Abstract 16015: Exosome-mediated Reversal of Duchenne Cardiomyopathy

Duchenne muscular dystrophy, a crippling genetic disease leading to premature death, affects the heart as well as skeletal muscle. Indeed, cardiomyopathy is the leading cause of death in Duchenne patients. There are no approved treatments for the cardiomyopathy, and novel Duchenne-specific experimental approaches such as exon skipping do not benefit the heart. Here we demonstrate that cardiosphere-derived cells (CDCs), which are in advanced clinical testing for therapeutic regeneration after myocardial infarction, reverse the key pathophysiological hallmarks of Duchenne cardiomyopathy (oxidative stress, inflammation, fibrosis and mitochondrial dysfunction) in mdx mice. Exosomes secreted by human CDCs reproduce the benefits of CDCs in mdx mice, and reverse mitochondrial dysfunction in human Duchenne cardiomyocytes. Both CDCs and their exosomes improve heart function in mdx mice (P<0.05); a single injection of CDCs suffices to increase maximal exercise capacity and improve survival (P<0.005). Delivery of a microRNA enriched in CDC exosomes, miR 148a, mimics key effects of CDCs and CDC exosomes. Thus, CDCs effectively treat Duchenne cardiomyopathy, via exosome-mediated transfer of signaling molecules including miR 148a. The present findings motivate clinical testing of CDCs in patients with Duchenne cardiomyopathy.

Heterotopic ossification in rehabilitation patients who have had internal fixation of an acetabular fracture

High-energy trauma patients often have multiple injuries and are frequently seen by a physiatrist following their acute care. Acetabular fractures are common in this patient population. Following surgical treatment of acetabular fractures, a very high incidence of heterotopic ossification can occur. We describe 94 patients who underwent posterior surgical fixation of an acetabular fracture. Of these, 87 received heterotopic ossification prophylaxis in the form of irradiation or indomethacin; 5 did not receive prophylaxis. Seven of the 45 patients who were initially started on indomethacin had their medication discontinued for various reasons. Of the 12 patients who did not receive adequate prophylaxis, 5 developed disabling heterotopic ossification. We present our experience with this patient population, and we discuss the importance of adequate prophylaxis for heterotopic ossification.

Anesthetic efficacy of the periodontal ligament injection after an inferior alveolar nerve block

The purpose of this study was to determine the contribution of the periodontal ligament injection (PDL) to the inferior aveolar nerve (IAN) block in human first molars. Using a repeated-measures design, 40 subjects randomly received a combination IAN block and PDL injections of the first molar using 2% lidocaine with 1:100,000 epinephrine and a combination IAN block and mock PDL injections (needle penetration only) at two successive appointments. The first molar and adjacent teeth, and contralateral canine (positive and negative controls) were blindly tested with an Analytic Technology pulp tester at 2-min cycles for 60 min. Profound anesthesia was defined as no subject response at an 80 reading. One hundred percent of the subjects had lip numbness with the IAN block. When the combination IAN/PDL injections were compared with the IAN block, the incidence of successful pulpal anesthesia (80 reading) was significantly greater for the combination injections through the first 23 min of pulp testing. However, after 23 min, there was no increase in anesthetic success by adding the PDL to the IAN injection. We concluded that adding the PDL injection to an IAN block increased the incidence of pulpal anesthesia for the first 23 min in the first molar.

Hydromorphone and hydrocodone interference in GC/MS assays for morphine and codeine

The specificity of a GC/MS assay of morphine and codeine was examined with particular regard to the potential interference due to hydromorphone and hydrocodone, compounds that cross-react extensively in opiate screening tests. A GC/MS method with solid-phase extraction and acetylation or trimethylsilylation was used. The equilibrium between keto and enol forms of the potential interferents was evaluated. Sodium borohydride was tried as a means for converting potential interferents into products that are more clearly separated from morphine and codeine. It was found that borohydride reduction proceeded easily and led to products that could be distinguished from morphine and codeine. Moreover, the quantitation of morphine in the presence of hydromorphone was improved if the borohydride step was included in the analysis.