Relationship between Insulin Resistance and the Renin-Angiotensin System: Analysis for Patients with Essential and Renovascular Hypertension

Combined maternal and postnatal high-fat diet leads to metabolic syndrome and is effectively reversed by resveratrol: a multiple-organ study

This study aimed to study the impact of a combination of maternal and post-weaning high-fat diets and whether resveratrol was beneficial. Sprague-Dawley dams were fed either chow or a high-fat diet, before mating, during pregnancy, and into lactation. At weaning, their offspring were randomly fed chow or a high-fat diet. Four experimental groups were generated: CC (maternal/postnatal chow diet), HC (maternal high-fat/postnatal chow diet), CH (maternal chow/postnatal high-fat diet), and HH (maternal/postnatal high-fat diet). A fifth group consisted of HH plus resveratrol. The 4 month-old offspring of HH group had higher body weight, higher levels of plasma triglycerides, leptin, angiotensin I and angiotensin II and abnormal intraperitoneal glucose tolerance test results, which fulfilled the features of metabolic syndrome. The dysregulation of the renin-angiotensin system was seen in multiple organs. Sirtuin 1 expression/abundance was reduced by a maternal/postnatal high-fat diet, in all the organs examined. Resveratrol ameliorated most of the features of metabolic syndrome and molecular alterations. The administration of a high-fat diet in both periods showed interactive metabolic effects in the plasma and many organs. Our results suggest that a maternal high-fat diet sensitizes offspring to the adverse effects of subsequent high-fat intake on multiple organs.

Antihypertensive Drugs and Diabetic Retinopathy in Patients with Type 2 Diabetes

OBJECTIVE

To evaluate the association between the development of sight-threatening diabetic retinopathy (STDR) and antihypertensive drugs (AHDs) use among type 2 diabetic patients with concomitant hypertension.

METHODS

Type 2 diabetic patients aged 20-100 years who had at least one prescription for AHDs between 2000 and 2011 were identified from the Longitudinal Health Insurance Database (LHID) 2005. The incidence rates of STDR were followed and Cox proportional hazard models were used to analyze the risk associated with AHDs.

RESULTS

Users of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) were associated with a significantly higher risk than users of calcium channel blockers (CCBs), independent of baseline characteristics. After adjusting for time-varying use of concomitant medications for propensity score-matched or -unmatched cohorts, the results showed that patients receiving ACEIs/ARBs and CCBs were associated with a significantly greater risk compared with β-blocker users.

CONCLUSIONS

Our study did not support a superiority of ACEIs/ARBs and CCBs over β-blockers for lowering the progression of diabetic retinopathy.

The influence of long term hydrochlorothiazide administration on the relationship between renin-angiotensin-aldosterone system activity and plasma glucose in patients with hypertension

Objective. To observe the relationship between changes in renin-angiotensin-aldosterone system (RAAS) activity and blood plasma glucose after administration of hydrochlorothiazide (HCTZ) for one year in patients with hypertension. Methods. 108 hypertensive patients were given 12.5 mg HCTZ per day for one year. RAAS activity, plasma glucose levels, and other biochemical parameters, as well as plasma oxidized low density lipoprotein (oxLDL) levels, were measured and analyzed at baseline, six weeks, and one year after treatment. Results. After one year of treatment, the reduction in plasma glucose observed between the elevated plasma renin activity (PRA) group (−0.26 ± 0.26 mmol/L) and the nonelevated PRA group (−1.36 ± 0.23 mmol/L) was statistically significant (P < 0.05). The decrease of plasma glucose in the elevated Ang II group (−0.17 ± 0.18 mmol/L) compared to the nonelevated Ang II group (−1.07 ± 0.21 mmol/L) was statistically significant (P < 0.05). The proportion of patients with elevated plasma glucose in the elevated Ang II group (40.5%) was significantly higher than those in the nonelevated Ang II group (16.3%) (P < 0.05). The relative oxLDL level was not affected by the treatment. Conclusions. Changes in RAAS activity were correlated with changes in plasma glucose levels after one year of HCTZ therapy.

