Novel Associations of Dyslipidaemia with Vitamin D and Bone Metabolism in Elderly Patients with Diabetes: A Cross-Sectional Study

Objective

Little is known about whether diabetic dyslipidaemia contributes to increased bone fragility in patients with diabetes. This study aimed to explore the potential effects of dyslipidaemia on vitamin D and bone metabolism in elderly subjects with type 2 diabetes (T2D).

Methods

A total of 1479 male patients and 1356 female patients 50 years or older with T2D were included in Shanghai, China. Lipid profiles, 25-hydroxyvitamin D (25(OH)D), serum procollagen type I N-terminal propeptide (P1NP), β-C-terminal telopeptide (β-CTX) and other parameters were measured. Principal component regression (PCR) and mediation analysis were used to estimate the associations of lipid profile, 25(OH)D and bone turnover levels.

Results

Female patients presented with higher blood lipids, lower 25(OH)D, and higher P1NP and β-CTX levels than male patients with T2D. TC was associated with P1NP in males and females (β=0.056, P<0.05; β=0.095, P<0.01, respectively), and 25(OH)D fully mediated the associations in males and mediated approximately 17.89% of the effects in females. LDL-C was associated with P1NP in males and females (β=0.072 and 0.105 respectively, all P<0.01), and 25(OH)D mediated the relationships approximately 20.83% in males and 14.29% in females. TG was negatively associated with P1NP (in males, β= -0.063, P<0.05; in females, β= -0.100, P<0.01) and β-CTX (in males, β= -0.108; in females, β= -0.128, all P<0.01) independent of 25(OH)D, while HDL-C was not associated with P1NP or β-CTX in diabetic patients.

Conclusion

Hypercholesterolemia and hypertriglyceridaemia might affect bone metabolism by distinguishing pathways in diabetes patients. Ameliorating lipid control in elderly diabetes patients, especially female patients, will benefit both vitamin D and bone metabolism.

Diabetes Mellitus Type 2 Patients with Abdominal Obesity Are Prone to Osteodysfunction: A Cross-Sectional Study

Introduction

The interaction between diabetes, obesity, and bone metabolism was drawing increasing public attention. However, the osteometabolic changes in diabetes mellitus type 2 (T2DM) patients with abdominal obesity have not been fully revealed. This study is aimed at investigating the association between abdominal obesity indices and bone turnover markers among T2DM participants.

Methods

4351 subjects were involved in the METAL study. Abdominal obesity indices included neck, waist, and hip circumference, visceral adiposity index (VAI), lipid accumulation product (LAP), waist-to-hip ratio (WHR), and Chinese visceral adiposity index (CVAI). They were applied to elucidate the nexus between β-C-terminal telopeptide (β-CTX), osteocalcin (OC), and intact N-terminal propeptide of type I collagen (P1NP).

Results

Abdominal obesity indices were strongly negatively associated with β-CTX and OC. Among males, five indices were negatively correlated with β-CTX (BMI, WC, LAP, WHR, and CVAI) and OC (BMI, NC, WC, WHR, and CVAI). There were no significant associations with P1NP. Among females, all eight indices were negatively associated with β-CTX. Seven indices were negatively related to OC (BMI, NC, WC, HC, LAP, WHR, and CVAI). The VAI was negatively correlated with P1NP.

Conclusions

The present study demonstrated that in T2DM, abdominal obesity had an obviously negative correlation with bone metabolism. Abdominal obesity indices were significantly negatively associated with skeletal destruction (β-CTX) and formation (OC). In routine clinical practice, these easily obtained indices could be used as a preliminary screening method and relevant factors for osteodysfunction incidence risk at no additional cost and may be of particular value for postmenopausal women in T2DM populations.

Positive association of glucagon with bone turnover markers in type 2 diabetes: A cross-sectional study

AIMS

The osteo-metabolic changes in type 2 diabetes (T2D) patients are intricate and have not been fully revealed. It is not clear whether glucagon is entirely harmful in the pathogenesis of diabetes or a possible endocrine counter-regulation mechanism to reverse some abnormal bone metabolism. This study aimed to investigate the association between glucagon and bone turnover markers (BTMs) in T2D patients.

METHODS

A total of 3984 T2D participants were involved in a cross-sectional study in Shanghai, China. Serum glucagon was measured to elucidate its associations with intact N-terminal propeptide of type I collagen (P1NP), osteocalcin (OC), and β-C-terminal telopeptide (β-CTX). Glucagon was detected with a radioimmunoassay. Propeptide of type I collagen, OC, and β-CTX were detected using chemiluminescence. The diagnosis of T2D was based on American Diabetes Association criteria.

RESULTS

The concentration of glucagon was positively correlated with two BTMs [OC-β: 0.034, 95% CI: 0.004, 0.051, p = 0.024; CTX-β: 0.035, 95% CI: 0.004, 0.062, p = 0.024]. The result of P1NP was [P1NP-regression coefficient (β): 0.027, 95% CI: -0.003, 0.049, p = 0.083]. In the glucagon tertiles, P for trend of the BTMs is [P1NP: 0.031; OC: 0.038; CTX: 0.020], respectively.

