Proenkephalin Research Articles

Proenkephalin improves risk prediction in acute coronary syndromes: derivation and external validation of the KID-ACS risk score

Abstract Background Early assessment of renal and mortality risk in patients with acute coronary syndromes (ACS) is essential to guide treatment decisions according to international guidelines. Circulating proenkephalin (PENK) is a stable opioid metabolite with fast response to changes in kidney function. Purpose This study examined the predictive value of PENK for acute kidney injury (AKI) and mortality in patients presenting with acute coronary syndromes (ACS). Methods Plasma PENK levels were measured using a validated sandwich immunoassay in a prospective multicentre ACS cohort from Switzerland (n = 4 787) and in validation cohorts from the UK (n = 1 141) and Czechia (n = 920). A biomarker-enhanced risk score for simultaneous prediction of both in-hospital acute kidney injury (AKI) and 30-day death (KID-ACS score) with model coefficients adjusted to the outcome was derived and externally validated. In the development of the in-hospital AKI model, patients from one participating study centre were reserved for external validation (Swiss validation cohort). Results Circulating PENK ranked among the top predictors of renal outcomes and mortality in patients with ACS. Accounting for established risk factors and risk models, circulating PENK levels at presentation were independently associated with in-hospital AKI (per log2 increase: adjusted odds ratio [OR] 1.56, 95% CI 1.14 – 2.12, P = 0.005) and with 30-day mortality (per log2 increase: adjusted OR 2.69, 95% CI 1.89 – 3.84, P < 0.001). Dynamic changes in PENK levels within the first 12-24 hours after presentation were strongly and independently associated with in-hospital AKI (increase vs. decrease: adjusted OR 2.83, 95% CI 1.98 – 4.05, P < 0.001). The simple 6-item KID-ACS risk score for in-hospital AKI and 30-day mortality integrates PENK levels at presentation and showed an AUC of 0.72 (95% CI 0.68 – 0.76) for in-hospital AKI, and of 0.91 (95% CI 0.87 – 0.95) for 30-day mortality in the derivation cohort. Upon external validation, KID-ACS had similarly high performance for in-hospital AKI (Swiss validation cohort: AUC 0.73, 95% CI 0.70 – 0.77; Czech validation cohort: 0.74, 95% CI 0.68 – 0.80) and 30-day mortality (UK validation cohort: AUC of 0.87, 95% CI 0.82 – 0.91; Czech validation cohort: 0.91, 95% CI 0.87 – 0.94). The simple 6-item KID-ACS score was non-inferior to established risk models and significantly outperformed the CA-AKI risk score in predicting in-hospital AKI (Zurich cohort: delta AUC 0.11, 95% CI 0.07 – 0.15, P = 0.001) and the GRACE 2.0 in predicting 30-day mortality (UK cohort: delta AUC 0.05, 95% CI 0.01 – 0.09, P = 0.027). Conclusions Circulating PENK was identified as independent predictor of in-hospital AKI and 30-day mortality in patients with ACS. The simple 6-item KID-ACS risk score integrates circulating PENK levels and provides a novel tool for simultaneous assessment of renal and mortality risk in patients presenting with ACS.Independent Predictive Value PENKPerformance and validation of KID-ACS

P091 PROENKEPHALIN CONCENTRATION AND ITS DETERMINANTS IN PATIENTS WITH END-STAGE KIDNEY DISEASE TREATED WITH HEMODIALYSIS AND PERITONEAL DIALYSIS

