Increased activin A levels in prediabetes and association with carotid intima-media thickness: a cross-sectional analysis from I-Lan Longitudinal Aging Study

Activin A as a potential biomarker for preserved ratio impaired spirometry (PRISm) and clinical outcomes in community-dwelling adults

INTRODUCTION

This study endeavors to decipher the association between Activin A and PRISm, thereby addressing the potential of Activin A as a serum biomarker for early detection and long-term clinical outcome prediction of PRISm and subsequent all-cause mortality.

METHODS

The study sample comprised middle-aged and older adults from the I-Lan Longitudinal Aging Study. Pulmonary function including forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were measured. Demographic data and laboratory data (including serum Activin A levels) were also collected. Multivariate logistic regression and Cox proportional hazards models were used to identify independent predictors of PRISm and all-cause mortality, respectively.

RESULTS

Among 711 eligible participants, 34 % had PRISm. The risk of PRISm elevated with Activin A levels in group quartiles (adjusted odds ratio (aOR), Q2: 1.606 [95 % CI 0.972-2.652], p = 0.064, Q3: 2.666 [1.635-4.348], p < 0.001, Q4: 3.225 [1.965-5.293], p < 0.001). On the other hand, lower hemoglobin (aOR: 1.122, p = 0.041) and higher blood urea nitrogen (BUN) levels (aOR: 1.033, p = 0.048) were associated with increased risk of PRISm. In addition, the PRISm group had a higher all-cause mortality rate (non-PRISm 4.5% vs. PRISm 8.3 %, p = 0.038). Multivariate Cox models also identify a higher level of Activin A as a risk factor of all-cause mortality (aHR: 1.001 [1.000-1.003], p = 0.042).

CONCLUSIONS

Higher Activin A quartiles were linked to increased risk of PRISm, along with lower hemoglobin and higher BUN levels. Additonally, elevated Activin A was a significant risk factor of all-cause mortality.

Inhibition of activin receptor 2 signalling ameliorates metabolic dysfunction-associated steatotic liver disease in western diet/L-NAME induced cardiometabolic disease

OBJECTIVE

Blockade of activin 2 receptor (ACVR2) signaling has been shown to improve insulin sensitivity and aid in weight loss. Inhibition of ACVR2 signaling restores cardiac function in multiple heart failure models. However, its potential in the treatment of obesity-related cardiometabolic disease remains unknown. Here, we investigated targeting ACVR2 signaling in cardiometabolic disease manifested with metabolic dysfunction-associated steatotic liver disease (MASLD).

METHODS

Mice were fed a high-fat, high-sugar diet combined with the administration of nitric oxide synthase inhibitor L-NAME in drinking water, which causes hypertensive stress. For the last eight weeks, the mice were treated with the soluble ACVR2B decoy receptor (sACVR2B-Fc).

RESULTS

sACVR2B-Fc protected against the development of comorbidities associated with cardiometabolic disease. This was most pronounced in the liver where ACVR2 blockade attenuated the development of MASLD including cessation of pro-fibrotic activation. It also significantly reduced total plasma cholesterol levels, impeded brown adipose tissue whitening, and improved cardiac diastolic function. In vitro, ACVR2 ligands activin A, activin B and GDF11 induced profibrotic signaling and the proliferation of human cardiac fibroblasts.

CONCLUSIONS

Blockade of ACVR2B exerts broad beneficial effects for therapy of cardiometabolic disease. By reducing obesity, ameliorating cardiovascular deterioration and restraining MASLD, blockade of ACVR2B signaling proves a potential target in MASLD and its comorbidities.

Impact of a hypocaloric dietary intervention on antral follicle dynamics in eumenorrheic women with obesity

STUDY QUESTION

Do antral follicle dynamics change in women with obesity and regular ovulatory cycles after a 6-month hypocaloric dietary intervention?

SUMMARY ANSWER

After a 6-month hypocaloric dietary intervention, women with obesity and regular ovulatory cycles displayed evidence of improved antral follicle dynamics defined by the emergence of more dominant follicles, larger ovulatory follicle diameter at selection, and increased luteal progesterone concentrations compared to pre-intervention.

