Resistin increases monolayer permeability of human coronary artery endothelial cells

Beyond the barrier: the immune-inspired pathways of tumor extravasation

Extravasation is a fundamental step in the metastatic journey, where cancer cells exit the bloodstream and breach the endothelial cell barrier to infiltrate target tissues. The tactics cancer cells employ are sophisticated, closely reflecting those used by the immune system for tissue surveillance. Remarkably, tumor cells have been observed to form distinct associations or clusters with immune cells where neutrophils stand out as particularly crucial partners. These interactions are not accidental; they are critical for cancer cells to exploit the immune functions of neutrophils and successfully extravasate. In another strategy, tumor cells mimic the behavior and characteristics of immune cells. They release a suite of inflammatory mediators, which under normal circumstances, guide the processes of endothelium reshaping and facilitate the entry and movement of immune cells within tissues. In this review, we offer a new perspective on the tactics employed by cancer cells to extravasate and infiltrate target tissues. We delve into the myriad mechanisms that tumor cells borrow, adapt, and refine from the immune playbook. Video Abstract.

Role of Perturbated Hemostasis in MASLD and Its Correlation with Adipokines

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to rise, making it one of the most prevalent chronic liver disorders. MASLD encompasses a range of liver pathologies, from simple steatosis to metabolic dysfunction-associated steatohepatitis (MASH) with inflammation, hepatocyte damage, and fibrosis. Interestingly, the liver exhibits close intercommunication with fatty tissue. In fact, adipose tissue could contribute to the etiology and advancement of MASLD, acting as an endocrine organ that releases several hormones and cytokines, with the adipokines assuming a pivotal role. The levels of adipokines in the blood are altered in people with MASLD, and recent research has shed light on the crucial role played by adipokines in regulating energy expenditure, inflammation, and fibrosis in MASLD. However, MASLD disease is a multifaceted condition that affects various aspects of health beyond liver function, including its impact on hemostasis. The alterations in coagulation mechanisms and endothelial and platelet functions may play a role in the increased vulnerability and severity of MASLD. Therefore, more attention is being given to imbalanced adipokines as causative agents in causing disturbances in hemostasis in MASLD. Metabolic inflammation and hepatic injury are fundamental components of MASLD, and the interrelation between these biological components and the hemostasis pathway is delineated by reciprocal influences, as well as the induction of alterations. Adipokines have the potential to serve as the shared elements within this complex interrelationship. The objective of this review is to thoroughly examine the existing scientific knowledge on the impairment of hemostasis in MASLD and its connection with adipokines, with the aim of enhancing our comprehension of the disease.

Resistin secreted by porcine alveolar macrophages leads to endothelial cell dysfunction during Haemophilus parasuis infection

Haemophilus parasuis (H. parasuis) causes exudative inflammation, implying endothelial dysfunction during pathogen infection. However, so far, the molecular mechanism of endothelial dysfunction caused by H. parasuis has not been clarified. By using the transwell-based cell co-culture system, we demonstrate that knocking out resistin in porcine alveolar macrophages (PAMs) dramatically attenuated endothelial monolayer damage caused by H. parasuis. The resistin secreted by PAMs inhibited the expression of the tight junction proteins claudin-5 and occludin rather than the adherens junction protein VE-cadherin in co-cultured porcine aortic endothelial cells (PAECs). Furthermore, we demonstrate that resistin regulated claudin-5 and occludin expression and monolayer PAEC permeability in an LKB1/AMPK/mTOR pathway-dependent manner. Additionally, we reveal that the outer membrane lipoprotein gene lppA in H. parasuis induced resistin expression in PAMs, as deleting lppA reduced resistin expression in H. parasuis-infected PAMs, causing a significant change in LKB1/AMPK/mTOR pathway activity in co-cultured PAECs, thereby restoring tight junction protein levels and endothelial monolayer permeability. Thus, we postulate that the H. parasuis lppA gene enhances resistin production in PAMs, disrupting tight junctions in PAECs and causing endothelial barrier dysfunction. These findings elucidate the pathogenic mechanism of exudative inflammation caused by H. parasuis for the first time and provide a more profound angle of acute exudative inflammation caused by bacteria.

Positive association between serum resistin and smoking was strongest in homozygotes of the G-A haplotype at c.-420 C>G and c.-358 G>A in RETN promoter: the Toon Genome Study

Resistin is mainly expressed in human monocytes/macrophages and is associated with insulin resistance, inflammation, and atherosclerosis. Serum resistin is strongly correlated with the G-A haplotype defined by single nucleotide polymorphisms (SNPs) c.-420 C>G (SNP-420) (rs1862513) and c.-358 G>A (SNP-358) (rs3219175) in the promoter region of the human resistin gene (RETN). Smoking is also associated with insulin resistance. We investigated the association between smoking and serum resistin and the effect of the G-A haplotype on this association. Participants were recruited under the Toon Genome Study (an observational epidemiology research in the Japanese population). Of these, 1975 subjects genotyped for both SNP-420 and SNP-358 were analyzed for serum resistin by grouping them based on smoking status and G-A haplotype status. RETN mRNA, isolated from whole blood cells, was evaluated in smokers (n = 7) and age-, sex-, and BMI-matched non-smokers (n = 7) with the G-A haplotype homozygotes. Serum resistin tended to be higher in current smokers who smoked more cigarettes per day (P for trend < 0.0001). The positive association between serum resistin and smoking was strongest in the G-A haplotype homozygotes, followed by heterozygotes and non-carriers (interaction P < 0.0001). This positive association was stronger in the G-A homozygotes than the C-G homozygotes (interaction P < 0.0001). RETN mRNA was 1.40-fold higher in smokers than non-smokers with the G-A homozygotes (P = 0.022). Therefore, the positive association between serum resistin and smoking was strongest in the G-A haplotype homozygotes defined by RETN SNP-420 and SNP-358.

Changes in the Secretion of Melatonin and Selected Adipokines during the Progression of Parkinson's Disease-Preliminary Studies

Parkinson's disease (PD) is one of the most common neurodegenerative diseases affecting elderly people. Considering the gap in the literature on melatonin and adipokine levels in PD patients at various stages of the disease, we conducted a study to investigate the levels of selected parameters in PD patients at the disease's early (ES) and advanced (AS) stages. Melatonin, leptin, adiponectin, and resistin concentrations were measured in the blood serum of 20 PD patients without dyskinesia (ES), 24 PD patients with dyskinesia (AS), and 20 healthy volunteers as a control group (CG). The data were analyzed using ANOVA. Melatonin was significantly lower in ES (p < 0.05) and higher in AS patients (p < 0.05) compared to CG. The level of leptin was increased both in ES (p < 0.001) and AS (p < 0.001) versus CG, while resistin was increased only in patients with dyskinesia (p < 0.05). Higher melatonin (p < 0.001) and resistin (p < 0.05) and lower leptin (p < 0.05) levels were found in AS versus ES. The main findings of the study include the changes in inflammatory markers' levels during PD and a surprising increase in melatonin level in dyskinesia patients. Further research is necessary, which will be aimed at modulating the secretion of melatonin and adipokines as a treatment target for PD.

Adipokines: Deciphering the cardiovascular signature of adipose tissue

Obesity and hypertension are intimately linked due to the various ways that the important cell types such as vascular smooth muscle cells (VSMC), endothelial cells (EC), immune cells, and adipocytes, communicate with one another to contribute to these two pathologies. Adipose tissue is a very dynamic organ comprised primarily of adipocytes, which are well known for their role in energy storage. More recently adipose tissue has been recognized as the largest endocrine organ because of its ability to produce a vast number of signaling molecules called adipokines. These signaling molecules stimulate specific types of cells or tissues with many adipokines acting as indicators of adipocyte healthy function, such as adiponectin, omentin, and FGF21, which show anti-inflammatory or cardioprotective effects, acting as regulators of healthy physiological function. Others, like visfatin, chemerin, resistin, and leptin are often altered during pathophysiological circumstances like obesity and lipodystrophy, demonstrating negative cardiovascular outcomes when produced in excess. This review aims to explore the role of adipocytes and their derived products as well as the impacts of these adipokines on blood pressure regulation and cardiovascular homeostasis.

