The ghrelin O-acyltransferase-ghrelin system reduces TNF-α-induced apoptosis and autophagy in human visceral adipocytes.

AIMS/HYPOTHESIS: Proinflammatory and proapoptotic cytokines such as TNF-α are upregulated in human obesity. We evaluated the association between ghrelin isoforms (acylated and desacyl ghrelin) and TNF-α in obesity and obesity-associated type 2 diabetes, as well as the potential role of ghrelin in the control of apoptosis and autophagy in human adipocytes. METHODS: Plasma concentrations of the ghrelin isoforms and TNF-α were measured in 194 participants. Ghrelin and ghrelin O-acyltransferase (GOAT) levels were analysed by western-blot, immunohistochemistry and real-time PCR in 53 biopsies of human omental adipose tissue. We also determined the effect of acylated and desacyl ghrelin (10 to 1,000 pmol/l) on TNF-α-induced apoptosis and autophagy-related molecules in omental adipocytes. RESULTS: Circulating concentrations of acylated ghrelin and TNF-α were increased, whereas desacyl ghrelin levels were decreased in obesity-associated type 2 diabetes. Ghrelin and GOAT were produced in omental and subcutaneous adipose tissue. Visceral adipose tissue from obese patients with type 2 diabetes showed higher levels of GOAT, increased adipocyte apoptosis and increased expression of the autophagy-related genes ATG5, BECN1 and ATG7. In differentiating human omental adipocytes, incubation with acylated and desacyl ghrelin reduced TNF-α-induced activation of caspase-8 and caspase-3, and cell death. In addition, acylated ghrelin reduced the basal expression of the autophagy-related genes ATG5 and ATG7, while desacyl ghrelin inhibited the TNF-α-induced increase of ATG5, BECN1 and ATG7 expression. CONCLUSIONS/INTERPRETATION: Apoptosis and autophagy are upregulated in human visceral adipose tissue of patients with type 2 diabetes. Acylated and desacyl ghrelin reduce TNF-α-induced apoptosis and autophagy in human visceral adipocytes.

Correlation between serum content of the main COPs (cholesterol oxidation products) from autoxidation and cardiovascular risk factors.

BACKGROUND/AIMS: Risk factors for cardiovascular disease (CVD) have been proven to be associated with an increased oxidative stress. Several studies have considered cholesterol oxidation products (COPs) as specific in vivo markers of oxidative stress. The aim of this study was to investigate the association between the levels of COPs derived from autoxidation processes and established cardiovascular risk factors, comparing the levels of serum COPs in subjects with or without showing values out of the reference ranges. METHODS: It was a cross-sectional study in which 88 subjects were recruited and individual and total COPs from autoxidation origin was analyzed in serum by GC-MS. The simultaneous correlation of COPs with different CVD risk factors have been analyzed. RESULTS AND DISCUSSION: A great variability of total COPs concentrations were found. Subjects presented total COPs values from 0.091 to 2.052 µg/mL. Total COPs were significantly higher (p < 0.05) in patients with hypertriglycerolemia, hypertension, diabetes and overweight/ obesity status compared to those subjects who did not present those CVD risk factors. Moreover, 7α and 7ß hydroxycholesterol and 7-ketocholesterol were significantly higher (p < 0.05) in patients with hypertension and diabetes. No significant differences in total COPs were found between patients with and without hypercholesterolemia. CONCLUSIONS: The obtained results showed that the analyzed COPs correlate well with at least 4 out of 6 risk factors of development of CVD.

Correlation between serum content of the main COPs (cholesterol oxidationproducts) from autoxidation and cardiovascular risk factors / Correlación entre los productos de oxidación de colesterol (COPs) formados por autooxidación y factores de riesgo cardiovascular

