Current IGFBP-Related Biomarker Research in Cardiovascular Disease-We Need More Structural and Functional Information in Clinical Studies

Circadian misalignment disrupts biomarkers of cardiovascular disease risk and promotes a hypercoagulable state

The circadian system regulates 24-h time-of-day patterns of cardiovascular physiology, with circadian misalignment resulting in adverse cardiovascular risk. Although many proteins in the coagulation-fibrinolysis axis show 24-h time-of-day patterns, it is not understood if these temporal patterns are regulated by circadian or behavioral (e.g., sleep and food intake) cycles, or how circadian misalignment influences these patterns. Thus, we utilized a night shiftwork protocol to analyze circadian versus behavioral cycle regulation of 238 plasma proteins linked to cardiovascular physiology. Six healthy men aged 26.2 ± 5.6 years (mean ± SD) completed the protocol involving two baseline days with 8-h nighttime sleep opportunities (circadian alignment), a transition to shiftwork day, followed by 2 days of simulated night shiftwork with 8-h daytime sleep opportunities (circadian misalignment). Plasma was collected for proteomics every 4 h across 24 h during baseline and during daytime sleep and the second night shift. Cosinor analyses identified proteins with circadian or behavioral cycle-regulated 24-h time-of-day patterns. Five proteins were circadian regulated (plasminogen activator inhibitor-1, angiopoietin-2, insulin-like growth factor binding protein-4, follistatin-related protein-3, and endoplasmic reticulum resident protein-29). No cardiovascular-related proteins showed regulation by behavioral cycles. Within the coagulation pathway, circadian misalignment decreased tissue factor pathway inhibitor, increased tissue factor, and induced a 24-h time-of-day pattern in coagulation factor VII (all FDR < 0.10). Such changes in protein abundance are consistent with changes observed in hypercoagulable states. Our analyses identify circadian regulation of proteins involved in cardiovascular physiology and indicate that acute circadian misalignment could promote a hypercoagulable state, possibly contributing to elevated cardiovascular disease risk among shift workers.

Insulin-Like Growth Factor Binding Protein 2 Drives Neurodegeneration in Parkinson's Disease: Insights From In Vivo and In Vitro Studies

AIMS

Insulin-like growth factor binding protein 2 (IGFBP2) is implicated in various neurodegenerative diseases. However, its role in Parkinson's disease (PD) is unclear.

METHODS

PD rat model was established by 6-OHDA injection. After 3 weeks, mRNA-seq was conducted. Rats received rIGFBP2 via intra-MFB injection 6 h prior to 6-OHDA infusion, and the effect of IGFBP2 in PD rats was investigated by western blotting, IHC, specific kits, JC-1 staining, and TUNEL analysis. In vitro, PC12 cells were treated with 6-OHDA, and CCK-8, specific kits, Hoechst 33258 staining, Western blotting, and JC-1 staining were performed to assess the IGFBP2's role.

RESULTS

mRNA-seq revealed DEGs in PD, with attention to downregulated IGFBP2. rIGFBP2 treatment aggravated neurobehavioral deficits, decreased TH expression, Ψm, ATP level and SOD, GSH-Px activities but increased α-synuclein, ROS, MDA, mitochondrial cytochrome c contents, cell apoptosis in 6-OHDA-lesioned rats, which might be mediated through inactivating IGF-1R/AKT pathway. In 6-OHDA-treated PC12 cells, rIGFBP2 aggravated cell injury, demonstrated by decreased cell viability and increased apoptosis, oxidative stress, and mitochondrial dysfunction. Co-treatment with rIGFBP2 and rIGF-1 partially reversed the effect of rIGFBP2 on cell damage.

CONCLUSION

IGFBP2 exacerbates neurodegeneration in PD through increasing oxidative stress, mitochondrial dysfunction, and apoptosis via inhibiting IGF-1R/AKT pathway.

Incident heart failure in chronic kidney disease: proteomics informs biology and risk stratification

BACKGROUND AND AIMS

Incident heart failure (HF) among individuals with chronic kidney disease (CKD) incurs hospitalizations that burden patients and health care systems. There are few preventative therapies, and the Pooled Cohort equations to Prevent Heart Failure (PCP-HF) perform poorly in the setting of CKD. New drug targets and better risk stratification are urgently needed.

METHODS

In this analysis of incident HF, SomaScan V4.0 (4638 proteins) was analysed in 2906 participants of the Chronic Renal Insufficiency Cohort (CRIC) with validation in the Atherosclerosis Risk in Communities (ARIC) study. The primary outcome was 14-year incident HF (390 events); secondary outcomes included 4-year HF (183 events), HF with reduced ejection fraction (137 events), and HF with preserved ejection fraction (165 events). Mendelian randomization and Gene Ontology were applied to examine causality and pathways. The performance of novel multi-protein risk models was compared to the PCP-HF risk score.

RESULTS

Over 200 proteins were associated with incident HF after adjustment for estimated glomerular filtration rate at P < 1 × 10-5. After adjustment for covariates including N-terminal pro-B-type natriuretic peptide, 17 proteins remained associated at P < 1 × 10-5. Mendelian randomization associations were found for six proteins, of which four are druggable targets: FCG2B, IGFBP3, CAH6, and ASGR1. For the primary outcome, the C-statistic (95% confidence interval [CI]) for the 48-protein model in CRIC was 0.790 (0.735, 0.844) vs. 0.703 (0.644, 0.762) for the PCP-HF model (P = .001). C-statistic (95% CI) for the protein model in ARIC was 0.747 (0.707, 0.787).

CONCLUSIONS

Large-scale proteomics reveal novel circulating protein biomarkers and potential mediators of HF in CKD. Proteomic risk models improve upon the PCP-HF risk score in this population.

IGF Signaling in the Heart in Health and Disease

One of the most vital processes of the body is the cardiovascular system's proper operation. Physiological processes in the heart are regulated by the balance of cardioprotective and pathological mechanisms. The insulin-like growth factor system (IGF system, IGF signaling pathway) plays a pivotal role in regulating growth and development of various cells and tissues. In myocardium, the IGF system provides cardioprotective effects as well as participates in pathological processes. This review summarizes recent data on the role of IGF signaling in cardioprotection and pathogenesis of various cardiovascular diseases, as well as analyzes severity of these effects in various scenarios.

Insulin-like Growth Factor-Binding Protein 2 in Severe Aortic Valve Stenosis and Pulmonary Hypertension: A Gender-Based Perspective

Severe aortic valve stenosis (AS) and pulmonary hypertension (PH) are life-threatening cardiovascular conditions, necessitating early detection and intervention. Recent studies have explored the role of Insulin-like Growth Factor-Binding Protein 2 (IGF-BP2) in cardiovascular pathophysiology. Understanding its involvement may offer novel insights into disease mechanisms and therapeutic targets for these conditions. A total of 102 patients (46 female, 56 male) with severe AS undergoing a transcatheter aortic valve replacement (TAVR) in a single-center study were classified using echocardiography tests to determine systolic pulmonary artery pressure (sPAP) and the presence (sPAP ≥ 40 mmHg) or absence (sPAP < 40 mmHg) of PH. Additionally, serial laboratory determinations of IGF-BP2 before, and at 24 h, 96 h, and 3 months after intervention were conducted in all study participants. Considering the entire cohort, patients with PH had significant and continuously higher serum IGF-BP2 concentrations over time than patients without PH. After subdivision by sex, it could be demonstrated that the above-mentioned results were only verifiable in males, but not in females. In the male patients, baseline IGF-BP2 levels before the TAVR was an isolated risk factor for premature death after intervention and at 1, 3, and 5 years post-intervention. The same was valid for the combination of male and echocardiographically established PH patients. The predictive role of IGF-BP2 in severe AS and concurrent PH remains unknown. A more profound comprehension of IGF-BP2 mechanisms, particularly in males, could facilitate the earlier consideration of the TAVR as a more effective and successful treatment strategy.

