Insulin-Like Hormone Increases Lithium Sensitivity in Bipolar Patients

Rapidly swinging from extremes of joy and energy to sadness, fatigue, and confusion, bipolar disorder (BD) patients feel desperate and largely alone in the world. And according to the National Institutes of Health, between 25-50 percent of the roughly 3% of Americans living with BD attempt suicide at least once. Lithium is among the most effective therapies for BD, and remains the first-line treatment even as other mood stabilizing drugs have become available. But about half of the patients prescribed lithium do not respond to the treatment.

A new Tel Aviv University study, published in the Journal of Molecular Neuroscience, may pave the way for improving the efficacy of lithium in these patients. The study found that the insulin-like growth factor 1 (IGF-1) hormone, known for its pivotal role in tissue growth, is also capable of increasing the lithium sensitivity of blood cells in bipolar disorder patients in whom lithium was originally ineffective.

The research was led by TAU postgraduate student Dr. Elena Milanesi under the guidance of Dr. David Gurwitz of the Department of Human Molecular Genetics and Biochemistry of TAU’s Sackler Faculty of Medicine and Sagol School of Neuroscience and Dr. Noam Shomron of the Department of Cell and Developmental Biology at TAU’s Sackler Faculty of Medicine, in collaboration with Sackler graduate student Adva Hadar and Prof. Haim Werner of TAU’s Sackler Faculty of Medicine, along with researchers in Italy and Germany.

A new hope

“Lithium has been considered the cornerstone in the management of bipolar disorder for over 50 years, even though half of patients do not sufficiently respond to chronic lithium treatment,” said Dr. Gurwitz. “It is often prescribed as the first-line treatment for bipolar disorder. If it works, patients take it for years. If not, they have to explore alternatives which haven’t proven as effective in long-term clinical studies.”

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Researchers found that when IGF-1 was added to the cultured blood cells there was increased lithium sensitivity only in the blood cells of those bipolar disorder patients who did not respond to lithium therapy. This image is for illustrative purposes only.

The researchers examined the in vitro effects of insulin-like growth factor 1 (IGF-1) on lithium sensitivity in blood cell lines of both lithium-responsive and non-responsive bipolar patients. They found that when IGF-1 was added to the cultured blood cells there was increased lithium sensitivity only in the blood cells of those bipolar disorder patients who did not respond to lithium therapy.

“Our study suggests that the lack of sufficient IGF-1 activity may underlie lithium resistance in the treatment of bipolar disorder, and this hormone, or drugs mimicking or promoting its action, should be considered for improved treatment of this disorder”, says Dr. Milanesi.

“There are no established animal models for bipolar disorder, so it will be hard to test this idea in animals,” Dr. Gurwitz added. “However, given that IGF-1 is approved for human use in people who are deficient in this hormone, a clinical trial of IGF-1 in lithium-resistant bipolar disorder patients is warranted.”

About this psychology research

Funding: The research on lithium resistance biomarkers was supported by the U.S.-Israel Binational Science Foundation (BSF).

Source: George Hunka – AFTAU
Image Source: The image is in the public domain
Original Research: Abstract for “Insulin-like Growth Factor 1 Differentially Affects Lithium Sensitivity of Lymphoblastoid Cell Lines from Lithium Responder and Non-responder Bipolar Disorder Patients” by Elena Milanesi, Adva Hadar, Elisabetta Maffioletti, Haim Werner, Noam Shomron, Massimo Gennarelli, Thomas G. Schulze, Marta Costa, Maria Del Zompo, Alessio Squassina, and David Gurwitz in Journal of Molecular Neuroscience. Published online March 5 2015 doi:10.1007/s12031-015-0523-8


Abstract

Insulin-like Growth Factor 1 Differentially Affects Lithium Sensitivity of Lymphoblastoid Cell Lines from Lithium Responder and Non-responder Bipolar Disorder Patients

Bipolar disorder (BD) is a chronic psychiatric illness with an unknown etiology. Lithium is considered the cornerstone in the management of BD, though about 50–60 % of patients do not respond sufficiently to chronic treatment. Insulin-like growth factor 1 (IGF1) has been identified as a candidate gene for BD susceptibility, and its low expression has been suggested as a putative biomarker for lithium unresponsiveness. In this study, we examined the in vitro effects of insulin-like growth factor 1 (IGF-1) on lithium sensitivity in lymphoblastoid cell lines (LCLs) from lithium responder (R) and non-responder (NR) bipolar patients. Moreover, we evaluated levels of microRNA let-7c, a small RNA predicted to target IGF1. We found that exogenous IGF-1 added to serum-free media increased lithium sensitivity selectively in LCLs from NR BD patients. However, no significant differences were observed when comparing let-7c expression in LCLs from R vs. NR BD patients. Our data support a key role for IGF-1 in lithium resistance/response in the treatment of bipolar disorder.

“Insulin-like Growth Factor 1 Differentially Affects Lithium Sensitivity of Lymphoblastoid Cell Lines from Lithium Responder and Non-responder Bipolar Disorder Patients” by Elena Milanesi, Adva Hadar, Elisabetta Maffioletti, Haim Werner, Noam Shomron, Massimo Gennarelli, Thomas G. Schulze, Marta Costa, Maria Del Zompo, Alessio Squassina, and David Gurwitz in Journal of Molecular Neuroscience. Published online March 5 2015 doi:10.1007/s12031-015-0523-8

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