Serum activin-A as a predictive and prognostic marker in critically ill patients with sepsis

Correlation of serum VEGF-C, ANGPTL4, and activin A levels with frailty

BACKGROUND

Secretory factors linked to lymphogenesis, such as vascular endothelial growth factor C (VEGF-C), angiopoietin like protein 4 (ANGPTL4), and activin A (ACV-A), have been recognized as potential markers of chronic inflammatory status and age-related diseases. Furthermore, these factors may also be linked to frailty. The primary objective of this study was to examine the serum VEGF-C, ANGPTL4, and ACV-A levels in young individuals, healthy older individuals, and older individuals with pre-frailty and frailty, and to determine their association with pro-inflammatory factor levels.

METHODS

We conducted an observational study, enrolling a total of 210 older individuals and 20 young healthy volunteers. Participants were divided into four groups based on the Freid frailty phenotype: healthy young group, older patients without frailty group, pre-frail older group, and frail older group. Plasma and peripheral blood mononuclear cells (PBMCs) were collected from all four groups. ELISA was used to measure the serum levels of VEGF-C, ANGPTL4, ACV-A, and pro-inflammatory cytokines, while RT-qPCR was used to measure the transcription level of VEGF-C, ANGPTL4 and ACV-A in PBMCs.

RESULTS

In comparison to healthy young individuals and older participants without frailty, older participants with frailty exhibited lower renal function, higher serum levels and transcription levels of VEGF-C, ANGPTL4, ACV-A, and elevated levels of pro-inflammatory cytokines (CRP, IL-1β, and TNF-α). Multiple linear regression analysis revealed that serum levels of VEGF-C, ANGPTL4, and ACV-A were positively correlated with the frailty index, independent of age, eGFR, and comorbidities. Furthermore, the receiver operating characteristic (ROC) curve analysis demonstrated that serum levels of VEGF-C, ANGPTL4, and ACV-A have great accuracy in predicting frailty.

CONCLUSION

Elevated serum levels of VEGF-C, ANGPTL4, and ACV-A are associated with frailty status.

Activin A and Follistatin Serum Concentrations in Breast Augmentation Patients

Background: Capsular contracture is caused by an excessive fibrotic reaction similar as observed in other progressive fibrotic disorders. For their pathogenesis, several studies confirmed the importance of activins and follistatin. The aim of this study was to determine and analyze serum levels of Activin A and follistatin in patients with capsular contracture after aesthetic breast augmentation. Methods: The study included 361 female patients who underwent primary aesthetic breast augmentation, came for control examination after breast augmentation or for revision operation because of capsular contracture. Blood samples were taken and using a specific ELISA to determine the serum concentration levels of Activin A and Follistatin. Results: Ninety-six patients (n = 96), who developed a capsular contracture Baker ≥°III and underwent revision surgery were collected (capsular fibrosis group). One-hundred and fourteen patients (n = 114) were asymptomatic for capsular fibrosis Baker ≥°III after primary breast augmentation and 33 (n = 33) of them had developed no capsular fibrosis after more than 10 years (long-term group). For control group, blood samples were taken from 167 patients (n = 167) before primary aesthetic breast augmentation. Serum Activin A levels were significantly higher in the long-term Group compared with those in the capsular fibrosis- and the control groups. Follistatin levels were significantly lower in the capsular fibrosis group compared to the control- and the long-term groups. A small amount of control group patients (n = 16) developed a capsular fibrosis within 2 years after primary breast augmentation with significant lower follistatin levels. Retrospectively, they showed significantly lower serum follistatin levels than the control group even before the onset of capsular contracture. Conclusions: Capsular fibrosis has no effect on Activin A serum levels. In contrast, follistatin serum levels are lower in patients with capsular fibrosis. These results show that besides many other factors, a dysregulation of the Activin-follistatin axis may have importance on the pathogenesis of capsular contracture.

Activin A level is associated with physical function in critically ill patients

BACKGROUND

Activin A is a potent negative regulator of muscle mass elevated in critical illness. It is unclear whether muscle strength and physical function in critically ill humans are associated with elevated activin A levels.

OBJECTIVES

The objective of this study was to investigate the relationship between serum activin A levels, muscle strength, and physical function at discharge from the intensive care unit (ICU) and hospital.

