Altered islet prohormone processing: a cause or consequence of diabetes?

Peptide hormones are first produced as larger precursor prohormones that require endoproteolytic cleavage to liberate the mature hormones. A structurally conserved but functionally distinct family of nine prohormone convertase enzymes (PCs) are responsible for cleavage of protein precursors, of which PC1/3 and PC2 are known to be exclusive to neuroendocrine cells and responsible for prohormone cleavage. Differential expression of PCs within tissues defines prohormone processing; whereas glucagon is the major product liberated from proglucagon via PC2 in pancreatic α-cells, proglucagon is preferentially processed by PC1/3 in intestinal L cells to produce glucagon-like peptides 1 and 2 (GLP-1, GLP-2). Beyond our understanding of processing of islet prohormones in healthy islets, there is convincing evidence that proinsulin, pro-islet amyloid polypeptide (proIAPP), and proglucagon processing is altered during prediabetes and diabetes. There is predictive value of elevated circulating proinsulin or proinsulin-to-C-peptide ratio for progression to type 2 diabetes, and elevated proinsulin or proinsulin-to-C-peptide ratio is predictive for development of type 1 diabetes in at-risk groups. After onset of diabetes, patients have elevated circulating proinsulin and proIAPP, and proinsulin may be an autoantigen in type 1 diabetes. Furthermore, preclinical studies reveal that α-cells have altered proglucagon processing during diabetes, leading to increased GLP-1 production. We conclude that despite strong associative data, current evidence is inconclusive on the potential causal role of impaired prohormone processing in diabetes and suggest that future work should focus on resolving the question of whether altered prohormone processing is a causal driver or merely a consequence of diabetes pathology.

Mapping prohormone processing by proteases in human enteroendocrine cells using genetically engineered organoid models.

Enteroendocrine cells (EECs) secrete hormones in response to ingested nutrients to control physiological processes such as appetite and insulin release. EEC hormones are synthesized as large proproteins that undergo proteolytic processing to generate bioactive peptides. Mutations in EEC-enriched proteases are associated with endocrinopathies. Due to the relative rarity of EECs and a paucity of in vitro models, intestinal prohormone processing remains challenging to assess. Here, human gut organoids in which EECs can efficiently be induced are subjected to CRISPR-Cas9-mediated modification of EEC-expressed endopeptidase and exopeptidase genes. We employ mass spectrometry-based analyses to monitor peptide processing and identify glucagon production in intestinal EECs, stimulated upon bone morphogenic protein (BMP) signaling. We map the substrates and products of major EECs endo- and exopeptidases. Our studies provide a comprehensive description of peptide hormones produced by human EECs and define the roles of specific proteases in their generation.

Metformin restores prohormone processing enzymes and normalizes aberrations in secretion of proinsulin and insulin in palmitate-exposed human islets.

AIM: To elucidate how proinsulin synthesis and insulin was affected by metformin under conditions of nutrient overstimulation. MATERIALS AND METHODS: Isolated human pancreatic islets from seven donors were cultured at 5.5 mmol/L glucose and 0.5 mmol/L palmitate for 12, 24 or 72 h. Metformin (25 µmol/L) was introduced after initial 12 h with palmitate. Proinsulin and insulin were measured. Expression of prohormone convertase 1/3 (PC1/3) and carboxypeptidase E (CPE), was determined by western blot. Adolescents with obesity, treated with metformin and with normal glucose tolerance (n = 5), prediabetes (n = 14), or type 2 diabetes (T2DM; n = 7) were included. Fasting proinsulin, insulin, glucose, 2-h glucose and glycated haemoglobin were measured. Proinsulin/insulin ratio (PI/I) was calculated. RESULTS: In human islets, palmitate treatment for 12 and 24 h increased proinsulin and insulin proportionally. After 72 h, proinsulin but not insulin continued to increase which was coupled with reduced expression of PC1/3 and CPE. Metformin normalized expression of PC1/3 and CPE, and proinsulin and insulin secretion. In adolescents with obesity, before treatment, fasting proinsulin and insulin concentrations were higher in subjects with T2DM than with normal glucose tolerance. PI/I was reduced after metformin treatment in subjects with T2DM as well as in subjects with prediabetes, coupled with reduced 2-h glucose and glycated haemoglobin. CONCLUSIONS: Metformin normalized proinsulin and insulin secretion after prolonged nutrient-overstimulation, coupled with normalization of the converting enzymes, in isolated islets. In adolescents with obesity, metformin treatment was associated with improved PI/I, which was coupled with improved glycaemic control.

