Developing Cell Sheets for Myocardial Regenerative Treatments

Dr. Yoshiki Sawa
Professor of Cardiovascular Surgery, Surgical Medicine, Osaka University Graduate School of Medicine
Center Director of Medical Center for Translational Research, Osaka University Hospital
Doctor of Medicine
Dr. Yoshiki Sawa was born in 1955. In 1980, he graduated from the Osaka University Faculty of Medicine and entered the First Department of Surgery at Osaka University. In 1989, as a Humboldt Foundation Fellowship student, became an exchange student studying under the cardiac surgery and cardiac physiology departments of the Max-Planck Institute in Germany. After his return to Japan, he became an Assistant to the First Department of Surgery at the Osaka University Faculty of Medicine, a senior member of the medical staff and lecturer. Then in 2002, he became Associate Professor of the Department of Organ Regulation Medicine (First Department of Surgery) at the Osaka University Faculty of Medicine. He was also appointed Assistant Director of the University Hospital’s Medical Center for Translational Research. In 2004, he was appointed Assistant Chief of Cardiovascular Surgery at the Osaka University Hospital. In 2006, Dr. Sawa was appointed both Professor of Cardiovascular and Respiratory Surgery, Osaka University Graduate School of Medicine, and Director of Osaka University Hospital Medical Center for Translational Research.

The approach of the Medical Center for Translational Research of the Osaka University Hospital. As stated above, in addition to propelling the research directly toward the future of medical treatment, the center acknowledges the importance of translational research.

Before achieving this feat, Dr. Sawa also undertook research into regenerative treatments, working towards the establishment of a comprehensive system. In 2002, with the aim of translational research, he became the Assistant Director of the Medical Center for Translational Research, placed within the Osaka University Hospital. Through this management position, he was able to collaborate with the facilities and personnel required for regenerative treatment (in 2006 he became the Center Director).
In the culturing of the automyoblast cells that are essential to regenerative treatments, Dr. Sawa established the CPC (Cell Processing Center = cell culture manufacturing preparation facility) conforming to GMP (Good Manufacturing Practice). Furthermore, through the development and positioning of necessary staff, Dr. Sawa has used every possible means to build a comprehensive treatment system.
Regarding this development, Dr. Sawa was quoted as saying the following.
“As there has been no one before that has attempted this approach, we began by groping our way around blindly in the dark. Through the assistance and support of both the government and the pharmaceutical industry, we have finally been able to strengthen this system.
This center is a clinical research center that is a go-between that supports the development of new treatment methods aimed for the future. As this center is a facility of the University, research is not limited to fundamental research, but continues the investigation into steps to save critical patients with no other alternatives from a clinical standpoint. The ultimate objective of this center is to be a cell culturing factory that acts as a backup for regenerative treatments.”

Dr. Sawa is also a clinician in charge of outpatients. While sincerely facing critical patients, he feels strongly the need for regenerative treatments.

Dr. Sawa continues to vigorously progress his research with the aim of establishing the regenerative treatment of heart function. To save even one more critical patient with no other alternative, he is devoting himself to the speedy development of research treatments by increasing efficiency and decreasing the labor involved in his research. Of particular importance is the recruitment and training of the members of his research team.
According to Dr. Sawa, “it is important to, while fostering the young researchers, place the right people in the right positions and therefore heighten the motivation of each individual. By doing this, one plus one can equal three or more, and a research system with organizational strength can be created.” In addition to this, he is also taking into consideration the investment of facilities and equipment that may increase research efficiency.
He clearly states, “The key lies in reducing the amount of wasted time and effort during research activities. Particularly from the standpoint of competition on a global scale, speed is of the essence. Furthermore, I am fully aware that the faster we gain research results, the more beneficial to the patient.”
On the other hand, to break through to this previously unknown treatment method, Dr. Sawa points out “it is important to clarify the relationship between the benefits and risks involved in the introduction.” Speed but with poor results is unforgivable. Only when the relevance and safety of the treatment can be strictly proven during preclinical tests can the transition to human clinical trials be made possible. Dr. Sawa emphasizes the importance of “providing strict and objective evidence in the animal testing phase.”
Dr. Sawa, who as a young man acquired his doctorate by researching using an electron microscope, attaches great importance particularly in gathering evidence from a histological standpoint. “The conclusive factor that objectively proves whether, for example, cells have propagated, can depend on whether a definitive photograph has been taken. Of course, the numerical data of the experiment is also important, however, it is not an exaggeration to state that a single photograph can change the value of a thesis. For this reason alone, in the coming years it will become essential to use a microscope that links with the efficiency of observations and has superior abilities.” says Dr. Sawa.

Mr. Kenji Miki, operating the “BZ Series” in the laboratory

The man researching the regenerative treatment of myocardial functions on the basis of the research principles laid out by Dr. Sawa is Mr. Kenji Miki, who is currently enrolled in the Masters Course. He is undertaking research related to the formation process of everything from myoblast cells to myotube cells and over the past year has been observing the hearts of rats each and every day.
The device he is using to assist in this research is the KEYENCE BZ Series fluorescence microscope. The function of particular use is the multi-dimension time-lapse function, which can capture the images of cell changes over time. The myoblast cells transplanted onto the rat heart can be monitored to observe whether myocardial regeneration has occurred over time by capturing and saving these images. Furthermore, the Z-stack image capture, a function that can capture images along the vertical axis and generate a fully focused image, is also being used.

Differentiation-induced myocardial cells from iPS cells. The cytoskeleton is clearly stained.
(Image captured by the KEYENCE BZ Series)

In addition to the ease of observation, the BZ Series also exhibits a labor-saving benefit after images are captured. Up until now, Mr. Miki would first upload images taken to the PC, and then use image processing software to superimpose images with differing fluorescent colors. He would choose from a large volume of images the ones that were most focused, and then spend countless hours superimposing red, blue, and green fluorescent colored images. Despite the long hours, there was also no guarantee that the images were always clear.
In such a case, by using the best focus function of the BZ Series, the images with the best focus from the large volume captured on the Z-stack are automatically extracted. Furthermore, these extracted images can also be edited in chronological order. Mr. Miki admits “there were even times where an entire day was wasted simply on compiling images.” But after using the BZ Series, Mr. Miki explains, “processing can be completed in an hour, reducing the man-hours to 1/10th of the time that was previously needed.”
By substantially increasing the efficiency of observation, image capturing, and post-processing, Mr. Miki states that “we are now able to pursue research results with even higher accuracy.” This ability can be attributed to the wide range of experiments that can incorporate this device, making the work much easier. Observations that were previously abandoned, as they were too time-consuming, are now possible. Furthermore, the number of images captured, to prove research results, has been substantially increased. It can even be said that Mr. Miki—through the use of the BZ Series—is achieving the “objective proof” that Professor Sawa is seeking. Mr. Miki truly appreciates the image quality, as all images used in experiment records and for conference presentations have been captured using the BZ Series.