CONCLUSIONS

Glucagon had a positive effect on bone metabolism. The concentrations of the three BTMs increased as glucagon concentrations rose. This implied that glucagon might speed up skeletal remodelling, accelerate osteogenesis, and promote the formation of mature bone tissue. At the same time, the osteoclastic process was also accelerated, providing raw materials for osteogenesis to preserve the dynamic balance. In view of the successful use of single-molecule as well as dual/triple agonists, it would be feasible to develop a preparation that would reduce osteoporosis in diabetic patients.

FSH may mediate the association between HbA1c and bone turnover markers in postmenopausal women with type 2 diabetes

INTRODUCTION

Recent studies in postmenopausal women have found associations of follicle-stimulating hormone (FSH) levels with both glucose metabolism and bone turnover. The objective of the study was to investigate whether FSH may contribute to suppressed bone turnover markers (BTMs) in postmenopausal women with type 2 diabetes (T2D).

MATERIALS AND METHODS

888 postmenopausal women with T2D, 352 nondiabetes (prediabetes plus normoglycemia) were included from the METAL study. HbA1c, sex hormones, 25-hydroxy vitamin D (25(OH)D), serum procollagen type I N-terminal propeptide (P1NP), and β-C-terminal telopeptide (β-CTX) were measured.

RESULTS

P1NP and β-CTX decreased in postmenopausal T2D women compared with nondiabetes controls (both p < 0.001). The major factors responsible for the changes in P1NP were HbA1c (β = - 0.050, p < 0.001), 25(OH)D (β = - 0.003, p = 0.006), FSH (β = 0.001, p = 0.044) and metformin (β = - 0.109, p < 0.001), for β-CTX were HbA1c (β = - 0.049, p < 0.001), body mass index (BMI) (β = - 0.011, p = 0.005), 25(OH)D (β = - 0.003, p = 0.003), FSH (β = 0.002, p = 0.022) and metformin (β = - 0.091, p = 0.001) in postmenopausal T2D women based on multivariate regression analysis. With the increase in HbA1c, FSH decreased significantly (p for trend < 0.001). Mediation analysis demonstrated that FSH partly mediated the suppression of LnP1NP and Lnβ-CTX by HbA1c (β = - 0.009 and - 0.010, respectively), and Lnβ-CTX by BMI (β = - 0.015) when multiple confounders were considered (all p < 0.05).

CONCLUSION

HbA1c was the crucial determinant contributing to the suppression of BTMs. FSH might play a novel mediation role in BTM suppression due to HbA1c or BMI.

Sex-specific plasticity in CRF regulation of inhibitory control in central amygdala CRF1 neurons after chronic voluntary alcohol drinking

Despite strong preclinical evidence for the ability of corticotropin releasing factor 1 (CRF1) antagonists to regulate alcohol consumption, clinical trials have not yet demonstrated therapeutic effects of these compounds in alcohol use disorder (AUD) patients. Several confounding factors may limit the translation of preclinical CRF1 research to patients, including reliance on experimenter-administered alcohol instead of voluntary consumption, a preponderance of evidence collected in male subjects only and an inability to assess the effects of alcohol on specific brain circuits. A population of particular interest is the CRF1-containing neurons of the central amygdala (CeA). CRF1 CeA neurons are sensitive to ethanol, but the effects of alcohol drinking on CRF signalling within this population are unknown. In the present study, we assessed the effects of voluntary alcohol drinking on inhibitory control of CRF1+ CeA neurons from male and female CRF1:GFP mice using ex vivo electrophysiology and determined the contributions of CRF1 signalling to inhibitory control and voluntary alcohol drinking. Chronic alcohol drinking produced neuroadaptations in CRF1+ neurons that increased the sensitivity of GABA_A receptor-mediated sIPSCs to the acute effects of alcohol, CRF and the CRF1 antagonist R121919, but these adaptations were more pronounced in male versus female mice. The CRF1 antagonist CP-154,526 reduced voluntary alcohol drinking in both sexes and abolished sex differences in alcohol drinking. The lack of alcohol-induced adaptation in the female CRF1 system may be related to the elevated alcohol intake exhibited by female mice and could contribute to the ineffectiveness of CRF1 antagonists in female AUD patients.

Association of Insulin Resistance and β-cell Function With Bone Turnover Biomarkers in Dysglycemia Patients

BACKGROUND

The interrelation between glucose and bone metabolism is complex and has not been fully revealed. This study aimed to investigate the association between insulin resistance, β-cell function and bone turnover biomarker levels among participants with abnormal glycometabolism.

METHODS

A total of 5277 subjects were involved through a cross-sectional study (METAL study, http://www.chictr.org.cn, ChiCTR1800017573) in Shanghai, China. Homeostasis model assessment of insulin resistance (HOMA-IR) and β-cell dysfunction (HOMA-%β) were applied to elucidate the nexus between β-C-terminal telopeptide (β-CTX), intact N-terminal propeptide of type I collagen (P1NP) and osteocalcin (OC). β-CTX, OC and P1NP were detected by chemiluminescence.

RESULTS

HOMA-IR was negatively associated with β-CTX, P1NP and OC (regression coefficient (β) -0.044 (-0.053, -0.035), Q4vsQ1; β -7.340 (-9.130, -5.550), Q4vsQ1 and β -2.885 (-3.357, -2.412), Q4vsQ1, respectively, all P for trend <0.001). HOMA-%β was positively associated with β-CTX, P1NP and OC (β 0.022 (0.014, 0.031), Q4vsQ1; β 6.951 (5.300, 8.602), Q4vsQ1 and β 1.361 (0.921, 1.800), Q4vsQ1, respectively, all P for trend <0.001).