Background and Objective. Proenkephalin (PENK) has been recently shown to reflect glomerular dysfunction and predict new-onset acute kidney injury and heart failure. While previous studies investigated PENK utility in individuals with preserved renal function, PENK concentration in patients with end-stage kidney disease (ESKD) remained to be established. The study aimed to assess plasma PENK concentration in patients with end-stage kidney disease (ESKD) treated with hemodialysis (HD) and peritoneal dialysis (PD) and to investigate its correlation with heart failure. Additionally, we aimed to determine whether PENK is removed during a hemodialysis session. Methods. 88 patients with ESKD (41 females) undergoing HD (n=66, 75%) and PD (n=22, 25%) were enrolled in this cross-sectional study. Blood samples for PENK determination were collected before and at the end of the hemodialysis session in HD patients and at a single time point in PD patients. Plasma proenkephalin concentration was assessed using a sandwich ELISA immunoassay. Samples for measurement of creatinine, urea, and NT-proBNP were drawn simultaneously. Results. The median (IQR) plasma PENK concentration in the overall population was 1.492 ng/ml (1.071-4.380). Both median eGFR (5 mL/min/1.73 m2 [4-7] vs. 5 mL/min/1.73 m2 [4-8], p=0,856) and plasma PENK levels (1.368 ng/ml [1.068-4.030] vs. 1.706 ng/ml [1.211-5.858], p=0.305) did not differ significantly between HD and PD patients. In HD patients, median PENK concentration was significantly higher before than after hemodialysis (1.368 vs. 2.061; p=0.003). No correlation was found between PENK level and urea (p=0.192), eGFR (p=0.922), duration of dialysis (p=0.637), and residual urine output (p=0.784). Heart failure (p=0.961), EF (p=0.361), and NT-proBNP (p=0.949) were not associated with increased PENK concentration. Conclusions. Our study proved that PENK is not removed during hemodialysis session. PENK concentration does not reflect renal function and cardiac status in patients with ESKD. The fact that PENK is not removed by hemodialysis calls into question the usefulness of PENK as an everyday use biomarker in acute kidney injury.

Proenkephalin Improves Cardio-Renal Risk Prediction in Acute Coronary Syndromes: The KID-ACS Score.

Circulating proenkephalin (PENK) is a stable endogenous polypeptide with fast response to glomerular dysfunction and tubular damage. This study examined the predictive value of PENK for renal outcomes and mortality in patients with acute coronary syndromes (ACS). Proenkephalin was measured in plasma in a prospective multicentre ACS cohort from Switzerland (n=4787) and in validation cohorts from the UK (n=1141), Czechia (n=927), and Germany (n=220). A biomarker-enhanced risk score (KID-ACS score) for simultaneous prediction of in-hospital acute kidney injury (AKI) and 30-day mortality was derived and externally validated. On multivariable adjustment for established risk factors, circulating PENK remained associated with in-hospital AKI (per log2 increase: adjusted odds ratio [OR] 1.53, 95% confidence interval [CI] 1.13-2.09, P=0.007) and 30-day mortality (adjusted hazard ratio [HR] 2.73, 95% CI 1.85-4.02, P<0.001). The KID-ACS score integrates PENK and showed an area under the receiver operating characteristic curve (AUC) of 0.72 (95% CI 0.68-0.76) for in-hospital AKI, and of 0.91 (95% CI 0.87-0.95) for 30-day mortality in the derivation cohort. Upon external validation, KID-ACS achieved similarly high performance for in-hospital AKI (Zurich: AUC 0.73, 95% CI 0.70-0.77; Czechia: AUC 0.75, 95% CI 0.68-0.81; Germany: AUC 0.71, 95% CI 0.55-0.87) and 30-day mortality (UK: AUC 0.87, 95% CI 0.83-0.91; Czechia: AUC 0.91, 95% CI 0.87-0.94; Germany: AUC 0.96, 95% CI 0.92-1.00) outperforming the CA-AKI score and the GRACE 2.0 score, respectively. Circulating PENK offers incremental value for predicting in-hospital AKI and mortality in ACS. The simple 6-item KID-ACS risk score integrates PENK and provides a novel tool for simultaneous assessment of renal and mortality risk in patients with ACS.

Disparate Effects of Stressors on Met-Enkephalin System Parameters and on Plasma Concentrations of Corticosterone in Young Female Chickens.

The effects of stressors were examined on Met-enkephalin-related parameters and plasma concentrations of corticosterone in 14-week-old female chickens. Water deprivation for 24 h was accompanied by a tendency for increased plasma concentration of Met-enkephalin while plasma concentrations of corticosterone were elevated in water-deprived birds. Concentrations of Met-enkephalin were reduced in the anterior pituitary gland and adrenal gland in water-deprived pullets while proenkephalin (PENK) expression was increased in both tissues. There were changes in the plasma concentrations of Met-enkephalin and corticosterone in pullets subjected to either feed withholding or crowding. Concentrations of Met-enkephalin were increased in the anterior pituitary gland but decreased in adrenal glands in pullets subjected to crowding stress. The increase in the plasma concentrations of Met-enkephalin was ablated when the chickens were pretreated with naltrexone. However, naltrexone did not influence either basal or crowding on plasma concentrations of corticosterone. In vitro release of Met-enkephalin from the anterior pituitary or adrenal tissues was depressed in the presence of naltrexone. It was concluded that Met-enkephalin was part of the neuroendocrine response to stress in female chickens. It was concluded that stress influenced the release of both Met-enkephalin and corticosterone, but there was not complete parallelism.

