Increased plasma levels of the mature and intermediate forms of adrenomedullin in obesity

Adrenomedullin improved endothelial dysfunction via receptor-Akt pathway in rats with obesity-related hypertension

Obesity-related hypertension (OH) is accompanied by obvious endothelial dysfunction, which contributes to increased peripheral vascular resistance and hypertension. Adrenomedullin (ADM), a multifunctional active peptide, is elevated in obese humans. The OH rats induced by high fat diet (HFD) for 28 weeks and the human umbilical vein endothelial cells (HUVECs)-treated by palmitic acid (PA) were used to investigate the effects of ADM on endothelial dysfunction and the underlying mechanisms. Vascular reactivity was assessed using mesenteric arteriole rings, and the protein expression levels were examined by Western blot analysis. Compared with the control rats, OH rats exhibited hypertension and endothelial dysfunction, along with reduced eNOS protein expression and Akt activation, and increased protein expression of proinflammatory cytokines and ROS levels. Four-week ADM administration improved hypertension and endothelial function, increased eNOS protein expression and Akt activation, and attenuated endothelial inflammation and oxidative stress in OH rats. In vitro experiment, the antagonism of ADM receptors with ADM22-52 and the suppression of Akt signaling with A6730 significantly blocked ADM-caused increase of NO content and activation of eNOS and Akt, and inhibited the anti-inflammatory and anti-oxidant effect of ADM in PA-stimulated HUVECs. These data indicate that endothelial dysfunction in OH rats is partially attributable to the decreased NO level, and the increased inflammation and oxidative stress. ADM improves endothelial function and exerts hypotensive effect depending on the increase of NO, and its anti-inflammatory and anti-oxidant effect via receptor-Akt pathway.

Circulating adipose tissue proteins involved in atrial fibrillation: An explorative scoping review

Obesity increases the risk of atrial fibrillation (AF), potentially through proteins secreted by adipose tissue (AT) that affect atrial electrical and structural remodeling. We aim to give a comprehensive overview of circulating AT proteins involved in inflammation and fibrosis, that are associated with prevalent AF (paroxysmal or persistent) and the risk on developing new-onset AF. These include adipokines, defined as proteins enriched in AT as adiponectin, but also proteins less specific to AT. We systematically performed an explorative search for studies reporting associations between proteins secreted from cells residing in the AT and AF, and additionally assessed the effect of obesity on these proteins by a secondary search. The AT proteins involved in inflammation were mostly increased in patients with prevalent and new-onset AF, and with obesity, while the AT enriched adipokines were mostly not associated with AF. This review provides insight into circulating adipose tissue proteins involved in AF substrate formation.

Adrenomedullin Improves Hypertension and Vascular Remodeling partly through the Receptor-Mediated AMPK Pathway in Rats with Obesity-Related Hypertension

Adrenomedullin (ADM) is a novel cardiovascular peptide with anti-inflammatory and antioxidant properties. Chronic inflammation, oxidative stress and calcification play pivotal roles in the pathogenesis of vascular dysfunction in obesity-related hypertension (OH). Our study aimed to explore the effects of ADM on the vascular inflammation, oxidative stress and calcification in rats with OH. Eight-week-old Sprague Dawley male rats were fed with either a Control diet or a high fat diet (HFD) for 28 weeks. Next, the OH rats were randomly subdivided into two groups as follows: (1) HFD control group, and (2) HFD with ADM. A 4-week treatment with ADM (7.2 μg/kg/day, ip) not only improved hypertension and vascular remodeling, but also inhibited vascular inflammation, oxidative stress and calcification in aorta of rats with OH. In vitro experiments, ADM (10 nM) in A7r5 cells (rat thoracic aorta smooth muscle cells) attenuated palmitic acid (PA, 200 μM) or angiotensin II (Ang II, 10 nM) alone or their combination treatment-induced inflammation, oxidative stress and calcification, which were effectively inhibited by the ADM receptor antagonist ADM22-52 and AMP-activated protein kinase (AMPK) inhibitor Compound C, respectively. Moreover, ADM treatment significantly inhibited Ang II type 1 receptor (AT1R) protein expression in aorta of rats with OH or in PA-treated A7r5 cells. ADM improved hypertension, vascular remodeling and arterial stiffness, and attenuated inflammation, oxidative stress and calcification in OH state partially via receptor-mediated AMPK pathway. The results also raise the possibility that ADM will be considered for improving hypertension and vascular damage in patients with OH.