Associations of adipokines and metabolic hormones with low-density lipoprotein hypercholesterolemia in men and women under 45 years of age

Aim    To study the adipokine profile in young people with hypercholesterolemia and low-density lipoproteins (LDL) and to evaluate the relationship between concentrations of LDL cholesterol (LDL-C) and metabolic hormones in men and women younger than 45 years. Material and methods    This study included 304 subjects (group 1, 56 men with LDL-C concentration <2.1 mmol/l; group 2, 87 men with LDL-C concentration ≥4.2 mmol/l; group 3, 90 women with LDL-C concentration <2.1 mmol/l; and group 4, 71 women with LDL-C concentration ≥4.2 mmol/l). Serum concentrations of total cholesterol (C), triglycerides (TG), high-density lipoprotein C, and glucose were measured by an enzymatic assay with ThermoFisher Scientific kits and a KonelabPrime 30i biochemical analyzer. LDL-C was calculated using the Friedewald’s formula. Concentrations of amylin, C-peptide, ghrelin, glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1 (GLP-1), glucagon, interleukin 6, insulin, leptin, monocyte chemotactic protein 1 (MCP-1), pancreatic polypeptide (PP), peptide YY (PYY), tumor necrosis factor alpha (TNF-α), adiponectin, adipsin, lipocalin-2, plasminogen activator inhibitor 1 (PAI-1), and resistin were measured by multiplex analysis (Human Metabolic Hormone V3 and Human Adipokine Panel 1 panels).Results    The groups differed in traditional cardiometabolic risk factors. In the male and female patient groups with LDL-C ≥4.2 mmol/l, the prevalence of impaired fasting glucose, incidence of insulin resistance, TG, and TC were higher than in subjects with LDL-C <2.1 mmol/l. The odds for the presence of LDL hypercholesterolemia (LDL-C ≥4.2 mmol/l) were significantly associated with increased concentrations of C-peptide and lipocalin-2 in men and with increased concentrations of lipocalin-2 and decreased concentrations of GLP-1 in women (р<0.05).Conclusion    Increased concentrations of LDL-C in young people were associated with changes in the adipokine profile and with the presence of metabolic syndrome components. These results were confirmed by changes in blood concentrations of metabolic markers that characterize disorders of metabolic processes.

Adipose tissue aging: mechanisms and therapeutic implications

Adipose tissue, which is the crucial energy reservoir and endocrine organ for the maintenance of systemic glucose, lipid, and energy homeostasis, undergoes significant changes during aging. These changes cause physiological declines and age-related disease in the elderly population. Here, we review the age-related changes in adipose tissue at multiple levels and highlight the underlying mechanisms regulating the aging process. We also discuss the pathogenic pathways of age-related fat dysfunctions and their systemic negative consequences, such as dyslipidemia, chronic general inflammation, insulin resistance, and type 2 diabetes (T2D). Age-related changes in adipose tissue involve redistribution of deposits and composition, in parallel with the functional decline of adipocyte progenitors and accumulation of senescent cells. Multiple pathogenic pathways induce defective adipogenesis, inflammation, aberrant adipocytokine production, and insulin resistance, leading to adipose tissue dysfunction. Changes in gene expression and extracellular signaling molecules regulate the aging process of adipose tissue through various pathways. In addition, adipose tissue aging impacts other organs that are infiltrated by lipids, which leads to systemic inflammation, metabolic system disruption, and aging process acceleration. Moreover, studies have indicated that adipose aging is an early onset event in aging and a potential target to extend lifespan. Together, we suggest that adipose tissue plays a key role in the aging process and is a therapeutic target for the treatment of age-related disease, which deserves further study to advance relevant knowledge.

Serum Resistin Levels and Related Genetic Variants Are Associated With Bone Mineral Density in Postmenopausal Women

BACKGROUND

Osteoporosis is a multifactorial disorder and a number of genetic variants or loci responsible for bone mineral density (BMD) have been identified. Resistin, a novel adipokine has diverse role in human body including its function in bone remodeling. The objective of this study was to see the association of serum resistin levels and related genetic variants (rs3931020, rs13144478) with BMD in postmenopausal females.

METHODS

This comparative analytical study was conducted on postmenopausal osteoporotic (n=101), osteopenic (n=77) and non-osteoporotic (n=74) females. For comparison and correlational analysis, Kruskal-Wallis test and Spearman's rho correlation were used respectively. Hardy-Weinberg equilibrium (HWE) was calculated by using Chi-square test (χ²).

RESULTS

There was significant difference in the serum levels of resistin (p <0.001), among the three groups. Significant negative correlation of resistin was observed with BMD at various sites. Serum resistin levels were significantly low in the rs3931020 AA homozygous genotype (p = 0.010), and significantly high in the rs13144478 AT heterozygous genotype (p = 0.020), BMD at all sites except left femoral neck was significantly high in rs3931020 AA genotype, while BMD at lumbar spine, left hip and total BMD were significantly low in the rs13144478 TT homozygotes.

CONCLUSION

High serum resistin levels are associated with low BMD and single nucleotide variation in rs3931020 and rs13144478 may lead to high serum resistin levels and low bone mineral density. Resistin can serve as a new genetic marker, potential therapeutic target and predictor of osteoporosis.

Measurement of Plasma Resistin Concentrations in Horses with Metabolic and Inflammatory Disorders

Simple Summary

Obesity and its associated complications, such as metabolic syndrome, are an increasing problem in both humans and horses in the developed world. Adipose tissue is a key endocrine organ that communicates with other organs by multiple endocrine substances called adipokines. There is evidence to suggest that adipokines may contribute to the regulation of biological processes, such as metabolism, immunity, and inflammation. The aim of this study was to investigate the usefulness of one of these adipokines in horses, resistin, and its relationship with insulin dysregulation (ID) and inflammation. Seventy-two horses, included in one of the four following groups, were studied: healthy controls, horses with inflammatory conditions, horses with mild, and horses with severe ID. Plasma resistin concentrations were significantly different between groups, and the highest values were recorded in the inflammatory and severe ID groups. The lack of correlation of resistin with basal insulin concentration and the significant correlation of resistin with the inflammatory marker serum amyloid A suggest that, as is the case in humans, plasma resistin concentrations in horses are predominantly related to inflammatory conditions and not to ID.

Abstract

Obesity and its associated complications, such as metabolic syndrome, are an increasing problem in both humans and horses in the developed world. The expression patterns of resistin differ considerably between species. In rodents, resistin is expressed by adipocytes and is related to obesity and ID. In humans, resistin is predominantly produced by inflammatory cells, and resistin concentrations do not reflect the degree of obesity, although they may predict cardiovascular outcomes. The aim of this study was to investigate the usefulness of resistin and its relationship with ID and selected indicators of inflammation in horses. Seventy-two horses, included in one of the four following groups, were studied: healthy controls (C, n = 14), horses with inflammatory conditions (I, n = 21), horses with mild ID (ID1, n = 18), and horses with severe ID (ID2, n = 19). Plasma resistin concentrations were significantly different between groups and the higher values were recorded in the I and ID2 groups (C: 2.38 ± 1.69 ng/mL; I: 6.85 ± 8.38 ng/mL; ID1: 2.41 ± 2.70 ng/mL; ID2: 4.49 ± 3.08 ng/mL). Plasma resistin was not correlated with basal insulin concentrations. A significant (r = 0.336, p = 0.002) correlation was found between resistin and serum amyloid A. Our results show that, as is the case in humans, plasma resistin concentrations in horses are predominantly related to inflammatory conditions and not to ID. Horses with severe ID showed an elevation in resistin that may be secondary to the inflammatory status associated with metabolic syndrome.

High Serum Levels of Resistin is Associated With Acute Cerebral Infarction

BACKGROUND

The inflammatory process is involved in the pathogenesis of atherosclerosis and brain tissue injury following cerebral ischemia. Human resistin is a member of small cysteine-rich secreted proteins and has been implicated in inflammatory responses. This study investigated the association of serum resistin level with acute cerebral infarction (ACI). We also investigated its association with the short-term functional outcome.

METHODS

This study included 106 patients with ACI and 106 age-matched and sex-matched healthy control subjects. Serum resistin level was assessed by using enzyme-linked immunosorbent sandwich assay. The association of serum resistin levels with ACI was analyzed by logistic regression analysis.