Point-of-Care Serum Proenkephalin as an Early Predictor of Mortality in Patients Presenting to the Emergency Department with Septic Shock.

The aim of the present study is to investigate the prognostic utility of point-of-care (POC)-measured proenkephalin (PENK), a novel biomarker, in terms of predicting in-hospital mortality in patients presenting to the emergency department (ED) with septic shock. Bedside PENK was measured in consecutive patients presenting to the ED with septic shock according to the Sepsis-3 clinical criteria. The association of PENK with inflammatory and routine biomarkers, and its role as a predictor of in-hospital mortality, was examined. Sixty-one patients with septic shock [53% females, median age 83 years (IQR 71-88)] were evaluated. Median (IQR) values of creatinine, plasma lactate, soluble urokinase plasminogen activator receptor (SuPAR), procalcitonin and PENK were 1.7 (1.0-2.9) mg/dL, 3.6 (2.1-6.8) mmol/L, 13.1 (10.0-21.4) ng/mL, 2.06 (0.84-3.49) ng/mL, and 205 (129-425) pmol/L, respectively. LogPENK significantly correlated with LogLactate (rho = 0.369, p = 0.004), LogCreatinine (rho = 0.537, p < 0.001), LogProcalcitonin (rho = 0.557, p < 0.001), and LogSuPAR (rho = 0.327, p = 0.011). During hospitalization, 39/61 (64%) patients died. In a multivariable logistic regression model, logPENK was an independent predictor of in-hospital mortality (OR 11.9, 95% CI: 1.7-84.6, p = 0.013). POC PENK levels measured upon presentation to the ED strongly correlated with metabolic, renal and inflammatory biomarkers, and may serve as a predictor of in-hospital mortality in patients with septic shock.

Increased Cardiovascular Disease Risk in Adult Offspring with Prenatal Opioid Exposure Is Associated with Endogenous Opioid Peptide Dysregulation

Parental drug abuse and dysfunctional households during childhood increase the risk for cardiovascular disease (CVD) later in life. Chronic opioid exposure and opioid use disorder (OUD) are associated with a 2-fold increased risk of CVD and a 16% increase in coronary artery disease. OUD among pregnant women is an understudied area related to the opioid epidemic, causing a 5-fold increase in neonatal opioid withdrawal syndrome (NOWS) incidence. In former studies, we subjected female rats to two models of maternal opioid exposure: 1) morphine sulfate during gestation or 2) fentanyl citrate during preconception and gestation. At birth, female and male opioid-exposed offspring showed normal birth weight compared with vehicle-exposed offspring while displaying NOWS-like somatic withdrawal signs after parturition. As adults, in utero opioid-exposed offspring displayed increased mean arterial pressure, sympathetic activation, and CVD risk factors. Prenatal exposure to opioids has been shown to dysregulate the endogenous opioid peptides (EOPs) and alter behavioral outcomes later in life, but the transplacental effects of opioids on blood pressure regulation remain understudied. Therefore, this study aimed to assess whether adult offspring with prenatal opioid exposure display changes in 1) the expression of the EOP proenkephalin (PENK) in brain regions known to control the sympathetic outflow (Paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM)), heart, kidneys, and liver; 2) the plasma levels of EOPs (PENK, enkephalin, prodynorphin and dynorphin); and 3) the fentanyl plasma clearance (pharmacokinetics). Protein was extracted from tissues for western blot analysis using the primary antibody for PENK (1:1000, Invitrogen). In opioid-exposed offspring, PENK protein expression was reduced in RVLM (0.55±0.06 vs. 0.36±0.01, AU) and PVN (1.56±0.09 vs. 1.08±0.08, AU), showing a ~35% and ~31% reduction, respectively (n=4-5, p&lt;0.05). In the heart, PENK protein expression was not statistically different in opioid-exposed offspring compared with vehicle-exposed offspring. However, in the kidneys (0.72±0.09 vs. 1.16±0.10, AU) and liver (0.40±0.06 vs. 0.60±0.05, AU), PENK protein expression showed a 61% and 50% increase only in male opioid-exposed offspring compared to vehicle-exposed offspring (n=6-8, p&lt;0.05). None of the plasma circulating EOP levels measured by ELISA were affected by prenatal opioid exposure. Fentanyl clearance in plasma (0, 15, 30, 60, 120, 360,1440 mins) following a fentanyl injection (20ug/kg, sc.) was not different between adult vehicle and opioid-exposed offspring, indicating potential pharmacodynamic alterations secondary to prenatal opioid exposure. As EOPs exert inhibitory effects on adrenergic signaling, our data indicate that prenatal exposure to opioids may induce a permanent downregulation of EOPs in the central nervous system and thus contributing to increasing the sympathetic tone and desensitize the acute depressor responses to opioid peptides, suggesting that EOPs may be critical for blood pressure regulation. However, peripheral expression of PENK seems to reflect pathophysiological alterations in different tissues since elevated PENK level is used in clinical settings as a marker to assess the severity of tissue damage in the liver and kidneys. This study was funded by 1013177615 (NRPA-UK), 1013400001 (SUGAR-UK) and 1013171360 (DPNS-UK). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Furosemide stress test to predict acute kidney injury progression in critically ill children.

