-null mice were fed gemfibrozil- or fenofibrate-containing diets for 14 days. Urine output (24 h) was monitored, and urine, serum, and liver and kidney tissues were subjected to toxicity assessment. A 2-month challenge followed by a 2-week wash-out was performed for gemfibrozil to determine urine output and the potential toxicity. A therapeutically equivalent dose of gemfibrozil was more effective than fenofibrate in increasing urine output. This regulatory effect was not observed in Pparα-null mice. In contrast, hepatomegaly induced by fenofibrate was more pronounced than that of gemfibrozil. No significant toxicity was observed in liver or kidney in the 2-month treatment with gemfibrozil. These data demonstrated PPARα mediates the increased urine output by fibrates. Considering the relative action on hepatomegaly and the regulatory effect on urine output, gemfibrozil may be the preferable drug to increase urine output. These results revealed a new pharmacodynamic effect of clinically prescribed PPARα agonists and suggested the potential value of gemfibrozil in modification of blood pressure.

Bezafibrate Improves Insulin Sensitivity and Metabolic Flexibility in STZ-Induced Diabetic Mice

Bezafibrate (BEZ), a pan activator of peroxisome proliferator-activated receptors (PPARs), has been generally used to treat hyperlipidemia for decades. Clinical trials with type 2 diabetes patients indicated that BEZ also has beneficial effects on glucose metabolism, although the underlying mechanisms of these effects remain elusive. Even less is known about a potential role for BEZ in treating type 1 diabetes. Here we show that BEZ markedly improves hyperglycemia and glucose and insulin tolerance in mice with streptozotocin (STZ)-induced diabetes, an insulin-deficient mouse model of type 1 diabetes. BEZ treatment of STZ mice significantly suppressed the hepatic expression of genes that are annotated in inflammatory processes, whereas the expression of PPAR and insulin target gene transcripts was increased. Furthermore, BEZ-treated mice also exhibited improved metabolic flexibility as well as an enhanced mitochondrial mass and function in the liver. Finally, we show that the number of pancreatic islets and the area of insulin-positive cells tended to be higher in BEZ-treated mice. Our data suggest that BEZ may improve impaired glucose metabolism by augmenting hepatic mitochondrial performance, suppressing hepatic inflammatory pathways, and improving insulin sensitivity and metabolic flexibility. Thus, BEZ treatment might also be useful for patients with impaired glucose tolerance or diabetes.

Early investigational drugs targeting PPAR-α for the treatment of metabolic disease

INTRODUCTION

The fibrates have been used for many years to treat dyslipidemias and have also recently been shown to have anti-inflammatory effects. They are relatively weak PPAR-α agonists and do have some adverse effects. Novel compounds are in development, which are selective PPAR modulators (SPPARMs) and have more potent PPAR-α agonist activity. These may prove to have advantages in the treatment of dyslipidemia, insulin resistance and non-alcoholic fatty liver disease (NAFLD).

AREAS COVERED

This review focuses on PPAR-α agonists or SPPARMs in development describing the preclinical and early clinical studies. The information was obtained by searching the published literature and abstracts from recent meetings. Ongoing clinical trials were identified using the Clinicaltrial.gov database.

EXPERT OPINION

There is still a need for new drugs to treat atherogenic dyslipidemia. The highly potent and selective PPAR-α agonist K-877 has shown beneficial effects on atherogenic dyslipidemia and absence of some adverse effects seen with fibrates. The dual PPAR-α/PPAR-δ agonist GFT-505 has shown favorable results in improving atherogenic dyslipidemia and insulin resistance and appears to be a potential candidate for the treatment of NAFLD. Long-term trials are needed to assess the safety and efficacy of these new agents for cardiovascular and liver outcomes.

Effect of bezafibrate on office, home and ambulatory blood pressure in hypertensive patients with dyslipidemia

It has been suggested that fibrates, lipid-lowering agents with a peroxisome proliferator-activated receptor-α agonistic property, lower blood pressure (BP) in some experimental models of hypertension. However, the effect of fibrates on BP in humans has been inconsistent, and there are few studies using home or ambulatory BP monitoring. We investigated the effects of bezafibrate on office, home and ambulatory BP in hypertensive patients with dyslipidemia. Thirty-two essential hypertensive patients with dyslipidemia (6 men and 26 women, mean age 65±8 years old) were assigned to a control period and a bezafibrate period (200 mg twice daily) for 8 weeks each in a randomized crossover manner. Bezafibrate significantly reduced serum triglyceride, total and low-density lipoprotein-cholesterol, blood glucose, plasma insulin, the homeostasis model assessment ratio and increased high-density lipoprotein-cholesterol. Compared with the control period, changes in office, home and 24-h BP with bezafibrate were -0.7±2.1/-1.6±1.2 mm Hg, +0.9±1.0/-0.5±0.6 and +0.8±1.4/-0.6±0.9 mm Hg, respectively. None of these differences in BP was significant. In conclusion, bezafibrate improved lipid metabolism and insulin sensitivity but did not affect office, home or ambulatory BP in hypertensive patients with dyslipidemia. Fibrates do not appear to lower BP in patients with essential hypertension.

