Insertable cardiac monitoring results in higher rates of atrial fibrillation diagnosis and oral anticoagulation prescription after ischaemic stroke.

AIMS: After an ischaemic stroke, atrial fibrillation (AF) detection allows for improved secondary prevention strategies. This study aimed to compare AF detection and oral anticoagulant (OAC) initiation in patients with an insertable cardiac monitor (ICM) vs. external cardiac monitor (ECM) after ischaemic stroke. METHODS AND RESULTS: Medicare Fee-for-Service (FFS) insurance claims and Abbott Labs device registration data were used to identify patients hospitalized with an ischaemic stroke in 2017-2019 who received an ICM or ECM within 3 months. Patients with continuous Medicare FFS insurance and prescription drug enrolment in the prior year were included. Patients with prior AF, atrial flutter, cardiac devices, or OAC were excluded. Insertable cardiac monitor and ECM patients were propensity score matched 1:4 on demographics, comorbidities, and stroke hospitalization characteristics. The outcomes of interest were AF detection and OAC initiation evaluated with Kaplan-Meier and Cox proportional hazard regression analyses. A total of 5702 Medicare beneficiaries (ICM, n = 444; ECM, n = 5258) met inclusion criteria. The matched cohort consisted of 2210 Medicare beneficiaries (ICM, n = 442; ECM, n = 1768) with 53% female, mean age 75 years, and mean CHA2DS2-VASc score 4.6 (1.6). Insertable cardiac monitor use was associated with a higher probability of AF detection [(hazard ratio (HR) 2.88, 95% confidence interval (CI) (2.31, 3.59)] and OAC initiation [HR 2.91, CI (2.28, 3.72)] compared to patients monitored only with ECM. CONCLUSION: Patients with an ischaemic stroke monitored with an ICM were almost three times more likely to be diagnosed with AF and to be prescribed OAC compared to patients who received ECM only.

Tricuspid valve disease prevalence and the impact of tricuspid valve surgery on cardiovascular events and hospital resource use in medicare beneficiaries.

BACKGROUND: Tricuspid valve disease (TVD) is presumed common, however, little is known about its prevalence or the impact of tricuspid valve surgery (TVS) on healthcare resource use. METHODS: To describe the prevalence of TVD and assess the impact of TVS on resource utilization, Medicare Fee-For-Service beneficiaries from 2011 -2019 were assessed for the prevalence of non-rheumatic TVD. Hospital costs and rates of all-cause, cardiovascular (CV), and heart failure (HF) hospitalizations were compared in the 3 months pre TVS to acute (0-3 months) and chronic (3 -12 months) post TVS periods. RESULTS: Among 80.3 million beneficiaries from 2011 - 2019 Q1, over 700,000 (0.9%) had non-rheumatic TVD with 1.4% undergoing TVS. Thirty-day and 1 year mortality after TVS was 5.5% to15.5%. Compared with pre-surgery, CV and HF hospitalizations decreased from 0.12 to 0.08 per patient-month (P <.001), and 0.06 to 0.04 (P <.001) acutely. All-cause hospitalizations increased from 0.18 per patient-month to 0.23 per patient-month acutely post-surgery (P <.001), before decreasing to 0.09 per patient-month chronically (P <.001). Hospital costs increased from $2,174 per patient-month to $4,171 per patient-month acutely (P < .001), before falling to $1,441 per patient-month (P < .001) chronically. Lower costs for HF and CV hospitalization in both acute (P = .028 and P < .001, respectively) and chronic (P < .001 for both) periods were observed. CONCLUSIONS: TVS is associated with reduced CV and HF hospitalizations and associated hospital costs. Future work should determine whether transcatheter tricuspid valve repair offers similar or additional benefits.

Initiating GLP-1 Therapy in Combination with FreeStyle Libre Provides Greater Benefit Compared with GLP-1 Therapy Alone.