Furosemide stress test (FST) is a novel functional biomarker for predicting severe acute kidney injury (AKI); however, pediatric studies are limited. Children 3months to 18years of age admitted to the intensive care unit (ICU) of a tertiary care hospital from Nov 2019 to July 2021 were screened and those who developed AKI stage 1 or 2 within 7days of admission underwent FST (intravenous furosemide 1mg/kg). Urine output was measured hourly for the next 6h; a value > 2ml/kg within the first 2h was deemed furosemide responsive. Other biomarkers like plasma neutrophil gelatinase-associated lipocalin (NGAL) and proenkephalin (PENK) were also evaluated. Of the 480 admitted patients, 51 developed AKI stage 1 or 2 within 7days of admission and underwent FST. Nine of these patients were furosemide non-responsive. Thirteen (25.5%) patients (eight of nine from FST non-responsive group) developed stage 3 AKI within 7days of FST, nine (17.6%) of whom (seven from non-responsive group) required kidney support therapy (KST). FST emerged as a good biomarker for predicting stage 3 AKI and need for KST with area-under-the-curve (AUC) being 0.93 ± 0.05 (95% CI 0.84-1.0) and 0.96 ± 0.03 (95% CI 0.9-1.0), respectively. FST outperformed NGAL and PENK in predicting AKI stage 3 and KST; however, the combination did not improve the diagnostic accuracy. Furosemide stress test is a simple, inexpensive, and robust biomarker for predicting stage 3 AKI and KST need in critically ill children. Further research is required to identify the best FST cut-off in children.

The Role of Biomarkers in Diagnosis of Sepsis and Acute Kidney Injury.

Sepsis and acute kidney injury (AKI) are two major public health concerns that contribute significantly to illness and death worldwide. Early diagnosis and prompt treatment are essential for achieving the best possible outcomes. To date, there are no specific clinical, imaging, or biochemical indicators available to diagnose sepsis, and diagnosis of AKI based on the KDIGO criterion has limitations. To improve the diagnostic process for sepsis and AKI, it is essential to continually evolve our understanding of these conditions. Delays in diagnosis and appropriate treatment can have serious consequences. Sepsis and AKI often occur together, and patients with kidney dysfunction are more prone to developing sepsis. Therefore, identifying potential biomarkers for both conditions is crucial. In this review, we talk about the main biomarkers that evolve the diagnostic of sepsis and AKI, namely neutrophil gelatinase-associated lipocalin (NGAL), proenkephalin (PENK), and cell-free DNA.

Research Note: Morphine influences circulating and tissue concentrations of met-enkephalin and proenkephalin (PENK) expression and plasma concentrations of corticosterone in chickens

The effects of the administration of the opioid agonist, morphine, on plasma and tissue concentrations of Met-enkephalin were determined in 14 wk old female chickens. In addition, effects of morphine on proenkephalin (PENK) expression were examined. Plasma concentrations of Met-enkephalin were reduced 10 minutes after morphine administration. Plasma concentrations of peptides that contain Met-enkephalin motifs were decreased 30 minutes after morphine administration. Tissue concentrations of Met-enkephalin tended to be depressed following morphine administration. Adrenal concentrations of PENK peptides containing Met-enkephalin motifs were decreased in chickens challenged with morphine. Expression of PENK in the anterior pituitary gland and adrenal glands were decreased in morphine treated compared to control pullets. In contrast, plasma concentrations of corticosterone were elevated 10 min after morphine treatment. Morphine also induced changes in mu (µ) opioid receptors and delta (δ) opioid receptors in both anterior pituitary tissue and adrenal tissues.

