Cell-specific insulin resistance: implications for atherosclerosis

Significance of Neutrophil to Lymphocyte Ratio (NLR) and Platelet Lymphocyte Ratio (PLR) in Diabetic Foot Ulcer and Potential New Therapeutic Targets

Diabetic foot ulcer (DFU) is a well-known complication of diabetes and a significant burden on the national health systems. The neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio are inexpensive and easily accessible biomarkers that have proved to be useful in several inflammatory, infectious and cardiovascular diseases. We carried out a comprehensive review examining the association of NLR and PLR with the onset and progression of DFU. PLR and NLR were significantly increased in patients with DFU, compared with a control group of T2DM patients without DFU, and correlate well with DFU severity, evaluated by Wagner and IWGDF grading scales. In patients with diabetic foot infections (DFI), elevated NLR and PLR were correlated with osteomyelitis, increased risk of amputation, and septic complications. The significance of the elevated value of these biomarkers in DFU is related to chronic hyperglycemia and low-grade systemic inflammation, atherosclerotic and vascular complications, and also the associated septic factor. Serial, dynamic follow-up can provide useful information in planning and monitoring DFU treatment, as well as in risk stratification of these vulnerable patients. Further randomized studies are needed to set the cut-off values with clinical significance.

Dietary Fruit and Vegetable Supplementation Suppresses Diet-Induced Atherosclerosis in LDL Receptor Knockout Mice

BACKGROUND

Epidemiologic studies suggest that fruit and vegetable (F&V) consumption is inversely associated with incidence of cardiovascular disease (CVD). However, evidence for causality is lacking, and the underlying mechanisms are not well understood.

OBJECTIVES

We aimed to determine whether there is a causal relation between consuming high levels of F&V and prevention of atherosclerosis, the hallmark of CVD pathogenesis. Furthermore, the underlying mechanisms were determined.

METHODS

Six-week-old male LDL receptor-knockout mice were randomly assigned to 3 diet groups (12 mice/group) for 20 wk: control (CON, 10% kcal fat, 0.20 g/kg cholesterol), atherogenic (Ath, 27% kcal fat, 0.55 g/kg cholesterol), and Ath supplemented with 15% F&V (Ath + FV) (equivalent to 8-9 servings/d in humans). F&V was added as a freeze-dried powder that was prepared from the 24 most commonly consumed F&Vs in the United States. Body weight, aortic atherosclerotic lesion area, hepatic steatosis area, serum lipid profile and proinflammatory cytokine TNF-α concentrations, gut microbiota, and liver TNF-α and fatty acid synthase (Fasn) mRNA concentrations were assessed.

RESULTS

F&V supplementation did not affect weight gain. Mice fed the Ath + FV diet had a smaller aortic atherosclerotic lesion area (71.7% less) and hepatic steatosis area (80.7% less) than those fed the Ath diet (both P < 0.001) independent of impact on weight, whereas no difference was found between Ath + FV and CON groups in these 2 pathologic markers. Furthermore, F&V supplementation prevented Ath diet-induced dyslipidemia (high concentrations of serum TG and VLDL cholesterol and lower concentrations of HDL cholesterol), reduced serum TNF-α concentration (by 21.5%), suppressed mRNA expression of liver TNF-α and Fasn, and ameliorated Ath-induced gut microbiota dysbiosis.

CONCLUSIONS

Our results indicate that consuming a large quantity and variety of F&Vs causally attenuates diet-induced atherosclerosis and hepatic steatosis in mice. These effects of F&Vs are associated with, and may be mediated through, improved atherogenic dyslipidemia, alleviated gut dysbiosis, and suppressed inflammation.