Balanced pan-PPAR activator bezafibrate in combination with statin: comprehensive lipids control and diabetes prevention?

All fibrates are peroxisome proliferators-activated receptors (PPARs)-alpha agonists with ability to decrease triglyceride and increase high density lipoprotein- cholesterol (HDL-C). However, bezafibrate has a unique characteristic profile of action since it activates all three PPAR subtypes (alpha, gamma and delta) at comparable doses. Therefore, bezafibrate operates as a pan-agonist for all three PPAR isoforms. Selective PPAR gamma agonists (thiazolidinediones) are used to treat type 2 diabetes mellitus (T2DM). They improve insulin sensitivity by up-regulating adipogenesis, decreasing free fatty acid levels, and reversing insulin resistance. However, selective PPAR gamma agonists also cause water retention, weight gain, peripheral edema, and congestive heart failure. The expression of PPAR beta/ delta in essentially all cell types and tissues (ubiquitous presence) suggests its potential fundamental role in cellular biology. PPAR beta/ delta effects correlated with enhancement of fatty acid oxidation, energy consumption and adaptive thermogenesis. Together, these data implicate PPAR beta/delta in fuel combustion and suggest that pan-PPAR agonists that include a component of PPAR beta/delta activation might offset some of the weight gain issues seen with selective PPAR gamma agonists, as was demonstrated by bezafibrate studies. Suggestively, on the whole body level all PPARs acting as one orchestra and balanced pan-PPAR activation seems as an especially attractive pharmacological goal. Conceptually, combined PPAR gamma and alpha action can target simultaneously insulin resistance and atherogenic dyslipidemia, whereas PPAR beta/delta properties may prevent the development of overweight. Bezafibrate, as all fibrates, significantly reduced plasma triglycerides and increased HDL-C level (but considerably stronger than other major fibrates). Bezafibrate significantly decreased prevalence of small, dense low density lipoproteins particles, remnants, induced atherosclerotic plaque regression in thoracic and abdominal aorta and improved endothelial function. In addition, bezafibrate has important fibrinogen-related properties and anti-inflammatory effects. In clinical trials bezafibrate was highly effective for cardiovascular risk reduction in patients with metabolic syndrome and atherogenic dyslipidemia. The principal differences between bezafibrate and other fibrates are related to effects on glucose level and insulin resistance. Bezafibrate decreases blood glucose level, HbA1C, insulin resistance and reduces the incidence of T2DM compared to placebo or other fibrates. Currently statins are the cornerstone of the treatment and prevention of cardiovascular diseases related to atherosclerosis. However, despite the increasing use of statins as monotherapy for low density lipoprotein- cholesterol (LDL-C) reduction, a significant residual cardiovascular risk is still presented in patients with atherogenic dyslipidemia and insulin resistance, which is typical for T2DM and metabolic syndrome. Recently, concerns were raised regarding the development of diabetes in statin-treated patients. Combined bezafibrate/statin therapy is more effective in achieving a comprehensive lipid control and residual cardiovascular risk reduction. Based on the beneficial effects of pan-PPAR agonist bezafibrate on glucose metabolism and prevention of new-onset diabetes, one could expect a neutralization of the adverse pro-diabetic effect of statins using the strategy of a combined statin/fibrate therapy.

Balanced pan-PPAR activator bezafibrate in combination with statin: comprehensive lipids control and diabetes prevention?

