Studies of Complex Biological Systems with Applications to Molecular Medicine: The Need to Integrate Transcriptomic and Proteomic Approaches

Table 1

Summary of the models used and of the major findings obtained by applying microarray technologies to the study of ageing skeletal muscle.

Authors	Experimental model	Number of analyzed genes	Identified affected pathways
Mouse
Lee et al., 1999 [25]	Studied tissue: aged skeletal muscle.	6347	Stress response, energy metabolism.
Rat
Sreekumar et al., 2002 [28]	12-months-old Sprague-Dawley rats. Studied tissue: gastrocnemius muscle.	800	Energy metabolism, signal transduction, stress response, glucose/lipid metabolism, and structural/contractile function.
Altun et al., 2007 [29]	4- and 30-months-old rats.Studied tissue: gastrocnemius muscle.	6240	Redox homeostasis, iron load, regulation of contractile proteins, glycolysis, and oxidative phosphorylation.
Lombardi et al., 2009 [26]	3- and 24-months-old rats.Studied tissue: gastrocnemius muscle.	1176	Energy metabolism, mitochondrial pathways, myofibrillar filaments, and detoxification.
Human
Welle et al., 2003 [23]	21–27 yr of age and 67–75 yr of age.Studied tissue: vastus lateralis muscle.	44 000	Cell cycle/cell growth, inflammation, signal transduction, protein metabolism, transcription, stress response/DNA repair, energy metabolism, and hormonal.
Welle et al., 2004 [19]	20–29 yr of age and 65–71 yr of age, women.Studied tissue: vastus lateralis muscle.	1000	Stress response/DNA repair, energy metabolism.
Zahn et al., 2006 [21]	16 and 89 yr of age. Studied tissue: skeletal muscle.	54 675	Electron transport chain, cell cycle/cell growth, extracellular matrix, chloride transport, complement activation, ribosomes.