Increased serum level and impaired response to glucose fluctuation of asprosin is associated with type 2 diabetes mellitus

Asprosin: its function as a novel endocrine factor in metabolic-related diseases

BACKGROUND AND PURPOSE

Asprosin was discovered as a new endocrine hormone originating from fibrillin-1 cleavage that plays a crucial role in various metabolic-related diseases, such as obesity, nonalcoholic fatty liver disease (NAFLD), diabetes, polycystic ovary syndrome (PCOS), and cardiovascular diseases. The purpose of this review is to describe the recent advancements of asprosin.

METHOD

Narrative review.

RESULT

This comprehensive review explores its tissue-specific functions, focusing on white adipose tissue, liver, hypothalamus, testis, ovary, heart, pancreas, skeletal muscle, and kidney.

CONCLUSION

Asprosin is a multifaceted protein with tissue-specific roles in various physiological and pathological processes. Further research is needed to fully understand the mechanisms and potential of asprosin as a therapeutic target. These insights could provide new directions for treatments targeting metabolic-related diseases.

Effects of atypical antipsychotics on serum asprosin level and other metabolic parameters in patients with schizophrenia

BACKGROUND

In this cross-sectional study, we compared fasting serum asprosin levels and metabolic parameters between patients receiving one of three atypical antipsychotics (olanzapine, risperidone, or aripiprazole) and healthy subjects.

METHODS

The study population included 62 adult outpatients with schizophrenia and 22 healthy controls, matched for age and gender. Patients were in remission and had been on stable monotherapy with one of these atypical antipsychotics for over 6 months. Body Mass Index (BMI) and fasting serum levels of asprosin, glucose, HA1c, insulin, and lipid profile were compared across the investigated groups. Additionally, the number of participants meeting the insulin resistance criterion, defined as homeostasis model assessment for insulin resistance (HOMA-IR) >2.5, as well as the number of participants with elevated BMI levels (men >27 kg/m2, women >25 kg/m2) were compared among the groups.

RESULTS

We observed statistically significant differences in BMI and fasting serum levels of glucose, HA1c, insulin, triglyceride (TG), high-density lipoprotein cholesterol, and asprosin among patients receiving olanzapine or risperidone, as compared to those receiving aripiprazole and healthy subjects. Patients on aripiprazole exhibited values comparable to healthy subjects, whereas those on risperidone or olanzapine showed significantly higher values, with the highest observed in the olanzapine group. Additionally, the prevalence of participants meeting the insulin resistance criterion and those with elevated BMI was also greater in individuals receiving olanzapine or risperidone compared to those on aripiprazole and healthy subjects. Serum asprosin levels showed a significant positive correlation with BMI and several metabolic parameters, including HbA1c, fasting insulin, HOMA-IR, and TG. No significant differences were observed among the investigated groups in terms of serum levels of total cholesterol and low-density lipoprotein cholesterol.

CONCLUSIONS

Our cross-sectional study highlights the association between elevated asprosin levels, weight gain, and metabolic disorders in patients treated with olanzapine and risperidone. Given the bidirectional nature of the relationship between serum asprosin levels and these metabolic disturbances, further research is warranted to elucidate potential causative pathways.

Association of serum asprosin with metabolic dysfunction-associated fatty liver disease in older adult type 2 diabetic patients: a cross-sectional study

BACKGROUND

To explore the association of serum asprosin levels with metabolic dysfunction-associated fatty liver disease (MAFLD) in older adults with type 2 diabetes mellitus (T2DM).

METHODS

The cross-sectional study enrolled patients ≥ 65 years old diagnosed with T2DM at two community health service centers between November 2019 and July 2021. Logistic regression was applied to analyze the influencing factors of MAFLD.

RESULTS

Totally 219 cases were included. Compared with diabetic individuals without MAFLD (n = 105), diabetics with MAFLD (n = 114) had younger ages, higher body mass index values, shorter time from T2DM diagnosis, increased waist-to-hip ratios, elevated triglycerides, reduced high-density lipoprotein cholesterol (HDL-C), elevated alanine aminotransferase (ALT), elevated γ-glutaryl transferase, elevated fasting insulin, and elevated HOMA-IR (all P < 0.05). Serum asprosin levels were elevated in diabetics with MAFLD in comparison with the non-MAFLD group (291.71 ± 73.69 vs. 255.24 ± 82.52 pg/ml, P = 0.001). Multivariable analysis revealed, after adjusted for age, time from T2DM diagnosis, HDL-C, and ALT, serum asprosin level (OR = 1.006, 95%CI: 1.001-1.010, P = 0.014) were independently associated with MAFLD in T2DM.

CONCLUSIONS

High asprosin level are associated with MAFLD in older patients with T2DM, after adjusted for age, time from T2DM diagnosis, WHR, TG, HDL-C, ALT, GGT, FINS, and HOMA-IR.

The mediation effect of asprosin on the association between ambient air pollution and diabetes mellitus in the elderly population in Taiyuan, China

Evidence around the relationship between air pollution and the development of diabetes mellitus (DM) remains limited and inconsistent. To investigate the potential mediation effect of asprosin on the association between fine particulate matter (PM2.5), tropospheric ozone (O3) and blood glucose homeostasis. A case-control study was conducted on a total of 320 individuals aged over 60 years, including both diabetic and non-diabetic individuals, from six communities in Taiyuan, China, from July to September 2021. Generalized linear models (GLMs) suggested that short-term exposure to PM2.5 was associated with elevated fasting blood glucose (FBG), insulin resistance index (HOMA-IR), as well as reduced pancreatic β-cell function index (HOMA-β), and short-term exposure to O3 was associated with increased FBG and decreased HOMA-β in the total population and elderly diabetic patients. Mediation analysis showed that asprosin played a mediating role in the relationship of PM2.5 and O3 with FBG, with mediating ratios of 10.2% and 18.4%, respectively. Our study provides emerging evidence supporting that asprosin mediates the short-term effects of exposure to PM2.5 and O3 on elevated FBG levels in an elderly population. Additionally, the elderly who are diabetic, over 70 years, and BMI over 24 kg/m2 are more vulnerable to air pollutants and need additional protection to reduce their exposure to air pollution.

Whole-Body Cryotherapy Improves Asprosin Secretion and Insulin Sensitivity in Postmenopausal Women-Perspectives in the Management of Type 2 Diabetes

Type 2 diabetes (T2DM) is a global problem. The effect of whole-body cryotherapy (WBC) on metabolism in humans is postulated. The aim of this study was to determine the effect of WBC on asprosin concentrations, glucose homeostasis and insulin resistance in postmenopausal women with T2DM. Changes in fasting blood glucose (FBG), glycated haemoglobin (HbA1c), insulin, asprosin, insulin-resistance indices (HOMA-IR, Quicki), the triglyceride-glucose index (TyG) and C-reactive protein (CRP) were determined. Determination was carried out after 30 WBCs (3 min, -120 °C), applied in six series of five treatments, with 2-day breaks in postmenopausal women with T2DM and the results were compared to changes in postmenopausal women without T2DM (CON). Blood was collected before 1 WBC (T0), after 30 WBCs (T1) and 2 weeks after their completion (T2). In the T2DM group, there was a significant decrease in FBG and HbA1c in T1 and T2, as well as a significant decrease in insulin, HOMA-IR and CRP, and an increase in the Quicki index in T2. In the CON group, the concentration of asprosin at T2 was significantly lower than at T0. There was a significantly positive correlation between asprosin and FBG and HOMA-IR, and a trend towards a decrease of asprosin concentration in T2 in postmenopausal women with T2DM.

Asprosin, a novel glucogenic adipokine: a potential therapeutic implication in diabetes mellitus

OBJECTIVES

We aimed to investigate the effects of asprosin on diabetes with a focus on serum glucose, irisin, ghrelin, leptin levels and hepatic levels of triglycerides (TG), cholesterol, low-density lipoprotein (LDL).

METHODS

Asprosin (10 µg/kg) was administered intraperitoneally four times at 3-day intervals and then blood and hepatic parameters above mentioned were investigated in control and diabetic mice.

RESULTS

The administration of asprosin increased blood glucose level in healthy animals (p = .05) whereas it did not change blood glucose level in diabetic animals. In addition, while asprosin decreased irisin level and increased ghrelin level, it did not change leptin level in diabetic mice. Therewithal, asprosin decreased the increasing levels in hepatic TG, cholesterol, and LDL in diabetic mice.

CONCLUSIONS

Our novel findings implicate that asprosin may be a target molecule in preventing the development and complications of diabetes.

Meteorin-like Protein and Asprosin Levels in Children and Adolescents with Obesity and Their Relationship with Insulin Resistance and Metabolic Syndrome

OBJECTIVE

Two newly discovered adipokines, including Meteorin-like protein (Metrnl) and asprosin, have been implicated in glucose and insulin metabolism. This study aimed to investigate the associations of these adipokines with obesity in children and adolescents.

