International Journal of Molecular Sciences Article Depression, GABA, and Age Correlate with Plasma Levels of Inflammatory Markers 1, 2, 1 3 2 Amol K. Bhandage y, Janet L. Cunningham y, Zhe Jin , Qiujin Shen , Santiago Bongiovanni , Sergiy V. Korol 1 , Mikaela Syk 2, Masood Kamali-Moghaddam 3, Lisa Ekselius 2 and Bryndis Birnir 1,* 1 Department of Neuroscience, Physiology, Uppsala University, BMC, Box 593, 75124 Uppsala, Sweden;
[email protected] (A.K.B.);
[email protected] (Z.J.);
[email protected] (S.V.K.) 2 Department of Neuroscience, Psychiatry, Uppsala University, 75185 Uppsala, Sweden;
[email protected] (J.L.C.);
[email protected] (S.B.);
[email protected] (M.S.);
[email protected] (L.E.) 3 Department of Immunology, Genetics and Pathology, Science for Life laboratory, Uppsala University, 75108 Uppsala, Sweden;
[email protected] (Q.S.);
[email protected] (M.K.-M.) * Correspondence:
[email protected]; Tel.: +46-18-471-4622 These authors contributed equally to this work. y Received: 22 October 2019; Accepted: 4 December 2019; Published: 6 December 2019 Abstract: Immunomodulation is increasingly being recognised as a part of mental diseases. Here, we examined whether levels of immunological protein markers changed with depression, age, or the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). An analysis of plasma samples from patients with a major depressive episode and control blood donors (CBD) revealed the expression of 67 inflammatory markers. Thirteen of these markers displayed augmented levels in patients compared to CBD. Twenty-one markers correlated with the age of the patients, whereas 10 markers correlated with the age of CBD.