This study explores the use of mesenchymal stem cells (MSCs) for intervertebral disc regeneration. We used an in vivo model to investigate the feasibility of exogenous cell delivery, retention, and survival in the pressurized disc space. MSC injection into rat coccygeal discs was performed using 15% hyaluronan gel as a carrier. Injections of gel with or without MSCs were performed. Immediately after injection, fluorescently labeled stem cells were visible on sections of cell-injected discs. Seven and 14 days after injection, stem cells were still present within the disc, but their numbers were significantly decreased. At 28 days, a return to the initial number of injected cells was observed, and viability was 100%. A trend of increased disc height compared to blank gel suggests an increase in matrix synthesis. The results indicate that MSCs can maintain viability and proliferate within the rat intervertebral disc.

Carotid duplex ultrasonography (DUS) is routinely performed prior to coronary artery bypass graft surgery (CABG) on all patients > 65 years old because of the reported associated risk of finding concomitant carotid artery stenosis. Identifying risk factors that correlate with severe carotid stenosis may result in more costeffective screening for patients with asymptomatic carotid artery disease prior to CABG. We performed a retrospective study to identify risk factors for significant carotid artery disease in patients scheduled to undergo CABG between March 2005 and March 2008 at the Massachusetts General Hospital. Patients with carotid stenosis ≥ 70% identified by DUS (n = 50) were matched by age and sex to control patients who had < 50% stenosis (n = 50). Data were analyzed using the chi-squared test or analysis of variance as appropriate. Logistic regression was used to examine multivariate correlates of carotid stenosis. A total of 643 patients were screened to arrive at the patient cohorts described below. This produced a prevalence of 7.7% for significant (> 70%) carotid disease. The patient cohorts were predominantly male with no significant difference in the incidence of diabetes, hypertension, extent of coronary artery disease (CAD) (i.e. left main coronary artery disease (LMCA) and one, two-, or three-vessel CAD) or lipid abnormalities in the two groups. Univariate analysis identified the presence of peripheral arterial disease (PAD, p = 0.001), a cervical bruit (p < 0.0001), a prior neurological event (p = 0.020), and the presence of an abdominal aortic aneurysm (AAA; p = 0.046) as significant predictors of ≥ 70% internal carotid artery stenosis. Logistic regression analysis revealed that the presence of a carotid bruit (p = 0.0068) and PAD (p = 0.0194) were associated with an increased risk of significant carotid artery disease. In conclusion, the presence of a carotid bruit or PAD predicts an increased likelihood of significant carotid artery disease in patients undergoing CABG. Unlike previous studies, LMCA or extent of CAD did not correlate with significant carotid artery disease. Using these predictive models, a prospective outcomes trial is required to validate these criteria.

No abstract