All fibrates are peroxisome proliferators-activated receptors (PPARs)-alpha agonists with ability to decrease triglyceride and increase high density lipoprotein- cholesterol (HDL-C). However, bezafibrate has a unique characteristic profile of action since it activates all three PPAR subtypes (alpha, gamma and delta) at comparable doses. Therefore, bezafibrate operates as a pan-agonist for all three PPAR isoforms. Selective PPAR gamma agonists (thiazolidinediones) are used to treat type 2 diabetes mellitus (T2DM). They improve insulin sensitivity by up-regulating adipogenesis, decreasing free fatty acid levels, and reversing insulin resistance. However, selective PPAR gamma agonists also cause water retention, weight gain, peripheral edema, and congestive heart failure. The expression of PPAR beta/ delta in essentially all cell types and tissues (ubiquitous presence) suggests its potential fundamental role in cellular biology. PPAR beta/ delta effects correlated with enhancement of fatty acid oxidation, energy consumption and adaptive thermogenesis. Together, these data implicate PPAR beta/delta in fuel combustion and suggest that pan-PPAR agonists that include a component of PPAR beta/delta activation might offset some of the weight gain issues seen with selective PPAR gamma agonists, as was demonstrated by bezafibrate studies. Suggestively, on the whole body level all PPARs acting as one orchestra and balanced pan-PPAR activation seems as an especially attractive pharmacological goal. Conceptually, combined PPAR gamma and alpha action can target simultaneously insulin resistance and atherogenic dyslipidemia, whereas PPAR beta/delta properties may prevent the development of overweight. Bezafibrate, as all fibrates, significantly reduced plasma triglycerides and increased HDL-C level (but considerably stronger than other major fibrates). Bezafibrate significantly decreased prevalence of small, dense low density lipoproteins particles, remnants, induced atherosclerotic plaque regression in thoracic and abdominal aorta and improved endothelial function. In addition, bezafibrate has important fibrinogen-related properties and anti-inflammatory effects. In clinical trials bezafibrate was highly effective for cardiovascular risk reduction in patients with metabolic syndrome and atherogenic dyslipidemia. The principal differences between bezafibrate and other fibrates are related to effects on glucose level and insulin resistance. Bezafibrate decreases blood glucose level, HbA1C, insulin resistance and reduces the incidence of T2DM compared to placebo or other fibrates. Currently statins are the cornerstone of the treatment and prevention of cardiovascular diseases related to atherosclerosis. However, despite the increasing use of statins as monotherapy for low density lipoprotein- cholesterol (LDL-C) reduction, a significant residual cardiovascular risk is still presented in patients with atherogenic dyslipidemia and insulin resistance, which is typical for T2DM and metabolic syndrome. Recently, concerns were raised regarding the development of diabetes in statin-treated patients. Combined bezafibrate/statin therapy is more effective in achieving a comprehensive lipid control and residual cardiovascular risk reduction. Based on the beneficial effects of pan-PPAR agonist bezafibrate on glucose metabolism and prevention of new-onset diabetes, one could expect a neutralization of the adverse pro-diabetic effect of statins using the strategy of a combined statin/fibrate therapy.

Relaxation of rat thoracic aorta by fibrate drugs correlates with their potency to disturb intracellular calcium of VSMCs

Phenotypic modifications of vascular smooth muscle cells (VSMCs) contribute to pathological changes in atherosclerosis where modulation of intracellular calcium plays an important role. In this study, three fibrate drugs, namely gemfibrozil (Gem), fenofibric acid (Fa) and bezafibrate (Beza), were revealed to relax thoracic aorta associated with their potency to reduce intracellular calcium ([Ca²⁺]i) in cultured VSMCs. Relaxation effect of Gem, Fa and Beza was assayed on precontracted rat aortic rings. [Ca²⁺]i level in VSMCs following addition of these fibrates was measured by laser scanning confocal microscopy or flow cytometry. Resultantly, three fibrates showed activity for vasodilation with potency order of Gem>Fa>Beza. Sustained potent reduction of [Ca²⁺]i was observed with Gem 50mg/L and mild reduction with Fa 400-600mg/L, while no effect had been detected for Beza under our current system. Thus, the potency of these fibrates to relax aortic rings correlate well with their effect on [Ca²⁺]i reduction, strongly implicating an underlying causal relationship. Considering that Gem potently reduces [Ca²⁺]i in its clinical concentration range, this study suggests an insight to in situ pharmacological effects of anti-atherosclerosis and clinical toxicity risk.

Increases in mitochondrial biogenesis impair carcinogenesis at multiple levels

Although mitochondrial respiration is decreased in most cancer cells, the role of this decrease in carcinogenesis and cancer progression is still unclear. To better understand this phenomenon, instead of further inhibiting mitochondrial function, we induced mitochondrial biogenesis in transformed cells by activating the peroxisome proliferator-activated receptors (PPARs)/peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α) pathways. This was achieved by treating the cells with bezafibrate, a PPARs panagonist that also enhances PGC-1α expression. We confirmed that bezafibrate treatment led to increased mitochondrial proteins and enzyme functions. We found that cells with increased mitochondrial biogenesis had decreased growth rates in glucose-containing medium. In addition, they became less invasive, which was directly linked to the reduced lactate levels. Surprisingly, even though bezafibrate-treated cells had higher levels of mitochondrial markers, total respiration was not significantly altered. However, respiratory coupling, and ATP levels were. Our data show that by increasing the efficiency of the mitochondrial oxidative phosphorylation system, cancer progression is hampered by decreases in cell proliferation and invasiveness.

