From the Journals

High recurrence, shortening cycle length in bipolar disorder associated with several biomarkers



Several potential biomarkers may indicate whether patients with bipolar disorder may have high-recurrence disease with a cycle length that progressively shortens, according to Erik Smedler, MD, PhD, of the department of psychiatry and neurochemistry at Gothenburg (Sweden) University.

For the analysis, published in European Neuropsychopharmacology, Dr. Smedler and fellow investigators recruited 3,074 patients from the Swedish Bipolar Collection between 2009 and 2013 who had at least two inpatient episodes separated by at least 8 weeks. A total of 745 patients had serum samples available; assays for 203 different protein biomarkers were performed on those samples.

The investigators clustered patients according to frequency – with low-frequency recurrence defined as a maximum of one inpatient episode per year – and by cycle length – with sensitized patients having progressively shorter periods between inpatient episodes. No difference in biomarkers or clinical features were seen between high- and low-frequency recurrence patients, but sensitized patients were significantly more ill and were more likely to be treated with antidepressants.

In addition, in a specific cohort of patients who were both sensitized and had a high recurrence rate (at least five inpatient episodes), four proteins were expressed at a significantly lower level than that of nonsensitized patients: tumor necrosis factor receptor-2, tumor necrosis factor receptor superfamily member 4, placenta growth factor, and adrenomedullin. Sensitization also was associated with a single nucleotide polymorphism near the calcium channel gene CACNA2D3.

“These results suggest the potential for translational research aimed at preventive actions,” the investigators wrote.

The authors reported that they had no conflicts of interest.

SOURCE: Smedler E et al. Eur Neuropsychopharmacol. 2019 Aug 1. doi: 10.1016/j.euroneuro.2019.07.132.

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