WHAT IS KNOWN ALREADY

Precise events in antral folliculogenesis must occur in order for natural and regular monthly ovulation. In healthy women of reproductive age, antral follicles are recruited for growth in a wave-like fashion, wherein a subset of follicles are selected for preferential growth, and typically, one dominant follicle culminates in ovulation. Women with obesity and regular ovulatory cycles display evidence of suppressed antral follicle development, as evidenced by fewer recruitment events, fewer selectable and dominant follicles, smaller diameter of the ovulatory follicle at selection, and a higher prevalence of luteal phase defects. While improvements in gonadotropin and ovarian steroid hormone concentrations after weight loss have been documented in eumenorrheic women with obesity, the precise impact of weight loss on antral follicle dynamics has not been evaluated.

STUDY DESIGN, SIZE, DURATION

A pre-post pilot study of 12 women who participated in a 6-month hypocaloric dietary intervention.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Twelve women with obesity (total body fat ≥35%) underwent transvaginal ultrasonography and venipuncture every-other-day for one inter-ovulatory interval (IOI) both before (baseline) and during the final month (Month 7) of a six-month hypocaloric dietary intervention. Participants were aged 24-34 years and had a self-reported history of regular menstrual cycles (25-35 days). Follicle number and diameter (≥2 mm) were quantified at each study visit, and individual growth profiles for all follicles ≥7 mm were determined. Blood samples were assayed for reproductive hormones. Follicle dynamics and reproductive hormone concentrations were compared pre- and post-intervention. Further, post-intervention follicle and endocrine dynamics (Month 7 IOI) were compared to an age-matched reference cohort of lean women with regular ovulatory cycles (total body fat <35%, N = 21).

MAIN RESULTS AND THE ROLE OF CHANCE

Participants lost an average of 11% of their original body weight with the hypocaloric dietary intervention. More dominant follicles were detected (≥10 mm) at Month 7 compared to baseline (0. 3 ± 0.4 versus 0.4 ± 0.5 follicles, P = 0.001), and ovulatory follicles were selected at larger diameters post-intervention (7.3 ± 2.0 versus 10.9 ± 2.6 mm, P = 0.007). Luteal progesterone concentrations were increased at Month 7 compared to baseline (5.3 ± 3.65 versus 6.3 ± 4.74 ng/ml, P < 0.0001). However, risk for luteal phase dysfunction as judged by the prevalence of a luteal phase length <10 days, integrated luteal progesterone levels <80 ng/ml or peak progesterone <10 ng/ml did not differ pre- versus post-intervention (all, P > 0.05). In Month 7, follicle dynamics and endocrine profiles were similar to the reference cohort across all measures.

LIMITATIONS, REASONS FOR CAUTION

This study does not inform on the earliest stages of ovarian follicle development and is limited to providing knowledge on the later stages of antral follicle development. This study cannot fully address causation between weight loss and sustained improvements in antral follicle dynamics. The data cannot be extrapolated to comment on potential improvements in fertility and fecundity with weight loss. The small group sizes limit statistical power.

WIDER IMPLICATIONS OF THE FINDINGS

The increasing prevalence of obesity necessitates an understanding of the mechanisms that underlie potential improvements in reproductive health outcomes with weight loss. Women with obesity and regular ovulatory cycles who undertook a 6-month hypocaloric dietary intervention demonstrated improvements consistent with benefits of lifestyle intervention on reproductive health even in those without overt signs of reproductive dysfunction. Potential improvements in the cellular makeup of follicles, which may underlie the restoration of normal follicle development and amelioration of subfertility, require further investigation.

STUDY FUNDING/COMPETING INTEREST(S)

Cornell University, President's Council of Cornell Women, United States Department of Agriculture (Grant No. 8106), and National Institutes of Health (R01-HD0937848). B.Y.J. and H.V.B. were supported by doctoral training awards from the National Institutes of Health (T32-DK007158) and Canadian Institutes of Health Research (Grant No. 146182), respectively. The authors have no competing interests.

