Title: Neuropathic pain treatment: Gene transfer to nociceptive neurons
Duration: 01.3.2011. - 01.5.2011.
Project leader: Sandra Kostic, M.Sc. (Laboratory for Pain Research)
Project co-applicant: Professor Damir Sapunar, M.D., Ph.D. (Laboratory for Pain Research)
Collaborators: Professor Quinn Hogan, M.D. (Department of Anesthesiology, MCW, USA)
Funding: Unity Through Knowledge Fund 2A
Administering institution: School of Medicine, University of Split, Croatia
Summary: Neuropathic pain is a maladaptive, persistent pain syndrome that results from damage to the peripheral or central nervous system (CNS). Its pathogenesis is incompletely understood and treatments are often inadequate. Exploration of the mechanisms producing neuropathic pain has been aided by the interventions targeted to dorsal root ganglion (DRG) which is the primary site of initial pathological changes that lead to neuropathy. A strong impetus for developing a suitable model of DRG injection is the avoidance of systemic and CNS toxicity during neuropathic pain treatment. However, targeted DRG delivery in small animal subjects is a methodological challenge, as DRGs are enclosed within the intervertebral foramen and are therefore not easily accessible for injection. We propose a short two-month visit to the established scientific group with an extensive experience in gene delivery to nociceptive neurons. Our goal is to adopt gene transfer technology targeted to DRGs, and with the help of this methodology strengthen previous and gain new collaborations, increase our research and innovation capacities and attract international funding. Acquiring this technique will additionally enable education of young scientists in our PhD programs.
Project results
The main objective of this visit was to learn and transfer to our laboratory technology of DRG targeted gene transfer.
The first part of the visit included learning surgical methodology. Direct injection of drugs into the dorsal root ganglion in small experimental animals represents a methodological challenge. The ganglion is situated in intervertebral foramen so it is not easily accessible. The surgical approach included the method of selective DRG injection - microsurgical approach using a minimal foraminotomy, orientation and selection of appropriate DRG, injection using a motorized injection system through a pulled glass micropipette. This approach optimizes efficacy of injected drug or a compound. It limits influences on other neuronal population, which is important for avoidance of serious side effects that inevitably accompany systemic medication.
For the first two weeks, I was observing experts doing this surgery and I was getting familiar with the equipment. After finishing the course and obtaining the license to work with experimental animals, I started to perform surgery on my own.
During the second part of the visit I was learning a new therapeutic approach for neuropathic pain, gene transfer technology. I was observing the manipulation with viral vectors and its delivery to DRG. This included the evaluation of injectate distribution - spreading of the solution with dye injectate to quantify the necessary amount and later spreading of the viral components. The virus used in this research for gene therapy was adeno-associated virus. It is one of the most promising viral vectors for human gene therapy. It did not contain any specific therapeutic gene. The viral vector in this case carried a gene that coded for a marker, green fluorescent protein (GFP). This helped us to evaluate the efficacy of viral transduction inside the targeted dorsal root ganglion using immunohistochemical methods.
After my return, during May, we established functional system for targeted delivery of drugs into DRG. Due to additional financing, we were able to purchase all the necessary equipment for the drug delivery system. This helped us to accomplish this activity much faster than it was planned.
The setup for direct DRG injection at
Laboratory for Pain Research in Split
The PhD program Translational Research in Biomedicine – TRIBE started during May 2011. This methodology is included in the program of one obligatory and one elective course.
Public outreach was achieved through interview for University newspaper "Universitas No. 19" (published as a supplement of Slobodna Dalmacija) about UKF 2A grant and my results.
Professor Quinn Hogan and his team
from Laboratory for Pain Research, MCW
povratak na Laboratorij za istraživanje boli
back to Pain Research Group
