Preface

In biology, senescence is a process by which cell ages and permanently stops dividing. Senescence is a natural universal phenomenon affecting all living organisms (e.g., humans, animals, and plants). The underlying mechanisms of senescence at the cellular level are not fully understood. Senescence is a multifactorial process that can be induced by several stimuli including cellular stress, DNA damage, telomere shortening, and oncogene activation. Senescence impacts the lifespan of living organisms. The lifespan ranges from a few hours (with mayfly) to potential eternity (with jellyfish and hydra). The maximum theoretical lifespan in humans is around 120 years. Senescence plays a role in the development of several age-related chronic diseases in humans (e.g., ischemic heart disease, osteoporosis, and cancer). Senescence is emerging as a therapeutic target for several diseases. Clinical trials using anti-senescent therapies are in progress. Results from early pilot studies suggest that senolytic drugs can decrease senescent cells, reduce inflammation, and alleviate frailty. This book provides the reader with a comprehensive overview of the current knowledge on the mechanisms and the management of senescence in humans together with comparative data on animals and plants.

The book contains six chapters by authors from Russia, Serbia, and the United States. I would like to thank all of them. I would also like to thank the great assistance of Ms. Dolores Kuzelj at IntechOpen who supervised this book project.

> **Hassan M. Heshmati, M.D.** Endocrinology Metabolism Consulting, LLC, Anthem, AZ, USA

Section 1
