Irina Yu. Yanina

Destructive fat tissue engineering using photodynamic and selective photothermal effects

Destructive fat tissue engineering could be realized using the optical method, which provides reduction of regional or site-specific accumulations of subcutaneous adipose tissue on the cell level. We hypothesize that light irradiation due to photodynamic and selective photothermal effects may lead to fat cell lypolytic activity (the enhancement of lipolysis of cell triglycerides due to expression of lipase activity and cell release of free fat acids (FFAs) due to temporal cell membrane porosity), and cell delayed killing due to apoptosis caused by the induced fat cell stress and/or limited cell necrosis.

Fat tissue histological study at indocyanine green-mediated photothermal/photodynamic treatment of the skin in vivo

Histological slices of skin samples with the subcutaneous adipose tissue after photothermal/photodynamic treatment are analyzed. In the case of subcutaneous indocyanine green injection and 808-nm diode laser exposure of the rat skin site in vivo, the greatest changes in tissue condition were observed. Processes were characterized by dystrophy, necrosis, and desquamation of the epithelial cells, swelling and necrosis of the connective tissue, and widespread necrosis of the subcutaneous adipose tissue. The obtained data are useful for safe layer-by-layer dosimetry of laser illumination of ICG-stained adipose tissue for treatment of obesity and cellulite.

In vivo optical monitoring of transcutaneous delivery of calcium carbonate microcontainers.

We have developed a method for delivery of biocompatible CaCO3 microcontainers (4.0 ± 0.8 µm) containing Fe3O4 nanoparticles (14 ± 5 nm) into skin in vivo using fractional laser microablation (FLMA) provided by a pulsed Er:YAG laser system. Six laboratory rats have been used for the microcontainer delivery and weekly monitoring implemented using an optical coherence tomography and a standard histological analysis. The use of FLMA allowed for delivery of the microcontainers to the depth about 300 μm and creation of a depot in dermis. On the seventh day we have observed the dissolving of the microcontainers and the release of nanoparticles into dermis.

Fat tissue staining and photodynamic/photothermal effects

Cellulite is considered as a disease of the subcutaneous fat layer that appears mostly in women and consists of changes in fat cell accumulation together with disturbed lymphatic drainage, affecting the external appearance of the skin. The photodynamic and selective photothermal treatments may provide reduction the volume of regional or sitespecific accumulations of subcutaneous adipose tissue on the cellular level. We hypothesize that light irradiation of stained fat tissue at selected temperature leads to fat cell lypolytic activity (the enhancement of lipolysis of cell triglycerides due to expression of lipase activity and cell release of free fat acids (FFAs) due to temporal cell membrane porosity), and cell killing due to apoptosis caused by the induced fat cell stress and/or limited cell necrosis.

Photoinduced cell morphology alterations quantified within adipose tissues by spectral optical coherence tomography

Abstract. Morphological changes of the adipose tissue at phototreatment are studied in vitro using optical coherence tomography. The 200 to 600 μm fat tissue slices are used in the experiments. The observed change in the tissue structure was associated with fat cell lipolysis and destruction caused by the photodynamic effect. It is found that overall heating of a sample from room to physiological temperature leads to deeper and faster morphology tissue changes if other processing conditions are kept constant. These data support the hypothesis that photodynamic/photothermal treatment induces fat cell lipolysis during some period after treatment.

The morphology of apoptosis and necrosis of fat cells after photodynamic treatment at a constant temperature in vitro

Photodynamic therapy with temperature control is a new approach for treatment of obesity and cellulite. Cell death can occur under the action of various physical, chemical and biological factors. Depending on the inductor, this is apoptosis or necrosis. These two forms of cell death differ on the biochemical and morphological levels. Biochemical changes occur quickly enough and it raises difficulties of their detection. One of the morphological characteristics of apoptosis is a decrease (contraction) of cells, and necrosis - an increase in the size of the cell (swelling). This attribute simply determined visually using a digital microscope. The program was designed using LabVEIW media, which allowed us to develop the software for providing interaction with the measuring and control equipment, data collection, processing and displaying the information and results of calculations and simulations for the individual cells and ensembles of cells, and, in general, to automate process.

OPTICAL COHERENCE TOMOGRAPHY OF ADIPOSE TISSUE AT PHOTODYNAMIC/PHOTOTHERMAL TREATMENT IN VITRO

Temporal changes in structure and refractive-index distribution of adipose tissue at photodynamic/photothermal treatment were studied with OCT in vitro. Ethanol–water solutions of indocyanine green (ICG) and brilliant green (BG) were used for fat tissue staining. CW laser diode (808 nm) and LED light source (442 and 597 nm) were used for irradiation of stained tissue slices. The data received supporting the hypothesis that photodynamic/photothermal treatment, induces fat cell lipolysis during a certain period of time after light exposure.

Fat tissue histological study at NIR laser treatment of the skin in vivo

Histological slices of skin samples with the subcutaneous adipose tissue after laser irradiation at different doses are analyzed. These data may be used at carrying out of the analysis of histological slices of skin samples with the subcutaneous adipose tissue after photodynamic therapy. The obtained data are important for safe layer-by-layer dosimetry of laser irradiation used in the treatment of obesity and cellulite.

Diffusion of Cortexin and Retinalamin in eye sclera

Spectral measurements of sclera reflectance during its interaction with aqueous solutions of both Cortexin and Retinalamin have been carried out. Twenty three samples included in the study were human sclera and rabbit sclera in vitro. The results of the experiments have shown that penetration of Cortexin as well as Retinalamin into sclera tissue leads to the decrease of sclera reflection due to optical immersion. Estimation of diffusion coefficients of studied solutions was made on the basis of analysis of reflectance change dynamics of the sclera samples. Diffusion coefficients of Cortexin and Retinalamin in sclera tissue were estimated as (4.4±2.7)x10-6 and (1.82±0.14)x10-6 cm2/sec, respectively. Obtained values of diffusion coefficient allowed estimating time needed for total penetration of both agents through scleral membrane at subtenons injection of studied agents. The results are important for treatment of partial optic atrophy observed at primary open-angle glaucoma and others eye diseases.

Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry

Abstract. Observation of temperature-mediated phase transitions between lipid components of the adipose tissues has been performed by combined use of the Abbe refractometry and optical coherence tomography. The phase transitions of the lipid components were clearly observed in the range of temperatures from 24°C to 60°C, and assessed by quantitatively monitoring the changes of the refractive index of 1- to 2-mm-thick porcine fat tissue slices. The developed approach has a great potential as an alternative method for obtaining accurate information on the processes occurring during thermal lipolysis.