WNT5A regulates adipose tissue angiogenesis via antiangiogenic VEGF-A165b in obese humans

Apigenin Self-Assembled Collagen Biomatrix for Reprogramming the Obese Wound Microenvironment for Its Management and Repair

Wound management in obesity is complicated by excessive exudates from wounded areas, pressure ulcerations due to stacking of the fat layer, and vascular rarefaction. The current study explored the development of biomaterials for reprogramming the altered wound microenvironment under obese conditions. Self-assembled collagen biomatrix with trans and de novo browning activator, apigenin, was fabricated as a soft tissue regenerative wound dressing material. The as-synthesized self-assembled collagen biomatrix exhibited excellent thermal, mechanical, and biological stability with a superior wound exudate absorption capacity. The apigenin self-assembled collagen biomatrix exhibited porous 3-D microstructure that mimicked the extracellular matrix that promoted cell adhesion and proliferation. The apigenin self-assembled collagen multifunctional biomatrix triggered adaptive localized thermogenesis in the subcutaneous fat layer, resulting in the activation of angiogenesis and fibroblast spreading and migration. The in vivo wound healing assay performed in DIO-C57BL6 mice showed faster tissue regeneration within 9 days, with well-defined neo-epidermis, blood vessel formation, thick collagen deposition, minimal inflammation, and significant activation of browning in the subcutaneous adipose layer. This study paves the way forward for the development of specialized regenerative biomatrices that reprogram the obese wound bed for faster tissue regeneration.

The evolving functions of the vasculature in regulating adipose tissue biology in health and obesity

Adipose tissue is an endocrine organ and a crucial regulator of energy storage and systemic metabolic homeostasis. Additionally, adipose tissue is a pivotal regulator of cardiovascular health and disease, mediated in part by the endocrine and paracrine secretion of several bioactive products, such as adipokines. Adipose vasculature has an instrumental role in the modulation of adipose tissue expansion, homeostasis and metabolism. The role of the adipose vasculature has been extensively explored in the context of obesity, which is recognized as a global health problem. Obesity-induced accumulation of fat, in combination with vascular rarefaction, promotes adipocyte dysfunction and induces oxidative stress, hypoxia and inflammation. It is now recognized that obesity-associated endothelial dysfunction often precedes the development of cardiovascular diseases. Investigations have revealed heterogeneity within the vascular niche and dynamic reciprocity between vascular and adipose cells, which can become dysregulated in obesity. Here we provide a comprehensive overview of the evolving functions of the vasculature in regulating adipose tissue biology in health and obesity.

Generation of Connective Tissue-Free Microvascular Fragment Isolates from Subcutaneous Fat Tissue of Obese Mice

BACKGROUND

Microvascular fragment (MVF) isolates are generated by short-term enzymatic digestion of adipose tissue and contain numerous vessel segments for the vascularization of tissue defects. Recent findings indicate that the functionality of these isolates is determined by the quality of the fat source. Therefore, we compared MVF isolates from subcutaneous adipose tissue of obese and lean mice.

METHODS

MVF isolates were generated from subcutaneous adipose tissue of donor mice, which received a high fat or control diet for 12 weeks. The isolates were analyzed in vitro and in vivo.

RESULTS

Feeding of mice with a high fat diet induced obesity with adipocyte hypertrophy, resulting in a significantly lower collagen fraction and microvessel density within the subcutaneous fat depots when compared to lean controls. Accordingly, MVF isolates from obese mice also contained a reduced number of MVF per mL adipose tissue. However, these MVF tended to be longer and, in contrast to MVF from lean mice, were not contaminated with collagen fibers. Hence, they could be freely seeded onto collagen-glycosaminoglycan scaffolds, whereas MVF from lean controls were trapped in between large amounts of collagen fibers that clogged the pores of the scaffolds. In line with these results, scaffolds seeded with MVF isolates from obese mice exhibited a significantly improved in vivo vascularization after implantation into full-thickness skin defects.

CONCLUSION

Subcutaneous adipose tissue from obese mice facilitates the generation of connective tissue-free MVF isolates. Translated to clinical conditions, these findings suggest that particularly obese patients may benefit from MVF-based vascularization strategies.