METHODS

This study was performed on 35 normal-weight children and 35 children with obesity. Anthropometric and biochemical parameters were determined. Serum concentrations of Metrnl, asprosin, and insulin were measured using enzyme-linked immunosorbent assay.

RESULTS

Metrnl level was significantly lower in obese children than normal-weight children. Additionally, Metrnl was negatively correlated with body mass index (BMI), insulin, waist-to-hip ratio, and homeostatic model assessment of insulin resistance (HOMA-IR). Our results also revealed that circulating asprosin levels were significantly increased in obese children compared to the control subjects and were positively correlated with BMI, insulin, HOMA-IR, cholesterol, and LDL-C.

CONCLUSION

Obesity is accompanied by significant alterations in Metrnl and asprosin and therefore these adipokines, especially Metrnl, are suggested as new promising therapeutic targets for obesity and its associated metabolic imbalances.

Can the new adipokine asprosin be a metabolic troublemaker for cardiovascular diseases? A state-of-the-art review

Adipokines play a significant role in cardiometabolic diseases. Asprosin, a newly discovered adipokine, was first identified as a glucose-raising protein hormone. Asprosin also stimulates appetite and regulates glucose and lipid metabolism. Its identified receptors so far include Olfr734 and Ptprd. Clinical studies have found that asprosin may be associated with cardiometabolic diseases. Asprosin may have diagnostic and therapeutic potential in obesity, diabetes, metabolic syndrome and atherosclerotic cardiovascular diseases. Herein, the structure, receptors, and functions of asprosin and its relationship with cardiometabolic diseases are summarized based on recent findings.

Correlation of Serum Asprosin Levels With Normalized Protein Catabolic Rate in Patients Receiving Peritoneal Dialysis Treatment

Background Peritoneal dialysis patients are malnourished due to loss of protein in the dialysate and inadequate dialysis, although they take additional calories every day during treatment. Many parameters are used to assess nutritional status, with normalized protein catabolic rate (nPCR) being one of the most common. Asprosin, a novel adipokine secreted by adipose tissue, peaks during fasting and induces hepatic glucose release through the activation of the G-protein-cAMP-PKA pathway, which has been indicated to have a curative effect on chronic inflammation. In this study, we aimed to investigate the relationship between asprosin levels and nutritional parameters in patients receiving peritoneal dialysis treatment as well as to investigate the applicability of more practical tests. Methodology A total of 70 peritoneal dialysis patients, 35 female (59%) and 24 male (41%), were included in the study. The mean age of the patients was 53 ± 14 years (range = 18-80 years), and the median peritoneal dialysis duration was 31.5 months (range = 20-56.2 months). The most common etiologic cause was hypertension (37%). Patients over 18 years of age who had been receiving peritoneal dialysis treatment for at least 24 months were included in the study. The correlation between patients' nPCR levels and serum asprosin, body mass index, and lipids was evaluated. Results The correlation between the level of nPCR and the serum asprosin level, body mass index, and lipids was evaluated. Patients with nPCR <0.815 were considered malnourished, and factors affecting malnutrition were determined by univariate analysis. Among the factors affecting malnutrition according to univariate analysis, those with p-value <0.05 were analyzed by multivariate analysis. Low asprosin level was one of the independent factors affecting malnutrition in patients (Exp(B) = 0.944, 95% confidence interval (CI) = 0.896-0.994). Other independent factors affecting malnutrition were Kt/V (Exp(B) = 0.018, 95% CI = 0.001-0.550) and residual renal function (Exp(B) = -0.004, 95% CI = 0.993-0.999). Conclusions There is a need for more accessible tests and reliable parameters to evaluate dialysis and nutritional deficiency in peritoneal dialysis patients. One possible hormone that could serve as a guide is asprosin.

Betatrophin, elabela, asprosin, glucagon and subfatin peptides in breast tissue, blood and milk in gestational diabetes

We investigated the presence of asprosin (ASP), betatrophin, elabela (ELA), glucagon and subfatin (SUB) in the milk of mothers with gestational diabetes mellitus (GDM) and compared their levels with blood levels. We also investigated whether these peptides are synthesized by the breast. We investigated 12 volunteer mothers with GDM and 14 pregnant non-GDM control mothers. The peptides were measured using ELISA and their tissue localization was determined using immunohistochemistry. Breast milk contains ASP, betatrophin, ELA, glucagon and SUB. The amount of the peptides ranged from highest to the lowest in colostrum, transitional milk and mature milk. The amount of peptides in the milk was greater than for blood. The peptides, except for ELA, were increased in milk and blood by GDM. Betatrophin and ELA are synthesized in the connective tissue of the breast. ASP, glucagon and SUB are synthesized in the alveolar tissue of the breast. These peptides in breast milk may contribute to the development of the gastrointestinal tract of newborns and infants.

Circulating Asprosin Concentrations in Patients with Obesity and Carbohydrate Disturbances

Asprosin is a fasting-induced glucogenic hormone, secreted by white adipose tissue in response to starvation. The aim of the current study was to determine the levels of asprosin in subjects from the entire spectrum of the carbohydrate metabolism. A total of 153 Causcasian subjects participated in this study: group 1, healthy volunteers; group 2, obese subjects without glycemic disturbances; group 3, subjects with prediabetes and group 4, patients with newly identified type 2 diabetes. Subject with body mass index≥30 kg/m2 and dysglycemia (prediabetes and diabetes) showed significantly high levels of asprosin (1.40 ng/ml [IQR=0.98-1.94]; 1.27 ng/ml [IQR=0.86-2.12]; 1.09 ng/ml [IQR=0.89-1.58]) compared to the control group (0.71 ng/ml [IQR=0.54-0.92]; p<0.001). Correlation analysis showed that serum asprosin also had significant positive associations with some anthropometric parameters, liver enzymes, fasting and post load glucose and insulin, LDL and triglycerides. Furthermore, we estimated a marked relationship between asprosin concentrations and intima media thickness of the common carotid artery as well as neuropathy disability and vibration sensitivity. The circulating asprosin levels for differentiating subjects with carbohydrate disturbances and those with obesity were determined by ROC analysis. The AUC for disturbances of the glucose metabolism was 0.672 (p<0.001; 95% CI=0.581-0.751) and for obesity AUC was 0.849 (p<0.001; 95% CI=0.785-0.919). Circulating asprosin could be used as a predictive factor for early carbohydrate disorders and might be a potential new therapeutic target for the treatment of dysglycemia and obesity. Further prospective studies are needed to confirm this observation.

Molecular cloning, characterization and 3D modelling of spotted snakehead fbn1 C-terminal region encoding asprosin and expression analysis of fbn1

The FBN1 gene encodes profibrillin protein that is cleaved by the enzyme furin to release fibrillin-1 and a glucogenic hormone, asprosin. Asprosin is implicated in diverse metabolic functions as well as pathological conditions in mammals. However, till date, there are no studies on asprosin in any non-mammalian vertebrate. In this study, we have retrieved the spotted snakehead Channa punctata fbn1 gene (ss fbn1) from the testicular transcriptome data and validated it. The transcript is predicted to encode 2817 amino acid long putative profibrillin protein. Amino acid sequence alignment of deduced ss profibrillin with human profibrillin revealed that the furin cleavage site in profibrillin is well conserved in C. punctata. Further, differential expression of ss fbn1 was observed in various tissues with the highest expression in gonads. Prominent expression of furin was also observed in the gonads suggesting the possibility of proteolytic cleavage of profibrillin protein and secretion of asprosin in C. punctata. In addition, the C-terminal of the fbn1 gene of C. punctata that codes for asprosin protein has been cloned. Using in silico approach, physicochemical properties of the putative ss asprosin were characterized and post-translational changes were predicted. The putative ss asprosin protein sequence is predicted to consist of 142 amino acid residues, with conserved glycosylation sites. Further, the 3D model of ss asprosin was predicted followed by MD (molecular dynamics) simulation for energy minimization. Thus, the current study, for the first time in non-mammalian vertebrates, predicts and characterizes the novel protein asprosin using in silico approach.

Asprosin Enhances Cytokine Production by a Co-Culture of Fully Differentiated Mature Adipocytes and Macrophages Leading to the Exacerbation of the Condition Typical of Obesity-Related Inflammation

Asprosin, a fasting-induced, glucogenic, and orexigenic adipokine, has gained popularity in recent years as a potential target in the fight against obesity and its complications. However, the contribution of asprosin to the development of moderate obesity-related inflammation remains still unknown. The present study aimed to evaluate the effect of asprosin on the inflammatory activation of adipocyte–macrophage co-cultures at various stages of differentiation. The study was performed on co-cultures of the murine 3T3L1 adipocyte and the RAW264.7 macrophage cell lines treated with asprosin before, during, and after 3T3L1 cell differentiation, with or without lipopolysaccharide (LPS) stimulation. Cell viability, overall cell activity, and the expression and release of key inflammatory cytokines were analyzed. In the concentration range of 50–100 nM, asprosin increased the pro-inflammatory activity in the mature co-culture and enhanced the expression and release of tumor necrosis factor α (TNF-α), high-mobility group box protein 1 (HMGB1), and interleukin 6 (IL-6). Macrophage migration was also increased, which could be related to the upregulated expression and release of monocyte chemoattractant protein-1 (MCP-1) by the adipocytes. In summary, asprosin exerted a pro-inflammatory effect on the mature adipocyte–macrophage co-culture and may contribute to the spread of moderate obesity-associated inflammation. Nevertheless, further research is needed to fully elucidate this process.

