Comparison of SGLT2 inhibitors vs. DPP4 inhibitors for patients with metabolic dysfunction associated fatty liver disease and diabetes mellitus.

PURPOSE: This study aimed to examine the potential benefit of sodium-glucose cotransporter 2 (SGLT2) inhibitors for patients with metabolic dysfunction-associated fatty liver disease (MAFLD) and diabetes mellitus (DM) using a real-world database. METHODS: We analyzed individuals with MAFLD and DM newly initiated on SGLT2 or dipeptidyl peptidase 4 (DPP4) inhibitors from a large-scale administrative claims database. The primary outcome was the change in the fatty liver index (FLI) assessed using a linear mixed-effects model from the initiation of SGLT2 or DPP4 inhibitors. A propensity score-matching algorithm was used to compare the change in FLI among SGLT2 and DPP4 inhibitors. RESULTS: After propensity score matching, 6547 well-balanced pairs of SGLT2 and 6547 DPP4 inhibitor users were created. SGLT2 inhibitor use was associated with a greater decline in FLI than DPP4 inhibitor use (difference at 1-year measurement, - 3.8 [95% CI - 4.7 to - 3.0]). The advantage of SGLT2 inhibitor use over DPP4 inhibitor use for improvement in FLI was consistent across subgroups. The relationship between SGLT2 inhibitors and amelioration of FLI was comparable between individual SGLT2 inhibitors. CONCLUSIONS: Our analysis using large-scale real-world data demonstrated the potential advantage of SGLT2 inhibitors over DPP4 inhibitors in patients with MAFLD and DM.

Inhibition of intestinal cholesterol absorption might explain cholesterol-lowering effect of telmisartan.

WHAT IS KNOWN AND OBJECTIVE: Telmisartan, an angiotensin II type 1 receptor blocker (ARB), acts as a partial agonist for peroxisome proliferator-activated receptor-γ, and thus improves abnormalities of glucose metabolism and hypertriglyceridaemia in addition to its documented blood pressure-lowering effects. Recently, it has been demonstrated that telmisartan also lowers the levels of total cholesterol and low-density lipoprotein (LDL) cholesterol levels. This study was designed to investigate the mechanism of cholesterol reduction. METHODS: We measured serum levels of cholestanol, a cholesterol absorption marker, and lathosterol, a cholesterol synthesis marker, in 20 patients with both hypercholesterolaemia and hypertension. Ten patients were treated with telmisartan and the remaining 10 with fluvastatin. RESULTS: After 3 months of treatment, total and LDL cholesterol levels decreased in the telmisartan group (P<0.01 for both total and LDL cholesterol levels) and the fluvastatin group (P<0.001 for both total and LDL cholesterol levels). The change in cholestanol level after 3 months of treatment was positively correlated with the levels of total (R=0.72, P<0.05) and LDL cholesterol (R=0.81, P<0.01) in the telmisartan group. The change in lathosterol level was positively correlated with the levels of total (R=0.88, P=0.001) and LDL cholesterol (R=0.89, P=0.001) in the fluvastatin group. WHAT IS NEW AND CONCLUSIONS: Our results suggest that the cholesterol-lowering effect of telmisartan might be caused by inhibition of cholesterol absorption, whereas that of statins is by inhibition of cholesterol synthesis. If confirmed, co-treatment with the two agents may be useful for synergistically lowering cholesterol in hypertensive patients.

Sulfatides are associated with neointimal thickening after vascular injury.