Prostate cancer research: tools, cell types, and molecular targets.

Multiple cancer cell types are found in prostate tumors. They are either luminal-like adenocarcinoma or less luminal-like and more stem-like non-adenocarcinoma and small cell carcinoma. These types are lineage related through differentiation. Loss of cancer differentiation from luminal-like to stem-like is mediated by the activation of stem cell transcription factors (scTF) such as LIN28A, NANOG, POU5F1 and SOX2. scTF expression leads to down-regulation of β2-microglobulin (B2M). Thus, cancer cells can change from the phenotype of differentiated to that of of dedifferentiated in the disease course. In development, epithelial cell differentiation is induced by stromal signaling and cell contact. One of the stromal factors specific to prostate encodes proenkephalin (PENK). PENK can down-regulate scTF and up-regulate B2M in stem-like small cell carcinoma LuCaP 145.1 cells indicative of exit from the stem state and differentiation. In fact, prostate cancer cells can be made to undergo dedifferentiation or reprogramming by scTF transfection and then to differentiate by PENK transfection. Therapies need to be designed for treating the different cancer cell types. Extracellular anterior gradient 2 (eAGR2) is an adenocarcinoma antigen associated with cancer differentiation that can be targeted by antibodies to lyse tumor cells with immune system components. eAGR2 is specific to cancer as normal cells express only the intracellular form (iAGR2). For AGR2-negative stem-like cancer cells, factors like PENK that can target scTF could be effective in differentiation therapy.

Plasma proenkephalin A and incident chronic kidney disease and albuminuria in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort

BackgroundPlasma proenkephalin A (PENK-A) is a precursor of active enkephalins. Higher blood concentrations have been associated with estimated glomerular filtration rate (eGFR) decline in European populations. Due to the significant disparity in incident chronic kidney disease (CKD) between White and Black people, we evaluated the association of PENK-A with incident CKD and other kidney outcomes among a biracial cohort in the U.S.MethodsIn a nested cohort of 4,400 participants among the REasons for Geographic And Racial Differences in Stroke, we determined the association between baseline PENK-A concentration and incident CKD using the creatinine-cystatin C CKD-EPI 2021 equation without race coefficient, significant eGFR decline, and incident albuminuria between baseline and a follow-up visit 9.4 years later. We tested for race and sex interactions. We used inverse probability sampling weights to account for the sampling design.ResultsAt baseline, mean (SD) age was 64 (8) years, 49% were women, and 52% were Black participants. 8.5% developed CKD, 21% experienced ≥ 30% decline in eGFR and 18% developed albuminuria. There was no association between PENK-A and incident CKD and no difference by race or sex. However, higher PENK-A was associated with increased odds of progressive eGFR decline (OR: 1.12; 95% CI 1.00, 1.25). Higher PENK-A concentration was strongly associated with incident albuminuria among patients without diabetes mellitus (OR:1.29; 95% CI 1.09, 1.53).ConclusionWhile PENK-A was not associated with incident CKD, its associations with progression of CKD and incident albuminuria, among patients without diabetes, suggest that it might be a useful tool in the evaluation of kidney disease among White and Black patients.

Effects of hexarelin and isolation stress on the Met-enkephalin system in young lambs

