With a prevalence of more than 15% in ICU, septic shock today represents a real public health problem and remains the leading cause of mortality in ICU. Undernutrition is characterized by an alteration of the body composition and in particular by a loss of muscle mass. In intensive care, there are indirect elements suggesting a link between loss of muscle mass and prognosis.

Muscle mass results from a balance between the pathway of proteolysis and that of protein synthesis, depending on many factors, not one of the most important are insulin. The protein PTP1B (Protein Tyrosine Phosphatase 1B), by the dephosphorylation of its numerous substrates, constitutes an endogenous regulator of numerous intracellular signaling pathways, including that of insulin. PTP1B could play a role in the protein synthesis abnormalities observed during sepsis leading clinically to impaired body composition including muscle body mass. Therefore, we propose to study the association between PTP1B and loss of muscle mass in patients in sepsis in resuscitation.

The intestinal barrier plays an essential role in protecting against microbial luminal flora and the phenomenon of bacterial translocation. Zonulin is one of the major regulators of tight junctions, important actors in the intestinal barrier function. The increase in plasma zonulin levels, greater than 0.6 ng / mg, is directly correlated with increased intestinal permeability (16). However, elevation of plasma zonulin has never been evaluated in septic resuscitation patients. This is why we propose the evaluation of the association between plasma zonulin and the loss of muscle mass in these resuscitation patients.

Inclusion Criteria:

• Septic shock or severe sepsis
• Age > 18 years old
• Affiliation to a social security system
• Information and consent. If patient cannot give his consent, an emergency consent will be sign by trusted person
• Contraception for woman, of childbearing age

Exclusion Criteria:

• Pregnancy or breastfeeding
• Prisoners
• Patient with pacemaker or defibrillator
• patient participating to a clinical trial with the same primary outcome