TRIAL REGISTRATION NUMBER

NCT01927432 and NCT01785719.

Plasma activin A rises with declining kidney function and is independently associated with mortality in patients with chronic kidney disease

Background

Plasma (p-)activin A is elevated in chronic kidney disease-mineral and bone disorder (CKD-MBD). Activin A inhibition ameliorates CKD-MBD complications (vascular calcification and bone disease) in rodent CKD models. We examined whether p-activin A was associated with major adverse cardiovascular events (MACE), all-cause mortality and CKD-MBD complications in CKD patients.

Methods

The study included 916 participants (741 patients and 175 controls) from the prospective Copenhagen CKD cohort. Comparisons of p-activin A with estimated glomerular filtration rate (eGFR), coronary and thoracic aorta Agatston scores, and bone mineral density (BMD) were evaluated by univariable linear regression using Spearman's rank correlation, analysis of covariance and ordinal logistic regression with adjustments. Association of p-activin A with rates of MACE and all-cause mortality was evaluated by the Aalen-Johansen or Kaplan-Meier estimator, with subsequent multiple Cox regression analyses.

Results

P-activin A was increased by CKD stage 3 (124-225 pg/mL, P < .001) and correlated inversely with eGFR (r = -0.53, P < 0.01). P-activin A was associated with all-cause mortality [97 events, hazard ratio 1.55 (95% confidence interval 1.04; 2.32), P < 0.05] after adjusting for age, sex, diabetes mellitus (DM) and eGFR. Median follow-up was 4.36 (interquartile range 3.64-4.75) years. The association with MACE was not significant after eGFR adjustment. Agatston scores and BMD were not associated with p-activin A.

Conclusion

P-activin A increased with declining kidney function and was associated with all-cause mortality independently of age, sex, DM and eGFR. No association with MACE, vascular calcification or BMD was demonstrated.

Sotatercept analog improves cardiopulmonary remodeling and pulmonary hypertension in experimental left heart failure

Pulmonary hypertension due to left heart disease (PH-LHD) is the most frequent manifestation of PH but lacks any approved treatment. Activin receptor type IIA-Fc fusion protein (ActRIIA-Fc) was found previously to be efficacious in experimental and human pulmonary arterial hypertension (PAH). Here we tested the hypothesis that ActRIIA-Fc improves pulmonary vascular remodeling and alleviates PH in models of PH-LHD, specifically in subtypes of heart failure with reduced ejection fraction (PH-HFrEF) and preserved ejection fraction (PH-HFpEF). Treatment with murine ActRIIA-Fc reduced cardiac remodeling and improved cardiac function in two mouse models of left heart disease without PH, confirming that this inhibitor of activin-class ligand signaling can exert cardioprotective effects in heart failure. In a mouse model of PH-HFrEF with prolonged pressure overload caused by transverse aortic constriction, ActRIIA-Fc treatment significantly reduced pulmonary vascular remodeling, pulmonary fibrosis, and pulmonary hypertension while exerting beneficial structural, functional, and histological effects on both the left and right heart. Additionally, in an obese ZSF1-SU5416 rat model of PH-HFpEF with metabolic dysregulation, therapeutic treatment with ActRIIA-Fc normalized SMAD3 overactivation in pulmonary vascular and perivascular cells, reversed pathologic pulmonary vascular and cardiac remodeling, improved pulmonary and cardiac fibrosis, alleviated PH, and produced marked functional improvements in both cardiac ventricles. Studies in vitro revealed that treatment with ActRIIA-Fc prevents an abnormal, glucose-induced, activin-mediated, migratory phenotype in human pulmonary artery smooth muscle cells, providing a mechanism by which ActRIIA-Fc could exert therapeutic effects in experimental PH-HFpEF with metabolic dysregulation. Our results demonstrate that ActRIIA-Fc broadly corrects cardiopulmonary structure and function in experimental PH-LHD, including models of PH-HFrEF and PH-HFpEF, leading to alleviation of PH under diverse pathophysiological conditions. These findings highlight the important pathogenic contributions of activin-class ligands in multiple forms of experimental PH and support ongoing clinical evaluation of human ActRIIA-Fc (sotatercept) in patients with PH-HFpEF.

