Increment in Dietary Potassium Predicts Weight Loss in the Treatment of the Metabolic Syndrome.

BACKGROUND: In the treatment of obesity/metabolic syndrome, dietary measures traditionally focus on reducing carbohydrate/fat-related caloric intake. The possibility that changes in potassium consumption may be related to the achieved weight loss has not been previously explored. METHODS: Sixty-eight participants, with a mean age of 51.6 ± 11.0 years (F/M-30/38), who fulfilled the ATPIII criteria for the metabolic syndrome (MS) were enrolled into a 1-year intensive multidisciplinary program. Nutritional recommendation consisted of a moderate low calorie/high protein Mediterranean diet. Baseline assessment included clinical and biochemical profiling, and body composition. Nutritional components were registered over 7 days before and at the end of 1 year of treatment. RESULTS: Mean baseline body mass index (BMI) was 35 ± 4 kg/m², which declined by 9.4 ± 0.1% after one year of combined intervention. Linear stepwise regression analysis revealed that 45% of the predicted variance of the % decline in BMI was related to increased consumption of dietary potassium (ß = -0.865) and caproic acid (ß = -0.423) and reduction in the consumption of dietary vitamin B6 (ß = 0.542), calcium (ß = 0.335), total carbohydrates (ß = 0.239) and total caloric intake (ß = 0.238; p < 0.001). Notably, the strongest correlate of the decline in BMI was the increase in dietary potassium intake (ß = -0.865). Subjects whose achieved decrease in BMI was above the average (n = 30) increased potassium intake by 25% as compared to an increase in dietary potassium intake of only 3% by those whose decline in BMI was below the average (n = 36; p < 0.05). The change in dietary potassium was related to the percent increase in dietary protein (r = 0.433; p < 0.001). CONCLUSION: An increase in dietary potassium consumption is a previously unrecognized predictor of the achieved reduction in BMI in a weight-loss-oriented multidisciplinary intervention in obesity/MS. Prospective trials are underway to confirm this post-hoc finding.

Arterial properties in acromegaly: relation to disease activity and associated cardiovascular risk factors.

PURPOSE: Acromegaly is associated with increased cardiovascular morbidity and mortality when inadequately treated, which may be secondary to associated comorbidities or to direct IGF-1 effects on the cardiovascular system. By using a control group carefully matched for traditional cardiovascular risk factors, we aimed to assess the direct contribution of disease activity and IGF-1 levels to arterial damage as assessed by measurements of arterial stiffness and endothelial function. METHODS: Twenty-nine subjects with acromegaly (11 males, 52 ± 14 year; 15 active acromegaly) and 24 matched controls underwent evaluation of large and small artery compliance using applanation tonometry, pulse wave velocity (PWV), augmentation index (Alx), carotid ultrasonography intima-media thickness, (IMT) and flow-mediated dilatation (FMD). RESULTS: IGF-1 expressed as times the upper limit of the normal range (x ULN) was 2.2 ± 1.1 in patients with active disease versus 0.7 ± 0.2 in patients in remission. Irrespective of disease activity, FMD was lower in patients with acromegaly than in control subjects, (3.4 ± 2.7 % in active acromegaly, 4.4 ± 3.3 % in controlled acromegaly and 7.5 ± 3.8 % in controls; p = 0.004). There were no significant differences in PWV, Alx, and IMT between groups. A positive correlation was found between IGF-1× ULN and IMT (r = 0.4; P = 0.02). Asymmetric dimethylarginine (ADMA), a novel cardiovascular risk factor, was positively correlated to arterial stiffness (r = 0.46; p = 0.017) and negatively with small vessel compliance (r = -0.44, p = 0.02). CONCLUSIONS: Patients with acromegaly have significantly impaired endothelial function as assessed by FMD, but other tested vascular parameters were similar to a control group that was adequately matched for cardiovascular risk factors.

Multidisciplinary Treatment of the Metabolic Syndrome Lowers Blood Pressure Variability Independent of Blood Pressure Control.

Blood pressure (BP) variability (BPV) contributes to target organ damage independent of BP. The authors examined the effect of a 1-year multidisciplinary intervention on BPV in patients with the metabolic syndrome (MetS) as defined by criteria from the Third Report of the Adult Treatment Panel. Forty-four nondiabetic patients underwent clinical and biochemical profiling, 24-hour ambulatory BP monitoring (ABPM), body composition, carotid intima-media thickness, and carotid-femoral pulse wave velocity (PWV). The intervention targeted all MetS components. BPV was assessed by the standard deviation of daytime systolic BP derived from ABPM. Patients with low and high BPV (lower or higher than the median daytime standard deviation of 11.6 mm Hg) did not differ in regards to systolic and diastolic BP, age, fasting glucose, glycated hemoglobin, and body mass index, but the high-variability group had higher values of low-density lipoprotein and leg fat. The 1-year intervention resulted in weight reduction but not BP-lowering. BPV declined in the high-variability group in association with lowering of PWV, C-reactive protein, glycated hemoglobin, alanine aminotransferase, asymmetric dimethylarginine, and increased high-density lipoprotein cholesterol. A multidisciplinary intervention independent of BP-lowering normalized BPV, lowered PWV, and enhanced metabolic control.