RESULTS

The serum resistin level was significantly higher in patients with ACI than the control group [median (interquartile range), 35.7 ng/mL (13.0 to 70.5) ng/mL vs. 10.5 ng/ml (15.4 to 16.6), P<0.001]. Logistic regression analysis showed that serum resistin level was associated with an ACI (odds ratio=1.055, 95% confidence interval: 1.035-1.074, P<0.001). Among stroke subtypes, the serum resistin level was higher in the patients with large artery atherosclerosis than those with other subtypes (P=0.013). High resistin levels were also significantly associated with unfavorable functional outcome at discharge (odds ratio=1.043, 95% confidence interval: 1.024-1.063, P<0.001).

CONCLUSIONS

This study suggests the potential association of resistin with stroke and cerebral atherosclerosis. Increased serum resistin levels were also associated with early unfavorable neurological outcome.

Resistin levels and inflammatory and endothelial dysfunction markers in obese postmenopausal women with type 2 diabetes mellitus

BACKGROUND

Obesity-associated coronary heart disease (CHD) risk is higher in women than in men with type 2 diabetes (T2DM). Resistin, an adipokine secreted by adispose tissue, may contribute to this higher risk.

AIMS

To explore the relationships among resistin levels and common inflammatory and endothelial dysfunction markers and CHD risk in obese post-menopausal T2DM women.

METHODS

Serum levels of resistin, hsCRP, IL-6, Soluble vascular cell adhesion molecule (sVCAM), homocysteine (tHcy), HOMA-IR and metabolic parameters were determined in a group of 132 T2DM women with and without documented CHD and in 55 non-diabetic women.

RESULTS

Resistin, sVCAM, IL-6 and tHcy levels were comparable in T2DM and controls. CHD women showed higher resistin, sVCAM and tHcy levels than those without CHD, and for resistin this difference remained significant after age-adjustment (P = 0.013); conversely hsCRP were ~ 2X higher in T2DM women than in controls (P = 0.0132) without any difference according to CHD history. At univariate analysis resistin levels were significantly associated with age, waist circumference, hypertension, tHcy, hsPCR, sVCAM, IL-6, HDL-cholesterol, triglycerides and creatinine levels, but only creatinine, triglycerides, hsCRP, IL-6 and sVCAM were independently associated to resistin levels at stepwise regression analysis. Resistin levels were independently associated to CHD, increasing the risk by 1.15 times (0.986-1.344 95% CI), together with age, tHcy, LDL-C and hypertension.

CONCLUSIONS

Circulating resistin levels were comparable in obese/overweight T2DM and control women. In T2DM women, resistin levels correlated with markers of renal function, systemic inflammation and endothelial dysfunction and were independently associated with a higher CHD risk.

Apoptosis signal-regulating kinase 1 (ASK1) inhibition reduces endothelial cytokine production without improving permeability after toll-like receptor 4 (TLR4) challenge

Sepsis represents a life-threatening event often mediated by the host's response to pathogens such as gram-negative organisms, which release the proinflammatory lipopolysaccharide (LPS). Within the endothelium, the mitogen-activated protein kinase (MAPK) pathway is an important driver of endothelial injury during sepsis, of which oxidant-sensitive apoptosis signal-regulating kinase 1 (ASK1) is postulated to be a critical upstream regulator. We hypothesized that ASK1 would play a key role in endothelial inflammation during bacterial challenge. Utilizing RNA sequencing data from patients and cultured human microvascular endothelial cells (HMVECs), ASK1 expression was increased in sepsis and after LPS challenge. Two ASK1 inhibitors, GS444217 and MSC2023964A, reduced cytokine production in HMVECs following LPS stimulation, but had no effect on permeability as measured by transendothelial electrical resistance and intercellular space. MAPKs are known to interact with endothelial nitric oxide synthase (eNOS) and ASK1 expression levels correlated with eNOS expression in patients with septic shock. In addition, eNOS physically interacted with ASK1, though this interaction was not altered by ASK1 inhibition, nor did inhibition alter MAPK p38 activity. Instead, among MAPKs, ASK1 inhibition only impaired LPS-induced JNK phosphorylation. The reduction in JNK activation caused by ASK1 inhibition impaired JNK-mediated cytokine production without affecting permeability. Thus, LPS triggers JNK-dependent cytokine production that requires ASK1 activation, but both its effects on permeability and activation of p38 are ASK1-independent. These data demonstrate how distinct MAPK signaling pathways regulate endothelial inflammatory outputs during acute infectious challenge.

Serum resistin is predictive marker of development of new digital ulcers in systemic sclerosis

Systemic sclerosis (SSc) is autoimmune disease characterized by endothelial dysfunction and microvascular damage. Resistin has been implied in microvascular dysfunction. Objective of this study is to evaluate the association between baseline resistin and development of new digital ulcers (DUs) in SSc patients. At baseline, serum resistin has been assessed in 70 female SSc patients and 26 healthy controls (HC). In SSc patients, clinical assessment was performed at baseline and after a 52-weeks follow-up. Serum resistin level was increased in SSc patients compared to HC [5.89 ng/ml (2.5 ng/ml–8.1 ng/ml) vs 2.3 ng/ml (0.4 ng/ml–2.4 ng/ml), p = 0.0004)]. Resistin was lower (p = 0.005) in SSc patients with early capillaroscopic pattern than patients with active or late capillaroscopic pattern [2.49 ng/ml (0.89 ng/ml–5.81 ng/ml) vs 7.11 ng/ml (3.48 ng/ml–11.35 ng/ml) and 6.49 ng/ml (3.35 ng/ml–8.87 ng/ml), respectively]. After a 52-weeks follow-up, 34 (48.6%) patients developed new DUs. Median serum resistin was significantly higher in patients with new DUs than in patients without new DUs [6.54 ng/ml (3.35 ng/ml–11.02 ng/ml) vs 4.78 ng/ml (1.06 ng/ml–7.6 ng/ml), p = 0.019]. Kaplan–Meier curves show a significantly reduced free survival from DUs in patients with increased resistin (p = 0.002). In multivariate analysis, resistin is associated with the development of new DUs. Increased serum resistin level is a predictive marker of new DUs in SSc.

Is resistin the master link between inflammation and inflammation-related chronic diseases?

Resistin has been firstly discovered in mice and was identified as an adipose tissue-secreted hormone or adipokine linking obesity and insulin resistance. In humans, resistin has been characterized as a hormone expressed and secreted by Immune cells especially by macrophages, and was linked to many inflammatory responses including inflammation of adipose tissue due to macrophages' infiltration. Human and mouse resistin display sequence and structural similarities and also dissimilarities that could explain their different expression pattern. In mice, strong pieces of evidence clearly associated high resistin plasma levels to obesity and insulin resistance suggesting that resistin could play an important role in the onset and progression of obesity and insulin resistance via resistin-induced inflammation. In humans, the link between resistin and obesity/insulin resistance is still a matter of debate and needs more epidemiological studies. Also, resistin has been linked to other chronic diseases such as cardiovascular diseases and cancers where resistin has been proposed in many studies as a biological marker.

Regulation of vascular permeability in cancer metastasis

Enhancement of vascular permeability is indispensable for cancer metastasis. Weakened endothelial barrier function enhances vascular permeability. Circulating tumor cells moving in the microvasculature tend to invade into stromal tissue at the location where vascular permeability is enhanced. Many basic studies have identified permeability factors by using gene‐modified animals and cells. These factors directly/indirectly interact with endothelial cells. Here, we review vascular permeability factors and their molecular mechanisms. Interactions between tumor cells and endothelial cells are also discussed in the process of extravasation, one of the most critical steps in tumor metastasis. In some cases, primary tumors can manipulate permeability in a remote organ by secreting permeability factors. In addition, the importance of glycocalyx, which covers the endothelial cell surface, in controlling vascular permeability and tumor metastasis is also described. Furthermore, analysis of the hyperpermeable region found in a mouse model study is introduced. It clearly showed that tumor‐bearing mouse lungs had a hyperpermeable region due to the influence of a remote primary tumor, and fibrinogen deposition was observed in that region. Given that fibrinogen was reported to be a permeability factor and a key regulator of inflammation, eliminating fibrinogen deposition may prevent future metastasis.