Pathological angiogenesis: mechanisms and therapeutic strategies

In multicellular organisms, angiogenesis, the formation of new blood vessels from pre-existing ones, is an essential process for growth and development. Different mechanisms such as vasculogenesis, sprouting, intussusceptive, and coalescent angiogenesis, as well as vessel co-option, vasculogenic mimicry and lymphangiogenesis, underlie the formation of new vasculature. In many pathological conditions, such as cancer, atherosclerosis, arthritis, psoriasis, endometriosis, obesity and SARS-CoV-2(COVID-19), developmental angiogenic processes are recapitulated, but are often done so without the normal feedback mechanisms that regulate the ordinary spatial and temporal patterns of blood vessel formation. Thus, pathological angiogenesis presents new challenges yet new opportunities for the design of vascular-directed therapies. Here, we provide an overview of recent insights into blood vessel development and highlight novel therapeutic strategies that promote or inhibit the process of angiogenesis to stabilize, reverse, or even halt disease progression. In our review, we will also explore several additional aspects (the angiogenic switch, hypoxia, angiocrine signals, endothelial plasticity, vessel normalization, and endothelial cell anergy) that operate in parallel to canonical angiogenesis mechanisms and speculate how these processes may also be targeted with anti-angiogenic or vascular-directed therapies.

Hypoxia as a Double-Edged Sword to Combat Obesity and Comorbidities

The global epidemic of obesity is tightly associated with numerous comorbidities, such as type II diabetes, cardiovascular diseases and the metabolic syndrome. Among the key features of obesity, some studies have suggested the abnormal expansion of adipose-tissue-induced local endogenous hypoxic, while other studies indicated endogenous hyperoxia as the opposite trend. Endogenous hypoxic aggravates dysfunction in adipose tissue and stimulates secretion of inflammatory molecules, which contribute to obesity. In contrast, hypoxic exposure combined with training effectively generate exogenous hypoxic to reduce body weight and downregulate metabolic risks. The (patho)physiological effects in adipose tissue are distinct from those of endogenous hypoxic. We critically assess the latest advances on the molecular mediators of endogenous hypoxic that regulate the dysfunction in adipose tissue. Subsequently we propose potential therapeutic targets in adipose tissues and the small molecules that may reverse the detrimental effect of local endogenous hypoxic. More importantly, we discuss alterations of metabolic pathways in adipose tissue and the metabolic benefits brought by hypoxic exercise. In terms of therapeutic intervention, numerous approaches have been developed to treat obesity, nevertheless durability and safety remain the major concern. Thus, a combination of the therapies that suppress endogenous hypoxic with exercise plans that augment exogenous hypoxic may accelerate the development of more effective and durable medications to treat obesity and comorbidities.

Angiogenesis in adipose tissue and obesity

While most tissues exhibit their greatest growth during development, adipose tissue is capable of additional massive expansion in adults. Adipose tissue expandability is advantageous when temporarily storing fuel for use during fasting, but becomes pathological upon continuous food intake, leading to obesity and its many comorbidities. The dense vasculature of adipose tissue provides necessary oxygen and nutrients, and supports delivery of fuel to and from adipocytes under fed or fasting conditions. Moreover, the vasculature of adipose tissue comprises a major niche for multipotent progenitor cells, which give rise to new adipocytes and are necessary for tissue repair. Given the multiple, pivotal roles of the adipose tissue vasculature, impairments in angiogenic capacity may underlie obesity-associated diseases such as diabetes and cardiometabolic disease. Exciting new studies on the single-cell and single-nuclei composition of adipose tissues in mouse and humans are providing new insights into mechanisms of adipose tissue angiogenesis. Moreover, new modes of intercellular communication involving micro vesicle and exosome transfer of proteins, nucleic acids and organelles are also being recognized to play key roles. This review focuses on new insights on the cellular and signaling mechanisms underlying adipose tissue angiogenesis, and on their impact on obesity and its pathophysiological consequences.

Measurement of Revascularization in the Hind Limb After Experimental Ischemia in Mice

Peripheral vascular disease is a major cause of morbidity and mortality, and is a consequence of impaired blood flow to the limbs. This arises due to the inability of the tissue to develop sufficiently functional collateral vessel circulation to overcome occluded arteries, or microvascular impairment. The mouse hind limb model of hind limb ischemia can be used to investigate the impact of different treatment modalities, behavioral changes, or genetic knockout. Here we described the model in detail, providing examples of adverse events, and details of ex vivo analysis of blood vessel density.

Exercise training modulates adipokines dysregulations in metabolic syndrome

Metabolic syndrome (MetS) is a cluster of risk factors for various metabolic diseases, and it is characterized by central obesity, dyslipidemia, hypertension, and insulin resistance. The core component for MetS is adipose tissue, which releases adipokines and influences physical health. Adipokines consist of pro and anti-inflammatory cytokines and contribute to various physiological functions. Generally, a sedentary lifestyle promotes fat accumulation and secretion of pro-inflammatory adipokines. However, regular exercise has been known to exert various beneficial effects on metabolic and cognitive disorders. Although the mechanisms underlying exercise beneficial effects in MetS are not fully understood, changes in energy expenditure, fat accumulation, circulatory level of myokines, and adipokines might be involved. This review article focuses on some of the selected adipokines in MetS, and their responses to exercise training considering possible mechanisms.

