Study of the activity of BAT in patients with phenylketonuria

Noemí López, Adela Urisarri Ruiz De Cortázar, Maria Luz Couce Pico, Miguel Antonio López Pérez

Keywords: Brown adipose tissue, catecholamines, FGF21, phenylketonuria, obesity

Background:

Thermogenesis is the set of metabolic reactions whose final objective is the genesis of heat to maintain body temperature, this process takes place in brown adipose tissue. Patients with phenylketonuria have a deficiency in the activity of the enzyme phenylalanine hydroxylase, which leads to a decrease in the concentration of tyrosine, an essential amino acid for the synthesis of catecholamines, with the consequent affectation of the adrenergic pathway that regulates brown adipose tissue.

Research questions:

How is termorregulation in patients with PKU and M-HPA
Is there any correlation between body temperature,BAT temperature and metabolic, hormonal and anthropometric meassures in the different groups?

Method:

We have studied the activity of adipose tissue in patients with phenylketonuria, moderate hyperphenylalaninemia and healthy controls using infrared video thermography. In addition, possible correlations between body temperature and
brown adipose tissue with metabolic, hormonal, anthropometric and dietary parameters in the different groups were investigated.

Results:

The results obtained showed a positive correlation between the brown adipose tissue temperature gradient and peripheral body temperature in all three groups, although the body temperature in the group of patients with phenylketonuria was maintained at the expense of a higher brown adipose tissue temperature. These patients also presented higher levels of triglycerides, one of the main substrates of brown adipose tissue, as well as a positive correlation with its activity. In this group, higher levels of FGF21 were also observed, as well as different ratios in the concentrations of catecholamines with respect to tyrosine, an essential amino acid in its synthesis, which could indicate some limiting reaction in the conversion of adrenaline leading to greater stimulation of BAT.

Conclusions:

Patients with PKU show higher body temperature and higher BAT temperature.
Patients with PKU show higher concentrations of tryglicerides with possitive correlation with the temperature of BAT
Patients with PKU show higher levels of FGF21

Points for discussion:

Is it possible to start research in basic science in primary care?

How can primary care contribute to basic science research?

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