Background and Aim: Glucagon-like peptide-1 receptor agonists (GLP-1 RA) therapy provides glycemic benefits to individuals with type 2 diabetes (T2D). However, the effects of GLP-1 RA therapy in combination with FreeStyle Libre systems (FSL) are unknown. This study aimed to compare changes in hemoglobin A1c (HbA1c) between people acquiring GLP-1 with FSL (GLP-1+FSL) versus GLP-1 without FSL (GLP-1). Methods: This real-world study used Optum's de-identified Market Clarity Data, a linked electronic health records (EHR)-claims database, and included adults with T2D and HbA1c ≥8% who acquired their first GLP-1 RA medication between 2018 and 2022. GLP-1+FSL subjects acquired their first FSL within ±30 days of their first GLP-1 acquisition. Cohorts were matched 1:5 on baseline insulin therapy, age, sex, baseline HbA1c, and GLP-1 type. Paired changes in HbA1c were compared between unmatched and matched groups at 6 months. Results: The study included 24,724 adults in the unmatched cohort (GLP-1+FSL, n = 478; GLP-1, n = 24,246). The matched cohort included 478 GLP-1+FSL users and 2,390 GLP-1 users: mean age 53.5 ± 11.8 and 53.5 ± 11.3 years, HbA1c 10.25 ± 1.68% and 10.22 ± 1.69%, respectively. HbA1c reduction was greater in the GLP-1+FSL group compared with the GLP-1 group in the unmatched cohort (-2.43% vs. -1.73%, difference 0.70%, P < 0.001, respectively) and in the matched cohort (-2.43% vs. -2.06%, difference 0.37%, P < 0.001). GLP-1+FSL vs. GLP-1 treatment was associated with greater HbA1c reduction in the intensive insulin (-2.32% vs. -1.50%), nonintensive insulin (-2.50% vs. -1.74%), and noninsulin group (-2.46% vs. -1.78%), as well as in patients using semaglutide (-2.73% vs. -1.92%) and dulaglutide (-2.45% vs. -1.71%) GLP-1 RA, all P < 0.001. Conclusions: Adults with suboptimally controlled T2D, initiating GLP-1 RA with FreeStyle Libre, had greater improvement in HbA1c compared with those treated with GLP-1 RA only. These results suggest an additional glycemic benefit of FSL when used with a GLP-1 RA in T2D treatment.

Association of Changes in A1C Following Continuous Glucose Monitoring Acquisition in People with Sub-Optimally Treated Type 2 Diabetes Taking GLP-1 RA Therapy.

INTRODUCTION: Both glucagon-like peptide-1 receptor agonists (GLP-1 RA) and continuous glucose monitoring (CGM) improve glycemia in patients with type 2 diabetes (T2D). However, it is unknown whether adding CGM to GLP-1 RA therapy further improves A1c. We evaluated changes in A1c levels 6 months after initiation of FreeStyle Libre (FSL) in adults with sub-optimally controlled T2D already on GLP-1 RA therapy. METHODS: This retrospective, observational study used Optum's de-identified Market Clarity Data, a linked electronic health record-claims database to assess changes in A1c after FSL acquisition. Inclusion criteria were T2D diagnosis, ≥ 18 years, baseline A1c ≥ 8%, with the first FSL acquisition between 2018 and 2022. Patients were required to be on GLP-1 RA prior to FSL with at least one GLP-1 RA prescription within 90 days of FSL acquisition. GLP-1 RA initiation was defined as the earliest GLP-1 RA prescription from 2017 onwards. Paired changes in A1c were assessed at 6 months after initial FSL acquisition. RESULTS: The study cohort included 1454 adults with T2D (age 55 ± 10 years, 52% male, 38% with intensive insulin therapy, median 471 days from GLP-1 RA initiation to FSL, and baseline A1c 9.8 ± 1.5%). After FSL acquisition, patients experienced an A1c decrease of 1.5 ± 1.9% (p < 0.001). Patients with a baseline A1c > 10% had the largest reduction (n = 497, - 2.7 ± 2.2%, p < 0.001). Significant improvements were observed in subgroups based on insulin therapy and GLP-1 RA formulation. Those initiating GLP-1 RA therapy > 24 months before FSL acquisition also showed improvements in A1c (n = 478; - 1.3 ± 1.7%, p < 0.001). CONCLUSIONS: In a large, real-world study of adults with T2D, those on prior GLP-1 RA therapy experienced significant A1c improvements after acquiring FSL, irrespective of GLP-1 RA duration, GLP-1 RA formulation, or insulin therapy type. These findings support the use of FSL in adults with T2D treated with GLP-1 RA.