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Adipokines are a potential link between visceral fats and complications of MetS.

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Physical inactivity increases pro-inflammatory adipokines.

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Moderate aerobic exercise increases anti-inflammatory adipokines partly via reducing adipose tissue mass.

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Physical exercise-induced myokines might mediate beneficial effects via a cross-talk with adipose tissues.

Possible role of WNT10B in increased proliferation and tubule formation of human umbilical vein endothelial cell cultures treated with hypoxic conditioned medium from human adipocytes

Regulation of angiogenesis plays an important role in adipose tissue expansion and function. The Wnt pathway and WNT10B, the main member of Wnt family, participate in angiogenesis in cancer tumors, but there is limited evidence to support the regulatory role of WNT10B in human adipose tissue angiogenesis. Subcutaneous white adipose tissue (scWAT) of 80 participants including obese and non-obese subjects was obtained and the expression of WNT10B and VEGFA genes were evaluated using qPCR. Human adipose-derived stem cells (hADSC) were differentiated to adipocytes and incubated under either hypoxic or normoxic conditions. The conditioned media of these adipocytes were collected and used as growth media for human umbilical vein endothelial cells (HUVEC) in Matrigel. We evaluated the proliferation, cell cycle phases, tubule formation and β-catenin activation of these treated cells. We found a significant correlation between WNT10B and VEGFA expression in the scWAT of both obese and non-obese subjects. Proliferation and tubule formation of HUVEC treated with conditioned media of hypoxic adipocytes (hCM) in the S-phase were increased significantly compared to the HUVEC treated with the conditioned media of normoxic adipocytes (nCM). The expression of WNT10B and VEGFA was enhanced in hypoxic adipocytes compared to normoxic adipocytes; also, activation and nuclear translocation of β-catenin was enhanced in the HUVEC treated with hCM compared to nCM. WNT10B acts as an angiogenic protein in scWAT under hypoxic conditions. Hypoxia induced WNT10B increases VEGFA expression and causes tube formation by HUVECs and angiogenesis in adipose tissue via the canonical Wnt/β-catenin pathway.

Loss of m6A demethylase ALKBH5 promotes post-ischemic angiogenesis via post-transcriptional stabilization of WNT5A

BACKGROUND

Post-ischemic angiogenesis is critical for blood flow recovery and ischemic tissue repair. N6-methyladenosine (m6A) plays essential roles in numerous biological processes. However, the impact and connected mechanism of m6A on post-ischemic angiogenesis are not fully understood.

METHODS

AlkB homolog 5 (ALKBH5) was screened out among several methyltransferases and demethylases involved in dynamic m6A regulation. Cardiac microvascular endothelial cells (CMECs) angiogenesis and WNT family member 5A (WNT5A) stability were analyzed upon ALKBH5 overexpression with adenovirus or knockdown with small interfering RNAs in vitro. The blood flow recovery, capillary, and small artery densities were evaluated in adeno-associated virus (AAV)-ALKBH5 overexpression or ALKBH5 knockout (KO) mice in a hind-limb ischemia model. The same experiments were conducted to explore the translational value of transient silencing of ALKBH5 with adenovirus.

RESULTS

ALKBH5 was significantly upregulated in hypoxic CMECs and led to a global decrease of m6A level. ALKBH5 overexpression further reduced m6A level in normoxic and hypoxic CMECs, impaired proliferation, migration, and tube formation only in hypoxic CMECs. Conversely, ALKBH5 knockdown preserved m6A levels and promoted angiogenic phenotypes in hypoxic but not in normoxic CMECs. Mechanistically, ALKBH5 regulated WNT5A expression through post-transcriptional mRNA modulation in an m6A-dependent manner, which decreased its stability and subsequently impeded angiogenesis in hypoxic CMECs. Furthermore, ALKBH5 overexpression hindered blood flow recovery and reduced CD31 and alpha-smooth muscle actin expression in hind-limb ischemia mice. As expected, ALKBH5-KO mice exhibited improved blood flow recovery, increased capillary, and small artery densities after hind-limb ischemia, and similar beneficial effects were observed in mice with transient adenoviral ALKBH5 gene silencing.

CONCLUSION

We demonstrate that ALKBH5 is a negative regulator of post-ischemic angiogenesis via post-transcriptional modulation and destabilization of WNT5A mRNA in an m6A-dependent manner. Targeting ALKBH5 may be a potential therapeutic option for ischemic diseases, including peripheral artery disease.