Koziec K., S canes C.G., Z ubel-Łojek J., Gajewska A. 2023. Effects of hexarelin and isolation stress on the Met-enkephalin system in young lambs. Folia Biologica (Kraków) 71: 195-206.Stress stands out as the primary instigator of numerous diseases – ranging from cardiovascular and gastro- intestinal to diabetes and nervous disturbances – in most developed nations. Endogenous opioid peptides (EOP), particularly Met-enkephalin, play a crucial role in mitigating the up-regulation of the hypothalamo- pituitary-adrenal axis during stress responses, consequently reducing the risk of serious diseases. Hexarelin, a synthetic analog of Met-enkephalin, has been predominantly investigated for its impact on growth hormone (GH) release in both human subjects and rodent models. This study was undertaken to evaluate the influence of isolation stress and/or hexarelin administration on various Met-enkephalin-related parameters in a novel animal model – 3-month-old lambs. Four distinct groups were established: a control group, a group intravenously injected with hexarelin, a group subjected to 60 min of isolation stress from the herd, and a group treated with both hexarelin and stress. Blood and hypothalamus samples were collected to analyze cortisol and Met-enkephalin profiles, proenkephalin (PENK) gene expression, Met-enkephalin concentration, in vitro Met-enkephalin secretion, and opioid receptor binding. The findings revealed a significant impact of stress on all assessed parameters. Hexarelin alone led to a decrease in cortisol levels and Met-enkephalin synthesis, release, and receptor binding in the hypothalamus. When administered prior to stress, hexarelin potentiated the responses of opioid parameters to isolation. These results, for the first time, demonstrate that hexarelin interacts with Met-enkephalin, modulating the stress response at both central and peripheral levels in growing lambs. It is suggested that hexarelin plays a crucial role during stress responses; however, further research on its effects should be conducted concurrently with the examination of opioid profiles.

Proenkephalin-A secreted by renal proximal tubules functions as a brake in kidney regeneration

Organ regeneration necessitates precise coordination of accelerators and brakes to restore organ function. However, the mechanisms underlying this intricate molecular crosstalk remain elusive. In this study, the level of proenkephalin-A (PENK-A), expressed by renal proximal tubular epithelial cells, decreases significantly with the loss of renal proximal tubules and increased at the termination phase of zebrafish kidney regeneration. Notably, this change contrasts with the role of hydrogen peroxide (H2O2), which acts as an accelerator in kidney regeneration. Through experiments with penka mutants and pharmaceutical treatments, we demonstrate that PENK-A inhibits H2O2 production in a dose-dependent manner, suggesting its involvement in regulating the rate and termination of regeneration. Furthermore, H2O2 influences the expression of tcf21, a vital factor in the formation of renal progenitor cell aggregates, by remodeling H3K4me3 in renal cells. Overall, our findings highlight the regulatory role of PENK-A as a brake in kidney regeneration.

Placental mesenchymal stem cells-secreted proenkephalin suppresses the p38 MAPK signaling to block hyperproliferation of keloid fibroblasts

BackgroundThanks to their multi-potency and secretory functions, mesenchymal stem cells (MSCs) have long been established as an ideal cell type for skin wound healing and a candidate therapeutic strategy for excessive pathological scarring in the meantime. This study focuses on the effect of placental MSCs (PMSCs) on the activity of keloid fibroblasts (KFs) and the potential involvement of proenkephalin (PENK). MethodsSecretory protein of PMSC that are lowly expressed in KFs were predicted by bioinformatics analyses. The expression of PENK in KFs was detected by RT-qPCR and western blot analysis. PMSCs were co-cultured with KFs and dermal fibroblasts (DFs) to examine their effect on proliferation, migration, invasion, and apoptosis of the distinct cell types. PENK secretion by PMSCs and its uptake by KFs were examined by ELISA, WB, and immunofluorescence staining. Loss-of-functions of PENK and p38-MAPK were induced to examine the activity of KFs in vitro and in mice. ResultsPENK, a secretory protein of PMSCs, was conspicuously downregulated in KFs compared to normal DFs. PMSC stimulation suppressed proliferation, migration, invasion, and resistance to apoptosis of the co-cultured KFs but not DFs, which was ascribed to the upregulation of PENK protein in KFs. PMSCs-secreted PENK suppressed p38 phosphorylation in KFs. The proliferative and aggressive properties of KFs in vitro and the nodule-forming capacity of KFs in vivo were promoted upon PENK downregulation but suppressed by the p38 MAPK inhibitor SB202190. ConclusionThis work unravels that PMSCs-secreted PENK suppresses the p38 MAPK signaling to block hyperproliferation of KFs.

Abstract 030: Perinatal Paradigms Of Opioid Use To Investigate Cardiovascular Disease (CVD) Risk In Adult Offspring