BACKGROUND: Sulfatides are known to be a native ligand of P-selectin. Platelet-leukocyte interaction via the cross-talk between P-selectin and Mac-1 (CD11b/CD18) plays an important role in the mechanism of neointimal thickening after vascular injury such as that seen in post-stent restenosis. However, the roles of sulfatides on restenosis have not been elucidated. METHODS: Serum sulfatide levels, P-selectin expression on the surface of platelets, and activated Mac-1 on the surface of neutrophils were serially measured using both coronary sinus and peripheral blood samples in 21 patients who underwent coronary stent implantation. RESULTS: The trans-cardiac gradient (coronary sinus minus peripheral blood) of the sulfatide levels significantly increased at 15 min (-1.47+/-2.87 to 0.59+/-1.44 nmol/ml, p<0.001), compared to baseline levels. The maximum response of the trans-cardiac gradient of P-selectin expression on the surface of platelets at 15 min after stent implantation (R=0.55, p<0.01), and that of activated Mac-1 on the surface of neutrophils at 48 h (R=0.59, p<0.01), were both positively correlated with that of serum sulfatide levels at 15 min. The angiographic late lumen loss was correlated with the trans-cardiac gradient of sulfatide levels at 15 min (R=0.48, p<0.05), platelet P-selectin expression at 15 min (R=0.42, p<0.05) and activated neutrophil Mac-1 expression at 48 h (R=0.46, p<0.05), but not with values at other sampling points. CONCLUSIONS: Sulfatides may play a physiological role on inflammation in vascular injury and the development of neointimal thickening.

Additional renoprotective effects of azelnidipine combined with angiotensin receptor blockers in patients with diabetic nephropathy.

Azelnidipine has been reported to have antioxidant effects and attenuates tubulointerstitial ischemia. The aim of the present study was to determine whether azelnidipine exerts additional renoprotective effects to angiotensin II receptor blockers (ARBs) in hypertensive patients with diabetic nephropathy and microalbuminuria. 45 hypertensive patients with diabetes mellitus and microalbuminuria who were already being treated with ARBs were enrolled in this study. Azelnidipine was added to the drug treatment of 30 patients (8 mg/day, n = 15, or 16 mg/day, n = 15) whilst the remaining 15 control patients were not treated with azelnidipine. In all patients, urinary 8-hydroxydeoxyguanosine (8-OHdG) levels and urinary liver-type fatty acid-binding protein (L-FABP) levels were significantly correlated (r = 0.587, p = 0.0006). However, urinary albumin excretion (UAE) was not correlated with the levels of urinary 8-OHdG (r = 0.1975, p = 0.2956) or urinary L-FABP (r = 0.2057, p = 0.2759). Azelnidipine significantly reduced UAE, urinary 8-OHdG and urinary L-FABP after 6 (p < 0.05) and 12 months (p < 0.05). Although blood pressure was comparable between the azelnidipine doses of 8 and 16 mg/day, the UAE (p < 0.05 after 12 months), urinary 8-OHdG (p < 0.05 after 6 and 12 months) and urinary L-FABP (p < 0.05 after 6 and 12 months) levels were more significantly reduced in patients receiving the higher dose of 16 mg/day. These data may suggest that the addition of azelnidipine treatment to therapy with ARBs has dose-dependent antioxidant and renoprotective effects beyond blood pressure-lowering effects in hypertensive diabetic nephropathy patients.

Reversible primary hypothyroidism in Japanese patients undergoing maintenance hemodialysis.

BACKGROUND/METHODS: The presence or absence of hypothyroidism was assessed in 152 consecutive Japanese patients with end-stage renal disease on hemodialysis. Eight patients who had undergone treatment for thyroid disease before starting hemodialysis therapy, and 3 patients with amyloidosis due to rheumatoid arthritis were excluded. RESULTS: Of the remaining 141 hemodialysis patients, 14 (9.9%) (9 males and 5 females, aged 69.1 A+/- 8.8 years with a mean duration of hemodialysis of 69 A+/- 51 months) were in a hypothyroid state, defined as a thyroid-stimulating hormone (TSH) level > 5 mU/l. Antithyroid peroxidase antibodies were positive in only 1 of the 14 patients, while antithyroglobulin antibodies were negative in all of these patients. After iodide restriction, the serum TSH level decreased in all the patients from a mean of 16.49 A+/- 22.80 to 4.44 A+/- 3.35 mU/l after 1 month, 4.25 A+/- 2.24 mU/l after 2 months and 3.97 A+/- 2.22 mU/l after 3 months. The 3 months of iodide restriction were also associated with decreases in systolic blood pressure (142 A+/- 19 to 125 A+/- 16 mmHg, p < 0.05), diastolic blood pressure (79 A+/- 13 to 72 A+/- 9 mmHg, p < 0.05) and thyroid gland volume estimated by ultrasonography (13.7 A+/- 6.3 to 11.6 A+/- 5.2 ml, p < 0.05). CONCLUSION: A high prevalence of reversible primary hypothyroidism was found in end-stage renal disease patients on hemodialysis. Retention of excess iodide may be the mechanism responsible for reversible hypothyroidism rather than immunological perturbations. It is, therefore, recommended to attempt iodide restriction before starting l-thyroxine replacement therapy.

