Targeting Myofibroblasts as a Treatment Modality for Dupuytren Disease.

PURPOSE: Currently, no treatment corrects the contractile nature of Dupuytren myofibroblasts (DMFs) or prevents recurrence following surgery. Antifibrotic and proadipogenic growth factors are released when adipose-derived stem cells (ASCs) are cultured with platelet-rich plasma (PRP), a platelet concentration from whole blood. Reprograming myofibroblasts into adipocytes via growth factors is proposed as a powerful potential tool to target fibrosis. We aimed to assess whether the combination of ASCs and PRP reprograms DMFs into adipocytes in vitro and alters their contractile nature in vivo. METHODS: Normal human dermal fibroblasts (NHDFs) and DMFs from Dupuytren patients were isolated and cocultured with ASCs and PRP either alone or together. Adipocytes were detected by Oil Red O and perilipin staining. DMFs and NHDFs were transplanted into the forepaws of rats (Rowett Nude [rnu/rnu]) and treated with saline, PRP+ASCs, or collagenase Clostridium histolyticum (clinical comparison) 2 months later. After 2 weeks, the tissue was harvested and subjected to Masson trichrome staining, and collagen I and III and alpha-smooth muscle actin detection by immunohistochemistry. RESULTS: Myofibroblasts transform into adipocytes upon coculture with PRP+ASCs. DMFs show increased alpha-smooth muscle actin expression in vivo compared with NHDFs, which is significantly decreased after PRP+ASCs and collagenase Clostridium histolyticum treatments. DMFs induce collagen I and III expressions in rat paws compared with NHDFs, with a type III to I ratio increase. Treatment with PRP+ASC reduced the ratio, but collagenase Clostridium histolyticum did not. CONCLUSIONS: Treating DMFs with PRP+ASCs provides factors that induce myofibroblast to adipocyte transformation. This treatment reduces the contractile phenotype and fibrosis markers in vivo. Future studies should detail the mechanism of this conversion. CLINICAL RELEVANCE: The combination of PRP and ASCs to induce the differentiation of DMFs into adipocytes may serve to limit surgery to a percutaneous contracture release and biological injection, rather than a moderate or radical fasciectomy, and reduce the recurrence of Dupuytren contracture.

Nicotine e-cigarette vapor inhalation and self-administration in a rodent model: Sex- and nicotine delivery-specific effects on metabolism and behavior.

E-cigarettes, which deliver vaporized nicotine, have dramatically risen in popularity in recent years, despite many unanswered questions about safety, efficacy in reducing dependence, and overall impact on public health. Other factors, such as sex, also play an important role in determining behavioral and neurochemical responses to drugs of abuse. In these studies, we sought to develop a protocol for vaporized e-cigarette nicotine self-administration in rats, as a foundation to better understand the differing effects of nicotine exposure routes on behavior and physiological function. We report a novel method that elicits robust nicotine vapor self-administration in male and female rats. Our findings indicate that 5-mg/ml nicotine vape solution provides a high level of consistency in lever-pressing behavior for both males and females. Moreover, in male rats, we find that such e-cigarette nicotine vapor induces similar blood levels of nicotine's main metabolite, cotinine, as that found with intravenous nicotine self-administration. Therefore, the breathing pattern during vapor exposure in males leads to similar levels of titrated nicotine intake as with intravenous nicotine self-administration. Interestingly, a differential effect was found in the females, in which the same conditions of vapor exposure led to decreased cotinine levels with vapor compared to intravenous self-administration. Finally, differences in nicotine-mediated locomotion provide further support of the physiological effects of e-cigarette vapor inhalation. Taken together, our findings reveal important sex differences in nicotine intake based on the route of exposure, and we further establish a protocol for nicotine vapor self-administration in rats.

The Novel CYP2A6 Inhibitor, DLCI-1, Decreases Nicotine Self-Administration in Mice.

During tobacco and e-cigarette use, nicotine is mainly metabolized in the human liver by cytochrome P450 2A6 (CYP2A6). Given that a slower CYP2A6 metabolism has been associated with less vulnerability to develop nicotine dependence, the current studies sought to validate a novel CYP2A6 inhibitor, (5-(4-ethylpyridin-3-yl)thiophen-2-yl)methanamine (DLCI-1), for its effects on intravenous nicotine self-administration. Male and female mice were trained to self-administer nicotine across daily sessions. Once stable responding was achieved, DLCI-1 or vehicle control was administered prior to nicotine sessions. We found that the lower 25 mg/kg and moderate 50 mg/kg doses of DLCI-1 induced a significant decrease in nicotine intake for both males and females. DLCI-1 was further shown to be more effective than a moderate 1 mg/kg dose of bupropion on reducing nicotine intake and did not exert the adverse behavioral effects found with a high 75 mg/kg dose of bupropion. Although mice treated with DLCI-1 self-administered significantly less nicotine, similar nicotine-mediated behavioral effects on locomotion were observed. Together, along with the analysis of nicotine metabolites during self-administration, these findings support the contention that blocking hepatic nicotine metabolism would allow for similar activation of nicotinic acetylcholine receptors at lower nicotine doses. Moreover, these effects of DLCI-1 were specific to nicotine self-administration, as DLCI-1 did not result in any behavioral changes during food self-administration. Taken together, these studies validate DLCI-1 as a novel compound to decrease nicotine consumption, which may thereby promote tobacco and nicotine product cessation. SIGNIFICANCE STATEMENT: Current pharmacological approaches for nicotine and tobacco cessation have only been able to achieve limited efficaciousness in promoting long-term abstinence. In this work, we characterize the effects of a novel compound, (5-(4-ethylpyridin-3-yl)thiophen-2-yl)methanamine (DLCI-1), which inhibits the main enzyme that metabolizes nicotine, and we report a significant decrease in intravenous nicotine self-administration in male and female mice, supporting the potential of DLCI-1 as a novel tobacco cessation pharmacotherapeutic.