Measure intracellular oxygen availability in humans during photodynamic therapy
ID
Source
Brief title
Condition
- Cornification and dystrophic skin disorders
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Intracellular oxygen availability
Secondary outcome
• Skin temperature at the lesion
• Sensor temperature
• Accuracy of cellular oxygen measurement (variation of repeated measurements
with
stable circumstances)
• Minimum measured value, expected during local pressure on skin (expected to be
less than 10 mmHg)
• Maximum measured value, expected briefly after release of the pressure. In
subjects
with dense vascularization this is expected to rise to a value that is only
slightly below the arterial oxygen tension (known to be about 100mmHg in
healthy adults). Because of the measurement principle (mitoPO2 ~ 1/lifetime)
larger variations are expected at higher oxygen tensions.
• Oxygen consumption
• PDT area size
• Pain
• Body weight
• Body length
• Body mass index
• Smoking, drug, alcohol
• Parameters influencing the microcirculation such as: Medication, vessel
diseases, ..
• Clinical efficacy of PDT treatment
• Skin type
Background summary
Photodynamic therapy (PDT) is used due to its minimally invasive character for
treatment of early stages of local, and superficial cancers in areas of the
body accessible for light application. Other applications for PDT are for
example actinic keratosis in dermatology, and macular degeneration in
ophthalmology. (Piffaretti et al., 2012)
The induced cell death by PDT relies on the presence of a photosensitizer
located in the target area, molecular oxygen and administration of light
absorbed by a photosensitizer. One of these photosensitizers is protoporphyrin
IX (PpIX), an endogenous mitochondrially produced photoactive molecule.
(Poulson, 1976; Treffry & Ainsworth, 1974). Photo-activated PpIX transforms the
triplet-ground state oxygen into singlet oxygen molecules. Singlet reactive
oxygen molecules are one of the main working mechanisms of PDT damaging the
mitochondria and internal cell organelles. (Allison & Moghissi, 2013, Buytaert,
Dewaele, & Agostinis, 2007, Morgan & Oseroff, 2001). Photodynamic therapy
therefore depends on the availability of oxygen in the cells of the target
tissue. It has so far not been possible to measure such cellular oxygen
availability.
Despite encouraging results with PDT some clinicians avoid using this therapy
due to observed fluctuations in intra- and inter-patient therapeutic outcomes.
(Radakovic-Fijan, Blecha-Thalhammer, Kittler, Hönigsmann, & Tanew, 2005) These
fluctuations generally are associated with the intra cellular oxygen level and
the uneven distributed photosensitizer. These uncertainties can be countered by
monitoring in real time available intracellular oxygen adjusting the light
dosimetry as ultimate result. (Busch, 2006; Glanzmann & Hadjur, 1998)
The possibility of measuring intra cellular oxygen during PDT may help improve
understanding of the mechanisms involved in the oxygenation and
photosensitization of biological tissues. (Piffaretti, 2011; Piffaretti et al.,
2012) It is likely that with this new information the efficacy and efficiency
of PDT for a specific patient can be indicated.
Study objective
Measure intracellular oxygen availability in humans during photodynamic therapy
Study design
Observational study
Study burden and risks
No extra riks are expected as result of the oxygen availability measurement. In
the volunteer study done in the Erasmus MC NL 37911.078.11.v06 / MEC-2001-397
only PDT effect were seen as adverse event (AE). No photodynamic effects are
reported with this device. These AEs were a result of careless behaviour
exposing the light sensitive area to sunlight. These effects are already
expected in PDT so no extra risks are identified. The extra burden for the
patient is small because the standard protocol is done with a few extra
measurements taking in total 150 min in which 120 min waiting time is included
between the therapy PDT sessions.
Wytemaweg 80
Rotterdam 3015CN
NL
Wytemaweg 80
Rotterdam 3015CN
NL
Listed location countries
Age
Inclusion criteria
Undergo 5-aminolevulinic acid precursor photodynamic therapy
Exclusion criteria
Less than 18 years of age
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL51187.078.14 |