Evidence of direct smooth muscle relaxant effects of the fibrate gemfibrozil

Fibrates are commonly employed to treat abnormal lipid metabolism via their unique ability to stimulate peroxisome proliferator-activated receptor alpha (PPARalpha). Interestingly, they also decrease systemic arterial pressure, despite recent evidence that PPAR alpha may contribute to expression of renin and related hypertension. Yet, mechanisms responsible for their potential antihypertensive activity remain unresolved. Rapid decreases in arterial pressure following bolus intravenous injections of bezafibrate strongly suggest they may relax arterial smooth muscle directly. But since bezafibrate is highly susceptible to photodegradation in aqueous media, it has never been critically tested for this possibility in vitro with isolated arterial smooth muscle preparations. Accordingly, we tested gemfibrozil which is resistant to photodegradation. We examined it over a therapeutically-relevant range (50-400 microM) for both acute and delayed relaxant effects on contractions of the isolated rat tail artery; contractions induced by either depolarizing its smooth muscle cell membranes with high potassium or stimulating its membrane-bound receptors with norepinephrine and arginine-vasopressin. We also examined these same gemfibrozil levels for effects on spontaneously-occurring phasic rhythmic contractile activity, typically not seen in arteries under in vitro conditions but commonly exhibited by smooth muscle of uterus, duodenum and bladder. We found that gemfibrozil significantly relaxed all induced forms of contraction in the rat tail artery, acutely at the higher test levels and after a delay of a few hours at the lower test levels. The highest test level of gemfibrozil (400 microM) also completely abolished spontaneously-occurring contractile activity of the isolated uterus and duodenum and markedly suppressed it in the bladder. This is the first evidence that a fibrate drug can directly relax smooth muscle contractions, either induced by various contractile agents or spontaneously-occurring. These findings are particularly relevant to both the recently renewed concern over the impact of fibrates on hypertension and a new understanding of their gastrointestinal side effects.

Omega 3 polyunsaturated fatty acids supplementation and blood pressure levels in hypertriglyceridemic patients with untreated normal-high blood pressure and with or without metabolic syndrome: a retrospective study

Recent evidence suggests that at least a part of the polyunsaturated fatty acids (PUFAs) heart protective effect is mediated by a relatively small but significant decrease in blood pressure level. We retrospectively evaluated the long-term effect of a PUFA supplementation on the blood pressure level of 111 hypertriglyceridemic subjects with untreated normal-high blood pressure that were prescribed a 2 grams PUFA supplementation in order to improve their plasma lipid pattern. After 12 months of treatment, systolic blood pressure (SBP) meanly decreased by 2.7 +/- 2.5 mmHg (p = 0.001) and diastolic blood pressure (DBP) by 1.3 +/- 3.3 mmHg (p < 0.001), while basal heart rate decreased by 4.0 +/- 4.4 bpm (p < 0.001). Both SBP and DBP reduction were significantly related to the baseline SBP (p < 0.001) and DBP (p < 0.001), respectively. Diastolic blood pressure change was also inversely related to the patient's age (p = 0.004). No significant difference was perceived in the metabolic syndrome subgroup. In our retrospective study, highly purified omega-3 PUFA long-term supplementation is associated with a significant reduction in SBP, DBP, Pulse pressure (PP), and basal heart rate in hypertriglyceridemic patients with normal-high blood pressure. No significant difference was perceived in the metabolic syndrome subgroup. The main determinants of the PUFA anti-hypertensive effect appear to be the basal blood pressure level and age.

Bezafibrate mildly stimulates ketogenesis and fatty acid metabolism in hypertriglyceridemic subjects

Our objective was to determine whether bezafibrate, a hypotriglyceridemic drug and peroxisome proliferator-activated receptor (PPAR)-alpha agonist, is ketogenic and increases fatty acid oxidation in humans. We measured fatty acid metabolism and ketone levels in 13 mildly hypertriglycemic adults (67 +/- 11 years old) during 2 metabolic study days lasting 6 h, 1 day before and 1 day after bezafibrate (400 mg of bezafibrate per day for 12 weeks). beta-Hydroxybutyrate, triglycerides, free fatty acids, fatty acid profiles, insulin, and glucose were measured in plasma, and fatty acid beta-oxidation was measured in breath after an oral 50-mg dose of the fatty acid tracer [U-(13)C]linoleic acid. As expected, 12 weeks on bezafibrate decreased plasma triglycerides by 35%. Bezafibrate tended to raise postprandial beta-hydroxybutyrate, an effect that was significant after normalization to the fasting baseline values (p = 0.03). beta-Oxidation of [U-(13)C]linoleic acid increased by 30% (p = 0.03) after treatment. On the metabolic study day after bezafibrate treatment, postprandial insulin decreased by 26% (p = 0.01), and glucose concentrations were lower 2 to 5 h postprandially. Thus, in hypertriglyceridemic individuals, bezafibrate is mildly ketogenic and significantly changes fatty acid metabolism, effects that may be linked to PPARalpha stimulation and to moderately improved glucose metabolism.

