title: In vitro assessment of cytotoxicity and labeling efficiency of 99mTc-HMPAO with stromal vascular fraction of adipose tissue.
abstract: BACKGROUND
  Noninvasive radionuclide imaging of cells using technetium99m-hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) is a potential diagnostic tool for several applications. Herein we aimed to evaluate the labeling efficiency and cellular toxicity of (99m)Tc-HMPAO with Stromal Vascular Fraction (SVF) of adipose tissue to develop a process tool for theranostic purposes, in particular imaging cardiac stem cell therapy.
  
  
  METHODS
  Ten million cells of SVF were labeled with (99m)Tc-HMPAO complex and excess radiolabel was cleared off through washing in PBS. The labeling efficiency of (99m)Tc-HMPAO was detected in labeled cells and their subsequent supernatant wash using isotope dose calibrator and gamma camera. The cytotoxicity was assessed for the comparative reactive oxygen species (ROS) by H2DCFDDA, apoptotic events by annexin-V and TUNEL assay and mitochondrial potential by JC-1.
  
  
  RESULTS
  An encouraging labeling efficiency of 33% was observed with (99m)Tc-HMPAO complex. The radionuclide labeling of SVF demonstrated significant safety profile as evaluated by apoptotic assays.
  
  
  CONCLUSIONS
  (99m)Tc-HMPAO labeling efficiency of 33% of total SV fraction would produce sufficient radioactive signals that would enable for in vivo tracking of cells by SPECT-CT. The radionuclide did not demonstrate any significant impact on the structural or functional organization of the labeled cells. Our study indicates that SVF can be safely labeled with (99m)Tc-HMPAO without adverse cytotoxic events and for its potential role in imaging cardiac stem cell therapy.
authors.affiliation: Department of Transplant Biology, Immunology & Stem Cell Lab, Global Hospitals, Hyderabad, India.
authors.forename: V K
authors.initials: VK
authors.lastname: Verma
authors.affiliation: Department of Transplant Biology, Immunology & Stem Cell Lab, Global Hospitals, Hyderabad, India.
authors.forename: S S
authors.initials: SS
authors.lastname: Beevi
authors.affiliation: KK Nuclear Scans, Raj Bhavan Road, Somajiguda, Hyderabad, India.
authors.forename: A
authors.initials: A
authors.lastname: Tabassum
authors.affiliation: KK Nuclear Scans, Raj Bhavan Road, Somajiguda, Hyderabad, India.
authors.forename: K
authors.initials: K
authors.lastname: Kumaresan
authors.affiliation: Department of Transplant Biology, Immunology & Stem Cell Lab, Global Hospitals, Hyderabad, India.
authors.forename: R S
authors.initials: RS
authors.lastname: Kamaraju
authors.affiliation: Cancer Centre, GA Regents University, Augusta, GA, USA.
authors.forename: A S
authors.initials: AS
authors.lastname: Arbab
authors.affiliation: Department of Transplant Biology, Immunology & Stem Cell Lab, Global Hospitals, Hyderabad, India. Electronic address: lkiran@globalhospitalsindia.com.
authors.forename: L K
authors.initials: LK
authors.lastname: Chelluri
mesh_terms: D000273:Adipose Tissue / Q000166:cytology* / Q000502:physiology / Q000528:radiation effects*; D002470:Cell Survival / Q000187:drug effects; D058948:Cell Tracking / Q000379:methods*; D002478:Cells, Cultured; D006801:Humans; D011829:Radiation Dosage; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000494:pharmacology; D013194:Staining and Labeling; D017154:Stromal Cells / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology; D019690:Technetium Tc 99m Exametazime / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime
keywords: (99m)Tc-HMPAO; Cardiac stem cell therapy; Cytotoxicity; Labeling efficiency; SVF