Identifying plasma proteomic signatures from health to heart failure, across the ejection fraction spectrum

Circulating proteins may provide insights into the varying biological mechanisms involved in heart failure (HF) with preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF). We aimed to identify specific proteomic patterns for HF, by comparing proteomic profiles across the ejection fraction spectrum. We investigated 4210 circulating proteins in 739 patients with normal (Stage A/Healthy) or elevated (Stage B) filling pressures, HFpEF, or ischemic HFrEF (iHFrEF). We found 2122 differentially expressed proteins between iHFrEF-Stage A/Healthy, 1462 between iHFrEF-HFpEF and 52 between HFpEF-Stage A/Healthy. Of these 52 proteins, 50 were also found in iHFrEF vs. Stage A/Healthy, leaving SLITRK6 and NELL2 expressed in lower levels only in HFpEF. Moreover, 108 proteins, linked to regulation of cell fate commitment, differed only between iHFrEF-HFpEF. Proteomics across the HF spectrum reveals overlap in differentially expressed proteins compared to stage A/Healthy. Multiple proteins are unique for distinguishing iHFrEF from HFpEF, supporting the capacity of proteomics to discern between these conditions.

The IGF-PAPP-A-Stanniocalcin Axis in Serum and Ascites Associates with Prognosis in Patients with Ovarian Cancer

Pregnancy-associated plasma protein-A (PAPP-A) and PAPP-A2 modulate insulin-like growth factor (IGF) action and are inhibited by the stanniocalcins (STC1 and STC2). We previously demonstrated increased PAPP-A and IGF activity in ascites from women with ovarian carcinomas. In this prospective, longitudinal study of 107 women with ovarian cancer and ascites accumulation, we determined corresponding serum and ascites levels of IGF-1, IGF-2, PAPP-A, PAPP-A2, STC1, and STC2 and assessed their relationship with mortality. As compared to serum, we found highly increased ascites levels of PAPP-A (51-fold) and PAPP-A2 (4-fold). Elevated levels were also observed for IGF-1 (12%), STC1 (90%) and STC2 (68%). In contrast, IGF-2 was reduced by 29% in ascites. Patients were followed for a median of 38.4 months (range: 45 days to 8.9 years), during which 73 patients (68.2%) died. Overall survival was longer for patients with high serum IGF-1 (hazard ratio (HR) per doubling in protein concentration: 0.60, 95% CI: 0.40-0.90). However, patients with high ascites levels of IGF-1 showed a poorer prognosis (HR: 2.00 (1.26-3.27)). High serum and ascites IGF-2 levels were associated with increased risk of mortality (HR: 2.01 (1.22-3.30) and HR: 1.78 (1.24-2.54), respectively). Similarly, serum PAPP-A2 was associated with mortality (HR: 1.26 (1.08-1.48)). Our findings demonstrate the presence and activity of the IGF system in the local tumor ecosystem, which is likely a characteristic feature of malignant disease and plays a role in its peritoneal dissemination. The potential clinical implications are supported by our finding that serum levels of the proteins are associated with patient prognosis.

The effects of IGF-1 and IGFBP-2 treatments on the atherosclerosis in the aorta and the coronary arteries of the high cholesterol diet-fed rabbits

Several studies have demonstrated suppression of aortic atherosclerosis by insulin like growth factor-1 (IGF-1) in hypercholesterolemic rabbits. Though a recent study has reported that IGF-1 exerts anti-atherogenic effects in coronary arteries, the mechanisms of IGF-1 in coronary arteries need to be further verified. Studies about insulin like growth factor binding protein-2 (IGFBP-2) in atherosclerosis are rarely. The objective of this study is to examine the effects of IGF-1 and IGFBP-2 on the atherosclerosis development in the aorta and coronary arteries of the high-cholesterol diet (HCD)-fed rabbits. New Zealand white rabbits were fed either normal chow (n = 5) or a diet containing 1.0 % cholesterol (n = 18) for 12 weeks. Cholesterol-fed rabbits were given IGF-1 or IGFBP-2 or saline intravenously (each n = 6) for 10 weeks. The results revealed that IGF-1 decreased total cholesterol (TC) and low-density lipoprotein (LDL) levels (p < 0.05), whereas IGFBP-2 did not. IGF-1 significantly attenuated atherosclerotic lesions and reduced accumulated macrophages within the coronary artery plaques, whereas IGFBP-2 deteriorated these changes. Moreover, IGF-1 reduced serum platelet-activating factor acetylhydrolase levels, C reactive protein (CRP), and inhibited the protein expression levels of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6). IGFBP-2 elevated serum 8-hydroxy-2'-deoxyguanosine levels, CRP, and promoted the protein expression levels of TNF-α and IL-6. In conclusion, IGF-1 can substantially suppress plaque formation in coronary arteries with a marked inhibition of macrophage accumulation likely via its anti-inflammatory properties, whereas IGFBP-2 plays an opposite effect on atherosclerosis. The present study highlighted a theoretical basis for pharmacological treatment of atherosclerosis.

Proteomics Analysis of Serum Reveals Potential Biomarkers for Heart Failure Patients with Phlegm-Blood Stasis Syndrome

Heart failure (HF), a complex clinical syndrome, has become a global burden on health and economics around the world. Phlegm-blood stasis syndrome, one of the Traditional Chinese Medicine (TCM) syndrome differentiation, is the core pathogenesis dynamically throughout the occurrence, development, and prognosis of HF. Biomarkers having high sensitivity and specificity are highly demanded to facilitate the accurate differentiation of HF patients with phlegm-blood stasis syndrome. In the present study, serum samples were collected from 20 healthy controls and 40 HF patients (20 with and 20 without phlegm-blood stasis syndrome). We implemented data-independent acquisition mass spectrometry (DIA-MS) for discovery and parallel reaction monitoring (PRM) for validation of biomarkers for heart failure with phlegm-blood stasis syndrome. A total of 84 different proteins were found in the HF with phlegm-blood stasis syndrome (HF-TY) group compared with healthy controls. 37 candidate proteins were selected for the PRM assay, and five validated proteins with high sensitivity and specificity, including insulin-like growth factor-binding protein 4 (IGFBP4), β-2-microglobulin (B2M), dystroglycan (DAG1), immunoglobulin J chain (JCHAIN), and kallikrein B1 (KLKB1), were considered potential biomarkers for heart failure patients with phlegm-blood stasis syndrome. Newly identified biomarkers might provide insights into the diagnosis and treatment of HF with TCM syndrome differentiation.