Cholesterol reduction and atherosclerosis inhibition by bezafibrate in low-density lipoprotein receptor knockout mice

Fibrates, peroxisome proliferator-activated receptor a agonists, are widely used as lipid-lowering agents with anti-atherogenic activity. However, conflicting results have been reported with regard to their pharmacological effects on plasma lipoprotein profiles as well as on atherosclerosis in animal models. Furthermore, the anti-atherogenic effects of bezafibrate, one of the most commonly used fibrates, in animal models have not been reported. In the present study, we investigated the effects of bezafibrate on lipoprotein profiles as well as on atherosclerosis in low-density lipoprotein receptor knockout (LDLR-/-) mice fed an atherogenic diet for 8 weeks. Bezafibrate decreased plasma levels of both cholesterol and triglycerides (TG), while increasing plasma levels of high-density lipoprotein-cholesterol (HDL-C). Since hepatic TG production was significantly reduced in the bezafibrate-treated mice lacking LDLR, the plasma lipid-lowering effects of bezafibrate might be primarily mediated by the suppression of hepatic production of apolipoprotein-B-containing lipoproteins. In parallel with the reduced ratio of non-HDL-C to HDL-C, bezafibrate suppressed fatty streak lesions in the aortic sinus by 51%. To determine whether or not bezafibrate directly alters the expression of genes relevant to atherosclerosis, we measured mRNA expression levels of three genes in the aorta by real-time PCR: ATP-binding cassette transporter A1, lipoprotein lipase, and monocyte chemoattractant protein-1. The results showed that there were no differences in the expression of these genes between mice treated with bezafibrate and those not. In conclusion, bezafibrate inhibits atherosclerosis in LDLR-/- mice primarily by decreasing the ratio of non-HDL-C to HDL-C.

Positive Association Between Plasma Fibrinogen Level and Incident Hypertension Among Men

Elevated plasma fibrinogen is implicated in cardiovascular disease. However, it is not clear whether fibrinogen levels predict the development of hypertension. We examined the relationship between plasma fibrinogen level and hypertension in a population-based cohort study of 3654 participants (mean age: 61.5 years; range: 49 to 84 years) at the baseline examination (1992-1994) in the Blue Mountains region, west of Sydney, Australia, who were examined 5 years (1997-1999) later. Main outcomes of interest were prevalent hypertension (systolic blood pressure >or=140 mm Hg, diastolic blood pressure >or=90 mm Hg, or a combination of self-reported hypertension diagnosis and use of antihypertensive medications) at baseline (n=2212/3180) and 5-year incidence of hypertension among baseline normotensive individuals (n=361/637). Elevated plasma fibrinogen level was positively associated with prevalent hypertension both among men and women and positively associated with 5-year incident hypertension among men, independent of several cardiovascular risk factors. Multivariable odds ratio (95% CI) of 5-year incident hypertension comparing tertile 3 of plasma fibrinogen (>or=3.9 g/L) with tertile 1 (<or=3.2 g/L) was 1.95 (1.03 to 3.68; P trend=0.040). This prospective association, however, was not observed in women (odds ratio; 95% CI) comparing tertile 3 versus tertile 1 of plasma fibrinogen (1.00; 0.54 to 1.86; P trend=0.986). Subgroup analyses stratified by smoking, body mass index, diabetes, and blood pressure categories supported this male gender-specific pattern of association. These data provide prospective epidemiological evidence of an essential link between plasma fibrinogen level and incident hypertension among men but not among women, a finding consistent with that observed in the Atherosclerosis Risk in Communities Study.

Long-term effect of bezafibrate on pancreatic beta-cell function and insulin resistance in patients with diabetes

OBJECTIVE

Development of insulin resistance (IR) and the progressive failure of the pancreatic beta-cell function (BCF) may be important in the pathogenesis of type 2 diabetes. Influence of peroxisome proliferator-activated receptors ligand bezafibrate on BCF and IR in patients with diabetes is unknown. The present study was aimed to investigate the long-term effect of bezafibrate on these parameters in diabetic patients enrolled in the Bezafibrate Infarction Prevention (BIP) Study.