Adrenomedullin in paraventricular nucleus attenuates adipose afferent reflex and sympathoexcitation via receptors mediated nitric oxide-gamma-aminobutyric acid A type receptor pathway in rats with obesity-related hypertension

BACKGROUND

Hypothalamic paraventricular nucleus (PVN) is an important central site for the control of the adipose afferent reflex (AAR) that increases sympathetic outflow and blood pressure in obesity-related hypertension (OH).

METHOD

In this study, we investigated the effects of nitric oxide (NO) and cardiovascular bioactive polypeptide adrenomedullin (ADM) in the PVN on AAR and sympathetic nerve activity (SNA) in OH rats induced by a high-fat diet.

RESULTS

The results showed that ADM, total neuronal NO synthase (nNOS) and phosphorylated-nNOS protein expression levels in the PVN of the OH rats were down-regulated compared to the control rats. The enhanced AAR in OH rats was attenuated by PVN acute application of NO donor sodium nitroprusside (SNP), but was strengthened by the nNOS inhibitor nNOS-I, guanylyl cyclase inhibitor (1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one, ODQ) and gamma-aminobutyric acid A type receptor (GABAA) antagonist Bicuculline. Moreover, PVN ADM microinjection not only decreased basal SNA but also attenuated the enhanced AAR in OH rats, which were effectively inhibited by ADM receptor antagonist ADM22-52, nNOS-I, ODQ or Bicuculline pretreatment. Bilateral PVN acute microinjection of ADM also caused greater increases in NO and cyclic guanosine monophosphate (cGMP) levels, and nNOS phosphorylation. Adeno-associated virus vectors encoding ADM (AAV-ADM) transfection in the PVN of OH rats not only decreased the elevated AAR, basal SNA and blood pressure (BP), but also increased the expression and activation of nNOS. Furthermore, AAV-ADM transfection improved vascular remodeling in OH rats.

CONCLUSION

Taken together, our data highlight the roles of ADM in improving sympathetic overactivation, enhanced AAR and hypertension, and its related mechanisms associated with receptors mediated NO-cGMP-GABAA pathway in OH condition.

Associations of Plasma Bioactive Adrenomedullin Levels with Cardiovascular Risk Factors in BRCA1/2 Mutation Carriers

Background Cardiovascular disease (CVD) is an important cause of morbidity and mortality in breast cancer survivors. Effective screening modalities to identify CVD risk are lacking in this population. Adrenomedullin (ADM) has been suggested as a biomarker for subclinical cardiac dysfunction in the general population. Levels of ADM have been proven to be responsive to lifestyle changes that lead to improved cardiovascular health. As BRCA1/2 mutation carriers are deemed to be at an increased risk for CVD, the aim of this study was to examine plasma ADM levels in a cohort of BRCA mutation carriers and to assess their association with cardiovascular risk factors.

Methods Plasma ADM concentrations were measured in 292 female BRCA1/2 mutation carriers with and without a history of breast cancer. Subjects were classified into high versus low ADM levels based on the median ADM level in the entire cohort (13.8 pg/mL). Logistic regression models were used to estimate the odds ratios (OR) of having elevated ADM levels by several cardiovascular risk factors.

Results Of all women (median age: 43 years), 57.5% had a previous diagnosis of breast cancer. The median time between diagnosis and study entry was three years (range: 0 – 32 years). Women presenting with metabolic syndrome had 22-fold increased odds of having elevated ADM levels (p < 0.001). Elevated ADM levels were associated with lower cardiorespiratory fitness (OR = 0.88, p < 0.001) and several parameters of obesity (p < 0.001). ADM levels were higher in women who have ever smoked (OR = 1.72, p = 0.02). ADM levels were not associated with a previous diagnosis of breast cancer (p = 0.28).

Conclusions This is the first study in BRCA mutation carriers that has linked circulating ADM levels to traditional cardiovascular risk factors. The long-term clinical implications of these findings are yet to be determined.

Adrenomedullin ameliorates palmitic acid-induced insulin resistance through PI3K/Akt pathway in adipocytes

AIMS

White adipose tissue (WAT) dysfunction has been associated with adipose tissue low-grade inflammation and oxidative stress leading to insulin resistance (IR). Adrenomedullin (ADM), an endogenous active peptide considered as an adipokine, is associated with adipocytes function.

