RESUMEN
BACKGROUND: This study presents a comprehensive comparison between a marker-based motion capture system (MMC) and a video-based motion capture system (VMC) in the context of kinematic analysis using musculoskeletal models. OBJECTIVE: Focusing on joint angles, the study aimed to evaluate the accuracy of VMC as a viable alternative for biomechanical research. METHODS: Eighteen healthy subjects performed isolated movements with 17 joint degrees of freedom, and their kinematic data were collected using both an MMC and a VMC setup. The kinematic data were entered into the AnyBody Modelling System, which enables the calculation of joint angles. The mean absolute error (MAE) was calculated to quantify the deviations between the two systems. RESULTS: The results showed good agreement between VMC and MMC at several joint angles. In particular, the shoulder, hip and knee joints showed small deviations in kinematics with MAE values of 4.8∘, 6.8∘ and 3.5∘, respectively. However, the study revealed problems in tracking hand and elbow movements, resulting in higher MAE values of 13.7∘ and 27.7∘. Deviations were also higher for head and thoracic movements. CONCLUSION: Overall, VMC showed promising results for lower body and shoulder kinematics. However, the tracking of the wrist and pelvis still needs to be refined. The research results provide a basis for further investigations that promote the fusion of VMC and musculoskeletal models.
RESUMEN
BACKGROUND: Various rescue techniques are used for the prehospital transport of trauma patients. This study compares different techniques in terms of immobilization of the cervical spine and the rescue time. METHODS: A wireless motion capture system (Xsens Technologies, Enschede, The Netherlands) was used to record motion in three-dimensional space and the rescue time in a standardized environment. Immobilization was performed by applying different techniques through different teams of trained paramedics and physicians. All tests were performed on the set course, starting with the test person lying on the floor and ending with the test person lying on an ambulance cot ready to be loaded into an ambulance. Six different settings for rescue techniques were examined: rescue sheet with/without rigid cervical collar (P1S1, P1S0), vacuum mattress and scoop stretcher with/without rigid cervical collar (P2S1, P2S0), and long spinal board with/without rigid cervical collar (P3S1, P3S0). Four time intervals were defined: the time interval in which the rigid cervical collar is applied (T0), the time interval in which the test person is positioned on rescue sheet, vacuum mattress and scoop stretcher, or long spinal board (T1), the time interval in which the test person is carried to the ambulance cot (T2), and the time interval in which the ambulance cot is rolled to the ambulance (T3). An ANOVA was performed to compare the different techniques. RESULTS: During the simulated extrication procedures, a rigid cervical collar provided biomechanical stability at all angles with hardly any loss of time (mean angle ranges during T1: axial rotation P1S0 vs P1S1 p<0.0001, P2S0 vs P2S1 p<0.0001, P3S0 vs P3S1 p<0.0001; lateral bending P1S0 vs P1S1 p = 0.0263, P2S0 vs P2S1 p<0.0001, P3S0 vs P3S1 p<0.0001; flexion/extension P1S0 vs P1S1 p = 0.0023, P2S0 vs P2S1 p<0.0001). Of the three techniques examined, the scoop stretcher and vacuum mattress were best for reducing lateral bending in the frontal plane (mean angle ranges during T1: P2S1 vs P3S1 p = 0.0333; P2S0 vs P3S0 p = 0.0123) as well as flexion and extension in the sagittal plane (mean angle ranges during T2: P1S1 vs P2S1 p<0.0001; P1S0 vs P2S0 p<0.0001). On the other hand, the rescue sheet was clearly superior in terms of time (total duration P1S0 vs P2S0 p<0.001, P1S1 vs P2S1 p<0.001, P1S0 vs P3S0 p<0.001, P1S1 vs P3S1 p<0.001) but was always associated with significantly larger angular ranges of the cervical spine during the procedure. Therefore, the choice of technique depends on various factors such as the rescue time, the available personnel, as well as the severity of the suspected instability.
Asunto(s)
Inmovilización , Camillas , Humanos , Inmovilización/métodos , Captura de Movimiento , Vértebras Cervicales/lesiones , Rotación , Rango del Movimiento Articular , Fenómenos BiomecánicosRESUMEN
When mental stress and musculoskeletal loading interact, the risk for injury increases due to altered body kinematics and increased muscle tension. These changes can be detected with musculoskeletal models, and mental loading and stress must be analyzed at emotional, cognitive, and behavioral levels. To investigate these kinematic and loading changes under stress, competitive athletes were subjected to mental stress during highly dynamic movements, and musculoskeletal models were used to analyze the biomechanical loading. It was shown that under mental stress, independent of the subjective perception, a strong change in muscle forces can occur. Accordingly, competitive athletes should undergo screenings to assess individual movement patterns and promote general stress resilience.
Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Fútbol , Humanos , Fútbol/lesiones , Lesiones del Ligamento Cruzado Anterior/prevención & control , Movimiento/fisiología , MúsculosRESUMEN
BACKGROUND: Recommendations on the optimal preservation of 24 h urine for the metabolic work-up in urolithiasis patients are very heterogeneous. In case two such tests with different storage condition recommendations are being analysed, multiple collections would be needed, challenging especially elderly and very young patients. We therefore aimed to evaluate the stability of urine constituents under different storage conditions. MATERIAL AND METHODS: We collected urine samples from ten healthy volunteers and prepared aliquots to be stored either at room temperature or 4 °C. Some aliquots were preserved using hydrochloric acid prior to storage, some thereafter, some using the BD Urine preservation tube and some were not preserved at all. Storage duration was 0, 24, 48 or 72 h. In all samples calcium, magnesium, phosphorus, creatinine, oxalate, citrate and uric acid were measured and compared to the according reference sample. RESULTS: We could not find any significant deviation for any of the analytes and preanalytical treatment conditions compared to the associated reference sample. CONCLUSION: Preservation of 24 h urine for the metabolic evaluation in stone formers might not be necessary for sample storage up to 72 h.
Asunto(s)
Urolitiasis , Anciano , Calcio , Ácido Cítrico , Humanos , Concentración de Iones de Hidrógeno , Magnesio , Factores de Riesgo , Urolitiasis/diagnóstico , Urolitiasis/orinaRESUMEN
Purpose: Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Hence, this study investigated the musculoskeletal response of elite youth football players during highly dynamic movements under stress. The hypothesis is that mental stress reduces performance and changes the muscular forces exerted.Materials & methods: Twelve elite youth football players were subjected to mental stress while performing sports-specific change-of-direction movements. A modified version of the d2 attention test was used as stressor. The kinetics are computed using inverse dynamics. Running times and exerted forces of injury-prone muscles were analysed.Results: The stressor runs were rated more mentally demanding by the players (p = 0.006, rs = 0.37) with unchanged physical demand (p = 0.777, rs = 0.45). This resulted in 10% longer running times under stress (p < 0.001, d = -1.62). The musculoskeletal analysis revealed higher peak muscle forces under mental stress for some players but not for others.Discussion: The study shows that motion capture combined with musculoskeletal computation is suitable to analyse the effects of stress on athletes in highly dynamic movements. For the first time in football medicine, our data quantifies an association between mental stress with reduced football players' performance and changes in muscle force.
Asunto(s)
Fútbol Americano , Traumatismos de la Pierna , Carrera , Fútbol , Adolescente , Atletas , Fútbol Americano/lesiones , Humanos , Músculo Esquelético/lesiones , Fútbol/lesionesRESUMEN
Background: Laboratory overutilization is associated with diagnostic error and potential patient risk. We applied a demand management strategy in collaboration with the local Department of Cardiology to reduce the cardiac markers high-sensitive troponin T (hsTropT) and N-terminal pro brain natriuretic peptide (NTproBNP) in laboratory ordering profiles (LOPs). The present study aimed to retrospectively evaluate the implemented strategies. Methods: Strategies included educational measures and evidence-guided, active test de-selection from all cardiology ward LOPs, and/or permanent removal from LOPs. Tests remained available at all times. We evaluated overutilization by reductions in monthly orders, and assessed differences in 30-day all-cause readmission rate and length of patients' hospital stay. Results: Overall, we observed a mean reduction of 66.1% ± 7.6% (n = 277 ± 31) in hsTropT tests. Educational measures effectively reduced NTproBNP orders by 52.8% ± 17.7% (n = 60 ± 20). Permanent removal of tests from LOPs additionally decreased orders to a final extent of 75.8% ± 8.0% (n = 322 ± 31) in NTproBNP tests. The 30-day readmission rate and overall length of hospital stay did not increase. Conclusions: Our results indicate that cardiac markers in routine care are subject to extensive overutilization when used within LOPs. Educational measures are an effective strategy to overcome the overutilization of cardiac markers but may be more effective when combined with the removal of cardiac markers from LOPs.