Correlation of asprosin and Nrg-4 with type 2 diabetes Mellitus Complicated with Coronary Heart Disease and the Diagnostic Value

PURPOSE

Asprosin is a newly discovered adipose factor secreted by white fat, which is involved in glucose metabolism and inflammation. Neuregulin-4 (Nrg-4) is a new adipose factor released from brown adipose tissue and is considered to play an important role in metabolism. This study aims to explore the association between serum Asprosin, Nrg-4 level and coronary heart disease(CHD) in patients with type 2 diabetes mellitus(T2DM) and the diagnostic value.

PATIENTS AND METHODS

157 patients with T2DM were enrolled from Affiliated Hospital of Chengde Medical University between December 2020 to July 2021. These patients were divided into T2DM without CHD group (T2DM-0, n = 80) and T2DM with CHD (T2DM-CHD, n = 77). Serum Asprosin and Nrg-4 expression was detected by enzyme-linked immunosorbent assay, and the correlations between Asprosin or Nrg-4 and clinical and biochemical indicators were analyzed. A receiver operating characteristics curve analysis and area under the curve (AUC) were used to evaluate diagnostic accuracy.

RESULTS

Serum Asprosin level of the T2DM-CHD group were significantly higher and Nrg-4 level significantly lower than those of the T2DM-0 group.Spearman correlation analysis showed that serum Asprosin levels were significantly positively correlated with diabetes course,history of hypertension, fasting plasma glucose(FPG), glycosylated hemoglobin A1c(HbA1C), triglycerides(TG),triglyceride glucose index(TyG index) and urea, and negatively correlated with ALT (all p < 0.05). Nrg-4 was negatively correlated with history of hypertension, body mass index(BMI), FPG, HbA1C, TG, and TyG indexes (all p < 0.05), and positively correlated with high-density lipoprotein cholesterol(HDL-C)(p < 0.05).Logistic regression analysis showed that after adjusting potential confounders, Asprosin was a risk factor for diabetes mellitus, Nrg-4 was a protective factor.The AUC of Asprosin for diagnosing T2DM-CHD was 0.671 (95% confidence interval [CI] 0.584-0.759), and the AUC of the Nrg4 index for diagnosing T2DM-CHD was 0.772 (95% CI 0.700-0.844). The AUC of Asprosin and Nrg-4 for the combined diagnosis of T2DM-CHD was 0.796 (95% CI 0.726-0.864).

CONCLUSION

Asprosin and Nrg-4 may be novel diagnostic biomarkers for T2DM with CHD, as they effectively improved the diagnostic accuracy for T2DM-CHD.

Asprosin aggravates vascular endothelial dysfunction via disturbing mitochondrial dynamics in obesity models

OBJECTIVE

The aim of the study was to investigate the contribution of asprosin (ASP), a fasting-induced hormone involved in metabolic disorders, to vascular endothelial dysfunction in obesity models.

METHODS

Primary rat thoracic aortic endothelial cells treated with palmitic acid and mice fed with a high-fat diet (HFD) were used as the obesity models. The role and mechanism of ASP in endothelial dysfunction were investigated by the means of morphologic, functional, and genetic analysis.

RESULTS

ASP aggravated the endothelial dysfunction induced by either palmitic acid in vitro or an HFD in vivo, characterized as the impairment of endothelium-dependent vasodilation, reduction of nitric oxide levels, elevation of malondialdehyde levels, and inhibition of phosphoinositide 3-kinase-AKT-endothelial nitric oxide synthase signaling. However, adipose conditional knockout of ASP or ASP neutralization significantly alleviated the endothelial dysfunction induced by an HFD. Mechanistically, ASP enhanced mitochondrial fission, and inhibition of the fission through knockdown of dynamin-related protein 1 (a fission-hallmark factor) rescued the endothelial dysfunction and the disturbance to mitochondrial dynamics induced by ASP.

CONCLUSIONS

The findings demonstrate that ASP causes and even exacerbates vascular endothelial dysfunction through promoting mitochondrial fission in obesity, suggesting that ASP can act as an early predictive marker of blood vessel dysfunction and become a novel potential therapeutic target for obesity-related cardiovascular diseases.

Asprosin promotes feeding through SK channel-dependent activation of AgRP neurons

Asprosin, a recently identified adipokine, activates agouti-related peptide (AgRP) neurons in the arcuate nucleus of the hypothalamus (ARH) via binding to protein tyrosine phosphatase receptor δ (Ptprd) to increase food intake. However, the intracellular mechanisms responsible for asprosin/Ptprd-mediated activation of AgRPARH neurons remain unknown. Here, we demonstrate that the small-conductance calcium-activated potassium (SK) channel is required for the stimulatory effects of asprosin/Ptprd on AgRPARH neurons. Specifically, we found that deficiency or elevation of circulating asprosin increased or decreased the SK current in AgRPARH neurons, respectively. AgRPARH-specific deletion of SK3 (an SK channel subtype highly expressed in AgRPARH neurons) blocked asprosin-induced AgRPARH activation and overeating. Furthermore, pharmacological blockade, genetic knockdown, or knockout of Ptprd abolished asprosin's effects on the SK current and AgRPARH neuronal activity. Therefore, our results demonstrated an essential asprosin-Ptprd-SK3 mechanism in asprosin-induced AgRPARH activation and hyperphagia, which is a potential therapeutic target for the treatment of obesity.

Effect of D-β-hydroxybutyrate-(R)-1,3 butanediol on plasma levels of asprosin and leptin: results from a randomised controlled trial

Background: D-β-Hydroxybutyrate-(R)-1,3 butanediol - a non-racemic ketone monoester for ingestion - has emerged as an effective way to achieve acute nutritional ketosis. Whether white adipose tissue plays a role in effects of acute nutritional ketosis is largely unknown. Objective: To investigate the effects of acute nutritional ketosis on plasma levels of asprosin and leptin and if they are affected by abdominal fat phenotypes. Methods: The design was a randomised crossover trial. Participants received either the D-β-hydroxybutyrate-(R)-1,3 butanediol monoester (KEβHB) drink or placebo drink. Blood samples were collected at baseline, 30, 60, 90, 120, and 150 minutes. 3.0 Tesla magnetic resonance imaging was used to measure visceral and subcutaneous fat volumes (VFV and SFV, respectively), intra-hepatic fat deposition (IHFD), and intra-pancreatic fat deposition (IPFD). Results: A total of 18 adults were randomised, with no drop-outs. There were no significant differences in plasma levels of asprosin and leptin (p = 0.808 and p = 0.907, respectively) between the KEβHB and placebo drinks. There was no effect of time, treatment, or interaction between time and treatment on asprosin and leptin. After stratification by the VFV/SFV ratio, IHFD, and IPFD, there were no differences in asprosin and leptin between the KEβHB and placebo drinks. Conclusion: Plasma levels of asprosin and leptin were not significantly affected by acute nutritional ketosis. Abdominal fat phenotypes did not significantly affect circulating levels of the two hormones. White adipose tissue does not appear to play a role in altering hormone levels during acute nutritional ketosis. The clinical trial registry number is NCT03889210 (https://clinicaltrials.gov).

Asprosin in health and disease, a new glucose sensor with central and peripheral metabolic effects

Adipose tissue malfunction leads to altered adipokine secretion which might consequently contribute to an array of metabolic diseases spectrum including obesity, diabetes mellitus, and cardiovascular disorders. Asprosin is a novel diabetogenic adipokine classified as a caudamin hormone protein. This adipokine is released from white adipose tissue during fasting and elicits glucogenic and orexigenic effects. Although white adipose tissue is the dominant source for this multitask adipokine, other tissues also may produce asprosin such as salivary glands, pancreatic B-cells, and cartilage. Significantly, plasma asprosin levels link to glucose metabolism, lipid profile, insulin resistance (IR), and β-cell function. Indeed, asprosin exhibits a potent role in the metabolic process, induces hepatic glucose production, and influences appetite behavior. Clinical and preclinical research showed dysregulated levels of circulating asprosin in several metabolic diseases including obesity, type 2 diabetes mellitus (T2DM), polycystic ovarian syndrome (PCOS), non-alcoholic fatty liver (NAFLD), and several types of cancer. This review provides a comprehensive overview of the asprosin role in the etiology and pathophysiological manifestations of these conditions. Asprosin could be a promising candidate for both novel pharmacological treatment strategies and diagnostic tools, although developing a better understanding of its function and signaling pathways is still needed.

