Relaxin family peptide receptors (RXFP, nomenclature as agreed by the NC-IUPHAR Subcommittee on Relaxin family peptide receptors [23, 125]) may be divided into two pairs, RXFP1/2 and RXFP3/4. Endogenous agonists at these receptors are heterodimeric peptide hormones structurally related to insulin: relaxin-1, relaxin, relaxin-3 (also known as INSL7), insulin-like peptide 3 (INSL3) and INSL5. Species homologues of relaxin have distinct pharmacology and relaxin interacts with RXFP1, RXFP2 and RXFP3, whereas mouse and rat relaxin selectively bind to and activate RXFP1 [268]. relaxin-3 is the ligand for RXFP3 but it also binds to RXFP1 and RXFP4 and has differential affinity for RXFP2 between species [267]. INSL5 is the ligand for RXFP4 but is a weak antagonist of RXFP3. relaxin and INSL3 have multiple complex binding interactions with RXFP1 [275] and RXFP2 [138], which together with the N-terminal linker and LDLa module drive receptor activation by an unknown mechanism [270, 89]. INSL5 and relaxin-3 interact with their receptors using distinct residues in their B-chains for binding, and activation, respectively [55, 329, 158, 56].

Relaxin-2 (RLX), a critical hormone in pregnancy, has been investigated as a therapy for heart failure. In most studies, the peptide was delivered continuously, subcutaneously for 2 weeks in animals or intravenously for 2days in human subjects, for stable circulating [RLX]. However, pulsatile hormone levels may better uncover the normal physiology. This premise was tested by subcutaneously injecting Sprague Dawley rats (250 g, N = 2 males, 2 females/ group) with human RLX (0, 30, 100, or 500 mu g/kg), every 12 h for 1 day, then measuring changes in Nav1.5, connexin43, and beta-catenin, 24 h later. Pulsatile RLX was measured by taking serial blood draws, post-injection. After an injection, RLX reached a peak in similar to 60 min, fell to 50 % in 5-6 h; injections of 0, 30, 100 or 500 mu g/kg yielded peak levels of 0, 11.26 +/- 3.52, 58.33 +/- 16.10, and 209.42 +/- 29.04 ng/ml and residual levels after 24-hrs of 0, 4.9, 45.1 and 156 pg/ml, respectively. The 30 mu g/kg injections had no effect and 100 mu g/kg injections increased Nav1.5 (25 %), Cx43 (30 %) and beta-catenin (90 %). The 500 mu g/kg injections also increased Nav1.5 and Cx43 but were less effective at upregulating beta-catenin (up by 25 % vs. 90 %). Periodic injections of 100 mu g/kg were highly effective at increasing the expression of Nav1.5 and Cx43 which are key determinants of conduction velocity in the heart and the suppression of arrhythmias. Periodic RLX is effective at eliciting changes in cardiac protein expression and may be a better strategy for its longer -term delivery in the clinical setting.

