Tissue biopsy techniques for gene‐expression profiling in clinical pharmacology

Gene‐expression profiling studies require sufficient quality/quantity mRNA to obtain valid results. In animal studies, obtaining relevant tissue material is not a problem, but in humans there are obvious constraints. Therefore, we evalauted tissue biopsy techniques, perceived burden and the RNA extraction methods in 12 healthy subjects. On a single day a muscle and fat biopsy were done and a 10ml blood sample was taken, followed by follow‐up visits after 3 and 7 days. Abdominal sc adipose tissue was sampled with a suction technique after local anaesthesia. Muscle tissue was sampled with a modified Bergström needle from the quadriceps muscle under sterile conditions and local anaesthesia. Tolerability was assessed with questionnaires directly after the procedure and at follow‐up visits. The procedures were well tolerated by all subjects. The fat biospy was associated with none to minimal discomfort both during the procedure and during follow‐up. The discomfort of the muscle biopsy was rated as comparable to the venepuncture. At follow‐up a mild bruise‐like feeling for a median time of 48 hrs was reported. The average and (range) RNA yield of the leucocytes was 13 (2.3–28.8) μg. On average 237 (79–353) mg muscle tissue was sampled. Half of each sample was analysed for RNA quantity, yielding on average 16.9 (4.1–41.8) μg RNA. From the average 197 (61–430) mg adipose tissue 3.9 (1.4–8.5) μg RNA could be obtained. RNA from all samples was of good quality. Gene‐expression profiling with the material showed significant associations between anthropometric variables and genes involved in glucose homeostasis. Thus, tissue sampling in human is feasible and can be used for gene‐expression profiling clinical pharmacology studies. Clinical Pharmacology & Therapeutics (2004) 75 , P69–P69; doi: 10.1016/j.clpt.2003.11.260