Effect of telmisartan on cholesterol levels in patients with hypertension - Saga Telmisartan Aggressive Research (STAR).

Saga Telmisartan Aggressive Research (STAR) is a single-arm, prospective multi-center trial to evaluate the effectiveness of treatment with telmisartan in patients with hypertension. A total of 197 patients with a systolic blood pressure of > or =140 or a diastolic blood pressure of > or =90 mmHg were enrolled in this study, and were prescribed 20 to 80 mg/day of telmisartan for 6 months. In all patients, both systolic and diastolic blood pressures decreased (159+/-20 to 135+/-12 mmHg, p<0.0001, 87+/-12 to 75+/-8 mmHg, p<0.0001, respectively). In addition, total cholesterol (TC) levels decreased from 200+/-40 to 188+/-33 mg/dl (p<0.05). In patients with TC > or =220 mg/dl, the change was more striking (249+/-33 to 204+/-31 mg/dl, p<0.0001). Even in patients receiving statins, TC levels still were decreased (216+/-51 to 190+/-31 mg/dl, p<0.02). In addition, TC levels were also decreased even in patients receiving telmisartan in exchange for other ARBs with TC > or =220 mg/d. Triglyceride (TG) levels were decreased (270+/-199 to 175+/-74 mg/dl, p<0.005) in patients with TG levels > or =150 mg/dl. Fasting blood glucose (FBG) was decreased (158+/-68 to 138+/-60 mg/dl, p<0.05) in patients with FBG > or =110 mg/dl. These results suggest that telmisartan may have favorable effects on lipid and glucose metabolism, in addition to lowering blood pressure. The profound effect of telmisartan to lower cholesterol suggests a potential use in hypertensive patients with dyslipidemia.

Simvastatin decreases IL-6 and IL-8 production in epithelial cells.

Many cardiovascular studies have suggested that 3-hydroxy-3-methylglutaryl co-enzyme A reductase inhibitors (statins) have anti-inflammatory effects independent of cholesterol lowering. As a chronic inflammatory disease, periodontitis shares some mechanisms with atherosclerosis. Since oral epithelial cells participate importantly in periodontal inflammation, we measured simvastatin effects on interleukin-6 and interleukin-8 production by cultured human epithelial cell line (KB cells) in response to interleukin-1alpha. Simvastatin decreased production, an effect reversed by adding mevalonate or geranylgeranyl pyrophosphate, but not farnesyl pyrophosphate. Simvastatin was found to reduce NF-kappaB and AP-1 promoter activity in KB cells. Dominant-negative Rac1 severely inhibited interleukin-1alpha-induced NF-kappaB and AP-1 promoter activity. Our results may indicate an anti-inflammatory effect of simvastatin on human oral epithelial cells, apparently involving Rac1 GTPase inhibition.

Impaired cardiac response to exercise in post-menopausal women: relationship with peripheral vascular function.

Endothelial dysfunction has been demonstrated in post-menopausal women. To assess the relationship between peripheral vascular reserve and cardiac function during exercise in post-menopausal women, 91 subjects, who had no ischaemic findings on myocardial SPECT, were assigned to four groups: pre-menopausal women (n=13), post-menopausal women (n=33), younger men aged < or =50 years (n=10), and older men aged >50 years (n=35). First-pass radionuclide angiography was performed before and during bicycle exercise to calculate ejection fraction (EF) and peripheral vascular resistance (VR). There were no differences in haemodynamic variables among the groups at baseline. The per cent increase in EF=(exercise EF - resting EF)x100/resting EF, and the per cent decrease in VR=(resting VR - exercise VR)x100/resting VR were depressed in the post-menopausal women (0.4+/-2% and 35+/-3%, respectively) compared to the pre-menopausal women (10+/-3% and 47+/-3%, respectively; P<0.05 each). Although the age dependent impairment is thought to cause this depression, neither the per cent increase in EF nor the per cent decrease in VR in the older men was significantly different from that in the younger men. Post-menopausal women exhibited depressed cardiac function during exercise, which may be related to the impairment of peripheral vascular function after menopause.

