A Clinical Trial to Study the Efficacy and Safety of Different Doses of Bone Marrow Derived Mesenchymal Stem Cells in Patients With Critical Limb Ischemia Due to Buergers Disease

Inclusion Criteria: * Buerger's disease as diagnosed by Shionoya criteria * Males or females (willing to use accepted methods of contraception during the course of the study) in the age group of 18-65 yrs * Established CLI in the study limb, clinically and hemodynamically confirmed as per Rutherford- III-5 * Patients in Rutherford- III-6 if gangrene extending maximally up to the head of metatarsal but limited to toes (Patients with wet gangrene must undergo wound debridement / amputation before screening) * Patients having infrapopliteal occlusive disease with rest pain and ischemic ulcer/necrosis, who are not eligible for or have failed traditional revascularization treatment as per the investigators judgment (No option patients) * Ankle Brachial Pressure Index (ABPI) ≤ 0.6 or ankle pressure ≤ 50 mm Hg or TcPO2 ≤ 40 mmHg in the foot of the study limb * Patients who are able to understand the requirements of the study, and willing to provide voluntary written informed consent and video consent, abide by the study requirements, and agree to return for required follow-up visits Exclusion Criteria: * Patients with CLI indicated for major amputation during screening * Atherosclerotic PAD * Ulcers with exposure of tendon and/bone in the shin region * Previous above transmetatarsal amputation in study limb * Any Lumbar sympathectomy procedure performed less than 90 days prior to the screening * Patients with gait disturbance for reasons other than CLI * Diagnosis of diabetes mellitus (type 1 or type 2) * Patients having left ventricular ejection fraction \< 35% * Patients suffering from clinically relevant peripheral neuropathy * History of Stroke or myocardial infarction * Patients who are contraindicated for MRA * Patients with deep vein thrombosis in any limb * Patients who have clinically serious and/or unstable inter-current infection, medical illnesses or conditions that are uncontrolled or whose control, in the opinion of the Investigator, may be jeopardized by participation in this study or by the complications of this therapy * Documented terminal illness or cancer or any concomitant disease process with a life expectancy of \<1 year * Patients already enrolled in another investigational drug trial or completed within 3 months or those who have participated in any stem cell clinical trial * Patient with known hypersensitivity to the constituents of the IMP - dimethyl sulfoxide (DMSO) or human serum albumin (HSA) * History of severe alcohol or drug abuse within 3 months of screening * Hb% \< 10 gm% for males, Hb% \< 9 gm% for females, serum creatinine ≥ 2mg%, serum Total Bilirubin ≥2mg% * Pregnant and lactating women * Patients tested positive for HIV 1, HCV, HBV, CMV, RPR