β-Cell insulin secretion is dependent on proper mitochondrial function. Various studies have clearly shown that the Nr4a family of orphan nuclear receptors is essential for fuel utilization and mitochondrial function in liver, muscle, and adipose. Previously, we have demonstrated that overexpression of Nr4a1 or Nr4a3 is sufficient to induce proliferation of pancreatic β-cells. In this study, we examined whether Nr4a expression impacts pancreatic β-cell mitochondrial function. Here, we show that β-cell mitochondrial respiration is dependent on the nuclear receptors Nr4a1 and Nr4a3. Mitochondrial respiration in permeabilized cells was significantly decreased in β-cells lacking Nr4a1 or Nr4a3. Furthermore, respiration rates of intact cells deficient for Nr4a1 or Nr4a3 in the presence of 16 mM glucose resulted in decreased glucose mediated oxygen consumption. Consistent with this reduction in respiration, a significant decrease in glucose-stimulated insulin secretion rates is observed with deletion of Nr4a1 or Nr4a3. Interestingly, the changes in respiration and insulin secretion occur without a reduction in mitochondrial content, suggesting decreased mitochondrial function. We establish that knockdown of Nr4a1 and Nr4a3 results in decreased expression of the mitochondrial dehydrogenase subunits Idh3g and Sdhb. We demonstrate that loss of Nr4a1 and Nr4a3 impedes production of ATP and ultimately inhibits glucose-stimulated insulin secretion. These data demonstrate for the first time that the orphan nuclear receptors Nr4a1 and Nr4a3 are critical for β-cell mitochondrial function and insulin secretion.
BACKGROUND
The Affordable Care Act (ACA) and the appropriate use criteria (AUC) for Mohs micrographic surgery (MMS) had the potential to increase utilization rates of MMS for indicated skin cancers, but it is unknown whether this has occurred.
OBJECTIVE
To determine whether rates of MMS utilization for head and neck melanoma in situ (MIS) and rare cutaneous tumors (RCTs) increased after the implementation of the ACA and AUC publication.
MATERIALS AND METHODS
Retrospective review using data from the SEER database. Melanoma in situ and RCT tumor cases from before and after the ACA and AUC publication were compared.
RESULTS
Twenty-four thousand six hundred seventy-eight cases were analyzed. Mohs micrographic surgery utilization for MIS decreased from 13.9% before the ACA to 12.3% after the ACA (odds ratio 0.87; p = .012). There was no significant change in MMS utilization for MIS after publication of the AUC. There was also no significant change in MMS utilization for treatment of RCT after the ACA or AUC publication. Stratification of patients into age groups younger or older than 65 years did not change utilization rates.
CONCLUSION
Rates of MMS for treatment of MIS and RCT have not increased since the advent of the ACA or AUC. This finding highlights the need for continued efforts to improve access to MMS and to increase education of its utility in treating skin cancer.
A 68-year-old man presented for treatment of a 5.0 by 3.0-cm recurrent infiltrative basal cell carcinoma involving the right nasal sidewall extending to the glabella. Tumor extirpation required 3 stages of Mohs micrographic surgery, resulting in a surgical defect measuring 7.0 by 5.0 cm involving 9 cosmetic subunits of the central face, including the forehead, glabella, nasal dorsum, right nasal sidewall, right infraorbital cheek, right upper eyelid, right eyebrow, and right and left medial canthi (Figure 1).How would you repair this defect?
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