Associations between insulin-like growth factor binding protein-2 and insulin sensitivity, metformin, and mortality in persons with T2D

AIMS

Serum insulin-like growth factor binding protein-2 (IGFBP-2) is low in persons with type 2 diabetes mellitus (T2D) and possibly regulated by metformin. Counter-intuitively, high IGFBP-2 associates with mortality. We investigated the association between IGFBP-2, metformin-treatment, and indices of insulin sensitivity, and assessed IGFBP-2 in relation to prior comorbidity and mortality during five-year follow-up.

METHODS

The study included 859 treatment-naive and 558 metformin-treated persons enrolled in the Danish Centre for Strategic Research in T2D and followed for 4.9 (3.9-5.9) years through national health registries. All proteins were determined in serum collected at enrollment.

RESULTS

Following adjustment for age, metformin-treated and treatment-naive persons has similar IGFBP-2 levels. Low IGFBP-2 level was associated with increased BMI, fasting glucose, and C-peptide. IGFBP-2 was higher in the 437 persons who had comorbidities at enrollment than in those with T2D only (343 (213;528) vs. 242 (169;378) ng/mL). During follow-up, 87 persons died, and IGFBP-2 predicted mortality with an unadjusted HR (95% CI) per doubling in IGFBP-2 concentration of 2.62 (2.04;3.37) and a HR of 2.21 (1.61;3.01) following full adjustment.

CONCLUSIONS

In T2D, high IGFBP-2 associates with low glucose and insulin secretion, is unaffected by metformin treatment, and associates with risk of prior comorbidity and mortality.

Insulin growth factor axis and cardio-renal risk in diabetic kidney disease: an analysis from the CREDENCE trial

BACKGROUND

The insulin-like growth factors (IGF) play a crucial role in regulating cellular proliferation, apoptosis, and key metabolic pathways. The ratio of IGF-1 to IGF binding protein-3 (IGFBP-3) is an important factor in determining IGF-1 bioactivity. We sought to investigate the association of IGF-1 and IGFBP-3 with cardio-renal outcomes among persons with type 2 diabetes.

METHODS

Samples were available from 2627 individuals with type 2 diabetes and chronic kidney disease that were randomized to receive canagliflozin or placebo and were followed up for incident cardio-renal events. Primary outcome was defined as a composite of end-stage kidney disease, doubling of the serum creatinine level, or renal/cardiovascular death. IGF-1 and IGFBP-3 were measured at baseline, Year-1 and Year-3. Elevated IGF-1 level was defined according to age-specific cutoffs. Cox proportional hazard regression was used to investigate the association between IGF-1 level, IGFBP-3, and the ratio of IGF-1/IGFBP-3 with clinical outcomes.

RESULTS

Elevated IGF-1 was associated with lower glomerular filtration rate at baseline. Treatment with canagliflozin did not significantly change IGF-1 and IGFBP-3 concentrations by 3 years (p-value > 0.05). In multivariable models, elevated IGF-1 (above vs below age-specific cutoffs) was associated with the primary composite outcome (incidence rate:17.8% vs. 12.7% with a hazard ratio [HR]: 1.52; 95% confidence interval CI 1.09-2.13;P: 0.01), renal composite outcome (HR: 1.65; 95% CI 1.14-2.41; P: 0.01), and all-cause mortality (HR: 1.52; 95% CI 1.00-2.32; P; 0.05). Elevations in log IGFBP-3 did not associate with any clinical outcomes. Increase in log IGF-1/IGFBP-3 ratio was also associated with a higher risk of the primary composite outcome (HR per unit increase: 1.57; 95% CI 1.09-2.26; P; 0.01).

CONCLUSIONS

These results further suggest potential importance of IGF biology in the risk for cardio-renal outcomes in type 2 diabetes. SGLT2 inhibition has no impact on the biology of IGF despite its significant influence on outcomes.

TRIAL REGISTRATION

CREDENCE; ClinicalTrials.gov Identifier: NCT02065791.

The Role of Epicardial Adipose Tissue-Derived MicroRNAs in the Regulation of Cardiovascular Disease: A Narrative Review

Cardiovascular diseases have been leading cause of death worldwide for many decades, and obesity has been acknowledged as a risk factor for cardiovascular diseases. In the present review, human epicardial adipose tissue-derived miRNAs reported to be differentially expressed under pathologic conditions are discussed and summarized. The results of the literature review indicate that some of the epicardial adipose tissue-derived miRNAs are believed to be cardioprotective, while some others show quite the opposite effects depending on the underlying pathologic conditions. Furthermore, they suggest that that the epicardial adipose tissue-derived miRNAs have great potential as both a diagnostic and therapeutic modality. Nevertheless, mainly due to highly limited availability of human samples, it is very difficult to make any generalized claims on a given miRNA in terms of its overall impact on the cardiovascular system. Therefore, further functional investigation of a given miRNA including, but not limited to, the study of its dose effect, off-target effects, and potential toxicity is required. We hope that this review can provide novel insights to transform our current knowledge on epicardial adipose tissue-derived miRNAs into clinically viable therapeutic strategies for preventing and treating cardiovascular diseases.

New insights on the cardiovascular effects of IGF-1

INTRODUCTION

Cardiovascular (CV) disorders are steadily increasing, making them the world's most prevalent health issue. New research highlights the importance of insulin-like growth factor 1 (IGF-1) for maintaining CV health.

METHODS

We searched PubMed and MEDLINE for English and non-English articles with English abstracts published between 1957 (when the first report on IGF-1 identification was published) and 2022. The top search terms were: IGF-1, cardiovascular disease, IGF-1 receptors, IGF-1 and microRNAs, therapeutic interventions with IGF-1, IGF-1 and diabetes, IGF-1 and cardiovascular disease. The search retrieved original peer-reviewed articles, which were further analyzed, focusing on the role of IGF-1 in pathophysiological conditions. We specifically focused on including the most recent findings published in the past five years.

RESULTS

IGF-1, an anabolic growth factor, regulates cell division, proliferation, and survival. In addition to its well-known growth-promoting and metabolic effects, there is mounting evidence that IGF-1 plays a specialized role in the complex activities that underpin CV function. IGF-1 promotes cardiac development and improves cardiac output, stroke volume, contractility, and ejection fraction. Furthermore, IGF-1 mediates many growth hormones (GH) actions. IGF-1 stimulates contractility and tissue remodeling in humans to improve heart function after myocardial infarction. IGF-1 also improves the lipid profile, lowers insulin levels, increases insulin sensitivity, and promotes glucose metabolism. These findings point to the intriguing medicinal potential of IGF-1. Human studies associate low serum levels of free or total IGF-1 with an increased risk of CV and cerebrovascular illness. Extensive human trials are being conducted to investigate the therapeutic efficacy and outcomes of IGF-1-related therapy.

DISCUSSION

We anticipate the development of novel IGF-1-related therapy with minimal side effects. This review discusses recent findings on the role of IGF-1 in the cardiovascular (CVD) system, including both normal and pathological conditions. We also discuss progress in therapeutic interventions aimed at targeting the IGF axis and provide insights into the epigenetic regulation of IGF-1 mediated by microRNAs.