The adipokine Retnla deficiency increases responsiveness to cardiac repair through adiponectin-rich bone marrow cells

Resistin-like alpha (Retnla) is a member of the resistin family and known to modulate fibrosis and inflammation. Here, we investigated the role of Retnla in the cardiac injury model. Myocardial infarction (MI) was induced in wild type (WT), Retnla knockout (KO), and Retnla transgenic (TG) mice. Cardiac function was assessed by echocardiography and was significantly preserved in the KO mice, while worsened in the TG group. Angiogenesis was substantially increased in the KO mice, and cardiomyocyte apoptosis was markedly suppressed in the KO mice. By Retnla treatment, the expression of p21 and the ratio of Bax to Bcl2 were increased in cardiomyocytes, while decreased in cardiac fibroblasts. Interestingly, the numbers of cardiac macrophages and unsorted bone marrow cells (UBCs) were higher in the KO mice than in the WT mice. Besides, phosphorylated histone H3(+) cells were more frequent in bone marrow of KO mice. Moreover, adiponectin in UBCs was notably higher in the KO mice compared with WT mice. In an adoptive transfer study, UBCs were isolated from KO mice to transplant to the WT infarcted heart. Cardiac function was better in the KO-UBCs transplanted group in the WT-UBCs transplanted group. Taken together, proliferative and adiponectin-rich bone marrow niche was associated with substantial cardiac recovery by suppression of cardiac apoptosis and proliferation of cardiac fibroblast.

Adipokines and Chronic Rheumatic Diseases: from Inflammation to Bone Involvement

Besides its well-known role as energy storage tissue, adipose tissue is a biologically active tissue that can also be considered as an endocrine organ, as it is able to secrete adipokines. These bioactive factors, similar in structure to cytokines, are involved in several physiological and pathological conditions, such as glucose homeostasis, angiogenesis, blood pressure regulation, control of food intake, and also inflammation and bone homeostasis via endocrine, paracrine, and autocrine mechanisms. Given their pleiotropic functions, the role of adipokines has been evaluated in chronic rheumatic osteoarticular inflammatory diseases, particularly focusing on their effects on inflammatory and immune response and on bone alterations. Indeed, these diseases are characterized by different bone complications, such as local and systemic bone loss and new bone formation. The aim of this review is to summarize the role of adipokines in rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, osteoarthritis, and osteoporosis, especially considering their role in the pathogenesis of bone complications typical of these conditions.

Metformin as adjunctive therapy for dengue in overweight and obese patients: a protocol for an open-label clinical trial (MeDO)

Background:  Dengue is a disease of major global importance. While most symptomatic infections are mild, a small proportion of patients progress to severe disease with risk of hypovolaemic shock, organ dysfunction and death.  In the absence of effective antiviral or disease modifying drugs, clinical management is solely reliant on supportive measures. Obesity is a growing problem among young people in Vietnam and is increasingly recognised as an important risk factor for severe dengue, likely due to alterations in host immune and inflammatory pathways. Metformin, a widely used anti-hyperglycaemic agent with excellent safety profile, has demonstrated potential as a dengue therapeutic in vitro and in a retrospective observational study of adult dengue patients with type 2 diabetes.  This study aims to assess the safety and tolerability of metformin treatment in overweight and obese dengue patients, and investigate its effects on several clinical, immunological and virological markers of disease severity. Methods: This open label trial of 120 obese/overweight dengue patients will be performed in two phases, with a metformin dose escalation if no safety concerns arise in phase one. The primary endpoint is identification of clinical and laboratory adverse events.  Sixty overweight and obese dengue patients aged 10-30 years will be enrolled at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam. Participants will complete a 5-day course of metformin therapy and be compared to a non-treated group of 60 age-matched overweight and obese dengue patients. Discussion:  Previously observed antiviral and immunomodulatory effects of metformin make it a promising dengue therapeutic candidate in appropriately selected patients. This study will assess the safety and tolerability of adjunctive metformin in the management of overweight and obese young dengue patients, as well as its effects on markers of viral replication, endothelial dysfunction and host immune responses.  Trial registration: ClinicalTrials.gov: NCT04377451 (May 6 th 2020).

Metformin as adjunctive therapy for dengue in overweight and obese patients: a protocol for an open-label clinical trial (MeDO)

Background:  Dengue is a disease of major global importance. While most symptomatic infections are mild, a small proportion of patients progress to severe disease with risk of hypovolaemic shock, organ dysfunction and death.  In the absence of effective antiviral or disease modifying drugs, clinical management is solely reliant on supportive measures. Obesity is a growing problem among young people in Vietnam and is increasingly recognised as an important risk factor for severe dengue, likely due to alterations in host immune and inflammatory pathways. Metformin, a widely used anti-hyperglycaemic agent with excellent safety profile, has demonstrated potential as a dengue therapeutic in vitro and in a retrospective observational study of adult dengue patients with type 2 diabetes.  This study aims to assess the safety and tolerability of metformin treatment in overweight and obese dengue patients, and investigate its effects on several clinical, immunological and virological markers of disease severity.

Methods: This open label trial of 120 obese/overweight dengue patients will be performed in two phases, with a metformin dose escalation if no safety concerns arise in phase one. The primary endpoint is identification of clinical and laboratory adverse events.  Sixty overweight and obese dengue patients aged 10-30 years will be enrolled at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam. Participants will complete a 5-day course of metformin therapy and be compared to a non-treated group of 60 age-matched overweight and obese dengue patients.

Discussion:  Previously observed antiviral and immunomodulatory effects of metformin make it a promising dengue therapeutic candidate in appropriately selected patients. This study will assess the safety and tolerability of adjunctive metformin in the management of overweight and obese young dengue patients, as well as its effects on markers of viral replication, endothelial dysfunction and host immune responses. 

Trial registration: ClinicalTrials.gov: NCT04377451 (May 6 ^th 2020).

Adipokines: New Potential Therapeutic Target for Obesity and Metabolic, Rheumatic, and Cardiovascular Diseases

Besides its role as an energy storage organ, adipose tissue can be viewed as a dynamic and complex endocrine organ, which produces and secretes several adipokines, including hormones, cytokines, extracellular matrix (ECM) proteins, and growth and vasoactive factors. A wide body of evidence showed that adipokines play a critical role in various biological and physiological functions, among which feeding modulation, inflammatory and immune function, glucose and lipid metabolism, and blood pressure control. The aim of this review is to summarize the effects of several adipokines, including leptin, diponectin, resistin, chemerin, lipocalin-2 (LCN2), vaspin, omentin, follistatin-like 1 (FSTL1), secreted protein acidic and rich in cysteine (SPARC), secreted frizzled-related protein 5 (SFRP5), C1q/TNF-related proteins (CTRPs), family with sequence similarity to 19 member A5 (FAM19A5), wingless-type inducible signaling pathway protein-1 (WISP1), progranulin (PGRN), nesfatin-1 (nesfatin), visfatin/PBEF/NAMPT, apelin, retinol binding protein 4 (RPB4), and plasminogen activator inhibitor-1 (PAI-1) in the regulation of insulin resistance and vascular function, as well as many aspects of inflammation and immunity and their potential role in managing obesity-associated diseases, including metabolic, osteoarticular, and cardiovascular diseases.

Role of adipokines in systemic sclerosis pathogenesis

Systemic sclerosis (SSc) is a chronic autoimmune connective tissue disease with manifestations in multiple organs, including the skin, lung, heart, joints, gastrointestinal tract, kidney, and liver. Its pathophysiology is characterized by inflammation, fibrosis, and vascular damage, with an increased expression of numerous cytokines, chemokines, and growth factors. However, besides these growth factors and cytokines, another group of molecules may be involved in the pathogenesis of SSc: the adipokines. Adipokines are proteins with metabolic and cytokine-like properties, which were originally found to be expressed by adipose tissue. However, their expression is not limited to this tissue, and they can also be found in other organs. Therefore, this review will describe the current knowledge regarding adipokines in the context of SSc and try to elucidate their potential role in the pathogenesis of SSc.

The role of adipokines in the modulation of lymphoid lineage cell development and activity: An overview

Adipokines are predominantly known to play a vital role in the control of food intake, energy homeostasis and regulation of glucose and lipid metabolism. However, evidence supporting the concept of their extensive involvement in immune system defence mechanisms and inflammatory processes continues to grow. Some of the adipokines, that is, leptin and resistin, have been recognized to exhibit mainly pro-inflammatory properties, whereas others such as visfatin, chemerin, apelin and vaspin have been found to exert regulatory effects. In contrast, adiponectin or omentin are known for their anti-inflammatory activities. Hence, adipokines influence the activity of various cells engaged in innate immune response and inflammatory processes mainly by affecting adhesion molecule expression, chemotaxis, apoptosis and phagocytosis, as well as mediators production and release. However, much less is known about the role of adipokines in processes involving lymphoid lineage cells. This review summarizes the current knowledge regarding the importance of different adipokines in the lymphopoiesis, recirculation, differentiation and polarization of lymphoid lineage cells. It also provides insight into the influence of selected adipokines on the activity of those cells in tissues.