Endothelial Cell Metabolism

Endothelial cells (ECs) are more than inert blood vessel lining material. Instead, they are active players in the formation of new blood vessels (angiogenesis) both in health and (life-threatening) diseases. Recently, a new concept arose by which EC metabolism drives angiogenesis in parallel to well-established angiogenic growth factors (e.g., vascular endothelial growth factor). 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3-driven glycolysis generates energy to sustain competitive behavior of the ECs at the tip of a growing vessel sprout, whereas carnitine palmitoyltransferase 1a-controlled fatty acid oxidation regulates nucleotide synthesis and proliferation of ECs in the stalk of the sprout. To maintain vascular homeostasis, ECs rely on an intricate metabolic wiring characterized by intracellular compartmentalization, use metabolites for epigenetic regulation of EC subtype differentiation, crosstalk through metabolite release with other cell types, and exhibit EC subtype-specific metabolic traits. Importantly, maladaptation of EC metabolism contributes to vascular disorders, through EC dysfunction or excess angiogenesis, and presents new opportunities for anti-angiogenic strategies. Here we provide a comprehensive overview of established as well as newly uncovered aspects of EC metabolism.

Fructose induces prothrombotic phenotype in human endothelial cells : A new role for "added sugar" in cardio-metabolic risk

Intake of large amounts of added sweeteners has been associated with the pathogenesis of cardiometabolic risk. Several studies have shown that fructose increases the cardiovascular risk by modulating endothelial dysfunction and promoting atherosclerosis. Recently, a potential role for fructose in cardiovascular thrombosis has been suggested but with controversial results. Tissue factor (TF) plays a pivotal role in the pathophysiology of cardiovascular thrombosis by triggering the formation of intracoronary thrombi following endothelial injury. This study investigates the effects of fructose, in a concentration range usually observed in the plasma of patients with increased cardiovascular risk, on TF in human umbilical endothelial cells (HUVECs). Cells were stimulated with increasing concentrations of fructose (0.25, 1 and 2.5 mM) and then processed to evaluate TF-mRNA levels by real-time PCR as well as TF expression/activity by FACS analysis and procoagulant activity. Finally, a potential molecular pathway involved in modulating this phenomenon was investigated. We demonstrate that fructose induces transcription of mRNA for TF. In addition, we show that this monosaccharide promotes surface expression of TF that is functionally active. Fructose effects on TF appear modulated by the oxygen free radicals through activation of the transcription factor NF-κB since superoxide dismutase and NF-κB inhibitors suppressed TF expression. Data of the present study, although in vitro, indicate that fructose, besides promoting atherosclerosis, induces a prothrombotic phenotype in HUVECs, thus indicating one the mechanism(s) by which this sweetener might increase cardiometabolic risk.

The Combined Impact of Neutrophil-to-Lymphocyte Ratio and Type 2 Diabetic Mellitus on Significant Coronary Artery Disease and Carotid Artery Atherosclerosis

BACKGROUND

Neutrophil-to-lymphocyte ratio (NLR) has recently emerged as a new important inflammatory marker for predicting cardiovascular events. This study aimed to evaluate the combined impact of NLR and type 2 diabetes mellitus (T2DM) on significant coronary artery disease (CAD) and carotid artery atherosclerosis.

METHODS

This study includes a total of 828 patients evaluated by coronary angiography and carotid ultrasonography. Significant CAD was defined as at least one vessel with stenosis greater than 50%. We employed logistic regression models to investigate the association of NLR and T2DM with significant CAD. The goodness-of-fit and discriminability of the models were assessed by the loglikelihood ratio test and C-index, respectively. Also, we investigated the clinical relevance of the categorized NLR that classifies patients into three risk groups (low, intermediate, high).

RESULTS

According to logistic regression analysis, both NLR {adjusted odds ratio (OR) 1.31, p < 0.001} and T2DM (adjusted OR 2.46, p = 0.006) were independent risk factors of significant CAD. The addition of NLR and T2DM into a logistic regression model including conventional cardiovascular risk factors significantly improved the goodness-of-fit (p < 0.001) and the discriminability of the model (p = 0.004). Also, T2DM patients assigned into the high risk group (NLR > 2) showed the greater prevalence of significant CAD and carotid artery atherosclerosis compared with patients without T2DM or type 2 diabetic patients assigned into the low risk group (NLR ≤ 1).

CONCLUSION

Our results suggest that type 2 diabetic patients with high inflammatory state would be more vulnerable to significant CAD and carotid artery atherosclerosis.