Perivascular Adipose Tissue Inflammation in Ischemic Heart Disease

OBJECTIVE

There is growing recognition that adipose tissue-derived proatherogenic mediators contribute to obesity-related cardiovascular disease. We sought to characterize regional differences in perivascular adipose tissue (PVAT) phenotype in relation to atherosclerosis susceptibility. Approach and Results: We examined thoracic PVAT samples in 34 subjects (body mass index 32±6 kg/m², age 59±11 years) undergoing valvular, aortic, or coronary artery bypass graft surgeries and performed transcriptomic characterization using whole-genome expression profiling and quantitative polymerase chain reaction analyses. We identified a highly inflamed region of PVAT surrounding the human aortic root in close proximity to coronary takeoff and adjoining epicardial fat. In subjects undergoing coronary artery bypass graft, we found 300 genes significantly upregulated (false discovery rate Q<0.1) in paired samples of PVAT surrounding the aortic root compared with nonatherosclerotic left internal mammary artery. Genes encoding proteins mechanistically implicated in atherogenesis were enriched in aortic PVAT consisting of signaling pathways linked to inflammation, WNT (wingless-related integration site) signaling, matrix remodeling, coagulation, and angiogenesis. Overexpression of several proatherogenic transcripts, including IL1β, CCL2 (MCP-1), and IL6, were confirmed by quantitative polymerase chain reaction and significantly bolstered in coronary artery disease subjects. Angiographic coronary artery disease burden quantified by the Gensini score positively correlated with the expression of inflammatory genes in PVAT. Moreover, periaortic adipose inflammation was markedly higher in obese subjects with striking upregulation (≈8-fold) of IL1β expression compared to nonobese individuals.

CONCLUSIONS

Proatherogenic mediators that originate from dysfunctional PVAT may contribute to vascular disease mechanisms in human vessels. Moreover, PVAT may adopt detrimental properties under obese conditions that play a key role in the pathophysiology of ischemic heart disease. Graphic Abstract: A graphic abstract is available for this article.

Capillary Rarefaction in Obesity and Metabolic Diseases-Organ-Specificity and Possible Mechanisms

Obesity and its comorbidities like diabetes, hypertension and other cardiovascular disorders are the leading causes of death and disability worldwide. Metabolic diseases cause vascular dysfunction and loss of capillaries termed capillary rarefaction. Interestingly, obesity seems to affect capillary beds in an organ-specific manner, causing morphological and functional changes in some tissues but not in others. Accordingly, treatment strategies targeting capillary rarefaction result in distinct outcomes depending on the organ. In recent years, organ-specific vasculature and endothelial heterogeneity have been in the spotlight in the field of vascular biology since specialized vascular systems have been shown to contribute to organ function by secreting varying autocrine and paracrine factors and by providing niches for stem cells. This review summarizes the recent literature covering studies on organ-specific capillary rarefaction observed in obesity and metabolic diseases and explores the underlying mechanisms, with multiple modes of action proposed. It also provides a glimpse of the reported therapeutic perspectives targeting capillary rarefaction. Further studies should address the reasons for such organ-specificity of capillary rarefaction, investigate strategies for its prevention and reversibility and examine potential signaling pathways that can be exploited to target it.

High preoperative levels of circulating SFRP5 predict better prognosis in colorectal cancer patients

The purpose of this research was to investigate the diagnostic and prognostic value of circulating SFRP5 (cSFRP5) in colorectal cancer (CRC). We evaluated preoperative cSFRP5 levels in CRC patients and controls (n = 208). We found significantly higher cSFRP5 levels in CRC patients compared with non-CRC controls (p < 0.001). Levels of cSFRP5 were significantly lower in CRC patients with either vascular invasion (p = 0.001) or liver metastasis (p = 0.016). High cSFRP5 levels were associated with longer disease-free survival in both univariate (p = 0.024) and multivariate (p = 0.015) analyses. Analysis of an independent tissue cohort from The Cancer Genome Atlas database revealed significantly lower SFRP5 RNA expression in CRC tumor tissue compared with adjacent normal mucosa (n = 590 vs 47; p < 0.0001). Our findings confirm the role of cSFRP5 as a physiologic tumor suppressor and demonstrate its potential diagnostic and prognostic value in CRC.