METHODS

Thirty-six participants were recruited from two tertiary ICUs in Melbourne, Australia. Participants were included if they were mechanically ventilated for >48 h and expected to have a total ICU stay of >5 days. The primary outcome measure was the Six-Minute Walk Test distance at hospital discharge. Secondary outcome measures included handgrip strength, Medical Research Council Sum Score, Physical Function ICU Test Scored, Six-Minute Walk Test, and Timed Up and Go Test assessed throughout the hospital admission. Total serum activin A levels were measured daily in the ICU.

RESULTS

High peak activin A was associated with worse Six-Minute Walk Test distance at hospital discharge (linear regression coefficient, 95% confidence interval, p-value: -91.3, -154.2 to -28.4, p = 0.007, respectively). Peak activin A concentration was not associated with the secondary outcome measures.

CONCLUSIONS

Higher peak activin A may be associated with the functional decline of critically ill patients. Further research is indicated to examine its potential as a therapeutic target and a prospective predictor for muscle wasting in critical illness.

STUDY REGISTRATION

ACTRN12615000047594.

Acute Pancreatitis: Current Clinical Approaches, Molecular Pathophysiology, and Potential Therapeutics

OBJECTIVE

Severe acute pancreatitis (SAP), pancreatic inflammation leading to multiorgan failure, is associated with high morbidity and mortality. There is a critical need to identify novel therapeutic strategies to improve clinical outcomes for SAP patients.

MATERIALS AND METHODS

A comprehensive literature review was performed to identify current clinical strategies, known molecular pathophysiology, and potential therapeutic targets for SAP.

RESULTS

Current clinical approaches focus on determining which patients will likely develop SAP. However, therapeutic options are limited to supportive care and fluid resuscitation. The application of a novel 5-cytokine panel accurately predicting disease outcomes in SAP suggests that molecular approaches will improve impact of future clinical trials in AP.

CONCLUSIONS

Inflammatory outcomes in acute pancreatitis are driven by several unique molecular signals, which compound to promote both local and systemic inflammation. The identification of master cytokine regulators is critical to developing therapeutics, which reduce inflammation through several mechanisms.

The chemerin/CMKLR1 axis regulates intestinal graft-versus-host disease

Gastrointestinal graft-versus-host disease (GvHD) is a major cause of mortality and morbidity following allogeneic bone marrow transplantation (allo-BMT). Chemerin is a chemotactic protein that recruits leukocytes to inflamed tissues by interacting with ChemR23/CMKLR1, a chemotactic receptor expressed by leukocytes, including macrophages. During acute GvHD, chemerin plasma levels were strongly increased in allo-BM-transplanted mice. The role of the chemerin/CMKLR1 axis in GvHD was investigated using Cmklr1-KO mice. WT mice transplanted with an allogeneic graft from Cmklr1-KO donors (t-KO) had worse survival and more severe GvHD. Histological analysis demonstrated that the gastrointestinal tract was the organ mostly affected by GvHD in t-KO mice. The severe colitis of t-KO mice was characterized by massive neutrophil infiltration and tissue damage associated with bacterial translocation and exacerbated inflammation. Similarly, Cmklr1-KO recipient mice showed increased intestinal pathology in both allogeneic transplant and dextran sulfate sodium-induced colitis. Notably, the adoptive transfer of WT monocytes into t-KO mice mitigated GvHD manifestations by decreasing gut inflammation and T cell activation. In patients, higher chemerin serum levels were predictive of GvHD development. Overall, these results suggest that CMKLR1/chemerin may be a protective pathway for the control of intestinal inflammation and tissue damage in GvHD.

Role of Serum Inflammatory Cytokines in Sepsis Rats Following BMSCs Transplantation: Protein Microarray Analysis

