Abstract
CSF sampling from both the lumbar and cisterna magna location of cynomolgus monkeys, is frequently required during the conduct of regulatory studies for assessment of inflammatory cerebral conditions. With only limited reference data available in the literature, a laboratory based background data set is considered important. CSF samples, taken by lumbar or cisterna magna puncture, from overall 73 (19 male and 54 female) cynomolgus monkeys were used to determine hematology parameters including immunophenotyping of lymphocyte subsets in low volume (0.4 – 1.0 mL) of CSF. Additionally, analysis was conducted in EDTA blood as reference. Results showed that it is critical to avoid sampling related CSF contamination with peripheral blood. The risk of contamination was higher for sampling from the cisterna magna. The samples with low red blood cell numbers were investigated separately. Alternatively, a cisterna magna port catheter system can be surgically implanted to allow repetitive CSF collection on non sedated animals, without blood contamination. Lymphocytes represented the predominant cell population (a mean of approximately 90% for both sampling methods). Within the lymphocytes, T cells were almost exclusively present (mean >97%) with T Helper cells being the largest population (means of 59.7% and 57.8% for lumbar and cisterna magna sampling).
In conclusion, these data are considered helpful for the assessment of inflammatory cerebral conditions in non-human primate toxicity studies. Lumbar puncture allows for repeated dosing and comparison of predose and dosing phase data.
