Diesel Exhaust Particle Exposure Compromises Alveolar Macrophage Mitochondrial Bioenergetics.

Diesel exhaust particles (DEPs) are known pathogenic pollutants that constitute a significant quantity of air pollution. Given the ubiquitous presence of macrophages throughout the body, including the lungs, as well as their critical role in tissue and organismal metabolic function, we sought to determine the effect of DEP exposure on macrophage mitochondrial function. Following daily DEP exposure in mice, pulmonary macrophages were isolated for mitochondrial analyses, revealing reduced respiration rates and dramatically elevated H2O2 levels. Serum ceramides and inflammatory cytokines were increased. To determine the degree to which the changes in mitochondrial function in macrophages were not dependent on any cross-cell communication, primary pulmonary murine macrophages were used to replicate the DEP exposure in a cell culture model. We observed similar changes as seen in pulmonary macrophages, namely diminished mitochondrial respiration, but increased H2O2 production. Interestingly, when treated with myriocin to inhibit ceramide biosynthesis, these DEP-induced mitochondrial changes were mitigated. Altogether, these data suggest that DEP exposure may compromise macrophage mitochondrial and whole-body function via pathologic alterations in macrophage ceramide metabolism.

Insulin selectively reduces mitochondrial uncoupling in brown adipose tissue in mice.

The purpose of the present study was to determine the effects of prolonged hyperinsulinemia on mitochondrial respiration and uncoupling in distinct adipose tissue depots. Sixteen-week-old male mice were injected daily with placebo or insulin to induce an artificial hyperinsulinemia for 28 days. Following the treatment period, mitochondrial respiration and degree of uncoupling were determined in permeabilized perirenal, inguinal, and interscapular adipose tissue. White adipose tissue (WAT) mitochondria (inguinal and perirenal) respire at substantially lower rates compared with brown adipose tissue (BAT). Insulin treatment resulted in a significant reduction in mitochondrial respiration in inguinal WAT (iWAT) and interscapular BAT (iBAT), but not in perirenal WAT (pWAT). Furthermore, these changes were accompanied by an insulin-induced reduction in UCP-1 (uncoupling protein 1) and PGC-1α in iWAT and iBAT only, but not in pWAT or skeletal muscle. Compared with adipose tissue mitochondria in placebo conditions, adipose tissue from hyperinsulinemic mice manifested a site-specific reduction in mitochondrial respiration probably as a result of reduced uncoupling. These results may help explain weight gain so commonly seen with insulin treatment in type 2 diabetes mellitus.

LPS from P. gingivalis Negatively Alters Gingival Cell Mitochondrial Bioenergetics.

OBJECTIVE: Oral inflammatory pathologies are linked to increased oxidative stress, thereby partly explaining their relevance in the etiology of systemic disorders. The purpose of this work was to determine the degree to which LPS from Porphyromonas gingivalis, the primary pathogen related to oral inflammation, altered gingival mitochondrial function and reactive oxygen species generation. METHODS: Human gingival fibroblast (HGF-1) cells were treated with lipopolysaccharide of P. gingivalis. Mitochondrial function was determined via high-resolution respirometry. P GINGIVALIS: Mitochondrial function was determined via high-resolution respirometry. RESULTS: LPS-treated HGF-1 cells had significantly higher mitochondrial complex IV and higher rates of mitochondrial respiration. However, this failed to translate into greater ATP production, as ATP production was paradoxically diminished with LPS treatment. Nevertheless, production of the reactive H2O2 was elevated with LPS treatment. CONCLUSIONS: LPS elicits an increase in gingival cell mitochondria content, with a subsequent increase in reactive oxygen species production (i.e., H2O2), despite a paradoxical reduction in ATP generation. These findings provide an insight into the nature of oxidative stress in oral inflammatory pathologies.

High-Mobility Group Box 1 Disrupts Metabolic Function with Cigarette Smoke Exposure in a Ceramide-Dependent Manner.