Serum levels of Activin A: Marker of insulin resistance and cardiovascular risk in prediabetics

Background

A substantial proportion of health burden in diabetic individuals can be attributed to cardiovascular complications. The increasing risk of cardiovascular complications along the spectrum of dysglycemia warrants the need to devise novel markers for early assessment and management. Activin A is a multifunctional cytokine with an important role in glucose homeostasis and vascular diseases. It can thus serve as a guide for early identification of cardiovascular disease (CVD) risk in prediabetes.

Objective

The aim of the study was to measure serum levels of activin A in prediabetics, compare them with normoglycemic controls and find the correlation of activin A with markers of insulin resistance such as the homeostatic model assessment of insulin resistance (HOMA-IR).

Methods

Sixty prediabetic patients and similar age-, sex-, blood pressure-, and BMI-matched controls were recruited in the study. In both groups, serum levels of fasting blood glucose and post prandial glucose, glycated hemoglobin (HbA1c) and fasting insulin were measured. HOMA-IR values were calculated. Serum activin A levels were measured in both groups using ELISA. The obtained values were compared between the two groups.

Results

The median (IQR) of s. fasting insulin (mIU/L) in the case group was 15.3 (12.2-18.62) which was significantly higher than that in the control group, which was 6 (4.2-7.3). The median (IQR) of s. activin A (ng/mL) in the case group was 263.55 (227.18-279.56) which was significantly higher than that in the control group, which was 159.9 (150.73-178.75) (P < 0.001). There was a very strong positive correlation of s. activin A (ng/mL) with s. fasting insulin (mIU/L) and HOMA-IR (rho = 0.67 and 0.75, respectively, P < 0.001).

Conclusion

Activin A, if combined with other atherosclerotic markers, might improve the assessment of insulin resistance and cardiovascular risk in prediabetics and lead to focus on lifestyle modifications and preventive medical therapy, thereby contributing to the prevention of CVD-related mortality and morbidity in these patients.

Analysis of bacterial spectrum, activin A, and CD64 in chronic obstructive pulmonary disease patients complicated with pulmonary infections

BACKGROUND

Pulmonary infections often lead to poor prognoses in patients with chronic obstructive pulmonary disease (COPD). Activin A and CD64 play crucial pathological roles in the development of COPD.

AIM

To explore the bacterial spectrum via analysis of activing A levels, CD64 index, and related mechanisms in COPD patients complicated with pulmonary infection.

METHODS

Between March 2015 and January 2018, a total of 85 patients with COPD, who also suffered from pulmonary infections, were enrolled in this study as the pulmonary infection group. In addition, a total of 96 COPD patients, without pulmonary infection, were selected as the control group. Sputum samples of patients in the pulmonary infection group were cultivated for bacterial identification prior to administration of antibiotics. The neutrophil CD64 index was measured using flow cytometry, serum activin A levels were detected via an enzyme-linked immunosorbent assay, and activin A, Smad3, TLR4, MyD88, and NFκB protein expression was analyzed by Western blotting.

RESULTS

Gram-negative bacteria were identified in 57.65% of the sputum samples in the pulmonary infection group. The most prevalent Gram-negative species were Pseudomonas aeruginosa and Klebsiella pneumoniae. Conversely, Gram-positive bacteria were identified in 41.18% of the sputum samples in the pulmonary infection group. The most common Gram-positive species was Streptococcus pneumoniae. Fungi were identified in 1.17% of the sputum samples in the pulmonary infection group. The CD64 index was significantly higher in the pulmonary infection group (0.91 ± 0.38) than in the control group (0.23 ± 0.14, P < 0.001). The serum activin A levels were significantly higher in the pulmonary infection group (43.50 ± 5.22 ng/mL), compared to the control group (34.82 ± 4.16 ng/mL, P < 0.001). The relative expression levels of activin A, Smad3, TLR4, MyD88, and NFκB were all significantly higher in the pulmonary infection group, compared to the control group (all P < 0.001).