Bone marrow stromal cells (BMSCs) have emerged as a potential therapy for sepsis, yet the underlying mechanisms remain unclear. In this study, we investigated the effects of BMSCs on serum inflammatory cytokines in a rat model of lipopolysaccharide (LPS)-induced sepsis. Sepsis was induced by intravenous injection of LPS, followed by transplantation of BMSCs. We monitored survival rates for 72 h and evaluated organ functions, histopathological changes, and cytokines expression. Sepsis rats showed decreased levels of white blood cells, platelets, lymphocyte ratio, and oxygen partial pressure, along with increased levels of neutrophil ratio, carbon dioxide partial pressure, lactic acid, alanine aminotransferase, and aspartate aminotransferase. Histologically, lung, intestine, and liver tissues exhibited congestion, edema, and infiltration of inflammatory cells. However, after BMSCs treatment, there was improvement in organ functions, histopathological injuries, and survival rates. Protein microarray analysis revealed significant changes in the expression of 12 out of 34 inflammatory cytokines. These findings were confirmed by enzyme-linked immunosorbent assay. Pro-inflammatory factors, such as interleukin-1β (IL-1β), IL-1α, tumor necrosis factor-α (TNF-α), tissue inhibitor of metal protease 1 (TIMP-1), matrix metalloproteinase 8 (MMP-8), Leptin, and L-selectin were upregulated in sepsis, whereas anti-inflammatory and growth factors, including IL-4, β-nerve growth factor (β-NGF), ciliary neurotrophic factor (CNTF), interferon γ (IFN-γ), and Activin A were downregulated. BMSCs transplantation led to a decrease in pro-inflammatory cytokines and an increase in anti-inflammatory and growth factors. We summarized relevant molecular signaling pathways that resulted from cytokines in BMSCs for treating sepsis. Our results illustrated that BMSCs could promote tissue repair and improve organ functions and survival rates in sepsis through modulating cytokine networks.

TGF-β Pathway Inhibition Protects the Diaphragm From Sepsis-Induced Wasting and Weakness in Rat

Sepsis is a frequent complication in patients in intensive care units (ICU). Diaphragm weakness, one of the most common symptoms observed, can lead to weaning problems during mechanical ventilation. Over the last couple of years, members of the transforming growth factor (TGF) β family, such as myostatin, activin A, and TGF-β1, have been reported to strongly trigger the activation of protein breakdown involved in muscle wasting. The aim of this study was to investigate the effect of TGF-β inhibitor LY364947 on the diaphragm during chronic sepsis.Rats were separated into four groups exposed to different experimental conditions: Control group, Septic group, Septic group with inhibitor from day 0 (LY D0), and Septic group with inhibitor from day 1 (LY D1). Sepsis was induced in rats by cecal ligation and puncture, and carried out for 7 days.Chronic sepsis was responsible for a decrease in body weight, food intake and diaphragm's mass. The inhibitor was able to abolish diaphragm wasting only in the LY D1 group. Similarly, LY364947 had a beneficial effect on the diaphragm contraction only for the LY D1 group. SMAD3 was over-expressed and phosphorylated within rats in the Septic group; however, this effect was reversed by LY364947. Calpain-1 and -2 as well as MAFbx were over-expressed within individuals in the Septic group. Yet, calpain-1 and MAFbx expressions were decreased by LY364947.With this work, we demonstrate for the first time that the inhibition of TGF-β pathway during chronic sepsis protects the diaphragm from wasting and weakness as early as one day post infection. This could lead to more efficient treatment and care for septic patients in ICU.

Activin A impairs ActRIIA+ neutrophil recruitment into infected skin of mice

Activin A levels are elevated during multiple severe infections and associated with an increased risk of death. However, the role of activin A in bacterial infection is still unclear. Here, we found that activin A levels were increased during S. aureus skin infection in mice. Administration of activin A increased the bacterial burden and promoted the spread of bacteria in vivo. Moreover, activin A inhibited neutrophil chemotaxis to N-formylmethionine-leucyl-phenylalanine via the type IIA activin receptor (ActRIIA) in vitro and impaired ActRIIA⁺ neutrophil recruitment to infection foci in vivo. Additionally, we identified a novel subpopulation of neutrophils, ActRIIA⁺ neutrophils, which exhibit superior phagocytic capacity compared to ActRIIA⁻ neutrophils and possess an N2-like immunoregulatory activity via secreting IL-10 and TGF-β. Taken together, these findings indicate that activin A inhibits the recruitment of ActRIIA⁺ neutrophils to infected foci, leading to the impairment of bacterial clearance, and thus may hamper early infection control.

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A novel activin A-responsitive subpopulation of neutrophils (ActRIIA⁺) was identified

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ActRIIA⁺ neutrophils exhibit N2-like immunoregulatory properties

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Activin A inhibits ActRIIA⁺ neutrophil recruitment to infected skin

Neutrophil activation in septic acute kidney injury: A post hoc analysis of the FINNAKI study

BACKGROUND

Inflammation, reflected by high plasma interleukin-6 concentration, is associated with acute kidney injury (AKI) in septic patients. Neutrophil activation has pathophysiological significance in experimental septic AKI. We hypothesized that neutrophil activation is associated with AKI in critically ill sepsis patients.