Quantitative Data-Independent Acquisition Mass Spectrometry Proteomics and Weighted Correlation Network Analysis of Plasma Samples for the Discovery of Chronic Kidney Disease-Specific Atherosclerosis Risk Factors

Chronic kidney disease (CKD) accelerates atherosclerosis. The mechanism of CKD-related atherosclerosis is complex, and CKD-specific risk factors may contribute to this process in addition to traditional risk factors such as hypertension, diabetes, and hypercholesterolemia. In the present study, to discover CKD-specific atherosclerosis risk factors, a total of 62 patients with different stages of kidney function were enrolled. All patients underwent coronary angiographies and the severity of coronary atherosclerosis was defined by the SYNTAX score. Patients were divided into different groups according to their kidney function levels and coronary atherosclerosis severity. Data-independent acquisition mass spectrometry was used to identify differentially expressed proteins (DEPs) in the plasma samples, and weighted correlation network analysis (WGCNA) was employed to identify significant protein modules and hub proteins related to CKD-specific atherosclerosis. The results showed that 10 DEPs associated with atherosclerosis were found in the comparative groups with modest and severe CKD. Through WGCNA, 1768 proteins were identified and 8 protein modules were established. Enrichment analyses of protein modules revealed functional clusters mainly associated with inflammation and the complement and coagulation cascade as atherosclerosis developed under CKD conditions. The results may help to better understand the mechanisms of CKD-related atherosclerosis and guide future research on developing treatments for CKD-related atherosclerosis.

CT-IGFBP-4 as a Predictive Novel Biomarker of Ischemic Cardiovascular Events and Mortality: A Systematic Review

Methods

The electronic databases PubMed, medRxiv, ScienceDirect, and Google Scholar were searched for relevant literature from inception to the 10^th of December, 2021. Thus, retrieved literature was screened by title and abstract, followed by full-text screening based on the eligibility criteria. The risk of bias was accessed using the quality in prognostic studies (QUIPSs) tool. The data on cardiovascular outcomes about CT-IGFBP-4 levels were studied and the results were synthesized.

Results

Five studies with a total of 1,417 participants were included in our study. The studies reported a low risk of bias. The mean age of the participants was 66.14 and more than 65% were males. Elevated CT-IGFBP-4 levels were associated with poor cardiovascular outcomes and increased mortality in severely ill patients. In contrast, there were no significant findings in the case of stable patients. Sandwich ELISA using lithium-heparin plasma provided a better detection limit of 0.15 ng/ml, low cross-reactivity (<2%), and generated linear results between 12 and 500 ng/ml.

Conclusion

CT-IGFBP-4 is an efficient biomarker for the prediction of MACE and mortality in patients with severe ischemic cardiovascular events.

Circulating insulin-like growth factor system adaptations in hibernating brown bears indicate increased tissue IGF availability

Brown bears conserve muscle and bone mass during 6 mo of inactive hibernation. The molecular mechanisms underlying hibernation physiology may have translational relevance for human therapeutics. We hypothesize that protective mechanisms involve increased tissue availability of insulin-like growth factors (IGFs). In subadult Scandinavian brown bears, we observed that mean plasma IGF-1 and IGF-2 levels during hibernation were reduced to 36 ± 10% and 56 ± 15%, respectively, compared with the active state (n = 12). Western ligand blotting identified IGF-binding protein (IGFBP)-3 as the major IGFBP in the active state, whereas IGFBP-2 was codominant during hibernation. Acid labile subunit (ALS) levels in hibernation were reduced to 41±16% compared with the active state (n = 6). Analysis of available grizzly bear RNA sequencing data revealed unaltered liver mRNA IGF-1, IGFBP-2, and IGFBP-3 levels, whereas ALS levels were significantly reduced during hibernation (n = 6). Reduced ALS synthesis and circulating levels during hibernation should prompt a shift from ternary IGF/IGFBP/ALS to smaller binary IGF/IGFBP complexes, thereby increasing IGF tissue availability. Indeed, size-exclusion chromatography of bear plasma demonstrated a shift to lower molecular weight IGF-containing complexes in the hibernating versus the active state. Furthermore, we note that the major IGF-2 mRNA isoform expressed in livers in both Scandinavian brown bears and grizzly bears was an alternative splice variant in which Ser29 is replaced with a tetrapeptide possessing a positively charged Arg residue. Homology modeling of the bear IGF-2/IGFBP-2 complex showed the tetrapeptide in proximity to the heparin-binding domain involved in bone-specific targeting of this complex. In conclusion, this study provides data which suggest that increased IGF tissue availability combined with tissue-specific targeting contribute to tissue preservation in hibernating bears.NEW & NOTEWORTHY Brown bears shift from circulating ternary IGF/IGFBP/ALS complexes in the active state to binary IGF/IGFBP complexes during hibernation, indicating increased tissue IGF-bioactivity. Furthermore, brown bears use a splice variant of IGF-2, suggesting increased bone-specific targeting of IGF anabolic signaling.

Reduced IGFBP-2 related immunoreactivity in human serum correlates with arterial stiffness in a healthy Chinese population

BACKGROUND

Circulating insulin-like growth factor binding protein 2 (IGFBP-2) is associated with metabolic changes in both physiological and pathological conditions. The aim of this study was to investigate the correlation between IGFBP-2 related immunoreactivity in serum and arterial stiffness in a healthy Chinese population.

METHODS

In this cross-sectional study, 360 healthy participants aged 37-87 years were recruited from 1500 and were divided into three groups according to serum IGFBP-2 related immunoreactivity (Tertile I, 25.437 ng/ml-120.870 ng/ml; Tertile II, 120.871 ng/ml-161.914 ng/ml; Tertile III, 161.915 ng/ml-321.636 ng/ml). Arterial stiffness was evaluated by measuring the brachial-ankle pulse wave velocity (baPWV), ankle-brachial index (ABI), and carotid intima-media thickness (cIMT). The association between IGFBP-2 related immunoreactivity and arterial stiffness was estimated by multiple stepwise regression.

RESULTS

Compared with the other two groups population, the individuals in Tertile I had significantly older age (62.66 ± 13.30 years, P < 0.01), lower level of triglyceride (1.08 ± 0.70 mmol/l, P < 0.01) and E/A (peak velocity of early filling and preak velocity of atrial filling ratio) (0.90 ± 0.33, P < 0.05). IGFBP-2 related immunoreactivity was inversely related with baPWV in the total population (r = -0.171, P < 0.01) and in Tertile I (r = -0.275, P < 0.01). After adjusting for age and the other confounders, no association was found between IGFBP-2 related immunoreactivity and baPWV in the total population. However, In Tertile I, reduced IGFBP-2 related immunoreactivity in serum was an independent risk factor of baPWV acceleration in three different adjustment models: Model 1 (no adjustment, P < 0.01), Model 2 (adjusted for age, P < 0.05), and Model 3 (adjusted for all variables, P < 0.05).

CONCLUSION

IGFBP-2 related immunoreactivity in serum is inversely associated with baPWV in a healthy Chinese population. This association did not change after adjustment for conventional risk factors for cardiovascular diseases in the subjects with the lowest IGFBP-2 related immunoreactivity. Consequently, reduction of IGFBP-2 related immunoreactivity may be a predictor of arterial stiffness. IGFBP-2 seems to be a potential intervention target in early atherosclerosis.