Asunto(s)
Pruebas Diagnósticas de Rutina/economía , Cardiopatías/sangre , Unidades Hospitalarias , Biomarcadores/sangre , Humanos , Péptido Natriurético Encefálico/sangre , Fragmentos de Péptidos/sangre , Estudios Retrospectivos , Troponina TRESUMEN
PPARGC1A encodes a transcriptional co-activator also termed peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1-alpha (PGC-1α) which orchestrates multiple transcriptional programs. We have recently identified CNS-specific transcripts that are initiated far upstream of the reference gene (RG) promoter. The regulation of these isoforms may be relevant, as experimental and genetic studies implicated the PPARGC1A locus in neurodegenerative diseases. We therefore studied cis- and trans-regulatory elements activating the CNS promoter in comparison to the RG promoter in human neuronal cell lines. A naturally occurring variable guanidine thymidine (GT) repeat polymorphism within a microsatellite region in the proximal CNS promoter increases promoter activity in neuronal cell lines. Both the RG and the CNS promoters are activated by ESRRA, and the PGC-1α isoforms co-activate ESRRA on their own promoters suggesting an autoregulatory feedback loop. The proximal CNS, but not the RG, promoter is induced by FOXA2 and co-activated by PGC-1α resulting in robust activation. Furthermore, the CNS, but not the RG, promoter is targeted by the canonical hypoxia response involving HIF1A. Importantly, the transactivation by HIF1A is modulated by the size of the GT polymorphism. Increased expression of CNS-specific transcripts in response to hypoxia was observed in an established rat model, while RG transcripts encoding the full-length reference protein were not increased. These results suggest a role of the CNS region of the PPARGC1A locus in ischemia and warrant further studies in humans as the activity of the CNS promoter as well as its induction by hypoxia is subject to inter-individual variability due to the GT polymorphism.
Asunto(s)
Sistema Nervioso Central/metabolismo , Regulación de la Expresión Génica , Hipoxia/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/genética , Polimorfismo Genético , Secuencias Repetitivas de Ácidos Nucleicos/genética , Animales , Secuencia de Bases , Isquemia Encefálica/genética , Isquemia Encefálica/patología , Línea Celular , Ciclopirox/farmacología , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Masculino , Especificidad de Órganos/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Regiones Promotoras Genéticas , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas WistarRESUMEN
Background Published evidence on the risk of additive carryover during phlebotomy remains elusive. We aimed to assess potential carryover of citrated and heparinized blood and the relative volume needed to bias clinical chemistry and coagulation tests. Methods We simulated standardized phlebotomies to quantify the risk of carryover of citrate and heparin additives in distilled water, using sodium and lithium as surrogates. We also investigated the effects of contamination of heparinized blood samples with increasing volumes of citrated blood and pure citrate on measurements of sodium, potassium, chloride, magnesium, total and ionized calcium and phosphate. Likewise, we studied the effects of contamination of citrated blood samples with increasing volumes of heparinized blood on heparin (anti-Xa) activity, lithium, activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT). We interpreted these results based on measurement deviations beyond analytical, biological and clinical significance. Results Standardized phlebotomy simulations revealed no significant differences in concentration of surrogate markers. Clinically significant alterations were observed after contamination of heparinized blood samples with volumes of citrated blood beyond 5-50 µL for ionized calcium and beyond 100-1000 µL for sodium, chloride and total calcium. Investigations of pure citrate carryover revealed similar results at somewhat lower volumes. Heparinized blood carryover showed clinically significant interference of coagulation testing at volumes beyond 5-100 µL. Conclusions Our results suggest that during a standardized phlebotomy, heparin or citrate contamination is highly unlikely. However, smaller volumes are sufficient to severely alter test results when deviating from phlebotomy guidelines.
Asunto(s)
Recolección de Muestras de Sangre/métodos , Ácido Cítrico/análisis , Heparina/análisis , Anticoagulantes , Coagulación Sanguínea/efectos de los fármacos , Pruebas de Coagulación Sanguínea/métodos , Citratos , Ácido Cítrico/sangre , Contaminación de Equipos/prevención & control , Heparina/sangre , Humanos , Tiempo de Tromboplastina Parcial , Flebotomía/métodos , Flebotomía/normas , Fase Preanalítica/métodos , Tiempo de Protrombina , Tiempo de TrombinaRESUMEN
BACKGROUND: Marinobufagenin (MBG) is an endogenous cardiotonic steroid (CTS) that inhibits the Na+/K+-ATPase. Human MBG is significantly increased in end-stage renal disease and immunization against MBG attenuates cardiovascular fibrosis in a rat model of uremic cardiomyopathy. Mineralocorticoid antagonists (MRA) block MBG binding sites and decrease proteinuria in chronic kidney disease (CKD) patients. We therefore aimed to investigate the association of MBG and albuminuria, as a marker of renal damage, as well as MBG and decline of glomerular filtration rate (GFR). METHODS: The Graz endocrine causes of hypertension (GECOH) study is a single center study of adults routinely referred for screening of endocrine hypertension. Plasma MBG was measured by an enzyme-linked immunoassay, and in a post-hoc analysis, follow-up creatinine levels were obtained. Patients with proteinuria >3.5g/day at baseline were excluded from further evaluation. RESULTS: We measured MBG concentrations in 40 hypertensive subjects and excluded one patient due to pre-existing proteinuria. Plasma MBG was significantly correlated with albuminuria (Spearman ρ = .357; p = .028) and proteinuria (ρ = .336; p = .039). In linear regression analysis, the association remained significant after adjustment for age, sex, and BMI (ß = .306; p = .036), and for mean systolic blood pressure (ß = .352; p = .034). In follow-up analyses (N = 30), MBG was significantly associated with decline in GFR after adjustment for time-to-follow-up (ß = -.374; p = .042). CONCLUSION: The findings suggest that MBG plasma concentrations were associated with albuminuria as well as decline in kidney function. Whether MBG predicts hard renal endpoints warrants further investigations.