IMPORTANCE: Postoperative delirium (POD) is a multietiological condition and affects 20% of older surgical patients. It is associated with poor clinical outcome and increased mortality. OBJECTIVE: We aimed to develop and validate a risk prediction algorithm for POD based on a multimodal biomarker database exploiting preoperative data (predisposing factors) and procedural factors as well as perioperative molecular changes associated with POD (precipitating factors). DESIGN: BioCog is a prospective cohort study conducted from November 2014 to April 2017. Patients were followed up for seven postoperative days after surgery for POD. Gradient-boosted trees (GBT) with nested cross-validation was used for POD prediction. SETTING: Patients aged ≥65 years were enrolled at the anesthesiologic departments of two tertiary care centers. EXPOSURE: All patients underwent surgery with an expected duration of at least 60min. Clinical, neuropsychological, neuroimaging data and blood were collected and clinically well established as well as non-established biomarkers (e.g., gene expression profiling) were measured pre- and postoperatively. MAIN OUTCOME: POD according to DSM 5 until the seventh postoperative day RESULTS: 184 of 929 (20%) patients experienced POD. A GBT algorithm using both preoperative data, characteristics of the intervention and postoperative changes in laboratory parameters achieved the highest area under the curve (0.83, [0.79; 0.86]) with a Brier score of 0.12 (0.12; 0.13). CONCLUSIONS AND RELEVANCE: Models combining predisposing factors with precipitating factors predict POD best. Non-routine laboratory data provide useful information for POD risk prediction, providing relevant results for future studies on the molecular factors of POD. In addition, possibly relevant molecular mechanisms contributing to the development of POD were identified, mostly indicating a dysregulated postoperative immune response. This study constitutes the basis for future hypothesis-driven analyses or implementation of prediction expert system for clinical practice. ### Competing Interest Statement Georg Winterer is currently licensing a Class IIa medical device (web-based software tool for risk prediction of POD and POCD in clinical practice). Dr. Winterer is CEO of PharmaImage Biomarker Solutions GmbH Berlin (Germany) and President of its subsidiary Pharmaimage Biomarkers Incl. (Cambridge, MA, USA). Dr. Spies, Dr. Winterer, Dr. Boraschi, Dr. Dschietzig, Dr. Kuehn, Dr. Nuernberg, Dr. Pischon, Dr. Pietzsch, Dr. Slooter, Dr. Stamatakis, Dr. Weber, report grants from the European Commission during the conduct of the study. Dr. Winterer reports grants from the Deutsche Forschungsgemeinschaft (DFG)/German Research Society and from the German Ministry of Health. Dr. Spies reports grants from DFG/German Research Society, Einstein Foundation Berlin, Deutsches Zentrum fuer Luft- und Raumfahrt e.V. (DLR)/German Aerospace Center, Projekttraeger im DLR/Project Management Agency, Gemeinsamer Bundesausschuss (GBA)/Federal Joint Committee, inneruniversity grants, Stifterverband/Non-Profit Society Promoting Science and Education, European Society of Anesthesiology and Intensive Care, BMWI - Federal Ministry of Economic Affairs and Climate Action, Dr. F. Koehler Chemie GmbH, Sintetica GmbH, Max-Planck-Gesellschaft zur Foerderung der Wissenschaft e.V., Metronic, BMBF - Federal Ministry of Education and Research, Robert Koch Institute and payments by Georg Thieme Verlag, board activity for Prothor, Takeda Pharmaceutical Company Ltd., Lynx Health Science GmbH, AWMF (Association of the Scientific Medical Societies in Germany), DFG, Deutsche Akademie der Naturforscher Leopoldina e.V. (German National Academy of Sciences Leopoldina), Berliner Medizinische Gesellschaft, European Society of Intensive Care Medicine (ESICM), European Society of Anaesthesiology and Intensive Care (ESAIC), Deutsche Gesellschaft fuer Anaesthesiologie und Intensivmedizin (DGAI)/German Society of Anaesthesiology and Intensive Care Medicine, German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI) as well as patents 15753 627.7, PCT/EP 2015/067731, 3 174 588, 10 2014 215 211.9, 10 2018 114 364.8, 10 2018 110 275.5, 50 2015 010 534.8, 50 2015 010 347.7, 10 2014 215 212.7. Gunnar Lachmann and Maria Heinrich report grants from the BIH Charite Clinician Scientist Program during conduct of the study. Dr. Dschietzig reports personal fees from Immundiagnostik AG during the conduct of the study. Dr. Lammers-Lietz and Anton Wiehe report personal fees from Pharmaimage Biomarker Solutions GmbH during the conduct of the study. Dr. Lachmann reports personal fees from Sobi, the University of Zurich and Thieme outside the submitted work. Dr. Wolf receives fees from the Kompetenz-Centrum Qualitaetssicherung. Dr. Stamatakis reports funding from Stephen Erskine Fellowship from Queens' College of the University of Cambridge, UK outside the BioCog study. Dr. Bresser reports funding from Alzheimer Nederland outside of the study. Dr. Gallinat received funding from the German Research Foundation (DFG), Federal Ministry of Education and Research (BMBF) and received payment for five lectures and presentations with about 1.500 euro per presentation sponsored by Lundbeck, Janssen-Cilag and Boehringer. Dr. Heilmann-Heimbach receives personal fees from Life&Brain GmbH. None of the other authors have a conflict of interest to declare. ### Funding Statement The research leading to these results has received funding from the European Union Seventh Framework Program [FP7/2007-2013] under grant agreement no. 602461. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committees of the Charite-Universitaetsmedizin Berlin, Germany, (EA2/092/14) and University Medical Center Utrecht (UMC), Utrecht University, Netherlands, (14-469) gave ethical approval of this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Due to the protection of intellectual property, machine learning algorithms will not be made publicly available, but can be obtained from Dr. Winterer (georg.winterer@pi-pharmaimage.com) after signing a confidentiality agreement. Participant data may be made available upon request following publication to researchers who provide a methodologically sound proposal in accordance with applicable legal and regulatory restrictions. Proposals for data analysis must be directed to both claudia.spies@charite.de and georg.winterer@pi-pharmaimage.com. To gain access, requesting researchers will need to sign a data access agreement. Analyses will be limited to those approved in appropriate ethics and governance arrangements. All study documents which do not identify individuals (e.g. study protocol, informed consent form) will be freely available on request.

