Calibration of non-invasive measurement of mitochondrial oxygenation in healthy volunteers

A new in vivo technique to measure mitochondrial oxygen tension was recently
developed by our lab and at this moment the first trials are performed with the
clinical monitor. A small but significant difference between oxygen tension
levels is observed between the new measurements and the earlier data
(experimental research and data from other devices published elsewhere).
To make sure correct values are shown a two-point calibration should be done
for this device. Using an arterial blood gas sample, an incubator and a short
period of reversible inhibition of mitochondrial function on skin a two-point
calibration could be done in vivo in healthy volunteers.

Calibration of the mitochondrial oxygen tension technique in the human skin

a study in healthy volunteers.

ALA plaster Pp-IX accumulation in the skin. This enables the mitochondrial
oxygen tension measurement.
Mitochondrial respiration inhibition cream to make the oxygen tension the cells
temporary equal to the oxygen tension in the blood.

The intracellular oxygen measurement is a non-invasive measurement technique.
The specific discomfort for the subject is that an aminolevulic acid
containing-plaster is applied that makes the skin sensitive for light. This
plaster is applied on the skin 5-8 hours before the measurement. The
measurement device is called the COMET monitor, able to measure cutaneous
mitoPO2 and mitoVO2 by means of oxygen-dependent quenching of delayed
fluorescence of mitochondrial protoporphyrin IX.
An arterial blood sample is needed for this calibration to determine the oxygen
tension, performed by skilled clinicians. Reversible inhibition of the electron
transporter chain is achieved by topical application of cyanide, in a very low
dose. Toxicity of cyanide differs per entrance way, by topical application on
skin the LD50 is estimated at 100mg/kg bodyweight. {Harper:1997} We intent to
give an aliquot of maximal 1 ml with the concentration 10mg/gr KCN in lanette
crème. The measurement area is 2 cm2, on this area the cyanide cream is
applied. The estimated amount of crème used on the skin is at most 10mg. the
COMET measurement system will measure trough the layer of crème, therefore the
amount of crème should be at most 10mg, because the optical properties of
lanette crème will otherwise block the fluorescent signal from the skin. The
amount of crème used will be measured on a laboratory calibrated precision
scale.

For an average person (70kg) 10mg KCN / 70kg is 0.143mg/kg on the skin, this is
at most 0.0143% of the LD50 for a person 70 kg of weight. In contrast the
concentration of hydrogen cyanide (HCN) in tobacco smoke can be as large as 1.5
mg for a single cigar1, and 0.5 mg in a single cigarette2. No relevant toxicity
is expected when applying 0.0143% of the LD50.

Previous to this study during a live demonstration of the COMET on targeting
mitochondria(2015) in Berlin.
This measurement setup demonstration can also be seen at the website of
Photonics Healthcare bv. www.photonicshealthcare.com

Overall, the study comes with a negligible risk and the burden is low.