title: In vitro characteristics of cultured posterior longitudinal ligament tissue.
abstract: METHODS
  To determine the osteogenicity of posterior longitudinal ligament ossification, the posterior longitudinal ligament obtained during anterior cervical surgery from patients with the disorder was analyzed with in vitro cultures.
  
  
  OBJECTIVE
  To determine the osteogenicity of the posterior longitudinal ligament.
  
  
  BACKGROUND
  The osteogenicity of posterior longitudinal ligament ossification in North America requires better documentation.
  
  
  METHODS
  The posterior longitudinal ligament obtained during anterior cervical corpectomy with fusion from seven patients, three with ossification of the posterior longitudinal ligament documented by magnetic resonance imaging and computed tomography and four with spondylosis, was blindly submitted for in vitro culture. Explants of the posterior longitudinal ligament were placed in Dulbecco modified Eagle medium with 10% fetal calf serum, antibiotics, 4 mmol/L x L-proline, and 50 mg/L ascorbic acid. After reaching confluency, cells were trypsinized, and first-passage cells were used for all osteocalcin measurements to establish their osteoblastic phenotype. Periosteal cells, previously shown to synthesize osteocalcin, were used as a positive control. The cells were incubated with 1,25(OH)2 vitamin D3 at 10E-8 M for 72 hours in serum-free medium. The supernatants were collected and frozen, after which the quantity of osteocalcin induced by exposure to 1,25(OH)2 vitamin D3 was determined using enzyme-linked immunoassay. Control replicate cultures were measured without incubation using vitamin D3.
  
  
  RESULTS
  Ossification of the posterior longitudinal ligament cell lines responded positively with osteocalcin synthesis in the 0.1 to 0.4 ng/M range. The cell line of the patient with spondylosis alone did not respond to vitamin D3 priming.
  
  
  CONCLUSIONS
  Posterior longitudinal ligament cells from the three North American white patients with ossification of the posterior longitudinal ligament, when cultured in vitro, synthesized osteocalcin on vitamin D3 priming, confirming their osteoblastic phenotype, whereas posterior longitudinal ligament cells from four white patients with isolated spondylosis did not.
authors.affiliation: Albert Einstein College of Medicine, Bronx, New York, USA. Don@psych.columbia.edu
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Epstein
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Grande
authors.forename: Arnold S
authors.initials: AS
authors.lastname: Breitbart
mesh_terms: D002117:Calcitriol / Q000494:pharmacology; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D016895:Culture Media, Serum-Free; D046508:Culture Techniques; D006801:Humans; D017846:Longitudinal Ligaments / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017887:Ossification of Posterior Longitudinal Ligament / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D015675:Osteocalcin / Q000032:analysis / Q000096:biosynthesis*; D010521:Periosteum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010641:Phenotype; D013128:Spinal Osteophytosis / Q000378:metabolism* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D044465:White People
chemical_list: D002120:Calcium Channel Agonists; D016895:Culture Media, Serum-Free; D015675:Osteocalcin; D002117:Calcitriol