The Translation and Commercialisation of Biomarkers for Cardiovascular Disease—A Review

As a leading cause of mortality and morbidity worldwide, cardiovascular disease and its diagnosis, quantification, and stratification remain significant health issues. Increasingly, patients present with cardiovascular disease in the absence of known risk factors, suggesting the presence of yet unrecognized pathological processes and disease predispositions. Fortunately, a host of emerging cardiovascular biomarkers characterizing and quantifying ischaemic heart disease have shown great promise in both laboratory settings and clinical trials. These have demonstrated improved predictive value additional to widely accepted biomarkers as well as providing insight into molecular phenotypes beneath the broad umbrella of cardiovascular disease that may allow for further personalized treatment regimens. However, the process of translation into clinical practice – particularly navigating the legal and commercial landscape – poses a number of challenges. Practical and legal barriers to the biomarker translational pipeline must be further considered to develop strategies to bring novel biomarkers into the clinical sphere and apply these advances at the patient bedside. Here we review the progress of emerging biomarkers in the cardiovascular space, with particular focus on those relevant to the unmet needs in ischaemic heart disease.

Differential Diagnosis between Takotsubo Syndrome and Acute Coronary Syndrome—A Prospective Analysis of Novel Cardiovascular Biomarkers for a More Selective Triage

Introduction: Takotsubo syndrome (TTS) is clinically indistinguishable from an ACS. Despite the implementation of clinical scoring systems and novel biomarkers, coronary angiography currently remains necessary for differential diagnosis. Methods: 93 patients with chest pain and the suspicion of TTS were enrolled in two study centers. Fetuin-A, IGFBP-2, Galectin-3, and TNF α were determined in serum samples, collected within 24 h after the onset of symptoms. Serum levels of biomarkers were analyzed for the differential diagnostic value between TTS and ACS. Results: Compared to TTS, patients with ACS had significantly lower serum levels of Fetuin-A and IGFBP-2. The cut-off value of Fetuin-A for the identification of TTS compared to ACS was 55.74 μg/mL (sensitivity: 100.0%, specificity: 82.6%, PPV: 63.2%, NPV: 100.0%). An optimal cut-off value for IGFBP-2 for the differential diagnosis between TTS and ACS was determined as 171.77 ng/mL (sensitivity: 76.0%, specificity: 82.6%, PPV: 76.4%, NPV 72.7%). Conclusion: Fetuin-A and IGFBP-2 might facilitate the triage between TTS and ACS and could be therefore of great benefit for the guidance of treatment.

Dynamic personalized risk prediction in chronic heart failure patients: a longitudinal, clinical investigation of 92 biomarkers (Bio-SHiFT study)

The aim of our observational study was to derive a small set out of 92 repeatedly measured biomarkers with optimal predictive capacity for adverse clinical events in heart failure, which could be used for dynamic, individual risk assessment in clinical practice. In 250 chronic HFrEF (CHF) patients, we collected trimonthly blood samples during a median of 2.2 years. We selected 537 samples for repeated measurement of 92 biomarkers with the Cardiovascular Panel III (Olink Proteomics AB). We applied Least Absolute Shrinkage and Selection Operator (LASSO) penalization to select the optimal set of predictors of the primary endpoint (PE). The association between repeatedly measured levels of selected biomarkers and the PE was evaluated by multivariable joint models (mvJM) with stratified fivefold cross validation of the area under the curve (cvAUC). The PE occurred in 66(27%) patients. The optimal set of biomarkers selected by LASSO included 9 proteins: NT-proBNP, ST2, vWF, FABP4, IGFBP-1, PAI-1, PON-3, transferrin receptor protein-1, and chitotriosidase-1, that yielded a cvAUC of 0.88, outperforming the discriminative ability of models consisting of standard biomarkers (NT-proBNP, hs-TnT, eGFR clinically adjusted) − 0.82 and performing equally well as an extended literature-based set of acknowledged biomarkers (NT-proBNP, hs-TnT, hs-CRP, GDF-15, ST2, PAI-1, Galectin 3) − 0.88. Nine out of 92 serially measured circulating proteins provided a multivariable model for adverse clinical events in CHF patients with high discriminative ability. These proteins reflect wall stress, remodelling, endothelial dysfunction, iron deficiency, haemostasis/fibrinolysis and innate immunity activation. A panel containing these proteins could contribute to dynamic, personalized risk assessment.

Clinical Trial Registration: 10/05/2013 https://clinicaltrials.gov/ct2/show/NCT01851538?term=nCT01851538&draw=2&rank=1.

Insulin Growth Factor Phenotypes in Heart Failure with Preserved Ejection Fraction, an INSPIRE Registry and CATHGEN Study: IGF axis in HFpEF

BACKGROUND

The insulin like growth factor (IGF) axis emerged as an important pathway in heart failure with preserved ejection (HFpEF). We aimed to identify IGF phenotypes associated with HFpEF in the context high-dimensional proteomic profiling.

METHODS

From the Intermountain INSPIRE Registry, we identified 96 patients with HFpEF and matched controls. We performed targeted proteomics including IGF-1,2, IGF binding proteins (IGFBP) 1-7 and 111 other proteins (EMD Millipore and ELISA). We used partial least square discriminant analysis (PLS-DA) to identify a set of proteins associated with prevalent HFpEF, pulmonary hypertension (PH) and 5-year-all-cause mortality. K-mean clustering was used to identify IGF phenotypes.

RESULTS

Patients with HFpEF had a high prevalence of systemic hypertension (95%) and coronary artery disease (74%). Using PLS-DA, we identified a set of biomarkers including IGF1,2 and IGFBP-1,2,7 that provided a strong discrimination of HFPEF, PH and mortality with an AUC of 0.91, 0.77 and 0.83, respectively. Using K mean clustering, we identified three IGF phenotypes that were independently associated with all-cause 5-year mortality after adjustment for age, NT-proBNP and kidney disease (p=0.004). Multivariable analysis validated the prognostic value of IGFBP-1 and 2 in the CATHGEN biorepository.

CONCLUSION

IGF phenotypes were associated with PH and mortality in HFpEF.

Lactate Dehydrogenase B and Pyruvate Oxidation Pathway Associated With Carfilzomib-Related Cardiotoxicity in Multiple Myeloma Patients: Result of a Multi-Omics Integrative Analysis

Multiple myeloma (MM) is the second most frequent hematologic cancer in the United States. Carfilzomib (CFZ), an irreversible proteasome inhibitor being used to treat relapsed and refractory MM, has been associated with cardiotoxicity, including heart failure. We hypothesized that a multi-omics approach integrating data from different omics would provide insights into the mechanisms of CFZ-related cardiovascular adverse events (CVAEs). Plasma samples were collected from 13 MM patients treated with CFZ (including 7 with CVAEs and 6 with no CVAEs) at the University of Florida Health Cancer Center. These samples were evaluated in global metabolomic profiling, global proteomic profiling, and microRNA (miRNA) profiling. Integrative pathway analysis was performed to identify genes and pathways differentially expressed between patients with and without CVAEs. The proteomics analysis identified the up-regulation of lactate dehydrogenase B (LDHB) [fold change (FC) = 8.2, p = 0.01] in patients who experienced CVAEs. The metabolomics analysis identified lower plasma abundance of pyruvate (FC = 0.16, p = 0.0004) and higher abundance of lactate (FC = 2.4, p = 0.0001) in patients with CVAEs. Differential expression analysis of miRNAs profiling identified mir-146b to be up-regulatein (FC = 14, p = 0.046) in patients with CVAE. Pathway analysis suggested that the pyruvate fermentation to lactate pathway is associated with CFZ-CVAEs. In this pilot multi-omics integrative analysis, we observed the down-regulation of pyruvate and up-regulation of LDHB among patients who experienced CVAEs, suggesting the importance of the pyruvate oxidation pathway associated with mitochondrial dysfunction. Validation and further investigation in a larger independent cohort are warranted to better understand the mechanisms of CFZ-CVAEs.

