Angiotensin blockade in diabetic patients decreases insulin resistance-associated low-grade inflammation

Effects of acarbose and metformin on the inflammatory state in newly diagnosed type 2 diabetes patients: a one-year randomized clinical study

OBJECTIVE

This study aimed to investigate the changes in inflammatory biomarkers between newly diagnosed type 2 diabetes (T2DM) patients under one-year acarbose treatments and those under metformin managements.

METHODS

Seventy patients with newly diagnosed T2DM and 32 volunteers with normal glucose tolerance (normal controls, NCs) were enrolled. Seventy patients with T2DM were randomly assigned to two subgroups and treated with acarbose (n=34) or metformin (n=36) for 1 year. Blood glucose, insulin, glycosylated hemoglobin (A1C), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and inflammatory biomarker levels (interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-2 (IL-2), and ferritin) were detected at 0, 6 and 12 months.

RESULTS

After adjusting for sex, the waist-to-hip ratio (WHR) and body mass index (BMI), higher fasting plasma glucose (FPG), standard meal test 1/2 hr and 2 hr glucose, TG, TC, LDL-C, IL-6, TNF-α, IL-2 and ferritin levels were observed in T2DM group than in NCs (P<0.05). After 6 months of treatment, TNF-α levels were significantly decreased in both subgroups, and IL-6 and ferritin levels were significantly decreased after 12 months (P<0.05). However, no significant differences in the IL-6, TNF-α and ferritin levels were observed between the two subgroups. Moreover, significantly higher IL-6 and TNF-α levels were detected in the T2DM group than in NCs after 12 months of treatment (P<0.05).

CONCLUSION

Patients with newly diagnosed T2DM exhibited a marked chronic inflammatory state characterized by increased IL-6, TNF-α, IL-1β, IL-2 and ferritin levels. After 1 year of treatment with acarbose or metformin, IL-6, TNF-α, IL-1β and ferritin levels were significantly decreased compared with the baseline. The anti-inflammatory effects of acarbose and metformin were comparable and required a long-term treatment (1 year), but the characteristics were different. Further investigations are needed to determine whether this effect was independent of the hypoglycemic effects.

Complete blood count-derived inflammatory markers in adolescents with primary arterial hypertension: a preliminary report

Aim of the study

The aim of our study was to evaluate selected inflammatory markers in children with untreated primary hypertension and to establish the relation between inflammatory markers and 24-hour ambulatory blood pressure monitoring (ABPM) and clinical and biochemical parameters.

Material and methods

In 54 children (15.12 ±2.02 years) with untreated primary hypertension, with excluded overt inflammation, we evaluated: neutrophils (NEU; 1000/μl), lymphocytes (LYM; 1000/μl), platelets (PLT; 1000/μl), mean platelet volume (MPV; fl), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), ABPM (OSCAR 2 SUNTECH), and selected clinical and biochemical parameters. The control group consisted of 20 healthy children (15.55 ±2.27 years).

Results

Children with primary hypertension had (p < 0.01) higher 24-hour systolic, diastolic and mean blood pressure, systolic and diastolic blood pressure loads, and pulse pressure. Hypertensive children did not differ in inflammatory indicators (NEU, LYM, PLT, MPV, NLR, PLR) from the control group. In 54 hypertensive children we found the following correlations: between office systolic and diastolic blood pressure and MPV (r = 0.35, p = 0.011, r = 0.36, p = 0.008), between 24-hour ambulatory mean arterial pressure Z-score and NLR (r = 0.30, p = 0.030), 24-hour systolic blood pressure load and NLR (r = 0.38, p = 0.005), plasma renin activity and neutrophil count, NLR, PLR (r = 0.47, p = 0.016, r = 0.64, p < 0.001, r = 0.42, p = 0.033), urinary albumin loss and neutrophil count, NLR (r = 0.46, p = 0.001 and r = 0.42, p = 0.003). Multivariate analysis revealed that office SBP Z-score was related to MPV (β = 0.35, p = 0.008) and albuminuria to neutrophil count (β = 0.62, p = 0.018).

Conclusions

In children with primary arterial hypertension there may be a relation between blood pressure, urinary albumin loss, and subclinical inflammation.

Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology

The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT₁R) is believed to mediate most functions of ANG II in the system. AT₁R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT₁R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT₁R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.

Targeting the renin-angiotensin system to improve cancer treatment: Implications for immunotherapy

Renin-angiotensin system (RAS) inhibitors (RASi)-widely prescribed for the treatment of cardiovascular diseases-have considerable potential in oncology. The RAS plays a crucial role in cancer biology and affects tumor growth and dissemination directly and indirectly by remodeling the tumor microenvironment. We review clinical data on the benefit of RASi in primary and metastatic tumors and propose that, by activating immunostimulatory pathways, these inhibitors can enhance immunotherapy of cancer.

Arachidonic acid and lipoxinA4 attenuate streptozotocin-induced cytotoxicity to RIN5 F cells in vitro and type 1 and type 2 diabetes mellitus in vivo

OBJECTIVE

The aim of this study was to observe whether polyunsaturated fatty acids (PUFAs) can protect rat insulinoma (RIN5 F) cells against streptozotocin (STZ)-induced apoptosis in vitro and type 1 diabetes mellitus (T1DM) and type 2 DM (T2DM) in vivo and if so, what would be the mechanism of this action.

METHODS

RIN5 F cells were used for the in vitro study, whereas the in vivo study was performed in Wistar rats. STZ was used to induce apoptosis of RIN5 F cells in vitro and T1- and T2DM in vivo. The effect of PUFAs: γ-linolenic acid (GLA), arachidonic acid (AA) of ω-6 series, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) of ω-3 series; cyclooxygenase (COX) and lipoxygenase (LOX) inhibitors and antiinflammatory metabolite of AA and DHA, lipoxin A4 (LXA4), and resolvin D2 and protectin, respectively against STZ-induced cytotoxicity to RIN5 F cells in vitro and LXA4 against T1- and T2DM in vivo was studied. Changes in the antioxidant content, lipid peroxides, nitric oxide, and expression of PDX1, P65, nuclear factor-κb (NF-κb), and IKB genes in STZ-treated RIN5 F cells in vitro and Nrf2, GLUT2, COX2, iNOS protein levels in the pancreatic tissue of T1- and T2DM and LPCLN2 (lipocalin 2), NF-κb, IKB I in adipose tissue of T2DM after LXA4 treatment were studied. Plasma glucose, insulin, and tumor necrosis factor (TNF)-α levels also were measured in STZ-induced T1- and T2DM Wistar rats.

RESULTS

Among all PUFAs tested, AA and EPA are the most effective against STZ-induced cytotoxicity to RIN5 F cells in vitro. Neither COX nor LOX inhibitors blocked the cytoprotective action of AA in vitro and T1- and T2DM by STZ. LXA4 production by RIN5 F cells in vitro and plasma LXA4 levels in STZ-induced T1- and T2DM animals were decreased by STZ that reverted to normal after AA treatment. AA prevented both T1- and T2DM induced by STZ. Antiinflammatory metabolite of AA and LXA4 prevented both T1- and T2DM induced by STZ. The expression of Pdx1, NF-κb, IKB genes in the pancreas and plasma TNF-α levels in T1- and T2DM; Nrf2, Glut2, COX2, and iNOS proteins in pancreatic tissue of T1DM and LPCLN2, NF-κb, IKB I in adipose tissue of T2DM reverted to normal in LXA4-treated animals.

CONCLUSION

Both AA and LXA4 prevented STZ-induced cytotoxicity to RIN5 F cells in vitro and T1- and T2DM in vivo, suggesting that these two bioactive lipids may function as antidiabetic molecules. AA is beneficial against STZ-induced cytotoxicity and T1- and T2DM by enhancing the production of LXA4.