METHODS

We evaluated the protective effects of ADM against IR in 3T3-L1 adipocytes treated by palmitic acid (PA) and in visceral white adipose tissue (vWAT) of obese rats fed with high-fat diet.

RESULTS

We found that endogenous protein expressions of ADM and its receptor in PA-treated adipocytes were markedly increased. PA significantly induced impaired insulin signaling by affecting phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt) axis and glucose transporter-4 (GLUT-4) levels, whereas ADM pretreatment enhanced insulin signaling PI3K/Akt and GLUT-4 membrane protein levels, decreased pro-inflammatory cytokines tumor necrosis factor α (TNFα), interleukin-1β (IL-1β) and IL-6 levels, and improved oxidative stress accompanied with reduced reactive oxygen species (ROS) levels and increased anti-oxidant enzymes manganese superoxide dismutase 2 (SOD2), glutathione peroxidase (GPx1) and catalase (CAT) protein expressions. Furthermore, ADM treatment not only improved IR in obese rats, but also effectively restored insulin signaling, and reduced inflammation and oxidative stress in vWAT of obese rats.

CONCLUSIONS

This study demonstrates a prevention potential of ADM against obesity-related metabolic disorders, due to its protective effects against IR, inflammation and oxidative stress in adipocytes.

Plasma adrenomedullin level and year-by-year variability of body mass index in the general population

Plasma levels of the hypotensive peptides of adrenomedullin and atrial and B-type natriuretic peptides (AM, ANP, BNP) are possible biomarkers for cardiovascular diseases. Increased variability of body mass index (BMI) over a certain period of time has been reported to be associated with cardiovascular morbidity or mortality. The aim of this study is to examine clinical significance of those hypotensive peptides as biomarkers by analyzing the relationship between plasma levels of the peptides and year-by-year variability of BMI in the general population without overt cardiovascular diseases. The subjects were 427 local residents (141 males and 286 females) attending their annual health check-up, who had been examined at least 5 times over the preceding period of 10 years. They were divided into two groups of low or high variability by the median of coefficient of variation (CV) of BMI values for each gender. Plasma AM levels of those with high year-by-year variability of BMI were significantly increased, as compared to the group with low variability, in both genders; meanwhile, such a difference was not noted in plasma levels of the natriuretic peptides. No significant differences were found in the basal parameters, which could affect plasma AM level, such as age, BMI, blood pressure or serum creatinine, between two groups. In conclusion, increase in plasma AM was associated with high year-by-year variability of BMI in the general population without overt heart disease. This relationship between the two suggests that increased plasma AM level is a cardiovascular risk marker.

Targeting Adrenomedullin in Oncology: A Feasible Strategy With Potential as Much More Than an Alternative Anti-Angiogenic Therapy

The development, maintenance and metastasis of solid tumors are highly dependent on the formation of blood and lymphatic vessels from pre-existing ones through a series of processes that are respectively known as angiogenesis and lymphangiogenesis. Both are mediated by specific growth-stimulating molecules, such as the vascular endothelial growth factor (VEGF) and adrenomedullin (AM), secreted by diverse cell types which involve not only the cancerogenic ones, but also those constituting the tumor stroma (i.e., macrophages, pericytes, fibroblasts, and endothelial cells). In this sense, anti-angiogenic therapy represents a clinically-validated strategy in oncology. Current therapeutic approaches are mainly based on VEGF-targeting agents, which, unfortunately, are usually limited by toxicity and/or tumor-acquired resistance. AM is a ubiquitous peptide hormone mainly secreted in the endothelium with an important involvement in blood vessel development and cardiovascular homeostasis. In this review, we will introduce the state-of-the-art in terms of AM physiology, while putting a special focus on its pro-tumorigenic role, and discuss its potential as a therapeutic target in oncology. A large amount of research has evidenced AM overexpression in a vast majority of solid tumors and a correlation between AM levels and disease stage, progression and/or vascular density has been observed. The analysis presented here indicates that the involvement of AM in the pathogenesis of cancer arises from: 1) direct promotion of cell proliferation and survival; 2) increased vascularization and the subsequent supply of nutrients and oxygen to the tumor; 3) and/or alteration of the cell phenotype into a more aggressive one. Furthermore, we have performed a deep scrutiny of the pathophysiological prominence of each of the AM receptors (AM₁ and AM₂) in different cancers, highlighting their differential locations and functions, as well as regulatory mechanisms. From the therapeutic point of view, we summarize here an exhaustive series of preclinical studies showing a reduction of tumor angiogenesis, metastasis and growth following treatment with AM-neutralizing antibodies, AM receptor antagonists, or AM receptor interference. Anti-AM therapy is a promising strategy to be explored in oncology, not only as an anti-angiogenic alternative in the context of acquired resistance to VEGF treatment, but also as a potential anti-metastatic approach.