CONCLUSIONS

Our results support that lower bone turnover biomarker (β-CTX, P1NP and OC) levels were associated with a combination of higher prevalence of insulin resistance and worse β-cell function among dysglycemia patients. It is feasible to detect bone turnover in diabetes or hyperglycemia patients to predict the risk of osteoporosis and fracture, relieve patients' pain and reduce the expenses of long-term cure.

Circulating levels of mitochondrial uncoupling protein 2, but not prohibitin, are lower in humans with type 2 diabetes and correlate with brachial artery flow-mediated dilation

BACKGROUND

Excessive reactive oxygen species from endothelial mitochondria in type 2 diabetes individuals (T2DM) may occur through multiple related mechanisms, including production of mitochondrial reactive oxygen species (mtROS), inner mitochondrial membrane (Δψ_m) hyperpolarization, changes in mitochondrial mass and membrane composition, and fission of the mitochondrial networks. Inner mitochondrial membrane proteins uncoupling protein-2 (UCP2) and prohibitin (PHB) can favorably impact mtROS and mitochondrial membrane potential (Δψ_m). Circulating levels of UCP2 and PHB could potentially serve as biomarker surrogates for vascular health in patients with and without T2DM.

METHODS

Plasma samples and data from a total of 107 individuals with (N = 52) and without T2DM (N = 55) were included in this study. Brachial artery flow mediated dilation (FMD) was measured by ultrasound. ELISA was performed to measure serum concentrations of PHB1 and UCP2. Mitochondrial membrane potential was measured from isolated leukocytes using JC-1 dye.

RESULTS

Serum UCP2 levels were significantly lower in T2DM subjects compared to control subjects (3.01 ± 0.34 vs. 4.11 ± 0.41 ng/mL, P = 0.04). There were no significant differences in levels of serum PHB. UCP2 levels significantly and positively correlated with FMDmm (r = 0.30, P = 0.03) in T2DM subjects only and remained significant after multivariable adjustment. Within T2DM subjects, serum PHB levels were significantly and negatively correlated with UCP2 levels (ρ = - 0.35, P = 0.03).

CONCLUSION

Circulating UCP2 levels are lower in T2DM patients and correlate with endothelium-dependent vasodilation in conduit vessels. UCP2 could be biomarker surrogate for overall vascular health in patients with T2DM and merits additional investigation.

Lactobacillus plantarum 299v Supplementation Improves Vascular Endothelial Function and Reduces Inflammatory Biomarkers in Men With Stable Coronary Artery Disease

RATIONALE

A strong association has emerged between the gut microbiome and atherosclerotic disease. Our recent data suggest Lactobacillus plantarum 299v (Lp299v) supplementation reduces infarct size in male rats. Limited human data are available on the impact of Lp299v on the vasculature.

OBJECTIVE

To determine whether oral Lp299v supplementation improves vascular endothelial function and reduces systemic inflammation in humans with stable coronary artery disease (CAD).

METHODS AND RESULTS

Twenty men with stable CAD consumed a drink containing Lp299v (20 billion CFU) once daily for 6 weeks. After a 4-week washout, subjects were given an option of additionally participating in a 10-day study of oral liquid vancomycin (250 mg QID). Vascular endothelial function was measured by brachial artery flow-mediated dilation. Before and after Lp299v, plasma short-chain fatty acids, trimethylamine oxide, and adipokine levels were measured. Additional plasma samples underwent unbiased metabolomic analyses using liquid chromatography/mass spectroscopy. 16S rRNA sequencing was used to determine changes of the stool microbiome. Arterioles from patients with CAD were obtained, and endothelium-dependent vasodilation was measured by video microscopy after intraluminal incubation with plasma from Lp299v study subjects. Lp299v supplementation improved brachial flow-mediated dilation ( P=0.008) without significant changes in plasma cholesterol profiles, fasting glucose, or body mass index. Vancomycin did not impact flow-mediated dilation. Lp299v supplementation decreased circulating levels of IL (interleukin)-8 ( P=0.01), IL-12 ( P=0.02), and leptin ( P=0.0007) but did not significantly change plasma trimethylamine oxide concentrations ( P=0.27). Plasma propionate ( P=0.004) increased, whereas acetate levels decreased ( P=0.03). Post-Lp299v plasma improved endothelium-dependent vasodilation in resistance arteries from patients with CAD ( P=0.02).16S rRNA analysis showed the Lactobacillus genus was enriched in postprobiotic stool samples without other changes.

