In vivosecond-harmonic generation andex vivocoherent anti-stokes raman scattering microscopy to study the effect of obesity to fibroblast cell function using an Yb-fiber laser-based CARS extension unit

Abstract

Nonlinear microscopy techniques are being increasingly used to perform in vivo studies in dermatology. These methods enable us to investigate the morphology and monitor the physiological process in the skin by the use of femtosecond lasers operating in the red, near-infrared spectral range (680-1,300 nm). In this work we used two different techniques that require no labeling: second harmonic generation (SHG) for collagen detection and coherent anti-Stokes Raman scattering (CARS) to assess lipid distribution in genetically obese murine skin. Obesity is one of the most serious public health problems due to its high and increasing prevalence and the associated risk of type 2 diabetes and cardiovascular diseases. Other than these diseases, nearly half of patients with diabetes mellitus suffer from dermatological complications such as delayed wound healing, foot ulcers and several other skin changes. In our experiment we investigated and followed the effects of obesity on dermal collagen alterations and adipocyte enlargement using a technique not reported in the literature so far. Our results indicate that the in vivo SHG and ex vivo CARS imaging technique might be an important tool for diagnosis of diabetes-related skin disorders in the near future.

Serum collagenase‐2 and BMI levels in pregnant women with striae gravidarum

“…It should be noted that increased subcutaneous fat tissue leads to structural changes in the dermis suppressing certain functions of fibroblasts . An increase in collagenase‐2 levels has been reported in obese children and adolescents . In another study, increased BMI was found to have a positive correlation with the level of collagenase‐2.…”

“…28 An increase in collagenase-2 levels has been reported in obese children and adolescents. 29 In another study, increased BMI was found to have a positive correlation with the level of collagenase-2. In the aforementioned study, an increased collagenase-2 level was reported to increase the risk of cardiovascular diseases.…”

Quantitative analysis of lipid debris accumulation caused by cuprizone induced myelin degradation in different CNS areas

“…To date, there is no specific data about the distribution and amount of myelin debris during the initiation of MS, although it might be a significant risk factor in launching inflammatory processes. To preserve chemical composition of myelin debris, we used the non-destructive coherent anti-Stokes Raman scattering (CARS) microscopy, a label-free imaging method capable of detecting specific molecules in living tissues by exciting the characteristic intrinsic vibrational frequency of its molecular bond (Cheng et al, 2002;Fu et al, 2008;Haluszka et al, 2015;Hellerer et al, 2007;Saar et al, 2010). We focused femtosecond pulsed laser beams combining 796 nm "pump" and 1028 nm "Stokes" beams to acquire excitation of vibration resonance of CH2 bonds of lipid molecules.…”

Handheld nonlinear microscope system comprising a 2 MHz repetition rate, mode-locked Yb-fiber laser for in vivo biomedical imaging

“…After optimizing our laser and imaging setup described above, we have performed a high number of in vivo SHG imaging measurements on the collagen content of living murine skin samples. Having in vivo human applications in mind, using this visual information a dermatologist can investigate tumor borders (e.g., in case of basal cell carcinoma [3]) or to follow biochemical processes in the human skin, such as the effects of obesity on dermal collagen alterations for instance [14]. SHG image of the collagen distribution in a murine skin shown in Fig.…”

“…In order to mention some possible applications in dermatology, we show that our novel microscope system is capable of high quality, in vivo SHG imaging of the collagen content of murine skin at average power levels as low as ~5 mW. Among others, using SHG imaging of the collagen, one can investigate basal cell carcinoma [3] or follow the effects of obesity on dermal collagen alterations [14] for instance. For demonstration purposes in cosmetology and nanomedicine, we also used our two-channel 2PEF/SHG imaging system for in vivo visualization and for monitoring the uptake of Alexa Fluor 546 labelled nanomedicine by Langerhans cells [15] for a few hours.…”