Sphingo-lipotoxicity and Trans-differentiation of Adipose Tissue in Obesity (SFINGOTRANS)
Condition: Obesity; Healthy
MeSH terms: Obesity
Study type: Observational

Summary: 
      After recruiting a population of subjects with different metabolic severity (subjects of
      normal weight and obese patients with and without metabolic syndrome), the objectives of the
      present research will be:

        1. determine leukocyte mRNA levels of Cidea (gene associated with BAT functional status),
           Hoxc9 (gene associated with browning of WAT) and Cpt1a (gene associated with β-oxidation
           of fatty acids in both tissues, i.e. BAT and WAT) (secondary endpoint);

        2. to determine energy expenditure with indirect calorimetric technique, body temperature
           and circulating catecholamine levels, which will be correlated to leukocyte levels of
           Cidea, Hoxc9 and Cpt1a mRNA (secondary endpoint);

        3. determine the plasma levels of an extensive panel of sphingolipids, including in
           particular ceramides and sphingosine-1-phosphate which, by exerting a lipotoxic,
           lipoinflammatory and anti-adipogenic effect, will be correlated to the leukocyte levels
           of Cidea, Hoxc9 mRNA and Cpt1a (primary endpoint);

        4. determine the erythrocyte, leukocyte and platelet levels of sphingolipids which, acting
           as peripheral biomarkers of cardiometabolic dysfunction (e.g., atherogenesis,
           thromboembolism, arterial hypertension, insulin resistance, low-grade chronic
           inflammation, etc.), could phenotypically identify patients with increased
           cardiovascular risk (e.g., obese patients with or without metabolic syndrome) (secondary
           endpoint).

      Hypothesis: the existence of a relationship between sphingohypotoxicity and
      transdifferentiation of adipose tissue and a combination of sphingolipids
      (plasma/erythrocyte/platelet/leukocyte) and gene regulators (WAT/BAT-related) which, with
      sensitivity and specificity, is associated with diagnosis of metabolic syndrome.
    

Detailed description: 
      Materials and methods Patients: 90 adults of both sexes will be recruited, of whom 30 of
      normal weight (age: 18-50 years; BMI < 25 kg/m2), 30 obese without metabolic syndrome (age:
      18-35 years; BMI > 35 kg/m2) and 30 obese with metabolic syndrome (age: 18-35 years; BMI > 35
      kg/m2), according to the 2009 IDF criteria. Subjects of normal weight will be recruited from
      medical/paramedical staff, while obese patients from hospitalized at the Division of
      Metabolic Diseases, Istituto Auxologico Italiano, Piancavallo (VB), Italy, for a 3-week
      multidisciplinary weight reduction program (BWRP), which includes low-calorie diet, physical
      exercise, psychological support and nutrition education.

      Subjects with other pathologies other than obesity will be excluded from the study, including
      those treated with anticoagulant and antiplatelet drugs, since the evaluation of
      intraplatelet levels of sphingolipids will be foreseen.

      In basal conditions, the main anthropometric data will be collected (weight, height, waist
      circumference, hip circumference, BMI), body composition will be evaluated with a
      bioimpedance technique, the main cardiovascular parameters will be recorded (blood pressure
      and heart rate), a calorimetric examination will be performed, collection of body temperature
      (morning and evening), request of the environmental temperature to which one is generally
      exposed during the day and determined, with automated clinical biochemistry techniques, the
      following biochemical parameters: glucose, total cholesterol, triglycerides, LDL, HDL, fatty
      acids non-esterified, insulin, glycated Hb, catecholamines and C-reactive protein.

      Determination of the lipidomic profile in plasma and cell extracts A lipidomics will be
      performed in plasma and in cellular extracts from erythrocytes, leukocytes and platelets. The
      levels of the individual analytes will be determined with a technologically advanced
      analytical instrumentation, consisting of a triple quadruple hybrid mass spectrometer with
      linear ion trap (QTRAP 5500, AB Sciex), interfaced with an ultra-high performance liquid
      chromatograph (UHPLC).

      Plasma and cellular levels of the following sphingolipids will be measured: ceramides and
      dihydroceramides from C16 to C24, including 2 unsaturated ones (C18:1 and C24:1), the
      sphingomyelins (those from C16 to C24 and the one C24:1), sphingosine, sphinganine ,
      sphingosine-1-phosphate and sphinganine-1-phosphate.

      Determination of leukocyte mRNA levels of gene regulators From an aliquot containing
      leukocytes, stored ad hoc, the total mRNA will be extracted and, with RT/PCR technique, the
      leukocyte mRNA levels of the following genes will be determined: Cidea, Hoxc9 and Cpt1a.
    

Intervention name(s): Blood sample collection
Intervention type(s): Diagnostic Test
Intervention description(s): Blood sample collection
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Obese patients (BMI > 35 kg/m2) and age- and sex-matched healthy controls (normal weighted)
      
Biospecimen description: 
      Plasma and serum samples
    
Keywords: Obesity; Normals; Adipose tissue; Sphyngolipids; Metabolic syndrome