CONCLUSION

Pulmonary infections in COPD patients are mainly caused by Streptococcus pneumoniae, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Pulmonary infections can significantly increase neutrophil CD64 index and serum levels of activin A, thereby activating the activin A/Smad3 signaling pathway, which may positively regulate the TLR4/MyD88/NFκB signaling pathway.

Role of circulating molecules in age-related cardiovascular and metabolic disorders

Studies analyzing heterochronic parabiosis mice models showed that molecules in the blood of young mice rejuvenate aged mice. Therefore, blood-based therapies have become one of the therapeutic approaches to be considered for age-related diseases. Blood includes numerous biologically active molecules such as proteins, metabolites, hormones, miRNAs, etc. and accumulating evidence indicates some of these change their concentration with chronological aging or age-related disorders. The level of some circulating molecules showed a negative or positive correlation with all-cause mortality, cardiovascular events, or metabolic disorders. Through analyses of clinical/translation/basic research, some molecules were focused on as therapeutic targets. One approach is the supplementation of circulating anti-aging molecules. Favorable results in preclinical studies let some molecules to be tested in humans. These showed beneficial or neutral results, and some were inconsistent. Studies with rodents and humans indicate circulating molecules can be recognized as biomarkers or therapeutic targets mediating their pro-aging or anti-aging effects. Characterization of these molecules with aging, testing their biological effects, and finding mimetics of young systemic milieu continue to be an interesting and important research topic to be explored.

The association between serum activin A levels and albuminuria among community-dwelling middle-aged and older adults in Taiwan

Activin A, a cytokine belonging to the transforming growth factor-β family, has been shown to play pivotal roles in tissue remodeling after renal injury and is present in elevated levels in diabetic patients. However, the association between activin A and albuminuria remains unclear. We aimed to evaluate their association by using cross-sectional data from community-dwelling middle-aged and older adults in Taiwan. We assessed 466 participants (67% male; mean age 71 ± 13 years) from the I-Lan Longitudinal Aging study for whom data pertaining to serum activin A level and urine albumin-to-creatinine ratio (UACR) were available. Of these, 323 (69%) had normal albuminuria, 123 (26%) had microalbuminuria, and 20 (4%) had overt albuminuria. Patients with overt albuminuria and microalbuminuria had significantly higher activin A concentrations than those in the normal albuminuria group (p < 0.001). Circulating activin A was significantly correlated with multiple risk factors, including higher systolic blood pressure and higher UACR. Univariate and multivariate results indicated that activin A level was an independent variable for albuminuria. The cutoff value of 602 pg/mL of activin A demonstrated a sensitivity of 70.6% and specificity of 75.7% (AUC 0.774) in diagnosing overt albuminuria. In conclusion, middle-aged and older adults with elevated activin A levels were associated with a higher incidence of albuminuria.

Myostatin/Activin-A Signaling in the Vessel Wall and Vascular Calcification

A current hypothesis is that transforming growth factor-β signaling ligands, such as activin-A and myostatin, play a role in vascular damage in atherosclerosis and chronic kidney disease (CKD). Myostatin and activin-A bind with different affinity the activin receptors (type I or II), activating distinct intracellular signaling pathways and finally leading to modulation of gene expression. Myostatin and activin-A are expressed by different cell types and tissues, including muscle, kidney, reproductive system, immune cells, heart, and vessels, where they exert pleiotropic effects. In arterial vessels, experimental evidence indicates that myostatin may mostly promote vascular inflammation and premature aging, while activin-A is involved in the pathogenesis of vascular calcification and CKD-related mineral bone disorders. In this review, we discuss novel insights into the biology and physiology of the role played by myostatin and activin in the vascular wall, focusing on the experimental and clinical data, which suggest the involvement of these molecules in vascular remodeling and calcification processes. Moreover, we describe the strategies that have been used to modulate the activin downward signal. Understanding the role of myostatin/activin signaling in vascular disease and bone metabolism may provide novel therapeutic opportunities to improve the treatment of conditions still associated with high morbidity and mortality.

