Effects of fluvastatin treatment on red blood cell Na+ transport systems in hypercholesterolemic subjects

Fluvastatin for lowering lipids

BACKGROUND

Fluvastatin is thought to be the least potent statin on the market, however, the dose-related magnitude of effect of fluvastatin on blood lipids is not known.

OBJECTIVES

Primary objectiveTo quantify the effects of various doses of fluvastatin on blood total cholesterol, low-density lipoprotein (LDL cholesterol), high-density lipoprotein (HDL cholesterol), and triglycerides in participants with and without evidence of cardiovascular disease.Secondary objectivesTo quantify the variability of the effect of various doses of fluvastatin.To quantify withdrawals due to adverse effects (WDAEs) in randomised placebo-controlled trials.

SEARCH METHODS

The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to February 2017: the Cochrane Central Register of Controlled Trials (CENTRAL) (2017, Issue 1), MEDLINE (1946 to February Week 2 2017), MEDLINE In-Process, MEDLINE Epub Ahead of Print, Embase (1974 to February Week 2 2017), the World Health Organization International Clinical Trials Registry Platform, CDSR, DARE, Epistemonikos and ClinicalTrials.gov. We also contacted authors of relevant papers regarding further published and unpublished work. No language restrictions were applied.

SELECTION CRITERIA

Randomised placebo-controlled and uncontrolled before and after trials evaluating the dose response of different fixed doses of fluvastatin on blood lipids over a duration of three to 12 weeks in participants of any age with and without evidence of cardiovascular disease.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility criteria for studies to be included, and extracted data. We entered data from placebo-controlled and uncontrolled before and after trials into Review Manager 5 as continuous and generic inverse variance data, respectively. WDAEs information was collected from the placebo-controlled trials. We assessed all trials using the 'Risk of bias' tool under the categories of sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting, and other potential biases.

MAIN RESULTS

One-hundred and forty-five trials (36 placebo controlled and 109 before and after) evaluated the dose-related efficacy of fluvastatin in 18,846 participants. The participants were of any age with and without evidence of cardiovascular disease, and fluvastatin effects were studied within a treatment period of three to 12 weeks. Log dose-response data over doses of 2.5 mg to 80 mg revealed strong linear dose-related effects on blood total cholesterol and LDL cholesterol and a weak linear dose-related effect on blood triglycerides. There was no dose-related effect of fluvastatin on blood HDL cholesterol. Fluvastatin 10 mg/day to 80 mg/day reduced LDL cholesterol by 15% to 33%, total cholesterol by 11% to 25% and triglycerides by 3% to 17.5%. For every two-fold dose increase there was a 6.0% (95% CI 5.4 to 6.6) decrease in blood LDL cholesterol, a 4.2% (95% CI 3.7 to 4.8) decrease in blood total cholesterol and a 4.2% (95% CI 2.0 to 6.3) decrease in blood triglycerides. The quality of evidence for these effects was judged to be high. When compared to atorvastatin and rosuvastatin, fluvastatin was about 12-fold less potent than atorvastatin and 46-fold less potent than rosuvastatin at reducing LDL cholesterol. Very low quality of evidence showed no difference in WDAEs between fluvastatin and placebo in 16 of 36 of these short-term trials (risk ratio 1.52 (95% CI 0.94 to 2.45).

AUTHORS' CONCLUSIONS

Fluvastatin lowers blood total cholesterol, LDL cholesterol and triglyceride in a dose-dependent linear fashion. Based on the effect on LDL cholesterol, fluvastatin is 12-fold less potent than atorvastatin and 46-fold less potent than rosuvastatin. This review did not provide a good estimate of the incidence of harms associated with fluvastatin because of the short duration of the trials and the lack of reporting of adverse effects in 56% of the placebo-controlled trials.

Sodium-lithium countertransport activity in healthy, dyslipidemic, and hypertensive individuals

The aim of our study was to investigate the role of dyslipidemia on red blood cell sodium-lithium countertransport activity in healthy and hypertensive individuals. A total of 128 Caucasian individuals, aged 20 to 60 years old, were divided into 4 groups: dyslipidemic/ hypertensive, dyslipidemic/normotensive, normolipidemic/hypertensive, and normolipidemic/ normotensive (controls). Sodium-lithium countertransport activity was determined based on the Canessa et al method. Sodium-lithium countertransport activity was significantly higher in all patient groups compared with controls (P < .001) and similar in the 3 patient groups. Sodium-lithium countertransport activity was significantly and positively associated with triglyceride levels (P < .001), body mass index (P < .001), total cholesterol levels (P = .001), and systolic (P = .001) and diastolic blood pressure (P = .001). In multivariate regression analysis, triglycerides made the largest contribution to sodium-lithium countertransport variation among the variables tested (R(2) = 0.273). Our results suggest that dyslipidemia affects sodium-lithium countertransport activity independently of essential hypertension and even to a greater extent than hypertension.