Particulate matter (PM10) induces cardiovascular developmental toxicity in zebrafish embryos and larvae via the ERS, Nrf2 and Wnt pathways

Particulate matter (PM10) is one of the most important indicators of the pollution that characterizes air quality. Epidemiological studies have shown that PM10 can cause cardiovascular-related diseases in the population. And, we studied the developmental toxicity of PM10 and the underlying mechanism of its effects on the cardiovascular system of zebrafish embryo/larva. Changes in cardiac morphology, sinus venosus and bulbus arteriosus (SV-BA) distance, heart rate, vascular subintestinalis, blood flow, returned blood volume, and reactive oxygen species (ROS) level were measured, and changes in the expression levels of certain genes were assessed via RT-PCR. The results showed that PM10 caused a significant increase in pericardial sac area and SV-BA distance, a decrease in heart rate, inhibition of vascular subintestinalis growth, blood flow obstruction, reduced venous return, and other cardiovascular toxicities. PM10 induced an increase in the ROS level and significant increases in the expression levels of ERS signalling pathway factors and Nrf2 signalling pathway factors. The expression levels of the Wnt pathway-related genes also showed significant changes. Furthermore, ROS inhibitor N-Acetyl-l-cysteine (NAC) could ameliorate the cardiovascular toxicity of PM10 in zebrafish larvae. It is speculated that PM10 may result in cardiovascular toxicity by inducing higher ROS levels in the body, which could then induce ERS and lead to defects in the expression of genes related to the Wnt signalling pathway. The Nrf2 signalling pathway was activated as a stress compensatory mechanism during the early stage of PM10-induced cardiovascular injury. However, it was insufficient to counteract the PM10-induced cardiovascular toxicity.

Immunometabolism: new insights and lessons from antigen-directed cellular immune responses

Modulation of immune responses by nutrients is an important area of study in cellular biology and clinical sciences in the context of cancer therapies and anti-pathogen-directed immune responses in health and disease. We review metabolic pathways that influence immune cell function and cellular persistence in chronic infections. We also highlight the role of nutrients in altering the tissue microenvironment with lessons from the tumor microenvironment that shapes the quality and quantity of cellular immune responses. Multiple layers of biological networks, including the nature of nutritional supplements, the genetic background, previous exposures, and gut microbiota status have impact on cellular performance and immune competence against molecularly defined targets. We discuss how immune metabolism determines the differentiation pathway of antigen-specific immune cells and how these insights can be explored to devise better strategies to strengthen anti-pathogen-directed immune responses, while curbing unwanted, non-productive inflammation.

Different effects of Wnt/β-catenin activation and PTH activation in adult and aged male mice metaphyseal fracture healing

Background

Fractures in older men are not uncommon and need to be healed as soon as possible to avoid related complications. Anti-osteoporotic drugs targeting Wnt/β-catenin and PTH (parathyroid hormone) to promote fracture healing have become an important direction in recent years. The study is to observe whether there is a difference in adult and aged situations by activating two signal paths.

Methods

A single cortical hole with a diameter of 0.6 mm was made in the femoral metaphysis of Catnb^lox(ex3) mice and wild-type mice. The fracture healing effects of CA (Wnt/β-catenin activation) and PTH (activated by PTH (1–34) injections) were assessed by X-ray and CT imaging on days 7, 14, and 21 after fracture. The mRNA levels of β-catenin, PTH1R(Parathyroid hormone 1 receptor), and RUNX2(Runt-related transcription factor 2) in the fracture defect area were detected using RT-PCR. Angiogenesis and osteoblasts were observed by immunohistochemistry and osteoclasts were observed by TRAP (Tartrate-resistant Acid Phosphatase).

Result

Adult CA mice and adult PTH mice showed slightly better fracture healing than adult wild-type (WT) mice, but there was no statistical difference. Aged CA mice showed better promotion of angiogenesis and osteoblasts and better fracture healing than aged PTH mice.

Conclusion

The application of Wnt/β-catenin signaling pathway drugs for fracture healing in elderly patients may bring better early effects than PTH signaling pathway drugs, but the long-term effects need to be observed.

Beyond adiponectin and leptin: adipose tissue-derived mediators of inter-organ communication

The breakthrough discoveries of leptin and adiponectin more than two decades ago led to a widespread recognition of adipose tissue as an endocrine organ. Many more adipose tissue-secreted signaling mediators (adipokines) have been identified since then, and much has been learned about how adipose tissue communicates with other organs of the body to maintain systemic homeostasis. Beyond proteins, additional factors, such as lipids, metabolites, noncoding RNAs, and extracellular vesicles (EVs), released by adipose tissue participate in this process. Here, we review the diverse signaling mediators and mechanisms adipose tissue utilizes to relay information to other organs. We discuss recently identified adipokines (proteins, lipids, and metabolites) and briefly outline the contributions of noncoding RNAs and EVs to the ever-increasing complexities of adipose tissue inter-organ communication. We conclude by reflecting on central aspects of adipokine biology, namely, the contribution of distinct adipose tissue depots and cell types to adipokine secretion, the phenomenon of adipokine resistance, and the capacity of adipose tissue to act both as a source and sink of signaling mediators.

