Rotator Cuff Tear Degeneration and Cell Apoptosis in Smokers Versus Nonsmokers

Abstract

Purpose-The purpose of this study was to assess the effect of smoking on supraspinatus tendon degeneration, including cellular alterations, proliferation, and apoptosis of tendon cells.Methods-Supraspinatus tendon samples of 10 smokers and 15 nonsmokers with full-thickness tears were compared, focusing on the severity of tendon histopathology including apoptosis (programmed cell death), cellularity, and proliferation. Immunohistochemistry was used to assess the density of apoptotic cells and proliferation. The extent of tendon degeneration was classified according to a revised version of the Bonar tendon histopathology score.Results-The smokers were younger (P = .01). The symptom duration among smokers was longer (P < .05). The supraspinatus tendons from the smokers presented significantly more advanced degenerative changes (Bonar score, 13.5 [interquartile range, 1.4] v 9 [interquartile range, 3]; P < .001). The smokers' tendons showed increased density of apoptotic cells (0.108 [SE, 0.038] v 0.0107 [SE, 0.007]; P = .024) accompanied by reduced tenocyte density (P = .019) and upregulation of proliferative activity (P < .0001). Conclusions-Smoking is associated with worsened supraspinatus tendon histopathology and increased apoptosis.Clinical Relevance-Pronounced degenerative changes, reduced tendon cellularity, and increased apoptosis may indicate reduced tendon healing capacity in smokers.

Nicotine impairs intra‐substance tendon healing after full thickness injury in a rat model

“…Similarly, histologic analysis also revealed no significant differences in cellularity, cell shape, or collagen fiber alignment. Overall, tendons from both groups demonstrated marked cellularity and rounding of tenocytes, consistent with previous literature . Given that there was no difference in cellularity or cell shape, the equivalent collagen fiber alignment between groups suggests that maturation of the healing tendon is not delayed in the nicotine treated group.…”

Impact of cardiovascular risk factor on the prevalence and severity of symptomatic full-thickness rotator cuff tears

“…This is an area of vascular anastomosis, plagued by microcirculatory disturbances and tissue hypoxia [14]. The oxidative stress due to production of reactive oxygen species and cellular apoptosis could be the cause of the degeneration, tendon ruptures and reduced number of tenocytes in patients who smoke [15].…”

What is the Role of Systemic Conditions and Options for Manipulation of Bone Formation and Bone Resorption in Rotator Cuff Tendon Healing and Repair?

“…100 Lundgreen et al found that supraspinatus tendon samples from smokers with full-thickness tears demonstrated increased density of apoptotic cells accompanied by reduced tenocyte density and upregulation of proliferative activity. 101 Given that the establishment of a vascular supply to the rotator cuff tendon is one of the critical factors in effective cuff healing, smoking as a pathologic mechanism for impaired healing is significantly supported.…”