Sex differences in the effectiveness and tolerability of dolutegravir plus rilpivirine as a switch strategy in people living with HIV.

INTRODUCTION: Dolutegravir + rilpivirine (DTG + RPV) is an effective antiretroviral therapy regimen approved in clinical guidelines as a switch therapy for virologically suppressed people with HIV. Our study aimed to compare the effectiveness and tolerability of DTG + RPV in women and men in real-world clinical practice. METHODS: This was a retrospective analysis of treatment-experienced people with HIV from a large HIV unit who switched to DTG + RPV. We analysed treatment effectiveness, rates of adverse events and discontinuation, and metabolic changes after 48 weeks of treatment. HIV-RNA levels <50 copies/mL were analysed at 48 weeks using both intention-to treat analysis (where missing data were interpreted as failures) and per-protocol analysis (excluding those with missing data or changes due to reasons other than virological failure). Outcomes were compared between women and men based on sex at birth. RESULTS: A total of 307 patients were selected (71 women and 236 men). No transgender people were included. At baseline, women had lived with HIV infection and received antiretroviral therapy for longer than men (23.2 vs 17.4 years and 18.9 vs 14.2 years, respectively). In the intention-to-treat analysis, 74.6% (95% confidence interval [CI] 63.4-83.3%) of women and 83.5% (95% CI 78.2-87.7) of men had HIV-RNA <50 copies/mL. In the per-protocol analysis, 96.4% (95% CI 87.7-99) of women and 99% (95% CI 98.9-99.7) of men had HIV-RNA levels <50 copies/mL. Two women and two men had HIV-RNA >50 copies/mL at 48 weeks. Discontinuation due to adverse events was more frequent in women than in men: 12.7% vs 7.2% (p < 0.02). Neuropsychiatric and gastrointestinal events were the most frequently reported. A median (interquartile range) weight gain of 1.9 kg (0-4.2) in women and 1.2 kg (-1-3.1) in men was reported (median of differences between baseline visit and week 48); the remaining changes in metabolic parameters were neutral. CONCLUSIONS: DTG + RPV exhibited good and similar virological effectiveness in women and men in real-world settings. However, poorer tolerability and more treatment interruptions were observed in women.

Epidemiological characteristic and prognosis changes in chronic hepatitis B in people living with HIV.

INTRODUCTION: Due to hepatitis B virus (HBV) treatment and vaccination during the last decades in Spain, epidemiological and prognosis of chronic hepatitis B (CHB) may have changed. METHODS: Retrospective review of CHB-HIV coinfected patients in a single reference center in Madrid until year 2019. We compared incidence, epidemiological and clinical characteristics according diagnosis period (before 2000, 2000-2004, 2005-2009, 2010-2014, 2015-2019). A retrospective longitudinal study was done to assess mortality, related risk factors and hepatic decompensation. RESULTS: Out of 5452 PLHIV, 160 had CHB (prevalence 2.92%; 95%CI 2.5-3.4), 85.6% were men, median age 32.1 (27-37.2). Incidence rate did not change over the years (2.4/100 patients-year). PLHIV with CHB diagnosed before year 2000 (n = 87) compared with those diagnosed between 2015 and 2019 (n = 11) were more often native-Spanish (90.8% vs. 18.2%), had infected using intravenous drugs (55.2% vs. 0), were coinfected with hepatitis C (40% vs. 9.1%) or hepatitis delta virus (30.4% vs. 0) and had more severe liver disease (cirrhosis 24.1% vs. 0). After a median follow-up of 20.4 years, 23 patients died (7.1/1000 patients-year) and 19 had liver decompensation (4.9/1000 patients-year). All deaths and liver decompensation occurred in patients diagnosed before year 2010. Mortality was associated with higher liver fibrosis in Fibroscan® (HR 1.06, 95% CI 1.03-1.09). CONCLUSION: The epidemiology of CHB in PLHIV in our cohort is changing with less native Spanish, more sexually transmitted cases and less coinfection with other hepatotropic virus. Patients diagnosed before 2010 have worst prognosis related to higher grades of liver fibrosis.

CD6 and Its Interacting Partners: Newcomers to the Block of Cancer Immunotherapies.