Fibrillin-1 and asprosin, novel players in metabolic syndrome

Fibrillin-1 is a major component of the extracellular microfibrils, where it interacts with other extracellular matrix proteins to provide elasticity to connective tissues, and regulates the bioavailability of TGFβ family members. A peptide consisting of the C-terminal 140 amino acids of fibrillin-1 has recently been identified as a glucogenic hormone, secreted from adipose tissue during fasting and targeting the liver to release glucose. This fragment, called asprosin, also signals in the hypothalamus to stimulate appetite. Asprosin levels are correlated with many of the pathologies indicative of metabolic syndrome, including insulin resistance and obesity. Previous studies and reviews have addressed the therapeutic potential of asprosin as a target in obesity, diabetes and related conditions without considering mechanisms underlying the relationship between generation of asprosin and expression of the much larger fibrillin-1 protein. Profibrillin-1 undergoes obligatory cleavage at the cell surface as part of its assembly into microfibrils, producing the asprosin peptide as well as mature fibrillin-1. Patterns of FBN1 mRNA expression are inconsistent with the necessity for regulated release of asprosin. The asprosin peptide may be protected from degradation in adipose tissue. We present evidence for an alternative possibility, that asprosin mRNA is generated independently from an internal promoter within the 3' end of the FBN1 gene, which would allow for regulation independent of fibrillin-synthesis and is more economical of cellular resources. The discovery of asprosin opened exciting possibilities for treatment of metabolic syndrome related conditions, but there is much to be understood before such therapies could be introduced into the clinic.

Effects of GLP-1 receptor agonists on asprosin levels in normal weight or overweight/obesity patients with type 2 diabetes mellitus

Asprosin is a newly identified adipokine with glucose-raising and appetite-enhancing effects which acts differently from the known hepatic glucose utilization pathway. This study investigated changes in serum asprosin levels in normal weight or overweight/obese liraglutide-treated patients with type 2 diabetes (T2DM). This study is a non-randomized, prospective observational study. The metabolic parameters and asprosin levels were compared between 90 people with T2DM and 66 people who had normal glucose tolerance (NGT). During the treatment phase, only T2DM patients were given liraglutide at doses of 0.6 mg/d for the first 2 weeks, 1.2 mg/d for the subsequent 4 weeks, and 1.8 mg/d for the following 16 weeks. T2DM patients were separated into a normal weight group and an overweight/obesity group to compare changes in asprosin and parameters pre- and post-treatment. The T2DM group had significantly higher fasting asprosin and 2h-postprandial asprosin levels than the NGT group (all P < .001). Fasting asprosin and postprandial asprosin positively correlated with BMI, 2hPG, HbA1c, TG, and HOMA-IR, and negatively correlated with HDL-C in both the T2DM and NGT groups. Asprosin levels decreased after liraglutide treatment in both normal and overweight/obesity T2DM groups (all P < .001), with significantly reduced body weight and BMI in overweight/obese T2DM patients (all P < .001). Fasting and postprandial serum asprosin concentrations are higher in T2DM patients compared to normal glucose controls. Fasting and postprandial asprosin positively correlated with BMI, 2hPG, HbA1c, TG, and HOMA-IR and negatively correlated with HDL-C in all participants. Liraglutide lowers asprosin levels in T2DM patients and can reduce weight and BMI in overweight or obese type 2 diabetics.

The Effects of Asprosin on Exercise-Intervention in Metabolic Diseases

Fibrillin is the major constituent of extracellular microfibrils, which are distributed throughout connective tissues. Asprosin is derived from the C-terminal region of the FBN1 gene, which encodes profibrillin that undergoes cleavage by furin protein. In response to fasting with low dietary glucose, asprosin is released as a secreted factor from white adipose tissue, and is transported to the liver for the mediation of glucose release into the blood circulation. Through binding to OLFR734, an olfactory G-protein-coupled receptor in liver cells, asprosin induces a glucogenic effect to regulate glucose homeostasis. Bioinformatics analyses revealed that the FBN1 gene is abundantly expressed in human skeletal muscle-derived mesoangioblasts, osteoblast-like cells, and mesenchymal stem cells, indicating that the musculoskeletal system might play a role in the regulation of asprosin expression. Interestingly, recent studies suggest that asprosin is regulated by exercise. This timely review discusses the role of asprosin in metabolism, its receptor signalling, as well as the exercise regulation of asprosin. Collectively, asprosin may have a vital regulatory effect on the improvement of metabolic disorders such as diabetes mellitus and obesity via exercise.

Male Marfan mice are predisposed to high fat diet induced obesity, diabetes, and fatty liver

Gene mutations in the extracellular matrix protein fibrillin-1 cause connective tissue disorders including Marfan syndrome (MFS) with clinical symptoms in the cardiovascular, skeletal, and ocular systems. MFS patients also exhibit alterations in adipose tissues, which in some individuals leads to lipodystrophy, whereas in others to obesity. We have recently demonstrated that fibrillin-1 regulates adipose tissue homeostasis. Here, we examined how fibrillin-1 abnormality affects metabolic adaptation to different diets. We used two MFS mouse models: Hypomorph Fbn1^mgR/mgR mice and Fbn1^C1041G/+ mice with a fibrillin-1 missense mutation. When Fbn1^mgR/mgR mice were fed with high fat diet (HFD) for 12 weeks, male mice were heavier than littermate controls (LC), whereas female mice gained less weight compared to LC. Female Fbn1^C1041G/+ mice on a HFD for 24 weeks were similarly protected from weight gain. Male Fbn1^C1041G/+ mice on HFD demonstrated higher insulin levels, insulin intolerance, circulating levels of cholesterol and high-density lipoproteins. Moreover, male HFD-fed Fbn1^C1041G/+ mice showed a higher liver weight and a fatty liver phenotype, which was reduced to LC levels after orchiectomy. Phosphorylation of protein kinase-like endoplasmic reticulum kinase (PERK) as well as the expression of sterol regulatory element-binding protein 1 (Srebp1) in livers of HFD-fed male Fbn1^C1041G/+ mice were elevated. In conclusion, the data demonstrate that male mice of both MFS models are susceptible to HFD-induced obesity and diabetes. Moreover, male Fbn1^C1041G/+ mice develop a fatty liver phenotype, likely mediated by a baseline increased endoplasmic reticulum stress. In contrast, female MFS mice were protected from the consequence of HFD.

The modulatory effects of irisin on asprosin, leptin, glucose levels and lipid profile in healthy and obese male and female rats

OBJECTIVES

The main aim of this study was to investigate the effects of irisin on asprosin, leptin, glucose levels and lipid profile in healthy and obese male and female rats.

METHODS

Irisin was subcutaneously administered with osmotic minipumps at the dose of 100 ng/kg/day for 28 days and then, the serum levels of asprosin, leptin, glucose and lipid profile were investigated.

RESULTS

Irisin infusion increased asprosin levels in male rats (p = .02) but not in female rats. Irisin inhibited obesity-induced high glucose, low-density lipoprotein (LDL), triglyceride (TG) and leptin levels in all groups; however, it did not lead to any change in asprosin levels in both obese female and male rats.

CONCLUSIONS

It was determined that irisin increased serum asprosin levels and decreased LDL, TG, glucose and leptin levels, and this could indicate a protective role of irisin against obesity development.

Association of cord blood asprosin concentration with atherogenic lipid profile and anthropometric indices

BACKGROUND

Elevated lipids in umbilical cord blood affect fetal programming, leading to a higher risk of developing cardiovascular disease in later life. However, the causes of changes in the lipid profile of umbilical cord blood are not clear yet. This study aimed for the first time to determine the association of asprosin concentration with TAG, TC, HDL-C, LDL-C concentrations and TAG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C/HDL-C ratio in umbilical cord blood as well as newborn anthropometric indices. This cross-sectional study was based on 450 mother- newborn pairs of a birth cohort study in Sabzevar, Iran. Multiple linear regression was used to estimate the association of lipid concentration and lipid ratios as well as birth weight (BW), birth length (BL), head circumference (HC) and chest circumference (CC) with asprosin in cord blood samples controlled for the relevant covariates.

RESULT

In fully adjusted models, each 1 ng/mL increase in asprosin was associated with 0.19 (95% CI 0.06, 0.31, P < 0.01), 0.19 (95% CI 0.10, 0.29, P < 0.01), 0.17 (95% CI 0.09, 0.25, P < 0.01), 0.17 (95% CI 0.09, 0.25, P < 0.01), 0.01 (95% CI 0.00, 0.013, P < 0.01), 0.01 (95% CI 0.01, 0.01, P < 0.01), 0.01 (95% CI 0.01, 0.01, P < 0.01) and 0.01 (95% CI 0.01, 0.01, P < 0.01) increase in TAG, TC, LDL-C, TAG/HDL-C, TC/HDL-C, LDL-C/HDL-C and non-HDL-C/HDL-C ratio respectively. Moreover, higher asprosin levels was positively associated with newborn BW, BL, HC and CC; however, these associations were not statistically significant.