Background/aims: Risk factors for cardiovascular disease (CVD) have been proven to be associated with an increased oxidative stress. Several studies have considered cholesterol oxidation products (COPs) as specific in vivo markers of oxidative stress. The aim of this study was to investigate the association between the levels of COPs derived from autoxidation processes and established cardiovascular risk factors, comparing the levels of serum COPs in subjects with or without showing values out of the reference ranges. Methods: It was a cross-sectional study in which 88 subjects were recruited and individual and total COPs from autoxidation origin was analyzed in serum by GC-MS. The simultaneous correlation of COPs with different CVD risk factors have been analyzed. Results and discussion: A great variability of total COPs concentrations were found. Subjects presented total COPs values from 0.091 to 2.052 μg/mL. Total COPs were significantly higher (p < 0.05) in patients with hyper-triglycerolemia, hypertension, diabetes and overweight/ obesity status compared to those subjects who did not present those CVD risk factors. Moreover, 7α and 7β hydroxycholesterol and 7-ketocholesterol were significantly higher (p < 0.05) in patients with hypertension and diabetes. No significant differences in total COPs were found between patients with and without hypercholes-terolemia. Conclusions: The obtained results showed that the analyzed COPs correlate well with at least 4 out of 6 risk factors of development of CVD (AU)

Introducción: Se ha demostrado que los factores de riesgo cardiovascular están estrechamente asociados con un elevado nivel de estrés oxidativo. Varios estudios consideran a los productos de oxidación del colesterol (COPs) como marcadores específicos in vivo de estrés oxidativo. El objetivo de este trabajo fue estudiar la asociación entre los niveles de COPs derivados de procesos de autooxidación de colesterol y factores de riesgo cardiovascular, comparando el contenido sérico de COPs en sujetos afectados o no por dichos factores. Métodos: Se trata de un estudio transversal en el que se reclutaron 88 personas a las que se analizó el perfil de óxidos de colesterol en suero procedentes de autooxidación, por cromatografía de gases-espectrometría de masas. Se valoró la correlación de los niveles de COPs con diferentes factores de riesgo cardiovascular. Resultados y discusión: Se encontró una gran variabilidad en el contenido en COPs totales, observándose valores entre 0,091 y 2,052 μg/mL. COPs totales fueron significativamente superiores (p < 0,05) en pacientes con hipertrigliceridemia, hipertensión, diabetes y sobrepeso/ obesidad con respecto a aquellos sujetos que no presentaron estos factores de riesgo cardiovascular. Además, 7α y 7β-hidroxicolesterol y 7-ketocolesterol mostraron valores mayores (p < 0,05) en pacientes con hipertensión y diabetes. No se observaron diferencias en COPs totales entre pacientes con y sin hipercolesterolemia. Conclusiones: Los resultados de este estudio mostraron que los COPs analizados presentan altos niveles de correlación con, al menos, 4 de 6 factores de riesgo cardiovascular considerados (AU)

Advantage of salivary cortisol measurements in the diagnosis of glucocorticoid related disorders.

OBJECTIVE: Salivary cortisol in the assessment of glucocorticoid related disorders. DESIGN-METHODS: Serum and salivary cortisol were measured in 189 patients (22 Cushing's syndrome, 67 pseudo-Cushing, 11 Addison's disease, 89 controls) at 8:00 and 24:00 h. RESULTS: Serum and salivary cortisol correlated in the whole study population (r=0.62, p=0.000). Morning serum and saliva cortisol in Addison's disease were lower than in controls (6.74+/-1.69 vs 22.58+/-1.78 microg/dL, and 0.15+/-0.25 vs 0.67+/-0.12 microg/dL) (p<0.001). Morning serum cortisol was similar in controls and patients with Cushing's syndrome or pseudo-Cushing (22.58+/-1.78 vs 13.96+/-6.02 vs 16.13+/-1.69 microg/dL). Morning serum and salivary cortisol at 8:00 had the same sensitivity to distinguish patients with Addison's disease from healthy controls. 24:00 am serum cortisol in controls (2.61+/-0.20 microg/dL) was lower than in the pseudo-Cushing group (6.53+/-0.77 microg/dL, p<0.001) and in Cushing's syndrome (10.90+/-2.36 microg/dL, p=0.003). 24:00 am salivary cortisol in controls (0.0025+/-0.001 microg/dL) was lower than in patients with Cushing's syndrome (0.58+/-0.11 microg/dL, p<0.001) and those higher than in patient with pseudo-Cushing (0.10+/-0.06 microg/dL, p=0.001). Both salivary cortisol and serum cortisol presented high specificity (82% and 100%) to detect Cushing's syndrome but salivary cortisol higher sensitivity (saliva 88% and serum 50%). CONCLUSION: Morning salivary cortisol is as good as serum as screening test for patients with Addison's disease and nighttime salivary cortisol is more adequate than serum in the screening of Cushing's syndrome.

