Jeffrey Peng, MD

All Publications

• Angiogenesis and Tissue Repair Depend on Platelet Dosing and Bioformulation Strategies Following Orthobiological Platelet-Rich Plasma Procedures: A Narrative Review. Biomedicines Everts, P. A., Lana, J. F., Onishi, K., Buford, D., Peng, J., Mahmood, A., Fonseca, L. F., van Zundert, A., Podesta, L. 2023; 11 (7)

  Abstract

  Angiogenesis is the formation of new blood vessel from existing vessels and is a critical first step in tissue repair following chronic disturbances in healing and degenerative tissues. Chronic pathoanatomic tissues are characterized by a high number of inflammatory cells; an overexpression of inflammatory mediators; such as tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1); the presence of mast cells, T cells, reactive oxygen species, and matrix metalloproteinases; and a decreased angiogenic capacity. Multiple studies have demonstrated that autologous orthobiological cellular preparations (e.g., platelet-rich plasma (PRP)) improve tissue repair and regenerate tissues. There are many PRP devices on the market. Unfortunately, they differ greatly in platelet numbers, cellular composition, and bioformulation. PRP is a platelet concentrate consisting of a high concentration of platelets, with or without certain leukocytes, platelet-derived growth factors (PGFs), cytokines, molecules, and signaling cells. Several PRP products have immunomodulatory capacities that can influence resident cells in a diseased microenvironment, inducing tissue repair or regeneration. Generally, PRP is a blood-derived product, regardless of its platelet number and bioformulation, and the literature indicates both positive and negative patient treatment outcomes. Strangely, the literature does not designate specific PRP preparation qualifications that can potentially contribute to tissue repair. Moreover, the literature scarcely addresses the impact of platelets and leukocytes in PRP on (neo)angiogenesis, other than a general one-size-fits-all statement that "PRP has angiogenic capabilities". Here, we review the cellular composition of all PRP constituents, including leukocytes, and describe the importance of platelet dosing and bioformulation strategies in orthobiological applications to initiate angiogenic pathways that re-establish microvasculature networks, facilitating the supply of oxygen and nutrients to impaired tissues.

  View details for DOI 10.3390/biomedicines11071922

  View details for PubMedID 37509560

• Electromyographic Characteristics of a Single Motion Shoulder Exercise: A Pilot Study Investigating a Novel Shoulder Exercise. International journal of sports physical therapy Henehan, M. J., Brand-Perez, T., Peng, J. C., Tsuruike, M. 2022; 17 (2): 270-275

  Abstract

  Background: Shoulder exercises focused on strengthening the rotator cuff and scapular stabilizing muscles as well as addressing scapular dyskinesis and motor control have been shown to improve rotator cuff function and decrease shoulder pain. A single motion shoulder exercise that effectively activates the rotator cuff and scapular stabilizing muscles, engages the scapulohumeral rhythm, and includes eccentric contractions may be more effective and easier for patients to consistently perform as compared to multiple standard shoulder exercises.Purpose: To compare the electromyographic muscle activation of key shoulder complex muscles during a single motion exercise and individual exercises (standard exercises) typically included in shoulder rehabilitation protocols.Study Design: Case-controlled, cohort study.Methods: Nineteen healthy men and women without shoulder pain or dysfunction were studied. Muscle activity of the rotator cuff and scapular stabilizing muscles (supraspinatus, infraspinatus, teres minor, trapezius [upper, middle and lower], serratus anterior, middle deltoid) was measured using surface EMG while subjects performed, in a standing position, several standard shoulder exercises typically included in shoulder rehabilitation protocols (resisted shoulder flexion, abduction in the scapular plane/scaption, external rotation, extension) and a single motion shoulder exercise consisting of a continuous movement creating the shape of "Figure of 8" in the transverse plane. The subjects used a weight between 5-15 pounds that produced muscle activation at 40-60% maximum voluntary isometric contraction (MVIC) for shoulder external rotation. That weight was then used for all of the exercises performed by the subject. The single highest EMG reading for each of the eight muscles studied, expressed as a percentage of MVIC, at any point during the second, third and fourth repetitions in a five repetition set was used to compare the single motion shoulder exercise and each exercise in the standard exercises set.Results: Ten men and nine women between 18-65 years of age were tested. No significant difference (p=.05) between the exercises was noted for the supraspinatus, infraspinatus, teres minor, serratus anterior, middle deltoid or upper trapezius. There was a significant difference favoring the standard exercises in the middle and lower trapezius. (p= 0.0109 and 0.0002 respectively).Conclusion: In this pilot study, muscle activation during the single motion, Figure of 8 pattern exercise was not significantly different from the standard shoulder exercises in six of eight key muscles that are usually included in shoulder rehabilitation protocols. The exceptions were the middle and lower trapezius which were activated to a significantly higher degree with the standard exercises. Further evaluation of the clinical effectiveness of the single motion shoulder exercise is needed.Level of Evidence: Level 3b.

  View details for DOI 10.26603/001c.31167

  View details for PubMedID 35136696