Mesenchymal Stem Cells for The Treatment of Knee Osteoarthritis (KOA).

Inclusion Criteria: 1. Ambulatory subjects with osteoarthritis of the knee with symptoms for at least 3 months, that may be taking conservative therapy (e.g. oral anti-inflammatory medication), and/or undergoing physical therapy. In subjects with bilateral knee osteoarthritis, the more symptomatic knee will be the target knee. 2. Subjects of age between ≥40 through ≦ 90 years. 3. Subject diagnosed with knee osteoarthritis of grade II and III according to the Kellgren-Lawrence Grading Scale on the target knee. 4. Subject with joint pain equal or greater than 7 (total pain score 24 point) on the target knee assessed by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). 5. Subject or legal guardian is willing to provide written informed consent to participate in the study after reading the informed consent form and the information provided, and has had the opportunity to discuss the study with the investigator or designee. 6. Women of child-bearing potential should have a negative urine pregnancy test prior to administration of investigational product, and the subject must agree within at least 4 weeks after the study administration to use a double barrier method of birth control.UNLESS they meet the following criteria:(1) Post-menopausal: 12 months of natural (spontaneous) amenorrhea or 6 months of spontaneous amenorrhea with serum Follicle Stimulating Hormone (FSH) levels \> 40mIU/mL, OR; (2) 6 weeks post-surgical bilateral oophorectomy with or without hysterectomy. 7. If a male and heterosexually active with a female of childbearing potential, the subject must agree within at least 4 weeks after the study administration to use a double barrier method of birth control (or must have been surgically sterilized) and to not donate sperm. Exclusion Criteria: 1. Subjects with body mass index (BMI) over 40. 2. Subjects with knee deformity (knee varus or valgus greater than 10 degrees) on the target knee. 3. Subjects with acute inflammation or tense effusion (e.g., infection), or bleeding on the target knee as judged by principal investigator (PI). 4. Subjects with ligament instability (cruciate ligaments or collateral ligaments) or ligament laxity of the target knee as judged by PI. 5. Subjects with a history of surgery of articular injury, ligament reconstruction and meniscus repair on the target knee joint within previous 6 months. 6. Subjects with history of arthroscopic surgery in the target knee in the past 6 months or planned to have arthroscopy surgery during the trial period (e.g., scheduled for/awaiting arthroscopy or a knee replacement procedure) 7. Subjects with history of knee replacement procedure on the target knee. 8. Subjects with intra-articular infiltration of any treatments on the target knee (such as hyaluronic acid, corticosteroids or platelet rich plasma (PRP)) in the last 3 months prior to study inclusion. 9. Subjects with known history of osteoarthritis of hip or ankle. 10. Subjects with known history of any systemic autoimmune rheumatic disease including but not limited to: Reiter's syndrome, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, lymphoma, arthritis associated with inflammatory bowel disease, sarcoidosis or amyloidosis. 11. Subjects with Rheumatoid Factor levels (\>15.9 IU/mL) in laboratory tests. 12. Subjects with joint diseases (except knee osteoarthritis) or infectious arthritis on the target knee considered by investigator not eligible to enter the study. 13. Subjects who are known to be infected with HIV. 14. Subjects with active hepatitis B or active hepatitis C. 15. Subjects who have a significant concomitant illness as judged by principal investigator (PI) including, but not limited to: 1. Severe renal insufficiency (eGFR \< 30 mL/min/1.73 m2); or 2. hepatic (e.g. Child-Pugh Class C); or 3. Severe congestive heart failure (NYHA class 3 and 4); or 4. Severe pulmonary dysfunction, including severe chronic obstructive pulmonary disease (COPD) and history of lung resection; or 5. Any type of malignancy; or 6. Uncontrolled Diabetes Mellitus (HbA1c \> 10%) 16. Subjects with uncorrected hematology test including, but not limited to: 1. Hemoglobin \< 8 g/dl; or 2. White blood cell count \< 3,000/mm3; or 3. International normalized ratio (INR) of Coagulopathy \>1.5; or 4. Platelet count \< 80,000/mm3 17. Subjects who have the following conditions in laboratory tests: 1. \>2 × upper limit of normal for alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ; or 2. Total bilirubin \> 1.5 mg/dl 18. Subjects with known history of allergy or hypersensitivity to any component of investigational product, including dimethyl sulfoxide, cell therapies, or hyaluronic acid. 19. Subjects with known history of allergy or hypersensitivity to any concomitant medications, or rescue medications. 20. Subjects who have a significant skin disease at the injection site on target knee as judged by principal investigator (PI). 21. Subjects who are pregnant (or planning to become pregnant within 2 years of investigational product treatment) or lactating. 22. Participation in another clinical trial or treatment (e.g., immunosuppressant therapies, systemic steroids, cytotoxic drugs, chemotherapy, radiation therapy, new investigational drugs or cell therapy) within 3 months prior to inclusion in the study. 23. Contraindication to MRI: * Indwelling medical devices such as pacemakers, aneurysm clip, etc. * Indwelling metal from any other cause (trauma, etc.). To be excluded with history and/or radiographs, as necessary 24. Other pathologic conditions or circumstances that difficult participation in the study according to medical criteria.