Cancer management still requires more potent and safer treatments, of which immunomodulatory receptors on the lymphocyte surface have started to show promise in new cancer immunotherapies (e.g., CTLA-4 and PD-1). CD6 is a signal-transducing transmembrane receptor, mainly expressed by all T cells and some B and NK cell subsets, whose endogenous ligands (CD166/ALCAM, CD318/CDCP-1, Galectins 1 and 3) are overexpressed by malignant cells of different lineages. This places CD6 as a potential target for novel therapies against haematological and non-haematological malignancies. Recent experimental evidence for the role of CD6 in cancer immunotherapies is summarised in this review, dealing with diverse and innovative strategies from the classical use of monoclonal antibodies to soluble recombinant decoys or the adoptive transfer of immune cells engineered with chimeric antigen receptors.

The T6SS-Dependent Effector Re78 of Rhizobium etli Mim1 Benefits Bacterial Competition.

The genes of the type VI secretion system (T6SS) from Rhizobium etli Mim1 (ReMim1) that contain possible effectors can be divided into three modules. The mutants in them indicated that they are not required for effective nodulation with beans. To analyze T6SS expression, a putative promoter region between the tssA and tssH genes was fused in both orientations to a reporter gene. Both fusions are expressed more in free living than in symbiosis. When the module-specific genes were studied using RT-qPCR, a low expression was observed in free living and in symbiosis, which was clearly lower than the structural genes. The secretion of Re78 protein from the T6SS gene cluster was dependent on the presence of an active T6SS. Furthermore, the expression of Re78 and Re79 proteins in E. coli without the ReMim1 nanosyringe revealed that these proteins behave as a toxic effector/immunity protein pair (E/I). The harmful action of Re78, whose mechanism is still unknown, would take place in the periplasmic space of the target cell. The deletion of this ReMim1 E/I pair resulted in reduced competitiveness for bean nodule occupancy and in lower survival in the presence of the wild-type strain.

Impact of preexisting nucleos(t)ide reverse transcriptase inhibitor resistance on the effectiveness of bictegravir/emtricitabine/tenofovir alafenamide in treatment experience patients.

INTRODUCTION: Few clinical trials and cohort studies have evaluated the efficacy of bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) in people with HIV (PWH) with preexisting M184V/I or other nucleos(t)ide reverse transcriptase inhibitor (NRTI) resistance-associated mutations (RAMs). Real-world data are also scarce. METHODS: Retrospective review of treatment-experienced patients who started B/F/TAF in a cohort of PWH. HIV-RNA less than 50 copies/ml was analyzed at 48 weeks in an intention-to-treat (ITT) analysis (missing=failure) and per protocol analysis (patients with missing data or changes for reasons other than virological failure were excluded). Results were compared in patients with and without previous NRTI-RAMs. RESULTS: Five hundred and six PWH were included (16.2% women). Median age and time with HIV infection were 52.3 and 18.9 years, respectively. At baseline, viral load was less than 50 copies/ml in 440 patients (86.6%). Overall, 69 (13.6%) participants had documented preexisting NRTI-RAMs: 57 (11.2%) M184V/I and 30 (5.9%) tenofovir RAMs. In the ITT analysis, 83% (420/506) had HIV-RNA less than 50 copies/ml [82.2% (359/437) and 88.4% (61/69) in persons without and with NRTI-RAMs, respectively ( P  = 0.2)]. In the per protocol analysis 94.2% (420/445) had HIV-RNA less than 50 copies/ml [94.4% (359/380) vs. 93.8% (61/65); P  = 0.2]. A total of 61 participants were excluded from the per protocol analysis (23 missing data, 19 discontinued B/F/TAF because of toxicity, 13 for other reasons, and 6 died). CONCLUSION: Switching to B/F/TAF is well tolerated and effective in the real-world setting, even in patients with preexisting NRTI RAMs, such as M184V and RAMs conferring resistance to tenofovir. These results confirm the robustness of this combination.

Acute hepatitis B among HIV positive persons: A two-decade review of cases from a Spanish cohort.

PURPOSE: To review the incidence and characteristics of acute hepatitis B (AHB) in a large cohort of HIV infected persons from a low prevalence region during the last two decades. METHODS: Retrospective review of an HIV Cohort from a single reference centre in Madrid, Spain, between 2000 and 2018. AHB was diagnosed in persons with newly acquired HBAgS and acute hepatitis with positive IgM anti-HBc. RESULTS: Out of 5443 HIV+ patients in our cohort (3098 anti-HBc negative), 18 developed AHB from 2000 to 2018. The global incidence was 0.02 (0.01-0.04) per 100 patient-year in the entire population and 0.06 (0.01-0.1) per 100 patient-year in the anti-HBc negative population. A statistically significant decrease in AHB incidence was observed during these years (ß=-0.006; p=0.047). All 18 patients diagnosed with AHB were men, the majority (16) occurred in men who have sex with men. AHB was observed in 4 persons previously unresponsive to vaccination. Regarding antiretroviral treatment (ART), 15 were not receiving ART, two persons were on ART with any HBV active drugs and one person had lamivudine in the regimen. Two persons (11%) developed chronic hepatitis B. There were no cases of fulminant hepatitis. CONCLUSION: The incidence of AHB in HIV positive persons in our cohort was low and shows a progressive decline in the last 20 years. Cases occurred in persons not protected against VHB: not vaccinated or non-responders to vaccine that were not receiving tenofovir.