CONCLUSIONS

Lp299v improved vascular endothelial function and decreased systemic inflammation in men with CAD, independent of changes in traditional risk factors and trimethylamine oxide. Circulating gut-derived metabolites likely account for these improvements and merit further study.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01952834.

miR-29 contributes to normal endothelial function and can restore it in cardiometabolic disorders

We investigated the role of microRNAs (miRNA) in endothelial dysfunction in the setting of cardiometabolic disorders represented by type 2 diabetes mellitus (T2DM). miR‐29 was dysregulated in resistance arterioles obtained by biopsy in T2DM patients. Intraluminal delivery of miR‐29a‐3p or miR‐29b‐3p mimics restored normal endothelium‐dependent vasodilation (EDVD) in T2DM arterioles that otherwise exhibited impaired EDVD. Intraluminal delivery of anti‐miR‐29b‐3p in arterioles from non‐DM human subjects or rats or targeted mutation of Mir29b‐1/a gene in rats led to impaired EDVD and exacerbation of hypertension in the rats. miR‐29b‐3p mimic increased, while anti‐miR‐29b‐3p or Mir29b‐1/a gene mutation decreased, nitric oxide levels in arterioles. The mutation of Mir29b‐1/a gene led to preferential differential expression of genes related to nitric oxide including Lypla1. Lypla1 was a direct target of miR‐29 and could abrogate the effect of miR‐29 in promoting nitric oxide production. Treatment with Lypla1 siRNA improved EDVD in arterioles obtained from T2DM patients or Mir29b‐1/a mutant rats or treated with anti‐miR‐29b‐3p. These findings indicate miR‐29 is required for normal endothelial function in humans and animal models and has therapeutic potential for cardiometabolic disorders.

Abstract 059: miR-29 is Required for Normal Endothelium-dependent Vasodilation and Protects Against Hypertension

MicroRNA miR-29 is down-regulated in Dahl salt-sensitive (SS) rats compared to salt-insensitive SS-13 BN rats. We investigated the role of miR-29 in endothelial function and the development of hypertension. Using TALENs (Transcriptional Activator-Like Effector Nucleases) we deleted 4 nucleotides from Mir29b-1 gene in SS-13 BN rats. The targeted mutation resulted in reduced abundance of miR-29b-3p and the co-transcribed miR-29a-3p in arteriolar endothelial cells. When stimulated with acetylcholine to induce endothelium-dependent vasodilation (EDVD), gluteal arterioles from Mir29b-1 -/- rats were only able to dilate to an average 47% of maximum diameter while wild-type littermates dilated to 77% (N=7 and 9, respectively, p<0.05). The development of hypertension was significantly exacerbated in Mir29b-1 -/- compared to Mir29b-1 +/+ littermates. Mean arterial blood pressure was 129 ± 2 mmHg in Mir29b-1 +/+ rats after 2 weeks of 4% NaCl diet and 140 ± 5 mmHg in Mir29b-1 -/- rats (N=6, 10, respectively, p<0.05). Gluteal arterioles from Mir29b-1 -/- rats exhibited significantly reduced nitric oxide (NO) levels compared to Mir29b-1 +/+ littermates as measured by DAF2-DA intensity (N=6, 11, respectively). Mutation of the Mir29b-1 gene resulted in preferential differential expression of genes in arterioles related to the regulation of NO levels including Lypla1. Lypla1 is a direct target of miR-29 and could abrogate the effect of miR-29 in promoting NO production. Reduction of LYPLA1 by transfection of pre-miR-29b or a Lypla1 siRNA resulted in a significant increase in NO as measured by DAF2-DA in cultured human dermal microvascular endothelial cells. Taken together, we have shown that targeted mutation of Mir29b-1 reduces EDVD and exacerbates the development of hypertension. We have identified a mechanism by which miR-29 affects NO production. These findings indicate miR-29 is required for normal endothelial function in rats and has therapeutic potential for hypertension.

Impact of DPP-4 inhibition on acute and chronic endothelial function in humans with type 2 diabetes on background metformin therapy

Cell culture and animal work indicate that dipeptidyl peptidase-4 (DPP-4) inhibition may exert cardiovascular benefits through favorable effects on the vascular endothelium. Prior human studies evaluating DPP-4 inhibition have shown conflicting results that may in part be related to heterogeneity of background anti-diabetes therapies. No study has evaluated the acute response of the vasculature to DPP-4 inhibition in humans. We recruited 38 patients with type 2 diabetes on stable background metformin therapy for a randomized, double-blind, placebo-controlled crossover trial of DPP-4 inhibition with sitagliptin (100 mg/day). Each treatment period was 8 weeks long separated by 4 weeks of washout. Endothelial function and plasma markers of endothelial activation (intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1)) were measured prior to and 2 hours following acute dosing of sitagliptin or placebo, as well as following 8 weeks of intervention with each pill. Thirty subjects completed the study and were included in analyses. Neither acute nor chronic sitagliptin therapy resulted in significant changes in vascular endothelial function. While post-acute sitagliptin ICAM-1 levels were lower than that post-chronic sitagliptin, the ICAM-1 concentration was not significantly different than pre-acute sitagliptin levels or levels measured in relationship to placebo. There were no significant changes in plasma VCAM-1 levels at any time point. Acute and chronic sitagliptin therapies have neutral effects on the vascular endothelium in the setting of metformin background therapy. In conclusion, our findings suggest DPP-4 inhibition has a neutral effect on cardiovascular risk in patients without a history of heart failure or renal insufficiency.

TRIAL REGISTRATION

NCT01859793.