Adipocytokines: Are they the Theory of Everything?

INTRODUCTION

Adipose tissue secretes various bioactive peptides/proteins, immune molecules and inflammatory mediators which are known as adipokines or adipocytokines. Adipokines play important roles in the maintenance of energy homeostasis, appetite, glucose and lipid metabolism, insulin sensitivity, angiogenesis, immunity and inflammation. Enormous number of studies from all over the world proved that adipocytokines are involved in the pathogenesis of diseases affecting nearly all body systems, which raises the question whether we can always blame adipocytokines as the triggering factor of every disease that may hit the body.

OBJECTIVE

Our review targeted the role played by adipocytokines in the pathogenesis of different diseases affecting different body systems including diabetes mellitus, kidney diseases, gynecological diseases, rheumatologic disorders, cancers, Alzheimer's, depression, muscle disorders, liver diseases, cardiovascular and lung diseases.

METHODOLOGY

We cited more than 33 recent literature reviews that discussed the role played by adipocytokines in the pathogenesis of different diseases affecting different body systems.

CONCLUSION

More evidence is being discovered to date about the role played by adipocytokines in more diseases and extra research is needed to explore hidden roles played by adipokine imbalance on disease pathogenesis.

The dynamic process of dietary soybean β-conglycinin in digestion, absorption, and metabolism among different intestinal segments in grass carp (Ctenopharyngodon idella)

The present study aimed to investigate the dynamic process of soybean β-conglycinin in digestion, absorption, and metabolism in the intestine of grass carp (Ctenopharyngodon idella). Fish fed with 80 g β-conglycinin/kg diet for 7 weeks, the intestinal digestive enzyme was extracted to hydrolyze β-conglycinin in vitro, the free amino acid and its metabolism product contents in intestinal segments were analyzed. The present study first found that β-conglycinin cannot be thoroughly digested by fish intestine digestive enzyme and produces new products (about 60- and 55-kDa polypeptides). The indigestible β-conglycinin further caused the free amino acid imbalance, especially caused free essential amino acid deficiency in the proximal intestine but excess in the distal intestine. Moreover, these results might be partly associated with the effect of β-conglycinin in amino acid transporters and tight junction-regulated paracellular pathway. Finally, dietary β-conglycinin increased the content of amino acid catabolism by-product ammonia while decreased the amino acid anabolism product carnosine content in the proximal intestine and distal intestine. Thus, the current study first and systemically explored the dynamic process of β-conglycinin in digestion, absorption, and metabolism, which further supported our previous study that dietary β-conglycinin suppressed fish growth and caused intestine injure.

Resistin Is Increased in Periodontal Cells and Tissues: In Vitro and In Vivo Studies

Resistin, a proinflammatory adipokine, is elevated in many inflammatory diseases. However, little is known about its performance in periodontitis. The present study is aimed at evaluating resistin expression and synthesis in periodontal cells and tissues under inflammatory/microbial stress in addition to its effects on the periodontium. In vivo, 24 male rats were randomly divided into two groups: control and ligature-induced periodontal disease. After 6 and 12 days, animals were sacrificed to analyze gene expression of adipokines, bone loss, inflammation, and resistin synthesis. In vitro, human periodontal ligament (PDL) fibroblasts were used to evaluate the expression of resistin after inflammatory stimuli. In addition, PDL fibroblasts were exposed to resistin to evaluate its role on soft and hard tissue metabolism markers. The periodontitis group demonstrated significant bone loss, an increase in the number of inflammatory cells and vascular structures, an increase in resistin expression and synthesis, and a decrease in the expression of adiponectin, leptin, and its functional receptor. PDL fibroblasts showed a significant increase in resistin expression and synthesis in response to the inflammatory stimulus by IL-1β. Resistin induced an increase in cytokine expression and a decrease in the regulation of some hard tissue and matrix formation genes in PDL fibroblasts. These data indicate that resistin is produced by periodontal cells and tissues, and this effect is enhanced by inflammatory stimuli. Moreover, resistin seems to interfere with soft and hard tissue metabolism during periodontitis by reducing markers related to matrix formation and bone tissue.

Adipokines and Adipose Tissue-Related Metabolites, Nuts and Cardiovascular Disease

Adipose tissue is a complex structure responsible for fat storage and releasing polypeptides (adipokines) and metabolites, with systemic actions including body weight balance, appetite regulation, glucose homeostasis, and blood pressure control. Signals sent from different tissues are generated and integrated in adipose tissue; thus, there is a close connection between this endocrine organ and different organs and systems such as the gut and the cardiovascular system. It is known that functional foods, especially different nuts, may be related to a net of molecular mechanisms contributing to cardiometabolic health. Despite being energy-dense foods, nut consumption has been associated with no weight gain, weight loss, and lower risk of becoming overweight or obese. Several studies have reported beneficial effects after nut consumption on glucose control, appetite suppression, metabolites related to adipose tissue and gut microbiota, and on adipokines due to their fatty acid profile, vegetable proteins, l-arginine, dietary fibers, vitamins, minerals, and phytosterols. The aim of this review is to briefly describe possible mechanisms implicated in weight homeostasis related to different nuts, as well as studies that have evaluated the effects of nut consumption on adipokines and metabolites related to adipose tissue and gut microbiota in animal models, healthy individuals, and primary and secondary cardiovascular prevention.

Endothelial tight junctions and their regulatory signaling pathways in vascular homeostasis and disease

Endothelial tight junctions (TJs) regulate the transport of water, ions, and molecules through the paracellular pathway, serving as an important barrier in blood vessels and maintaining vascular homeostasis. In endothelial cells (ECs), TJs are highly dynamic structures that respond to multiple external stimuli and pathological conditions. Alterations in the expression, distribution, and structure of endothelial TJs may lead to many related vascular diseases and pathologies. In this review, we provide an overview of the assessment methods used to evaluate endothelial TJ barrier function both in vitro and in vivo and describe the composition of endothelial TJs in diverse vascular systems and ECs. More importantly, the direct phosphorylation and dephosphorylation of TJ proteins by intracellular kinases and phosphatases, as well as the signaling pathways involved in the regulation of TJs, including and the protein kinase C (PKC), PKA, PKG, Ras homolog gene family member A (RhoA), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt, and Wnt/β-catenin pathways, are discussed. With great advances in this area, targeting endothelial TJs may provide novel treatment for TJ-related vascular pathologies.

RANK/RANKL/OPG pathway is an important for the epigenetic regulation of obesity

Obesity is a complex disorder that is influenced by genetic and environmental factors. DNA methylation is an epigenetic mechanism that is involved in development of obesity and its metabolic complications. The aim of this study was to investigate the association between the RANKL and c-Fos gene methylation on obesity with body mass index (BMI), lipid parameters, homeostasis model assessment of insulin resistance (HOMA-IR), plasma leptin, adiponectin and resistin levels. The study included 68 obese and 46 non-obese subjects. Anthropometric parameters, including body weight, body mass index, waist circumference, and waist-hip ratio, were assessed. Serum glucose, triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), plasma leptin, adiponectin and resistin levels were measured. Methylation status of RANKL and c-Fos gen were evaluated by MS-HRM. Statistically significant differences were observed between obese patients and the controls with respect to RANKL and c-Fos gene methylation status (p < 0.001). Also, statistically significant importance was observed RANKL gene methylation and increased level of leptin in obese subjects (p = 0.0081). At the same time, statistically significant association between methylation of c-Fos and increased level of adiponectin was observed in obese patients (p = 0.03) On the other hand, decreased level of resistin was observed where the c-Fos was unmetyladed in controls (p = 0.01). We conclude that methylation of RANKL and c-Fos genes have significant influences on obesity and adipokine levels. Based on literature this was the first study which shows the interactions between RANKL and c-Fos methylation and obesity.

