Muscle Fibers are Injured at the Time of Acute and Chronic Rotator Cuff Repair

Davis, M. Edward; Stafford, Patrick; Jergenson, Matthew J.; Bedi, Asheesh; Mendias, Christopher L.

doi:10.1007/s11999-014-3860-y

Cited by 34 publications

(37 citation statements)

References 27 publications

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“…Bilateral, chronic full-thickness supraspinatus tears and subsequent repairs after a period of twenty eight days were performed using sterile technique in a laminar flow hood [1, 9]. Postoperative care, antibiotics and analgesic medications were administered as described [1].…”

Section: Methodsmentioning

confidence: 99%

“…Postoperative care, antibiotics and analgesic medications were administered as described [1]. After the torn tendon was repaired, intramuscular injections of SVFCs that were isolated as described below and suspended in a vehicle of Lactated Ringers solution or vehicle alone were performed using a 25-gauge needle.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Surgical repair of torn rotator cuff muscles does not reverse fatty degeneration, and due to the shortening of the muscle that occurs in chronic tears, as much as 90% of muscle fibers can be injured at the time of surgical repair [1]. This massive second injury induced by repair can lead to further lipid infiltration and fibrosis which can further limit tissue regeneration and prevent full recovery [1, 2]. The fibrosis that commonly occurs in injured muscles increases the passive stiffness of the muscle extracellular matrix (ECM), and can also disrupt the lateral transmission of forces between muscle fibers, causing increased shearing and damage of the muscle fiber membrane [3].…”

Section: Introductionmentioning

confidence: 99%

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Stromal vascular stem cell treatment decreases muscle fibrosis following chronic rotator cuff tear

Gumucio

Flood

Roche

et al. 2015

International Orthopaedics (SICOT)

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PURPOSE Rotator cuff injuries are associated with atrophy and fat infiltration into the muscle, commonly referred to as "fatty degeneration." As the poor function of chronically torn muscles may limit recovery after surgical repair, there is considerable interest in finding therapies to enhance muscle regeneration. Stromal vascular stem cells (SVFCs) can improve muscle regeneration in other chronic injury states, and our objective was to evaluate the ability of SVFCs to reduce fibrosis and fat accumulation, and enhance muscle fiber specific force production after chronic rotator cuff tear. METHODS Chronic supraspinatus tears were induced in adult immunodeficient rats, and repaired one month following tear. Rats received vehicle control, or injections of 3×105 or 3×106 human SVFCs into supraspinatus muscles. RESULTS Two weeks following repair, we detected donor human DNA and protein in SVFC treated muscles. There was a 40% reduction in fibrosis in the treated groups compared to controls (p=0.03 for 3×105, p=0.04 for 3×106), and no differences between groups for lipid content or force production were observed. CONCLUSIONS As there has been much interest in the use of stem cell-based therapies in musculoskeletal regenerative medicine, the reduction in fibrosis and trend towards an improvement in single fiber contractility suggest that SVFCs may be beneficial to enhance the treatment and recovery of patients with chronic rotator cuff tears.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Stromal vascular stem cell treatment decreases muscle fibrosis following chronic rotator cuff tear

Gumucio

Flood

Roche

et al. 2015

International Orthopaedics (SICOT)

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“…It has been shown in a rat model that repairing either acutely or chronically torn rotator cuff tears cause damage to the muscle fibers and that the degree of injury is more severe in the chronically torn rotator cuff muscles 30 . Thus, we hypothesized that fatty infiltration and fibrosis would be present in a sheep model even after an acute repair six months following © C I C E d i z i o n i I n t e r n a z i o n a l i initial surgery.…”

Section: Discussionmentioning

confidence: 99%

Muscle atrophy and fatty infiltration after an acute rotator cuff repair in a sheep model