We have previously found that cigarette smoke disrupts metabolic function, in part, by increasing muscle ceramide accrual. To further our understanding of this, we sought to determine the role of the cytokine high-mobility group box 1 (HMGB1), which is increased with smoke exposure, in smoke-induced muscle metabolic perturbations. To test this theory, we determined HMGB1 from lungs of human smokers, as well as from lung cells from mice exposed to cigarette smoke. We also treated cells and mice directly with HMGB1, in the presence or absence of myriocin, an inhibitor of serine palmitoyltransferase, the rate-limiting enzyme in ceramide biosynthesis. Outcomes included assessments of insulin resistance and muscle mitochondrial function. HMGB1 was significantly increased in both human lungs and rodent alveolar macrophages. Further testing revealed that HMGB1 treatment elicited a widespread increase in ceramide species and reduction in myotube mitochondrial respiration, an increase in reactive oxygen species, and reduced insulin-stimulated Akt phosphorylation. Inhibition of ceramide biosynthesis with myriocin was protective. In mice, by comparing treatments of HMGB1 injections with or without myriocin, we found that HMGB1 injections resulted in increased muscle ceramides, especially C16 and C24, which were necessary for reduced muscle mitochondrial respiration and compromised insulin and glucose tolerance. In conclusion, HMGB1 may be a necessary intermediate in the ceramide-dependent metabolic consequences of cigarette smoke exposure.

Comparative effectiveness research in practice: the Drug Effectiveness Review Project experience.

AIM: Assess the effect of the Drug Effectiveness Review Project's comparative effectiveness research findings on prescribing behavior independently and in conjunction with a Medicaid preferred drug list. METHOD: We queried prescription drug claims and enrollment information from the 2001-2008 Medicaid Analytic eXtract and Medicaid Statistical Information System for 17 states using a Wilcoxon signed rank test design to evaluate the effects of the Drug Effectiveness Review Project's report release and preferred drug list implementation on ACE inhibitor prescribing behavior at a state level. The primary outcome of interest was the percentage of ACE inhibitor prescriptions that are defined as 'differentiated' based on the content of the Drug Effectiveness Research Program report. RESULTS: The use of differentiated ACE inhibitors increased significantly in states that participated in the Drug Effectiveness Research Program and subsequently implemented a preferred drug list (p < 0.05, one-tailed). However, there was no significant change in utilization in nonparticipating states or in states that participated but did not subsequently implement a preferred drug list. CONCLUSION: Although the publication of comparative effectiveness research findings may not directly influence practice, a preferred drug list can align utilization with clinical evidence. The states that participate in the Drug Effectiveness Review Project and use preferred drug lists have greater utilization of higher quality drugs, making the combination an effective strategy to translate comparative effectiveness research into practice.

Chart-confirmed guillain-barre syndrome after 2009 H1N1 influenza vaccination among the Medicare population, 2009-2010.

Given the increased risk of Guillain-Barré Syndrome (GBS) found with the 1976 swine influenza vaccine, both active surveillance and end-of-season analyses on chart-confirmed cases were performed across multiple US vaccine safety monitoring systems, including the Medicare system, to evaluate the association of GBS after 2009 monovalent H1N1 influenza vaccination. Medically reviewed cases consisted of H1N1-vaccinated Medicare beneficiaries who were hospitalized for GBS. These cases were then classified by using Brighton Collaboration diagnostic criteria. Thirty-one persons had Brighton level 1, 2, or 3 GBS or Fisher Syndrome, with symptom onset 1-119 days after vaccination. Self-controlled risk interval analyses estimated GBS risk within the 6-week period immediately following H1N1 vaccination compared with a later control period, with additional adjustment for seasonality. Our results showed an elevated risk of GBS with 2009 monovalent H1N1 vaccination (incidence rate ratio = 2.41, 95% confidence interval: 1.14, 5.11; attributable risk = 2.84 per million doses administered, 95% confidence interval: 0.21, 5.48). This observed risk was slightly higher than that seen with previous seasonal influenza vaccines; however, additional results that used a stricter case definition (Brighton level 1 or 2) were not statistically significant, and our ability to account for preceding respiratory/gastrointestinal illness was limited. Furthermore, the observed risk was substantially lower than that seen with the 1976 swine influenza vaccine.

Surveillance for Guillain-Barré syndrome after influenza vaccination among the Medicare population, 2009-2010.