Association of (-)786T-C mutation of endothelial nitric oxide synthase gene with insulin resistance.

AIMS/HYPOTHESIS: Endothelial derived nitric oxide synthase ( eNOS) gene polymorphisms affect eNOS activity and are associated with abnormal vasomotility and impaired local blood flow. A decrease in local blood flow has been reported to cause insulin resistance. The aim of this study was to examine a possible association of two eNOS polymorphisms, Glu298Asp (G894T) in exon 7 and (-)786T-C mutation with insulin resistance. METHODS: Genotypes of both Glu298Asp and (-)786T-C mutation were examined by the PCR-RFLP method. Plasma nitrate and nitrite concentrations were also measured. RESULTS: The allele frequencies of both polymorphisms showed no considerable differences in 233 non-diabetic subjects and 301 patients with Type II (non-insulin-dependent) diabetes mellitus. Non-diabetic subjects with the (-)786C allele had (p<0.05) higher fasting plasma insulin and homeostasis model assessment of insulin resistance than those with the (-)786T/ (-)786T genotype. Diabetic subjects with (-)786C allele showed higher HbA(1c) than those with the (-)786T/(-)786T genotype. A euglycaemic hyperinsulinemic clamp study done on 71 of the 301 patients showed a lower glucose infusion rate in diabetic patients with the (-)786C allele than those without it. In diabetic patients with the (-)786C allele, plasma nitrate and nitrite concentrations were lower than in subjects without it (p=0.026). No differences were observed between mutant carriers of Glu298Asp and non-carriers among both non-diabetic subjects and Type II diabetic patients. CONCLUSIONS/INTERPRETATION: The (-)786T-C mutation of the eNOS gene is associated with insulin resistance in both Japanese non-diabetic subjects and Type II diabetic patients.

Benidipine, a long-acting Ca channel blocker, limits infarct size via bradykinin- and NO-dependent mechanisms in canine hearts.

Amlodipine increases NO levels in coronary vessels and aorta via bradykinin-dependent mechanisms in vitro. We have previously reported that a long-acting Ca channel blocker, benidipine, increases cardiac NO levels in ischemic canine hearts, suggesting that benidipine may also protect against ischemia and reperfusion injury via bradykinin- and NO-dependent mechanisms. We examined this possibility. In open chest dogs, the left anterior descending coronary artery was perfused with blood through a bypass tube and was occluded for 90 min followed by 6 hours of reperfusion. Infarct size was assessed by TTC staining at 6 hours of reperfusion. When benidipine doses of 50, 100, and 200 ng/kg/min were infused via the bypass tube between 10 min prior to the onset of ischemia and after 60 min of reperfusion, systemic blood pressure did not change significantly. Infarct size decreased with the administration of benidipine (50, 100, and 200 ng/kg/min) when compared to the untreated condition (24.8+/-2.5, 17.3+/-3.1, and 16.5+/-2.0 vs. 43.4+/-5.6%, respectively) associated with the increased release of NO and bradykinin in the coronary venous blood upon reperfusion. Myeloperoxidase activity of the myocardium increased after 6 hours of reperfusion, which was attenuated by benidipine. The limitation of infarct size and the increase in myeloperoxidase activity were completely blunted by either L-NAME or HOE140. There were no significant differences in collateral blood flow assessed by the microsphere method after 45 min of ischemia for any of the groups. Thus, we conclude that the Ca channel blocker, benidipine, limits infarct size via bradykinin- and NO-dependent mechanisms.

Statins as antioxidant therapy for preventing cardiac myocyte hypertrophy.

