The United States has experienced an opioid crisis over the past 25 years. According to the U.S. CDC, nearly 841,000 people have died from drug overdoses between 1999 and March 2021. The sad background is that most of the victims had previously been prescribed painkillers by their doctors. Starting in 1996, the prescription painkiller Oxycontin was given, which the Sackler family and their company Purdue Pharma introduced to the North American market and aggressively promoted as painkilling with a supposedly very low potential for addiction. However, after the prescription period expired, patients addicted to it could no longer afford these expensive drugs and switched first to heroin, then to the less expensive and highly potent synthetic fentanyl. To date, research into issues surrounding addiction has taken place in animal models, which are known to have limited applicability to humans.

The pre-Bötzinger complex is considered the pacemaker of the respiratory center. It is part of the ventral respiratory group of neurons in the ventral area of the medulla oblongata, the brain stem located between the pons and spinal cord. The pre-Bötzinger complex coordinates the inspiratory and exspiratory groups of neurons by alternating rhythmic excitation or inhibition. In the event of an opioid overdose, this complex is the first to shut down, leading to death by suffocation in the patient.

The researchers from Orlando succeeded in developing a differentiation protocol for their model with which these neurons could be successfully developed from induced pluripotent stem cells for the first time. Immunocytochemical methods demonstrated that the neurons thus generated expressed essential pre-Bötzinger complex markers. Electrophysiological responses to pre-Bötzinger complex modulators were analyzed using patch-clamp electrophysiology.

With their model, the scientists were able to simulate far more accurately the dose-dependent inhibition of the activity of these neurons for four different opioids with IC50 values. Efficacy by the opioid antagonist naloxone used in emergency medicine in a concentration-dependent manner was also demonstrated.

The researchers are currently establishing a human-on-a-chip with five organ replicas, including the pre-Bötzinger complex neurons, liver, heart, kidney, and skeletal muscle tissue, to monitor not only the effects of overdose, but also organ-specific functional changes in each opiate-induced overdose and rescue, among others.

The Hesperos team believes their extraordinary model paves a way for new, more effective treatments.

Original publication:
Guo X, Akanda N, Fiorino G, Nimbalkar S, Long CJ, Colón A, Patel A, Tighe PJ, Hickman JJ. Human IPSC-Derived PreBötC-Like Neurons and Development of an Opiate Overdose and Recovery Model. Adv Biol (Weinh). 2023 Sep 7:e2300276. doi: 10.1002/adbi.202300276. Epub ahead of print. PMID: 37675827.

More information:
https://hesperosinc.com/first-overdose-model-published-in-advanced-biology/
https://www.businesswire.com/news/home/20230907562670/en/New-Study-Describes-First-Functional-Human-Model-to-Investigate-Opiate-Overdose-and-Recovery