Effects of atorvastatin on red-blood cell Na(+)/Li(+) countertransport in hyperlipidemic patients with and without hypertension

BACKGROUND

To explore the effect of short-term cholesterol-lowering treatment with atorvastatin on erythrocyte sodium-lithium countertransport (Na(+)/Li(+) CT) activity.

METHODS

Group A consisted of 30 patients (14 men) with mild essential hypertension (systolic blood pressure (SBP), 140-159 mm Hg and/or diastolic BP, 90-99 mm Hg) and primary hypercholesterolemia low-density lipoprotein (LDL) cholesterol >4.1 mmol/l and triglycerides (TG) <2.8 mmol/l), group B of 30 normotensive patients (16 men) with primary hypercholesterolemia, while 37 (18 men) healthy volunteers comprised the control group. After a 6-week dietary lead-in, all eligible patients were prescribed 20 mg/day of atorvastatin. Anthropometric data, blood-pressure (BP) measurements and determinations of lipid, non-lipid metabolic parameters (including homeostasis model assessment index, (HOMA-IR)) and erythrocyte Na(+)/Li(+) CT activity were collected at baseline and after 12 weeks of treatment.

RESULTS

At baseline Na(+)/Li(+) CT activity was significantly higher in group A and B compared with the control group and correlated directly with obesity indices, systolic and diastolic BP, total cholesterol, LDL-cholesterol, TG, apolipoprotein B (apoB), HOMA-IR, uric acid and inversely with high-density lipoprotein (HDL)-cholesterol and apoA1. Systolic and diastolic BP levels, HOMA-IR and Na(+)/Li(+) CT activity were significantly decreased after atorvastatin treatment in both patient groups. The reduction in Na(+)/Li(+) CT activity correlated with baseline Na(+)/Li(+) CT activity and the changes in HOMA-IR values.

CONCLUSIONS

Short-term treatment with atorvastatin for patients with hypercholesterolemia, and with or without essential hypertension, is associated with a significant reduction in the erythrocyte Na(+)/Li(+) CT activity, BP levels and insulin resistance independent of concomitant changes in lipid parameters.

Effect of acute hyperglycemia on erythrocyte membrane ion transport in offspring of hypertensive parents

OBJECTIVE

Patients with essential hypertension exhibit several red blood cell (RBC) ion transport abnormalities, insulin resistance (IR) and increased risk of developing type 2 diabetes. The aims of this study were to assess RBC ion transport activities under basal conditions and to test the in vivo effect of acute hyperglycemia on RBC ion transport in the offspring of hypertensive parents (OHP) and healthy controls (C).

DESIGN AND METHODS

Activities of Na+-K+ pump, Na+-K+ cotransport, Na+-Li+ countertransport (SLC) and Na+, Rb+ and Li+ leaks were measured before and after a 5-h hyperglycemic (12 mmol/l) clamp (HGC) and compared to values found under euglycemic isovolumic conditions in OHP (n = 12) and C (n = 14). Insulin action was calculated as insulin sensitivity index (M/I) during HGC.

RESULTS

The offspring of hypertensive parents were characterized by lower M/I (0.07 +/- 0.03 versus 0.12 +/- 0.07 mg/kg per min per microU per ml; P < 0.05) and elevated SLC (0.080 +/- 0.004 versus 0.068 +/- 0.003 mmol/h per litre; P < 0.05), as well as by higher Li+ (0.106 +/- 0.004 versus 0.093 +/- 0.003 mmol/h per litre; P < 0.05) and Rb+ leaks (0.160 +/- 0.014 versus 0.120 +/- 0.007 mmol/h per litre; P < 0.05) compared to controls. Acute hyperglycemia did not cause significant changes in any investigated RBC ion transport parameters.

CONCLUSIONS

The offspring of hypertensive parents displayed higher insulin resistance, enhanced activity of SLC and formerly undocumented augmented Li+ and Rb+ leaks. Acute hyperglycemia did not modify any RBC ion transport activities in either offspring of hypertensive parents or controls.