Asunto(s)
Bufanólidos/sangre , Tasa de Filtración Glomerular/fisiología , Hipertensión/sangre , Hipertensión/fisiopatología , Adulto , Anciano , Albuminuria/sangre , Albuminuria/fisiopatología , Animales , Biomarcadores/sangre , Cardiotónicos/sangre , Inhibidores Enzimáticos/sangre , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Proteinuria/sangre , Proteinuria/fisiopatología , Ratas , Insuficiencia Renal Crónica/sangre , Insuficiencia Renal Crónica/fisiopatologíaRESUMEN
BACKGROUND: Inappropriate utilization of laboratory resources is an increasing concern especially in high-throughput facilities. Until now, no reliable information has been published addressing to which extent laboratory results are actually used for clinical decision-making. Therefore, we aimed to close this gap using a novel retrospective approach including a survey of clinicians and nurses. METHODS: We retrospectively evaluated the number of re-orders for potassium (K), lactate dehydrogenase (LD), aspartate-aminotransferase (AST), activated partial thromboplastin-time (APTT) and prothrombin-time/INR (PT/INR), after the initial order had to be cancelled due to preanalytical non-conformities. We analyzed subgroups regarding time to re-order, ward and sample priority (urgent vs. routine). Subsequently, we surveyed clinicians and nurses, asking for their estimate of the amount of failed re-orders as well as for possible reasons. RESULTS: From initially cancelled tests, only ~20% of K, LD, AST and ~30% of APTT and PT/INR tests were re-ordered within 24â¯h. 70% of the investigated clinical chemistry and 60% of coagulation tests were re-ordered one week after cancellation or not at all. Survey participants quite accurately estimated these numbers. Routine laboratory panels, short stay of out-patients, obsolete test results and avoiding additional phlebotomies were the main reasons for not re-ordering cancelled tests. CONCLUSIONS: Overall, 60-70% of test results in the investigated assays ordered in a high throughput laboratory are potentially inappropriate or of doubtful clinically importance. Although clinicians and nurses are aware of this situation, it is the duty of laboratory specialists to overcome overutilization in close collaboration with all involved healthcare workers.
Asunto(s)
Análisis Químico de la Sangre , Hospitales , Uso Excesivo de los Servicios de Salud , Femenino , Humanos , Masculino , Estudios RetrospectivosRESUMEN
NADPH oxidases of human cells are not only functional in defense against invading microorganisms and for oxidative reactions needed for specialized biosynthetic pathways but also during the past few years have been established as signaling modules. It has been shown that human Nox4 is expressed in most somatic cell types and produces hydrogen peroxide, which signals to remodel the actin cytoskeleton. This correlates well with the function of Yno1, the only NADPH oxidase of yeast cells. Using two established tumor cell lines, which are derived from hepatic and neuroblastoma tumors, respectively, we are showing here that in both tumor models Nox4 is expressed in the ER (like the yeast NADPH oxidase), where according to published literature, it produces hydrogen peroxide. Reducing this biochemical activity by downregulating Nox4 transcription leads to loss of F-actin stress fibers. This phenotype is reversible by adding hydrogen peroxide to the cells. The effect of the Nox4 silencer RNA is specific for this gene as it does not influence the expression of Nox2. In the case of the SH-SY5Y neuronal cell line, Nox4 inhibition leads to loss of cell mobility as measured in scratch assays. We propose that inhibition of Nox4 (which is known to be strongly expressed in many tumors) could be studied as a new target for cancer treatment, in particular for inhibition of metastasis.
