MedWire News: Overweight patients with bipolar disorder exhibit higher levels of certain adipokines and inflammatory markers than overweight mentally healthy individuals, research shows.
"Adipokines are adipocyte-derived secretory factors which have functions in immune response and seem to be associated with both bipolar disorder and overweight," explain Antonio Lucio Teixeira (Universidade Federal de Minas Gerais, Belo Horizonte, Brazil) and team.
However, they add: "Despite the vast literature showing the role of adipokines in obesity, their role in bipolar disorder is still undetermined. Their relation with other inflammatory parameters is also under investigated in bipolar disorder."
To investigate further, the researchers studied 30 overweight (mean body mass index [BMI] 29.14 kg/m2) euthymic bipolar I disorder patients and 30 overweight (mean BMI 28.26 kg/m2) age-, gender, and BMI-matched mentally healthy individuals (controls).
Blood samples were collected from all of the participants and assessed for plasma levels of the adipokines adiponectin, resistin, and leptin, and for levels of the inflammatory marker tumor necrosis factor (TNF)-α and its soluble receptors sTNFR1 and sTNFR2 using enzyme-linked immunosorbent assay.
Patients with bipolar disorder were also assessed for clinical parameters using the Mini-International Neuropsychiatric Interview, the Young Mania Rating Scale (YMRS), and the Hamilton Depression Rating Scale (HDRS).
Analysis revealed that bipolar disorder patients had significantly higher mean plasma levels of adiponectin and leptin compared with controls, at 37,013 versus 8282 pg/mL, and 2130 versus 1485 pg/mL, respectively.
Furthermore, bipolar disorder patients had significantly higher mean plasma levels of sTNFR1 than controls, at 1288 versus 666 pg/mL.
There was no significant difference between bipolar disorder patients and controls regarding plasma levels of resistin, TNF-α, and sTNFR2.
Plasma levels of adipokines, TNF-α, and its soluble receptors did not differ among bipolar disorder patients according to the presence of psychiatric comorbidities, medical comorbidities, or medication use.
In addition, plasma levels of adipokines were not correlated with age, length of illness, BMI, YMRS scores, or HDRS scores, or with plasma levels of TNF-a, sTNFR1, or sTNFR2.
Teixeira and team conclude: "Our results corroborate the view that inflammatory mechanisms, including adipokines, may contribute to bipolar disorder.
"The changes in these peripheral markers in bipolar disorder reinforce the idea of a systemic illness and a different profile in inflammatory mechanisms linked with obesity."
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