Pre-Treatment with Grape Seed Extract Reduces Inflammatory Response and Oxidative Stress Induced by Helicobacter pylori Infection in Human Gastric Epithelial Cells.

Helicobacter pylori (H. pylori) is a pathogenic bacteria identified as a potential risk factor for gastritis, gastric ulcers and gastric cancer. During the stomach colonization, H. pylori triggers a strong inflammatory response and subsequent oxidative stress, which are associated with tissue damage. For this reason, it is of particular interest to develop alternative natural tools that enable modulation of the associated damaging immune response. With this purpose, we obtained grape seed extract (GSE) from sweet (not fermented) food grade seeds. The aim of our study was to investigate the effect of GSE and its two enriched procyanidins fractions (OPC and PPC) on the inflammatory process and oxidative stress produced by different H. pylori strains in human gastric epithelial cells (AGS). Anti-inflammatory activity was evaluated by measuring the level of interleukin-8 (IL-8) secretion. IL-8 production was significantly reduced in H. pylori-infected human gastric epithelial cells pre-treated with GSE or its enriched fractions when compared with non-pre-treated infected cells (from 21.6% to 87.8%). Pre-treatment with GSE or its fractions significantly decreased intracellular reactive oxygen species (ROS) production in AGS cells after infection, depending on the H. pylori strain. Our results also showed that GSE and its fractions demonstrate antibacterial activity against all strains of H. pylori used in the study. This work demonstrates the effectiveness of GSE enriched in procyanidins against the main events associated with H. pylori infection.

Acute hepatitis B among HIV positive persons: A two-decade review of cases from a Spanish cohort.

PURPOSE: To review the incidence and characteristics of acute hepatitis B (AHB) in a large cohort of HIV infected persons from a low prevalence region during the last two decades. METHODS: Retrospective review of an HIV Cohort from a single reference centre in Madrid, Spain, between 2000 and 2018. AHB was diagnosed in persons with newly acquired HBAgS and acute hepatitis with positive IgM anti-HBc. RESULTS: Out of 5443 HIV+ patients in our cohort (3098 anti-HBc negative), 18 developed AHB from 2000 to 2018. The global incidence was 0.02 (0.01-0.04) per 100 patient-year in the entire population and 0.06 (0.01-0.1) per 100 patient-year in the anti-HBc negative population. A statistically significant decrease in AHB incidence was observed during these years (ß=-0.006; p=0.047). All 18 patients diagnosed with AHB were men, the majority (16) occurred in men who have sex with men. AHB was observed in 4 persons previously unresponsive to vaccination. Regarding antiretroviral treatment (ART), 15 were not receiving ART, two persons were on ART with any HBV active drugs and one person had lamivudine in the regimen. Two persons (11%) developed chronic hepatitis B. There were no cases of fulminant hepatitis. CONCLUSION: The incidence of AHB in HIV positive persons in our cohort was low and shows a progressive decline in the last 20 years. Cases occurred in persons not protected against VHB: not vaccinated or non-responders to vaccine that were not receiving tenofovir.

The Type VI secretion system of Rhizobium etli Mim1 has a positive effect in symbiosis.

The Type VI secretion systems (T6SSs) allow bacteria to translocate effector proteins to other bacteria or to eukaryotic cells. However, little is known about the role of T6SS in endosymbiotic bacteria. In this work we describe the T6SS of Rhizobium etli Mim1, a bacteria able to effectively nodulate common beans. Structural genes and those encoding possible effectors have been identified in a 28-gene DNA region of R. etli Mim1 pRetMIM1f plasmid. Immunodetection of Hcp protein, a conserved key structural component of T6SS systems, indicates that this secretion system is active at high cell densities, in the presence of root exudates, and in bean nodules. Rhizobium etli mutants affected in T6SS structural genes produced plants with lower dry weight and smaller nodules than the wild-type strain, indicating for the first time that the T6SS plays a positive role in Rhizobium-legume symbiosis.