Adversity and dysfunctional households during childhood have been shown to increase systolic blood pressure and overall CVD risk in the long term. A common contributor to dysfunctional households is the parental drug abuse, which transplacental effects acts as a stressor to the developing offspring. Opioid use disorder (OUD) among pregnant women is an understudied area related to the opioid epidemic, causing a 5-fold increase in neonatal opioid withdrawal syndrome (NOWS) incidence. In former studies, we subjected female rats to two models of maternal opioid exposure 1) daily escalating doses of morphine from gestational day 1-19, or 2) fentanyl self-administration during preconception and gestation. Female and male opioid-exposed offspring are smaller throughout the lifespan than vehicle (VEH)-exposed counterparts, displaying NOWS-like somatic withdrawal signs and catch-up growth. Also, in utero opioid-exposed adult offspring displayed sympathetic activation and increased CVD risk factors. Perinatal exposure to opioids has been shown to dysregulate the endogenous opioid peptides (EOP) and alter behavioral outcomes later in life, but the effects on blood pressure regulation remain understudied. Therefore, this study aimed to investigate the expression of proenkephalin (PENK) in brain regions known to control the sympathetic outflow (PVN, RVLM, NTS) and the pressor response to Leu-Enkephalin (100 ug/kg i.p) in adult offspring exposed to VEH or opioids in utero. PENK protein expression in RVLM showed a ~50% reduction in opioid-exposed offspring vs. VEH (p&lt;0.05). As expected, the pressor response to Leu-ENK in conscious VEH-exposed rats showed a ~30% increase in mean arterial pressure from baseline, while the pressor response was blunted in opioid-exposed offspring (12.2±3.7 vs. -4.5±2.1 delta mmHg, n=4-5, p&lt;0.05). As EOP exert inhibitory effects on adrenergic signaling, our data indicate that perinatal exposure to opioids may induce a permanent downregulation of EOP in the central nervous system. Similar to what we reported in vasculature and heart, reduced PENK may contribute to increasing the sympathetic tone and desensitize acute pressor responses to EOP, suggesting that optimal EOP levels may be critical for blood pressure regulation.

Assessing GFR With Proenkephalin

In clinical practice, kidney (dys)function is monitored through creatinine-based estimations of glomerular filtration rate (eGFR: Modification of Diet in Renal Disease [MDRD], Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]). Creatinine is recognized as a late and insensitive biomarker of glomerular filtration rate (GFR). The novel biomarker proenkephalin (PENK) may overcome these limitations, but no PENK-based equation for eGFR is currently available. Therefore, we developed and validated a PENK-based equation to assess GFR. In this international multicenter study in 1354 stable and critically ill patients, GFR was measured (mGFR) through iohexol or iothalamate clearance. A generalized linear model with sigmoidal nonlinear transfer function was used for equation development in the block-randomized development set. Covariates were selected in a data-driven fashion. The novel equation was assessed for bias, precision (mean ± SD), and accuracy (eGFR percentage within ±30% of mGFR, P30) in the validation set and compared with MDRD and CKD-EPI. Median mGFR was 61 [44-81] ml/min per 1.73 m2. In order of importance, PENK, creatinine, and age were included, and sex or race did not improve performance. The PENK-based equation mean ± SD bias of the mGFR was 0.5 ± 15 ml/min per 1.73 m2, significantly less compared with MDRD (8 ± 17, P< 0.001) and 2009 CKD-EPI (5 ± 17, P< 0.001), not reaching statistical significance compared with 2021 CKD-EPI (1.3 ± 16, P= 0.06). The P30 accuracy of the PENK-based equation was 83%, significantly higher compared with MDRD (68%, P< 0.001) and 2009 CKD-EPI (76%, P< 0.001), similar to 2021 CKD-EPI (80%, P= 0.13). Overall, the PENK-based equation to assess eGFR performed better than most creatinine-based equations without using sex or race.

Avian opioid peptides: evolutionary considerations, functional roles and a challenge to address critical questions.

The present review considers the putative hormonal opioid peptides in birds. In birds and all other vertebrates, there are four opioid related genes encoding a series of peptides. These genes are, respectively, proenkephalin (PENK), prodynorphin (PDYN), pronociceptin (PNOC) and proopiomelanocortin (POMC). Proenkephalin (PENK) encodes Met- and Leu-enkephalin together with peptides containing met enkephalin motifs in birds, mammals and reptiles. Proopiomelanocortin (POMC) encodes β endorphin together with adrenocorticotropic hormone (ACTH), and melanocyte stimulating hormone (MSH). Prodynorphin (PDYN) encoding dynorphins A and B with α- and β-neoendorphins together intermediate polypeptides across the vertebrates. Pronociceptin (PNOC) encodes nociceptin together with possibly putative avian nocistatin and a non-opioid peptide derived from the C terminal of pronociceptin. There is a high degree of identity in the sequences of enkephalin peptides, dynorphin-A and B and nociceptin in birds and, to a less extent, across vertebrates. The opioid peptides exert effects related to pain together with other biological actions such as growth/development acting via a series of opioid receptors. What is unclear, particularly in birds, is the biological roles and interactions (additivity, antagonistic and synergistic) for the individual opioid peptides, the processing of the prohormones in different tissues and the physiological relevance of the different peptides and, particularly, of the circulating forms.