Is insulin resistance a risk factor for the progression of chronic kidney disease?

BACKGROUND

The aim of this research was to establish whether there is a link between insulin resistance (IR) and glomerular filtration rate (GFR), and assess whether insulin-resistant subjects experience a more rapid deterioration in GFR.

METHODS

We enrolled 73 non-diabetic chronic kidney disease (CKD) stage 2-4 patients. All blood samples were taken after 10 h of overnight fasting. Fasting blood glucose (FBG), creatinine, uric acid, albumin, cholesterol, triglyceride, insulin, HbA1c, high-sensitivity C-reactive protein (hs-CRP) and intact parathyroid hormone (iPTH) levels as well as proteinuria were analyzed. Patients were followed up for a mean of 30 (24-35) months and renal and metabolic parameters were compared in conjunction with a homeostasis model assessment of IR (HOMA-IR) between the entry and the end of the study period. CKD progression was assessed by recording renal endpoints, which included end-stage renal disease, requiring renal replacement therapy, or overall mortality.

RESULTS

The study patients were divided into group 1 (n = 36), without IR, and group 2 (n = 37), with IR. Group 2 patients had a higher FBG (p = 0.003) and insulin level (p = 0.001) compared to group 1. The baseline and end of study systolic (p = 0.007) and diastolic (p = 0.001) blood pressures were decreased in group 1. In group 2, FBG (p = 0.008), HbA1c (p = 0.009), systolic (p = 0.024) and diastolic (p = 0.001) blood pressures and CRP (p = 0.047) were decreased. In group 2, 8 patients reached renal endpoints while in group 1, 9 patients reached study endpoints. HOMA-IR was not significantly higher among 17 patients who reached the renal endpoint than among the 56 who did not. At baseline, those patients who reached the renal endpoint showed lower GFR (p = 0.001), higher iPTH (p = 0.004) and hs-CRP (p = 0.002) levels.

CONCLUSION

There was no significant difference in GFR at the end of the study between patients who had or did not have IR. Furthermore, HOMA-IR was not significantly different in patients with or without renal endpoints.

Time to achieve blood pressure goal with a combination versus a conventional monotherapy approach in hypertensive patients with metabolic syndrome

The time to achieve a blood pressure (BP) goal < or =130/85 mmHg with a combination versus a conventional monotherapy approach was evaluated in 308 hypertensive patients with metabolic syndrome. They were randomized to valsartan (V) 8 mg/amlodipine (A) 5 mg combination or to V 160 mg monotherapy for 12 weeks and every 2 weeks, there was a titration in nonresponder patients: in the combination group V/A was progressively increased to V 160/A 5 mg; V160/A 7.5 mg; V160/A 10 mg; V 240/A 10 mg, and V 320/A 10 mg. In the monotherapy group, the regimen was progressively modified as following: V 240 mg; V 320 mg; V 320/A 5 mg; V 320/A 7.5 mg, and V 320/A 10 mg. The mean time to achieve the BP goal was shorter in patients randomized to combination therapy compared to those randomized to conventional monotherapy (4.7 +/- 2.7 weeks vs. 7.1 +/- 3.9 weeks, respectively, p < 0.001). The percentage of patients who achieved target BP in the combination approach group statistically exceeded that of the monotherapy treated one already after 2 weeks of treatment (30.5 vs. 14.9%, p < 0.01) and again after 4, 6, 8, and 10 weeks of treatment. Only at 12 weeks the percentage of normalized patients was similar in the two treatment groups (78.8% vs. 75.3%, ns). These results suggest that initial therapy with a V/A combination approach may be more quickly effective than a conventional sequential monotherapy approach in achieving target BP in hypertensive patients with metabolic syndrome.