Switching from tenofovir containing regimens to boosted protease inhibitor monotherapy: Impact on renal function.

OBJECTIVE: To evaluate the effect on creatinine clearance (CG-CrCl, Cockcroft-Gault equation) of switching to boosted protease inhibitor (PI) monotherapy in patients receiving a triple drug antiretroviral regimen containing TDF. METHODS: All patients who had received a TDF-containing regimen for at least one year and had been switched to PI monotherapy were included. A rapid decrease in CG-CrCl during exposure to TDF was defined as a decrease in CG-CrCl at least five times higher than the expected due to age (0.4ml/min/year by the years of exposure to TDF). In this subgroup of patients, we considered improvement if the last value of CG-CrCl on PI monotherapy was 10% higher than the last value of CG-CrCl before switching to PI monotherapy. A multivariate logistic regression was constructed to identify factors associated to renal improvement after switching to bPI monotherapy. RESULTS: 64 patients included. The median (IQR) annual change in CG-CrCl during PI monotherapy was significantly lower than the median (IQR) annual change while exposed to TDF [-0.9 (-4.7 to +2.8) ml/min vs. -4 (-8 to -1) ml/min, p=0.001]. 44 patients experienced a rapid decline during TDF exposition. After switch to PI monotherapy, 15/44 (34%, 95% CI: 21-50%) had an improved CG-CrCl and 16/44 (36%, CI 23-52%) experienced a further decline in CG-CrCl. The only variable associated to CG-CrCl improvement was a more rapid CG-CrCl decline in the last year of exposure to TDF. CONCLUSION: Switching to PI monotherapy partially reversed CG-CrCl decrease associated to TDF use, especially in patients with a more rapid decline while receiving TDF.

The natural history of liver cirrhosis in HIV-hepatitis C virus-coinfected patients.

OBJECTIVE: To provide detailed information about the natural history of HIV-hepatitis C virus (HCV)-coinfected patients with cirrhosis. METHODS: Prospective cohort including 340 HIV-HCV-coinfected patients with compensated (n = 248) or decompensated (n = 92) cirrhosis. We evaluated predictors of survival and of first hepatic decompensation. RESULTS: The mortality rate for patients with decompensated and compensated cirrhosis was 27.14 deaths per 100 person-years [95% confidence interval (CI) 18.93-35.35] and 3.98 deaths per 100 person-years (95% CI 2.42-5.54), respectively. Rate of first hepatic decompensation in patients with compensated cirrhosis was 4.62 per 100 persons-years (95% CI 2.91-6.33). In the complete cohort, permanent HAART interruption during follow-up, CD4 cell count nadir and baseline Child-Pugh score (CPS) B or C were significantly associated with shorter survival. In patients with compensated cirrhosis factors significantly associated with decreased survival were having the first hepatic decompensation during follow-up, permanent HAART discontinuation, and CPS B and C at baseline. For patients with compensated cirrhosis, time since diagnosis of HCV infection, CPS B and C and permanent HAART discontinuation were significantly associated with the risk of first hepatic decompensation. Sustained viral response to anti-HCV therapy was not independently associated with better survival in patients with compensated cirrhosis. CONCLUSION: HIV-HCV-coinfected patients with cirrhosis have a relatively good 3-year survival (87%). In contrast, 2-year survival of patients with decompensated liver cirrhosis is only 50%. Three-year survival was mostly impacted by liver-related factors and HAART maintenance.

PPARß/δ activation blocks lipid-induced inflammatory pathways in mouse heart and human cardiac cells.

Owing to its high fat content, the classical Western diet has a range of adverse effects on the heart, including enhanced inflammation, hypertrophy, and contractile dysfunction. Proinflammatory factors secreted by cardiac cells, which are under the transcriptional control of nuclear factor-κB (NF-κB), may contribute to heart failure and dilated cardiomyopathy. The underlying mechanisms are complex, since they are linked to systemic metabolic abnormalities and changes in cardiomyocyte phenotype. Peroxisome proliferator-activated receptors (PPARs) are transcription factors that regulate metabolism and are capable of limiting myocardial inflammation and hypertrophy via inhibition of NF-κB. Since PPARß/δ is the most prevalent PPAR isoform in the heart, we analyzed the effects of the PPARß/δ agonist GW501516 on inflammatory parameters. A high-fat diet induced the expression of tumor necrosis factor-α, monocyte chemoattractant protein-1, and interleukin-6, and enhanced the activity of NF-κB in the heart of mice. GW501516 abrogated this enhanced proinflammatory profile. Similar results were obtained when human cardiac AC16 cells exposed to palmitate were coincubated with GW501516. PPARß/δ activation by GW501516 enhanced the physical interaction between PPARß/δ and p65, which suggests that this mechanism may also interfere NF-κB transactivation capacity in the heart. GW501516-induced PPARß/δ activation can attenuate the inflammatory response induced in human cardiac AC16 cells exposed to the saturated fatty acid palmitate and in mice fed a high-fat diet. This is relevant, especially taking into account that PPARß/δ has been postulated as a potential target in the treatment of obesity and the insulin resistance state.

