Recommendations for Future Research
The participants suggested that to begin with, NIDA should support the following research activities: (i) Establish a network of forensic pathologists at at least three regional sites for tissue collection, e.g., Florida and Maryland for studying cocaine, opiates, and MDMA-related issues; and California for studying methamphetamine, opiates, and MDMA; (ii) Establish a central holding site with three or four collection sites; (iii) After taking into consideration various state laws, obtain cooperation from physicians who will inform the investigators the availability of the brain tissue as soon as possible; (iv) Develop training manuals; train appropriate staff and develop common protocols for tissue handling; train local staff, nurse or social workers to make the necessary telephone calls and to conduct retrospective evaluations with family members and next-of-kin, and perform consensus review by psychiatrists and forensic pathologists; (v) Develop a procedure such that brains will be sent to one regional storage site for distribution; assign bar codes for all samples; train technicians for brain tissue dissection; and finally (vi) Store separately the brain and hair specimens for toxicology (e.g., cerebellar specimens taken for allele expression, SNPs, etc.). Individualized handling can be accomplished to meet NIDA-funded study protocols (i.e., immunostaing, etc).
- Critical elements for the successful use of postmortem tissue and brain bank resources.
- Develop a genuine, symbiotic and collaborative working relationship between investigators and the Medical Examiner.
- Encourage the standardization of tissue harvesting, handling, preparation, and preservation across as many ME offices and Brain Banks as possible.
- Standardize methods for compiling antemortem clinical data, disease and drug taking histories, and toxicology reports.
- Develop networks, collaborations, and communications for the maximal use of available tissue. Use sufficiently large sample sizes with appropriately matched subjects (age, gender, history, etc).
- Use anatomical verification of microarray, Northern blotting, Western blotting and other primary levels of analysis in intact (frozen or fixed) tissue as a secondary or tertiary level of analysis.
- Psychiatric, neurological, and drug abuse disorders can be studied at molecular and anatomical levels. HIV-induced neurotoxicity and other comorbid conditions often accompanying all of these disorders can also be studied effectively and can yield interpretable results.
- Viable tissue models can emerge from properly preserved PM tissue and these models can be used to study other than end-stage disease states. For example, HIV infection of cultured cells or slices from PM tissue shows morphological changes that are seen in intact tissue from individuals with HIV. Studies of disease mechanisms, their progression, and protective measures can also be studied.
- PM tissue studies targeting specific structures, neural systems, proteins and genes for study.
- Support the use of newer techniques that are being currently used such as: quantitative RT-PCR, in situ hybridization, immunocytochemistry, laser-capture microscopy, and functional studies of enzymes and transporters. Expansion to studies of the genome, the transcriptome, and the proteome are feasible and are entering productive stages through the use of microarray, massively parallel signature sequencing (MPSS), and mass spectrometry technologies. The emerging technologies such as microarray, high-resolution structural studies of the nervous system, MPSS, and mass spectrometry can now detect low copy number transcripts that were previously below the level of detection.
- PM tissue can be used to develop biomarker profiles that can be linked to specific diseases. This can have important feedback to the ME as part of the autopsy report and can advance the study of diseases of the central nervous system in humans.
- Results are dispelling the image that PM tissue degrades too rapidly to allow its use in experimentation. In fact, postmortem interval and brain pH, within reasonable limits, do not influence the integrity of mRNA, as one example. While overall yields may decrease under non-ideal conditions, the quality and integrity of harvested mRNA remains high.
- Use of PM tissue for structural and functional studies of the brain meshes very well with neuroimaging results.
- Recommendation for NIH to implement:
- NIH should take a proactive stance in advocating the use of autopsy material for research in diseases of the central nervous system.
- NIH should "educate" CSR Study Sections to help them appreciate the scientific validity and importance of grant applications using PM tissue. Use of PM tissue is often characterized by study sections as descriptive, or lacking a hypothesis-driven approach. This characterization is often at odds with the publication of data from PM studies in journals with the highest scientific impact.
- NIH should establish a Special Emphasis Panel to review highly specialized grant applications that focus on the use of PM tissue.
- NIH should earmark stabilized funding mechanisms for studies of PM tissue. This could include, but is not limited to, RFAs, cutting-edge/high-risk studies, or other multi-center networks. These mechanisms should support banking infrastructures at a minimum to help defray the high expense of obtaining and preserving the highest quality tissue possible.
- Brain banks and tissue repositories should be networked through a common database so that investigators could query the database for tissue availability, request tissue, share pathological workups, and share data where appropriate.
- Additional studies should be encouraged to establish optimal conditions for tissue preparation and preservation to include the "unfixing" of already-fixed tissues. Certain repositories have very large numbers of fixed tissues, but their use with some experimental approaches is currently restricted by fixation.
- NIH should encourage establishment of effective collaborations/sharing of scarce control cases through effective brain bank networking.
- NIH should encourage international collaborations that allows comparison of very different patient cohorts. Barriers to international collaboration in brain banking may be more perceived than real since mutually acceptable consent procedures and ethical approval for brain banking may already be in place.
- Finally, postmortem human brain tissue should prove increasingly valuable for any brain related institute in efforts to elucidate normal brain development and/or disease related pathophysiology. This should be of value to the NINDS, NIMH, NIDA, NIAAA, NIA, NICHD, NEI and NIDCD and their intramural research programs.