title: Effect of TheraCyte-encapsulated parathyroid cells on lumbar fusion in a rat model.
abstract: BACKGROUND
  Implantation of TheraCyte 4 × 10(6) live parathyroid cells can increase the bone marrow density of the spine of ovariectomized rats. There has been no published study examining the effect of such implantation on spinal fusion outcomes. The purpose of this study was to examine the effect of TheraCyte-encapsulated parathyroid cells on posterolateral lumbar fusions in a rat model.
  
  
  METHODS
  Forty Sprague-Dawley rats underwent single-level, intertransverse process spinal fusions using iliac crest autograft. The rats were randomly assigned to two groups: Group 1 rats received sham operations on their necks (control; N = 20); Group 2 rats were implanted with TheraCyte-encapsulated 4 × 10(6) live parathyroid cells into the subcutis of their necks (TheraCyte; N = 20). Six weeks after surgery the rats were killed. Fusion was assessed by inspection, manual palpation, radiography, and histology. Blood was drawn to measure the serum levels of calcium, phosphorus, and intact parathyroid hormone (iPTH).
  
  
  RESULTS
  Based on manual palpation, the control group had a fusion rate of 33 % (6/18) and the TheraCyte group had a fusion rate of 72 % (13/18) (P = 0.044). Histology confirmed the manual palpation results. Serum iPTH levels were significantly higher in the TheraCyte group compared with the control group (P < 0.05); neither serum calcium nor phosphorus levels were significantly different between the two groups.
  
  
  CONCLUSIONS
  This pilot animal study revealed that there were more fusions in rats that received TheraCyte-encapsulated 4 × 10(6) live parathyroid cells than in control rats without significant change in serum calcium or phosphorus concentrations. As with any animal study, the results may not extrapolate to a higher species. Further studies are needed to determine if these effects are clinically significant.
authors: Department of Orthopaedic Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors: Sung-Hsiung
authors: SH
authors: Chen
authors: Shun-Chen
authors: SC
authors: Huang
authors: Chun-Chung
authors: CC
authors: Lui
authors: Tzu-Ping
authors: TP
authors: Lin
authors: Fong-Fu
authors: FF
authors: Chou
authors: Jih-Yang
authors: JY
authors: Ko
mesh_terms: D000818:Animals; D017690:Cell Transplantation / Q000379:methods*; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D010280:Parathyroid Glands / Q000166:cytology* / Q000637:transplantation*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013123:Spinal Fusion / Q000379:methods*