METHODS

We measured plasma (n = 182) and urine (n = 118) activin A (a rapidly released cytosolic neutrophil protein), interleukin-8 (a chemotactic factor for neutrophils), myeloperoxidase (a neutrophil biomarker released in tissues), and interleukin-6 on intensive care unit admission (plasma and urine) and 24 hours later (plasma) in sepsis patients manifesting their first organ dysfunction between 24 hours preceding admission and the second calendar day in intensive care unit. AKI was defined by the Kidney Disease: Improving Global Outcomes criteria.

RESULTS

Plasma admission interleukin-8 (240 [60-971] vs 50 [19-164] pg/mL, P < .001) and activin A (845 [554-1895] vs 469 [285-862] pg/mL, P < .001) were but myeloperoxidase (169 [111-300] vs 144 [88-215] ng/mL, P = .059) was not higher among patients with AKI compared with those without. Urine admission interleukin-8 (50.4 [19.8-145.3] vs 9.5 [2.7-28.7] ng/mL, P < .001) and myeloperoxidase (7.7 [1.5-12.6] vs 1.9 [0.4-6.9] ng/mL, P < .001) were but activin A (9.7 [1.4-42.6] vs 4.0 [0.0-33.0] ng/mL, P = .064) was not higher in AKI than non-AKI patients. Urine myeloperoxidase correlated with urine interleukin-8 (R = .627, P < .001) but not with plasma myeloperoxidase (R = .131, P = .158).

CONCLUSION

Interleukin-8 in plasma and urine was associated with septic AKI. Elevated plasma activin A indicates intravascular neutrophil activation in septic AKI. Concomitant plasma and urine myeloperoxidase measurements suggest neutrophil accumulation into injured kidneys.

Diagnostic and prognostic values of serum activin-a levels in patients with acute respiratory distress syndrome

Background

We aimed to evaluate whether serum activin-A levels are elevated and have any value in predicting severity and prognosis in acute respiratory distress syndrome (ARDS).

Methods

Retrospective cohort study was performed with patients who were admitted to MICU with diagnosis of ARDS and have serum samples stored within 48 h of Intensive care unit (ICU) admission between March 2013 and December 2016 at a single tertiary referral hospital. Serum activin-A levels were measured with ELISA kit, and were compared with those of normal healthy control and non-ARDS sepsis patients.

Results

Total 97 ARDS patients were included for the study. Levels of Activin-A were elevated in ARDS patients compared to those of healthy controls (Log-transformed activin-A levels 2.89 ± 0.36 vs. 2.34 ± 0.11, p < 0.001, absolute activin-A levels 1525.6 ± 1060.98 vs. 225.9 ± 30.1, p = 0.016) and non-ARDS sepsis patients (Log-transformed activin-A levels 2.89 ± 0.36 vs. 2.73 ± 0.34, p = 0.002, Absolute activin-A levels 1525.6 ± 1060.98 vs. 754.8 ± 123.5 pg/mL, p = 0.036). When excluding five outliers with extremely high activin-A levels, activin-A showed statistically significant correlation with in-hospital mortalities (In-hospital survivors 676.2 ± 407 vs. non-survivors 897.9 ± 561.9 pg/mL, p = 0.047). In predicting in-hospital mortality, serum activin-A concentrations showed superior area under curve compared to that of Acute physiologic and chronic health evaluation II scores (0.653; 95% CI [0541, 0.765] vs. 0.591, 95% CI [0.471, 0.710]). With cut-off level of 708 pg/mL, those with high serum activin-A levels had more than twofold increased risk of in-hospital mortalities. However, those relations were missing when outliers were in.

Conclusions

Serum activin-A levels in ARDS patients are elevated. However, its levels are weakly associated with ARDS outcomes.

Electronic supplementary material

The online version of this article (10.1186/s12890-019-0879-6) contains supplementary material, which is available to authorized users.

Serum biomarkers for predicting overall survival and early mortality in older patients with metastatic solid tumors

OBJECTIVES

We aimed to explore serum biomarkers for predicting survival of older patients with metastatic solid tumors who received first line palliative chemotherapy.