Wnt5a-Mediated Neutrophil Recruitment Has an Obligatory Role in Pressure Overload-Induced Cardiac Dysfunction

BACKGROUND

Although the complex roles of macrophages in myocardial injury are widely appreciated, the function of neutrophils in nonischemic cardiac pathology has received relatively little attention.

METHODS

To examine the regulation and function of neutrophils in pressure overload-induced cardiac hypertrophy, mice underwent treatment with Ly6G antibody to deplete neutrophils and then were subjected to transverse aortic constriction.

RESULTS

Neutrophil depletion diminished transverse aortic constriction-induced hypertrophy and inflammation and preserved cardiac function. Myeloid deficiency of Wnt5a, a noncanonical Wnt, suppressed neutrophil infiltration to the hearts of transverse aortic constriction-treated mice and produced a phenotype that was similar to the neutropenic conditions. Conversely, mice overexpressing Wnt5a in myeloid cells displayed greater hypertrophic growth, inflammation, and cardiac dysfunction. Neutrophil depletion reversed the Wnt5a overexpression-induced cardiac pathology and eliminated differences in cardiac parameters between wild-type and myeloid-specific Wnt5a transgenic mice.

CONCLUSIONS

These findings reveal that Wnt5a-regulated neutrophil infiltration has a critical role in pressure overload-induced heart failure.

Fat-Specific Protein 27 Regulation of Vascular Function in Human Obesity

Background Pathophysiological mechanisms that connect obesity to cardiovascular disease are incompletely understood. FSP27 (Fat-specific protein 27) is a lipid droplet-associated protein that regulates lipolysis and insulin sensitivity in adipocytes. We unexpectedly discovered extensive FSP27 expression in human endothelial cells that is downregulated in association with visceral obesity. We sought to examine the functional role of FSP27 in the control of vascular phenotype. Methods and Results We biopsied paired subcutaneous and visceral fat depots from 61 obese individuals (body mass index 44±8 kg/m2, age 48±4 years) during planned bariatric surgery. We characterized depot-specific FSP27 expression in relation to adipose tissue microvascular insulin resistance, endothelial function and angiogenesis, and examined differential effects of FSP27 modification on vascular function. We observed markedly reduced vasodilator and angiogenic capacity of microvessels isolated from the visceral compared with subcutaneous adipose depots. Recombinant FSP27 and/or adenoviral FSP27 overexpression in human tissue increased endothelial nitric oxide synthase phosphorylation and nitric oxide production, and rescued vasomotor and angiogenic dysfunction (P<0.05), while siRNA-mediated FSP27 knockdown had opposite effects. Mechanistically, we observed that FSP27 interacts with vascular endothelial growth factor-A and exerts robust regulatory control over its expression. Lastly, in a subset of subjects followed longitudinally for 12±3 months after their bariatric surgery, 30% weight loss improved metabolic parameters and increased angiogenic capacity that correlated positively with increased FSP27 expression (r=0.79, P<0.05). Conclusions Our data strongly support a key role and functional significance of FSP27 as a critical endogenous modulator of human microvascular function that has not been previously described. FSP27 may serve as a previously unrecognized regulator of arteriolar vasomotor capacity and angiogenesis which are pivotal in the pathogenesis of cardiometabolic diseases linked to obesity.

Hyperlipidemias and Obesity

The organs require oxygen and other types of nutrients (amino acids, sugars, and lipids) to function, the heart consuming large amounts of fatty acids for oxidation and adenosine triphosphate (ATP) generation.

Impaired Adipogenesis and Dysfunctional Adipose Tissue in Human Hypertrophic Obesity

The subcutaneous adipose tissue (SAT) is the largest and best storage site for excess lipids. However, it has a limited ability to expand by recruiting and/or differentiating available precursor cells. When inadequate, this leads to a hypertrophic expansion of the cells with increased inflammation, insulin resistance, and a dysfunctional prolipolytic tissue. Epi-/genetic factors regulate SAT adipogenesis and genetic predisposition for type 2 diabetes is associated with markers of an impaired SAT adipogenesis and development of hypertrophic obesity also in nonobese individuals. We here review mechanisms for the adipose precursor cells to enter adipogenesis, emphasizing the role of bone morphogenetic protein-4 (BMP-4) and its endogenous antagonist gremlin-1, which is increased in hypertrophic SAT in humans. Gremlin-1 is a secreted and a likely important mechanism for the impaired SAT adipogenesis in hypertrophic obesity. Transiently increasing BMP-4 enhances adipogenic commitment of the precursor cells while maintained BMP-4 signaling during differentiation induces a beige/brown oxidative phenotype in both human and murine adipose cells. Adipose tissue growth and development also requires increased angiogenesis, and BMP-4, as a proangiogenic molecule, may also be an important feedback regulator of this. Hypertrophic obesity is also associated with increased lipolysis. Reduced lipid storage and increased release of FFA by hypertrophic SAT are important mechanisms for the accumulation of ectopic fat in the liver and other places promoting insulin resistance. Taken together, the limited expansion and storage capacity of SAT is a major driver of the obesity-associated metabolic complications.

