Photocrosslinkable methacrylated gelatin hydrogel as a cell-friendly injectable delivery system for chlorhexidine in regenerative endodontics.

OBJECTIVES: This work sought to formulate photocrosslinkable chlorhexidine (CHX)-laden methacrylated gelatin (CHX/GelMA) hydrogels with broad spectrum of action against endodontic pathogens as a clinically viable cell-friendly disinfection therapy prior to regenerative endodontics procedures. METHODS: CHX/GelMA hydrogel formulations were successfully synthesized using CHX concentrations between 0.12 % and 5 % w/v. Hydrogel microstructure was evaluated by scanning electron microscopy (SEM). Swelling and enzymatic degradation were assessed to determine microenvironmental effects. Compression test was performed to investigate the influence of CHX incorporation on the hydrogels' biomechanics. The antimicrobial and anti-biofilm potential of the formulated hydrogels were assessed using agar diffusion assays and a microcosms biofilm model, respectively. The cytocompatibility was evaluated by exposing stem cells from human exfoliated deciduous teeth (SHEDs) to hydrogel extracts (i.e., leachable byproducts obtained from overtime hydrogel incubation in phosphate buffer saline). The data were analyzed using One- and Two-way ANOVA and Tukey's test (α = 0.05). RESULTS: CHX/GelMA hydrogels were effectively prepared. NMR spectroscopy confirmed the incorporation of CHX into GelMA. The addition of CHX did not change the micromorphology (pore size) nor the swelling profile (p > 0.05). CHX incorporation reduced the degradation rate of the hydrogels (p < 0.001); whereas, it contributed to increased compressive modulus (p < 0.05). Regarding the antimicrobial properties, the incorporation of CHX showed a statistically significant decrease in the number of bacteria colonies at 0.12 % and 0.5 % concentration (p < 0.001) and completely inhibited the growth of biofilm at concentration levels 1 %, 2 %, and 5 %. Meanwhile, the addition of CHX, regardless of the concentration, did not lead to cell toxicity, as cell viability values were above 70 %. SIGNIFICANCE: The addition of CHX into GelMA showed significant antimicrobial action against the pathogens tested, even at low concentrations, with the potential to be used as a cell-friendly injectable drug delivery system for root canal disinfection prior to regenerative endodontics.

Noncompaction Cardiomyopathy and Stroke: Case Report and Literature Review.

BACKGROUND: To describe a rare case of isolated noncompaction cardiomyopathy and stroke and to review the medical literature on noncompaction cardiomyopathy. METHODS: Retrospective chart review of the case was performed. Extensive literature review on etiology, clinical presentation, diagnosis, and management of noncompaction cardiomyopathy was also performed. RESULTS: Our patient is a healthy 20-year-old woman who presented with sudden onset left face and arm weakness and hypesthesia. Magnetic resonance imaging (MRI) brain showed right middle cerebral artery (MCA) infarct. Magnetic resonance angiography head showed right MCA artery (M2) cutoff. MRI neck was nonsignificant. Echocardiogram was suggestive of noncompaction of left ventricle. Cardiac MRI confirmed the noncompaction of the left ventricle myocardium, which was thought to be the etiology of stroke. Patient was started on anticoagulation for secondary stroke prevention. CONCLUSIONS: Isolated left ventricular noncompaction cardiomyopathy (LVNC) is a rare form of primary genetic cardiomyopathy, which occurs because of the arrest of the process of compaction of ventricular myocardium during embryogenesis. Noncompaction cardiomyopathy is usually associated with other primary cardiac structural abnormalities like dysfunctional cardiac valves. In isolated noncompaction cardiomyopathy, there are no other primary cardiac structural abnormalities. The most common clinical features seen in LVNC include left ventricular systolic dysfunction, congestive heart failure, arrhythmias, and cardiac embolic events theorized to result from thrombus formation within the intertrabecular recesses. As it is a rare disease, evidence-based recommendations for preventing thromboembolic events in isolated left ventricular noncompaction have not been established.

miRNA-141 is a novel regulator of BMP-2-mediated calcification in aortic stenosis.

OBJECTIVE: Bone morphogenetic protein-2 (BMP-2) is a major regulator of aortic valve calcification. MicroRNAs (miRNAs) are essential post-transcriptional modulators of gene expression and miRNA-141 is a known repressor of BMP-2-mediated osteogenesis. We hypothesized that miRNA-141 is a key regulator of aortic valve calcification. METHODS: Porcine valvular interstitial cells were isolated, transfected with miRNA-141 or control, and stimulated with transforming growth factor-ß. The BMP-2, extracellular signal-regulated kinase 1/2, and runt-related transcription factor 2 levels were determined by immunoblotting and reverse transcriptase polymerase chain reaction. To determine the role of miRNA-141 in bicuspid aortic valve disease, human bicuspid (n = 19) and tricuspid (n = 17) aortic valve leaflets obtained intraoperatively were submitted for GenoExplorer human microRNA array, immunoblotting, and histologic and immunohistochemical analyses. RESULTS: Stimulation of porcine aortic valvular interstitial cells with transforming growth factor-ß induced morphologic alterations consistent with myofibroblastic transformation, BMP-2 signaling, and calcification. Transfection with miRNA-141 restored transforming growth factor-ß-induced valvular interstitial cell activation, BMP-2 signaling, and alkaline phosphatase activity (3.55 ± 0.18 vs 4.01 ± 0.21, P < .05), suggesting upstream regulation by miRNA-141. miRNA microarray demonstrated differential expression of 35 of 1583 miRNA sequences in the bicuspid versus tricuspid aortic valve leaflets, with a 14.5-fold decrease in miRNA-141 in the bicuspid versus tricuspid leaflets (P < .05). This was associated with significantly increased BMP-2 protein expression in bicuspid aortic valve compared with the tricuspid aortic valve leaflets (P < .001). CONCLUSIONS: We report a completely novel role of miRNA-141 as a regulator of BMP-2-dependent aortic valvular calcification and demonstrate marked attenuation of miRNA-141 expression in patients with bicuspid aortic valve-associated aortic stenosis. Therapeutic targeting of miRNA-141 could serve as a novel strategy to limit progressive calcification in aortic stenosis.