Cardiac hypertrophy is a major cause of morbidity and mortality worldwide. The hypertrophic process is mediated, in part, by small G proteins of the Rho family. We hypothesized that statins, inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, inhibit cardiac hypertrophy by blocking Rho isoprenylation. We treated neonatal rat cardiac myocytes with angiotensin II (AngII) with and without simvastatin (Sim) and found that Sim decreased AngII-induced protein content, [3H] leucine uptake, and atrial natriuretic factor (ANF) promoter activity. These effects were associated with decreases in cell size, membrane Rho activity, superoxide anion (O2*-) production, and intracellular oxidation, and were reversed with L-mevalonate or geranylgeranylpyrophosphate, but not with farnesylpyrophosphate or cholesterol. Treatments with the Rho inhibitor C3 exotoxin and with cell-permeable superoxide dismutase also decreased AngII-induced O2*- production and myocyte hypertrophy. Overexpression of the dominant-negative Rho mutant N17Rac1 completely inhibited AngII-induced intracellular oxidation and ANF promoter activity, while N19RhoA partially inhibited it, and N17Cdc42 had no effect. Indeed, Sim inhibited cardiac hypertrophy and decreased myocardial Rac1 activity and O2*- production in rats treated with AngII infusion or subjected to transaortic constriction. These findings suggest that statins prevent the development of cardiac hypertrophy through an antioxidant mechanism involving inhibition of Rac1.

Nifedipine limits infarct size via NO-dependent mechanisms in dogs.

OBJECTIVES: Amlodipine increases NO levels in coronary vessels and aorta via bradykinin-dependent mechanisms in vitro. We have previously reported that nifedipine increases cardiac NO levels in the ischemic canine hearts, suggesting that nifedipine may also have protective effects against ischemia and reperfusion injury, because the enhancement of NO production limits infarct size. We tested whether nifedipine limits infarct size via NO-dependent mechanisms. METHODS: In open chest dogs, the left anterior descending coronary artery was perfused with blood through a bypass tube and occluded for 90 min followed by 6 hours of reperfusion. Infarct size was assessed at 6 hours of reperfusion. Nifedipine of 3 or 6 microg/kg/min was infused into the bypass tube between 10 min prior to the onset of ischemia and 60 min of reperfusion. RESULTS: Neither systemic blood pressure nor heart rate changed during infusion of nifedipine. Infarct size was reduced by the administration of nifedipine (3 or 6 microg/kg/min) compared with the untreated condition (25.6+/-2.6 and 19.1+/-3.5 vs. 43.4+/-5.6%, respectively), which was completely blunted by L-NAME (45.0+/-3.6 and 45.4+/-4.2 vs. 47.9+/-3.9% in the nifedipine (3 or 6 microg/kg/min) with L-NAME groups vs. the L-NAME group). Myeloperoxidase activity of the myocardium increased after 6 hours of reperfusion, which was attenuated by nifedipine. The limitation of infarct size and the attenuation in myeloperoxidase actiivity were completely blunted by L-NAME. There were no significant differences in collateral blood flow at 45 min of ischemia between each group. CONCLUSIONS: We conclude that the Ca channel blocker, nifedipine, limits infarct size via NO-dependent mechanisms.

Differential subcellular actions of ACE inhibitors and AT(1) receptor antagonists on cardiac remodeling induced by chronic inhibition of NO synthesis in rats.

Chronic inhibition of NO synthesis induces cardiac hypertrophy independent of systemic blood pressure (SBP) by increasing protein synthesis in vivo. We examined whether ACE inhibitors (ACEIs) enalapril and temocapril and angiotensin II type-I receptor antagonists (angiotensin receptor blockers [ARBs]) losartan and CS-866 can block cardiac hypertrophy and whether changes in activation of 70-kDa S6 kinase (p70S6K) or extracellular signal-regulated protein kinase (ERK) are involved. The following 13 groups were studied: untreated Wistar-Kyoto rats and rats treated with NO synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME), D-NAME (the inactive isomer of L-NAME), L-NAME plus hydralazine, L-NAME plus enalapril (3 mg. kg(-1). d(-1)) or temocapril (1 or 10 mg. kg(-1). d(-1)), L-NAME plus losartan (10 mg. kg(-1). d(-1)) or CS-866 (1 or 10 mg. kg(-1). d(-1)), L-NAME plus temocapril-CS866 in combination (1 or 10 mg. kg(-1). d(-1)), and L-NAME plus rapamycin (0.5 mg. kg(-1). d(-1)). After 8 weeks of each experiment, ratios of coronary wall to lumen (wall/lumen) and left ventricular weight to body weight (LVW/BW) were quantified. L-NAME increased SBP, wall/lumen, and LVW/BW compared with that of control. ACEIs, ARBs, and hydralazine equally canceled the increase in SBP induced by L-NAME. However, ACEIs and ARBs equally (but not hydralazine) attenuated increase in wall/lumen and LVW/BW induced by L-NAME. The L-NAME group showed both p70S6K and ERK activation in myocardium (2.2-fold and 1.8-fold versus control, respectively). ACEIs inactivated p70S6K and ARBs inactivated ERK in myocardium, but hydralazine did not change activation of either kinase. Thus, ACEIs and ARBs modulate different intracellular signaling pathways, inhibiting p70S6K or ERK, respectively, to elicit equal reduction of cardiac hypertrophy induced by chronic inhibition of NO synthesis in vivo.