LncRNA NEAT1 facilitates survival and angiogenesis in oxygen-glucose deprivation (OGD)-induced brain microvascular endothelial cells (BMECs) via targeting miR-377 and upregulating SIRT1, VEGFA, and BCL-XL

OBJECTIVE

The present study was designed to investigate the mechanism by which lncRNA NEAT1 regulates survival and angiogenesis in oxygen-glucose deprivation (OGD)-induced brain microvascular endothelial cells (BMECs).

METHODS

OGD-treated BMECs were used to mimic cerebral ischaemia in vitro. The expression of lncRNA NEAT1 and miR-377 and proteins including VEGFA, SIRT1, and BCL-XL were measured by real-time quantitative PCR (qRT-PCR) and western blot, respectively. Cell viability and caspase 3 activity of BMECs under different conditions were determined using MTT and caspase activity assays, respectively. Matrigel-based angiogenesis assays were employed to evaluate the effect of lncRNA NEAT1 on angiogenesis. A dual-luciferase reporter assay was used to validate direct binding of miR-377 to putative targets.

RESULTS

OGD exposure reduced the cell viability of BMECs. Upregulation of lncRNA NEAT1 and downregulation of miR-377 were also observed under OGD conditions. Knockdown of lncRNA NEAT1 inhibited angiogenesis and aggravated apoptosis in OGD-induced BMECs. Meanwhile, the expression level of miR-377 was upregulated while its downstream targets (VEGFA, SIRT1, and BCL-XL) were downregulated after lncRNA NEAT1 knockdown. Furthermore, miR-377 inhibited the angiogenesis and survival of OGD-induced BMECs. The expression of VEGFA, SIRT1, and BCL-XL were all attenuated by miR-377 overexpression. The dual-luciferase reporter assay proved miR-377 targeted the 3' UTR sequences of lncRNA NEAT1, VEGFA, SIRT1, and BCL-XL.

CONCLUSION

lncRNA NEAT1 facilitated the survival and angiogenesis of OGD-induced BMECs via targeting miR-377 and promoting the expression of VEGFA, SIRT1, and BCL-XL, suggesting that lncRNA NEAT1 could be a promising target for cerebral ischaemia treatment.

High-fat diet leads to adiposity and adipose tissue inflammation: the effect of whey protein supplementation and aerobic exercise training

There is little understanding about dietary proteins and their potential contribution to obesity-induced inflammation. This study investigates the effect of 10 weeks of aerobic training and whey protein (WP) supplementation on visceral adipose tissue inflammation in rats fed a high-fat diet (HFD). In the first phase, which lasted 9 weeks, 40 male Wistar rats were randomly divided into 2 groups: (1) normal diet (n = 8), and (2) HFD (n = 32). In the second phase, rats fed an HFD were randomly assigned into 4 groups (n = 8/group): (1) sedentary, (2) WP, (3) aerobic training, and (4) WP + aerobic training. The aerobic training was performed for 10 weeks, 5 days/week at 21 m/min, 15% incline, for 60 min/day. HFD significantly increased body weight, adiposity index, fat pads weight, glucose levels, and insulin resistance index compared with the normal diet. Also, levels of tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), hypoxia inducible factor 1 alpha (HIF-1α), and vascular endothelial growth factor A (VEGF-A) in adipose tissue and serum levels of TNF-α were increased in the HFD group. Glucose levels, insulin resistance index, and triglycerides were reduced only by WP, independently of aerobic training. Both the aerobic training and WP reduced the fat pads weight and levels of TNF-α, HIF-1α, and VEGF-A in adipose tissue. Nevertheless, the levels of MCP-1 in adipose tissue and serum levels of TNF-α and MCP-1 were not reduced significantly by WP or aerobic training. These findings suggest that both aerobic training and WP supplementation lead to a reduction in adiposity and ameliorate obesity-induced inflammation in visceral adipose tissue.