Targeting Inflammation Through a Physical Active Lifestyle and Pharmaceuticals for the Treatment of Type 2 Diabetes

Evidence exists that interleukin (IL)-1β is involved in pancreatic β-cell damage, whereas TNF-α appears to be a key molecule in peripheral insulin resistance. Although increased plasma levels of IL-6 are seen in individuals with type 2 diabetes, mechanistic studies suggest that moderate acute elevations in IL-6, as provoked by exercise, exert anti-inflammatory effects by an inhibition of TNF-α and by stimulating IL-1 receptor antagonist (ra), thereby limiting IL-1β signaling. A number of medical treatments have anti-inflammatory effects. IL-1 antagonists have been tested in clinical studies and appear very promising. Also, there is a potential for anti-TNF-α strategies and salsalate has been shown to improve insulin sensitivity in clinical trials. Furthermore, the anti-inflammatory potential of statins, antagonists of the renin-angiotensin system, and glucose-lowering agents are discussed. While waiting for the outcome of long-term clinical pharmacological trials, it should be emphasized that physical activity represents a natural strong anti-inflammatory intervention with little or no side effects.

Insulin resistance pathogenesis in metabolic obesity

In this review we discuss the molecular mechanisms of insulin resistance concomitant with metabolic inflammation. We also analyze the world results of experimental and clinical studies which aimed at identifying the molecular targets for the development of new prevention and treatment of insulin resistance.

Targeting inflammation in the treatment of type 2 diabetes: time to start

The role of inflammation in the pathogenesis of type 2 diabetes and associated complications is now well established. Several conditions that are driven by inflammatory processes are also associated with diabetes, including rheumatoid arthritis, gout, psoriasis and Crohn's disease, and various anti-inflammatory drugs have been approved or are in late stages of development for the treatment of these conditions. This review discusses the rationale for the use of some of these anti-inflammatory treatments in patients with diabetes and what we could expect from their use. Future immunomodulatory treatments may not target a specific disease, but could instead act on a dysfunctional pathway that causes several conditions associated with the metabolic syndrome.

Valsartan slows the progression of diabetic nephropathy in db/db mice via a reduction in podocyte injury, and renal oxidative stress and inflammation

Higher doses of AngII (angiotensin II) blockers are intended to optimize albuminuria reduction rather than for blood pressure control in chronic kidney disease. However, the long-term renoprotection of high-dose AngII blockers has yet to be defined. The present study sought to determine whether doses of ARB (AngII receptor blocker) that maximally reduce proteinuria could slow the progression of glomerulosclerosis in the uninephrectomized db/db mouse, a model of Type 2 diabetes. Untreated uninephrectomized db/db mice had normal blood pressure, but developed progressive albuminuria and mesangial matrix expansion between 18 and 22 weeks of age, which was associated with increased renal expression of TGFβ1 (transforming growth factor β1), PAI-1 (plasminogen-activator inhibitor-1), type IV collagen and FN (fibronectin). Treatment with valsartan in the drinking water of db/db mice from 18 to 22 weeks of age, at a dose that was determined previously to maximally reduce proteinuria, prevented the increases in albuminuria and the markers of renal fibrosis seen in untreated db/db mice. In addition, WT-1 (Wilms tumour protein-1)-immunopositive podocyte numbers were found to be lower in the untreated glomeruli of mice with diabetes. The expression of podocin and nephrin were continually decreased in mice with diabetes between 18 and 22 weeks of age. These changes are indicative of podocyte injury and the administration of valsartan ameliorated them substantially. Renal expression of TNFα (tumour necrosis factor α), MCP-1 (monocyte chemoattractant protein-1), Nox2 (NADPH oxidase 2), p22phox and p47phox and urine TBARS (thiobarbituric acid-reacting substance) levels, the markers of renal inflammation and oxidative stress, were increased during disease progression in mice with diabetes. Valsartan treatment was shown to reduce these markers. Thus high doses of valsartan not only reduce albuminuria maximally, but also halt the progression of the glomerulosclerosis resulting from Type 2 diabetes via a reduction in podocyte injury and renal oxidative stress and inflammation.

Inflammation in obesity and diabetes: islet dysfunction and therapeutic opportunity

The role of the immune system is to restore functionality in response to stress. Increasing evidence shows that this function is not limited to insults by infection or injury and plays a role in response to overnutrition. Initially, this metabolic activation of the immune system is a physiological response, but it may become deleterious with time. Therefore, therapeutic interventions should aim at modulating the immune system rather than simply damping it. In this article, we describe the physiology and pathology of the immune system during obesity and diabetes with a focus on islet inflammation, the IL-1β pathway, and clinical translation.