RESUMEN
OBJECTIVES: Regular aerobic exercise provides beneficial effects on human health and reduces all-cause mortality. Aerobic exercise has profound metabolic effects, and specific metabolites may reflect physiological changes. We aimed to identify endogenous metabolites that distinguish the trained from the untrained state to increase the spectrum of analytes amenable for hypothesis testing and to expand understanding of putative beneficial pathways. DESIGN: Cross sectional laboratory repeated measures study. METHODS: Exercise testing was performed in 37 healthy male participants and serum samples were obtained before and after completion of a ten-week standardized exercise program. Samples were analyzed for routine clinical parameters and for 188 endogenous metabolites by LC-MS/MS. RESULTS: Indicating the effectiveness of the intervention program, parameters of sport physiology were different after training. After correcting for multiple testing, serum concentrations of several metabolites differed between the trained and untrained state. Serine and glutamate decreased in response to exercise, whereas sarcosine and kynurenine increased. Phosphatidylcholines showed a mixed response in that four species increased and three decreased. However, all seven lysophosphatidylcholines and all four plasmalogens that differed between the trained and untrained state, increased. One short-chain acylcarnitine also decreased. In receiver operator characteristics analyses, sarcosine displayed the highest AUC value (0.839; 95% CI: 0.734-0.926) in discriminating the pre- from the post-trained state. CONCLUSIONS: Our study detected metabolites that clearly differentiate the trained from the untrained state. These metabolites may be targeted in mechanistic studies to understand underlying biochemical pathways and could serve to improve the design, monitoring and individualization of training programs.
Asunto(s)
Aminoácidos/sangre , Aminas Biogénicas/sangre , Carnitina/análogos & derivados , Ejercicio Físico/fisiología , Fosfolípidos/sangre , Biomarcadores/sangre , Carnitina/sangre , Cromatografía Liquida , Estudios Transversales , Humanos , Masculino , Persona de Mediana Edad , Espectrometría de Masas en TándemRESUMEN
OBJECTIVE: Elevated serum ferritin has been linked to type 2 diabetes (T2D) and adverse health outcomes in subjects with the Metabolic Syndrome (MetS). As the mechanisms underlying the negative impact of excess iron have so far remained elusive, we aimed to identify potential links between iron homeostasis and metabolic pathways. METHODS: In a cross-sectional study, data were obtained from 163 patients, allocated to one of three groups: (1) lean, healthy controls (n = 53), (2) MetS without hyperferritinemia (n = 54) and (3) MetS with hyperferritinemia (n = 56). An additional phlebotomy study included 29 patients with biopsy-proven iron overload before and after iron removal. A detailed clinical and biochemical characterization was obtained and metabolomic profiling was performed via a targeted metabolomics approach. RESULTS: Subjects with MetS and elevated ferritin had higher fasting glucose (p < 0.001), HbA1c (p = 0.035) and 1 h glucose in oral glucose tolerance test (p = 0.002) compared to MetS subjects without iron overload, whereas other clinical and biochemical features of the MetS were not different. The metabolomic study revealed significant differences between MetS with high and low ferritin in the serum concentrations of sarcosine, citrulline and particularly long-chain phosphatidylcholines. Methionine, glutamate, and long-chain phosphatidylcholines were significantly different before and after phlebotomy (p < 0.05 for all metabolites). CONCLUSIONS: Our data suggest that high serum ferritin concentrations are linked to impaired glucose homeostasis in subjects with the MetS. Iron excess is associated to distinct changes in the serum concentrations of phosphatidylcholine subsets. A pathway involving sarcosine and citrulline also may be involved in iron-induced impairment of glucose metabolism.
Asunto(s)
Glucosa/metabolismo , Hierro/metabolismo , Adulto , Glucemia/metabolismo , Citrulina/sangre , Citrulina/metabolismo , Estudios Transversales , Diabetes Mellitus Tipo 2/metabolismo , Femenino , Ferritinas/análisis , Ferritinas/sangre , Ferritinas/metabolismo , Prueba de Tolerancia a la Glucosa , Homeostasis , Humanos , Resistencia a la Insulina/fisiología , Hierro/sangre , Masculino , Síndrome Metabólico/metabolismo , Metabolómica/métodos , Persona de Mediana Edad , Obesidad/sangre , Sarcosina/sangre , Sarcosina/metabolismoRESUMEN
OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is closely linked to obesity; however, 5-8% of lean subjects also have evidence of NAFLD. We aimed to investigate clinical, genetic, metabolic and lifestyle characteristics in lean Caucasian subjects with NAFLD. METHODS: Data from 187 subjects allocated to one of the three groups according to body mass index (BMI) and hepatic steatosis on ultrasound were obtained: lean healthy (BMI≤25 kg/m2, no steatosis, N=71), lean NAFLD (BMI≤25 kg/m2, steatosis, N=55), obese NAFLD (BMI≥30 kg/m2, steatosis; N=61). All subjects received a detailed clinical and laboratory examination including oral glucose tolerance test. The serum metabolome was assessed using the Metabolomics AbsoluteIDQ p180 kit (BIOCRATES Life Sciences). Genotyping for single-nucleotide polymorphisms (SNPs) associated with NAFLD was performed. RESULTS: Lean NAFLD subjects had fasting insulin concentrations similar to lean healthy subjects but had markedly impaired glucose tolerance. Lean NAFLD subjects had a higher rate of the mutant PNPLA3 CG/GG variant compared to lean controls (P=0.007). Serum adiponectin concentrations were decreased in both NAFLD groups compared to controls (P<0.001 for both groups) The metabolomics study revealed a potential role for various lysophosphatidylcholines (lyso-PC C18:0, lyso-PC C17:0) and phosphatidylcholines (PCaa C36:3; false discovery rate (FDR)-corrected P-value<0.001) as well as lysine, tyrosine, and valine (FDR<0.001). CONCLUSIONS: Lean subjects with evidence of NAFLD have clinically relevant impaired glucose tolerance, low adiponectin concentrations and a distinct metabolite profile with an increased rate of PNPLA3 risk allele carriage.