Comparing clinical outcomes between two continuous glucose monitors: similar diabetes-related events, all-cause hospitalizations and HbA1c reductions in type 1 and type 2 diabetes.

Objectives: We compared clinical outcomes after acquiring a FreeStyle Libre© Flash Continuous Glucose Monitoring System (FSL) or Dexcom (DEX) continuous glucose monitoring (CGM) device in individuals with type 1 diabetes (T1D) and type 2 diabetes (T2D) treated with intensive insulin therapy. Design and Methods: This retrospective analysis of the IBM® MarketScan® Research Databases and IBM® Explorys® Electronic Health Records Database assessed differences in acute diabetes-related events (ADE), all-cause hospitalizations (ACH) and glycated hemoglobin (HbA1c) in T1D and T2D populations 6 months post CGM acquisition. Analyses were conducted in two study cohorts (Cohort 1, n = 7,494; Cohort 2, n = 678). Participants were T1D or T2D, age ≥ 18 years, treated with short or rapid-acting insulin and naïve to CGM, who acquired a CGM system. Users were propensity score matched on demographics and clinical factors. Results: Cohort 1: Post-CGM ADE-free rates at 6 months ranged from 94.8 to 96.7% and ACH-free rates ranged from 90.4 to 95.4%, for both T1D and T2D groups, with no significant differences between CGM systems. Cohort 2: Significant HbA1c reductions were associated with use of the DEX and FSL devices in the T1D (-0.35% and -0.37%, respectively) and T2D (-0.73% and -0.79%, respectively) cohorts, both p < 0.001, with no significant differences in the magnitude of reduction between systems (T1D p = 0.99 and T2D p = 0.84). Conclusions: Acquisition of the FSL and DEX systems was associated with similar rates of acute diabetes-related events and all-cause hospitalizations and similar HbA1c reductions in adults with T1D and T2D.

Ambulatory Pulmonary Artery Pressures After Transcatheter Edge-to-Edge Repair of the Mitral Valve in Patients With Heart Failure and Mitral Regurgitation.

The objective of this study was to assess ambulatory hemodynamics after transcatheter edge-to-edge repair (TEER) of the mitral valve. Pulmonary artery pressure (PAP) measurements from implanted sensors were collected through a remote monitoring database and linked to Medicare fee-for-service claims data. Among patients with linked data, those undergoing TEER were included if the ambulatory PAP monitor was implanted ≥3 months before TEER and ≥3 months of PAP data after TEER were available. The primary end point was diastolic PAP (dPAP) at 3 months after TEER compared with baseline. A total of 50 patients undergoing TEER between July 2014 and March 2020 were included, with an average age of 75 ± 8 years and 70% were men. dPAP was significantly lower at 3 months after TEER than baseline, -1.8 ± 4.8 mm Hg, p = 0.010. The cumulative reduction in dPAP (area under the curve) was significantly lower at 3 months after TEER, 113 ± 267 mm Hg-days, p = 0.004. A reduction in dPAP at 3 months after TEER was independently associated with a significantly lower risk of heart failure hospitalization (p = 0.023). TEER of the mitral valve is associated with a clinically relevant and sustained reduction in dPAP.

The effect of school dropout on verbal ability in adulthood: a propensity score matching approach.

Compared to high school graduates, adolescents who drop out of school are more likely to have a range of negative outcomes, including lower verbal capacities; however, the true nature of this association is not well-understood. Dropping out of school could have an important effect on reducing verbal skills, or the link between dropping out of school and diminished verbal skills could be a spurious association that is the result of unmeasured confounding variables. The current study tested these two competing perspectives by using propensity-score-matching (PSM) to unpack the association between school dropout and verbal skills among 7,317 respondents from the National Longitudinal Study of Adolescent Health (51% female, 49% male; 62% Caucasian, 38% minority). The results of the PSM models indicated a small yet meaningful statistically significant effect of dropout on verbal skills in adulthood even after taking into account a range of confounders. We conclude by discussing the implications of our results.

Flash CGM associated with event reduction in nonintensive diabetes therapy.