CONCLUSION

Overall, our findings support the positive association between cord asprosin concentration and the development of atherogenic lipid profile in newborns. Further studies are needed to confirm the findings of this study in other populations.

Asprosin, a C-Terminal Cleavage Product of Fibrillin 1 Encoded by the FBN1 Gene, in Health and Disease

BACKGROUND

Asprosin is a novel fasting-induced, glucogenic, and orexigenic protein hormone that is discovered with the help of genetic studies in patients with neonatal progeroid syndrome. Asprosin is encoded by the penultimate 2 exons (65 and 66) of the fibrillin 1 (FBN1) gene. Profibrillin 1 is the unprocessed protein product of FBN1 and undergoes a proteolytic cleavage by furin enzyme to produce mature fibrillin 1 and asprosin. The main organ responsible for the asprosin production seems to be white adipose tissue.

SUMMARY

Asprosin promotes hepatic glucose release in the liver and appetite stimulation in the hypothalamus through activation of the cAMP signaling circuitry through interacting with its G protein-coupled receptor, called OR4M1. Increasing mass of evidence suggests that asprosin is involved in the development and progression of various clinical conditions including diabetes, obesity, cardiomyopathy, cancer, and polycystic ovarian syndrome. It regulates various cellular and physiological processes such as appetite stimulation, glucose release, insulin secretion, apoptotic cell death, and inflammatory response. In this review, we discuss the current literature on asprosin and try to shed light on the yet undiscovered functions of asprosin.

KEY MESSAGE

Asprosin is a key regulatory factor for preserving the homeostasis of energy metabolism.

A cross-sectional comparative study on the effects of body mass index and exercise/sedentary on serum asprosin in male college students

Adipocytes regulate the body’s metabolism by secreting adipokines to maintain energy homeostasis. Asprosin is a new type of adipokine, and its relationship with obesity remains controversial. There are a few reports on the effect of long-term exercise on serum asprosin level. This study aimed to investigate the effects of body mass index (BMI) and exercise/sedentary habit on serum asprosin in male college students as well as the relationship between serum asprosin and body composition and related metabolic indicators and provided a basis for further exploration of the biological function of asprosin. Ninety-six male college students were classified into the sedentary habit group (SD; 48) and the special training experience group (ET; 48). Both groups included three subgroups of normal BMI, overweight, and obesity, with 16 people in each subgroup. One-way analysis of variance, analysis of covariance, and Pearson correlation analysis were performed. The results showed that serum asprosin levels in the obesity subgroup were significantly higher than those in the normal and overweight subgroups. Excluding BMI interference, there were no significant differences in serum asprosin between the SD and ET groups; however, there were significant differences in body composition, tumor necrosis factor-α, interleukin-6, and interleukin-10. Asprosin was positively correlated with BMI, body fat percentage, visceral fat area, fasting insulin, insulin resistance homeostasis model, total cholesterol, low-density lipoprotein, tumor necrosis factor-α, interleukin-6, and leptin levels and was negatively correlated with relative lean body mass, relative skeletal muscle mass, high-density lipoprotein, and interleukin-10, and adiponectin levels. In conclusion, serum asprosin is closely related to body weight, body composition, glucose and lipid metabolism, inflammatory response, and fat hormones. Long-term exercise training cannot prevent BMI increase from increasing serum asprosin level. If the influence of BMI is excluded, long-term exercise training does not affect serum asprosin.

Sensitive asprosin detection in clinical samples reveals serum/saliva correlation and indicates cartilage as source for serum asprosin

The C-terminal pro-fibrillin-1 propeptide asprosin is described as white adipose tissue derived hormone that stimulates rapid hepatic glucose release and activates hunger-promoting hypothalamic neurons. Numerous studies proposed correlations of asprosin levels with clinical parameters. However, the enormous variability of reported serum and plasma asprosin levels illustrates the need for sensitive and reliable detection methods in clinical samples. Here we report on newly developed biochemical methods for asprosin concentration and detection in several body fluids including serum, plasma, saliva, breast milk, and urine. Since we found that glycosylation impacts human asprosin detection we analyzed its glycosylation profile. Employing a new sandwich ELISA revealed that serum and saliva asprosin correlate strongly, depend on biological sex, and feeding status. To investigate the contribution of connective tissue-derived asprosin to serum levels we screened two cohorts with described cartilage turnover. Serum asprosin correlated with COMP, a marker for cartilage degradation upon running exercise and after total hip replacement surgery. This together with our finding that asprosin is produced by primary human chondrocytes and expressed in human cartilage suggests a contribution of cartilage to serum asprosin. Furthermore, we determined asprosin levels in breast milk, and urine, for the first time, and propose saliva asprosin as an accessible clinical marker for future studies.

Association Between Serum Asprosin and Diabetic Nephropathy in Patients with Type 2 Diabetes Mellitus in the Community: A Cross-Sectional Study

OBJECTIVE

To explore the association between serum asprosin and diabetic nephropathy (DN) in patients with type 2 diabetes mellitus (T2DM) in the community.

METHODS

In this cross-sectional study, we retrospectively collected the clinical data of T2DM patients from a community health service center in southeastern Shanxi Province between November 2019 and July 2021. Logistic regression analysis was used to calculate the odds ratio (OR) and the 95% confidence interval (95% CI) of asprosin levels on the risk of DN.

RESULTS

Among 498 T2DM patients included in this study, 221 had microalbuminuria, 105 had massive albuminuria, and 172 did not have any signs of nephropathy. Serum asprosin level was positively correlated with diastolic blood pressure, body mass index, triglycerides, aspartate aminotransferase, alanine aminotransferase, creatinine, ACR and albumin-to-creatinine ratio (all P < 0.05) and negatively correlated with low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting plasma glucose, HbA1c and estimated glomerular filtration rate (all P < 0.05). After adjusting for covariates, increased asprosin was associated with diabetic nephropathy (all OR = 2.560, 95% CI: 1.1592-4.116; P < 0.001).

CONCLUSION

The risk of DN significantly increases with serum asprosin levels, especially among female patients.

New Discovered Adipokines Associated with the Pathogenesis of Obesity and Type 2 Diabetes

Obesity is defined as abnormal or excessive accumulation of adipose tissue, closely associated with the increased risk of various comorbidities, especially type 2 diabetes mellitus (T2DM). Adipose tissue is a complex structure responsible for not only fat storage but also releasing adipokines which may play roles in the pathogenesis and could be developed into biomarkers for diagnosis, treatment and prognosis of obesity-related metabolic diseases. This review aims to summarize several adipokines discovered recently that have promising functions in obesity and T2DM. Among them, the levels of FSTL1, WISP1 and Asprosin in subjects with obesity or diabetes are commonly higher than in normal controls, suggesting that they may be pathogenic. Inversely, SFRP5, Metrnl, NRG4 and FAM19A5 may serve as the protective factors.

Sex-Specific Effects of Maternal and Post-Weaning High-Fat Diet on Adipose Tissue Remodeling and Asprosin Expression in Mice Offspring

SCOPE

Perinatal high-fat diet (HFD) increases risk of metabolic disorders in offspring. Adipose tissue remodeling is associated with metabolic syndrome. The current study characterizes the profile of maternal HFD-induced changes in adipose tissue remodeling and adipokines expression in mice offspring.

METHODS AND RESULTS

Female C57BL/6 mice are fed with CHOW or HFD for 2 weeks before mating, throughout gestation and lactation. At weaning, pups are randomly fed with CHOW or HFD, resulting in eight groups according to sex and maternal diet: Male CHOW-CHOW (MCC), Male CHOW-HFD (MCH), Male HFD-CHOW (MHC), Male HFD-HFD (MHH), Female CHOW-CHOW (FCC), Female CHOW-HFD (FCH), Female HFD-CHOW (FHC), and Female HFD-HFD (FHH). Increased body weight, impaired glucose tolerance, increased adipose tissue mass and hypertrophy, and decreased circulating asprosin level are only observed in male offspring exposure to maternal HFD. Serum asprosin level negatively correlates with fasting blood glucose, serum cholesterol (CHO), and high-density lipoprotein (HDL) levels, while positively correlates with serum low-density lipoprotein (LDL) and glutamate-oxaloacetate transaminase (GOT) levels in male offspring. A combination of genetic and biochemical analyses of adipokines shows the depot- and sex-specific changes in response to maternal and/or post-weaning HFD.

CONCLUSION

This study's results reveal the differential metabolic changes in response to maternal and/or post-weaning HFD in male and female offspring. The effect of maternal HFD on metabolic phonotype is more obvious in male offspring, supporting the notion that males are more susceptible to HFD-induced metabolic disorders.