Midregional proadrenomedullin predicts reduced blood pressure and glucose elevation over time despite enhanced progression of obesity markers

OBJECTIVES

Elevated plasma levels of the vasodilating hormone adrenomedullin (ADM) predict cardiovascular disease and have been associated with hypertension and obesity. We aimed to examine the independent relationship between ADM and the progression of major cardiometabolic risk factors during long-term follow-up.

METHODS

We studied midregional pro-ADM (MR-proADM) in fasting plasma in 3298 participants from the population-based Malmö Diet and Cancer Study - Cardiovascular Cohort, re-examined after 17 years of follow-up and related baseline MR-proADM to cardiometabolic risk factors cross-sectionally and longitudinally.

RESULTS

At baseline, after full adjustment, each SD increment of MR-proADM was independently related to (beta ± standard error, P value) higher SBP (0.956 ± 0.319 mmHg, P = 0.003), BMI (0.912 ± 0.061 kg/m, P = 1.42 × 10), waist (2.28 ± 0.158 cm, P = 8.46 × 10) and fasting blood glucose (0.046 ± 0.018 mmol/l, P = 0.01). After full adjustment, including the baseline level of the risk factor whose degree of progression was studied, each SD increment of MR-proADM predicted significantly reduced progression of SBP (-1.170 ± 0.337 mmHg, P = 0.001) and fasting blood glucose (-0.055 ± 0.023 mmol/l, P = 0.015), but greater increase of BMI (0.101 ± 0.051 kg/m, P = 0.047) and waist (0.600 ± 0.144 cm, P = 3.1 × 10).

CONCLUSION

Despite cross-sectional associations with higher levels of blood pressure and glucose, high levels of MR-proADM predict a slower progression of blood pressure and glycemia during long-term follow-up. Conversely, the cross-sectional associations with higher levels of MR-proADM and obesity were paralleled by a faster progression of obesity markers over time. These results may be important for assessment of long-term effects of therapies modulating levels of ADM.

Sex differences in gene expression related to antipsychotic induced weight gain

Antipsychotics are crucial for the treatment of schizophrenia and contribute to weight gain in psychosis, particularly during early phases. Antipsychotic Induced Weight Gain (AIWG) might contribute to reduce the quality of life, drug compliance and to increase mortality. To characterize sex differences of gene expression related to AIWG, we sequenced total mRNA from blood samples of schizophrenia patients, before and after 3 months of antipsychotic-treatment. We analyzed schizophrenia patients according to their sex (38 males and 39 females) and their BMI increase after medication, characterizing the differential gene expression before and after medication. Individuals in each group were categorized in patients who gain weight and those whose do not gain weight. The “weight gain” groups included patients with an increase of body mass index (BMI) > 1.0 points (27 males and 23 females with a median BMI increase of 2.68 and 2.32 respectively). The “no weight gain” groups included patients with a change of BMI between < 1.0 and > -1.0 points (11 males and 16 females with a median BMI increase of 0.21 and 0.16 respectively). The males had 331 genes with significant differential expression in the weight gain group and 24 genes in the no weight gain group. The females had 119 genes with significant differential expression in the weight gain group and 75 genes in the no weight gain group. Both weight gain groups were significantly enriched with “obesity” genes (Fisher; p = 1.1E-09 and p = 0.0001 respectively), according to the Gene Reference into Function (GeneRIF) database.In conclusion, we characterized genes with differential expression associated to AIWG that are specific to males, to females and common to both sexes. These genes are good candidates to depict the biological processes involved in AIWG and provide additional evidence of the genetic links between weight gain and the immune system.