OBJECTIVES: We evaluated the effects of acquiring a flash continuous glucose monitoring (CGM) system in the population with type 2 diabetes (T2D) treated with basal or noninsulin therapy. STUDY DESIGN: This was a retrospective database analysis of the IBM MarketScan Commercial Claims and Medicare Supplemental databases that assessed rates of acute diabetes-related events (ADEs) and all-cause inpatient hospitalizations (ACHs) in a large population with T2D treated with basal insulin therapy or noninsulin medications. ADE and ACH rates 6 months prior to and 6 months post CGM acquisition were compared. METHODS: Inclusion criteria for analysis were diagnosis of T2D; age 18 years or older; treatment with long-acting, neutral protamine Hagedorn, or premixed insulin or noninsulin therapy; naïve to CGM; and acquisition of their flash CGM system between October 2017 and March 2019. Patients served as their own controls. Event rates were compared using weighted Cox regression with Andersen-Gill extension for repeat events. RESULTS: A cohort of 10,282 adults with T2D (mean [SD] age, 53.1 [9.6] years; 51.9% male) who met inclusion criteria were assessed. ADE rates decreased from 0.076 to 0.052 events per patient-year (HR, 0.68; 95% CI, 0.58-0.80; P < .001). ACH rates decreased from 0.177 to 0.151 events per patient-year (HR, 0.85; 95% CI, 0.77-0.94; P = .002). CONCLUSIONS: Acquisition of the flash CGM system was associated with significant reductions in outpatient and inpatient ADEs and ACHs. These findings provide compelling evidence that use of flash CGM in patients with T2D treated with basal insulin therapy or noninsulin therapy improves clinical outcomes and potentially reduces costs.

Flash CGM Is Associated With Reduced Diabetes Events and Hospitalizations in Insulin-Treated Type 2 Diabetes.

PURPOSE: Suboptimal glycemic control among individuals with diabetes is a leading cause of hospitalizations and emergency department utilization. Use of flash continuous glucose monitoring (flash CGM) improves glycemic control in type 1 and type 2 diabetes, which may result in lower risk for acute and chronic complications that require emergency services and/or hospitalizations. METHODS: In this retrospective, real-world study, we analyzed IBM MarketScan Commercial Claims and Medicare Supplemental databases to assess the impact of flash CGM on diabetes-related events and hospitalizations in a cohort of 2463 individuals with type 2 diabetes who were on short- or rapid-acting insulin therapy. Outcomes were changes in acute diabetes-related events (ADE) and all-cause inpatient hospitalizations (ACH), occurring during the first 6 months after acquiring the flash CGM system compared with event rates during the 6 months prior to system acquisition. ICD-10 codes were used to identify ADE for hypoglycemia, hypoglycemic coma, hyperglycemia, diabetic ketoacidosis, and hyperosmolarity. RESULTS: ADE rates decreased from 0.180 to 0.072 events/patient-year (hazard ratio [HR]: 0.39 [0.30, 0.51]; P < 0.001) and ACH rates decreased from 0.420 to 0.283 events/patient-year (HR: 0.68 [0.59 0.78]; P < 0.001). ADE reduction occurred regardless of age or gender. CONCLUSIONS: Acquisition of the flash CGM system was associated with reductions in ADE and ACH. These findings provide support for the use of flash CGM in type 2 diabetes patients treated with short- or rapid-acting insulin therapy to improve clinical outcomes and potentially reduce costs.

Clinical outcomes and healthcare expenditures in the real world with left ventricular assist devices - The CLEAR-LVAD study.