ObjectiveIn humans, haptoglobin (Hp) exists in two allelic forms, Hp1 and Hp2, that differ significantly in their ability to protect the organism from oxidative stress. It has been proposed that in patients with diabetes mellitus carriers of the Hp2-2 genotype may benefit from vitamin E supplementation. Aim of our study was to investigate if there is evidence regarding a potential interaction between the Hp polymorphism and vitamin E with regard to mortality in individuals at medium-to-high cardiovascular risk with and without diabetes mellitus.Research design and methodsData from 3176 participants of the Ludwigshafen Risk and Cardiovascular Health study, a monocentric hospital-based study of patients referred for coronary angiography, were analysed using Cox proportional hazard regression.ResultsParticipants with the Hp2-2 genotype demonstrated significantly lower Hp levels, while carriers of at least one Hp-2 allele displayed elevated levels of the inflammatory markers high-sensitive C reactive protein and serum amyloid A. No notable differences in comorbidities were observed among the various HP genotype groups. While the HP genotype showed no direct association with mortality, a borderline significant correlation between α-tocopherol plasma concentration and overall mortality was noted. An interaction between vitamin E status and the HP genotype regarding mortality risk was evident, particularly among patients with diabetes mellitus, with a p value of 0.021 for the interaction term. In restricted cubic splice analysis, patients with diabetes mellitus who are carriers of the Hp2-2 genotype seem to benefit from higher γ-tocopherol concentrations whereas for the other genotype groups there was a direct association with mortality risk.ConclusionParticularly in patients with diabetes mellitus we could show a significant interaction of γ-tocopherol plasma concentration and HP genotype. Carriers of the Hp2-2 genotype seemed to benefit from higher plasma concentrations of γ-tocopherol. Further research is warranted to elucidate the underlying mechanisms and potential therapeutic implications in cardiovascular disease management.

The hormone relaxin-2 has emerged as a promising player in regulating the physiology of the cardiovascular system. Through binding to the relaxin family peptide receptor 1 (RXFP1), this hormone elicits multiple physiological responses including vasodilation induction, reduction of inflammation and oxidative stress, and angiogenesis stimulation. The role of relaxin-2, or its recombinant human form known as serelaxin, has been investigated in preclinical and clinical studies as a potential therapy for cardiovascular diseases, especially heart failure, whose current therapy is still unoptimized. However, evidence from past clinical trials has been inconsistent and further research is needed to fully understand the potential applications of relaxin-2. This review provides an overview of serelaxin use in clinical trials and discusses future directions in the development of relaxin-2 mimetics, which may offer new therapeutic options for patients with heart failure.

Relaxin family peptide receptors (RXFP, nomenclature as agreed by the NC-IUPHAR Subcommittee on Relaxin family peptide receptors [23, 119]) may be divided into two pairs, RXFP1/2 and RXFP3/4. Endogenous agonists at these receptors are heterodimeric peptide hormones structurally related to insulin: relaxin-1, relaxin, relaxin-3 (also known as INSL7), insulin-like peptide 3 (INSL3) and INSL5. Species homologues of relaxin have distinct pharmacology and relaxin interacts with RXFP1, RXFP2 and RXFP3, whereas mouse and rat relaxin selectively bind to and activate RXFP1 [260]. relaxin-3 is the ligand for RXFP3 but it also binds to RXFP1 and RXFP4 and has differential affinity for RXFP2 between species [259]. INSL5 is the ligand for RXFP4 but is a weak antagonist of RXFP3. relaxin and INSL3 have multiple complex binding interactions with RXFP1 [267] and RXFP2 [132] which direct the N-terminal LDLa modules of the receptors together with a linker domain to act as a tethered ligand to direct receptor signaling [262]. INSL5 and relaxin-3 interact with their receptors using distinct residues in their B-chains for binding, and activation, respectively [321, 152].

Aim To assess bone status expressed as hip bone mineral density (BMD) in men with heart failure (HF).Methods and results A total of 141 male patients with HF underwent dual energy X-ray absorptiometry to assess their BMD. We analysed markers of bone metabolism. Patients were classified as lower versus higher BMD according to the median hip BMD (median = 1.162 g/cm(2)). Survival was assessed over 8 years of follow-up. Patients with lower BMD were older (71 +/- 10 vs. 66 +/- 9 years, p = 0.004), more likely to be sarcopenic (37% vs. 7%, p < 0.001) and to have lower peak oxygen consumption (absolute peak VO2 1373 +/- 480 vs. 1676 +/- 447 ml/min, p < 0.001), had higher osteoprotegerin and osteocalcin levels (both p < 0.05) compared to patients with higher BMD. Among 47 patients with repeated BMD assessments, a significant reduction in BMD was noted over 30 months of follow-up. In multivariate logistic regression analysis, serum osteocalcin remained independently related with lower BMD (odds ratio [OR] 1.738, 95% confidence interval [CI] 1.136-2.660, p = 0.011). Hip BMD and serum osteoprotegerin were independent predictors of impaired survival on Cox proportional hazard analysis (hazard ratio [HR] 0.069, 95% CI 0.011-0.444, p = 0.005, and HR 0.638, 95% CI 0.472-0.864, p = 0.004, respectively).Conclusions Patients with HF lose BMD over time. Markers of bone turnover can help in identifying patients at risk with osteocalcin being an independent marker of lower hip BMD and osteoprotegerin an independent predictor of death. HF patients with increased osteocalcin and osteoprotegerin may benefit from BMD assessment as manifest osteoporosis seems to be too late for clinically meaningful intervention in HF.