OBJECTIVES: We implemented active surveillance for Guillain-Barré syndrome (GBS) following seasonal or H1N1 influenza vaccination among the Medicare population during the 2009-2010 influenza season. METHODS: We used weekly Medicare claims data to monitor vaccinations and subsequent hospitalizations with principal diagnosis code for GBS within 42 days. Group sequential testing assessed whether the observed GBS rate exceeded a critical limit based on the expected rate from 5 previous years adjusted for claims delay. We evaluated the lag between date of service and date of claims availability and used it for adjustment. RESULTS: By July 30, 2010 (after 26 interim surveillance tests), 14.0 million seasonal and 3.3 million H1N1 vaccinations had accrued. Taking into account claims delay appropriately lowered the critical limit during early monitoring. The observed GBS rate was below the critical limit throughout the surveillance. CONCLUSIONS: Medicare data contributed rapid safety monitoring among millions of 2009-2010 influenza vaccine recipients. Adjustment for claims delay facilitates early detection of potential safety issues. Although limited by lack of medical record review to confirm cases, this claims-based surveillance did not indicate a statistically significant elevated GBS rate following seasonal or H1N1 influenza vaccination.

Outpatient transfusions and occurrence of serious noninfectious transfusion-related complications among US elderly, 2007-2008: utility of large administrative databases in blood safety research.

BACKGROUND: Transfusion-related acute lung injury (TRALI) and hemolytic transfusion reactions account for significant transfusion-related morbidity and mortality in the United States. Our study evaluated types and quantities of transfused components as well as occurrence of TRALI, ABO, and Rh incompatibilities among the US elderly in the institutional outpatient setting during 2007 to 2008. STUDY DESIGN AND METHODS: This retrospective claims-based study utilized the Centers for Medicare & Medicaid Services' large administrative databases. Transfusions were identified by recorded procedure and revenue center codes, while complications were ascertained via ICD-9-CM diagnosis codes. The study quantified blood use based on revenue center units. RESULTS: Among 26,054,242 and 25,662,864 Medicare elderly in 2007 and 2008, a total of 241,055 (0.9%) and 251,284 (1.0%) had outpatient transfusions. Leukoreduced red blood cells (LR-RBCs) was the most frequently transfused single blood component (60.1 and 61.3%, respectively) each year. Likewise, LR-RBCs and LR pheresis platelets (LR-PLTs) was the most frequent component combination (2.4 and 2.6%, respectively). TRALI rate comparison for RBCs and PLTs versus RBCs only showed higher rate for RBCs and PLTs (p = 0.033). In 2007 and 2008, ABO incompatibility rate comparison for irradiated (IR) LR-RBCs versus LR-RBCs showed higher rates for IR LR-RBCs (rate ratio [RR] 37.4, 95% confidence interval [CI] 10.6-132.6; and RR 31.3, 95% CI 11.6-84.4, respectively). CONCLUSION: This study shows potential usefulness of Medicare databases in assessment of blood utilization, transfusion-related complications, and risk factors among US elderly in the outpatient setting. It suggests limitations (e.g., need for several years of data to better assess rare complications) and importance of databases as hypothesis-generating tool to supplement blood safety research.

Babesiosis among elderly Medicare beneficiaries, United States, 2006-2008.

We used administrative databases to assess babesiosis among elderly persons in the United States by year, sex, age, race, state of residence, and diagnosis months during 2006-2008. The highest babesiosis rates were in Connecticut, Rhode Island, New York, and Massachusetts, and findings suggested babesiosis expansion to other states.

Utilizing Medicare claims data for real­time drug safety evaluations:is it feasible?

PURPOSE: The Centers for Medicare & Medicaid Services claims comprise an administrative database of beneficiary-specific clinical information. This study evaluates the impacts of (i) claim information updates (claims adjudication) and (ii) delay in claim processing (claims delay) on real-time evaluation of health service and drug safety signals using the Medicare database. METHODS: Using Medicare claims data accumulated through May 2009 on health services rendered in 2006 and drugs dispensed in 2007, this study measures the frequency with which clinical information changes in the database as a result of (i) claims adjudication and (ii) claims delay. RESULTS: Over 85% of health services claims were processed within 8 weeks after the date of service, and 72% of drug claims were processed within 3 months after the dispense date. Clinical information changed for no more than 3% of unique claim groups in inpatient hospital, outpatient institutional, physician's office, and prescription drug Medicare claim settings. CONCLUSIONS: Claims delay is consistent across time and is minimal. Claims adjudication does not substantially impact the content of clinical information in the Medicare claims database. Therefore, the Medicare claims database provides consistent information regarding health services and prescription drugs in a manner that is prompt enough to facilitate medical product safety evaluations in real time.