Relationship between neutrophil-lymphocyte ratio and insulin resistance in newly diagnosed type 2 diabetes mellitus patients

BACKGROUND

Insulin resistance (IR) plays a vital role in the pathogenesis of Type 2 Diabetes Mellitus (T2DM). The mechanism of IR may be associated with inflammation, whereas the neutrophil-lymphocyte ratio (NLR) is a new indicator of subclinical inflammation. Scholars have rarely investigated the relationship between IR and NLR. This study aims to evaluate the relationship between IR and NLR, and determine whether or not NLR is a reliable marker for IR.

METHODS

The sample consists of a total of 413 patients with T2DM, 310 of whom have a HOMA-IR value of > 2.0. The control group consists of 130 age and BMI matched healthy subjects.

RESULTS

The NLR values of the diabetic patients were significantly higher than those of the healthy control (P < 0.001), and the NLR values of the patients with a HOMA-IR value of > 2.0 are notably greater than those of the patients with a HOMA-IR value of ≤ 2.0 (P < 0.001). Pearson correlation analysis showed a significant positive correlation of NLR with HOMA-IR (r = 0.285) (P < 0.001). Logistic regression analysis showed that the risk predictors of IR include NLR, TG and HbA1c. NLR (P < 0.001, EXP(B) = 7.231, 95% CI = 4.277-12.223) levels correlated positively with IR. The IR odds ratio increased by a factor of 7.231 (95% CI, 4.277-12.223) for every one unit increase in NLR.

CONCLUSIONS

Increased NLR was significantly associated with IR, and high NLR values may be a reliable predictive marker of IR.

White blood cell subtypes, insulin resistance and β-cell dysfunction in high-risk individuals--the PROMISE cohort

BACKGROUND

Higher white blood cell count (WBC) is associated with incident type 2 diabetes; however, little is known about the potential relationship of WBC subtypes with metabolic abnormalities underlying diabetes.

DESIGN

Cross-sectional analysis.

PARTICIPANTS

Six hundred and fifty-six nondiabetic participants in the Prospective Metabolism and Islet Cell Evaluation cohort.

MEASUREMENTS

Granulocytes (basophils, neutrophils and eosinophils), lymphocytes and monocytes were measured in fasting blood samples. Neutrophil lymphocyte ratio (NLR) is the ratio of neutrophil to lymphocyte. Insulin resistance was measured by insulin sensitivity index (ISOGTT) and homeostasis model assessment of insulin resistance (HOMA-IR). Beta-cell dysfunction was measured by insulinogenic index (IGI) divided by HOMA-IR (IGI/IR) and Insulin Secretion Sensitivity Index-2 (ISSI-2).

RESULTS

All WBC subtypes were inversely associated with ISOGTT [β = -0·12 (-0·15, -0·083) for granulocytes, β = -0·23 (-0·31, -0·15) for lymphocytes, β = -0·67 (-1·00, -0·34) for monocytes] and positively associated with HOMA-IR [β = 0·11 (0·074, 0·15) for granulocytes, β = 0·22 (0·14, 0·30) for lymphocytes, β = 0·64 (0·33, 0·97) for monocytes]. Granulocytes and lymphocytes were inversely associated with IGI/IR [β = -0·10 (-0·15, -0·047), β = -0·23 (-0·35, -0·11), respectively] and ISSI-2 [β = -0·048 (-0·074, -0·022), β = -0·14 (-0·19, -0·089), respectively]. BMI attenuated the associations of monocytes with IGI/IR and ISSI-2, and those of NLR with ISOGTT and HOMA-IR. NLR was not associated with IGI/IR and ISSI-2.

CONCLUSIONS

All WBC subtypes were independently associated with insulin resistance, whereas granulocytes and lymphocytes, but not monocytes, were associated with β-cell dysfunction. NLR was not associated with β-cell dysfunction, and its association with insulin resistance was confounded by obesity.

Fructose and uric acid: is there a role in endothelial function?

Population level data support that consumption of fructose and fructose-based sweeteners has dramatically increased and suggest that high dietary intake of fructose is an important factor in the development of the cardiorenal metabolic syndrome (CRS). The CRS is a constellation of cardiac, kidney and metabolic disorders including insulin resistance, obesity, metabolic dyslipidemia, high blood pressure, and evidence of early cardiac and kidney disease. The consequences of fructose metabolism may result in intracellular ATP depletion, increased uric acid production, oxidative stress, inflammation, and increased lipogenesis, which are associated with endothelial dysfunction. Endothelial dysfunction is an early manifestation of vascular disease and a driver for the development of CRS. A better understanding of fructose overconsumption in the development of CRS may provide new insights into pathogenesis and future therapeutic strategies.