Dynamin-related protein 1 mediates low glucose-induced endothelial dysfunction in human arterioles

Intensive glycemic regulation has resulted in an increased incidence of hypoglycemia. Hypoglycemic burden correlates with adverse cardiovascular complications and contributes acutely and chronically to endothelial dysfunction. Prior data indicate that mitochondrial dysfunction contributes to hypoglycemia-induced endothelial dysfunction, but the mechanisms behind this linkage remain unknown. We attempt to determine whether clinically relevant low-glucose (LG) exposures acutely induce endothelial dysfunction through activation of the mitochondrial fission process. Characterization of mitochondrial morphology was carried out in cultured endothelial cells by using confocal microscopy. Isolated human arterioles were used to explore the effect LG-induced mitochondrial fission has on the formation of detrimental reactive oxygen species (ROS), bioavailability of nitric oxide (NO), and endothelial-dependent vascular relaxation. Fluorescence microscopy was employed to visualize changes in mitochondrial ROS and NO levels and videomicroscopy applied to measure vasodilation response. Pharmacological disruption of the profission protein Drp1 with Mdivi-1 during LG exposure reduced mitochondrial fragmentation among vascular endothelial cells (LG: 0.469; LG+Mdivi-1: 0.276; P = 0.003), prevented formation of vascular ROS (LG: 2.036; LG+Mdivi-1: 1.774; P = 0.005), increased the presence of NO (LG: 1.352; LG+Mdivi-1: 1.502; P = 0.048), and improved vascular dilation response to acetylcholine (LG: 31.6%; LG+Mdivi-1; 78.5% at maximum dose; P < 0.001). Additionally, decreased expression of Drp1 via siRNA knockdown during LG conditions also improved vascular relaxation. Exposure to LG imparts endothelial dysfunction coupled with altered mitochondrial phenotypes among isolated human arterioles. Disruption of Drp1 and subsequent mitochondrial fragmentation events prevents impaired vascular dilation, restores mitochondrial phenotype, and implicates mitochondrial fission as a primary mediator of LG-induced endothelial dysfunction.NEW & NOTEWORTHY Acute low-glucose exposure induces mitochondrial fragmentation in endothelial cells via Drp1 and is associated with impaired endothelial function in human arterioles. Targeting of Drp1 prevents fragmentation, improves vasofunction, and may provide a therapeutic target for improving cardiovascular complications among diabetics.Listen to this article's corresponding podcast @ http://ajpheart.podbean.com/e/mitochondrial-dynamics-impact-endothelial-function/.

Expression and prognostic significance of ELL-associated factor 2 in human prostate cancer

PURPOSE

ELL-associated factor 2 (EAF2) is an androgen-regulated tumor suppressor in the prostate. The purpose of this study was to investigate the expression of EAF2 protein in human prostate cancer specimens along with BPH specimens as a control, and to evaluate potential association of EAF2 expression with clinical characteristics and overall survival of the prostate cancer patients.

METHODS

The expression of EAF2 was evaluated in 44 prostate cancer and 23 BPH tissue specimens using immunohistochemistry. The relationships of EAF2 expression with clinical characteristics and overall survival rates were analyzed by Chi-square test and Kaplan-Meier method.

RESULTS

The immunostaining intensity of EAF2 in BPH specimens was significantly higher than that in prostate cancer (p < 0.05). EAF2 expression decreased significantly in high-grade and advanced-stage human prostate tumors and inversely correlated with PSA level, Gleason scores, bone metastasis and tumor stage. Importantly, loss of EAF2 expression was associated with a significant decrease in patient survival.

CONCLUSION

Expression of EAF2 is decreased in prostate carcinogenesis, and EAF2 loss is associated with high-risk patients and poor survival.

Abstract P124: Human Small Artery MicroRNA Expression Profiles: Changes in Type 2 Diabetes and Associations with Endothelial Function

Background: Studies of experimental models and human blood samples support an important role of microRNAs (miRNAs) in the development of vascular dysfunction in hypertension and diabetes mellitus (DM). Information on miRNA expression in clinically directly relevant tissues such as human small arteries and its relationship with impaired vascular endothelial function is currently lacking.

Methods and Results: 38 subjects (18 type 2 DM, 20 controls) underwent gluteal adipose pad biopsy to obtain small arteries for miRNA expression profiling by small RNA deep sequencing. In vivo conduit artery endothelial function was measured by brachial artery reactivity. In vitro microvascular endothelium dependent vasodilation was measured by videomicroscopy. Correlations between miRNA expression and measurements of endothelial function were calculated using generalized linear models. Several miRNAs correlated with measurements of vascular structure and function. Endothelium dependent vasodilation was impaired in type 2 DM subjects compared to controls based on both the vasodilatory response to peak dose acetylcholine (44±25 vs. 69±18 %, P=0.04) and by analyses of the entire acetylcholine dose-response curve. Several miRNAs were differentially expressed in small arteries from type 2 DM subjects, two of which were verified by real-time PCR. Cross-referencing the top 30 miRNAs (P<0.015) with prior studies of plasma miRNA expression in DM subjects identified 7 miRNAs differentially expressed in both human small arteries and plasma, all of which have some reported role in vascular regulation.

Conclusions: Multiple miRNAs are differentially expressed in human small arteries in DM patients and correlated with in vivo or in vitro measurements of endothelial function, suggesting an important role of microvascular miRNAs in the development of endothelial dysfunction in humans.