Objective. Ischemia-reperfusion injury (IRI) is inevitable after kidney transplantation (KT), impairing outcomes. Relaxin-2 (RLX) is a promising insulin-related peptide hormone that protects against renal IRI in rodents, although large animal models are needed before RLX can be tested in a human setting. Methods. In this blinded, randomized, and placebo-controlled experimental study kidneys from 19 donor pigs were retrieved after perfusion with Custodiol® ± RLX (5 or 20 nmol/L) and underwent static cold storage (SCS) for 24 and 48 h, respectively. Subsequently, KT was performed after unilateral right nephrectomy. Study outcomes included markers for kidney function, oxidative stress, lipid peroxidation, and endothelial cell damage. PCR analysis for oxidative stress and apoptosis-related gene panels as well as immunohistochemistry were performed. Results. RLX upregulated SOD2 and NFKB expression to 135% (p = 0.042) and 125% (p = 0.019), respectively, while RIPK1 expression was downregulated to 82% (p = 0.016) of corresponding controls. Further RLX significantly downregulated RIPK1 and MLKL expression and decreased the number of Caspase 3- and MPO-positive cells in grafts after SCS. Conclusions. RLX supplemented Custodiol® significantly decreased IRI via both antioxidant and anti-apoptotic mechanisms. Clinical trials are warranted to implement synthetic human RLX as a novel additive to preservation solutions against IRI.

Relaxin family peptide receptors (RXFP, nomenclature as agreed by the NC-IUPHAR Subcommittee on Relaxin family peptide receptors [18, 81]) may be divided into two pairs, RXFP1/2 and RXFP3/4. Endogenous agonists at these receptors are heterodimeric peptide hormones structurally related to insulin: relaxin-1, relaxin, relaxin-3 (also known as INSL7), insulin-like peptide 3 (INSL3) and INSL5. Species homologues of relaxin have distinct pharmacology and relaxin interacts with RXFP1, RXFP2 and RXFP3, whereas mouse and rat relaxin selectively bind to and activate RXFP1 [184]. relaxin-3 is the ligand for RXFP3 but it also binds to RXFP1 and RXFP4 and has differential affinity for RXFP2 between species [183]. INSL5 is the ligand for RXFP4 but is a weak antagonist of RXFP3. relaxin and INSL3 have multiple complex binding interactions with RXFP1 [189] and RXFP2 [91] which direct the N-terminal LDLa modules of the receptors together with a linker domain to act as a tethered ligand to direct receptor signaling [186]. INSL5 and relaxin-3 interact with their receptors using distinct residues in their B-chains for binding, and activation, respectively [225, 104].