Endothelial permeability, LDL deposition, and cardiovascular risk factors-a review

Early atherosclerosis features functional and structural changes in the endothelial barrier function that affect the traffic of molecules and solutes between the vessel lumen and the vascular wall. Such changes are mechanistically related to the development of atherosclerosis. Proatherogenic stimuli and cardiovascular risk factors, such as dyslipidaemias, diabetes, obesity, and smoking, all increase endothelial permeability sharing a common signalling denominator: an imbalance in the production/disposal of reactive oxygen species (ROS), broadly termed oxidative stress. Mostly as a consequence of the activation of enzymatic systems leading to ROS overproduction, proatherogenic factors lead to a pro-inflammatory status that translates in changes in gene expression and functional rearrangements, including changes in the transendothelial transport of molecules, leading to the deposition of low-density lipoproteins (LDL) and the subsequent infiltration of circulating leucocytes in the intima. In this review, we focus on such early changes in atherogenesis and on the concept that proatherogenic stimuli and risk factors for cardiovascular disease, by altering the endothelial barrier properties, co-ordinately trigger the accumulation of LDL in the intima and ultimately plaque formation.

Resistin induces breast cancer cells epithelial to mesenchymal transition (EMT) and stemness through both adenylyl cyclase-associated protein 1 (CAP1)-dependent and CAP1-independent mechanisms

Breast cancer incidence and metastasis in postmenopausal women are known to associate with obesity, but the molecular mechanisms behind this association are largely unknown. We investigated the effect of adipokine resistin on epithelial to mesenchymal transition (EMT) and stemness in breast cancer cells in vitro. Previous reports demonstrated that the inflammatory actions of resistin are mediated by the adenylyl cyclase-associated protein 1 (CAP1), which serves as its receptor. As a model for our study, we used MCF-7 and MDA-MB-231 breast cancer and MCF-10A breast epithelial cells. We showed that in MCF-7 cells resistin increases the migration of MCF-7 and MDA-MB-231 cells and induces the formation of cellular protrusions through reorganization of F-actin filaments. Resistin upregulated the expression of mesenchymal markers involved in EMT (SNAIL, SLUG, ZEB1, TWIST1, fibronectin, and vimentin), and downregulated those of epithelial markers (E-cadherin and claudin-1). Resistin also potentiated the nuclear translocation of SNAIL protein, indicating initiation of EMT reprogramming. We further induced EMT in non-carcinogenic breast epithelial MCF-10A cells demonstrating that the effects of resistin on EMT were not breast cancer cell specific. In order to assess whether resistin-induced EMT depends on CAP1, we used siRNA approach to silence CAP1 gene in MCF-7 cells. Results demonstrated that when CAP1 was silenced, the induction of SNAIL, ZEB1 and vimentin expression by resistin as well as SNAIL and ZEB1 nuclear translocation, were abolished. Additionally, CAP1 silencing resulted in a suppression of MCF-7 cells migration. We performed quantitative PCR array profiling the expression of 84 genes related to cancer stem cells (CSC), pluripotency and metastasis and selected a set of genes (ALDH1A1, ITGA4, LIN28B, SMO, KLF17, PTPRC, PROM1, SIRT1, and PECAM1) that were modulated by resistin. Further experiments demonstrated that the effect of resistin on the expression of some of these genes (PROM1, PTPRC, KLF17, SIRT1, and PECAM1) was also dependent on CAP1. Our results demonstrate that resistin promotes the metastatic potential of breast cancer cells by inducing EMT and stemness and some of these effects are mediated by CAP1.

Adipokine expression in systemic sclerosis lung and gastrointestinal organ involvement

OBJECTIVES

The immunomodulatory properties of adipokines have previously been reported in autoimmune disorders. Less is known about the role of adipokines in systemic sclerosis (SSc). Lung and gastrointestinal tract are frequently involved in SSc; therefore, these organs were analyzed for adipokine expression as well as pulmonary samples of patients suffering from idiopathic pulmonary fibrosis (IPF) as comparison.

METHODS

Gastric samples (antrum, corpus) of SSc were analyzed immunohistochemically for adiponectin, resistin and visfatin compared with non-SSc related gastritis. Inflammatory cells were quantified in gastric samples and correlated with adipokine expression. Lung samples of SSc, IPF and healthy controls were also analyzed. Protein levels of lung tissue lysates and bronchoalveolar lavages (BAL) in minor fibrotic stages were measured by ELISA.

RESULTS

Lung sections of donor parenchyma showed significantly stronger adiponectin signals as IPF and SSc (donor vs. IPF: p < 0.0001). In SSc and IPF, resistin and visfatin were increased within immune cell infiltrates, but overall no difference in expression for resistin or visfatin compared to controls was observed. In BAL and lung protein lysates of early stages of fibrosis, adiponectin and visfatin were not reduced in IPF and SSc compared to controls. In gastric samples collected by standard endoscopic gastric biopsy, adiponectin was also significantly reduced in SSc- compared to non-SSc gastritis (p = 0.049) while resistin and visfatin were comparable although deeper fibrotic layers were not included in the respective samples. Adiponectin-positive tissues showed higher amounts of CD4⁺ but not CD8⁺ T cells. Controls showed no correlation between CD4⁺ T cells and resistin, whereas SSc showed significantly more CD4⁺ T cells in resistin-negative tissues.

CONCLUSION

Adipokines are expressed in gastric and lung samples of patients with SSc and in lung samples affected by IPF. Prominently, adiponectin levels were reduced in fibrotic SSc gastritic tissue as well as in IPF and SSc lung tissue. Consequently, adiponectin expression seems to be associated with fibrotic progression in the context of SSc and IPF.

Resistin impairs activation of protein C by suppressing EPCR and increasing SP1 expression

Endothelial cells are vital to blood coagulation and maintain whole body hemostasis. Binding of endothelial cells to endothelial protein C receptor (EPCR) and thrombomodulin (TM) is essential to the formation of activated protein C (APC), one of the key factors regulating blood coagulation. In our study, we showed that resistin, an adipocyte hormone, suppresses thrombin-induced protein C activation in endothelial cells. Resistin treatment results in a reduction in EPCR expression, but not TM. Mechanistically, we demonstrate that resistin induces expression of the nuclear transcription factor SP-1, which could lead to downregulation of EPCR. Both inhibition and silencing of SP1 protein abolishes abnormal APC generation induced by resistin. Collectively, our data support a new role of resistin in disturbing APC formation.

Adipocytokine Involvement in Innate Immune Mechanisms

The innate immune response is defined as an immensely complex and sophisticated process aimed at defending the organism against any disturbance in the body homeostasis, including invading pathogens. It requires a close cooperation of a vast amount of different cell types, recognized as inflammatory migrating cells, as well as stationary cells that form tissues. Moreover, innate immune mechanisms require an efficient functioning of various humoral components that exert a significant impact on physiological and pathological processes. Apart from commonly mentioned humoral factors, this group also includes a family of proteins known as adipocytokines that may act as pro- or anti-inflammatory agents or act both ways. Leptin, predominantly characterized as a proinflammatory adipokine, plays a crucial role in endothelium remodeling and regulation, as well as in cell survival and production of numerous cytokines. Adiponectin, similar to leptin, acts on the endothelial cells and the phagocytic properties of immune cells; however, it exerts an anti-inflammatory impact. Resistin has a documented role in the control of angiogenesis and stimulation of proinflammatory mediator generation and release. Furthermore, there are adipokines, ie, visfatin and chemerin, whose participation in the inflammatory processes is ambiguous. This review focuses on the current knowledge on the extensive role of selected adipokines in innate immune response.

Vasodilator-Stimulated Phosphoprotein: Regulators of Adipokines Resistin and Phenotype Conversion of Epicardial Adipocytes

Background

Endothelial dysfunction plays a central part in the pathogenesis of coronary atherosclerosis. The adipokine resistin is one of the key players in endothelial cell dysfunction. In addition, the role of epicardial fat in coronary artery endothelial dysfunction is also emphasized.

We investigated whether vasodilator-stimulated phosphoprotein (VASP) is involved in resistin-related endothelial dysfunction and the phenotype conversion of epicardial adipocytes.

Material/Methods

Cell proliferation and migration were evaluated by MTT and Transwell chamber assay, respectively. Next, we took epicardial fat samples from patients with valvular heart disease and non-coronary artery disease. Gene expression was determined by reverse transcription-quantitative polymerase chain reaction and relative abundance of the protein by Western blotting.

