Fetal Grafting for Parkinson's Disease: Expression of Immune Markers in Two Patients with Functional Fetal Nigral Implants

In a number of centers throughout the world, fetal nigral transplantation is being performed for the treatment of Parkinson's disease (PD). Clinical results have been inconsistent. One parameter that differs among transplant studies is the degree and manner by which patients are immunosuppressed following transplantation. Indeed, the role of the immune system following fetal grafting in humans is not well understood. Recently, two patients from our open label trial that received fetal nigral implants have come to autopsy. These patients were immunosuppressed with cyclosporin for 6 mo posttransplantation and survived for a total of 18 mo postgrafting. Robust survival of grafted dopamine-containing cells was observed in both cases. Immunostaining for HLA-DR revealed a dense collection of cells within grafts from both cases. HLA-DR staining was rarely observed within the host including non-grafted regions of the striatum. A more detailed analysis of immune markers was performed in Case 2. Numerous pan macrophages, T-cells, and B-cells were observed within graft sites located in the postcommissural putamen. In contrast, staining for these immune cells was not observed within the ungrafted anterior putamen. These findings suggest that even in healthy appearing functional nigral implants, grafts are invaded by host immune cells that could compromise their long-term viability and function. Alternatively, immune cells are known to secrete trophic factors, which may ultimately favor graft survival and function. Further work is needed to understand the role of the immune system in fetal grafting.

Visualization of fibrillar amyloid deposits in living, transgenic Caenorhabditis elegans animals using the sensitive amyloid dye, X-34

Transgenic Caenorhabditis elegans animals can be engineered to express high levels of the human beta amyloid peptide (Abeta). Histochemistry of fixed tissue from these animals reveals deposits reactive with the amyloid-specific dyes Congo Red and thioflavin S (Fay et al., J. Neurochem 71:1616, 1998). Here we show by immuno-electron microscopy that these animals contain intracellular immunoreactive deposits with classic amyloid fibrillar ultrastructure. These deposits can be visualized in living animals using the newly developed, intensively fluorescent, amyloid-specific dye X-34. This in vivo staining allows monitoring of amyloid deposition in individual animals over time. The specificity of this staining is demonstrated by examining transgenic animals expressing high levels of a non-fibrillar beta peptide variant, the beta single-chain dimer. These animals have deposits immunoreactive with anti-beta antibodies, but do not have X-34 deposits or deposits with a fibrillar ultrastructure. X-34 can also be used in vivo to visualize putative amyloid deposits resulting from accumulation of human transthyretin, another amyloidic protein. In vivo amyloid staining with X-34 may be a useful tool for monitoring anti-amyloidic treatments in real time or screening for genetic alterations that affect amyloid formation.

Human casein kinase Idelta phosphorylation of human circadian clock proteins period 1 and 2

Casein kinase Iepsilon (CKIepsilon), a central component of the circadian clock, interacts with and phosphorylates human period protein 1 (hPER1) [Keesler, G.A. et al. (2000) NeuroReport 5, 951-955]. A mutation in CKIepsilon causes a shortened circadian period in Syrian Golden hamster. We have now extended our previous studies to show that human casein kinase Idelta (hCKIdelta), the closest homologue to hCKIepsilon, associates with and phosphorylates hPER1 and causes protein instability. Furthermore, we observed that both hCKIdelta and hCKIepsilon phosphorylated and caused protein instability of human period 2 protein (hPER2). Immunohistochemical staining of rat brains demonstrates that CKIdelta protein is localized in the suprachiasmatic nuclei, the central location of the master clock. These results indicate that CKIdelta may play a role similar to CKIepsilon, suggesting that it may also be involved in regulating circadian rhythmicity by post-translation modification of mammalian clock proteins hPER1 and 2.

Fetal grafting for Parkinson's disease: expression of immune markers in two patients with functional fetal nigral implants

In a number of centers throughout the world, fetal nigral transplantation is being performed for the treatment of Parkinson's disease (PD). Clinical results have been inconsistent. One parameter that differs among transplant studies is the degree and manner by which patients are immunosuppressed following transplantation. Indeed, the role of the immune system following fetal grafting in humans is not well understood. Recently, two patients from our open label trial that received fetal nigral implants have come to autopsy. These patients were immunosuppressed with cyclosporin for 6 mo posttransplantation and survived for a total of 18 mo postgrafting. Robust survival of grafted dopamine-containing cells was observed in both cases. Immunostaining for HLA-DR revealed a dense collection of cells within grafts from both cases. HLA-DR staining was rarely observed within the host including nongrafted regions of the striatum. A more detailed analysis of immune markers was performed in Case 2. Numerous pan macrophages, T-cells, and B-cells were observed within graft sites located in the postcommissural putamen. In contrast, staining for these immune cells was not observed within the ungrafted anterior putamen. These findings suggest that even in healthy appearing functional nigral implants, grafts are invaded by host immune cells that could compromise their long-term viability and function. Alternatively, immune cells are known to secrete trophic factors, which may ultimately favor graft survival and function. Further work is needed to understand the role of the immune system in fetal grafting.