Kleitsas Aggelos is a Specialist in Internal Medicine – Diabetology and maintains a private practice in Kalamaria. He studied at the School of Medicine of Aristotle University of Thessaloniki. He then completed his rural service at the Health Center of Nea Moudania, Chalkidiki, followed by a five-year specialty in Internal Medicine under distinguished physicians of the 1st Internal Medicine Clinic of Agios Dimitrios Hospital in Thessaloniki. After obtaining his specialty, he trained in renal replacement therapy methods at the Nephrology Department of Hippokration Hospital in Thessaloniki. Subsequently, upon starting his private practice, he concurrently worked at the Hemodialysis Unit of Galinos Clinic during the period 2003-2005. In mid-2003, he began working at the IKA polyclinic in the Votsi area of Thessaloniki. He served there for 11 consecutive years and was the head of the clinic for the last two years. His education was further enriched with a two-year specialization in the complex field of diabetes mellitus at Papageorgiou Hospital during 2005-2007. Subsequently, after collaborating with the Medical Diavalkaniko Center of Thessaloniki, he served for three years as Director and Scientific Supervisor of the Internal Medicine Department at THERMI Clinic.