The Proatherogenic Effect of Chronic Nitric Oxide Synthesis Inhibition in ApoE-Null Mice Is Dependent on the Presence of PPAR α.

Inhibition of endothelial nitric oxide synthase (eNOS) accelerates atherosclerosis in ApoE-null mice by impairing the balance between angiotensin II (AII) and NO. Our previous data suggested a role for PPAR α in the deleterious effect of the renin-angiotensin system (RAS). We tested the hypothesis that ApoE-null mice lacking PPAR α (DKO mice) would be resistant to the proatherogenic effect of NOS inhibition. DKO mice fed a Western diet were immune to the 23% worsening in aortic sinus plaque area seen in the ApoE-null animals under 12 weeks of NOS inhibition with a subpressor dose of L-NAME, P = 0.002. This was accompanied by a doubling of reactive oxygen species (ROS-) generating aortic NADPH oxidase activity (a target of AII, which paralleled Nox1 expression) and by a 10-fold excess of the proatherogenic iNOS, P < 0.01. L-NAME also caused a doubling of aortic renin and angiotensinogen mRNA level in the ApoE-null mice but not in the DKO, and it upregulated eNOS in the DKO mice only. These data suggest that, in the ApoE-null mouse, PPAR α contributes to the proatherogenic effect of unopposed RAS/AII action induced by L-NAME, an effect which is associated with Nox1 and iNOS induction, and is independent of blood pressure and serum lipids.

Low-dose calcitriol decreases aortic renin, blood pressure, and atherosclerosis in apoe-null mice.

AIMS: To determine whether low-dose calcitriol attenuates atherosclerosis in apoE-null mice and, if so, through which predominant mechanism. METHODS: Starting at the age of 6 weeks, mice received intraperitoneal injections of either 0.25 ng/g body weight of calcitriol or the vehicle, every other day for 8 weeks. RESULTS: Calcitriol treatment resulted in 35% reduction of atherosclerosis at the aortic sinus, and in a significant decrease in blood pressure. These effects were possibly mediated by downregulation of the renin-angiotensin system (RAS), as there was a 64% decrease in the aortic level of renin mRNA. None of the other components of the RAS or the prorenin receptor were affected by treatment. Low-dose calcitriol treatment did not modify the plasma level of monocyte chemoattractant protein-1, interferon γ, interleukin-4 and interleukin-10, which were similar in control and treated mice. Likewise, there was no difference in the percentage of splenic Foxp3+ regulatory T cells. Calcitriol treatment resulted in an unfavorable metabolic profile (glucose and lipids), as determined after a limited fast, a difference that disappeared after food was withheld for a longer time. CONCLUSIONS: At a relatively low dosage, calcitriol attenuates the development of atherosclerosis in apoE-null mice, most probably by down regulation of RAS, and not through immunomodulation; however, even at this low dose, calcitriol appears to elevate calcium and to have potentially adverse metabolic effects. Exploring the potential antiatherogenic effects of non-calcemic and safer analogues is therefore warranted.

Inhibition of intimal thickening in the rat carotid artery injury model by a nontoxic Ras inhibitor.

BACKGROUND: Neointimal formation with and without previous vascular injury is common after balloon dilation and in transplant arteriosclerosis. It involves proliferation and migration of medial smooth muscle cells and inflammation, processes that are regulated by Ras proteins and their down-stream effectors. Farnesylthiosalicylate (FTS) is a Ras inhibitor that interferes with Ras membrane anchorage and affects Ras proteins in their active state. In the present study, we tested the hypothesis that systemic administration of FTS will suppress intimal thickening in the rat carotid injury model. METHODS AND RESULTS: The effects of FTS on rat vascular smooth muscle cells (VSMC) and splenocytes proliferation were evaluated in vitro. The in vivo effects of FTS on the neointima of balloon-injured male Wistar rats, treated daily for 2 weeks with FTS (5 mg/kg weight, intraperitoneally) were evaluated by determination of Ras, Ras-GTP, and active ERK levels (3 days after injury), and by quantitative determination of the extent of intimal thickening and immunohistochemistry for Ras, iNOS, NFkB, and Ki-67 (2 weeks after injury). FTS inhibited VSMC and splenocyte proliferation as well as interferon-gamma secretion by splenocytes in a dose-dependent manner. Compared with controls, FTS treatment resulted in a strong decrease in Ras-GTP and active ERK, and it significantly reduced intimal thickening after the injury. Ras expression appeared predominantly at areas of neointima regardless of the treatment group. NFkB and iNOS-positive cell numbers were reduced in sections of FTS treated rats. CONCLUSIONS: FTS appears to act as a potent inhibitor of intimal thickening in a model of experimental arterial injury.