Altered gene expression in antipsychotic-induced weight gain

Antipsychotic drugs are one of the largest types of prescribed drugs. However, antipsychotic-induced weight gain (AIWG) is a major problem for the patients. AIWG increases cardiovascular and cerebrovascular morbidity and mortality, and reduces quality of life and drug compliance. To characterize changes in gene expression related to AIWG, we sequenced total messenger RNA from the blood samples of two groups of schizophrenia patients before and after 3 months of treatment with antipsychotics. The "weight gain" group was defined by an increase of body mass index (BMI) >1.5 points (18 patients; median BMI increase = 2.69) and the "no weight gain" group was defined by a change of BMI between <1.0 and >-1.0 points (18 patients; median BMI increase = 0.26). We found 115 genes with significant differential expression in the weight gain group before and after medication and 156 in the no weight gain group before and after medication. The weight gain group was significantly enriched with genes related to "obesity" and "BMI" (Fisher; p = 0.0002 and 0.01, respectively) according to the Gene Reference into Function (GeneRIF) database. In the no weight gain group, the enrichment was much smaller (Fisher; p = 0.02 and 0.79). This study is a first step toward detecting genetic factors that cause AIWG and to generating prediction tests in future studies with larger data sets.

RAMP3 deficiency enhances postmenopausal obesity and metabolic disorders

There is a marked increase in the incidence of visceral adiposity and insulin resistance among women following menopause. Adrenomedullin (AM) is an endogenous peptide first identified as a vasodilator, but now known to exert a variety of physiological effects. RAMP3 is a receptor activity-modifying protein that binds to the AM receptor (calcitonin receptor-like receptor). As expression of both AM and RAMP3 is reportedly activated by estrogen, we hypothesized that RAMP3 is crucially involved in the pathophysiology of postmenopausal obesity. To test this idea, we compared the effects of ovariectomy (OVX) and a high-fat diet for 10 weeks (a model of postmenopausal obesity) between RAMP3 knockout (RAMP3-/-) and wild-type mice. RAMP3-/- OVX mice exhibited greater obesity and adipose tissue weight gain as compared to wild-type OVX mice. RAMP3-/- OVX mice also exhibited higher serum insulin levels. In periuterine WAT from RAMP3-/- OVX mice, expression of lipolysis-related factors was lower and expression of inflammation-related factors was higher than in wild-type OVX mice. Hepatic steatosis was also exacerbated in RAMP3-/- OVX. Notably, expression of the membrane-type estrogen receptor GPR30 was downregulated in periuterine WAT from RAMP3-/- OVX mice. These findings raise the possibility that a GPR30-RAMP3 interaction is involved in the pathophysiology of postmenopausal obesity and suggest RAMP3 plays a key role in the regulation of energy metabolism and exerts a hepatoprotective effect in this model of postmenopausal obesity. RAMP3 may thus be a useful therapeutic target for treatment of postmenopausal obesity and metabolic disorders.

Five-week yin yoga-based interventions decreased plasma adrenomedullin and increased psychological health in stressed adults: A randomized controlled trial

Background

Non-communicable diseases (NCDs, e.g. cardiovascular disease) are responsible for high rates of morbidity and the majority of premature deaths worldwide. It is necessary to develop preventative interventions that can reduce the associated risk factors of NCDs. Researchers have found that the biomarker adrenomedullin (ADM) becomes elevated years before the onset of NCDs and might play an important role in their development. ADM has also been linked to psychological problems such as stress, anxiety, and depression, which are known risk factors of NCDs. In this randomized controlled trial, we examined whether participating in a five-week yoga intervention reduces ADM and increases psychological health in middle-aged adults who self-report as moderately to highly stressed, but who otherwise exhibit no physical complaints.

Methods

One hundred and five adults (78% women; mean age = 53.5, SD = 6.7) were randomly assigned to (1) a five-week Yin yoga intervention, (2) a five-week intervention combining Yin yoga with psychoeducation and mindfulness practice (called the YOMI program), or (3) a control group who did not practice yoga or mindfulness for five weeks.

Results

Compared to the control group, we observed significantly greater pre-post reductions in plasma ADM levels (p < .001), anxiety (p ≤ .002), and sleep problems (p ≤ .003) in both intervention groups. Furthermore, the YOMI group exclusively showed significantly greater pre-post reductions in stress (p = .012) and depression (p = .021) compared to the control group. Significant correlations (p < .05) were found between pre-post reductions in ADM and anxiety symptoms (p = .02) and depression (p = .04) in the entire sample.