The results of the recently published PARAGON-HF trial with sacubitril/valsartan1 have left the scientific community with another formally neutral large-scale trial in heart failure with preserved ejection fraction (HFpEF). The findings of the complementary trial, PARALLAX,2 as presented in the late-breaking trial sessions of the virtual ESC Congress 2020,3 have not really changed this perspective on HFpEF trials, either. Both trials have generated mixed results, at best, with PARAGON-HF narrowly missing its primary endpoint and PARALLAX reaching its primary biomarker-based endpoint, change in N terminal pro brain natriuretic peptide to Week 12, yet being neutral for the co-primary endpoint of the change in 6 min walk test distance to Week 24, and for both secondary endpoints related to quality of life and symptom burden. What currently ignites scientific discussion are the observed significant interactions for both left ventricular ejection fraction and sex.1 The former appears to be embraced, as it appears to make sense to many, and the latter is largely ignored as biological plausibility is questioned. Also, there is no sign for the sex interaction in the PARADIGM-HF trial (investigating the effect of sacubitril/valsartan vs. placebo in heart failure with reduced ejection fraction patients).4 Maybe, the sex interaction in PARAGON-HF (at a P value for interaction of <0.006 for the primary endpoint) is a chance finding. But now, there is some surprising news. In the discussion of PARALLAX after the presentation in the late-breaking trial session at the virtual ESC Congress 2020, it was mentioned that the result for the second primary endpoint of this study (i.e. the change in 6 min walk test distance) also showed a significant sex interaction in favour of women with HFpEF having a benefit from the use of sacubitril/valsartan vs. placebo.3 This comment sets out to explore whether there could be biological plausibility for a sex interaction in the effects of sacubitril/valsartan vs. placebo in HFpEF patients. We suggest two pathways for this. First, effects of endogenous relaxin may cause this sex difference. Second, it is conceivable that the actions of B-type natriuretic peptide (BNP) differ between atria and ventricles, which might explain the striking difference (in terms of presence and absence of the sex interaction) between the PARAGON-HF and PARADIGM-HF trials. At first sight, there could be the following link: angiotensin type-1 receptor (AT1R) blockers (ARBs) have recently been shown to completely block the anti-fibrotic effects of therapeutic relaxin, both in rodent models of renal and cardiac fibrosis and in human cardiac fibroblasts.5, 6 This is attributable to a direct interaction at receptor level—between RXFP1, the cognate receptor for relaxin-2, the AT1R, and the AT2R—and it enables antagonists to each receptor blocking agonist effects at the other receptors.5 In other words, ARBs have been shown in these models to completely nullify relaxin's anti-fibrotic signalling. Until now, it is inconclusive if and which other relaxin effects may be affected by use of ARBs. This could be relevant for therapeutic relaxin. Heterogeneity of the relaxin effects in RELAX-AHF2 and other trials depending on the underlying therapy with ARBs in the patients included there are not known yet, but such analyses could easily be performed. Considering the situation in the clinical studies with sacubitril/valsartan, one has to take into account endogenous relaxin-2. Circulating levels in men are ~300-fold to 500-fold lower than therapeutic levels.7 In women, the ratio depends on menopausal status: during the menstrual cycle, relaxin levels may rise to approximately one-tenth of therapeutic relaxin levels, and this occurs approximately 10 days after the plasma surge of the luteinizing hormone.8 In post-menopausal women, however, levels are similar to those determined in men.7 As a result, these facts may serve to construct a sex difference regarding relaxin-2 and a pharmacological link to the ARB component of the drug under review (i.e. of the valsartan part of sacubitril/valsartan). At closer look, however, there are data that render this hypothesis rather unlikely. The mean age of patients in PARAGON-HF was 73 years. Most if not all women enrolled should have been post-menopausal, which effectively abolishes the said sex difference in endogenous relaxin levels. Moreover, the blockade of relaxin effects by valsartan would have been present in the active control arm as well—then, the sex interaction favouring women's outcome would rather rest in the sacubitril part of the drug to which we presently do not see any clue. Further, we also have to recognize the different design of control groups. PARAGON-HF encompassed one valsartan-treated control group while PARALLAX had three control strata of which only one was on ARBs. For angiotensin-converting enzyme inhibitors, the second PARALLAX stratum, it has been demonstrated that they do not interfere with relaxin effects.9 Lastly, if there is no sex difference regarding circulating relaxin levels, could receptor interaction (RXFP1–AT1R–AT2R) itself be sex-dependent? At present, we have no data corroborating this option (TBD, personal communication). Altogether, these considerations suggest to us that we should dismiss the relaxin hypothesis. Synthetic human relaxin-2, however, is currently being developed for HFpEF, and in spite of its unique pleiotropic signalling, it poses a promising candidate for chronic HFpEF therapy.10 It will therefore be most interesting to explore in pre-clinical HFpEF models, for example, the ZSF1 rat, if and to what extent sacubitril/valsartan interferes with therapeutic relaxin effects. A recent paper by Tsai and co-workers11 may give rise to an alternative explanation. Those researchers focused on atrial BNP effects and referred to previous work in mice indicating tumour necrosis factor (TNF) to induce atrial fibrosis.12 In their work, BNP significantly synergized with TNF and enhanced TNF-induced atrial fibrosis. Furthermore, one hallmark of fibrosis induction and collagen deposition, up-regulation of MMP-2, was also observed in primary human atrial fibroblasts following BNP challenge. Although these results need to be confirmed by other researchers, they raise the possibility that ventricular and atrial BNP effects on extracellular matrix may differ because in ventricles, BNP is well established to counteract fibrosis.13-15 Androgens play a pro-fibrotic role in many circumstances and seem to act in a dual-hit fashion in various contexts. In genetically engineered mice lacking the natriuretic peptide receptor-A (NPR-A aka GC-A), androgens act to produce sex-dependent cardiac fibrosis and hypertrophy,16 with no such effect in the wild-type animals. Of note, down-regulation of NPR-A is a common finding in human heart failure,17 which renders this model even more relevant. In male rats on chronic angiotensin infusion,18 castration greatly reduces angiotensin-related hypertension, cardiac hypertrophy, and fibrosis, and this effect is reversed by testosterone replacement. Furthermore, relaxin-knockout mice show cardiac and renal fibrosis in males only while pulmonary fibrosis is markedly accelerated in males.19 Again, there is no sex-dependent difference in organ fibrosis in the age-matched wild types in this study. Against this background, we may hypothesize that in male HFpEF patients treated with sacubitril/valsartan, elevated BNP acts as second hit in concert with androgens to increase atrial fibrosis. This would potentially account for the difference between PARADIGM-HF vs. PARAGON in terms of the occurrence of a sex interaction. In heart failure with reduced ejection fraction, left atrial changes may be a mere ‘bystander’-type of consequence along the course of disease progression, while in HFpEF, the left atrium takes a more central stage in the pathophysiology of disease progression.20 The strong relation between elevated BNP and the incidence of atrial fibrillation (with atrial fibrosis a major precondition to it) is well established.21 It is mainly regarded as association reflecting heart failure severity, but as we have elaborated here, it may be causal. It is still a serious possibility for the described sex interaction of sacubitril/valsartan vs. placebo in HFpEF, seen in one trial for sure and suggested for a second one, to be a mere chance finding, especially in view of the negative result of the study, which should not allow extrapolation of subgroup analyses. The use of pre-specified subgroups cannot answer all questions, if there are unknown confounders. Post-hoc subgroup analyses have questionable statistical value and can be hypothesis-generating at best. In PARAGON-HF,22 women had lower estimated glomerular filtration rate and N terminal pro brain natriuretic peptide levels at baseline, they were older and more obese, and they had less presence of coronary artery disease. There were differences regarding region and race regarding women and men in this trial. Also, there were regional differences in the effectiveness of the trial with an effect in western Europe similar to that seen in women and in those patients receiving mineralocorticoid receptor antagonists. Further, in regard of the therapeutic effect, the sex difference mainly related to lesser hospitalizations—it did not translate into more pronounced improvements of functional class or KCCQ results in women. Another plausible explanation could be the pharmacodynamic effect of sacubitril/valsartan as women have a smaller volume of distribution than men. A fixed dose regimen may result in higher effective dose in women. This can be relevant with regard to the blood pressure-lowering effect of the medicine. We have not seen the full PARALLAX results yet, to judge in full the extent of validation of the interaction finding of PARAGON-HF in PARALLAX. Furthermore, as already mentioned, the control group in PARALLAX was different with only one of three strata on ARBs. Hence, we will not be able to settle this issue conclusively here. In summary, we have attempted to explore two hypotheses—an ARB interaction with endogenous relaxin and an androgen-dependent pro-fibrotic atrial BNP effect—that could confer biological plausibility to the apparent sex–treatment interaction with sacubitril/valsartan in the PARAGON-HF trial. In the public discussion, a lot of weight is given to the observed ejection fraction-based interaction. The sex interaction is similarly strong, but it is largely ignored so far. Sex differences in ejection fraction are partly used to explain the PARAGON-HF findings. What if we would regard sacubitril/valsartan as the first successful therapy for female patients with HFpEF? Would that be bad for women with HFpEF? There are very many of them, and we think the answer to the question is ‘no’. We simply feel that this issue deserves a closer and more scientific look. Whereas we feel that the relaxin hypothesis is untenable in this context, it may be worthwhile spending more experimental effort to investigate in detail the potentially different effects of BNP at the atrial as opposed to ventricular level. T.B.D. is CEO of Relaxera, a company developing relaxin-2 for cardiovascular indications. S.D.A. reports receiving fees from Abbott, Bayer, Boehringer Ingelheim, Cardiac Dimension, Impulse Dynamics, Novartis, Occlutech, Servier, and Vifor Pharma and grant support from Abbott and Vifor Pharma (all unrelated to this paper).