Diagnostic and Prognostic Utilities of Insulin-Like Growth Factor Binding Protein-7 in Patients With Dyspnea

OBJECTIVES

This study examined whether insulin-like growth factor binding protein-7 (IGFBP7) would aid in the diagnosis and prognosis of acute heart failure (HF) beyond N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration.

BACKGROUND

IGFBP7 is associated with impaired ventricular relaxation and worse prognosis.

METHODS

The ICON-RELOADED (International Collaborative of NT-proBNP-Re-evaluation of Acute Diagnostic Cut-Offs in the Emergency Department) study was a prospective, multicenter clinical trial that enrolled subjects presenting with dyspnea. Six-month prognosis for death or repeat hospitalization was obtained.

RESULTS

Among 1,449 patients, 274 (18.9%) were diagnosed with acute HF. Those with IGFBP7 concentrations in the highest quartile were older, male, had hypertension and HF, had lower estimated glomerular filtration rate (eGFR) and lowest ejection fraction (41 ± 20%; all p < 0.001). Independent predictors of IGFBP7 were age, male sex, history of diabetes, history of HF, and eGFR. Median concentrations of NT-proBNP (2,844 ng/ml vs. 99 ng/ml) and IGFBP7 (146.1 ng/ml vs. 86.1 ng/ml) were higher in those with acute HF (both; p < 0.001). Addition of IGFBP7 to NT-proBNP concentrations improved discrimination, therefore increasing the area under the receiver operating curve for diagnosis of acute HF (from 0.91 to 0.94; p < 0.001 for differences). Addition of IGFBP7 to a complete model of independent predictors of acute HF improved model calibration. IGFBP7 significantly reclassified acute HF diagnosis beyond NT-proBNP (net reclassification index: +0.25). Higher log₂-IGFBP7 concentrations in patients with acute HF predicted death or rehospitalization at 6 months (hazard ratio: 1.84 per log₂-SD; 95% confidence interval: 1.30 to 2.61; p = 0.001). In Kaplan-Meier analyses, supramedian concentrations of IGFBP7 were associated with shorter event-free survival (log-rank: p < 0.001).

CONCLUSIONS

Among patients with acute dyspnea, concentrations of IGFBP7 add to NT-proBNP for diagnosis of acute HF and provide added prognostic utility for short-term risk.

Similar dietary regulation of IGF-1- and IGF-binding proteins by animal and plant protein in subjects with type 2 diabetes

Increased animal but not plant protein intake has been associated with increased mortality in epidemiological studies in humans and with reduced lifespan in animal species. Protein intake increases the activity of the IGF-1 system which may provide a link to reduced lifespan. We, therefore, compared the effects of animal versus plant protein intake on circulating levels of IGF-1 and the IGF-binding proteins (IGFBP)-1 and IGFBP-2 over a 6-week period. Thirty seven participants with type 2 diabetes consumed isocaloric diets composed of either 30% energy (EN) animal or plant protein, 30% EN fat and 40% EN carbohydrates for 6 weeks. The participants were clinically phenotyped before and at the end of the study. Both diets induced similar and significant increases of IGF-1 which was unaffected by the different amino acid compositions of plant and animal protein. Despite improvements of insulin sensitivity and major reductions of liver fat, IGFBP2 decreased with both diets while IGFBP-1 was not altered. We conclude that animal and plant protein similarly increase IGF-1 bioavailability while improving metabolic parameters and may be regarded as equivalent in this regard.

Elevated plasma endocan and BOC in heart failure patients decrease after heart transplantation in association with improved hemodynamics

BACKGROUND

The prevalence of heart failure (HF) is rising with ageing population and constitutes a major health problem globally. A common complication of HF is pulmonary hypertension (PH) which negatively impacts survival. A pathophysiological association between HF and PH with tumorigenic processes has been suggested. We aimed to identify the plasma levels of, and the association between tumour-related proteins and hemodynamic improvements in patients with HF and PH due to left heart disease (LHD) before and 1-year after heart transplantation (HT).

METHODS

Forty-eight tumour-related proteins were measured with proximity extension assay in plasma from 20 controls and 26 HF patients before and 1-year after HT. Patients' hemodynamics were measured with right heart catheterization.

RESULTS

Out of 48 proteins, specifically, plasma levels of endocan and brother of CDO (BOC) were elevated in end-stage HF patients compared to controls (p < 0.001), but decreased after HT (p < 0.01), towards controls' levels. The decrease of endocan levels after HT correlated with improved mean pulmonary arterial pressure (rs = 0.80, p < 0.0001), pulmonary arterial wedge pressure (rs = 0.63, p = 0.0012), and pulmonary vascular resistance (rs = 0.70, p < 0.001). The decrease and normalization of BOC after HT correlated with decreased mean right atrial pressure (rs = 0.61 p = 0.0015) and NT-proBNP (rs = 0.57, p = 0.0022), as well as increased cardiac index (rs = - 0.51, p = 0.0086) and left-ventricular stroke work index (rs = - 0.57, p = 0.0039).

CONCLUSION

Our results suggest that (i) plasma endocan in HF may reflect the state of pulmonary vascular congestion and PH-LHD, whereas (ii) plasma BOC may reflect the cardiac function and the hemodynamic overload in HF. The exact role of these proteins and their clinical applicability as biomarkers in HF and PH-LHD ought to be investigated in larger cohorts.

Insulin-like growth factor binding protein-2: a new circulating indicator of pulmonary arterial hypertension severity and survival

BACKGROUND

Pulmonary arterial hypertension (PAH) is a fatal disease that results from cardio-pulmonary dysfunction with the pathology largely unknown. Insulin-like growth factor binding protein 2 (IGFBP2) is an important member of the insulin-like growth factor family, with evidence suggesting elevation in PAH patients. We investigated the diagnostic and prognostic value of serum IGFBP2 in PAH to determine if it could discriminate PAH from healthy controls and if it was associated with disease severity and survival.

METHODS

Serum IGFBP2 levels, as well as IGF1/2 levels, were measured in two independent PAH cohorts, the Johns Hopkins Pulmonary Hypertension program (JHPH, N = 127), NHLBI PAHBiobank (PAHB, N = 203), and a healthy control cohort (N = 128). The protein levels in lung tissues were determined by western blot. The IGFBP2 mRNA expression levels in pulmonary artery smooth muscle cells (PASMC) and endothelial cells (PAEC) were assessed by RNA-seq, secreted protein levels by ELISA. Association of biomarkers with clinical variables was evaluated using adjusted linear or logistic regression and Kaplan-Meier analysis.