Mineralocorticoid exposure and receptor activity modulate microvascular endothelial function in African Americans with and without hypertension

Prior work suggests blood pressure in African Americans is more sensitive to the effects of aldosterone than in Caucasians. This mechanism may relate to a negative response of the vascular endothelium to aldosterone, including reduced glucose-6-phosphate dehydrogenase (G6PD) activity. Thirty-three African Americans (11 hypertensives, 22 controls) without evidence of diabetes or metabolic syndrome completed the protocol. The protocol included measurement of in vivo microvascular endothelial function by digital pulse arterial tonometry and ex vivo measurement of endothelial function by videomicroscopy of arterioles obtained from these same subjects with and without exposure to aldosterone or spironolactone. Systemic and arteriolar G6PD activities were also measured. In vivo and ex vivo microvascular endothelial function were impaired in African Americans with hypertension. One-hour exposure with aldosterone impaired endothelium-dependent vasodilation in arterioles from normotensive subjects, while 1 hour of spironolactone exposure reversed endothelial dysfunction in arterioles from hypertensive subjects. G6PD activity was impaired in hypertensive arterioles. Aldosterone-related endothelial dysfunction may be responsible for at least a portion of the greater blood pressure sensitivity to aldosterone in African Americans. This may be in part related to vascular suppression of G6PD activity.

Moderate Obesity and Endothelial Dysfunction in Humans: Influence of Gender and Systemic Inflammation

Our objective was to determine whether moderate obesity (Body Mass Index [BMI] ≥ 30 kg/m²) is associated with impaired conduit and microvascular endothelial function, and whether men or women are more susceptible to impairment of endothelial function related to moderate obesity. Forty-one middle aged, nondiabetic moderately obese (BMI 34.7 ± 4.0 kg/m²) and nonobese (BMI 24.3 ± 2.6 kg/m²) subjects of both sexes underwent noninvasive studies of endothelial function (brachial reactivity) and measurements of endothelial-dependent vasodilation of gluteal subcutaneous arterioles to acetylcholine (Ach). Endothelium-dependent vasodilation to Ach was decreased in the moderately obese compared with the nonobese (P < 0.001). Stratified analysis based on sex showed impairment of arteriolar endothelial function in women BMI ≥ 30 kg/m² (P = 0.02), but not men. There was no difference between in vivo endothelial function flow-mediated dilation (FMD%) by BMI category. Sex-specific analysis showed FMD% was lower in women with BMI ≥ 30 kg/m² compared to those with BMI < 30 kg/m² (P = 0.02). No differences were seen in men based on BMI category (P = 0.18). In women, high sensitivity C-reactive protein (hsCRP) correlated with BMI (ρ = 0.68, P = 0.006). Moderate obesity is associated with impaired resistance arteriolar endothelial function. This is more prominent in women than men and is associated with systemic inflammation.

Adverse alterations in mitochondrial function contribute to type 2 diabetes mellitus-related endothelial dysfunction in humans

OBJECTIVE

Mitochondrial dysfunction plays a key pathophysiological role in type 2 diabetes mellitus (T2DM). Data delineating relationships between mitochondrial and endothelial dysfunction in humans with T2DM are lacking.

METHODS AND RESULTS

In 122 human subjects (60 with T2DM, 62 without T2DM), we measured endothelial function by brachial artery ultrasound (flow mediated dilation) and digital pulse amplitude tonometery. Endothelial function in arterioles isolated from gluteal subcutaneous adipose was measured by videomicroscopy. In arterioles and mononuclear cells, we measured inner mitochondrial membrane potential (Δψ(m)), mitochondrial mass, and mitochondrial superoxide production using fluorophores. Endothelial function was impaired in T2DM subjects versus control subjects. Δψ(m) magnitude was larger and mitochondrial mass was lower in arterioles and mononuclear cells in T2DM. Mononuclear mitochondrial mass correlated with flow-mediated dilation and pulse amplitude tonometery (ρ=0.38 and 0.33, P=0.001 and 0.02, respectively), and mononuclear mitochondrial superoxide production inversely correlated with flow-mediated dilation (ρ=-0.58, P=0.03). Low doses of 2 different mitochondrial uncoupling agents (carbonyl cyanide m-chlorophenyl hydrazone and 2,4-dinitrophenol) that reduce Δψ(m) magnitude and a mitochondrial-targeted antioxidant (MitoTEMPOL) improved endothelial function and reduced mitochondrial superoxide levels in T2DM arterioles.

CONCLUSIONS

Mitochondrial dysfunction may play a central role in the impairment of endothelial dysfunction in T2DM.

Nitric oxide synthase-dependent vasodilation of human subcutaneous arterioles correlates with noninvasive measurements of endothelial function

BACKGROUND

Noninvasive measurements of endothelial function predict future adverse cardiovascular events, but offer limited opportunities for mechanistic insights into phenotypic observations. Subcutaneous adipose arterioles, accessible through minimally invasive methods, provide an opportunity for complimentary mechanistic studies. Limited data relating subcutaneous arteriolar endothelial function, cardiovascular risk factors, and noninvasive measurements of endothelial function currently exist.

METHODS

Forty-four subjects underwent noninvasive studies of endothelial function (brachial reactivity (flow-mediated dilation (FMD) and digital pulse arterial tonometry (PAT)) and measurements of endothelial-dependent vasodilation of gluteal subcutaneous arterioles to acetylcholine. Arteriolar endothelial function was measured (i) percent vasodilation to maximal acetylcholine dose (10(-5) mol/l) and (ii) total area under the curve (AUC) for the entire acetylcholine dose-response curve (total AUC-acetylcholine (Ach), doses 10(-10)-10(-5) mol/l).