The Role of Peroxisome Proliferator-Activated Receptor beta/delta on the Inflammatory Basis of Metabolic Disease.

The pathophysiology underlying several metabolic diseases, such as obesity, type 2 diabetes mellitus, and atherosclerosis, involves a state of chronic low-level inflammation. Evidence is now emerging that the nuclear receptor Peroxisome Proliferator-Activated Receptor (PPAR)beta/delta ameliorates these pathologies partly through its anti-inflammatory effects. PPARbeta/delta activation prevents the production of inflammatory cytokines by adipocytes, and it is involved in the acquisition of the anti-inflammatory phenotype of macrophages infiltrated in adipose tissue. Furthermore, PPARbeta/delta ligands prevent fatty acid-induced inflammation in skeletal muscle cells, avoid the development of cardiac hypertrophy, and suppress macrophage-derived inflammation in atherosclerosis. These data are promising and suggest that PPARbeta/delta ligands may become a therapeutic option for preventing the inflammatory basis of metabolic diseases.

Peroxisome proliferator-activated receptor (PPAR) beta/delta: a new potential therapeutic target for the treatment of metabolic syndrome.

Metabolic syndrome is defined as the clustering of multiple metabolic abnormalities, including abdominal obesity, dyslipidemia (high serum triglycerides and low serum HDL-cholesterol levels), glucose intolerance and hypertension. The pathophysiology underlying metabolic syndrome involves a complex interaction of crucial factors, but two of these, insulin resistance and obesity (especially visceral obesity), play a major role. The nuclear receptors Peroxisome Proliferator-Activated Receptors (PPAR)alpha and PPARgamma are therapeutic targets for hypertriglyceridemia and insulin resistance, respectively. Evidence is now emerging that the PPARbeta/delta; isotype is a potential pharmacological target for the treatment of disorders associated with metabolic syndrome. PPARbeta/delta; activation increases lipid catabolism in skeletal muscle, heart and adipose tissue and improves the serum lipid profile and insulin sensitivity in several animal models. In addition, PPARbeta/delta; ligands prevent weight gain and suppress macrophage-derived inflammation. These data are promising and indicate that PPARbeta/delta; ligands may become a therapeutic option for the treatment of metabolic syndrome. However, clinical trials in humans assessing the efficacy and safety of these drugs should confirm these promising perspectives in the treatment of the metabolic syndrome.

Atorvastatin prevents carbohydrate response element binding protein activation in the fructose-fed rat by activating protein kinase A.

UNLABELLED: High fructose intake contributes to the overall epidemic of obesity and metabolic disease. Here we examined whether atorvastatin treatment blocks the activation of the carbohydrate response element binding protein (ChREBP) in the fructose-fed rat. Fructose feeding increased blood pressure (21%, P < 0.05), plasma free fatty acids (59%, P < 0.01), and plasma triglyceride levels (129%, P < 0.001) compared with control rats fed standard chow. These increases were prevented by atorvastatin. Rats fed the fructose-rich diet showed enhanced hepatic messenger RNA (mRNA) levels of glycerol-3-phosphate acyltransferase (Gpat1) (1.45-fold induction, P < 0.05), which is the rate-limiting enzyme for the synthesis of triglycerides, and liver triglyceride content (2.35-fold induction, P < 0.001). Drug treatment inhibited the induction of Gpat1 and increased the expression of liver-type carnitine palmitoyltransferase 1 (L-Cpt-1) (128%, P < 0.01). These observations indicate that atorvastatin diverts fatty acids from triglyceride synthesis to fatty acid oxidation, which is consistent with the reduction in liver triglyceride levels (28%, P < 0.01) observed after atorvastatin treatment. The expression of Gpat1 is regulated by ChREBP and sterol regulatory element binding protein-1c (SREBP-1c). Atorvastatin treatment prevented fructose-induced ChREBP translocation and the increase in ChREBP DNA-binding activity while reducing SREBP-1c DNA-binding activity. Statin treatment increased phospho-protein kinase A (PKA), which promotes nuclear exclusion of ChREBP and reduces its DNA-binding activity. Human HepG2 cells exposed to fructose showed enhanced ChREBP DNA-binding activity, which was not observed in the presence of atorvastatin. Furthermore, atorvastatin treatment increased the CPT-I mRNA levels in these cells. Interestingly, both effects of this drug were abolished in the presence of the PKA inhibitor H89. CONCLUSION: These findings indicate that atorvastatin inhibits fructose-induced ChREBP activity and increases CPT-I expression by activating PKA.