METHODS

Metabolic and inflammatory parameters were analyzed from stored frozen plasma samples obtained from 351 diabetic patients (168 treated by bezafibrate and 183 by placebo) who completed a 2-year of randomized, double-blind, placebo-controlled study period. The homeostatic indexes of BCF (HOMA-BCF) and IR (HOMA-IR) were calculated according to the homeostasis model of assessment.

RESULTS

Both groups displayed similar baseline characteristics. During follow-up, in the placebo group there was 28% rise of HOMA-IR (p<0.001). In contrast, HOMA-IR in patients in the bezafibrate group did not change (p=0.99). The intergroup differences in HOMA-IR percentage changes were in favor of bezafibrate (p=0.01). HOMA-BCF values have significantly decreased by 13.9% (p=0.04) in patients of placebo group, whereas in patients of bezafibrate group HOMA-BCF was stable during follow-up and its alterations (-2.9%) were non-significant (p=0.59).

CONCLUSIONS

Diabetic patients from the placebo group demonstrated a progressive declining of BCF and an increasing of IR over 2 years of follow-up. These longitudinal changes were attenuated when patients used bezafibrate.

Inhibitory effect of insulin on vasopressin-induced intracellular calcium response is blunted in hyperinsulinemic hypertensive patients: role of membrane fatty acid composition

Impaired insulin-mediated vasodilation has been implicated in hypertension that is associated with the metabolic syndrome. The aim of this study was to determine whether an abnormality in membrane fatty acid composition was related to a weakening of insulin's inhibitory effect on agonist-stimulated intracellular free calcium elevation. Mild to moderate hypertensive patients (n = 27) and normotensive controls (n = 11) were studied. Hypertensive patients were divided into normoinsulinemic patients (n = 14) and hyperinsulinemic patients (n = 13) according to the area under the curve of plasma insulin concentrations during a 75-g oral glucose tolerance test. Nonstimulated and arginine-vasopressin (AVP) (1 micromol/l)-stimulated intraplatelet free calcium concentrations (p[Ca(2+)](i)) were measured with or without insulin (100 microU/ml) preincubation. Platelet membrane fatty acid composition, intraerythrocyte sodium content, and the ouabain-sensitive sodium efflux rate constant (K (os)) of erythrocytes were also determined. Insulin preincubation reduced AVP-stimulated p[Ca(2+)](i) elevation in both normotensive controls and hypertensive patients. The inhibitory effect of insulin on AVP-stimulated elevation of p[Ca(2+)](i) (%Inhibition) was significantly (P < 0.05) blunted in hyperinsulinemic hypertensive patients (9.7% +/- 2.4%) as compared to normoinsulinemic hypertensive patients (17.4% +/- 2.7%) and normotensive controls (16.9% +/- 1.7%). In hypertensive patients, the %Inhibition was correlated negatively with saturated fatty acids (SFA) (r = -0.51, P < 0.05) and systolic blood pressure (r = -0.44, P < 0.05), and correlated positively with membrane polyunsaturated fatty acids (PUFA) (r = 0.53, P < 0.01) and K (os) (r = 0.53, P < 0.005). Multiple regression analysis showed that SFA, PUFA, and K (os) were the significant variables for %Inhibition. These findings indicate that an increase in SFA and a decrease in PUFA may cause insulin insensitivity in cellular calcium and sodium handling in hypertension with hyperinsulinemia.

Renoprotective effect of pravastatin in salt-loaded Dahl salt-sensitive rats

The pathophysiological features of nephrosclerosis may be analogous to those of atherosclerosis, which is intimately related to lipid metabolism. Thus, we examined whether a lipid-lowering agent, pravastatin, would ameliorate renal damage in hypertensive model animals. Salt-loaded Dahl salt-sensitive (S) rats were given pravastatin (2 mg/ml in drinking water) for 5 weeks. Pravastatin decreased systolic blood pressure. Although pravastatin did not influence the serum total, high-density, or low-density lipoprotein cholesterol, serum triglycerides were decreased. Pravastatin decreased urinary protein excretion and ameliorated histopathological damage in salt-loaded Dahl S rats. Increased urinary excretion of 8-iso-prostagaldin F2alpha and 8-hydroxy-2'-deoxyguanosine and renal superoxide overproduction and decreased reduced glutathione in the renal parenchyma were ameliorated with pravastatin in Dahl S rats fed a high salt diet. Therefore, pravastatin inhibited the progression of renal injury in salt-loaded Dahl S rats, through its antioxidant as well as its depressor effects.

