Table 1.

Measures of Mitochondrial Function

Mitochondrial Measurements	Examples	Description
Mitochondrial structure
	1) Histology	Measurement of mitochondrial size and morphology on electron microscopy
	2) mt DNA copy number	Measurement of mitochondrial DNA content
	3)cardiolipin	Measurement of mitochondrial inner membrane area
Markers of Mitochondrial function
Fatty acid oxidation
	1) Carnitine palmitoyltransferase I	Enzyme located in outer mitochondrial membrane and facilitates transport of long chain fatty acids across the membrane
	2) beta-hydroxyacyl dehydrogenase	Enzyme involved in formation of acetyl coA from fatty acid oxidation
	3) fatty acid translocase	Long chain transporter of fatty acids found in plasma and mitochondrial membranes
Oxidative phosphorylation
	1) pyruvate dehydrogenase	Enzyme involved in the conversion of pyruvate to Acetyl CoA
	2) citrate synthase	Enzyme in the 1st step of the TCA cycle (encoded from nuclear DNA)
	3) succinate dehydrogenase	Enzyme in TCA cycle and ETC (complex 2 - encoded from nuclear DNA)
	4) NADH dehydrogenase	Enzyme in electron transport chain (complex 1 - encoded from nuclear and mitochondrial DNA)
	5) cytochrome c oxidase	Enzyme in electron transport chain (complex 4-encoded from nuclear and mitochondrial DNA)
Uncoupling proteins
	UCP1-3	Dissipates proton gradient across inner mitochondrial membrane to separate electron transport from oxidative phosphorylation
Measures of mitochondrial function
	1) O2 consumption	Measurement of O2 consumption under various scenarios of substate/ ADP/ ATP inhibitor availability
	2) fatty acid oxidation
	a) lipid utilization	Extraction of mitochondrial and measurement of mitochondrial CO2 production after exposure to lipid
	b) fatty acid transport	Extraction of mitochondria and measurement of lipid uptake
	3) In vitro ATP production	Extraction of mitochondria and measurement of ATP production with various substrates
	4) In vivo ATP production	Magnetic resonance spectroscopy based measurement of TCA cycle rate using 13C
		Magnetic resonance spectroscopy based measurement of ATP synthesis or phosphocreatinine resynthesis using 31P
Mitochondrial biogenesis markers
	1) Peroxisome proliferator- activated receptor gamma coactivator-1 alpha (PGC-1a)	Master regulator of mitochondrial function
	2) AMP-activated protein kinase (AMPK)	Enhances oxidative (instead of glycolytic) energy production, objects of activation include PGC-1a and TFAM
	3) Mitochondrial transcription factor A (TFAM)	Activator of mitochondrial transcription and mitochondrial genome replication