BACKGROUND Elevated serum levels of parathyroid hormone (PTH), one of the main regulators of calcium homeostasis and vitamin D metabolism, have been proposed as predictors of mortality. The impact of T2DM on the putative association between PTH and mortality has not been investigated thus far. AIM The aim of our study was to investigate the impact of T2DM on the power of PTH to predict mortality risk. METHODS Serum PTH levels were determined in 904 consecutive Caucasian patients referred to coronary angiography for the evaluation of established or suspected stable coronary artery disease (CAD), including 235 patients with T2DM. Prospectively, deaths were recorded over a mean follow-up period of 6.3 years. RESULTS PTH at baseline did not differ significantly between patients with and without T2DM (P=0.307). Cox regression analysis revealed that the serum PTH level strongly predicted all-cause mortality in patients with T2DM (HR=2.35 [1.37-4.03]; P=0.002), whereas PTH did not predict all-cause mortality in patients without T2DM (HR=1.04 [0.81-1.32]; P=0.766). The interaction term PTH x T2DM was significant (P=0.006), indicating a significantly stronger impact of PTH on mortality risk in patients with T2DM than in individuals without diabetes. The impact of PTH on mortality risk in patients with T2DM remained significant after adjustment for HbA1c, diabetes duration, classical cardiovascular risk factors, serum levels of vitamin D and kidney function (HR=2.10 [1.10-4.10]; P=0.030). CONCLUSION We conclude that PTH is a significantly stronger predictor of all-cause mortality in patients with T2DM than in those without T2DM.

Fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH) are regulators of renal phosphate excretion and vitamin D metabolism. In chronic kidney disease (CKD), circulating FGF23 and PTH concentrations progressively increase as renal function declines. Oxidation of PTH at two methionine residues (positions 8 and 18) causes a loss of function. The impact of n-oxPTH and oxPTH on FGF23 synthesis, however, and how n-oxPTH and oxPTH concentrations are affected by CKD, is yet unknown. The effects of oxidized and non-oxidized PTH 1-34 onFgf23gene expression were analyzed in UMR106 osteoblast-like cells. Furthermore, we investigated the relationship between n-oxPTH and oxPTH, respectively, with FGF23 in two independent patients' cohorts (620 children with CKD and 600 kidney transplant recipients). While n-oxPTH stimulatedFgf23mRNA synthesis in vitro, oxidation of PTH in particular at Met8 led to a markedly weaker stimulation ofFgf23. The effect was even stronger when both Met8 and Met18 were oxidized. In both clinical cohorts, n-oxPTH-but not oxPTH-was significantly associated with FGF23 concentrations, independent of known confounding factors. Moreover, with progressive deterioration of kidney function, intact PTH (iPTH) and oxPTH increased substantially, whereas n-oxPTH increased only moderately. In conclusion, n-oxPTH, but not oxPTH, stimulatesFgf23gene expression. The increase in PTH with decreasing GFR is mainly due to an increase in oxPTH in more advanced stages of CKD.

Heart Failure with preserved Ejection Fraction (HFpEF), a distinct sub-entity of chronic heart failure characterized by generalized inflammatory non-compliance of the cardio-vascular system, is associated with high mortality and still an unmet medical need. Many novel and promising therapeutic approaches have failed in large studies. This review focuses on basic research, pre-clinical and clinical findings that may account for the potential benefit of relaxin-2 in HFpEF. The peptide combines short-term hemodynamic advantages, such as moderate blood pressure decline and functional endothelin-1 antagonism, with a wealth of protective effects harboring long-term benefits, such as anti-inflammatory, anti-fibrotic, and anti-oxidative actions. These pleiotropic effects are exerted through a complex and intricate signaling cascade involving the relaxin-family peptide receptor-1, the glucocorticoid receptor, the nitric oxide system, and a cell type-dependent variety of down-stream mediators.

Background: Kynurenine, a metabolite of the L-tryptophan pathway, plays a pivotal role in neuro-inflammation, cancer immunology, and cardiovascular inflammation, and has been shown to predict cardiovascular events. Objectives: It was our objective to increase the body of data regarding the value of kynurenine as a biomarker in chronic heart failure (CHF). Methods: We investigated the predictive value of plasma kynurenine in a CHF cohort (CHF, n = 114); in a second cohort of defibrillator carriers with CHF (AICD, n = 156), we determined clinical and biochemical determinants of the marker which was measured by enzyme immunoassay. Results: In the CHF cohort, both kynurenine and NT-proBNP increased with NYHA class. Univariate binary logistic regression showed kynurenine to predict death within a 6-month follow-up (OR 1.43, 95% CI 1.03–2.00, p = 0.033) whereas NT-proBNP did not contribute significantly. Kynurenine, like NT-proBNP, was able to discriminate at a 30% threshold of left ventricular ejection fraction (LVEF; AUC-ROC, both 0.74). Kynurenine correlated inversely with LVEF (ϱ = –0.394), glomerular filtration fraction (GFR; ϱ = –0.615), and peak VO2 (ϱ = –0.626). Moreover, there was a strong correlation of kynurenine with NT-proBNP (ϱ = 0.615). In the AICD cohort, multiple linear regression analysis demonstrated highly significant associations of kynurenine with GFR, hsCRP, and tryptophan, as well as a significant impact of age. Conclusions: This work speaks in favor of kynurenine being a new and valuable biomarker of CHF, with particular attention placed on its ability to predict mortality and reflect exercise capacity.

Postoperative cognitive impairment is among the most common medical complications associated with surgical interventions - particularly in elderly patients. In our aging society, it is an urgent medical need to determine preoperative individual risk prediction to allow more accurate cost-benefit decisions prior to elective surgeries. So far, risk prediction is mainly based on clinical parameters. However, these parameters only give a rough estimate of the individual risk. At present, there are no molecular or neuroimaging biomarkers available to improve risk prediction and little is known about the etiology and pathophysiology of this clinical condition. In this short review, we summarize the current state of knowledge and briefly present the recently started BioCog project (Biomarker Development for Postoperative Cognitive Impairment in the Elderly), which is funded by the European Union. It is the goal of this research and development (R&D) project, which involves academic and industry partners throughout Europe, to deliver a multivariate algorithm based on clinical assessments as well as molecular and neuroimaging biomarkers to overcome the currently unsatisfying situation. (C) 2017 Published by Elsevier Masson SAS.