Role of cellular acidosis in production of nitric oxide in canine ischemic myocardium.

We tested the hypothesis that cellular acidosis modulates the production of nitric oxide (NO) in ischemic hearts. In canine hearts, we decreased coronary blood flow (CBF) to one third of the control by reduction of coronary perfusion pressure (105+/-3 to 41+/-5 mmHg), and thereafter we maintained CBF constant (89.8+/-1.6 to 30.0+/-0.5 ml/100 g/min) with an intracoronary administration of either saline, atropine, rauwolscine, HOE140, 8-sulfophenyltheophylline (8SPT), NaHCO3, or HOE642 (the inhibitor of Na+/H+ exchange). The cardiac NO levels defined as the differences of the nitrate and nitrite levels between coronary venous and arterial blood increased in the saline administration (2.9+/-0.2 to 12.7+/-1.7 micromol/l), and the extents of increases were identical in the condition of either saline, atropine, rauwolscine, HOE140 or 8SPT administration. In the condition with either NaHCO3 or HOE642, the increases in the cardiac NO levels were blunted (4.5+/-0.7 and 4.8+/-0.4 micromol/l, respectively). Cyclic GMP content of epicardial coronary artery in the ischemic area increased, which was also attenuated by either NaHCO3 or HOE642. We confirmed the acidosis-induced NO production in a more severe ischemic myocardium, and also showed that cellular acidosis produced by infusion of HCl increased NO production in non-ischemic myocardium. We conclude that cellular acidosis and subsequent activation of Na+/H+ exchanges modulate production of endogenous NO in canine ischemic myocardium.

Cardioprotective effect afforded by transient exposure to phosphodiesterase III inhibitors: the role of protein kinase A and p38 mitogen-activated protein kinase.

BACKGROUND: Phosphodiesterase III inhibitors (PDEIII-Is) improve the hemodynamic status of heart failure via inotropic/vasodilatory effects attributable to the increase in intracellular cAMP level. Direct cardioprotection by PDEIII-Is and its underlying mechanisms, however, have not been identified. We tested the infarct size-limiting effect of PDEIII-Is and the roles of cAMP, protein kinase (PK) A, PKC, and mitogen-activated protein kinase (MAPK) families in open-chest dogs. Methods and Results-- Milrinone, olprinone (PDEIII-Is), or dibutyryl-cAMP (db-cAMP) was injected intravenously 30 minutes before 90-minute ischemia, followed by 6 hours of reperfusion. Olprinone was also examined with an intracoronary cotreatment with a PKA inhibitor (H89), a PKC inhibitor (GF109203X), an extracellular signal-regulated kinase kinase (MEK) inhibitor (PD98059), or a p38 MAPK inhibitor (SB203580) throughout the preischemic period. Either PDEIII-Is or db-cAMP caused substantial hemodynamic changes, which returned to control levels in 30 minutes. Collateral flow and percent risk area were identical for all groups. Both PDEIII-Is and db-cAMP increased myocardial p38 MAPK activity during the preischemic period, which was blocked by H89, but not by GF109203X. Both PDEIII-Is and db-cAMP reduced infarct size (19.1+/-4.1%, 17.5+/-3.3%, and 20.3+/-4.8%, respectively, versus 36.1+/-6.2% control, P<0.05 each). Furthermore, the effect of olprinone was blunted by either H89 (35.5+/-6.4%) or SB203580 (32.6+/-5.9%), but not by GF109203X or PD98059. H89, GF109203X, PD98059, or SB203580 alone did not influence infarct size. CONCLUSIONS: Pretreatment with PDEIII-Is has cardioprotective effects via cAMP-, PKA-, and p38 MAPK-dependent but PKC-independent mechanisms in canine hearts.