Effect of low-intensity ergometer aerobic training on glucose tolerance in severely impaired nondiabetic stroke patients

OBJECTIVE

To investigate whether low-intensity ergometer aerobic training has beneficial effect on glucose tolerance in nondiabetic patients with severely impaired stroke.

METHODS

Fifty-four severely impaired stroke survivors were recruited and randomly assigned to the experimental group and control group. They have no diabetes history with fasting plasma glucose less than 7 mmol/L. Both groups participated in a 6-week rehabilitation training program with low-intensity ergometer aerobic training added only in the experimental group 3 times per week. Primary outcome variables were fasting glucose, fasting insulin, 2-hour glucose, and homeostasis model assessment-insulin resistance (HOMA-IR) in oral glucose tolerance test before and after intervention.

RESULTS

Before intervention, 36 of 54 (66.7%) were diagnosed with impaired glucose status or diabetic glucose tolerance totally. The average 2-hour plasma glucose level was 9.14 ± 1.39 mmol/L. After intervention, aerobic training significantly improved fasting insulin (from 8.51 ± 2.01 μU/mL to 7.11 ± 2.02 μU/mL), 2-hour glucose level (from 9.13 ± 1.14 mmol/L to 7.22 ± 1.23 mmol/L), and HOMA-IR (from 1.62 ± 1.01 to 1.29 ± .79) in the intervention group compared with the control group (P < .05). Aerobic training also significantly improved their glucose tolerance state (P < .05).

CONCLUSIONS

Preliminary findings suggest that abnormal glucose tolerance may be highly present among severely impaired nondiabetic stroke patients and low-intensity ergometer aerobic training may have beneficial role in improving glucose tolerance.

Targeting insulin resistance in type 2 diabetes via immune modulation of cord blood-derived multipotent stem cells (CB-SCs) in stem cell educator therapy: phase I/II clinical trial

BACKGROUND

The prevalence of type 2 diabetes (T2D) is increasing worldwide and creating a significant burden on health systems, highlighting the need for the development of innovative therapeutic approaches to overcome immune dysfunction, which is likely a key factor in the development of insulin resistance in T2D. It suggests that immune modulation may be a useful tool in treating the disease.

METHODS

In an open-label, phase 1/phase 2 study, patients (N=36) with long-standing T2D were divided into three groups (Group A, oral medications, n=18; Group B, oral medications+insulin injections, n=11; Group C having impaired β-cell function with oral medications+insulin injections, n=7). All patients received one treatment with the Stem Cell Educator therapy in which a patient's blood is circulated through a closed-loop system that separates mononuclear cells from the whole blood, briefly co-cultures them with adherent cord blood-derived multipotent stem cells (CB-SCs), and returns the educated autologous cells to the patient's circulation.

RESULTS

Clinical findings indicate that T2D patients achieve improved metabolic control and reduced inflammation markers after receiving Stem Cell Educator therapy. Median glycated hemoglobin (HbA1C) in Group A and B was significantly reduced from 8.61%±1.12 at baseline to 7.25%±0.58 at 12 weeks (P=2.62E-06), and 7.33%±1.02 at one year post-treatment (P=0.0002). Homeostasis model assessment (HOMA) of insulin resistance (HOMA-IR) demonstrated that insulin sensitivity was improved post-treatment. Notably, the islet beta-cell function in Group C subjects was markedly recovered, as demonstrated by the restoration of C-peptide levels. Mechanistic studies revealed that Stem Cell Educator therapy reverses immune dysfunctions through immune modulation on monocytes and balancing Th1/Th2/Th3 cytokine production.

CONCLUSIONS

Clinical data from the current phase 1/phase 2 study demonstrate that Stem Cell Educator therapy is a safe approach that produces lasting improvement in metabolic control for individuals with moderate or severe T2D who receive a single treatment. In addition, this approach does not appear to have the safety and ethical concerns associated with conventional stem cell-based approaches.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT01415726.