Results

Resistin induced endothelial proliferation and migration in a dose-dependent manner. Both resistin-induced cell proliferation and migration were effectively blocked by ablation of VASP. The brown adipose tissue-specific genes for uncoupling protein 1 (UCP-1) and PR-domain-missing16 (PRDM16) decreased, but the white adipose tissue-specific genes for resistin and RIP140 increased in VASP-deficient adipocytes compared with the LV-sicntr group. However, disruption of the Ras homolog gene family member A (RhoA) /Rho-associated kinase (ROCK) in VASP-deficient adipocytes with specific inhibitors inverted the adipocyte phenotype existing in VASP-deficient adipocytes. Furthermore, the expressions of proinflammatory cytokines interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemoattractantprotein-1 (MCP-1) in VASP-deficient adipocytes were markedly upregulated compared with the LV-sicntr group.

Conclusions

These results suggest a physiological role for VASP in coronary atherosclerosis through regulating adipokine resistin and phenotype conversion of epicardial adipose tissue.

Serum resistin is causally related to mortality risk in patients with type 2 diabetes: preliminary evidences from genetic data

Resistin has been firmly associated with all-cause mortality. We investigated, whether, in patients with type 2 diabetes (T2D), this association is sustained by a cause-effect relationship. A genotype risk score (GRS), created by summing the number of resistin increasing alleles of two genome-wide association studies (GWAS)-derived single nucleotide polymorphisms (SNPs), serum resistin measurements and all-cause death records were obtained in 1,479 (403 events/12,454 person-years), patients with T2D from three cohorts, Gargano Heart Study-prospective design (n = 350), Gargano Mortality Study (n = 698) and Foggia Mortality Study (n = 431), from Italy. GRS was strongly associated with serum resistin in a non-linear fashion (overall p = 3.5 * 10^-7) with effect size modest for GRS = 1 and 2 and much higher for GRS >3, with respect to GRS = 0. A significant non-linear association was observed also between GRS and all-cause mortality (overall p = 3.3 * 10^-2), with a low effect size for GRS = 1 and 2, and nearly doubled for GRS ≥ 3, with respect to GRS = 0. Based on the above-reported associations, each genetic equivalent SD increase in log-resistin levels showed a causal hazard ratio of all-cause mortality equal to 2.17 (95%CI: 1.22-3.87), thus providing evidence for a causal role of resistin in shaping the risk of mortality in diabetic patients.

Linking resistin, inflammation, and cardiometabolic diseases

Adipose tissue secretes a variety of bioactive substances that are associated with chronic inflammation, insulin resistance, and an increased risk of type 2 diabetes mellitus. While resistin was first known as an adipocyte-secreted hormone (adipokine) linked to obesity and insulin resistance in rodents, it is predominantly expressed and secreted by macrophages in humans. Epidemiological and genetic studies indicate that increased resistin levels are associated with the development of insulin resistance, diabetes, and cardiovascular disease. Resistin also appears to mediate the pathogenesis of atherosclerosis by promoting endothelial dysfunction, vascular smooth muscle cell proliferation, arterial inflammation, and the formation of foam cells. Thus, resistin is predictive of atherosclerosis and poor clinical outcomes in patients with cardiovascular disease and heart failure. Furthermore, recent evidence suggests that resistin is associated with atherogenic dyslipidemia and hypertension. The present review will focus on the role of human resistin in the pathogeneses of inflammation and obesity-related diseases.

Adiponectin/resistin interplay in serum and in adipose tissue of obese and normal-weight individuals

BACKGROUND

The interplay between adiponectin and resistin, the two adipokines of opposite effects, may determine the metabolic profile of obese individuals and development of obesity-related complications. The current study was conducted to assess how adiponectin/resistin interplay in sera and adipose tissues may influence the metabolic profile of obese and normal-weight subjects.

METHODS

Concentrations of adiponectin and resistin were measured on protein level by immunoassay in visceral and subcutaneous adipose tissues from 50 obese (body mass index > 40 kg/m²) and 28 normal-weight (body mass index 20-24.9 kg/m²) individuals. Simultaneously expression of ADIPOQ and RETN (encoding adiponectin and resistin, respectively) was assessed on mRNA level by real-time PCR.

RESULTS

ADIPOQ mRNA (P = 0.0001) and adiponectin protein (P = 0.0013) levels were lower, while RETN mRNA (P = 0.0338) and resistin (P < 0.0001)-higher in subcutaneous adipose tissues of obese subjects. ADIPOQ and RETN mRNA levels did not correlate with protein concentrations in the investigated adipose tissues. In obesity adiponectin serum concentrations correlated positively with ADIPOQ mRNA in subcutaneous adipose tissue (P = 0.005) and negatively with protein levels in visceral adipose tissue (P = 0.001). Obesity was associated with higher adiponectin-resistin index value in sera (P < 0.0001) and decreased in subcutaneous adipose tissue (P < 0.001), but only adiponectin-resistin index measured in sera was significantly higher in obese with the metabolic syndrome (P = 0.04).

CONCLUSIONS

Obesity affects synthesis of adiponectin and resistin mainly in subcutaneous adipose tissue. The adiponectin-resistin index assessed in the adipose tissues has a different prognostic value compared to the adiponectin-resistin index in serum and does not reflect a metabolic risk in obese individuals.

PKCε mediates resistin-induced NADPH oxidase activation and inflammation leading to smooth muscle cell dysfunction and intimal hyperplasia

BACKGROUND AND AIMS

Resistin has been implicated in cardiovascular disease and poor interventional cardiovascular outcomes. Previous studies by our group demonstrated resistin promoted vascular smooth muscle cell (VSMC) migration through protein kinase C epsilon (PKCε) pathways, while few others showed that resistin induced reactive oxygen species (ROS) generation in various cell types. In this study, we aim to systemically examine the functional role of resistin at the cellular and tissue levels as well as the potential mechanistic relationship between resistin-induced PKCε activation and ROS production.

METHODS

Plasma collected from patients undergoing carotid interventions was analyzed for resistin level and ROS. VSMCs were treated with resistin in the presence or absence of PKCε and NADPH oxidase (Nox)-specific inhibitors. Intracellular ROS production was analyzed using confocal microscopy and Nox activity with chemiluminescence. In vivo studies were performed in apolipoprotein E knock out (ApoE^-/-) mice to determine therapeutic effects of PKCε-specific inhibitor, using the guide-wire injury model.

RESULTS

We observed significant correlation between plasma resistin and circulating levels of oxidative stress in patients with severe atherosclerotic disease. We also demonstrated that resistin induced ROS production via PKCε-mediated Nox activation. Resistin-induced ROS production was time-dependent, and Nox4 was the primary isoform involved. Inhibition of Nox completely abolished resistin-exaggerated VSMC proliferation, migration and dedifferentiation, as well as pro-inflammatory cytokine release. Upstream modulation of PKCε significantly reduced resistin-mediated cytosolic ROS, Nox activity and VSMC dysfunction. Moreover, PKCε-specific inhibitor mitigated resistin-induced Nox activation and intimal hyperplasia in ApoE^-/- mice.

CONCLUSIONS

Resistin-associated VSMC dysfunction and intimal hyperplasia are related to PKCε-dependent Nox activation and ROS generation. Targeting the PKCε-Nox pathway may represent a novel strategy in managing resistin-associated atherosclerotic complications.

The effect of omega- 3 polyunsaturated fatty acids on endothelial tight junction occludin expression in rat aorta during lipopolysaccharide-induced inflammation

OBJECTIVES

Occludin is essential for proper assembly of tight junctions (TJs) which regulate paracellular endothelial permeability. Omega-3 polyunsaturated fatty acids (Ω-3 PUFA) protect endothelial barrier function against injury.

MATERIALS AND METHODS

We examined anti-inflammatory effect of Ω-3 PUFA intake (30 mg/kg/day for 10 days) on expression and location of occludin in the aorta of adult Wistar rats after a single dose of bacterial lipopolysaccharide (LPS, Escherichia coli, 1 mg/kg). The ultrastructure of TJs after LPS administration was also investigated. We measured plasma levels of C-reactive protein (CRP), Malondialdehyde (MDA) and CD68 expression and determined the total activity of NO synthase (NOS) in the aortic tissue.

RESULTS

LPS induced a significant decrease of occludin expression accompanied by structural alterations of TJs. Levels of CRP, MDA, CD68 and NOS activity were elevated after LPS injection compared to controls indicating presence of moderate inflammation. Ω-3 PUFA supplementation did not affect occludin expression in treated inflammatory group. However they reduced CRP and MDA concentration and CD68 expression, but conversely, they increased NOS activity compared to inflammatory group.