Effects of bezafibrate and simvastatin on plasma lipoproteins in hypercholesterolemia resistant to hormone replacement therapy.

OBJECTIVES: Estrogen replacement therapy has favorable effects on serum lipoprotein levels in postmenopausal women with hypercholesterolemia. However, there are some patients who fail to respond to hormone replacement therapy (HRT) to lower the serum cholesterol level. In these cases, a conventional lipid-lowering therapy will be applied in addition to HRT, while the effects of these drugs are not well understood. In this study, we studied the effects of simvastatin and bezafibrate administered in addition to HRT. METHODS: Patients who were hypercholesterolemic even after HRT were randomly assigned to three treatment groups: HRT only (control group, n=10), HRT+simvastatin (10 mg/day, n=10), or HRT+bezafibrate (400 mg/day, n=10). Serum lipids and lipoprotein levels were measured throughout 12 weeks. RESULTS: The serum triglyceride levels were decreased by 24+/-28 and 38+/-13% in the HRT+simvastatin and HRT+bezafibrate groups, respectively. HRT+simvastatin decreased the total cholesterol (21+/-10%) and low-density lipoprotein cholesterol (28+/-12%) levels without affecting the high-density lipoprotein cholesterol (HDL-C) level, while HRT+bezafibrate increased the HDL-C level (12+/-11%). CONCLUSIONS: Treatment with simvastatin or bezafibrate in addition to HRT should be considered in cases of postmenopausal hypercholesterolemia in which HRT alone fails to lower the serum lipoprotein levels.

Activation of Galpha s mediates induction of tissue-type plasminogen activator gene transcription by epoxyeicosatrienoic acids.

The epoxyeicosatrienoic acids (EETs) are products of cytochrome P450 (CYP) epoxygenases that have vasodilatory and anti-inflammatory properties. Here we report that EETs have additional fibrinolytic properties. In vascular endothelial cells, physiological concentrations of EETs, particularly 11,12-EET, or overexpression of the endothelial epoxygenase, CYP2J2, increased tissue plasminogen activator (t-PA) expression by 2.5-fold without affecting plasminogen activator inhibitor-1 expression. This increase in t-PA expression correlated with a 4-fold induction in t-PA gene transcription and a 3-fold increase in t-PA fibrinolytic activity and was blocked by the CYP inhibitor, SKF525A, but not by the calcium-activated potassium channel blocker, charybdotoxin, indicating a mechanism that does not involve endothelial cell hyperpolarization. The t-PA promoter is cAMP-responsive, and induction of t-PA gene transcription by EETs correlated with increases in intracellular cAMP levels and, functionally, with cAMP-driven promoter activity. To determine whether increases in intracellular cAMP levels were due to modulation of guanine nucleotide-binding proteins, we assessed the effects of EETs on Galpha(s) and Galpha(i2). Treatment with EETs increased Galpha(s), but not Galpha(i2), GTP-binding activity by 3.5-fold. These findings indicate that EETs possess fibrinolytic properties through the induction of t-PA and suggest that endothelial CYP2J2 may play an important role in regulating vascular hemostasis.

Role of phasic dynamism of p38 mitogen-activated protein kinase activation in ischemic preconditioning of the canine heart.