Lipid therapy for cardiovascular disease with insulin resistance, diabetes, or the metabolic syndrome

Insulin resistance with the development of diabetes or metabolic syndrome is associated with characteristic lipid abnormalities and an increased likelihood of cardiovascular events. This review examines the rationale and clinical trial evidence for the benefit of lipid drug therapy in the presence of these related high-risk conditions. In particular, the results of the more recent statin trials are discussed and contrasted with evidence from trials with fibrates, which, although fewer in number, appear to show that this particular therapy has selective benefit for the overweight individual with diabetes or features of the metabolic syndrome.

Dual and pan-peroxisome proliferator-activated receptors (PPAR) co-agonism: the bezafibrate lessons

There are three peroxisome proliferator-activated receptors (PPARs) subtypes which are commonly designated PPAR alpha, PPAR gamma and PPAR beta/delta. PPAR alpha activation increases high density lipoprotein (HDL) cholesterol synthesis, stimulates "reverse" cholesterol transport and reduces triglycerides. PPAR gamma activation results in insulin sensitization and antidiabetic action. Until recently, the biological role of PPAR beta/delta remained unclear. However, treatment of obese animals by specific PPAR delta agonists results in normalization of metabolic parameters and reduction of adiposity. Combined treatments with PPAR gamma and alpha agonists may potentially improve insulin resistance and alleviate atherogenic dyslipidemia, whereas PPAR delta properties may prevent the development of overweight which typically accompanies "pure" PPAR gamma ligands. The new generation of dual-action PPARs – the glitazars, which target PPAR-gamma and PPAR-alpha (like muraglitazar and tesaglitazar) are on deck in late-stage clinical trials and may be effective in reducing cardiovascular risk, but their long-term clinical effects are still unknown. A number of glitazars have presented problems at a late stage of clinical trials because of serious side-effects (including ragaglitazar and farglitazar). The old and well known lipid-lowering fibric acid derivative bezafibrate is the first clinically tested pan – (alpha, beta/delta, gamma) PPAR activator. It is the only pan-PPAR activator with more than a quarter of a century of therapeutic experience with a good safety profile. Therefore, bezafibrate could be considered (indeed, as a "post hoc" understanding) as an "archetype" of a clinically tested pan-PPAR ligand. Bezafibrate leads to considerable raising of HDL cholesterol and reduces triglycerides, improves insulin sensitivity and reduces blood glucose level, significantly lowering the incidence of cardiovascular events and new diabetes in patients with features of metabolic syndrome. Clinical evidences obtained from bezafibrate-based studies strongly support the concept of pan-PPAR therapeutic approach to conditions which comprise the metabolic syndrome. However, from a biochemical point of view, bezafibrate is a PPAR ligand with a relatively low potency. More powerful new compounds with pan-PPAR activity and proven long-term safety should be highly effective in a clinical setting of patients with coexisting relevant lipid and glucose metabolism disorders.

Fructose-induced fatty liver disease: hepatic effects of blood pressure and plasma triglyceride reduction

The most known risk factor for nonalcoholic fatty liver disease (NAFLD) is the metabolic syndrome. In this study, we characterized changes in liver pathology, hepatic lipid composition, and hepatic iron concentration (HIC) occurring in rats given fructose-enriched diet (FED), with and without therapeutic maneuvers to reduce blood pressure and plasma triglycerides. Rats were given FED or standard rat chow for 5 weeks. Rats on FED were divided into 4 groups: receiving amlodipine (15 mg/kg per day), captopril (90 mg/kg per day), bezafibrate (10 mg/kg per day) in the last 2 weeks, or a control group that received FED only. FED rats had hepatic macrovesicular and microvesicular fat deposits develop, with increase in hepatic triglycerides (+198%) and hepatic cholesterol (+89%), but a decrease in hepatic phospholipids (-36%), hypertriglyceridemia (+223%), and hypertension (+15%), without increase in HIC. Amlodipine reduced blood pressure (-18%), plasma triglycerides (-12%), but there was no change in hepatic triglycerides and phospholipids concentrations. Captopril reduced blood pressure (-24%), plasma triglycerides (-36%), hepatic triglycerides (-51%), and hepatic macrovesicular fat (-51%), but increased HIC (+23%), with a borderline increase in hepatic fibrosis. Bezafibrate reduced plasma triglycerides (-49%), hepatic triglycerides (-78%), hepatic macrovesicular fat (-90%), and blood pressure (-11%). We conclude that FED rats can be a suitable model for human NAFLD. Drugs administered to treat various aspects of the metabolic syndrome could have hepatic effects. An increase in HIC in rats with NAFLD could be associated with increased hepatic fibrosis.