RESULTS

Acetylcholine responses were almost completely nitric oxide (NO) dependent. Total AUC-Ach predicted FMD and PAT, but maximal acetylcholine vasodilation was not associated with these measures. A history of hypertension, diabetes, smoking, and low-density lipoprotein cholesterol levels were independent predictors of total AUC-Ach. In regression models, total AUC-Ach independently predicted FMD.

CONCLUSIONS

Acetylcholine vasodilator responses in human gluteal subcutaneous arterioles are NO synthase dependent and correlate with cardiac risk factors and in vivo measures of endothelial function. These data suggest subcutaneous arterioles offer an opportunity for translational studies of mechanisms of modulating NO bioavailability relevant to in vivo endothelial function measures.

Acute exposure to low glucose rapidly induces endothelial dysfunction and mitochondrial oxidative stress: role for AMP kinase

OBJECTIVE

Hypoglycemia is associated with increased mortality. The reasons for this remain unclear, and the effects of low glucose exposure on vascular endothelial function remain largely unknown. We endeavored to determine the effects of low glucose on endothelial cells and intact human arterioles.

METHODS AND RESULTS

We exposed human umbilical vein endothelial cells to low glucose conditions in a clinically relevant range (40-70 mg/dL) and found rapid and marked reductions in nitric oxide (NO) bioavailability (P<0.001). This was associated with concomitantly increased mitochondrial superoxide production (P<0.001) and NO-dependent mitochondrial hyperpolarization (P<0.001). Reduced NO bioavailability was rapid and attributable to reduced endothelial nitric oxide synthase activity and destruction of NO. Low glucose rapidly activated AMP kinase, but physiological activation failed to restore NO bioavailability. Pharmacological AMP kinase activation led to phosphorylation of endothelial nitric oxide synthase's Ser633 activation site, reversing the adverse effects of low glucose. This protective effect was prevented by L-NG-Nitroarginine methyl ester. Intact human arterioles exposed to low glucose demonstrated marked endothelial dysfunction, which was prevented by either metformin or TEMPOL.

CONCLUSION

Our data suggest that moderate low glucose exposure rapidly impairs NO bioavailability and endothelial function in the human endothelium and that pharmacological AMP kinase activation inhibit this effect in an NO-dependent manner.

Establishment of a porcine model for lobar lung auto-transplantation

OBJECTIVE

The aim of this study was to develop a porcine model of left single lung auto-transplantation.

METHODS

Eighteen 50-kg male domestic pigs underwent left pneumonectomy and lobar lung auto-transplantation (left lower lobe). Each animal was allocated to a perfusion protocol during surgery: group I, cold saline (n = 6); group II, cold heparin (n = 6); and group III, cold Euro-Collins (n = 6). We measured changes of partial pressure of oxygen in pulmonary vein blood (PvO(2)), partial pressure of carbon dioxide in pulmonary vein blood (PvCO(2)), lung compliance, and mean pulmonary artery pressure.

RESULTS

The postoperative survival rate was 100%. PvO(2), PvCO(2), mean pulmonary artery pressure, and lung compliance of the left lower lobe showed a significant difference between the saline and the heparin groups or the Euro-Collins group (P < .05), whereas there was no significant difference between the heparin and the Euro-Collins groups.

CONCLUSION

Compared with other species, humans and pigs show remarkable anatomical and physiological similarity. It is useful experimental animal model to evaluate pulmonary function and grafting protocols following lobar lung transplantation.

Pretreatment with near-infrared light via light-emitting diode provides added benefit against rotenone- and MPP+-induced neurotoxicity

Parkinson's disease (PD) is a movement disorder caused by the loss of dopaminergic neurons in the substantia nigra pars compacta, leading to nigrostriatal degeneration. The inhibition of mitochondrial respiratory chain complex I and oxidative stress-induced damage have been implicated in the pathogenesis of PD. The present study used these specific mitochondrial complex I inhibitors (rotenone and 1-methyl-4-phenylpyridinium or MPP(+)) on striatal and cortical neurons in culture. The goal was to test our hypothesis that pretreatment with near-infrared light (NIR) via light-emitting diode (LED) had a greater beneficial effect on primary neurons grown in media with rotenone or MPP(+) than those with or without LED treatment during exposure to poisons. Striatal and visual cortical neurons from newborn rats were cultured in a media with or without 200 nM of rotenone or 250 microM of MPP(+) for 48 h. They were treated with NIR-LED twice a day before, during, and both before and during the exposure to the poison. Results indicate that pretreatment with NIR-LED significantly suppressed rotenone- or MPP(+)-induced apoptosis in both striatal and cortical neurons (P<0.001), and that pretreatment plus LED treatment during neurotoxin exposure was significantly better than LED treatment alone during exposure to neurotoxins. In addition, MPP(+) induced a decrease in neuronal ATP levels (to 48% of control level) that was reversed significantly to 70% of control by NIR-LED pretreatment. These data suggest that LED pretreatment is an effective adjunct preventative therapy in rescuing neurons from neurotoxins linked to PD.