A Serum Marker for Early Pancreatic Cancer with a Possible Link to Diabetes

BACKGROUND

Pancreatic cancer (PC) has a grim prognosis, and an early diagnostic biomarker has been highly desired. The molecular link between diabetes and PC has not been well-established.

METHODS

Bioinformatics screening was performed for a serum PC marker. Experiments in cell lines (5 PC and 1 normal cell lines), mouse models, and human tissue staining (37 PC and 10 normal cases) were performed to test asprosin production from PC. Asprosin's diagnostic performance was tested with serums from multi-center cohorts (347 PC, 209 normal, and 55 additional diabetic subjects) and evaluated according to PC status, stages, and diabetic status, which was compared with that of CA19-9.

RESULTS

Asprosin, a diabetes-related hormone, was found from the bioinformatics screening, and its production from PC was confirmed. Serum asprosin levels from multi-center cohorts yielded an age-adjusted diagnostic AUC of 0.987 (95% confidence interval [CI] = 0.961 to 0.997), superior to that of CA19-9 (AUC = 0.876, 95% CI = 0.847 to 0.905), and a cut-off of 7.18 ng/mL, at which the validation set exhibited a sensitivity of 0.957 and a specificity of 0.924. Importantly, the performance was maintained in early-stage and non-metastatic PC, consistent with the tissue staining. A slightly lower performance against additional diabetic patients (n = 55) was restored by combining asprosin and CA19-9 (AUC = 0.985, 95% CI = 0.975 to 0.995).

CONCLUSION

Asprosin is presented as an early-stage PC serum marker that may provide clues for PC-induced diabetes. Larger prospective clinical studies are warranted to solidify its utility.

An investigation of the relationship between new fasting hormone asprosin, obesity and acute-chronic exercise: current systematic review

The purpose of this study was to reveal the relationship between new fasting hormone asprosin, obesity, and acute-chronic exercise. The prisma guidelines were followed in forming the methodological model of this review. The articles between 2016 and 2020 (including March) were identified by scanning Google Scholar, Pub Med, and Science Direct databases. Thirty-five articles were defined from 188 articles. Three cross-sectional, and 1 prospective cohort design studies in adults, and 3 cross-sectional studies in children were found. Three randomised-control group designed studies which examined the effect of acute exercise on serum asprosin levels in obese individuals. Asprosin may be a new therapeutic biomarker to be considered in the development, but long-term and deep-rooted researches are needed, and increasing the number of studies examining the effect of exercise on asprosin in the future might help us to identify the mechanisms underlying the decrease or increase in asprosin after exercise.

Increased asprosin is associated with non-alcoholic fatty liver disease in children with obesity

BACKGROUND

Obesity is a common disease among children, often accompanied by a lot of metabolic disease. Non-alcoholic fatty liver disease (NAFLD) is one of the most common complications of obesity among children and adolescents. Asprosin has been identified as a new adipokine that is closely associated with hepatic glucose metabolism. However, few data on asprosin in obese children with NAFLD are available. The present study focuses on the relationship between serum asprosin level and NAFLD in children with obesity.

METHODS

A total of 110 subjects (71 boys and 39 girls aged 6-18 years) were recruited from the Second Affiliated Hospital of Xi'an Jiaotong University: 36 obese children with NAFLD, 39 obese children without NAFLD and 35 lean controls. Anthropometric parameters and biochemical data were measured, and the concentrations of asprosin were detected by ELISA.

RESULTS

The levels of serum asprosin were significantly higher in obese children, particularly those with NAFLD and were positively correlated with body mass index, waist to height ratio, fasting blood glucose, alanine aminotransferase and tumor necrosis factor-alpha. Furthermore, asprosin was independently associated with NAFLD in binary logistic regression analysis.

CONCLUSION

Serum asprosin levels were elevated in obese children, especially in those with NAFLD, and were involved in the pathogenesis of NAFLD in children with obesity.

A pancancer overview of FBN1, asprosin and its cognate receptor OR4M1 with detailed expression profiling in ovarian cancer

Ovarian cancer affects >295,000 women worldwide and is the most lethal of gynaecological malignancies. Often diagnosed at a late stage, current research efforts seek to further the molecular understanding of its aetiopathogenesis and the development of novel biomarkers. The present study investigated the expression levels of the glucogenic hormone asprosin [encoded by fibrillin-1 (FBN1)], and its cognate receptor, olfactory receptor 4M1 (OR4M1), in ovarian cancer. A blend of in silico open access The Cancer Genome Atlas data, as well as in vitro reverse transcription-quantitative PCR (RT-qPCR), immunohistochemistry and immunofluorescence data were used. RT-qPCR revealed expression levels of OR4M1 and FBN1 in clinical samples and in ovarian cancer cell lines (SKOV-3, PEO1, PEO4 and MDAH-2774), as well as the normal human ovarian surface epithelial cell line (HOSEpiC). Immunohistochemical staining of a tissue microarray was used to identify the expression levels of OR4M1 and asprosin in ovarian cancer samples of varying histological subtype and grade, including clear cell carcinoma, serous ovarian cancer and mucinous adenocarcinoma. Immunofluorescence analysis revealed asprosin expression in SKOV-3 and HOSEpiC cells. These results demonstrated the expression of both asprosin and OR4M1 in normal and malignant human ovarian tissues. This research invokes further investigation to advance the understanding of the role of asprosin and OR4M1 within the ovarian tumour microenvironment.

Asprosin, a novel pleiotropic adipokine implicated in fasting and obesity-related cardio-metabolic disease: Comprehensive review of preclinical and clinical evidence

White adipose tissue is a dynamic endocrine organ that releases an array of adipokines, which play a key role in regulating metabolic homeostasis and multiple other physiological processes. An altered adipokine secretion profile from adipose tissue depots frequently characterizes obesity and related cardio-metabolic diseases. Asprosin is a recently discovered adipokine that is released in response to fasting. Following secretion, asprosin acts - via an olfactory G-protein coupled receptor and potentially via other unknown receptor(s) - on hepatocytes and agouti-related peptide-expressing neurons in the central nervous system to stimulate glucose secretion and promote appetite, respectively. A growing body of both in vitro and in vivo studies have shown asprosin to exert a number of effects on different metabolic tissues. Indeed, asprosin can attenuate insulin signalling and promote insulin resistance in skeletal muscle by increasing inflammation and endoplasmic reticulum stress. Interestingly, asprosin may also play a protective role in cardiomyocytes that are exposed to hypoxic conditions. Moreover, clinical studies have reported elevated circulating asprosin levels in obesity, type 2 diabetes and other obesity-related cardio-metabolic diseases, with significant associations to clinically relevant parameters. Understanding the spectrum of the effects of this novel adipokine is essential in order to determine its physiologic role and its significance as a potential therapeutic target and/or a biomarker of cardio-metabolic disease. The present review offers a comprehensive overview of the published literature on asprosin, including both clinical and preclinical studies, focusing on its role in metabolism and cardio-metabolic disease.

Increased serum asprosin is correlated with diabetic nephropathy

OBJECTIVE

The adipokine asprosin, which was recently discovered, facilitates hepatic glucose production. The aim of this study is to see whether serum asprosin concentrations are linked to diabetic nephropathy (DN).

METHODS

We performed this investigation in a group of 212 type 2 diabetes (T2DM) patients. These patients were classified into three subgroups: DN0 group (normal to mildly increased), DN1 group (moderately increased), and DN2 group (severely increased) on the basis of urine albumin-to-creatinine ratio (ACR).

RESULTS

When compared to the controls, T2DM patients had higher serum asprosin levels. The DN2 group had significantly higher serum asprosin than the DN0 and DN1 groups. Furthermore, the DN1 group had higher serum asprosin than the DN0 group. Serum asprosin was linked to a higher risk of T2DM and DN in a logistic regression analysis. Serum asprosin was found to be positively related with disease duration, systolic blood pressure, blood urea nitrogen, creatinine, uric acid, ACR, calcium channel blockers, and angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker therapy, but negatively related with glomerular filtration rate, metformin, and acarbose therapy.

CONCLUSION

Serum asprosin increase with the progression of DN. Serum asprosin is correlated with renal function and ACR.

Effect of sodium-glucose co-transporter-2 inhibitors on the levels of serum asprosin in patients with newly diagnosed type 2 diabetes mellitus

BACKGROUND

Asprosin, a novel adipokine that raises glucose levels and stimulates appetite, has been proved to be pathologically increased in populations predisposed to type 2 diabetes mellitus (T2DM), obesity, and cardiovascular diseases. The mechanisms of sodium-glucose co-transporter-2 (SGLT2) inhibitors for hypoglycemic effect and cardiovascular protection have not been fully clarified. Therefore, we conducted this study to assess change in the levels of serum asprosin after treatment with SGLT2 inhibitors in patients with newly diagnosed T2DM.