Unravelling the neuropeptidome of the ornate spiny lobster Panulirus ornatus: A focus on peptide hormones and their processing enzymes expressed in the reproductive tissues.

Neuropeptides are commonly produced in the neural tissues yet can have effects on far-reaching targets, with varied biological responses. We describe here the neuropeptidome of the ornate spiny lobster, Panulirus ornatus, a species of emerging importance to closed-system aquaculture, with a focus on peptide hormones produced by the reproductive tissues. Transcripts for a precursor to one neuropeptide, adipokinetic hormone/corazonin-related peptide (ACP) were identified in high numbers in the sperm duct of adult spiny lobsters suggesting a role for ACP in the reproduction of this species. Neuropeptide production in the sperm duct may be linked with physiological control of spermatophore production in the male, or alternatively may function in signalling to the female. The enzymes which process nascent neuropeptide precursors into their mature, active forms have seldom been studied in decapods, and never before at the multi-tissue level. We have identified transcripts for multiple members of the proprotein convertase subtisilin/kexin family in the ornate spiny lobster, with some enzymes showing specificity to certain tissues. In addition, other enzyme transcripts involved with neuropeptide processing are identified along with their tissue and life stage expression patterns.

Plasma N-terminal pro-B-type natriuretic peptide in the detection of aortic valve stenosis.

BACKGROUND: Systolic murmur suggestive of aortic valve origin is a common accidental finding, particularly in the elderly. Usually, it is due to aortic stenosis (AS) or aortic sclerosis (ASc). Currently, echocardiography is used to differentiate AS from ASc. Plasma N-terminal (NT)-prohormone BNP (NT-proBNP) is known to correlate with the severity of AS. We assessed whether NT-proBNP separates AS from ASc. METHODS: The study population consisted of three groups: AS (n = 87, age 77 ± 7 years), ASc (n = 76, age 72 ± 10 years), and healthy controls (n = 101, age 55 ± 10 years). All subjects underwent transthoracic echocardiography and measurement of plasma NT-proBNP. Patients with diseases known to increase NT-proBNP were excluded. RESULTS: The crude plasma NT-proBNP (median; IQR) in AS patients (413; 165-1055 ng/l) was significantly higher compared to ASc patients (96; 53-237 ng/l, p < 0.001) and healthy controls (50; 29-76 ng/l, p < 0.001). After adjusting for the confounding factors (age, coronary artery disease, renal function and diastolic blood pressure), plasma NT-proBNP remained significantly higher in AS patients as compared to ASc (p < 0.002) and controls (p < 0.0001). In the receiver-operating characteristic curve for NT-proBNP to identify AS from ASc and controls, the area under the curve was 0.878 with optimal cutoff of 115 ng/l. In addition, using 115 ng/l to separate AS from ASc yielded sensitivity of 0.885, and negative predictive value of 0.808. CONCLUSIONS: NT-proBNP was sensitive to identify AS and useful to rule out AS in patients with systolic murmur in the left ventricular outflow tract provided the patient does not have coexisting disease known to impact NT-proBNP.

Cardiac Biomarkers Aid in Differentiation of Kawasaki Disease from Multisystem Inflammatory Syndrome in Children Associated with COVID-19.