Plasma Pro-Enkephalin A and Incident Cognitive Impairment: The Reasons for Geographic and Racial Differences in Stroke Cohort.

Background Cardiovascular disease is a risk factor for cognitive impairment. Evidence links both lower and higher concentration of the circulating opioid pro-enkephalin A (PENK-A) with stroke risk. We studied the association of plasma PENK-A with incident cognitive impairment. Methods and Results REGARDS (Reasons for Geographic and Racial Differences in Stroke) is a prospective cohort study of 30 239 adults enrolled from 2003 to 2007. Baseline PENK-A was measured in a nested case-control study of 462 participants who developed cognitive impairment over 4.7 years, and 556 controls. Logistic regression and spline plots adjusted for confounders estimated odds ratios (ORs) of cognitive impairment by baseline PENK-A. Interaction terms tested for differences in associations by age, sex, and race. Baseline PENK-A was comparable between cases and controls. There were significant differences in the association of PENK-A with cognitive impairment by sex and age (adjusted P=0.003 and 0.06, respectively). In women but not men, spline plots showed that higher and lower PENK-A were associated with decreased odds of cognitive impairment (ORs for 10th and 90th percentiles versus median, 0.65 [95% CI, 0.43-0.96] and 0.64 [95% CI, 0.41-0.99]), with no difference by age. In men ≥65 years of age but not younger men, higher PENK-A was associated with decreased odds for cognitive impairment (OR for fourth versus first quartile 0.47 [95% CI, 0.22-0.99]); this pattern was not confirmed with spline plotting. Conclusions High and low levels of circulating opioid PENK-A were associated with decreased odds of future cognitive impairment in specific subgroups. Additional research is warranted to understand the biology underlying this association and the observed differences by sex.

Urinary Proteins of Female Domestic Dog (Canis familiaris) during Ovarian Cycle.

The presence and identity of non-volatile chemical signals remain elusive in canines. In this study, we aim to evaluate the urinary proteins of female domestic dogs in the estrus and anestrus phases to evidence the presence of non-volatile chemical signals and to elucidate their identities. We collected urine samples from eight female dogs in the estrus and anestrus phases. A total of 240 proteins were identified in the urine samples using liquid chromatography-mass spectrometry (LC-MS analysis). The comparison of the proteins revealed a significant difference between the estrus and anestrus urine. We identified proteins belonging to the lipocalin family of canines (beta-lactoglobulin-1 and beta-lactoglobulin-2, P33685 and P33686, respectively), one of whose function was the transport of pheromones and which was present only in the estrus urine samples. Moreover, proteins such as Clusterin (CLU), Liver-expressed antimicrobial peptide 2 (LEAP2), and Proenkephalin (PENK) were more abundant in the estrus urine when compared to the anestrus urine. LEAP2 was recently described as a ghrelin receptor antagonist and implicated in regulating food intake and body weight in humans and mice. Proenkephalin, a polypeptide hormone cleaved into opioid peptides, was also recognized as a candidate to determine kidney function. As of yet, none of these have played a role in chemical communication. Clusterin, an extracellular chaperone protecting from protein aggregation implicated in stress-induced cell apoptosis, is a plausible candidate in chemical communication, which is a claim that needs to be ascertained further. Data are available via ProteomeXchange with the identifier PXD040418.

Proenkephalin as a Novel Prognostic Marker in Heart Failure Patients: A Systematic Review and Meta-Analysis.

Over the last several years, the use of biomarkers in the diagnosis of patients with heart failure (HF) has skyrocketed. Natriuretic peptides are currently the most widely used biomarker in the diagnosis and prognosis of individuals with HF. Proenkephalin (PENK) activates delta-opioid receptors in cardiac tissue, resulting in a decreased myocardial contractility and heart rate. However, the goal of this meta-analysis is to evaluate the association between the PENK level at the time of admission and prognosis in patients with HF, such as all-cause mortality, rehospitalization, and decreasing renal function. High PENK levels have been associated with a worsened prognosis in patients with HF.