Faculty Bibliography

Diabetic neuropathy is a debilitating disorder characterized by spontaneous and mechanical allodynia. The role of skin mechanoreceptors in the development of mechanical allodynia is unclear. We discovered that mice with diabetic neuropathy had decreased sirtuin 1 (SIRT1) deacetylase activity in foot skin, leading to reduced expression of brain-derived neurotrophic factor (BDNF) and subsequent loss of innervation in Meissner corpuscles, a mechanoreceptor expressing the BDNF receptor TrkB. When SIRT1 was depleted from skin, the mechanical allodynia worsened in diabetic neuropathy mice, likely due to retrograde degeneration of the Meissner-corpuscle innervating Aβ axons and aberrant formation of Meissner corpuscles which may have increased the mechanosensitivity. The same phenomenon was also noted in skin-keratinocyte specific BDNF knockout mice. Furthermore, overexpression of SIRT1 in skin induced Meissner corpuscle reinnervation and regeneration, resulting in significant improvement of diabetic mechanical allodynia. Overall, the findings suggested that skin-derived SIRT1 and BDNF function in the same pathway in skin sensory apparatus regeneration and highlighted the potential of developing topical SIRT1-activating compounds as a novel treatment for diabetic mechanical allodynia.

This pilot, double-blind, randomized, placebo-controlled study is aimed at evaluating the effectiveness of low-level laser therapy (LLLT) as a complementary treatment to complete decongestive therapy (CDT) treating lymphedema among breast cancer patients for 12 months post-intervention. Study population was breast cancer patients who were diagnosed and referred to lymphedema clinic for CDT. Participants (n = 22) were randomized and assigned into either an active laser intervention group or an inactive laser placebo-control group. Active LLLT was administered to participants twice a week at the beginning of each CDT session. Outcome measures included lymphedema symptoms, symptom distress, and limb volume by an infrared perometer. Participants in the active and placebo laser groups were comparable in demographic and clinical predictors of lymphedema. In comparison with the placebo group (83.3%), significantly fewer participants in the active laser group (55.6%) reported more than one lymphedema symptom (p = 0.012) at 12 months post-intervention. Significantly, more patients in the active laser group (44.4%) reported less than two impaired limb mobility symptoms in comparison with the placebo group (33.3%) at 12 months post-intervention (p = 0.017). The active laser group had statistically significant improvements in symptom distress of sadness (p = 0.005) from 73 to 11% and self-perception (p = 0.030) from 36 to 0% over time from baseline to 12-months post-intervention. There was no significant reduction in limb volume. Findings of the trial demonstrated significant benefits of complementary LLLT for relieving symptoms and improvement of emotional distress in breast cancer patients with lymphedema.