title: A bioengineered hydrogel system enables targeted and sustained intramyocardial delivery of neuregulin, activating the cardiomyocyte cell cycle and enhancing ventricular function in a murine model of ischemic cardiomyopathy.
abstract: BACKGROUND
  Neuregulin-1β (NRG) is a member of the epidermal growth factor family possessing a critical role in cardiomyocyte development and proliferation. Systemic administration of NRG demonstrated efficacy in cardiomyopathy animal models, leading to clinical trials using daily NRG infusions. This approach is hindered by requiring daily infusions and off-target exposure. Therefore, this study aimed to encapsulate NRG in a hydrogel to be directly delivered to the myocardium, accomplishing sustained localized NRG delivery.
  
  
  RESULTS
  NRG was encapsulated in hydrogel, and release over 14 days was confirmed by ELISA in vitro. Sprague-Dawley rats were used for cardiomyocyte isolation. Cells were stimulated by PBS, NRG, hydrogel, or NRG-hydrogel (NRG-HG) and evaluated for proliferation. Cardiomyocytes demonstrated EdU (5-ethynyl-2'-deoxyuridine) and phosphorylated histone H3 positivity in the NRG-HG group only. For in vivo studies, 2-month-old mice (n=60) underwent left anterior descending coronary artery ligation and were randomized to the 4 treatment groups mentioned. Only NRG-HG-treated mice demonstrated phosphorylated histone H3 and Ki67 positivity along with decreased caspase-3 activity compared with all controls. NRG was detected in myocardium 6 days after injection without evidence of off-target exposure in NRG-HG animals. At 2 weeks, the NRG-HG group exhibited enhanced left ventricular ejection fraction, decreased left ventricular area, and augmented borderzone thickness.
  
  
  CONCLUSIONS
  Targeted and sustained delivery of NRG directly to the myocardial borderzone augments cardiomyocyte mitotic activity, decreases apoptosis, and greatly enhances left ventricular function in a model of ischemic cardiomyopathy. This novel approach to NRG administration avoids off-target exposure and represents a clinically translatable strategy in myocardial regenerative therapeutics.
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Cohen
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Brendan P
authors.initials: BP
authors.lastname: Purcell
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: John W
authors.initials: JW
authors.lastname: MacArthur
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Anbin
authors.initials: A
authors.lastname: Mu
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shudo
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Jay B
authors.initials: JB
authors.lastname: Patel
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Brusalis
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Alen
authors.initials: A
authors.lastname: Trubelja
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Fairman
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Bryan B
authors.initials: BB
authors.lastname: Edwards
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Mollie S
authors.initials: MS
authors.lastname: Davis
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: George
authors.initials: G
authors.lastname: Hung
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: William
authors.initials: W
authors.lastname: Hiesinger
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Pavan
authors.initials: P
authors.lastname: Atluri
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Margulies
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Burdick
authors.affiliation: From the Department of Cardiothoracic Surgery, Stanford University, CA (J.E.C., J.W.M., Y.S., J.B.P., B.B.E., Y.J.W.); and Departments of Surgery, Division of Cardiovascular Surgery (J.E.C., J.W.M., C.M.B., A.T., A.S.F., G.H., W.H., P.A.), Bioengineering (B.P.P., M.S.D., J.A.B.), and Cardiology (A.M., K.B.M.), University of Pennsylvania, Philadelphia. joswoo@stanford.edu.
authors.forename: Y Joseph
authors.initials: YJ
authors.lastname: Woo
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D057005:Bioengineering / Q000379:methods*; D009202:Cardiomyopathies / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D049109:Cell Proliferation; D002478:Cells, Cultured; D003692:Delayed-Action Preparations; D004195:Disease Models, Animal; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D007150:Immunohistochemistry; D007267:Injections; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D017202:Myocardial Ischemia / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D020890:Neuregulin-1 / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016277:Ventricular Function, Left / Q000187:drug effects*
chemical_list: D003692:Delayed-Action Preparations; D020890:Neuregulin-1; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
keywords: heart failure; ischemia; molecular biology; muscle cells; myocardial infarction