Fine needle aspiration coupled with real-timePCR: A painless methodology to study adaptivefunctional changes in skeletal muscle

Background and aim: In this study we developed a new methodology for obtaining human skeletal muscle samples to evaluate gene expression. This approach is based on a fine needle aspiration technique, which allows us to extract a small tissue sample in a significantly less invasive manner than with classic biopsy. Methods and Results: Multiplex tandem RT-PCR was used to determine the mRNA levels of genes involved in ATP production and mitochondrial biogenesis in muscle tissue. Samples of vastus lateralis muscle were obtained from 21 healthy subjects with different fitness levels. The principal findings in our study show a strong correlation between PGC-1alpha and COX5B (p<0.001) and between PGC-1alpha and MT-CO2 (p=0.017) expression. Furthermore, a significant positive correlation between mtDNA content and the percentage of MHCI present in the aspired samples were found (p=0.028). These data are in agreement with current knowledge on skeletal muscle physiology and show the reliability of the proposed method. Conclusion: This painless methodology can be used to investigate, in vivo, human muscle RNA and DNA adaptations in response to either physiological and/or pharmacological stimuli. This method has major clinical relevance, such as its application in clarifying the mechanisms underling metabolic and systemic disorders.