Asunto(s)
Adiponectina/metabolismo , Intolerancia a la Glucosa/metabolismo , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Obesidad/metabolismo , Adulto , Anciano , Alelos , Índice de Masa Corporal , Estudios de Casos y Controles , Femenino , Genotipo , Intolerancia a la Glucosa/epidemiología , Humanos , Insulina/metabolismo , Resistencia a la Insulina , Lipasa/genética , Hígado/diagnóstico por imagen , Hígado/metabolismo , Lisina/metabolismo , Lisofosfatidilcolinas/metabolismo , Masculino , Proteínas de la Membrana/genética , Metabolómica , Persona de Mediana Edad , Enfermedad del Hígado Graso no Alcohólico/complicaciones , Enfermedad del Hígado Graso no Alcohólico/diagnóstico por imagen , Enfermedad del Hígado Graso no Alcohólico/epidemiología , Obesidad/complicaciones , Fosfatidilcolinas/metabolismo , Polimorfismo de Nucleótido Simple , Tirosina/metabolismo , Ultrasonografía , Valina/metabolismo , Población BlancaRESUMEN
BACKGROUND: Hemeoxygenase-1 (HO-1) has recently been identified as a major driver of metaflammation and obesity-related insulin resistance (IR). Drug-induced IR increases cardiovascular risk within the HIV-1-infected population receiving antiretroviral therapy (ART). We therefore investigated a possible role of HO-1 in ART-induced IR. METHODS: Effects of HIV-1 protease inhibitor ritonavir and integrase inhibitor raltegravir (RAL) on expression levels of HO-1 and proinflammatory cytokines, including interleukin 1ß (IL-1ß), IL-6, IL-8, tumor necrosis factor-α (TNFα), chemokine (C-C motif) ligand 5 (CCL5), and monocyte chemotactic protein 1 (MCP-1), were studied in monocyte and hepatocyte cell lines. Plasma levels of HO-1 and inflammatory markers were measured in insulin-resistant and insulin-sensitive HIV-1-infected patients under ART and seronegative controls. RESULTS: We show that, in contrast to RAL, ritonavir treatment significantly increases mRNA expression levels of HO-1, IL-8, TNFα, CCL5, and MCP-1 in vitro in a dose-dependent manner. HO-1 plasma levels were significantly higher in insulin-resistant compared to insulin-sensitive patients on ritonavir-boosted ART (lopinavir/ritonavir group: 3.90 ± 1.15 vs 2.56 ± 1.07 ng/mL, P < 0.005 and darunavir/ritonavir group: 3.16 ± 1.37 vs 2.28 ± 1.23 U/mL, P < 0.05) and were correlated with expression levels of TNFα in individuals on ritonavir-boosted ART (lopinavir/ritonavir group: r = 0.108, P < 0.05 and darunavir/ritonavir group: r = 0.221, P < 0.05) but not in HIV-1-infected individuals receiving RAL or in seronegative controls. IMPLICATIONS: HIV-1-infected patients on stable ART are often faced with non-AIDS-related metabolic comorbidities, increasing their individual cardiovascular risk. Here, we provide insight into a novel mechanism of ritonavir-induced IR involving proinflammatory properties of HO-1. Our initial observations might also provide prognostic value in the future to identify patients at risk for the development type 2 diabetes mellitus.