Kawasaki disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C) associated with COVID-19 show clinical overlap and both lack definitive diagnostic testing, making differentiation challenging. We sought to determine how cardiac biomarkers might differentiate KD from MIS-C. The International Kawasaki Disease Registry enrolled contemporaneous KD and MIS-C pediatric patients from 42 sites from January 2020 through June 2022. The study population included 118 KD patients who met American Heart Association KD criteria and compared them to 946 MIS-C patients who met 2020 Centers for Disease Control and Prevention case definition. All included patients had at least one measurement of amino-terminal prohormone brain natriuretic peptide (NTproBNP) or cardiac troponin I (TnI), and echocardiography. Regression analyses were used to determine associations between cardiac biomarker levels, diagnosis, and cardiac involvement. Higher NTproBNP (≥ 1500 ng/L) and TnI (≥ 20 ng/L) at presentation were associated with MIS-C versus KD with specificity of 77 and 89%, respectively. Higher biomarker levels were associated with shock and intensive care unit admission; higher NTproBNP was associated with longer hospital length of stay. Lower left ventricular ejection fraction, more pronounced for MIS-C, was also associated with higher biomarker levels. Coronary artery involvement was not associated with either biomarker. Higher NTproBNP and TnI levels are suggestive of MIS-C versus KD and may be clinically useful in their differentiation. Consideration might be given to their inclusion in the routine evaluation of both conditions.

Usefulness of the N-Terminal of the Prohormone Brain Natriuretic Peptide in Predicting Acute Kidney Injury Requiring Renal Replacement Therapy in Patients Undergoing Heart Valve Surgery.

Background and Objectives: By definition, acute kidney injury (AKI) is a clinical syndrome diagnosed when the increase in serum creatinine concentration is >0.3 mg/dL in 48 h or >1.5-fold in the last seven days or when diuresis < 0.5 mL/kg/h for a consecutive 6 h. AKI is one of the severe complications that may occur in the early postoperative period in patients undergoing heart valve surgery, significantly increasing the risk of death. Early implementation of renal replacement therapy increases the chances of improving treatment results in patients with postoperative AKI. The study assessed the predictive ability of selected preoperative and perioperative parameters for the occurrence of postoperative AKI requiring renal replacement therapy in the early postoperative period in a group of patients with severe valvular heart disease. Materials and Methods: A prospective study was conducted on a group of patients undergoing consecutive heart valve surgeries. The primary endpoint was postoperative AKI requiring renal replacement therapy. AKI was diagnosed with an increase in serum creatinine > 0.3 mg/dL in 48 h or >1.5-fold in the previous 7 days and/or a decrease in diuresis < 0.5 mL/kg/h for 6 h. The observation period was until the patient was discharged home or death occurred. Logistic regression analysis was used to assess which variables were predictive of primary endpoint, and odds ratios (OR) were calculated with a 95% confidence interval (CI). Multivariate analysis was based on the result of single factor logistic regression, i.e., to further steps, all statistically significant variables were taken into consideration. Results: A total of 607 patients were included in the study. The primary endpoint occurred in 50 patients. At multivariate analysis: NT-proBNP (OR 1.406; 95% CI 1.015-1.949; p = 0.04), CRP (OR 1.523; 95% CI 1.171-1.980; p = 0.001), EuroSCORE II (OR 1.090; 95% CI 1.014-1.172; p = 0.01), age (OR 1.037; 95% CI 1.001-1.075; p = 0.04) and if they stayed in the intensive care unit longer than 2 days (OR 9.077; 95% CI 2.026-40.663; p = 0.004) remained the independent predictors of the primary endpoint. The mean preoperative NT-proBNP level was 2063 pg/mL (±1751). Thirty-eight patients with AKI requiring renal replacement therapy died in intrahospital follow-up. Conclusions: The results of the presented study indicate that a high preoperative level of NT-proBNP and postoperative hemodynamic instability may be associated with a significant risk of a postoperative AKI requiring renal replacement therapy. The results of the study may also suggest that qualifying for heart valve surgery earlier may be associated with improved prognosis in this group of patients.

From Habitat to Hormones: Year-around territorial behavior in rock-dwelling but not in forest and grassland lagomorphs and the role of DHEA.