The Association between the Activin A Serum Level and Carotid Intima-Media Thickness in Chronic Kidney Disease Patients

Introduction

Chronic kidney disease (CKD) is associated with high mortality rates, mainly as a result of cardiovascular complications. Meanwhile, recent studies have suggested a role of a homodimer protein called activin A in chronic kidney disease-mineral and bone disorder (CKD-MBD) conditions that may exist in the vascular calcification and osteolytic process. Ultrasound examination of the carotid intima-media thickness (cIMT) is a noninvasive method to assess vascular calcification. This study aimed to analyze the relationship between the activin A serum level and cIMT in patients with CKD at Mohammad Hoesin Hospital, Palembang, Indonesia.

Methods

We conducted a hospital-based, cross-sectional study of consecutive CKD patients at the Department of Internal Medicine, Mohammad Hoesin Hospital, from July to November 2019. The level of activin A was measured by enzyme-linked immunosorbent assay. Meanwhile, cIMT measurements were collected by B-mode ultrasound imaging.

Results

A total of 55 patients with CKD were included in this investigation. The median serum activin A level in these patients was 236.17 (116.33–283) pg/mL, while the median cIMT was 0.8 (0.6–1.45) mm. A relationship between the serum activin A level and cIMT (r  =  0.449; p = 0.001) was observed. During multivariate analysis with linear regression, triglyceride (p = 0.049), phosphate (p = 0.005), and activin A (p = 0.020) serum levels were factors associated with cIMT.

Conclusion

In this study, a relationship between the activin A serum level and cIMT in patients with CKD was identified. Vascular calcification should be screened for in all CKD patients by the measurement of cIMT.

Circadian rhythm of activin A and related parameters of mineral metabolism in normal and uremic rats

Activin A is a new fascinating player in chronic kidney disease-mineral and bone disorder (CKD-MBD), which is implicated in progressive renal disease, vascular calcification, and osteodystrophy. Plasma activin A rises early in the progression of renal disease. Disruption of circadian rhythms is related to increased risk of several diseases and circadian rhythms are observed in mineral homeostasis, bone parameters, and plasma levels of phosphate and PTH. Therefore, we examined the circadian rhythm of activin A and CKD-MBD-related parameters (phosphate, PTH, FGF23, and klotho) in healthy controls and CKD rats (5/6 nephrectomy) on high-, standard- and low-dietary phosphate contents as well as during fasting conditions. Plasma activin A exhibited circadian rhythmicity in healthy control rats with fourfold higher values at acrophase compared with nadir. The rhythm was obliterated in CKD. Activin A was higher in CKD rats compared with controls when measured at daytime but not significantly when measured at evening/nighttime, stressing the importance of time-specific reference intervals when interpreting plasma values. Plasma phosphate, PTH, and FGF23 all showed circadian rhythms in control rats, which were abolished or disrupted in CKD. Plasma klotho did not show circadian rhythm. Thus, the present investigation shows, for the first time, circadian rhythm of plasma activin A. The rhythmicity is severely disturbed by CKD and is associated with disturbed rhythms of phosphate and phosphate-regulating hormones PTH and FGF23, indicating that disturbed circadian rhythmicity is an important feature of CKD-MBD.

Anti-inflammatory therapy for cardiovascular disease

Chronic subclinical inflammation is a central process in the pathogenesis of cardiovascular disease (CVD) and it has been linked with both the initiation and progression of atherosclerosis. Several pro-inflammatory cytokines, such as the C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) have been described as independent risk factors for coronary heart disease and promoters of atherogenesis. Thus, extensive research is being conducted to assess the role of anti-inflammatory therapy in the primary and secondary prevention of CVD. Our review aims to provide the clinical and scientific data pertaining to the effects of different anti-inflammatory agents administered in patients with CVD.