Statistical considerations in reporting cardiovascular research

The problem of inadequate statistical reporting is long standing and widespread in the biomedical literature, including in cardiovascular physiology. Although guidelines for reporting statistics have been available in clinical medicine for some time, there are currently no guidelines specific to cardiovascular physiology. To assess the need for guidelines, we determined the type and frequency of statistical tests and procedures currently used in the American Journal of Physiology-Heart and Circulatory Physiology. A PubMed search for articles published in the American Journal of Physiology-Heart and Circulatory Physiology between January 1, 2017, and October 6, 2017, provided a final sample of 146 articles evaluated for methods used and 38 articles for indepth analysis. The t-test and ANOVA accounted for 71% (212 of 300 articles) of the statistical tests performed. Of six categories of post hoc tests, Bonferroni and Tukey tests were used in 63% (62 of 98 articles). There was an overall lack in details provided by authors publishing in the American Journal of Physiology-Heart and Circulatory Physiology, and we compiled a list of recommended minimum reporting guidelines to aid authors in preparing manuscripts. Following these guidelines could substantially improve the quality of statistical reports and enhance data rigor and reproducibility.

Guidelines for authors and reviewers on antibody use in physiology studies

Antibody use is a critical component of cardiovascular physiology research, and antibodies are used to monitor protein abundance (immunoblot analysis) and protein expression and localization (in tissue by immunohistochemistry and in cells by immunocytochemistry). With ongoing discussions on how to improve reproducibility and rigor, the goal of this review is to provide best practice guidelines regarding how to optimize antibody use for increased rigor and reproducibility in both immunoblot analysis and immunohistochemistry approaches.

Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/guidelines-on-antibody-use-in-physiology-studies/.

Activation of non-canonical WNT signaling in human visceral adipose tissue contributes to local and systemic inflammation

The accumulation of visceral adiposity is strongly associated with systemic inflammation and increased cardiometabolic risk. WNT5A, a non-canonical WNT ligand, has been shown to promote adipose tissue inflammation and insulin resistance in animal studies. Among other non-canonical pathways, WNT5A activates planar cell polarity (PCP) signaling. The current study investigated the potential contribution of non-canonical WNT5A/PCP signaling to visceral adipose tissue (VAT) inflammation and associated metabolic dysfunction in individuals with obesity. VAT and subcutaneous adipose tissue (SAT) samples obtained from subjects undergoing bariatric surgery were analyzed by qRT-PCR for expression of WNT/PCP genes. In vitro experiments were conducted with preadipocytes isolated from VAT and SAT biopsies. The expression of 23 out of 33 PCP genes was enriched in VAT compared to SAT. Strong positive expression correlations of individual PCP genes were observed in VAT. WNT5A expression in VAT, but not in SAT, correlated with indexes of JNK signaling activity, IL6, waist-to-hip ratio and hsCRP. In vitro, WNT5A promoted the expression of IL6 in human preadipocytes. In conclusion, elevated non-canonical WNT5A signaling in VAT contributes to the exacerbated IL-6 production in this depot and the low-grade systemic inflammation typically associated with visceral adiposity.

The Lymphatic Vasculature: Its Role in Adipose Metabolism and Obesity

Obesity is a key risk factor for metabolic and cardiovascular diseases, and although we understand the mechanisms regulating weight and energy balance, the causes of some forms of obesity remain enigmatic. Despite the well-established connections between lymphatics and lipids, and the fact that intestinal lacteals play key roles in dietary fat absorption, the function of the lymphatic vasculature in adipose metabolism has only recently been recognized. It is well established that angiogenesis is tightly associated with the outgrowth of adipose tissue, as expanding adipose tissue requires increased nutrient supply from blood vessels. Results supporting a crosstalk between lymphatic vessels and adipose tissue, and linking lymphatic function with metabolic diseases, obesity, and adipose tissue, also started to accumulate in the last years. Here we review our current knowledge of the mechanisms by which defective lymphatics contribute to obesity and fat accumulation in mouse models, as well as our understanding of the lymphatic-adipose tissue relationship.

Angiogenesis in metabolic-vascular disease

Angiogenesis, literally formation of new blood vessels, is the main process through which the vascular system expands during embryonic and postnatal development. Endothelial cells, which constitute the inner lining of all blood vessels, are typically in a quiescent state in the healthy adult organism. However, in vascular and metabolic diseases, the endothelium becomes unstable and dysfunctional. The resulting tissue hypoxia may thereby induce pathological angiogenesis, which is a hallmark of disease conditions like cancer or diabetic retinopathy. However, recent evidence suggests that angiogenesis is also a major player in the context of further metabolic diseases, especially in obesity. In particular, deregulated angiogenesis is linked with adipose tissue dysfunction and insulin resistance. On the other hand, signalling pathways, such as the PI3K pathway, may regulate metabolic activities in the endothelium. Endothelial cell metabolism emerges as an important regulator of angiogenesis. This review summarises the role of angiogenesis in metabolic-vascular disease, with specific focus on the role of angiogenesis in obesity-related metabolic dysfunction and on signaling pathways, especially PI3K, linking cell metabolism to endothelial function.