Spontaneous spinal epidural hemorrhage and sentinel headache-A case report.

OBJECTIVES/BACKGROUND: Expand the differential diagnosis of sentinel headache to include spontaneous spinal epidural hematoma (SSEH) and reinforce the need for lumbar puncture in the evaluation of thunderclap headache. SSEH is a rare clinical presentation especially in the absence of bleeding tendencies. Clinicians recognize SSEH with typical presenting signs and symptoms including regional paraspinal muscular contraction and pain along with myelopathy. Although thunderclap headache usually does not connote vascular rupture in the spinal epidural compartment, SSEH may rarely present with sentinel headache and later evolve into a myelopathy. RESULTS AND CONCLUSION: Sentinel headache may be the sole symptom following spontaneous spinal epidural hemorrhage preceding both myelopathic and meningeal signs and symptoms. SSEH can best be diagnosed by lumbar puncture at this early moment potentially averting spinal cord injury.

Low-dose caffeine administration increases fatty acid utilization and mitochondrial turnover in C2C12 skeletal myotubes.

Caffeine has been shown to directly increase fatty acid oxidation, in part, by promoting mitochondrial biogenesis. Mitochondrial biogenesis is often coupled with mitophagy, the autophagy-lysosomal degradation of mitochondria. Increased mitochondrial biogenesis and mitophagy promote mitochondrial turnover, which can enhance aerobic metabolism. In addition, recent studies have revealed that cellular lipid droplets can be directly utilized in an autophagy-dependent manner, a process known as lipophagy. Although caffeine has been shown to promote autophagy and mitochondrial biogenesis in skeletal muscles, it remains unclear whether caffeine can increase lipophagy and mitochondrial turnover in skeletal muscle as well. The purpose of this study was to determine the possible contribution of lipophagy to caffeine-dependent lipid utilization. Furthermore, we sought to determine whether caffeine could increase mitochondrial turnover, which may also contribute to elevated fatty acid oxidation. Treating fully differentiated C2C12 skeletal myotubes with 0.5 mM oleic acid (OA) for 24 hr promoted an approximate 2.5-fold increase in cellular lipid storage. Treating skeletal myotubes with 0.5 mM OA plus 0.5 mM caffeine for an additional 24 hr effectively returned cellular lipid stores to control levels, and this was associated with an increase in markers of autophagosomes and autophagic flux, as well as elevated autophagosome density in TEM images. The addition of autophagy inhibitors 3-methyladenine (10 mM) or bafilomycin A1 (10 µM) reduced caffeine-dependent lipid utilization by approximately 30%. However, fluorescence and transmission electron microscopy analysis revealed no direct evidence of lipophagy in skeletal myotubes, and there was also no lipophagy-dependent increase in fatty acid oxidation. Finally, caffeine treatment promoted an 80% increase in mitochondrial turnover, which coincided with a 35% increase in mitochondrial fragmentation. Our results suggest that caffeine administration causes an autophagy-dependent decrease in lipid content by increasing mitochondrial turnover in mammalian skeletal myotubes.