METHODS

This study was a randomized, double-blind, placebo-controlled trial. A total of 29 participants with newly diagnosed T2DM with body mass index (BMI) ≥ 23.0 kg/m² and haemoglobin A1c (HbA1c) levels of 58-85 mmol/mol (7.5-10%) were randomized to SGLT2 inhibitors dapagliflozin 10 mg/d (n = 19) or placebo (n = 10) treatment for 24 weeks. We analyzed asprosin concentrations by an enzyme-linked immunosorbent assay. Besides, body weight, BMI, HbA1c, fasting plasma glucose (FPG), and lipid levels were measured at baseline and 24 weeks.

RESULTS

At 24 weeks, participants with SGLT2 inhibitors treatment exhibited lower levels of serum asprosin (22.87 vs 45.06 ng/ml in the placebo group; P < 0.001) after adjusting for baseline values. The levels of body weight, BMI, HbA1c, FPG, and triglyceride (TG) were decreased, while high density lipoprotein-cholesterol (HDL-C) was increased after SGLT2 inhibitors dapagliflozin treatment compared with placebo (P < 0.05 for all). Low density lipoprotein-cholesterol (LDL-C) and total cholesterol (TC) levels were unchanged in the SGLT2 inhibitors group and placebo group. No statistical correlation was found between the levels of serum asprosin and body weight, BMI, HbA1c, FPG, and lipid levels during the SGLT2 inhibitor dapagliflozin treatment.

CONCLUSIONS

These findings indicated that SGLT2 inhibitors can lower serum asprosin levels and improve glucolipid and weight in patients with newly diagnosed T2DM, which may benefit the cardiovascular system. Trial registration CTR20131268; Registered 20 March 2014 CTR20150102; Registered 03 March 2015. http://www.chinadrugtrials.org.cn/clinicaltrials.searchlistdetail.dhtml .

Asprosin serum levels and glucose homeostasis in children with obesity

PURPOSE

Asprosin is a novel adipokine involved in glucose homeostasis, food intake regulation and energy homeostasis. However, the role of asprosin in glucose homeostasis regulation remains still controversial, especially in pediatrics. Aims of the study were to compare fasting serum asprosin levels between obese children and controls and to investigate the relationships of asprosin with body mass index (BMI) and biochemical markers of insulin resistance, insulin sensitivity, β-cell function and cardio-metabolic risk in obese non-diabetic children.

METHODS

This cross-sectional, case-controlled, study included 43 obese children and 24 lean matched controls consecutively recruited. Children underwent clinical and biochemical assessments, including oral glucose tolerance test. Fasting asprosin serum levels were measured using an enzyme-linked immunosorbentassay (ELISA). Homeostasis model assessment of insulin resistance (HOMA-IR), homeostasis model assessment of β-cell function (HOMA-B), Matsuda-index, Insulinogenic-index, Areas Under the Curves for glucose and insulin were calculated. Successively, asprosin variable was dichotomized according to mean value in order to create two ordered classes of values.

RESULTS

Fasting asprosin concentration was significantly lower in obese children compared to controls (331.9 ± 120.5 vs 358.1 ± 74.1 pg/ml; p = 0.013). Asprosin was lower in boys than in girls (313.7 ± 59.5 vs 361.1 ± 127.2 pg/ml; p = 0.044), while BMI standard deviation score (SDS) was higher in boys compared to girls (p = 0.024). Asprosin was negatively correlated with BMI (p = 0.024), BMI SDS (p = 0.044) and male sex (p = 0.043) in the entire cohort. No significant differences in asprosin levels were demonstrated between insulin resistant and non-insulin resistant obese children. Logistic regression models documented a significant negative association between BMI SDS and dichotomized asprosin. In particular, higher BMI SDS values were associated to lower asprosin serum levels class. A receiver operating characteristic (ROC) analysis showed existence of the best cut-off for BMI SDS (+2.7 SDS) variable into discriminating patients belonging to two asprosin classes in our cohort.

CONCLUSIONS

In conclusion, asprosin serum levels were significantly lower in obese children compared to control. Fasting asprosin decreased with increasing BMI, but it was not significantly affected by IR.

Asprosin-A Fasting-Induced, Glucogenic, and Orexigenic Adipokine as a New Promising Player. Will It Be a New Factor in the Treatment of Obesity, Diabetes, or Infertility? A Review of the Literature

Asprosin is a recently discovered protein released during fasting conditions mainly by adipocytes from white adipose tissue. As a glucogenic peptide, it stimulates the release of glucose from hepatic cells by binding to the OLFR734 receptor and leading to the activation of the G protein-cAMP-PKA pathway. As it crosses the blood–brain barrier, it also acts as an orexigenic peptide that stimulates food intake through activation of AgRP neurons in the hypothalamus; thus, asprosin participates in maintaining the body’s energy homeostasis. Moreover, studies have shown that asprosin levels are pathologically elevated in obesity and related diseases. However, the administration of anti-asprosin antibodies can both normalize its concentration and reduce food intake in obese mice, which makes it an interesting factor to combat obesity and related diseases. Current research also draws attention to the relationship between asprosin and fertility, especially in men. Asprosin improves age- and obesity-related decrease in fertility potential by improving sperm motility. It should also be mentioned that plasma asprosin levels can be differentially modulated by physical activity; intense anaerobic exercise increases asprosin level, while aerobic exercise decreases it. However, further research is necessary to confirm the exact mechanisms of asprosin activity and its potential as a therapeutic target.

High Serum Asprosin Levels Are Associated with Presence of Metabolic Syndrome

OBJECTIVE

Asprosin, a new adipocytokine, has reportedly been associated with glucose release, dyslipidemia, and insulin resistance (IR). However, the relationship of asprosin with metabolic syndrome (MetS) remains unknown. This study aimed to investigate serum asprosin levels in MetS as well as their association with various metabolic parameters in humans.

METHODS

A total of 131 consecutive patients with MetS, and 162 age-matched, healthy subjects were recruited for this study. Serum asprosin concentrations were determined using the enzyme-linked immunosorbent assay. Lipid profile, glucose, insulin, and inflammatory markers were also measured.

RESULTS

Serum asprosin levels were higher in subjects with MetS (23.52 [16.70, 32.05] ng/mL) than in controls (16.70 [12.87, 22.38] ng/mL; P < 0.01), and they showed an increasing trend with increasing numbers of metabolic components (P for trend < 0.01). In all studied subjects, serum asprosin levels were positively correlated with body mass index, waist circumference, triglycerides, fasting plasma glucose, 2-hour plasma glucose, fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR) index, interleukin-6, and monocyte chemoattractant protein-1 and negatively correlated with high-density lipoprotein cholesterol (P < 0.05). In multiple linear regression, asprosin was independently and positively correlated with triglyceride and HOMA-IR (P < 0.05). Binary logistic regression revealed that asprosin was independently and positively correlated with the occurrence of MetS and IR, even after controlling for anthropometric variables, lipid profiles, and inflammatory markers.

CONCLUSION

Asprosin is a potential metabolic-related adipokine and may be related to IR and MetS. This trial was registered with ChiCTR, ChiCTR1800018347.

Meal-Related Asprosin Serum Levels Are Affected by Insulin Resistance and Impaired Fasting Glucose in Children With Obesity

Asprosin physiologically increases in fasting conditions and decreases with refeeding and has been implicated in glucose homeostasis. An alteration of meal-related circadian oscillation of asprosin has been suggested in adults affected by type 2 diabetes mellitus. Aims of this study were to test the hypothesis of an alteration in the meal-related variation of asprosin levels in non-diabetic children and adolescents with obesity and to assess which metabolic variables condition this variation in non-diabetic children and adolescents with obesity. This is a cross-sectional study which included 79 children and adolescents with obesity. Children underwent clinical and biochemical assessments, including oral glucose tolerance test (OGTT), and liver ultrasound evaluation. Asprosin serum levels were measured by an enzyme-linked immunosorbent assay at a fasting state and at the 120-minute OGTT timepoint (2h-postprandial asprosin). Fasting and 2h-postprandial asprosin serum levels did not significantly differ in the entire study population (374.28 ± 77.23 vs 375.27 ± 81.26;p=0.837). 55.7% of patients had a significant increase in 2h-postprandial asprosin compared with fasting levels. The asprosin level increase condition was significantly associated with HOMA-IR (OR,1.41; 95%CI,1.005-1.977; p=0.047), fasting glycaemia (OR,1.073; 95%CI,1.009-1.141;p=0.024) and HOMA-B (OR,0.99; 95%CI,0.984-0.999; p=0.035). Moreover, the IFG condition was associated with the increase in asprosin levels (OR, 3.040; 95%CI, 1.095-8.436; p=0.033), even after adjustment for HOMA-IR, BMI SDS, sex and pubertal stage. Insulin resistance and IFG influence meal-related changes of asprosin serum levels in our study population of obese, non-diabetic, children. Alteration of asprosin circadian secretion might be an early biomarker of impaired glucose regulation in obese children with insulin resistance.