Activation of peroxisome proliferator-activated receptor beta/delta inhibits lipopolysaccharide-induced cytokine production in adipocytes by lowering nuclear factor-kappaB activity via extracellular signal-related kinase 1/2.

OBJECTIVE: Chronic activation of the nuclear factor-kappaB (NF-kappaB) in white adipose tissue leads to increased production of pro-inflammatory cytokines, which are involved in the development of insulin resistance. It is presently unknown whether peroxisome proliferator-activated receptor (PPAR) beta/delta activation prevents inflammation in adipocytes. RESEARCH DESIGN AND METHODS AND RESULTS: First, we examined whether the PPARbeta/delta agonist GW501516 prevents lipopolysaccharide (LPS)-induced cytokine production in differentiated 3T3-L1 adipocytes. Treatment with GW501516 blocked LPS-induced IL-6 expression and secretion by adipocytes and the subsequent activation of the signal transducer and activator of transcription 3 (STAT3)-Suppressor of cytokine signaling 3 (SOCS3) pathway. This effect was associated with the capacity of GW501516 to impede LPS-induced NF-kappaB activation. Second, in in vivo studies, white adipose tissue from Zucker diabetic fatty (ZDF) rats, compared with that of lean rats, showed reduced PPARbeta/delta expression and PPAR DNA-binding activity, which was accompanied by enhanced IL-6 expression and NF-kappaB DNA-binding activity. Furthermore, IL-6 expression and NF-kappaB DNA-binding activity was higher in white adipose tissue from PPARbeta/delta-null mice than in wild-type mice. Because mitogen-activated protein kinase-extracellular signal-related kinase (ERK)1/2 (MEK1/2) is involved in LPS-induced NF-kappaB activation in adipocytes, we explored whether PPARbeta/delta prevented NF-kappaB activation by inhibiting this pathway. Interestingly, GW501516 prevented ERK1/2 phosphorylation by LPS. Furthermore, white adipose tissue from animal showing constitutively increased NF-kappaB activity, such as ZDF rats and PPARbeta/delta-null mice, also showed enhanced phospho-ERK1/2 levels. CONCLUSIONS: These findings indicate that activation of PPARbeta/delta inhibits enhanced cytokine production in adipocytes by preventing NF-kappaB activation via ERK1/2, an effect that may help prevent insulin resistance.

Peroxisome proliferator-activated receptor alpha down-regulation is associated with enhanced ceramide levels in age-associated cardiac hypertrophy.

We used an experimental murine model of accelerated aging, the senescence-accelerated mouse (SAM), to examine the effect of age-associated cardiac hypertrophy on peroxisome proliferator-activated receptor alpha (PPARalpha) expression and activity in the heart. Senescence-accelerated prone mice (SAM-P8) showed cardiac hypertrophy compared with senescence-accelerated resistant mice (SAM-R1). Furthermore, a decrease in PPARalpha messenger RNA (mRNA; 28% reduction, p<.001) and protein (47%, p<.05) levels and in PPAR DNA-binding activity was observed in SAM-P8 hearts. Increased protein-protein interaction between PPARalpha and the p65 subunit of nuclear factor-kappaB (NF-kappaB) was found, suggesting that this mechanism may prevent PPARalpha from binding to its response elements. The mRNA levels of PPARalpha target genes involved in fatty acid use were strongly suppressed in SAM-P8, which was consistent with the accumulation of ceramide in SAM-P8 hearts (2.5-fold induction, p<.05). These findings suggest that NF-kappaB activation in SAM-P8 heart prevents PPARalpha from binding to its response elements leading to changes in gene expression that may lead to ceramide accumulation in the aged heart.