Conclusion

The five-week Yin yoga-based interventions appeared to reduce both the physiological and psychological risk factors known to be associated with NCDs. The study suggests that incorporating Yin yoga could be an easy and low-cost method of limiting the negative health effects associated with high stress.

Trial registration

ClinicalTrials.gov NCT03428542

Plasma adrenomedullin level in children with obesity: relationship to left ventricular function

BACKGROUND

Obese children are at increased risk for abnormal cardiac structure and function. Little is known about adrenomedullin (AM), a cytokine produced in various organs and tissues, as a biomarker of cardiac hypertrophy in obese children. This study aimed to assess the plasma AM levels in a cohort of obese children and its relationship to left ventricular (LV) functions.

METHODS

The study included 60 obese children and 60 non-obese children matched for age and gender as control group. Blood pressure, serum lipid profile, fasting glucose, insulin and plasma AM and the homeostatic model assessment of insulin resistance (HOMA-IR) were measured. Cardiac dimensions and LV functions were assessed using conventional echocardiography.

RESULTS

Compared to control subjects, obese children had higher blood pressure (P = 0.01), insulin (P = 0.001), HOMA-IR (P = 0.001), and AM (P = 0.001). Moreover, obese children had higher LV mass index (LVMI) (P = 0.001), indicating LV hypertrophy; prolonged isovolumic relaxation times (P = 0.01), prolonged mitral deceleration time (DcT) (P = 0.01) and reduced ratio of mitral E-to-mitral A-wave peak velocity (P = 0.01), indicating LV diastolic dysfunction. Laboratory abnormalities were only present in children with LV hypertrophy. In multivariate analysis in obese children with LV hypertrophy, AM levels were positively correlated with LVMI [odds ratio (OR) 1.14, 95% confidence interval (Cl) 1.08-1.13, P = 0.0001] and mitral DcT (OR 2.25, 95% CI 1.15-2.05, P = 0.01) in the presence of higher blood pressure and HOMA-IR. A cut-off value of AM at 52 pg/mL could differentiate obese children with and without left ventricular hypertrophy at a sensitivity of 94.32% and specificity of 92.45%.

CONCLUSIONS

Plasma AM levels may be elevated in obese children particularly those with LV hypertrophy and is correlated with higher blood pressure and insulin resistance. Measurement of plasma AM levels in obese children may help to identify those at high risk of developing LV hypertrophy and dysfunction.

Immunologic and endocrine functions of adipose tissue: implications for kidney disease

Excess adiposity can induce adverse sequelae in multiple cell types and organ systems. The transition from the lean to the obese state is characterized by fundamental cellular changes at the level of the adipocyte. These changes affect the local microenvironment within the respective adipose tissue but can also affect nonadipose systems. Adipocytes within fat pads respond to chronic nutrient excess through hyperplasia or hypertrophy, which can differentially affect interorgan crosstalk between various adipose depots and other organs. This crosstalk is dependent on the unique ability of the adipocyte to coordinate metabolic adjustments throughout the body and to integrate responses to maintain metabolic homeostasis. These actions occur through the release of free fatty acids and metabolites during times of energy need - a process that is altered in the obese state. In addition, adipocytes release a wide array of signalling molecules, such as sphingolipids, as well as inflammatory and hormonal factors (adipokines) that are critical for interorgan crosstalk. The interactions of adipose tissue with the kidney - referred to as the adipo-renal axis - are important for normal kidney function as well as the response of the kidney to injury. Here, we discuss the mechanistic basis of this interorgan crosstalk, which clearly has great therapeutic potential given the increasing rates of chronic kidney disease secondary to obesity and type 2 diabetes mellitus.

Intermedin attenuates high-glucose exacerbated simulated hypoxia/reoxygenation injury in H9c2 cardiomyocytes via ERK1/2 signaling

Objective:

This study investigated whether and how intermedin (IMD) exerted a protective effect against simulated hypoxia/reoxygenation (H/R) injury in high-glucose-treated H9c2 cells.

Methods:

Cellular viability was assessed via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Oxidative stress was determined by malondialdehyde and superoxide dismutase content in the culture medium supernatant. Flow cytometry with Annexin V/propidium iodide staining was used to detect the cardiomyocyte apoptosis rate. The protein expression of Bax, Bcl-2, caspase-3, and ERK1/2 was determined by western blot.