RESULTS

In both PAH cohorts, serum IGFBP2 levels were significantly elevated (p < 0.0001) compared to controls and discriminated PAH from controls with an AUC of 0.76 (p < 0.0001). A higher IGFBP2 level was associated with a shorter 6-min walk distance (6MWD) in both cohorts after adjustment for age and sex (coefficient - 50.235 and - 57.336 respectively). Cox multivariable analysis demonstrated that higher serum IGFBP2 was a significant independent predictor of mortality in PAHB cohort only (HR, 3.92; 95% CI, 1.37-11.21). IGF1 levels were significantly increased only in the PAHB cohort; however, neither IGF1 nor IGF2 had equivalent levels of associations with clinical variables compared with IGFBP2. Western blotting shown that IGFBP2 protein was significantly increased in the PAH vs control lung tissues. Finally, IGFBP2 mRNA expression and secreted protein levels were significantly higher in PASMC than in PAEC.

CONCLUSIONS

IGFBP2 protein expression was increased in the PAH lung, and secreted by PASMC. Elevated circulating IGFBP2 was associated with PAH severity and mortality and is a potentially valuable prognostic marker in PAH.

Overlap of Peak Growth Activity and Peak IGF-1 to IGFBP Ratio: Delayed Increase of IGFBPs versus IGF-1 in Serum as a Mechanism to Speed up and down Postnatal Weight Gain in Mice

Forced expression of insulin-like growth factor binding proteins (IGFBPs) in transgenic mice has clearly revealed inhibitory effects on somatic growth. However, by this approach, it cannot be solved if or how IGFBPs rule insulin-like growth factor (IGF)-dependent growth under normal conditions. In order to address this question, we have used growth-selected mouse models (obese and lean) and studied IGF-1 and IGFBPs in serum with respect to longitudinal growth activity in males and females compared with unselected controls. In mice of both genders, body weights were recorded and daily weight gains were calculated. Between 2 and 54 weeks of age, serum IGF-1 was determined by ELISA and intact IGFBP-2, -3 and -4 were quantified by Western ligand blotting. The molar ratio of IGF-1 to the sum of IGFBP-2 to -4 was calculated for all groups and plotted against the daily weight gain curve. Growth-selected mice are characterized by higher daily weight gains and extended periods of elevated growth activity if compared to matched unselected controls. Therefore, adult mice from the obese and lean groups can achieve more than twofold increased body weight in both genders (p < 0.001). Between 2 and 11 weeks of age, in obese and lean mice of both genders, serum IGF-1 concentrations are increased more prominently if compared to unselected controls (p < 0.001). Instead, substantial decreases of IGFBPs, particularly of IGFBP-2, are observed in males and females of all groups at the age of 2 to 4 weeks (p < 0.001). Due to the strong increase of IGF-1 but not of IGFBPs between two and four weeks of age, the ratio of IGF-1 to IGFBP-2 to -4 in serum significantly increased in all groups and genders (p < 0.05). Notably, the IGF-1 to IGFBP ratio was higher in male and female obese mice if compared to unselected controls (p < 0.05).

Endothelial cell-derived extracellular vesicles alter vascular smooth muscle cell phenotype through high-mobility group box proteins

The vascular endothelium and smooth muscle form adjacent cellular layers that comprise part of the vascular wall. Each cell type can regulate the other’s structure and function through a variety of paracrine effectors. Extracellular vesicles (EVs) are released from and transit between cells constituting a novel means of cell–cell communication. Here, we characterized the proteome of EVs released from each vascular cell type and examined the extent to which these vesicles participate in endothelial-vascular smooth muscle cell (VSMC) communication. EVs were collected by ultracentrifugation from media of rat aortic endothelial and smooth muscle cells cultured under serum-free conditions. Vesicle morphology, size and concentration were evaluated by transmission electron microscopy and nanoparticle tracking analysis. Western blot as well as shot gun proteomic analyses revealed sets of proteins common to both endothelial- and smooth muscle-derived EVs as well as proteins unique to each vascular cell type. Functionally, endothelial-derived EVs stimulated vascular cell adhesion molecule-1 (VCAM-1) expression and enhanced leukocyte adhesion in VSMCs while smooth muscle EVs did not elicit similar effects in endothelial cells (ECs). EVs from ECs also induced protein synthesis and senescence in VSMCs. Proteomic analysis of VSMCs following exposure to EC-derived EVs revealed upregulation of several proteins including pro-inflammatory molecules, high-mobility group box (HMGB) 1 and HMGB2. Pharmacological blockade HMGB1 and HMGB2 and siRNA depletion of HMGB1 in smooth muscle cells attenuated VCAM-1 expression and leukocyte adhesion induced by EC EVs. These data suggest that EC-derived EVs can enhance signalling pathways which influence smooth muscle cell phenotype.

Novel Biomarkers in Patients with Chronic Kidney Disease: An Analysis of Patients Enrolled in the GCKD-Study

Background: Chronic kidney disease (CKD) and cardiovascular diseases (CVD) often occur concomitantly, and CKD is a major risk factor for cardiovascular mortality. Since some of the most commonly used biomarkers in CVD are permanently elevated in patients with CKD, novel biomarkers are warranted for clinical practice. Methods: Plasma concentrations of five cardiovascular biomarkers (soluble suppression of tumorigenicity (sST2), growth differentiation factor 15 (GDF-15), heart-type fatty acid-binding protein (H-FABP), insulin-like growth factor-binding protein 2 (IGF-BP2), and soluble urokinase plasminogen activator receptor) were analyzed by means of enzyme-linked immunosorbent assay (ELISA) in 219 patients with CKD enrolled in the German Chronic Kidney Disease (GCKD) study. Results: Except for sST2, all of the investigated biomarkers were significantly elevated in patients with CKD (2.0- to 4.4-fold increase in advanced CKD (estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m² body surface area (BSA)) and showed a significant inverse correlation with eGFR. Moreover, all but H-FABP and sST2 were additionally elevated in patients with micro- and macro-albuminuria. Conclusions: Based on our findings, sST2 appears to be the biomarker whose diagnostic performance is least affected by decreased renal function, thus suggesting potential viability in the management of patients with CVD and concomitant CKD. The predictive potential of sST2 remains to be proven in endpoint studies.

Cardiorenal interaction and heart failure outcomes. A role for insulin-like growth factor binding protein 2?

INTRODUCTION AND OBJECTIVES

Preliminary results suggest that high circulating insulin-like growth factor binding protein 2 (IGFBP2) levels are associated with mortality risk in heart failure (HF) patients. As IGFBP2 levels are increased in patients with chronic kidney disease (CKD), which is associated with a higher mortality risk in HF patients, we examined whether IGFBP2 is associated with CKD in HF patients, and whether CKD modifies the prognostic value of this protein in HF patients.

METHODS

HF patients (n=686, mean age 66.6 years, 32.7% women) were enrolled and followed up for a median of 3.5 (min-max range: 0.1-6) years. Patients were classified as having CKD with decreased estimated glomerular filtration rate (eGFR <60mL/min/1.73 m²) or as having CKD with nondecreased eGFR (≥ 60mL/min/1.73 m²). Serum IGFBP2 was detected by ELISA.

