This is a prospective, randomized, open label, parallel, 16-week study to explore and evaluate the therapeutic effects of Henagliflozin on the cognitive function, olfactory function, and odor-induced brain activation in T2DM patients with mild cognitive impairment (MCI).

This is a prospective, randomized, open label, parallel, 16-week study to explore and evaluate the therapeutic effects of Henagliflozin on the cognitive function, olfactory function, and odor-induced brain activation in T2DM patients with MCI inadequately controlled with metformin monotherapy. The control group was treated with Gliclazide. We have 1 principal investigator, 6 sub-investigators and 1 nurse in research centre. The sub-investigators will screen in the outpatient and inpatient departments to enroll 24 patients (12 patients for each arm) totally with the inclusion and exclusion criteria. The patients will be randomized at a 1:1 ratio into Henagliflozin and Gliclazide treatment group with a computer-generated random order. All patients will also continue on their existing dose and regimen of metformin throughout the study. At the baseline, clinical information collection, 100g-steamed bread meal test, biochemical measurement, body composition analysis, cognitive assessment, olfactory test and functional magnetic resonance imaging(fMRI) scan will be conducted for all patients. During the treatment period, visits at 8-week intervals will be performed to evaluate the safety of drugs and adjust the dose of metformin if hypoglycaemia occurs; meanwhile, fasting and 2-hour postprandial plasma glucose assayed by fingerstick, physical examination, and olfactory test will be conducted. At the end of the study, all of the assessments will be performed again for all recruited subjects, including early withdrawal patients.

Inclusion Criteria:

• patients with type 2 diabetes mellitus ;
• Aged: 55 - 75 years ;
• Cognitive function assessment suggests mild cognitive impairment;
• A stable glucose-lowering regimen include Metformin alone or in combination with antidiabetic drugs other than SGLT2 inhibitors or sulfonylureas/glinides, or basic insulin for more than 2 months, and the dose of metformin≥1.0g/d;
• HbA1c: 7 - 10%;
• ≥6 years of education;
• Right-handed.

Exclusion Criteria:

• Cognitive function assessment suggests normal cognition or dementia;
• Other dementia related neurological diseases or depression, Mental dysplasia, mania, schizophrenia, etc in the past 2 years; Central nervous system diseases, including brain trauma, intracranial hemorrhage, acute cerebral infarction, etc;
• Severe sinusitis, nasal cavity and sinus polyps, skull base or nasopharyngeal tumors and other space occupying lesions;
• Congenital diseases and traumatic history of nose, maxillofacial and skull base affecting olfaction.
• With symptoms of upper respiratory tract infection, including nasal congestion, runny nose, fever, etc. on the day of MR examination;
• Diabetic Acute and chronic complications, including diabetic ketoacidosis, diabetic ketoacidosis; a hyperglycemic hyperosmolar state or severe hypoglycemic coma, etc.
• Severe impairment of heart, liver, kidney and other organs;
• Contraindications of MRI examination, such as implantation of metal prosthesis in vivo, claustrophobia, etc;
• Pregnant and lactating women;
• Receive other test drugs currently or within 3 months before participating in the project;
• Known or suspected allergic history to the test drug or similar drugs; SGLT2 inhibitor and sulfonylureas/glinides were used in recent 3 months.