Year-around defense of extremely patchy habitat may require hormones that drive territorial behavior, but have no other costly physiological effects. The American pika (Ochotona princeps), but not the snowshoe hare (Lepus americanus) nor the eastern cottontail rabbit (Sylvilagus floridanus), exhibits this behavior. The former engages in contest competition against all individuals independent of sex to protect its territory in highly fragmented patches on mountain talus slopes; the latter in scramble competition in more continuous forests, grasslands, and shrublands. The hormonal basis for this difference in lagomorphs is unknown. Dehydroepiandrosterone is a prohormone produced by the zona reticularis of the adrenal cortex. It has no effect on aggressive behavior until converted in the brain to estrogen. We assessed levels (DHEA-S plus DHEA) in all species collected in the wild. In nonbreeding pikas, levels were 256 times higher than in hares and 22 times higher than in rabbits. Within species, females and males had similar levels. The proportion of the adrenal cortex devoted to the zona reticularis was significantly larger in pikas than in hares or rabbits. Our evidence is consistent with the hypothesis that dehydroepiandrosterone drives this individual-based, year-around territoriality in pikas. We propose a definitive experiment to determine this and recommend comparative studies in central Asia where there is high diversity of pika species whose behavior ranges from individual-based territoriality to colonial. Thus, we speculate that the wild American pika has the adrenal-brain nexus for all seasons and is an excellent model to understand how habitat drives the hormonal control of spacing behavior.

Selective auxin agonists induce specific AUX/IAA protein degradation to modulate plant development.

Auxin phytohormones control most aspects of plant development through a complex and interconnected signaling network. In the presence of auxin, AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) transcriptional repressors are targeted for degradation by the SKP1-CULLIN1-F-BOX (SCF) ubiquitin-protein ligases containing TRANSPORT INHIBITOR RESISTANT 1/AUXIN SIGNALING F-BOX (TIR1/AFB). CULLIN1-neddylation is required for SCFTIR1/AFB functionality, as exemplified by mutants deficient in the NEDD8-activating enzyme subunit AUXIN-RESISTANT 1 (AXR1). Here, we report a chemical biology screen that identifies small molecules requiring AXR1 to modulate plant development. We selected four molecules of interest, RubNeddin 1 to 4 (RN1 to -4), among which RN3 and RN4 trigger selective auxin responses at transcriptional, biochemical, and morphological levels. This selective activity is explained by their ability to consistently promote the interaction between TIR1 and a specific subset of AUX/IAA proteins, stimulating the degradation of particular AUX/IAA combinations. Finally, we performed a genetic screen using RN4, the RN with the greatest potential for dissecting auxin perception, which revealed that the chromatin remodeling ATPase BRAHMA is implicated in auxin-mediated apical hook development. These results demonstrate the power of selective auxin agonists to dissect auxin perception for plant developmental functions, as well as offering opportunities to discover new molecular players involved in auxin responses.

Change in Cardiac Biomarkers and Risk of Incident Heart Failure and Atrial Fibrillation in CKD: The Chronic Renal Insufficiency Cohort (CRIC) Study.