BACKGROUND: Several distinctly engineered left ventricular assist devices (LVADs) are in clinical use. However, contemporaneous real world comparisons have not been conducted, and clinical trials were not powered to evaluate differential survival outcomes across devices. OBJECTIVES: Determine real world survival outcomes and healthcare expenditures for commercially available durable LVADs. METHODS: Using a retrospective observational cohort design, Medicare claims files were linked to manufacturer device registration data to identify de-novo, durable LVAD implants performed between January 2014 and December 2018, with follow-up through December 2019. Survival outcomes were compared using a Cox proportional hazards model stratified by LVAD type and validated using propensity score matching. Healthcare resource utilization was analyzed across device types by using nonparametric bootstrap analysis methodology. Primary outcome was survival at 1-year and total Part A Medicare payments. RESULTS: A total of 4,195 de-novo LVAD implants were identified in fee-for-service Medicare beneficiaries (821 HeartMate 3; 1,840 HeartMate II; and 1,534 Other-VADs). The adjusted hazard ratio for mortality at 1-year (confirmed in a propensity score matched analysis) for the HeartMate 3 vs HeartMate II was 0.64 (95% CI; 0.52-0.79, p< 0.001) and for the HeartMate 3 vs Other-VADs was 0.51 (95% CI; 0.42-0.63, p < 0.001). The HeartMate 3 cohort experienced fewer hospitalizations per patient-year vs Other-VADs (respectively, 2.8 vs 3.2 EPPY hospitalizations, p < 0.01) and 6.1 fewer hospital days on average (respectively, 25.2 vs 31.3 days, p < 0.01). The difference in Medicare expenditures, conditional on survival, for HeartMate 3 vs HeartMate II was -$10,722, p < 0.001 (17.4% reduction) and for HeartMate 3 vs Other-VADs was -$17,947, p < 0.001 (26.1% reduction). CONCLUSIONS: In this analysis of a large, real world, United States. administrative dataset of durable LVADs, we observed that the HeartMate 3 had superior survival, reduced healthcare resource use, and lower healthcare expenditure compared to other contemporary commercially available LVADs.

Cross-sectional imaging of the torso reveals occult injuries in asymptomatic blunt trauma patients.

Background: High morbidity and mortality rates of trauma injuries make early detection and correct diagnosis crucial for increasing patient's survival and quality of life after an injury. Improvements in technology have facilitated the rapid detection of injuries, especially with the use of computed tomography (CT). However, the increased use of CT imaging is not universally advocated for. Some advocate for the use of selective CT imaging, especially in cases where the severity of the injury is low. The purpose of this study is to review the CT indications, findings, and complications in patients with low Injury Severity Scores (ISS) to determine the utility of torso CT in this patient cohort. Methods: A retrospective review of non-intubated, adult blunt trauma patients with an initial GCS of 14 or 15 evaluated in an ACS verified level 1 trauma center from July 2012 to June 2015 was performed. Data was obtained from the hospital's trauma registry and chart review, with the following data included: age, sex, injury type, ISS, physical exam findings, all injuries recorded, injuries detected by torso CT, missed injuries, and complications. The statistical tests conducted in the analysis of the collected data were chi-squared, Fischer exact test, and ANOVA analysis. Results: There were 2306 patients included in this study, with a mean ISS of 8. For patients with a normal chest exam that had a chest CT, 15% were found to have an occult chest injury. In patients with a negative chest exam and negative chest X-ray, 35% had occult injuries detected on chest CT. For patients with a negative abdominal exam and CT abdomen and pelvis, 16% were found to have an occult injury on CT. Lastly, 25% of patients with normal chest, abdomen, and pelvis exams with chest, abdomen, and pelvis CT scans demonstrated occult injuries. Asymptomatic patients with a negative CT had a length of stay 1 day less than patients without a corresponding CT. No incidents of contrast-induced complications were recorded. Conclusions: A negative physical exam combined with a normal chest X-ray does not rule out the presence of occult injuries and the need for torso imaging. In blunt trauma patients with normal sensorium, physical exam and chest X-ray, the practice of obtaining cross-sectional imaging appears beneficial by increasing the accuracy of total injury burden and decreasing the length of stay.

Increased healthcare utilization associated with complete atrioventricular block in pacemaker patients.