Background Homoarginine (hArg) has been shown to be of prognostic value in patients with chronic left heart failure. The present study aims to assess the clinical utility and prognostic value of hArg levels in patients with complex congenital heart disease (CHD). Methods Plasma hArg levels were measured in 143 patients with complex CHD and compared to clinical status, echocardiographic and laboratory parameters as well as the occurrence of adverse cardiac events. Results Median hArg levels were 1.5 μmol/l in CHD patients as compared to 1.70 μmol/l in healthy controls (p = 0.051). Median hArg levels were lowest in patients with Fontan palliation (1.27 μmol/l) and Eisenmenger physiology (0.99 μmol/l) and decreased with the severity of adverse cardiac events with lowest values found in patients prior to death or overt heart failure (0.89 μmol/l). According to ROC analysis, the most important predictors of adverse cardiac events were hArg levels (AUC 0.837, p<0.001, CI 0.726–0.947), NYHA class (AUC 0.800, p<0.001, CI 0.672–0.928) and NT-proBNP levels (AUC 0.780, p<0.001, CI 0.669–0.891). The occurrence of overt heart failure or death due to progressive heart failure were best predicted by NYHA class (AUC 0.945, p<0.001, CI 0.898–0.992), hArg levels (AUC 0.911, p<0.001, CI 0.850–0.971) and NT-proBNP levels (AUC 0.877, p<0.001, CI 0.791–0.962), respectively. Conclusion In patients with complex CHD, hArg levels can predict adverse cardiac events as reliably as or even better than NT-proBNP levels and thus might be of prognostic value in this subset of patients.

Asymmetric dimethylarginine (ADMA) is a competitive inhibitor of the nitric oxide (NO)-synthase and a biomarker of endothelial dysfunction (ED). ED plays an important role in the pathogenesis of contrast-induced nephropathy (CIN). The aim of our study was to evaluate serum ADMA concentration as a biomarker of an acute renal damage during the follow-up of 90 days after contrast medium (CM) application.Blood samples were obtained from 330 consecutive patients with diabetes mellitus or mild renal impairment immediately before, 24 and 48 hours after the CM application for coronary angiography. The patients were followed for 90 days. The composite endpoints were major adverse renal events (MARE) defined as occurrence of death, initiation of dialysis, or a doubling of serum creatinine concentration.Overall, ADMA concentration in plasma increased after CM application, although, there was no differences between ADMA levels in patients with and without CIN. ADMA concentration 24 hours after the CM application was predictive for dialysis with a specificity of 0.889 and sensitivity of 0.653 at values higher than 0.71 μmol/L (area under the curve: 0.854, 95% confidential interval: 0.767-0.941, P < 0.001). This association remained significant in multivariate Cox regression models adjusted for relevant factors of long-term renal outcome. 24 hours after the CM application, ADMA concentration in plasma was predictive for MARE with a specificity of 0.833 and sensitivity of 0.636 at a value of more than 0.70 μmol/L (area under the curve: 0.750, 95% confidence interval: 0.602-0.897, P = 0.004). Multivariate logistic regression analysis confirmed that ADMA and anemia were significant predictors of MARE. Further analysis revealed that increased ADMA concentration in plasma was highly significant predictor of MARE in patients with CIN. Moreover, patients with CIN and MARE had the highest plasma ADMA levels 24 hours after CM exposure in our study cohort. The impact of ADMA on MARE was independent of such known CIN risk factors as anemia, pre-existing renal failure, pre-existing heart failure, and diabetes.ADMA concentration in plasma is a promising novel biomarker of major contrast-induced nephropathy-associated events 90 days after contrast media exposure.

The insulin‐like peptide relaxin, originally identified as a hormone of pregnancy, is now known to exert a range of pleiotropic effects including vasodilatory, anti‐fibrotic, angiogenic, anti‐apoptotic and anti‐inflammatory effects in both males and females. Relaxin produces these effects by binding to a cognate receptor RXFP1 and activating a variety of signalling pathways including cAMP, cGMP and MAPKs as well as by altering gene expression of TGF‐β, MMPs, angiogenic growth factors and endothelin receptors. The peptide has been shown to be effective in halting or reversing many of the adverse effects including fibrosis in animal models of cardiovascular disease including ischaemia/reperfusion injury, myocardial infarction, hypertensive heart disease and cardiomyopathy. Relaxin given to humans is safe and produces favourable haemodynamic changes. Serelaxin, the recombinant form of relaxin, is now in extended phase III clinical trials for the treatment of acute heart failure. Previous clinical studies indicated that a 48 h infusion of relaxin improved 180 day mortality, yet the mechanism underlying this effect is not clear. This article provides an overview of the cellular mechanism of effects of relaxin and summarizes its beneficial actions in animal models and in the clinic. We also hypothesize potential mechanisms for the clinical efficacy of relaxin, identify current knowledge gaps and suggest new ways in which relaxin could be useful therapeutically. Linked Articles This article is part of a themed section on Recent Progress in the Understanding of Relaxin Family Peptides and their Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.10/issuetoc