RATIONALE & OBJECTIVE: Circulating cardiac biomarkers may signal potential mechanistic pathways involved in heart failure (HF) and atrial fibrillation (AF). Single measures of circulating cardiac biomarkers are strongly associated with incident HF and AF in chronic kidney disease (CKD). We tested the associations of longitudinal changes in the N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP), high-sensitivity troponin T (hsTnT), galectin-3, growth differentiation factor 15 (GDF-15), and soluble ST-2 (sST-2) with incident HF and AF in patients with CKD. STUDY DESIGN: Observational, case-cohort study design. SETTING & PARTICIPANTS: Adults with CKD enrolled in the Chronic Renal Insufficiency Cohort study. EXPOSURES: Biomarkers were measured at baseline and 2 years later among those without kidney failure. We created 3 categories of absolute change in each biomarker: the lowest quartile, the middle 2 quartiles, and the top quartile. OUTCOMES: The primary outcomes were incident HF and AF. ANALYTICAL APPROACH: Cox proportional hazards regression models were used to test the associations of the change categories of each cardiac biomarker with each outcome (with the middle 2 quartiles of change as the referent group), adjusting for potential confounders and baseline concentrations of each biomarker. RESULTS: The incident HF analysis included 789 participants (which included 138 incident HF cases), and the incident AF analysis included 774 participants (123 incident AF cases). In multivariable models, the top quartile of NT-proBNP change (>232pg/mL over 2years) was associated with increased risk of incident HF (HR, 1.79 [95% CI, 1.06-3.04]) and AF (HR, 2.32 [95% CI, 1.37-3.93]) compared with the referent group. Participants in the top quartile of sST2 change (>3.37ng/mL over 2years) had significantly greater risk of incident HF (HR, 1.89 [95% CI, 1.13-3.16]), whereas those in the bottom quartile (≤-3.78ng/mL over 2years) had greater risk of incident AF (HR, 2.43 [95% CI, 1.39-4.22]) compared with the 2 middle quartiles. There was no association of changes in hsTnT, galectin-3, or GDF-15 with incident HF or AF. LIMITATIONS: Observational study. CONCLUSIONS: In CKD, increases in NT-proBNP were significantly associated with greater risk of incident HF and AF, and increases in sST2 were associated with HF. Further studies should investigate whether these markers of subclinical cardiovascular disease can be modified to reduce the risk of cardiovascular disease in CKD.

Prevalence of and Factors Associated with Dietary Supplement Use in a Stratified, Random Sample of US Military Personnel: The US Military Dietary Supplement Use Study.

BACKGROUND: About 50% of Americans and 70% of US military service members use dietary supplements (DSs). OBJECTIVES: This cross-sectional survey examined current prevalence of and factors associated with DS use in service members. METHODS: A stratified random sample of 200,000 service members from the Air Force, Army, Marine Corps, and Navy was obtained from military manpower records, and these service members were asked to complete a questionnaire on their DS use and personal characteristics. Chi-square statistics and multivariable logistic regression examined differences across various strata of demographic, lifestyle, and military characteristics. RESULTS: About 18% of successfully contacted service members (n = 26,681) completed the questionnaire between December 2018 and August 2019 (mean ± SD age: 33 ± 8 y, 86% male). Overall, 74% reported using ≥1 DS/wk. Multivitamins/multiminerals were the most commonly used DSs (45%), followed by combination products (44%), proteins/amino acids (42%), individual vitamins/minerals (31%), herbals (20%), joint health products (9%), and purported prohormones (5%). In multivariable analysis, factors independently associated with DS use included female gender [OR (female/male): 1.91; 95% CI: 1.73, 2.11], older age [OR (≥40/18-24 y): 1.25; 95% CI: 1.08, 1.44], higher education level [OR (college degree/high school or less): 1.35; 95% CI: 1.19, 1.53], higher BMI [OR (≥30/<25 kg/m2): 1.37; 95% CI: 1.25, 1.52], more weekly resistance training [OR (>300/≤45 min/wk): 5.05; 95% CI: 4.55, 5.61], smokeless tobacco use [OR (user/nonuser): 1.30; 95% CI: 1.17, 1.44], higher alcohol intake [OR (≥72/0 mL/wk): 1.41; 95% CI: 1.29, 1.54], and higher military rank [OR (senior officer/junior enlisted): 1.26; 95% CI: 1.06, 1.51]. CONCLUSIONS: Compared with civilian data from the NHANES, service members were much more likely to use DSs and used different types of DSs, especially combination products and proteins/amino acids often used to purportedly enhance physical performance. Comparisons with previous military data suggest DS use has increased over time.

In vitro effect of DDE exposure on the regulation of B-TC-6 pancreatic beta cell insulin secretion: a potential role in beta cell dysfunction and type 2 diabetes mellitus.