PURPOSE: The purpose of the current study is to characterize and quantify the impact of complete atrioventricular block (cAVB) on heart failure hospitalization (HFH) and healthcare utilization in pacemaker (PM) patients. METHODS: Patients ≥ 18 years implanted with a dual-chamber PM from April 2008 to March 2014 were selected from the MarketScan® Commercial and Medicare Supplemental claims databases. Patients with ≤ 1-year continuous MarketScan enrollment prior to and post-implant, and those with prior HF diagnosis were excluded. Patients were dichotomized into those with cAVB, defined as a 3rd degree AVB diagnosis or AV node ablation in the year prior to PM implant, versus those without any AVB (noAVB). Post-implant HFH and associated costs were compared based on inpatient claims. RESULTS: The study cohort included 21,202 patients, of which 14,208 had no AVB and 6994 had cAVB, followed for 2.39 and 2.27 years, respectively. Patients with cAVB were associated with a significantly increased risk of cumulative HFH (HR 1.59 [95% CI 1.35-1.86] p < 0.001) and significantly higher costs ($636 [609-697] vs $369 [353-405] per pt-year, p < 0.001) compared to those with no AVB. CONCLUSIONS: Among dual-chamber PM patients without prior HF, cAVB is associated with a significantly increased risk of HFH and greater HF-related healthcare utilization. Identifying patients at high risk for HF in the setting of RV pacing, and potentially earlier use of biventricular or selective conduction system pacing, may reduce HF-related healthcare utilization.

Incidence and Time Course for Developing Heart Failure With High-Burden Right Ventricular Pacing.

BACKGROUND: Although right ventricular pacing can contribute to cardiomyopathy, the impact of complete atrioventricular block (cAVB) on heart failure (HF) development in pacemaker patients has not been well characterized. We evaluated the incidence and time course for developing HF after pacemaker implantation for cAVB. METHODS AND RESULTS: A MarketScan database identified patients undergoing dual-chamber pacemaker implantation from 2008 to 2014. Patients with cAVB were identified by an atrioventricular node ablation or diagnosis of third-degree AVB. Patients with ≥1 year of continuous MarketScan enrollment before and after implant and without a previous diagnosis of HF were dichotomized into those with cAVB and without AVB. The primary end point was new HF assessed over acute (0-6 months) and chronic (6 months to 4 years) phases post-pacemaker implantation. The cohort included 6994 cAVB patients and 14 208 patients without AVB, followed for 2.35 years (interquartile range, 1.62-3.39 years). After adjustment for baseline covariates, patients with cAVB experienced an increased risk of new-onset HF in the acute phase (hazard ratio, 1.62; 95% confidence interval, 1.48-1.79; P<0.001). Although the risk of HF remained elevated among those with cAVB in the chronic phase, the effect was attenuated (hazard ratio, 1.16; 95% confidence interval, 1.08-1.25; P<0.001). After pacemaker implantation, younger patients (≤55 years of age) and those with an antecedent history of atrial fibrillation experienced the highest risk of HF associated with cAVB. CONCLUSIONS: Patients with a diagnosis of cAVB, and thus presumed to have a higher burden of right ventricular pacing, experienced an increased risk of new-onset HF after pacemaker implantation compared with those without AVB. Better tools are needed to identify patients at high risk of developing HF in the setting of right ventricular pacing and to determine whether these patients benefit from upfront biventricular pacing.

Clinical Outcomes After Ablation of the AV Junction in Patients With Atrial Fibrillation: Impact of Cardiac Resynchronization Therapy.

BACKGROUND: Patients with atrial fibrillation (AF) often undergo AV junction ablation (AVJA) and pacemaker implantation. Right ventricular (RV) pacing contributes to increased risk of heart failure (HF), which may be mitigated by biventricular pacing. We sought to determine the impact of AVJA concurrent with RV versus biventricular pacemaker implantation on AF and HF hospitalizations. METHODS AND RESULTS: The MarketScan Commercial and Medicare Supplemental claims database was used to select 18- to 100-year-old patients with AF with pacemaker implantation. Patients were divided into those with an RV and a biventricular pacemaker and further into those who did (AVJA+) or did not undergo concurrent ablation. Separately, the AVJA+ group was divided into those receiving RV versus biventricular pacemakers. AF and HF hospitalization rates were compared between groups after matching on demographics, comorbidities, and baseline hospitalization rates. The study included 24 361 patients, with RV (n=23 377) or biventricular (n=984) pacemakers; 1611 patients underwent AVJA. AVJA+ was associated with reduced AF hospitalization risk (RV hazard ratio [HR], 0.31; P<0.001; biventricular HR, 0.20; P=0.003) compared with no AVJA. However, HF hospitalization risk was increased for RV (HR, 1.63; P=0.001), but not biventricular (HR, 0.98; P=0.942), pacemakers. In AVJA+ patients, biventricular pacing was associated with reduced risk of HF hospitalization versus RV pacing (HR, 0.62; P=0.017). CONCLUSIONS: In a large cohort of patients with AF, AVJA+ significantly reduced AF hospitalizations, irrespective of whether an RV or a biventricular pacemaker was implanted. However, AVJA was associated with a marked HF hospitalization increase in patients with an RV pacemaker, which was ameliorated with biventricular pacing.

