Gridnyev Oleksiy has been working at the Institute since September 2004, as a scientific secretary of the Institute. He is also an employee of the department of the study of diseases of the digestive system and their comorbidity with the NID and co-performer of scientific works of the department from 2004 to the present time.

Leading researcher of the department of the study of diseases of the digestive system and their comorbidity with the NID, Doctor of Medical Sciences, Senior Researcher, Gastroenterologist of the first qualification category, Doctor-therapist of the highest qualification category.

Scientific experience - 18 years.

Clinical experience - 20 years.

Gridnyev O. studied the levels of apelin-12 and their relationship with sex, metabolites of nitric oxide, and daily blood pressure monitoring with combined gastroesophageal reflux disease (GERD) and arterial hypertension (AH) for the first time in Ukraine. For the first time in Ukraine the peculiarities of the histomorphological state of the mucous membrane of the esophagus during the comorbidity of GERD and AH were studied. The obtained data allowed us to develop models of prediction of the increase of AH in patients with comorbidity course of GERD and AH and to predict the development of erosive form of GERD in patients with comorbidity course of GERD and AH.

In addition, O. E. Gridnyev is well known among scientists and doctors for his scientific works of the study of comorbidity of digestive diseases with other diseases, including GERD and AH, GERD and obesity, non-alcoholic fatty liver disease and disorders of lipid metabolism, etc.

In recent years  O. E. Gridnyev develops a direction on the gut microbiome and its impact on the development of digestive diseases. He also develops a direction for the study of the effect of fecal microbiota transplantation in the treatment of diseases of the intestine and liver.

He was actively involved in the work of the European Group on the creation of a stool bank for fecal microbiota transplantation.

1. O. E. Gridnyev is the author of over 140 scientific papers, including the co-author of 14 monographs, reference books, guides and textbooks. Scientific Developments of Gridnyeva O. are protected by 4 intellectual property rights.
2. E. Gridnyev participates in the training of scientific personnel of higher qualification - under his leadership are completed 2 PhD theses.
3. E. Gridnyev is a member of the Ukrainian branch of the World Association of Gastroenterologists, the secretary of the Kharkiv branch of the NGO "Ukrainian Gastroenterology Association", the secretary of the Society of Gastroenterologists of the Kharkiv Scientific Society, a member of the Ukrainian Branch of the World Association of Gastroenterologists of the Society of Kharkov therapeutic journal "and" Modern Gastroenterology ".
4. E. Gridnyev was awarded the Certificate of Honor for significant contribution to the development of medical science and practice in 2013 and 2018, and the Certificate of Appreciation of the Presidium of the Academy of Medical Sciences of Ukraine in 2015 and 2017, and the Certificate of Honor of the Kharkiv City Council in 2019.
5. E. Gridnyev successfully combines scientific and administrative work with that of the Institute's Tender Committee, where he is the Deputy Chairman of the Institute's Tender Committee.

He is also active in organizing conferences that are held at the Institute. In addition, he is the Assistant Director of the Institute for Civil Protection and, on behalf of the Director of the Institute, regularly organizes practical classes on civil protection among the leadership of the Institute.