A heat shock protein 90 binding domain in endothelial nitric-oxide synthase influences enzyme function

Previous reports suggest heat shock protein 90 (hsp90) associates with endothelial nitric-oxide synthase (eNOS) to increase nitric oxide (*NO) generation. Ansamycin inhibition of chaperone-dependent activity increases eNOS generation of superoxide anion (O(2)(*)) upon enzyme activation. In the present study we identify where hsp90 binds to eNOS using overlapping decoy peptides based on the amino acid (aa) sequence of eNOS (291-420). B1, B2, and B3 peptides inhibited hsp90 association with eNOS in cell lysates from proliferating bovine aortic endothelial cells. B2 (aa 301-320), common to both B1 and B3, decreased stimulated *NO production and hsp90 association in bovine aortic endothelial cells. The B2/B3 peptide was redesigned to TSB2 that includes a TAT protein transduction domain and shortened to 14 aa. TSB2 impaired vasodilation of isolated facialis arteries in vitro and in vivo and increased eNOS-dependent O(2)(*) generation in native endothelial cells on mouse aortas, whereas a control peptide, TSB(Ctr), which has the four glutamic acids in TSB2 substituted with alanine, showed no such effects. Site-directed mutagenesis of eNOS at 310, 314, 318, and 323 Glu to Ala yields an eNOS mutant that exhibited reduced hsp90 association and generated O(2)(*) rather than *NO upon activation. Together, these data demonstrate that hsp90 associates with eNOS at aa 310-323. Moreover, a decoy peptide based on this sequence is sufficient to displace hsp90 from eNOS and uncouple eNOS activity from *NO generation. Thus, Glu-310, Glu-314, Glu-318, and Glu-323 in eNOS, although each does not do much by itself, synergistically they increase "cooperativity" in the association step that is critical for maintaining hsp90-eNOS interactions and promoting coupled eNOS activity. Such chaperone-dependent signaling may play an important role in modulating the balance of *NO and O(2)(*) generation from eNOS and, therefore, vascular function.

Ulinastatin attenuates lung ischemia-reperfusion injury in rats by inhibiting tumor necrosis factor alpha

Ischemia-reperfusion (I/R) injury may influence graft function following transplantation. Ulinastatin, a urinary trypsin inhibitor has been shown to attenuate I/R injury in various organs such as intestine, heart, and kidney in animals. The present experiment was designed to evaluate the effect of pretreatment with ulinastatin on I/R-induced lung injury.

METHODS

After establishing a constant left lung warm ischemia-reperfusion model in rats, 45 animals were randomly divided into three experimental groups: sham group (n = 15), IR group (n = 15), and ulinastatin (5000 U/kg pre-ischemia) + IR group (n = 15). The lung injury was evaluated by tissue myeloperoxidase activity, with simultaneous estimation of the serum concentration of TNFalpha.

RESULTS

The ulinastatin-pretreated animals exhibited markedly decreased lung tissue myeloperoxidase activity (P < .05). Blood gas analysis demonstrated, that the treated animals had significantly ameliorated pulmonary oxygenation (P < .05). The serum concentration of TNF-alpha in the ulinastatin-pretreated group was markedly decreased compared with that of the I/R group (P < .05).

CONCLUSIONS

Ulinastatin attenuated I/R-induced lung injury. This function is partly related to the capacity of the agent to inhibit myeloperoxidase activity in lung tissue and decrease systemic expression to TNF-alpha.

[Surgical management of severe hemorrhage and retroperitoneal perforation after endoscopic sphincterotomy]

From 1990 to 1993, 5 patients with severe hemorrhage and retroperitoneal perforation following endoscopic sphincterotomy (EST) were surgically treated. Two patients with hemorrhage and one with perforation survived. The remaining two died of hemorrhage plus perforation. Early diagnosis and surgical intervention was very important to lower the mortality, especially in those with common bile duct stones retention, acute pancreatitis, or cholangitis. For patients with late stage perforation or recurrent hemorrhage, palliative procedure aimed at isolating the EST incision from the digestion of bile and pancreatic juice should be performed.

Hemagglutinins in fungus extracts and their blood group specificity

A total of 833 fungi harvested from 1977 to 1994 were tested and 422 extracts (47.8%) produced hemagglutination of human red cells. The lectins in fungus extracts which showed blood-group-specific or related reactions were partially purified by ammonium sulfate precipitation and gel filtration on a Sephadex G-100 column. Anti-H-like agglutinins were found in extracts of Pleurocybella porrigens, Naematoloma sublateritium and Pholiota squarrosa. These extracts agglutinated strongly with human group O red cells and rather weakly with A and B cells. Anti-A agglutinins were found in extracts of Hohenbuehelia serotina, Paxillus panuoides, Melanoleuca melaleuca and Hygrophorus capreolarius. The extract of Clavulinopsis fusiformis contained anti-B agglutinin. The ABH reactivities of the extracts were cofirmed by an agglutination inhibition test with ABH secretor saliva and blood group substances from human gastric linings and by the destruction of inhibiting activity using blood-group-specific decomposing enzymes. L-Fucose was the most active inhibiting monosacharide of anti-H-like agglutinins. The reaction of anti-A agglutinins was strongly inhibited by N-acetyl-D-galactosamine. D-Galactose and raffinose and melibiose which contain alpha-galactosyl residues were potent inhibitors of C. fusiformis agglutinin.

Computer 3-dimensional reconstruction of intraglandular lymph vessels and ductal systems of the human submandibular gland

Computer three-dimensional reconstruction of serial sections is currently an active area of research. In this paper we combine computer graphics, image processing and biomedical techniques to reconstruct a stereo model of intraglandular lymphatic vessels, veins, arteries and ducts from serial microsections of the human submandibular gland.