Asunto(s)
Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/efectos adversos , Hemo-Oxigenasa 1/análisis , Resistencia a la Insulina , Ritonavir/efectos adversos , Línea Celular , Citocinas/análisis , Perfilación de la Expresión Génica , Infecciones por VIH/virología , Inhibidores de la Proteasa del VIH/administración & dosificación , VIH-1/aislamiento & purificación , Hepatocitos/enzimología , Hepatocitos/inmunología , Humanos , Monocitos/enzimología , Monocitos/inmunología , Ritonavir/administración & dosificaciónRESUMEN
The genomic region ~500 kb upstream of IRS1 has been implicated in insulin resistance, type 2 diabetes, adverse lipid profile, and cardiovascular risk. To gain further insight into this chromosomal region, we typed four SNPs in a cross-sectional cohort and subjects with type 2 diabetes recruited from the same geographic region. From 16 possible haplotypes, 6 haplotypes with frequencies >0.01 were observed. We identified one haplotype that was protective against insulin resistance (determined by HOMA-IR and fasting plasma insulin levels), type 2 diabetes, an adverse lipid profile, increased C-reactive protein, and asymptomatic atherosclerotic disease (assessed by intima media thickness of the common carotid arteries). BMI and total adipose tissue mass as well as visceral and subcutaneous adipose tissue mass did not differ between the reference and protective haplotypes. In 92 subjects, we observed an association of the protective haplotype with higher skeletal muscle mRNA levels of LOC646736, which is located in the same haplotype block as the informative SNPs and is mainly expressed in skeletal muscle, but only at very low levels in liver or adipose tissues. These data suggest a role for LOC646736 in human insulin resistance and warrant further studies on the functional effects of this locus.
Asunto(s)
Aterosclerosis/complicaciones , Diabetes Mellitus Tipo 2/genética , Angiopatías Diabéticas/genética , Proteínas Sustrato del Receptor de Insulina/genética , Resistencia a la Insulina , Músculo Esquelético/metabolismo , Regiones no Traducidas 5' , Enfermedades Asintomáticas , Aterosclerosis/genética , Aterosclerosis/metabolismo , Aterosclerosis/patología , Austria , Estudios de Casos y Controles , Estudios de Cohortes , Estudios Transversales , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Angiopatías Diabéticas/metabolismo , Angiopatías Diabéticas/patología , Resistencia a la Enfermedad , Dislipidemias/complicaciones , Dislipidemias/genética , Dislipidemias/metabolismo , Dislipidemias/patología , Femenino , Estudios de Asociación Genética , Haplotipos , Humanos , Proteínas Sustrato del Receptor de Insulina/metabolismo , Masculino , Persona de Mediana Edad , Músculo Esquelético/patología , Polimorfismo de Nucleótido Simple , ARN Mensajero/metabolismoRESUMEN
Mutual clinical and molecular interactions between iron and glucose metabolism have been reported. We aimed to investigate a potential effect of glucose on iron homeostasis. We found that serum iron concentrations gradually decreased over 180 min after the administration of 75 g of glucose from 109.8 ± 45.4 mg/L to 94.4 ± 40.4 mg/L (P<.001; N=40) but remained unchanged in control subjects receiving tap water (N=21). Serum hepcidin, the key iron regulatory hormone which is mainly derived from hepatocytes but also expressed in pancreatic ß-cells, increased within 120 min after glucose ingestion from 19.7 ± 9.9 nmol/L to 31.4 ± 21.0 nmol/L (P<.001). In cell culture, glucose induced the secretion of hepcidin and insulin into the supernatant of INS-1E cultures, but did not change the amount of hepcidin detectable in the hepatocyte cell culture HepG2. We additionally confirmed the expression of hepcidin in a human islet cell preparation. These results suggest that glucose acts as a regulator of serum iron concentrations, most likely by triggering the release of hepcidin from ß-cells.
Asunto(s)
Péptidos Catiónicos Antimicrobianos/metabolismo , Glucosa/metabolismo , Hierro/sangre , Adulto , Animales , Péptidos Catiónicos Antimicrobianos/genética , Células Cultivadas , Femenino , Glucosa/farmacología , Prueba de Tolerancia a la Glucosa , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Hepcidinas , Homeostasis/efectos de los fármacos , Humanos , Células Secretoras de Insulina/efectos de los fármacos , Células Secretoras de Insulina/metabolismo , Insulinoma/tratamiento farmacológico , Insulinoma/metabolismo , Masculino , Persona de Mediana Edad , RatasRESUMEN
PGC-1α has been implicated in the pathogenesis of neurodegenerative disorders. Several single-nucleotide polymorphisms (SNPs) located in two separate haplotype blocks of PPARGC1A have shown associations with Huntington's disease (HD) and Parkinson's disease, but causative SNPs have not been identified. One SNP (rs7665116) was located in a highly conserved 233 bp region of intron 2. To determine whether rs7665116 is located in an alternative exon, we performed 5'-RLM-RACE from exon 3 and discovered multiple new transcripts that initiated from a common novel promoter located 587 kb upstream of exon 2, but did not contain the conserved region harboring rs7665116. Using real-time polymerase chain reaction, RNase protection assays and northern blotting, we show that the majority of these transcripts are brain specific and are at least equally or perhaps more abundant than the reference sequence PPARGC1A transcripts in whole brain. Two main transcripts containing independent methionine start codons encode full-length brain-specific PGC-1α proteins that differ only at their N-termini (NTs) from PGC-1α, encoded by the reference sequence. Additional truncated isoforms containing these NTs that are similar to NT-PGC-1α exist. Other transcripts may encode potential dominant negative forms, as they are predicted to lack the second LXXLL motif that serves as an interaction site for several nuclear receptors. Furthermore, we show that the new promoter is active in neuronal cell lines and describe haplotypes encompassing this region that are associated with HD age of onset. The discovery of such a large PPARGC1A genomic locus and multiple isoforms in brain warrants further functional studies and may provide new tissue-specific targets for treating neurodegenerative diseases.