RESULTS

IGFBP2 was increased (P <.001) in CKD patients with decreased eGFR (n=290, 42.3%) compared with patients with nondecreased eGFR. IGFBP2 was directly associated with NT-proBNP (P <.001) and inversely associated with eGFR (P <.001), with both associations being independent of confounding factors. IGFBP2 was directly and independently associated with cardiovascular and all-cause death (P <.001) in the whole group of patients, but showed a stronger association with cardiovascular death in CKD patients with decreased eGFR (P for interaction <.05), improving risk prediction in these patients over clinically relevant risk factors.

CONCLUSIONS

Serum IGFBP2 is associated with impaired renal function and prognosticates cardiovascular death in patients with HF and CKD with decreased eGFR. Thus, there is an effect modification of CKD on circulating IGFBP2 and on its association with cardiovascular mortality in HF patients.

Pregnancy-Associated Plasma Protein-A2 Is Associated With Mortality in Patients With Lung Cancer

Pregnancy-associated plasma protein-A (PAPP-A) and its homolog PAPP-A2 are enzymes that modulate the availability and mitogenic activity of insulin-like growth factor-I (IGF-I). PAPP-A has been implicated in numerous cancers but reports on PAPP-A2 in malignancy are non-existent. In a prospective observational study of 689 patients under suspicion of lung cancer, we examined levels of PAPP-A and PAPP-A2 and their relationship with mortality. Serum PAPP-A and PAPP-A2 concentrations were determined in pre-diagnostic blood samples using ELISA, and immunohistochemical staining of PAPP-A and PAPP-A2 was performed in malignant tissue from five operable patients. A total of 144 patients were diagnosed with lung cancer, whereas the diagnosis was rejected in 545 subjects, who served as a control group. PAPP-A2 concentrations were higher in patients with lung cancer [median (IQR): 0.33 (0.21-0.56) ng/mL] than in controls [0.27 (0.17-0.39) ng/mL], p < 0.001, whereas PAPP-A levels did not differ. Presence of PAPP-A and PAPP-A2 were confirmed in tumor specimens, and staining occurred in a heterogeneous pattern. Patients were observed for a median (range) of 7 (6; 8) years, during which 114 patients (79.2%) died. Patient mortality differed according to PAPP-A2 tertile (p < 0.001). PAPP-A2 was associated with mortality with an unadjusted hazard ratio (95% CI) per doubling in protein concentration of 1.30 (1.12; 1.53), p = 0.001. In a multivariable model adjusted for age, sex, and BMI, PAPP-A2 remained predictive of the endpoint with a hazard ratio per doubling in protein concentration of 1.25 (1.05; 1.48), p = 0.013. Collectively, PAPP-A2, but not PAPP-A, is elevated in patients with lung cancer and associated with mortality. This novel role of PAPP-A2 in cancer warrants further functional studies as well as validation in external cohorts.

Differential expression of novel MicroRNAs from developing fetal heart of Gallus gallus domesticus implies a role in cardiac development

Heart development is a complex process regulated by multi-layered genetic as well epigenetic regulators many of which are still unknown. Besides their critical role during cardiac development, these molecular regulators emerge as key modulators of cardiovascular pathologies, where fetal cardiac genes' re-expression is witnessed. MicroRNAs have recently emerged as a crucial part of signalling cascade in both development and diseases. We aimed to identify, validate, and perform functional annotation of putative novel miRNAs using chicken as a cardiac development model system. Novel miRNAs were obtained through deep sequencing of small RNAs extracted from chicken embryonic cardiac tissue of different developmental stages. After filtering out real pre-miRNAs, their expression analysis, potential target gene's prediction and functional annotations were performed. Expression analysis revealed that miRNAs were differentially expressed during different developmental stages of chicken heart. The expression of selected putative novel miRNAs was further validated by real-time PCR. Our analysis indicated the presence of novel cardiac miRNAs that might be regulating critical cardiac development events such as cardiac cell growth, differentiation, cardiac action potential generation and signal transduction.

The IGF system in patients with inflammatory bowel disease treated with prednisolone or infliximab: potential role of the stanniocalcin-2 / PAPP-A / IGFBP-4 axis

Background

Patients with inflammatory bowel disease (IBD) present with reduced serum insulin-like growth factor I (IGF-I). Anti-inflammatory treatment with prednisolone or infliximab ameliorates symptoms and increases circulating IGF-I, but prednisolone induces catabolism, whereas infliximab may promote protein synthesis. Recently, stanniocalcin-2 (STC2) was discovered as a novel inhibitor of the enzyme pregnancy-associated plasma protein-A (PAPP-A), which modulates IGF-I activity. PAPP-A can cleave IGF binding protein-4 (IGFBP-4), upon which IGF-I is liberated. We hypothesized that prednisolone and infliximab exert different effects on levels of STC2, PAPP-A, and IGFBP-4, thereby explaining the distinct metabolic effects of prednisolone and infliximab.

Methods

Thirty-eight patients with active IBD treated with either prednisolone (n = 17) or infliximab (n = 21) were examined before and after 7 days of treatment. Circulating levels of IGF-I, IGF-II, IGFBP-3, PAPP-A, and STC2 were measured by immunoassays. Intact IGFBP-4 and two IGFBP-4 fragments were determined by a novel immunoassay. Bioactive IGF was assessed by cell-based IGF receptor activation assay. Concentrations of IGFBP-4, PAPP-A, and STC2 on day 0 and 7 were compared to healthy control subjects.

Results

Following seven days of prednisolone treatment, total and bioactive IGF-I were increased (p < 0.001 and p < 0.05, respectively). Upon infliximab treatment, total IGF-I levels were augmented (p < 0.05), yet IGF bioactivity remained unaltered. Intact IGFBP-4 and the two IGFBP-4 fragments generated upon cleavage by PAPP-A were all decreased following treatment with either prednisolone or infliximab (all p < 0.05). PAPP-A levels were only increased by infliximab (p = 0.005), whereas the inhibitor STC2 did not respond to any of the treatments.

Conclusion

IGF-I and IGFBP-4 concentrations were markedly altered in patients with IBD and near-normalized with disease remission following treatment with prednisolone or infliximab. Thus, IGFBP-4 may modulate IGF bioavailability in IBD. The effect of immunosuppression did not appear to extend beyond the regulation of IGF and IGFBP-4, as neither PAPP-A nor STC2 were discernibly affected.

Trial registration

ClinicalTrials.gov: NCT00955123. Date of registration: August 7, 2009 (retrospectively registered).

Plausible Links Between Metabolic Networks, Stem Cells, and Longevity

Aging is an inevitable consequence of life, and all multicellular organisms undergo a decline in tissue and organ functions as they age. Several well-known risk factors, such as obesity, diabetes, and lack of physical activity that lead to the cardiovascular system, decline and impede the function of vital organs, ultimately limit overall life span. Over recent years, aging research has experienced an unparalleled growth, particularly with the discovery and recognition of genetic pathways and biochemical processes that control to some extent the rate of aging.In this chapter, we focus on several aspects of stem cell biology and aging, beginning with major cellular hallmarks of aging, endocrine regulation of aging and its impact on stem cell compartment, and mechanisms of increased longevity. We then discuss the role of epigenetic modifications associated with aging and provide an overview on a most recent search of antiaging modalities.