Although ischemic stress, including ischemic preconditioning (IP), activates p38 mitogen-activated protein kinase (MAPK), the relationship between p38 MAPK activation and the underlying cellular mechanisms of cardioprotection by IP is not verified in vivo. We examined the effects of the selective p38 MAPK inhibition on the cardioprotective effect of IP in the open-chest dogs. The coronary artery was occluded 4 times for 5 minutes, separated by 5 minutes of reperfusion (IP) followed by 90 minutes of occlusion and 6 hours of reperfusion. We infused SB203580 into the coronary artery during IP and 1 hour of reperfusion, during IP alone, and during sustained ischemia in the IP group. p38 MAPK activity markedly increased during IP but did not additionally increase at the onset of ischemia and was even attenuated at 15 minutes of sustained ischemia, and heat-shock protein (HSP) 27 was phosphorylated and translocated from cytosol to myofibril or nucleus without affecting total protein level at the onset of ischemia compared with the control group. SB203580 treatment (1 micromol/L) only during IP blunted the infarct size limitation by IP (37.3+/-6.3% versus 7.4+/-2.1% in the IP group, P:<0.01) and attenuated either phosphorylation or translocation of HSP27 during IP. Although the SB203580 treatment throughout the preischemic and postischemic periods had no significant effect on infarct size (33.3+/-9.4%) in this model, treatment with SB203580 only during ischemia partially mimicked the infarct size limitation by IP (26.8+/-3.5%). Thus, transient p38 MAPK activation during ischemic preconditioning mainly mediates the cardioprotection followed by HSP27 phosphorylation and translocation in vivo in the canine heart.

Role of mitochondrial and sarcolemmal K(ATP) channels in ischemic preconditioning of the canine heart.

We tested whether mitochondrial or sarcolemmal ATP-sensitive K(+) (K(ATP)) channels play a key role in ischemic preconditioning (IP) in canine hearts. In open-chest beagle dogs, the left anterior descending artery was occluded four times for 5 min each with 5-min intervals of reperfusion (IP), occluded for 90 min, and reperfused for 6 h. IP as well as cromakalim and nicorandil (nonspecific K(ATP) channel openers) markedly limited infarct size (6.3 +/- 1.2, 8.9 +/- 1.9, and 7.2 +/- 1.6%, respectively) compared with the control group (40.9 +/- 4.1%). A selective mitochondrial K(ATP) channel blocker, 5-hydroxydecanoate, partially blunted the limitation of infarct size in the animals subjected to IP and those treated with cromakalim and nicorandil (21.6 +/- 3.8, 25.1 +/- 4.6, and 19.8 +/- 5.2%, respectively). A nonspecific K(ATP) channel blocker, glibenclamide, completely abolished the effect of IP (38.5 +/- 6.2%). Intracoronary or intravenous administration of a mitochondria-selective K(ATP) channel opener, diazoxide, at >100 micromol/l could only partially decrease infarct size (19.5 +/- 4.3 and 20.1 +/- 4.4%, respectively). In conclusion, mitochondrial and sarcolemmal K(ATP) channels independently play an important role in the limitation of infarct size by IP in the canine heart.

Protein tyrosine kinase is not involved in the infarct size-limiting effect of ischemic preconditioning in canine hearts.

Protein kinase C (PKC) plays an important role in ischemic preconditioning (IP). Because (1) tyrosine kinase is located at the downstream of PKC for IP in the rabbit hearts and (2) we have reported that ecto-5'-nucleotidase is the substrate for PKC and plays a crucial role for the infarct size-limiting effect, we tested whether tyrosine kinase activation contributes to either activation of ecto-5'-nucleotidase or the infarct size-limiting effect of the early phase of IP in the canine heart. In dogs, the IP procedure (4 cycles of 5-minute occlusion of coronary artery) and exposure to 12, 13-phorbol myristate acetate (PMA) each activated myocardial ecto-5'-nucleotidase and Lck tyrosine kinase. Genistein (10, 30, and 100 microg. kg(-)(1). min(-)(1) IC), an inhibitor of tyrosine kinase, attenuated the activation of Lck tyrosine kinase but did not attenuate the activation of ecto-5'-nucleotidase due to either IP or PMA. In the other canine hearts, IP attenuated infarct size (49+/-5 versus 11+/-3 or 16+/-3%, P<0.01) due to 90 minutes of coronary occlusion followed by 6 hours of reperfusion, which was not blunted by 3 or 2 (30 and 100 microg. kg(-)(1). min(-)(1)) doses of genistein (infarct sizes, 15+/-4, 13+/-4, and 13+/-3%, respectively, and 17+/-3 and 15+/-4%, respectively) or lavendustin A. Tyrosine kinase does not activate ecto-5'-nucleotidase or trigger the infarct size-limiting effect of the early phase of IP in canine hearts.