A state of the art review on the novel mediator asprosin in the metabolic syndrome

Metabolic syndrome is a complex and heterogeneous pathology characterized by a cluster of biochemical, clinical, and metabolic factors that came together in raising the risk of cardiovascular diseases, type 2 diabetes mellitus, and all-cause mortality. Some of these features are well defined in this syndrome like: obesity, inflammation, hypertension, insulin resistance, atherosclerotic dyslipidemias, endothelial dysfunction, and inflammation. This circuit is intermediated by a complex network of hormones, cytokines, transcription factors, and adipokines, among others. Some like leptin, adiponectin, Plasminogen activator inhibitor-1, interleukin-6, Tumor necrosis factor, and their influence on the metabolic syndrome are well described in the literature and new players are described continuously. One novel player was described in 2016 by Romere et al as a fasting-induced glycogenic protein hormone named asprosin. In order to perform a state-of-the-art, nonsystematic review of asprosin, a study of the available literature was carried out in the main database (Pubmed) and the results were studied and correlated to better understand the mechanism of action of this hormone. Asprosin is not only associated with the metabolic syndrome features like glucose and lipid metabolism, insulin resistance, obesity and inflammation but also in other pathologies metabolic syndrome related like diabetic retinopathy, polycystic ovary syndrome and anorexia nervosa. A limited number of pathways were already unveiled although much more research is needed to better understand the therapeutical potential of asprosin in the metabolic syndrome.

Novel Targets in Glucose Homeostasis and Obesity-Lesson from Rare Mutations

PURPOSE OF REVIEW

Obesity and diabetes have already become the second largest risk factor for cardiovascular disease. During the last decade, remarkable advances have been made in understanding the human genome's contribution to glucose homeostasis disorders and obesity. A few studies on rare mutations of candidate genes provide potential genetic targets for the treatment of diabetes and obesity. In this review, we discussed the detailed findings of these studies and the possible causalities between specific genetic variations and dysfunctions in energy or glucose homeostasis. We are optimistic that novel therapeutic strategies targeting these specific mutants for treating and preventing diabetes and obesity will be developed in the near future.

RECENT FINDINGS

Studies on rare genetic mutation-caused obesity or diabetes have identified potential genetic targets to decrease body weight or reduce the risk of diabetes. Rare mutations observed in lipodystrophy, obese, or diabetic human patients are promising targets in the treatment of diabetes and obesity.

Asprosin is associated with anorexia and body fat mass in cancer patients

PURPOSE

Increasing evidence suggests that many adipokines are involved in cancer-related anorexia and cachexia syndrome (CACS), although the underlying mechanism remains to be clarify. Asprosin is a new peptide hormone mainly secreted by white adipose tissues that can increase appetite and body weight. In this cross-sectional study, we tested whether asprosin may intervene in the development of CACS.

METHODS

The fasting plasma asprosin levels were determined via enzyme-linked immune-sorbent assay. Anorexia was determined using the anorexia/cachexia subscale (A/CS) of the functional assessment of anorexia/cachexia therapy (FAACT) questionnaire. The body composition was assessed using bioelectrical impedance analysis. The association of plasma asprosin with anorexia, cachexia, and nutritional status was analyzed.

RESULTS

One hundred twenty treatment-naïve patients with pathological confirmed gastrointestinal or lung cancer and 14 mild gastritis patients were recruited. We found no significant difference in asprosin levels between subgroups of patients by age, sex, cancer types or stage. Correlation analysis suggested that asprosin levels were positively associated with body fat mass (r = 0.248, p = 0.043). No correlations were found between asprosin levels and hemoglobin, white blood cell count, blood platelet count, albumin, C-reactive protein, glucose, cholesterol, triglyceride, high density lipoprotein, low density lipoprotein, body mass index, body fat percentage, protein, skeletal muscle, muscle mass, lean body mass, and basal metabolic rate. Furthermore, asprosin levels were not significantly different between patients with or without cachexia. However, patients with anorexia had significantly lower asprosin levels compared with patients without anorexia. No significant difference in asprosin levels between gastritis and gastric cancer patients. Similarly, no significant change of asprosin levels occurred postoperatively in 10 gastric cancer patients.

CONCLUSIONS

Patients with anorexia had significantly lower asprosin levels compared with patients without anorexia. We therefore speculated that asprosin might intervene in the development of cancer anorexia and serve as a potential therapeutic target.

Circulating asprosin levels are increased in patients with type 2 diabetes and associated with early-stage diabetic kidney disease

PURPOSE

Asprosin was a newly identified secreted hormone which could induce hepatic glucose release. Since asprosin closely associated with the risk factors of diabetic kidney disease (DKD), including hyperglycemia, insulin resistance and inflammation, the present study aimed to investigate the relationship between circulating asprosin levels and the early stage of DKD.

METHODS

30 subjects with normal glucose tolerance (NGT), 42 type 2 diabetes (T2DM) patients without DKD and 33 T2DM patients with early stage of DKD were recruited. Early stage of DKD was defined as two consecutive measurements of urinary albumin-to-creatinine ratio (UACR) 30-299 mg/g and estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73m². Multiple linear regression analysis was conducted to explore the associations of circulating asprosin levels with eGFR and UACR. Multiple logistic regression analysis was used to determine the association of circulating asprosin levels with the early stage of DKD.

RESULTS

Circulating asprosin levels in Non-DKD and DKD groups were significantly higher than that in NGT group and the DKD group showed the highest levels. Circulating asprosin levels negatively correlated with eGFR (r = - 0.311, P = 0.007) and positively correlated with UACR (r = 0.345, P = 0.002) in T2DM patients. Even after multivariable adjustment, circulating asprosin levels were closely associated with eGFR and UACR and significantly increased ORs for early stage of DKD (OR = 3.973, P = 0.001).

CONCLUSION

Circulating asprosin levels were increased in T2DM and associated with the early stage of DKD. The specific role of asprosin in DKD needs further investigation.

Fibrillin-1 and fibrillin-1-derived asprosin in adipose tissue function and metabolic disorders

The extracellular matrix microenvironment of adipose tissue is of critical importance for the differentiation, remodeling and function of adipocytes. Fibrillin-1 is one of the main components of microfibrils and a key player in this process. Furin processing of profibrillin-1 results in mature fibrillin-1 and releases the C-terminal propeptide as a circulating hunger hormone, asprosin. Mutations in the fibrillin-1 gene lead to adipose tissue dysfunction and causes Marfan syndrome, marfanoid progeroid lipodystrophy syndrome, and neonatal progeroid syndrome. Increased TGF-β signaling, altered mechanical properties and impaired adipogenesis are potential causes of adipose tissue dysfunction, mediated through deficient microfibrils. Circulating asprosin on the other hand is secreted primarily by white adipose tissue under fasting conditions and in obesity. It increases hepatic glucose production and drives insulin secretion and appetite stimulation through inter-organ cross talk. This review discusses the metabolic consequences of fibrillin-1 and fibrillin-1-derived asprosin in pathological conditions. Understanding the dynamic role of fibrillin-1 in the adipose tissue milieu and of circulating asprosin in the body can provide novel mechanistic insights into how fibrillin-1 may contribute to metabolic syndrome. This could lead to new management regimens of patients with metabolic disease.

Serum concentration of asprosin in new-onset type 2 diabetes

BACKGROUND

Asprosin, a newly identified adipokine, is pathologically increased in individuals with insulin resistance. However, the available evidence on the association of asprosin and type 2 diabetes mellitus (T2DM) status is still scarce. Therefore, this study aimed to determine the relationship between serum concentrations of asprosin and T2DM status.

METHODS

This observational study was performed based on 194 adults (97 newly diagnosed T2DM and 97 healthy individuals). Anthropometric and biochemical variables were determined in all participants. Serum concentrations of asprosin were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

In patients with T2DM, the serum concentrations of asprosin were significantly higher than the healthy controls (4.18 [IQR: 4.4] vs. 3.5 [IQR: 1.85], P < 0.001). The concentrations of asprosin were significantly correlated with body mass index (BMI) and fasting blood glucose (FBG) in healthy subjects and with BMI, FBG, hemoglobin A1c (HbA1c), homeostatic model assessment of insulin resistance (HOMA-IR), and quantitative insulin check index (QUICKI), triacylglycerol (TAG) and total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) ratio in the T2DM group. In fully adjusted model, the odds ratio (OR) of T2DM with serum concentrations of asprosin was approximately 1.547 (95% CI 1.293-1.850, P < 0.001) compared to the control group. Multiple stepwise regression analysis indicated that FBG and HOMA-IR were independently associated with asprosin in T2DM.

CONCLUSION

Our findings indicated that serum concentrations of asprosin are increased in patients with T2DM. Also, asprosin is correlated with insulin resistance and TC/HDL-C ratio (atherosclerotic risk factor of cardiovascular diseases) in patients with T2DM.