Results:

IMD administration to H9c2 cells during H/R injury decreased oxidative stress product generation and inhibited apoptosis ( P < 0.05 or P < 0.01) while these effects were blocked by the ERK1/2 inhibitor ( P < 0.05 or P < 0.01). Through the application of a specific ERK1/2 inhibitor, it was demonstrated that IMD mitigates high-glucose-induced oxidative stress and apoptosis via ERK1/2 signaling.

Conclusion:

Intermedin may be a novel therapeutic agent for mitigating diabetic cardiovascular injury in the clinical setting.

Prenatal phthalate exposure and altered patterns of DNA methylation in cord blood

Epigenetic changes such as DNA methylation may be a molecular mechanism through which environmental exposures affect health. Phthalates are known endocrine disruptors with ubiquitous exposures in the general population including pregnant women, and they have been linked with a number of adverse health outcomes. We examined the association between in utero phthalate exposure and altered patterns of cord blood DNA methylation in 336 Mexican-American newborns. Concentrations of 11 phthalate metabolites were analyzed in maternal urine samples collected at 13 and 26 weeks gestation as a measure of fetal exposure. DNA methylation was assessed using the Infinium HumanMethylation 450K BeadChip adjusting for cord blood cell composition. To identify differentially methylated regions (DMRs) that may be more informative than individual CpG sites, we used two different approaches, DMRcate and comb-p. Regional assessment by both methods identified 27 distinct DMRs, the majority of which were in relation to multiple phthalate metabolites. Most of the significant DMRs (67%) were observed for later pregnancy (26 weeks gestation). Further, 51% of the significant DMRs were associated with the di-(2-ethylhexyl) phthalate metabolites. Five individual CpG sites were associated with phthalate metabolite concentrations after multiple comparisons adjustment (FDR), all showing hypermethylation. Genes with DMRs were involved in inflammatory response (IRAK4 and ESM1), cancer (BRCA1 and LASP1), endocrine function (CNPY1), and male fertility (IFT140, TESC, and PRDM8). These results on differential DNA methylation in newborns with prenatal phthalate exposure provide new insights and targets to explore mechanism of adverse effects of phthalates on human health. Environ. Mol. Mutagen. 58:398-410, 2017. © 2017 Wiley Periodicals, Inc.

Intermedin Restores Hyperhomocysteinemia-induced Macrophage Polarization and Improves Insulin Resistance in Mice

Hyperhomocysteinemia (HHcy) is a condition characterized by an abnormally high level of homocysteine, an inflammatory factor. This condition has been suggested to promote insulin resistance. To date, the underlying molecular mechanism remains largely unknown, and identifying novel therapeutic targets for HHcy-induced insulin resistance is of high priority. It is well known that intermedin (IMD), a calcitonin family peptide, exerts potent anti-inflammatory effects. In this study, the effects of IMD on HHcy-induced insulin resistance were investigated. Glucose tolerance and insulin tolerance tests were performed on mice treated with IMD by minipump implantation (318 ng/kg/h for 4 weeks) or adipocyte-specific IMD overexpression mice (Adipo-IMD transgenic mice). The expression of genes and proteins related to M1/M2 macrophages and endoplasmic reticulum stress (ERS) was evaluated in adipose tissues or cells. The expression of IMD was identified to be lower in the plasma and adipose tissues of HHcy mice. In both IMD treatment by minipump implantation and Adipo-IMD transgenic mice, IMD reversed HHcy-induced insulin resistance, as revealed by glucose tolerance and insulin tolerance tests. Further mechanistic study revealed that IMD reversed the Hcy-elevated ratio of M1/M2 macrophages by inhibiting AMP-activated protein kinase activity. Adipo-IMD transgenic mice displayed reduced ERS and lower inflammation in adipose tissues with HHcy. Soluble factors from Hcy-treated macrophages induced adipocyte ERS, which was reversed by IMD treatment. These findings revealed that IMD treatment restores the M1/M2 balance, inhibits chronic inflammation in adipose tissues, and improves systemic insulin sensitivity of HHcy mice.