Laboratory approach to mitochondrial diseases.

Dysfunction in mitochondrial processes has been related to several pathologies. In these disorders, the cell suffers oxidative imbalance that is mostly due to defects in pyruvate metabolism, mitochondrial fatty acids oxidation, the citric acid cycle or electron transport by the mitochondrial respiratory chain. These metabolic alterations produce mitochondrial diseases that have been related to inherited syndromes, such as MERRF or MELAS. The main affected organs are brain, skeletal muscle, kidney, heart and liver, because of the high energetic demand and the oxidative metabolism. Moreover, the relationship between mitochondrial dysfunction and neurodegenerative processes, such as Parkinson disease or Alzheimer disease, as well as ageing, has been shown. Because mitochondrias are the target of several xenobiotics, such as aspirin, AZT or alcohol consumption, mitochondrial impairment has also been proposed as a mechanism of toxicity. Most laboratory tests that are available in the diagnosis of mitochondrial illness are assayed in tissue biopsies and are usually difficult to interpret. Recently, it has been shown that non-invasive techniques, such as nuclear magnetic resonance or the 2-keto[1-(13)C]isocaproic acid breath test, may be useful to assess mitochondrial function. This article attempts to show the laboratory approach to mitochondrial diseases, reviewing new techniques that could be of great value in the research of mitochondrial function, such as the 2-keto[1-(13)C]isocaproic breath test.

Characterisation with stable isotopes of the presence of a lag phase in the gastric emptying of liquids.

BACKGROUND: Gastric emptying of non-nutrient liquids usually lacks the presence of an initial delay phase (lag phase), and so it has been considered to be monoexponential with an initial rapid phase followed by a slower emptying phase. However a lag phase in the gastric emptying of liquids can be found if there is a high caloric density in the liquid meal. AIM OF THE STUDY: To characterise with stable isotopes the presence of a lag phase in the gastric emptying of non-solid meals. METHODS: Healthy volunteers ingested a low caloric liquid meal (345 KJ/ 200 mL) (LCLM), a high caloric liquid meal (1135 KJ/180 mL) (HCLM) or a semisolid meal (1403 KJ/500 mL) (SSM). Test meals were labelled with 13C-acetate. Breath samples were collected for 13CO2 measurement and data were fitted to a power exponential function. RESULTS: Non-solid meals can have different behaviour related to the initial emptying. The presence of a lag phase in the gastric emptying of liquids was not masked by the processing of the tracer previous to its detection in breath. While the LCLM and SSM showed a rapid initial emptying phase (no lag phase), the HCLM has an initial slow emptying phase. The slower gastric emptying of the HCLM compared to the SSM was related to the presence of a lag phase in the gastric emptying of the HCLM. CONCLUSIONS: The 13C-acetate breath test is very accurate to identify and study the lag phase if present of liquid meals.

[Studying of gastric emptying for solids and liquids by means of using stable isotopes]. / Estudio del vaciamiento gástrico de sólidos y líquidos mediante el empleo de isótopos estables.

The study of gastric emptying is usually performed by scintigraphy. Over the last years alternative non radioactive methods have been developed based on the stable isotopes technology. Such techniques use 13C-octanoic acid to measure gastric emptying of solids and sodium 13C-acetate to measure liquids emptying. The enrichment of 13C in breath air along the time reflects the velocity of gastric emptying. Kinetic parameters can be obtained from this enrichment to quantify gastric emptying. Samples can be obtained outside the processing laboratory. Due to the characteristics of the method, it is adequate and safe to evaluate pathologies related to gastric emptying and the efficiency of the therapy.

[Applications of stable isotopes in biomedical sciences]. / Aplicación de los isótopos estables en ciencias biomédicas.

The employment of stable isotopes technology allows to perform a wide range of studies in vivo avoiding the utilisation of radioactive isotopes. As stable isotopes naturally occur in nature, the technique detects the enrichment in breath air of the tracer administered. Stable isotopes technology is increasingly being used in biomedical investigation due to the security of its use and the development and availability of new substrates. Breath tests such 13C-urea in the detection of Helicobacter pylori and 13C-octanoic acid for gastric emptying are the most important clinical applications.