Organochlorine compounds (OC) include synthetic insecticides previously used throughout the world before being banned for their adverse effects and environmental persistence; DDT (dichlorodiphenyltrichloroethane) was one of the most widely used. Epidemiological evidence suggests that higher levels of some OC, including metabolites of DDT, such as dichlorodiphenyldichloroethylene (DDE), are associated with type 2 diabetes mellitus (T2D). DDE exposure may affect pancreatic cellular functions associated with glucose control and possibly cause beta cell dysfunction. The in vitro effect of DDE exposure on pancreatic beta cell insulin secretion was investigated using Beta-Tumor Cell-6 (B-TC-6) murine pancreatic beta cells. DDE exposure significantly increased insulin secretion suggesting a role for DDE in altering insulin synthesis and secretion. Reactive oxygen species (ROS) levels were not significantly increased indicating that oxidative stress is not responsible for the DDE-induced insulin secretion. Pancreatic and duodenal homeobox factor-1 (PDX-1) levels were not significantly increased suggesting that DDE exposure does not alter insulin transcription, but prohormone convertase (PC) levels were increased suggesting a role for DDE in altering insulin translation. Based on these in vitro results, DDE may play a role in beta cell dysfunction by affecting mechanisms that regulate insulin secretion but it is not likely to be the major mechanism behind the DDE/T2D epidemiological association.

Diagnostic significance of stimulating growth factor ST2 and N-terminal prohormone of brain natriuretic peptide NT-PROBNP in patients with ischemic heart disease in the setting of metabolic syndrome.

Ischemic heart disease (IHD) is the leading cause of death and disability in many countries. The development of IHD is affected by a number of diseases, including metabolic syndrome (MS). Modern predictors of IHD include stimulating growth factor (ST2) and N-terminal prohormone of brain natriuretic peptide (NT-proBNP). AIM: The aim of the study was to investigate serum ST2 and NT-proBNP levels in patients with IHD and in patients with IHD in the setting of MS. MATERIALS AND METHODS: The concentrations levels of ST2 and NTproBNP were investigated using an enzyme-linked immunoassay in 20 patients with verified IHD. 8 patients had IHD without MS (5 males, 3 females) and 10 patients had MS (9 males and 1 female). The mean age of patients was 55 ± 2 years. The control group included 20 virtually healthy, age- and gender-matched individuals. RESULTS: Serum concentrations of ST2 in patients with IHD in the setting of MS were 31% above normal (p<0.05). In MS-free patients with IHD, serum levels of ST2 were 16% above those in controls (p<0.05). Serum concentration levels of NT-proBNP in patients with IHD in the setting of metabolic syndrome were 62% above normal (p<0.05), while NT-proBNP levels in MS-free patients with IHD were within normal (p>0.05). It was established strong positive correlations between ST2 and NT-proBNP concentration levels (r = 0.90; p<0.05). CONCLUSIONS: Based on the completed analysis of laboratory data, a conclusion can be made that concentrations of ST2 correlates positively with NT-proBNP values in patients with IHD in the setting of MS, which may suggest the presence of ischemic and metabolic disorders in these patients.

Translation of insulin granule proteins are regulated by PDI and PABP.

Glucose mediated insulin biosynthesis is tightly regulated and shared between insulin granule proteins such as its processing enzymes, prohormone convertases, PC1/3 and PC2. However, the molecular players involved in the co-ordinated translation remain elusive. The trans-acting factors like PABP (Poly A Binding Protein) and PDI (Protein Disulphide Isomerize) binds to a conserved sequence in the 5'UTR of insulin mRNA and regulates its translation. Here, we demonstrate that 5'UTR of PC1/3 and PC2 also associate with PDI and PABP. We show that a' and RRM 3-4 domains of PDI and PABP respectively, are necessary for RNA binding activity to the 5'UTRs of insulin and its processing enzymes.

Stabilization patterns and variability of hs-CRP, NT-proBNP and ST2 during 1 year after acute coronary syndrome admission: results of the BIOMArCS study.