Liu

Easley

Ravishankar

et al. 2015

MLTJ

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Muscle atrophy and fatty infiltration after an acute rotator cuff repair in a sheep model tration, and fibrosis related genes. Significantly increased adipocytes, muscle fatty infiltration, and collagen deposition was observed in rotator cuff muscles in the tendon repair group compared to the control group. Conclusions: rotator cuff muscle undergoes degradation changes including fatty infiltration and fibrosis even after the tendons are repair immediately after rupture. Level of Evidence: Basic Science Study. IntroductionRotator cuff tears (RCTs) are the most common shoulder injury seen by orthopedic surgeons and are especially frequent among the aging patient population. The prevalence of full thickness RCTs is estimated between 15 and 51%, with higher rates in the elderly population 1 . Although repair of small tears is successful in alleviating pain and improving shoulder biomechanics, successful repair of larger RCTs still remains a challenge 2,3 . As the incidence of rotator cuff injuries continues to rise with an aging patient population, management and knowledge of the etiopathogenesis of RCTs 4 is a topic of concern. Several muscle-based factors have been identified to affect the outcome of rotator cuff repairs. It has been demonstrated that the degree of atrophy correlates with the size of the tear and, more importantly, with clinical outcomes 5,6 . Similarly, fatty infiltration has been shown to also correlate with poor outcomes following rotator cuff repair 6,7 . Although the clinical effects of muscle fibrosis on rotator cuff injuries are not well quantified, muscle fibrosis is an important contributor to muscle stiffness and is seen in many other muscle injury models 8 . Thus, these three physiological traits, muscle atrophy, fatty infiltration, and muscle fibrosis, are likely key factors governing outcome after rotator cuff injury and repair. Animal models are useful tools to study the molecular mechanisms of muscle atrophy, fatty infiltration, and fibrosis that are observed in the setting of rotator cuff tears in patients. While there are multiple RCTs studies conducted in rat or mouse models 9-12 , the sheep model, as a larger animal model, may more closely mirror the pathophysiologic changes observed in human RCTs 13 since the infraspinatus tendons of sheep SummaryIntroduction: rotator cuff tears (RCTs) are the most common tendon injury seen in orthopedic patients. Muscle atrophy and fatty infiltration of the muscle are crucial factors that dictate the outcome following rotator cuff surgery. Though less studied in humans, rotator cuff muscle fibrosis has been seen in animal models as well and may influence outcomes as well. The purpose of this study was to determine if the rotator cuff would develop muscle changes even in the setting of an acute repair in a sheep model. We hypothesized that fatty infiltration and fibrosis would be present even after an acute repair six months after initial surgery. Methods: twelve female adult sheep underwent an acute rotator cuff tear and immediate repair on ...

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Composition of Muscle Fiber Types in Rat Rotator Cuff Muscles

Rui

Pan²,

2016

The Anatomical Record

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The rat is a suitable model to study human rotator cuff pathology owing to the similarities in morphological anatomy structure. However, few studies have reported the composition muscle fiber types of rotator cuff muscles in the rat. In this study, the myosin heavy chain (MyHC) isoforms were stained by immunofluorescence to show the muscle fiber types composition and distribution in rotator cuff muscles of the rat. It was found that rotator cuff muscles in the rat were of mixed fiber type composition. The majority of rotator cuff fibers labeled positively for MyHCII. Moreover, the rat rotator cuff muscles contained hybrid fibers. So, compared with human rotator cuff muscles composed partly of slow-twitch fibers, the majority of fast-twitch fibers in rat rotator cuff muscles should be considered when the rat model study focus on the pathological process of rotator cuff muscles after injury. Gaining greater insight into muscle fiber types in rotator cuff muscles of the rat may contribute to elucidate the mechanism of pathological change in rotator cuff muscles-related diseases. Anat Rec, 299:1397-1401, 2016. © 2016 Wiley Periodicals, Inc.

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Muscle Fibers are Injured at the Time of Acute and Chronic Rotator Cuff Repair

Cited by 34 publications

References 27 publications

Stromal vascular stem cell treatment decreases muscle fibrosis following chronic rotator cuff tear

Stromal vascular stem cell treatment decreases muscle fibrosis following chronic rotator cuff tear

Muscle atrophy and fatty infiltration after an acute rotator cuff repair in a sheep model

Composition of Muscle Fiber Types in Rat Rotator Cuff Muscles

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