Anthony Kanai, PhD Associate Professor, Medicine
Dr. Kanai’s research focuses on the production and function of nitric oxide (NO) in the cardio-vascular system. This includes the mechanisms of shear stress evoked responses as well as other physiological and pathological mechanisms that regulate endothelial cell or cardiac myocyte signal transduction at the ion channel, second messenger and molecular level. This is accomplished using porphyrinic microsensor/macrosensor technology to directly measure in vitro and in vivo nitric oxide release from intact hearts or blood vessels, or the single cells or cellular compartments of those tissues. Dr. Kanai also employs cell isolation and culture, parallel-plate applied shear stress, fura-2 or rhod-2 fluorescent measurements of cellular Ca+2, pharmacology, histology, immuno-histochemistry and molecular biology. His porphyrinic microsensor/macrosensor technology is also particularly well suited to screening novel compounds that release nitric oxide themselves, modulate nitric oxide synthase, or evoke or inhibit nitric oxide release from cells. In collaboration with members of the Department of Surgery, Dr. Kanai has recently applied this technology to the study of inducible nitric oxide synthase (iNOS) gene therapy as a treatment for impotency and lower urinary tract dysfunction. Currently he is developing catheters to measure nitric oxide in the human heart, bladder and prostate. My current research involves the application of porphyrinic microsensor technology and/or Adenoviral vector mediated gene transfer to the following three projects: 1.) Characterization of cardiac cellular nitric oxide synthase (eNOS isoform) and mitochondrial nitric oxide synthase (mtNOS, isoform to be determined). We have just accomplished the first direct measurement of nitric oxide production by isolated mitochondria definitively demonstrating the presence of mtNOS in cardiac myocytes. A paper has just been submitted to Nature describing these findings. Another paper will be submitted shortly to Circulation Research regarding the characterization of the cellular eNOS. We are now shifting our attention to the effects of mitochondrially produced nitric oxide on the respiratory chain, especially its effects on cytochrome oxidase (complex IV). 2.) Study of Flow (Shear Stress and Pressure) evoked nitric oxide production in intact artery. We have recently determined that shear stress releases nitric oxide and pressure releases ATP from vascular endothelial cell. Furthermore, we have demonstrated that flow evokes a transient rather than continual production of nitric oxide that follows each wave of pulsatile flow. These findings are be submitted to Circulation Research.
3.) Study of the effectiveness of adenoviral vector mediated dystrophin gene transfer on failing hearts in dystrophin deficient (mdx) mice. These mice are models for muscular dystrophy. While Duchenne muscular dystrophy (DMD) and the less severe Becker muscular dystrophy (BMD) are generally thought of as skeletal muscle diseases, the patients also have cardiomyopathies. We have overcome one of the major problems in delivering the vector to the heart by injecting transdiaphragmatically into the pericardial sac. This mode of delivery increases the time that the heart is exposed to the vector and results in dystrophin restoration in 75-85 % of the heart. The results of this work is being submitted to Gene Therapy.