MATERIALS AND METHODS

Serum samples were prospectively collected before first-line chemotherapy at 11 academic centers in Korea. All patients were participants in a prospective cohort study of older patients with metastatic solid tumors. Serum levels of C-reactive protein (CRP), CXCL10, SIRT1, VEGF-A, activin A, C-terminal telopeptide of type I collagen (CTx), total 25-hydroxyvitamin D were measured by ELISA and interleukin-6 (IL-6), myostatin, irisin, FGF-19, FGF-21, FGF-23 by Luminex multiplex assay. Overall survival (OS) was determined.

RESULTS

Serum samples from 138 patients (median age: 75 years, range: 70-92 years) were collected from February 2014 to December 2016. During a median follow up time of 13.8 months, 73 (52.9%) patients died. Among 13 serum markers, CRP (log-rank, P = 0.009), activin A (P = 0.007), and myostatin (P = 0.047) were significantly correlated with OS in univariate analyses. Activin A (hazard ratio [HR] 2.22, 95% confidence interval [CI] 1.32-3.72; P = 0.003) and myostatin (HR 3.02, 95% CI 1.39-6.57; P = 0.005) were significantly associated with OS after adjustment for other clinical factors. In predicting early (6-month) mortality, two inflammatory markers, IL-6 and CRP, were included in the decision-tree model.

CONCLUSION

In older patients with cancer, high serum concentrations of activin A and myostatin were predictive of poor OS. IL-6 and CRP might be useful to select older patients at risk of early mortality. These markers could be incorporated into predictive tools for clinical decision-making and warrant further investigation.

Activin A in Mammalian Physiology

Activins are dimeric glycoproteins belonging to the transforming growth factor beta superfamily and resulting from the assembly of two beta subunits, which may also be combined with alpha subunits to form inhibins. Activins were discovered in 1986 following the isolation of inhibins from porcine follicular fluid, and were characterized as ovarian hormones that stimulate follicle stimulating hormone (FSH) release by the pituitary gland. In particular, activin A was shown to be the isoform of greater physiological importance in humans. The current understanding of activin A surpasses the reproductive system and allows its classification as a hormone, a growth factor, and a cytokine. In more than 30 yr of intense research, activin A was localized in female and male reproductive organs but also in other organs and systems as diverse as the brain, liver, lung, bone, and gut. Moreover, its roles include embryonic differentiation, trophoblast invasion of the uterine wall in early pregnancy, and fetal/neonate brain protection in hypoxic conditions. It is now recognized that activin A overexpression may be either cytostatic or mitogenic, depending on the cell type, with important implications for tumor biology. Activin A also regulates bone formation and regeneration, enhances joint inflammation in rheumatoid arthritis, and triggers pathogenic mechanisms in the respiratory system. In this 30-yr review, we analyze the evidence for physiological roles of activin A and the potential use of activin agonists and antagonists as therapeutic agents.

Research Progress on the Role and Mechanism of Action of Activin A in Brain Injury

Activin A belongs to the transforming growth factor superfamily and has a variety of biological functions. Studies have revealed that activin A can regulate the body's immune and inflammatory responses and participate in the regulation of cell death. In addition, activin A also has neurotrophic function and plays an important role in the repair of brain damage. This article summarizes recent advances in understanding the role and mechanism of action of activin A in brain injury and provides new hints into the application of activin A in the treatment of brain injury.

Activin A regulates activation of mouse neutrophils by Smad3 signalling

Activin A, a member of the transforming growth factor beta superfamily, acts as a pro-inflammatory factor in acute phase response, and influences the pathological progress of neutrophil-mediated disease. However, whether activin A can exert an effect on the activities of neutrophils remains unclear. In this study, we found that the release of activin A was enhanced from neutrophils of mouse when stimulated with lipopolysaccharide. Furthermore, neutrophils were not only the source of activin A but also the target cells in response to activin A, in which canonical activin signalling components existed, and levels of ACTRIIA, SMAD3 and p-SMAD3 proteins were elevated in activin A-treated neutrophils. Next, the role of activin A was determined in regulation of neutrophils activities. Our data revealed that activin A induced O₂⁻ release and reactive oxygen species production, promoted IL-6 release, and enhanced phagocytosis, but failed to attract neutrophils migrating across the trans-well membrane. Moreover, we found that effect of activin A on IL-6 release from the peritoneal neutrophils of mouse was significantly attenuated by in vivo Smad3 knockdown. In summary, these data demonstrate that activin A can exert an effect on neutrophils activation in an autocrine/paracrine manner through Smad3 signalling, suggesting that activin A is an important regulator of neutrophils.