Insulin resistance is associated with aging in mice and humans. We have previously shown that administration of recombinant GDF11 (rGDF11) to aged mice alters aging phenotypes in the brain, skeletal muscle, and heart. While the closely related protein GDF8 has a role in metabolism, limited data are available on the potential metabolic effects of GDF11 or GDF8 in aging. To determine the metabolic effects of these two ligands, we administered rGDF11 or rGDF8 protein to young or aged mice fed a standard chow diet, short-term high-fat diet (HFD), or long-term HFD. Under nearly all of these diet conditions, administration of exogenous rGDF11 reduced body weight by 3–17% and significantly improved glucose tolerance in aged mice fed a chow (~30% vs. saline) or HF (~50% vs. saline) diet and young mice fed a HFD (~30%). On the other hand, exogenous rGDF8 showed signifcantly lesser effect or no effect at all on glucose tolerance compared to rGDF11, consistent with data demonstrating that GFD11 is a more potent signaling ligand than GDF8. Collectively, our results show that administration of exogenous rGDF11, but not rGDF8, can reduce diet-induced weight gain and improve metabolic homeostasis.

Purpose of Review: Notalgia paresthetica (NP) is a chronic cutaneous neuropathy primarily characterized by localized pruritus and associated dysesthesias, including sensations of pain, numbness, and tingling. The sensory neuropathy characteristic of NP is thought to result from spinal nerve entrapment caused by degenerative changes in the spine or musculoskeletal compression. This review summarizes the current medical literature with a focus on the past five years regarding NP, its pathophysiology, presentation, and current treatment options. Recent Findings: Though treatments exist with varying efficacy, to date, there exists no definitive treatment for NP. Treatment options for NP are varied and range from topical and oral agents to interventional procedures and physical therapy. Of the treatments evaluated, topical capsaicin remains the most efficacious treatment for NP. Conclusions: The lack of established treatment guidelines makes treating NP complicated as it dramatically affects patients’ quality of life. Further research with larger sample sizes is needed to evaluate better the most effective treatment and dosing regimen for patients afflicted with NP.