Gender-related alterations in plasma adrenomedullin level and its correlation with body weight gain

Plasma levels of adrenomedullin (AM), a bioactive peptide produced in adipose tissue, have been shown to be higher in obese patients than in non-obese patients, but little is known about gender differences in plasma AM levels. The aims of this study were to clarify gender-related alterations in plasma AM levels and to examine the body weight (BW) gain-plasma AM relationship in the general population. We measured plasma AM levels of 346 local residents (62.0±8.9 years, mean±s.d.) in the Kiyotake area, Japan, who underwent a regular health check-up, by a specific fluorescence immunoassay. Plasma AM levels in the female residents were lower than that in the males, and multiple regression analysis revealed a possible gender difference in plasma AM. The AM levels were significantly correlated with BMI or waist circumference in women, but such a relationship was not seen in men. When the subjects were divided into two groups by results of a questionnaire about BW gain of 10 kg or more since the age of 20 years, the plasma AM level of women with BW gain ≧10 kg was significantly higher than that in those without BW gain, although no difference was noted between the men with and without BW gain. In conclusion, possible gender differences were noted in the plasma AM levels and in the BW gain-plasma AM relationship in the general population. The plasma AM levels in the female residents without BW gain seem partly attributable to the lower AM of women.

The influence of diabetes mellitus on midregional proadrenomedullin concentrations and prognostic value in heart failure outpatients

BACKGROUND

Diabetes mellitus (DM) is associated with an adverse outcome in heart failure (HF). Increased concentrations of midregional proadrenomedullin (MR-proADM) have been associated with DM and are predictors of mortality in HF patients. The aim of this study was to elucidate the impact of DM on MR-proADM concentrations and the prognostic value regarding all-cause mortality and hospitalization among HF patients.

METHODS AND RESULTS

We included 366 patients from an HF clinic; 69 (19%) had a history of DM and 40 (11%) had newly diagnosed DM (HbA1c ≥48 mmol/mol). The median MR-proADM concentration was unaffected by DM status (P = .20) but increased in HF patients with impaired renal function (P < .001). During a median follow-up of 55 months, 189 died, and 292 either died or were hospitalized. After adjustment for clinically relevant parameters, MR-proADM was associated with all-cause mortality (hazard ratio [HR] 1.3, 95% confidence interval [CI] 1.1-1.4; P = .01) and the combined end point of death and hospitalization (HR 1.2, 95% CI 1.1-1.4; P = .02) per 1 SD increment of ln-transformed variable. No interaction between DM and MR-proADM was found regarding mortality or hospitalization.

CONCLUSIONS

Diabetes status had no impact on MR-proADM concentrations or in the predictive ability of MR-proADM in HF patients.

Greater expression of inflammatory cytokines, adrenomedullin, and natriuretic peptide receptor-C in epicardial adipose tissue in coronary artery disease

BACKGROUND

Growing evidence suggests that the epicardial adipose tissue may have local interactions with coronary arteries. In addition, vasoactive peptides such as adrenomedullin and natriuretic peptide has an interaction with adipose tissue. In this study, we investigated the relationship between adipokines, adipocytokines, and vasoactive peptides expressed in epicardial adipose tissue and subcutaneous adipose tissue in patients with and without coronary artery disease (CAD).

METHODS

We studied 20 patients with CAD and 14 patients without CAD. We obtained blood samples and epicardial and subcutaneous adipose tissue at open-heart surgery. We measured serum cytokine levels and used real-time polymerase chain reaction (PCR) to measure mRNA levels of various molecules in epicardial and subcutaneous tissue and investigated the relation between mRNA levels and clinical parameters.

RESULTS

The mRNA levels of IL-6, IL-1beta, MCP-1, and TNF-alpha were significantly higher in epicardial adipose tissue than in subcutaneous adipose tissue. Interestingly, the mRNA levels of IL-6, IL-1beta, MCP-1, natriuretic peptide receptor-C (NPR-C), adrenomedullin, and leptin in epicardial adipose tissue were higher in patients with CAD than those without CAD. In contrast, mRNA levels of adiponectin, PPAR-gamma, and NPR-A were similar in the two groups. In subcutaneous tissue, mRNA expressions of IL-6, IL-1beta, MCP-1, NPR-C, adrenomedullin, and leptin were modestly higher in patients with CAD than in those without CAD. There were no differences in plasma cytokine levels between the two groups.

CONCLUSION

The mRNA levels of inflammatory cytokines, adipokines, neurohumoral factors and their receptors appear to be increased in epicardial adipose tissue independent of plasma levels of these molecules. Further studies are necessary to elucidate the pathophysiological role of these molecules in CAD.