Kazuaki Muramatsu

The use of sonication treatment to completely decellularize blood arteries: A pilot study

We have developed a novel sonication decellularization system to prepare completely decellularized bioscaffolds in a short treatment time. The aim of the study is to investigate the sonication decellularization efficiency and its relation with ultrasonic power output and dissolved oxygen (DO) concentration in different detergent solution. In the study, we used aorta samples to evaluate sonication decellularization efficiency, which assessed treatment duration, sonication power and SDS detergent with/without saline. The treated samples were evaluated histologically by Hematoxylin Eosin (HE) staining and scanning electron microscopic (SEM) photographs. The concentration of DO was monitored to identify the effect of sonication on cavitation-related DO concentration in the solution. From histological results, the sonication decellularization efficiency was better than the other preparation methods. Decellularization efficiency was tended to increase significantly when DO value decreasing after 6 hours of treatment. In conclusion, we conclude that sonication treatment can be used to prepare the complete decellularized scaffolds in short treatment time.

PNPLA1 has a crucial role in skin barrier function by directing acylceramide biosynthesis

Mutations in patatin-like phospholipase domain-containing 1 (PNPLA1) cause autosomal recessive congenital ichthyosis, but the mechanism involved remains unclear. Here we show that PNPLA1, an enzyme expressed in differentiated keratinocytes, plays a crucial role in the biosynthesis of ω-O-acylceramide, a lipid component essential for skin barrier. Global or keratinocyte-specific Pnpla1-deficient neonates die due to epidermal permeability barrier defects with severe transepidermal water loss, decreased intercellular lipid lamellae in the stratum corneum, and aberrant keratinocyte differentiation. In Pnpla1−/− epidermis, unique linoleate-containing lipids including acylceramides, acylglucosylceramides and (O-acyl)-ω-hydroxy fatty acids are almost absent with reciprocal increases in their putative precursors, indicating that PNPLA1 catalyses the ω-O-esterification with linoleic acid to form acylceramides. Moreover, acylceramide supplementation partially rescues the altered differentiation of Pnpla1−/− keratinocytes. Our findings provide valuable insight into the skin barrier formation and ichthyosis development, and may contribute to novel therapeutic strategies for treatment of epidermal barrier defects.

Decellularization of Meniscal Tissue Using Ultrasound Chemical Process for Tissue-Engineered Scaffold Applications

Scaffolds play a key role in the process of regeneration and morphogenesis of tissue or organ. We have studied a novel application of ultrasound irradiation to prepare decellularized tissue for tissue-engineered scaffolds. The aim of the present study is to investigate the possibility of ultrasound energy on decellularization of cartilage tissue. The samples were decellularized using 20 kHz of ultrasonic irradiation in circulated 0.3% sodium chloride (NaCl) constituent of 2% sodium dodecyl sulfate (SDS) solution. To evaluate tissue integrity and cell removal, we used hematoxylin-eosin staining. To estimate the degree of irradiated ultrasound on the sample, we used computer simulation to calculate the irradiated power distribution in solution, corresponding to the irradiation energy against to the sample. From histological results, it shows that the ultrasonic power could assist the decellularization on meniscal tissue. The decellularization efficiency was better than the other preparation methods. Because of distributions of ultrasonic irradiation to samples were non-uniform, the efficiency of cell removal could be improved by using 3 dimensional scanning system which uniformly irradiate to the sample. In conclusion, ultrasonic chemical process has a potential to improve the efficiency of decellularization for menisci.

Dual Roles of Group IID Phospholipase A2 in Inflammation and Cancer

Phospholipase A2 enzymes have long been implicated in the promotion of inflammation by mobilizing pro-inflammatory lipid mediators, yet recent evidence suggests that they also contribute to anti-inflammatory or pro-resolving programs. Group IID-secreted phospholipase A2 (sPLA2-IID) is abundantly expressed in dendritic cells in lymphoid tissues and resolves the Th1 immune response by controlling the steady-state levels of anti-inflammatory lipids such as docosahexaenoic acid and its metabolites. Here, we show that psoriasis and contact dermatitis were exacerbated in Pla2g2d-null mice, whereas they were ameliorated in Pla2g2d-overexpressing transgenic mice, relative to littermate wild-type mice. These phenotypes were associated with concomitant alterations in the tissue levels of ω3 polyunsaturated fatty acid (PUFA) metabolites, which had the capacity to reduce the expression of pro-inflammatory and Th1/Th17-type cytokines in dendritic cells or lymph node cells. In the context of cancer, however, Pla2g2d deficiency resulted in marked attenuation of skin carcinogenesis, likely because of the augmented anti-tumor immunity. Altogether, these results underscore a general role of sPLA2-IID as an immunosuppressive sPLA2 that allows the microenvironmental lipid balance toward an anti-inflammatory state, exerting beneficial or detrimental impact depending upon distinct pathophysiological contexts in inflammation and cancer.

The Use of Sonication Treatment to Completely Decellularize Aorta Tissue

We have developed a novel sonication decellularization system to prepare completely decellularized bioscaffolds in a short treatment time. The aim of the study is to investigate the sonication decellularization efficiency and its relation with ultrasonic power output and dissolved oxygen (DO) concentration in different detergent solution. In the study, we used aorta samples to evaluate sonication decellularization efficiency, which assessed treatment duration, washing treatment after decellularization, SDS detergent with/without saline. The treated samples were evaluated histologically by Hematoxylin Eosin (HE) and diamidino-2-phenylindol (DAPI) stains. The concentration of DO was monitored to identify the effect of sonication on cavitation-related DO concentration in the solution. From histological results, the sonication decellularization efficiency was better than the other preparation methods. There were less than 2.0% of DNA remains after sonication decellularization treatment. Decellularization efficiency increased significantly which treated by sonication in SDS without saline as its DO value smaller compared with treatment in SDS with that. In conclusion, we conclude that sonication treatment is capable to use for preparation of the complete decellularized scaffolds in short treatment time.

Decellularization of Living Tissue Using Microwave Chemical Process for Tissue-Engineered Scaffold Applications

Scaffolds play a key role in the process of regeneration and morphogenesis of tissue or organ. We have studied a novel application of microwave radiation to prepare decellularized tissue for tissue-engineered scaffolds. The aim of the present study is to investigate the possibility of microwave effects on decellularization of soft and cartilage tissues. The targeted tissues were decellularized using 2450 MHz of microwave radiation in pulse-circulated 0.9% sodium chloride constituent of 1% sodium deoxycholate solution. To evaluate tissue integrity and cell removal, we used hematoxylin-eosin staining and scanning electron microscope. To investigate the effect of microwave power on targeted sample, we evaluate the radiated microwave distribution in microwave oven using thermograpic camera. Histological results suggest that microwave power influenced the decellularization of samples. It is significantly decellularized, when compared with the other preparation methods. Due to distributions of microwave radiation in the oven are non-uniform, the efficiency of cell removal can be improved by fitting the sample at uniform distribution and higher radiation spot of microwave. In conclusion, combination of microwave radiation and chemically detergent process has potential to decellularize various tissues, even tendon tissue. However, optimization of electromagnetic field in the oven is needed to perform in the further study to improve the decellularization efficiency.