Metabolic activity in early tendon repair can be enhanced by intermittent pneumatic compression

Abstract

Since Achilles tendon healing is protracted, more knowledge of metabolites known to meet the demands for biosynthesis and proliferation is needed. We hypothesized that essential metabolites, glutamate, glucose, lactate, pyruvate and glycerol, are present and upregulated in healing Achilles tendons. We moreover hypothesized that adjuvant intermittent pneumatic compression (IPC), which increases blood flow, upregulates metabolite concentrations. Twenty patients with acute Achilles tendon rupture were recruited, operated, and included. The control group, 15 patients, received plaster cast immobilization, while five patients received adjuvant foot IPC beneath the plaster cast. At 2 weeks postoperatively, microdialysis of the healing and contralateral intact Achilles tendons was followed by quantification of metabolites. Healing compared to intact tendons of the controls exhibited significantly increased concentrations (mM) of glutamate (60 ± 14 vs 20 ± 11), lactate (1.15 ± 0.60 vs 0.64 ± 0.35), and pyruvate (81 ± 29 vs 35 ± 25, μM). Healing tendons of the IPC vs control group displayed higher levels of glutamate (84 ± 15 vs 62 ± 16) and glucose (3.44 ± 0.62 vs 2.62 ± 0.72); (P < 0.05) and trends toward higher concentrations of pyruvate, lactate, and glycerol (P < 0.10). The present study demonstrates that early Achilles tendon repair entails and upregulates local essential metabolites. This metabolic response can, during tendon healing with plaster cast immobilization, be promoted by adjuvant IPC.

Neuronal pathways in tendon healing and tendinopathy - update

“…Of all metabolites assessed during healing glutamate exhibited the highest elevation (102). This observation further strengthens the conception that the glutamatergic system is involved in regulating some aspects of proliferative tendon healing.…”

“…Axonal sprouting and growth and a time dependent expression of neuropeptides have been found to occur during healing of Achilles tendon rupture in the rat (Figure 4-6) (80, 103). Similar reactions can be observed in other tendons and in human tendon repair as well (29,102,104). The study presented was conducted using immunohistochemistry including a semi-quantitative assessment focusing on the rupture site of the proper tendinous tissue.…”

“…At two weeks post tendon injury, microdialysis followed by quantification demonstrated a 3-times up-regulation of glutamate levels in the paratenon of the healing tendon (102). Of all metabolites assessed during healing glutamate exhibited the highest elevation (102).…”

“…These results demonstrate that the compression treatment may have a substantial clinical impact, considering that immobilization is the basic principle in the treatment of ruptured tendons. In fact, clinical translation of the preclinical data has demonstrated that adjuvant intermittent pneumatic compression applied at least 6 hours daily for two weeks post human Achilles tendon rupture upregulated the concentration of local essential metabolites in the paratenon of the healing tendon (102). The metabolite exhibiting the largest elevation, 1.5-times, after adjuvant compression treatment was glutamate (102).…”

“…Peripheral glutamatergic regulation may be involved in the maintenance of tendon strength, cell proliferation, differention and in pathological cell transformation (97,99). Moreover, the peripheral glutamate signalling has been implicated in tendon tissue repair (101,102).…”