Objectives Details of the biological variability of high-sensitivity C-reactive protein (hs-CRP), N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and ST2 are currently lacking in patients with acute coronary syndrome (ACS) but are crucial knowledge when aiming to use these biomarkers for personalized risk prediction. In the current study, we report post-ACS kinetics and the variability of the hs-CRP, NT-proBNP and ST2. Methods BIOMArCS is a prospective, observational study with high frequency blood sampling during 1 year post-ACS. Using 1507 blood samples from 191 patients that remained free from adverse cardiac events, we investigated post-ACS kinetics of hs-CRP, NT-proBNP and ST2. Biological variability was studied using the samples collected between 6 and 12 months after the index ACS, when patients were considered to have stable coronary artery disease. Results On average, hs-CRP rose peaked at day 2 and rose well above the reference value. ST2 peaked immediately after the ACS but never rose above the reference value. NT-proBNP level rose on average during the first 2 days post-ACS and slowly declined afterwards. The within-subject variation and relative change value (RCV) of ST2 were relatively small (13.8%, RCV 39.7%), while hs-CRP (41.9%, lognormal RCV 206.1/-67.3%) and NT-proBNP (39.0%, lognormal RCV 185.2/-64.9%) showed a considerable variation. Conclusions Variability of hs-CRP and NT-proBNP within asymptomatic and clinically stable post-ACS patients is considerable. In contrast, within-patient variability of ST2 is low. Given the low within-subject variation, ST2 might be the most useful biomarker for personalizing risk prediction in stable post-ACS patients.

Paired Basic Amino Acid-cleaving Enzyme 4 (PCSK6): An Emerging New Target Molecule in Human Melanoma.

Although recent therapeutic developments raise hope, melanoma remains a devastating disease with a need for new treatment targets. In other tumours prohormone convertases have been shown to be pro-tumourigenic as they are involved in processing preforms of matrix-metalloproteinases, growth factors and adhesion molecules. The aim of this study was to look for new treatment options for melanoma, by investigating the role of the prohormone convertase Paired basic Amino acid-Cleaving Enzyme 4 (PACE4/PCSK6) in melanoma cell lines and human melanoma tissue. PACE4-transfected A375 melanoma cells displayed significantly increased proliferation, MMP-2 production, gelatinase activity and migratory capacity in vitro compared with sham-transfected cells. In vivo, elevated PACE4 expression resulted in significantly increased tumour growth on immunodeficient mice. In the majority of 45 human primary melanomas and melanoma metastases ex vivo PACE4 immunoreactivity was detectable, while it was absent in in situ melanomas. These results indicate PACE4 as a regulator of melanoma cell aggressiveness.

Alendronate slows down aortic stenosis progression in osteoporotic patients: An observational prospective study.

BACKGROUND: Aortic stenosis (AS) is the most common primary valvular disease. Currently, there is no pharmacological approach for the medical management of AS. We investigated the effect of osteoporosis therapy with alendronate on hemodynamic progression in patients concurrently affected by AS and osteoporosis. MATERIALS AND METHODS: In this observational prospective study, we enrolled 37 women more than 60 years old with diagnosis of AS and concurrent osteoporosis from August 2017 to December 2019. These patients were treated with alendronate 70 mg every week added to their routine treatment for AS, and their outcomes were compared with 33 patients only affected by AS. Echocardiographic changes and N-terminal-prohormone of brain natriuretic peptide (NT-pro-BNP) level were evaluated during about 2 years of follow-up. RESULTS: The mean follow-up time for the treated and nontreated groups was 20.89 ± 2.73 and 20.84 ± 2.76 months, respectively. Mean gradient (P = 0.02) and peak gradient (P = 0.04) of aortic valve were significantly different between the groups after follow-up. Aortic valve area was decreased 0.09 cm2 in the treated group by alendronate and 0.23 cm2 in the other group (P = 0.001). Furthermore, NT-pro-BNP was significantly decreased in patients treated by alendronate (P = 0.01), but it was increased in nontreated patients (P = 0.04). CONCLUSION: Treatment with alendronate in patients with AS and concurrent osteoporosis slows down the progression of stenosis and improves their prognosis. This study could open a new pathway for the treatment of AS. Further studies, particularly randomized controlled clinical trial, should be done for providing more evidence.