Asunto(s)
Encéfalo/metabolismo , Genoma Humano , Proteínas de Choque Térmico/genética , Enfermedad de Huntington/epidemiología , Enfermedad de Huntington/genética , Factores de Transcripción/genética , Edad de Inicio , Exones , Genómica , Proteínas de Choque Térmico/metabolismo , Humanos , Intrones , Datos de Secuencia Molecular , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Factores de Transcripción/metabolismoRESUMEN
OBJECTIVE: Genetic studies implicated upstream stimulatory factor 1 (USF1) in familial combined hyperlipidemia because the rs2073658 minor allele was associated with reduced risk of familial combined hyperlipidemia and related disorders. The molecular mechanisms whereby rs2073658 influences trait expression have remained elusive. METHODS AND RESULTS: Plasma lipids, rs2073658 genotypes (N=372), and hepatic transcript levels (N=96) of USF1 and genes involved in hepatic lipoprotein production were determined in obese subjects. The rs2073658 minor allele was associated with reduced plasma triglycerides (TGs) (P<0.001), hepatic USF1 (P<0.01), and microsomal TG transfer protein transcript levels (P<0.05). Functional studies in human hepatocellular carcinoma cells showed that rs2073658 is located in a forkhead box A2 (FOXA2) binding site and that major allele constructs displayed higher transcriptional activity than minor allele constructs. Knockdown of FOXA2 reduced the activity of major, but not minor allele constructs. Furthermore, an interaction between hepatic FOXA2 transcript levels and rs2073658 minor allele carrier status on hepatic USF1 transcript levels was observed in vivo (P<0.05). USF1 activated the transcription of FOXA2 and FOXA2 strongly activated the transcription of microsomal TG transfer protein. CONCLUSIONS: A feed-forward loop comprising activation of USF1 transcription by FOXA2 and activation of FOXA2 transcription by USF1, driving microsomal TG transfer protein expression, is modulated by rs2073658. Hence, rs2073658 likely influences hepatic TG secretion.
Asunto(s)
Hiperlipidemia Familiar Combinada/genética , Hígado/metabolismo , Obesidad/genética , Polimorfismo de Nucleótido Simple , Factores Estimuladores hacia 5'/genética , Adulto , Anciano , Análisis de Varianza , Austria , Sitios de Unión , Proteínas Portadoras/metabolismo , Distribución de Chi-Cuadrado , Retroalimentación Fisiológica , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Células Hep G2 , Factor Nuclear 3-beta del Hepatocito/genética , Factor Nuclear 3-beta del Hepatocito/metabolismo , Humanos , Hiperlipidemia Familiar Combinada/sangre , Modelos Lineales , Desequilibrio de Ligamiento , Masculino , Persona de Mediana Edad , Obesidad/sangre , Fenotipo , Regiones Promotoras Genéticas , Interferencia de ARN , ARN Mensajero/metabolismo , Activación Transcripcional , Transfección , Triglicéridos/sangreRESUMEN
Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) is a transcriptional coactivator that contributes to the regulation of numerous transcriptional programs including the hepatic response to fasting. Mechanisms at transcriptional and post-transcriptional levels allow PGC-1α to support distinct biological pathways. Here we describe a novel human liver-specific PGC-1α transcript that results from alternative promoter usage and is induced by FOXO1 as well as glucocorticoids and cAMP-response element-binding protein signaling but is not present in other mammals. Hepatic tissue levels of novel and wild-type transcripts were similar but were only moderately associated (p < 0.003). Novel mRNA levels were associated with a polymorphism located in its promoter region, whereas wild-type transcript levels were not. Furthermore, hepatic PCK1 mRNA levels exhibited stronger associations with the novel than with the wild-type transcript levels. Except for a deletion of 127 amino acids at the N terminus, the protein, termed L-PGC-1α, is identical to PGC-1α. L-PGC-1α was localized in the nucleus and showed coactivation properties that overlap with those of PGC-1α. Collectively, our data support a role of L-PGC-1α in gluconeogenesis, but functional differences predicted from the altered structure suggest that L-PGC-1α may have arisen to adapt PGC-1α to more complex metabolic pathways in humans.