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Purpose: Erythropoietin is responsible for regulating the growth and development of red blood cells. Reports conflict on whether skeletal muscle is able to produce erythropoietin and release it into circulation and if exercise affects this. We set out to determine how erythropoietin is regulated in skeletal muscle and to determine whether skeletal muscle-derived erythropoietin can stimulate erythropoiesis. Methods: Using an in vitro approach, we exposed proliferating and differentiated skeletal muscle cells to various forms of exercise-induced physiological stimuli and measured erythropoietin gene expression. To understand if skeletal muscle cells were able to stimulate erythropoiesis, independent of other cell types found in skeletal muscle, we used myoblast-conditioned media to treat bone marrow and to measure erythropoiesis through flow cytometry. We also measured erythropoietin expression and hypoxia in mice subjected to an exercise protocol designed to induce skeletal muscle oxygen stress. Results: Hypoxia increased erythropoietin expression in C2C12 myoblasts, myotubes, and primary myoblasts in vitro by 50% to 130%. Bone marrow treated with media conditioned with hypoxic myoblasts for 24 h increased the number of Ter-119-positive cells by 32%. An erythropoietin-neutralizing antibody prevented this increase. Compared with unexercised controls, exhaustive exercise increased skeletal muscle HIF1α levels by 50% and HIF2α levels by 20%. Moreover, exercised skeletal muscle erythropoietin expression was 70% higher. Conclusion: These results demonstrate that skeletal muscle produces erythropoietin in a hypoxia and HIF-dependent manner and that hypoxia-treated muscle is capable of stimulating erythropoiesis in vitro. [ABSTRACT FROM AUTHOR]

Nipple pain and damage are commonly experienced by breastfeeding women and are associated with negative breastfeeding outcomes. Health care providers often recommend the application of lanolin to treat painful/damaged nipples, yet no randomized controlled trial has evaluated the effectiveness of lanolin on nipple pain and breastfeeding outcomes. The purpose of this study was to evaluate the effect of lanolin on nipple pain among breastfeeding women with damaged nipples. A randomized, single-blind, controlled trial was conducted at a tertiary care hospital in Hamilton, Ontario, Canada. Breastfeeding women ( N = 186) identified as having nipple pain/damage were randomized to apply lanolin (intervention group; n = 93) or to receive usual postpartum care (control group; n = 93). The primary outcome was nipple pain at 4 days post-randomization measured by the Numeric Rating Scale. Additional outcomes included nipple pain measured by the Short Form McGill Pain Questionnaire, breastfeeding duration/exclusivity, breastfeeding self-efficacy, and maternal satisfaction with lanolin treatment versus usual care. The results revealed no significant group differences in mean pain scores at 4 days post-randomization. Women in both groups experienced clinically relevant decreases in nipple pain by 7 days post-randomization. Significantly, more women in the lanolin group reported that they were satisfied with treatment compared with those receiving usual care. No significant group differences were found for other secondary outcomes. While more women were satisfied using lanolin, its application to sore/damaged nipples was ineffective for reducing nipple pain or improving breastfeeding outcomes. [ABSTRACT FROM AUTHOR]