CONCLUSION

Our results indicate that a single dose of LPS could have a long-term impact on occludin expression and thus contribute to endothelial barrier dysfunction. 10-day administration of Ω-3 PUFA had partial anti-inflammatory effects on health of rats without any effect on occludin expression.

Insights into the molecular mechanisms of diabetes-induced endothelial dysfunction: focus on oxidative stress and endothelial progenitor cells

Diabetes mellitus is a heterogeneous, multifactorial, chronic disease characterized by hyperglycemia owing to insulin insufficiency and insulin resistance (IR). Recent epidemiological studies showed that the diabetes epidemic affects 382 million people worldwide in 2013, and this figure is expected to be 600 million people by 2035. Diabetes is associated with microvascular and macrovascular complications resulting in accelerated endothelial dysfunction (ED), atherosclerosis, and cardiovascular disease (CVD). Unfortunately, the complex pathophysiology of diabetic cardiovascular damage is not fully understood. Therefore, there is a clear need to better understand the molecular pathophysiology of ED in diabetes, and consequently, better treatment options and novel efficacious therapies could be identified. In the light of recent extensive research, we re-investigate the association between diabetes-associated metabolic disturbances (IR, subclinical inflammation, dyslipidemia, hyperglycemia, dysregulated production of adipokines, defective incretin and gut hormones production/action, and oxidative stress) and ED, focusing on oxidative stress and endothelial progenitor cells (EPCs). In addition, we re-emphasize that oxidative stress is the final common pathway that transduces signals from other conditions-either directly or indirectly-leading to ED and CVD.

Circulating resistin protein and mRNA concentrations and clinical severity of coronary artery disease

INTRODUCTION

Previous studies have implicated a strong link between circulating plasma resistin and coronary artery disease (CAD). The aim of this study was to evaluate the differences in peripheral blood mononuclear cells (PBMC) resistin mRNA and its plasma protein concentrations between the patients with CAD of different clinical severity.

MATERIAL AND METHODS

This study included 33 healthy subjects as the control group (CG) and 77 patients requiring coronary angiography. Of the latter 30 was CAD negative whereas 47 were CAD positive [18 with stable angina pectoris (SAP) and 29 with acute coronary syndrome (ACS)]. Circulating resistin was measured by ELISA; PBMC resistin mRNA was determined by real-time PCR.

RESULTS

Resistin protein was significantly higher in the ACS group compared to the CG (P=0.001) and the CAD negative group (P=0.018). Resistin mRNA expression did not vary across the study groups, despite the positive correlation seen with plasma resistin (ρ=0.305, P=0.008). In patients, plasma resistin and PBMC resistin mRNA negatively correlated with HDL-C (ρ=-0.404, P<0.001 and ρ=-0.257, P=0.032, respectively). Furthermore, the highest plasma resistin tertile showed the lowest HDL-C (P=0.006). Plasma resistin was positively associated with serum creatinine (ρ=0.353, P=0.002).

CONCLUSION

Significant increase of plasma resistin in patients with ACS compared to CG and CAD negative patients was observed. Despite no change in PBMC resistin mRNA in different disease conditions a positive association between resistin mRNA and resistin plasma protein was evident. Both plasma resistin and PBMC resistin mRNA were negatively associated with plasma HDL-C, and plasma resistin positively with serum creatinine.

Ictal adipokines are associated with pain severity and treatment response in episodic migraine

OBJECTIVE

To evaluate ictal adipokine levels in episodic migraineurs and their association with pain severity and treatment response.

METHODS

This was a double-blind, placebo-controlled trial evaluating peripheral blood specimens from episodic migraineurs at acute pain onset and 30 to 120 minutes after treatment with sumatriptan/naproxen sodium vs placebo. Total adiponectin (T-ADP), ADP multimers (high molecular weight [HMW], middle molecular weight, and low molecular weight [LMW]), leptin, and resistin levels were evaluated by immunoassays.

RESULTS

Thirty-four participants (17 responders, 17 nonresponders) were included. In all participants, pretreatment pain severity increased with every quartile increase in both the HMW:T-ADP ratio (coefficient of variation [CV] 0.51; 95% confidence interval [CI]: 0.08, 0.93; p = 0.019) and resistin levels (CV 0.58; 95% CI: 0.21, 0.96; p = 0.002), but was not associated with quartile changes in leptin levels. In responders, T-ADP (CV -0.98; 95% CI: -1.88, -0.08; p = 0.031) and resistin (CV -0.95; 95% CI: -1.83, -0.07; p = 0.034) levels decreased 120 minutes after treatment as compared with pretreatment. In addition, in responders, the HMW:T-ADP ratio (CV -0.04; 95% CI: -0.07, -0.01; p = 0.041) decreased and the LMW:T-ADP ratio (CV 0.04; 95% CI: 0.01, 0.07; p = 0.043) increased at 120 minutes after treatment. In nonresponders, the LMW:T-ADP ratio (CV -0.04; 95% CI: -0.07, -0.01; p = 0.018) decreased 120 minutes after treatment. Leptin was not associated with treatment response.

CONCLUSIONS

Both pretreatment migraine pain severity and treatment response are associated with changes in adipokine levels. Adipokines represent potential novel migraine biomarkers and drug targets.

Mn porphyrin-based SOD mimic, MnTnHex-2-PyP(5+), and non-SOD mimic, MnTBAP(3-), suppressed rat spinal cord ischemia/reperfusion injury via NF-κB pathways

Herein we have demonstrated that both superoxide dismutase (SOD) mimic, cationic Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin (MnTnHex-2-PyP(5+)), and non-SOD mimic, anionic Mn(III) meso-tetrakis(4-carboxylatophenyl)porphyrin (MnTBAP(3-)), protect against oxidative stress caused by spinal cord ischemia/reperfusion via suppression of nuclear factor kappa B (NF-κB) pro-inflammatory pathways. Earlier reports showed that Mn(III) N-alkylpyridylporphyrins were able to prevent the DNA binding of NF-κB in an aqueous system, whereas MnTBAP(3-) was not. Here, for the first time, in a complex in vivo system-animal model of spinal cord injury-a similar impact of MnTBAP(3-), at a dose identical to that of MnTnHex-2-PyP(5+), was demonstrated in NF-κB downregulation. Rats were treated subcutaneously at 1.5 mg/kg starting at 30 min before ischemia/reperfusion, and then every 12 h afterward for either 48 h or 7 days. The anti-inflammatory effects of both Mn porphyrins (MnPs) were demonstrated in the spinal cord tissue at both 48 h and 7 days. The downregulation of NF-κB, a major pro-inflammatory signaling protein regulating astrocyte activation, was detected and found to correlate well with the suppression of astrogliosis (as glial fibrillary acidic protein) by both MnPs. The markers of oxidative stress, lipid peroxidation and protein carbonyl formation, were significantly reduced by MnPs. The favorable impact of both MnPs on motor neurons (Tarlov score and inclined plane test) was assessed. No major changes in glutathione peroxidase- and SOD-like activities were demonstrated, which implies that none of the MnPs acted as SOD mimic. Increasing amount of data on the reactivity of MnTBAP(3-) with reactive nitrogen species (RNS) (.NO/HNO/ONOO(-)) suggests that RNS/MnTBAP(3-)-driven modification of NF-κB protein cysteines may be involved in its therapeutic effects. This differs from the therapeutic efficacy of MnTnHex-2-PyP(5+) which presumably occurs via reactive oxygen species and relates to NF-κB thiol oxidation; the role of RNS cannot be excluded.

Resistin: insulin resistance to malignancy

Adipose tissue is recognized as an endocrine organ that secretes bioactive substances known as adipokines. Excess adipose tissue and adipose tissue dysfunction lead to dysregulated adipokine production that can contribute to the development of obesity-related co-morbidities. Among the various adipokines, resistin, which was initially considered as a determinant of the emergence of insulin resistance in obesity, has appeared as an important link between obesity and inflammatory processes. Several experimental and clinical studies have suggested an association between increased resistin levels and severe conditions associated with obesity such as cardiovascular disease and malignancies. In this review, we present the growing body of evidence that human resistin is an inflammatory biomarker and potential mediator of obesity-associated diseases. A common pathway seems to involve the combined alteration of immune and inflammatory processes that favor metabolic disturbances, atherosclerosis and carcinogenesis. The mode of action and the signaling pathways utilized by resistin in its interactions with target cells could involve oxidative and nitrosative stress. Therefore, resistin could function as a key molecule in the complications of obesity development and could potentially be used as a diagnostic and prognostic marker.