Clinical and neurohumoral associates of variations in plasma Na+ in the PREVEND cohort.

Plasma Na+ concentration is regulated within narrow limits. Yet, substantial interindividual differences exist even in the normal range. The determinants of these differences are not well understood. We therefore investigated the clinical and neurohumoral associates of plasma Na+. We studied 2,364 men (age: 48 ± 12 yr) and 2,710 women (age: 47 ± 12 yr) from the prospective Prevention of Renal and Vascular End-Stage Disease (PREVEND) cohort study. In the present study, we investigated the neurohumoral factors NH2-terminal prohormone of brain natriuretic peptide (NT-proBNP) and aldosterone as volume markers and copeptin as a marker for osmoregulation. Clinical associating variables of plasma Na+ were age, sex, and plasma glucose. Furthermore, plasma Na+ levels were associated with log2 copeptin (men: standardized ß = 0.18, P < 0.001; women: standardized ß = 0.17, P < 0.001), log2 NT-proBNP (men: standardized ß = 0.07, P = 0.008; women: standardized ß = 0.12, P < 0.001), and log2 aldosterone (men: standardized ß = -0.06, P = 0.005; women: standardized ß = -0.09, P < 0.001). Copeptin and NT-proBNP showed an interaction in their association with plasma Na+. Thus, our data 1) support that osmoregulation, as estimated from copeptin levels, is a main associate of plasma Na+; 2) show a consistent association with volume markers, with higher NT-proBNP and lower aldosterone in individuals with higher plasma Na+; and 3) show that the interaction between copeptin and NT-proBNP illustrates that osmoregulation and volume regulation act in concert in the regulation of plasma Na+.

Sex-specific effects of dehydroepiandrosterone (DHEA) on bone mineral density and body composition: A pooled analysis of four clinical trials.

OBJECTIVE: Studies of dehydroepiandrosterone (DHEA) therapy in older adults suggest sex-specific effects on bone mineral density (BMD) and body composition, but the ability of a single study to reach this conclusion was limited. We evaluated the effects of DHEA on sex hormones, BMD, fat mass and fat-free mass in older women and men enrolled in four similar clinical trials. DESIGN: Pooled analyses of data from four double-blinded, randomized controlled trials. PARTICIPANTS: Women (n = 295) and men (n = 290) aged 55 years or older who took DHEA or placebo tablet daily for 12 months. MEASUREMENTS: Twelve-month changes in BMD, fat mass, fat-free mass and serum DHEA sulphate (DHEAS), (17)estradiol, testosterone and insulin-like growth factor-1 (IGF-1). RESULTS: Women on DHEA had increases (mean ± SD; all P < 0.001 vs placebo) in DHEAS (231 ± 164 µg/dL), testosterone (18.6 ± 20.9 µg/dL), (17)estradiol (8.7 ± 11.0 pg/mL) and IGF-1 (25.1 ± 52.3 ng/mL), and men had increases in DHEAS (269.0 ± 177 µg/dL; P < 0.01), (17)estradiol (4.8 ± 12.2 pg/m; P < 0.01) and IGF-1 (6.3 ± 41.4 ng/mL; P < 0.05). Women on DHEA had increases in lumbar spine (1.0% ± 3.4%) and trochanter (0.5% ± 3.8%) BMD and maintained total hip BMD (0.0% ± 2.8%); men had no BMD benefit and a decrease in fat mass (-0.4 ± 2.6 kg; all P < 0.01 vs placebo). CONCLUSIONS: Dehydroepiandrosterone therapy may be an effective approach for preserving bone and muscle mass in women. Key questions are (a) the extent to which longer duration DHEA can attenuate the loss of bone and muscle in women, and (b) whether DHEA has a more favourable benefit-to-risk profile for women than oestrogen therapy.