Implementation of a Health Literacy Universal Toolkit to Improve Postdischarge Care at an Urban Trauma Center.

TOPIC: Low health literacy impacts the financial burden of hospitals up to $238 billion annually. A trauma center located on the East Coast implemented a Transitional Care Management (TCM) model targeting individuals at risk for readmission, but not every patient receives this service. PURPOSE: A gap analysis of the facility's discharge process identified a deficit in the formal evaluation of health literacy upon discharge. The purpose of this project was to implement a Health Literacy Universal Toolkit to assess and improve medication education for low literacy patients. Included in the toolkit were the Rapid Estimate of Adult Literacy in Medicine Short Form (REALM-SF), an evidence-based health literacy screening tool, and 2 interventions, additional education on their inpatient or discharge medication list, and a Brown Bag Medicine Review of medications at a postdischarge clinic appointment. CONCLUSION: Seventy-one patients were screened using the REALM-SF. Sixty-two percent (n = 44) of patients scored at a high school reading level, 30% (n = 21) scored at a seventh- to eighth-grade reading level, and 8% (n = 6) scored at or below a sixth-grade reading level. Eight percent of patients scored as having low health literacy, 30% scored as having marginal health literacy, and 62% scored as having adequate health literacy. Twenty patients received additional medication education with My Medicines Form or a Brown Bag Medicine Review. KEY POINTS: Regardless of literacy level, patients appreciated the additional medication education interventions. Health care providers should observe universal health literacy precautions regardless of literacy level.

Chemical probing of the human sirtuin 5 active site reveals its substrate acyl specificity and peptide-based inhibitors.

Sirtuins are NAD(+)-dependent deacetylases acting as sensors in metabolic pathways and stress response. In mammals there are seven isoforms. The mitochondrial sirtuin 5 is a weak deacetylase but a very efficient demalonylase and desuccinylase; however, its substrate acyl specificity has not been systematically analyzed. Herein, we investigated a carbamoyl phosphate synthetase 1 derived peptide substrate and modified the lysine side chain systematically to determine the acyl specificity of Sirt5. From that point we designed six potent peptide-based inhibitors that interact with the NAD(+) binding pocket. To characterize the interaction details causing the different substrate and inhibition properties we report several X-ray crystal structures of Sirt5 complexed with these peptides. Our results reveal the Sirt5 acyl selectivity and its molecular basis and enable the design of inhibitors for Sirt5.

Potent and Selective Inhibitors of Human Sirtuin 5.

Sirtuins are protein deacylases that regulate metabolism and stress responses and are implicated in aging-related diseases. Modulators of the human sirtuins Sirt1-7 are sought as chemical tools and potential therapeutics, e.g., for cancer. Selective and potent inhibitors are available for Sirt2, but selective inhibitors for Sirt5 with Ki values in the low nanomolar range are lacking. We synthesized and screened 3-arylthiosuccinylated and 3-benzylthiosuccinylated peptide derivatives yielding Sirt5 inhibitors with low-nanomolar Ki values. A biotinylated derivative with this scaffold represents an affinity probe for human Sirt5 that is able to selectively extract this enzyme out of complex biological samples like cell lysates. Crystal structures of Sirt5/inhibitor complexes reveal that the compounds bind in an unexpected manner to the active site of Sirt5.

SIRT5 regulation of ammonia-induced autophagy and mitophagy.

In liver the mitochondrial sirtuin, SIRT5, controls ammonia detoxification by regulating CPS1, the first enzyme of the urea cycle. However, while SIRT5 is ubiquitously expressed, urea cycle and CPS1 are only present in the liver and, to a minor extent, in the kidney. To address the possibility that SIRT5 is involved in ammonia production also in nonliver cells, clones of human breast cancer cell lines MDA-MB-231 and mouse myoblast C2C12, overexpressing or silenced for SIRT5 were produced. Our results show that ammonia production increased in SIRT5-silenced and decreased in SIRT5-overexpressing cells. We also obtained the same ammonia increase when using a new specific inhibitor of SIRT5 called MC3482. SIRT5 regulates ammonia production by controlling glutamine metabolism. In fact, in the mitochondria, glutamine is transformed in glutamate by the enzyme glutaminase, a reaction producing ammonia. We found that SIRT5 and glutaminase coimmunoprecipitated and that SIRT5 inhibition resulted in an increased succinylation of glutaminase. We next determined that autophagy and mitophagy were increased by ammonia by measuring autophagic proteolysis of long-lived proteins, increase of autophagy markers MAP1LC3B, GABARAP, and GABARAPL2, mitophagy markers BNIP3 and the PINK1-PARK2 system as well as mitochondrial morphology and dynamics. We observed that autophagy and mitophagy increased in SIRT5-silenced cells and in WT cells treated with MC3482 and decreased in SIRT5-overexpressing cells. Moreover, glutaminase inhibition or glutamine withdrawal completely prevented autophagy. In conclusion we propose that the role of SIRT5 in nonliver cells is to regulate ammonia production and ammonia-induced autophagy by regulating glutamine metabolism.