Elevation of C-reactive protein in people with prehypertension

The objective of this study was to determine the relationship of C-reactive protein (CRP) and blood pressure (BP) across the range of BP categories including prehypertension. The Third National Health and Nutrition Examination Survey (NHANES III) data collected from 1988 to 1994 were analyzed. In unadjusted analyses, there was a step-wise increase in the probability of elevated CRP across a wide range of BP categories. Prehypertensive participants had a higher prevalence of elevated CRP than normotensive people (27.4% vs. 19.8%; p<05). After adjustment for age, gender, race, smoking, body mass index, exercise, diabetes, and medication usage, participants with systolic BP 120-139 mm Hg or diastolic BP 80-89 mm Hg were more likely to have elevated CRP than people with systolic BP <120 (odds ratio, 1.36; 95% confidence interval, 1.14-1.62; odds ratio, 1.20; 95% confidence interval, 1.02-1.41, respectively). CRP and BP are positively related across a wide range of BP categories. A substantial proportion of prehypertensive individuals have elevated CRP independent of multiple confounders.

Thiazolidinedione Effects on Blood Pressure in Diabetic Patients with Metabolic Syndrome Treated with Glimepiride

The aim of our study was to compare the long-term effect of pioglitazone and rosiglitazone on blood pressure control of diabetic patients with metabolic syndrome treated with glimepiride. We evaluated 91 type 2 diabetic patients with metabolic syndrome. All were required to have been diagnosed as diabetic for at least 6 months, and to have failed to achieve glycemic control by dietary changes and the maximum tolerated dose of the oral hypoglycemic agents sulfonylureas or metformin. All patients took a fixed dose of 4 mg/day glimepiride. We administered pioglitazone (15 mg/day) or rosiglitazone (4 mg/day) for 12 months in a randomized, double-blind fashion, and evaluated body mass index (BMI), glycemic control, blood pressure and heart rate (HR) throughout the treatment period. A total of 87 patients completed the study and were randomized to receive double-blind treatment with pioglitazone or rosiglitazone. An increase in BMI was observed after 12 months (p < 0.05) in both groups. After 9 and 12 months, there were significant decreases in glycated hemoglobin (HbA(1c)), mean fasting plasma glucose (FPG), postprandial plasma glucose (PPG), fasting plasma insulin (FPI), and postprandial plasma insulin (PPI) in both treatment groups (p < 0.05 at 9 months and p < 0.01 at 12 months for all parameters). Furthermore, homeostasis model assessment index (HOMA index) improvement was obtained at 9 and 12 months (p < 0.05 and p < 0.01, respectively) in both groups. Significant systolic blood pressure (SBP) and diastolic blood pressure (DBP) improvement (p < 0.05, respectively) was observed in both groups after 12 months. There were no significant changes in transaminases at any point during the study. We can conclude that the association of a thiazolinedione to the glimepiride treatment of type 2 diabetic subjects with metabolic syndrome is associated to a significant improvement in the long-term blood pressure control, related to a reduction in insulin-resistance.

Olmesartan Medoxomil, an Angiotensin II Receptor Blocker Ameliorates Insulin Resistance and Decreases Triglyceride Production in Fructose-Fed Rats

Although angiotensin II receptor blockers (ARBs) have been recommended as a first line of anti-hypertensive agents in patients with diabetes, it remains unclear whether ARBs have a favorable effect on insulin action and triglyceride (TG) metabolism, both of which are impaired in type 2 diabetes. In this study we addressed this issue by investigating how a newly developed ARB, olmesartan medoxomil, influenced insulin sensitivity and TG metabolism in fructose-fed rats, a representative animal model of insulin resistance. Olmesartan was administrated as a 0.01% drinking solution ad libitum to rats either fed normal chow or fructose-enriched chow (60%) for 21 days. Olmesartan treatment markedly decreased both systolic and diastolic blood pressure in both chow-fed and fructose-fed animals. The area under the curve of insulin (AUCI) was substantially greater in fructose-fed rats in the intravenous glucose tolerance test, and olmesartan treatment significantly reduced the AUCI. Olmesartan significantly improved the insulin sensitivity index in fructose-fed rats assessed by Bergman's minimal model without affecting insulin-independent glucose disposal. Olmesartan significantly decreased plasma TG and non-esterified fatty acid levels in fructose-fed rats without affecting lipoprotein lipase mass. The TG secretion rate determined by the triton WR1339 technique was two-fold higher in fructose-fed rats, but olmesartan restored the TG secretion to a normal rate. Olmesartan did not affect plasma parameters, insulin sensitivity or TG metabolism in chow-fed rats. Olmesartan ameliorates insulin resistance and overproduction of TG in fructose-fed rats, and these effects appear to be independent of its hypotensive action.