Eicosapentanoic acid inhibits hypoxia-reoxygenation-induced injury by attenuating upregulation of MMP-1 in adult rat myocytes.

BACKGROUND: Myocardial hypoxia-reoxygenation (H-R) is associated with upregulation of metalloproteinases (MMPs). Upregulation of MMPs is associated with cell injury. Previous studies have shown that fish oil can protect myocardium from injury induced by H-R. This study was designed to examine the effect of eicosapentanoic acid (EPA), one of the major components in fish oil, on the modulation of MMP-1 expression in response to H-R in cultured adult rat myocytes. METHODS AND RESULTS: Myocytes isolated from adult Sprague-Dawley rat hearts were cultured with or without EPA or arachidonic acid (AA) (10 and 50 microM) and exposed to 24 h of hypoxia followed by 3 h of reoxygenation (H-R). H-R resulted in myocyte injury (measured on LDH release), increase in p38MAPK phosphorylation (Western analysis), augmentation of lipid peroxidation, and upregulation of MMP-1 activity (zymography) and expression (RT-PCR and Western analysis) (all P<0.01 vs. control, n=5). Pretreatment of myocytes with EPA, but not AA, resulted in a reduction in LDH release, and attenuation of p38MAPK phosphorylation and MMP-1 activity and expression in response to H-R (all P<0.05 vs. H-R alone). Pretreatment of myocytes with EPA also reduced lipid peroxidation in myocytes exposed to H-R (P<0.05 vs. H-R alone). A high concentration of EPA (50 microM) was more potent than the lower concentration of EPA (10 microM). CONCLUSIONS: These observations suggest that EPA attenuates an increase in MMP-1 following H-R, which may be a basis of protection of myocytes from the adverse effects of H-R. p38MAPK phosphorylation may be an important signaling event in this process.

EPA and DHA attenuate ox-LDL-induced expression of adhesion molecules in human coronary artery endothelial cells via protein kinase B pathway.

Uptake of oxidized low-density lipoprotein (ox-LDL) by endothelial cells is a critical step for the initiation and development of atherosclerosis. Adhesion molecules are inflammatory makers, which are upregulated by ox-LDL and play a pivotal role in atherogenesis. A number of studies suggest that fish and its constituents can reduce inflammation and decrease atherosclerosis. We hypothesized that fish oil constituents namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) may reduce expression of adhesion molecules induced by ox-LDL. Cultured human coronary artery endothelial cells (HCAECs) were incubated with ox-LDL for 24 h. Parallel groups of cells were pretreated with DHA or EPA (10 or 50 microM) overnight before incubation with ox-LDL. Ox-LDL markedly increased the expression of P-selectin and intracellular adhesion molecule-1 (ICAM-1) (both protein and mRNA) in HCAECs, and enhanced the adhesion of monocytes to the cultured HCAECs. Both EPA and DHA decreased ox-LDL-induced upregulation of expression of P-selectin and ICAM-1, and the enhanced adhesion of monocytes to HCAECs. To determine the role of protein kinase B (PKB) as an intracellular-signaling pathway, HCAECs were treated with the PKB upstream inhibitor wortmannin (100 nM) or transfected with plasmids encoding dominant-negative mutants of PKB (PKB-DN) before treatment with DHA. Ox-LDL alone downregulated the activity of PKB; DHA attenuated this effect of ox-LDL, and both wortmannin and PKB-DN blocked the effect of DHA. The present study in human coronary endothelial cells suggests that both EPA and DHA attenuate ox-LDL-induced expression of adhesion molecules, and the adhesion of monocytes to HCAECs by modulation of PKB activation. These effects may be important mechanisms of anti-atherosclerotic effects of fish and fish oils.