The Effects of Milnacipran on Sleep Disturbance in Fibromyalgia: A Randomized, Double-Blind, Placebo-Controlled, Two-Way Crossover Study.

OBJECTIVE: This study examined the effects of milnacipran on polysomnographic (PSG) measures of sleep and subjective complaints in patients with fibromyalgia and disturbed sleep. METHODS: This was a single-site, double-blind, placebo-controlled, two-period crossover PSG study. Eligible subjects (aged 28-72 y) were randomized (1:1) to milnacipran (100 mg/d) or placebo for crossover period 1, and vice versa for period 2. Each crossover period comprised a dose-escalation and dose-maintenance phase, with a 2-w taper/washout between periods. In-laboratory PSGs were collected at baseline, and at the end of each treatment period. The primary endpoints were the difference in PSG-recorded wake after sleep onset (WASO), number of awakenings after sleep onset (NAASO), and sleep efficiency (SE) between 4 w of maintenance treatment with milnacipran and placebo. Other PSG measures, subject-rated sleep, fatigue, physical functioning, and pain were assessed. Post hoc analysis was performed in subjects showing at least 25% reduction in pain from baseline in the Brief Pain Inventory Score (responders). RESULTS: Of 19 subjects randomized, 15 completed both periods. Subjects treated with milnacipran showed no significant improvements in WASO and NAASO, but showed reduced SE (p = 0.049). Milnacipran did not show significant improvement in other PSG parameters or subjective endpoints. Two thirds of completers met responder criteria and additionally showed a significant improvement in daily effect of pain (p = 0.043) and subjective sleep quality (p = 0.040). CONCLUSION: The data suggest that milnacipran is not sedating in most patients with fibromyalgia and improvements in sleep are likely a result of pain improvement. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT01234675.

PKCalpha regulates phosphorylation and enzymatic activity of cPLA2 in vitro and in activated human monocytes.

Phospholipases A(2) (PLA(2)) are potent regulators of the inflammatory response. We have observed that Group IV cPLA(2) activity is required for the production of superoxide anion (O(2)(-)) in human monocytes [Li Q., Cathcart M.K. J. Biol. Chem. 272 (4) (1997) 2404-2411.]. We have previously identified PKCalpha as a kinase pathway required for monocyte O(2)(-) production [Li Q., Cathcart M.K. J. Biol. Chem. 269 (26) (1994) 17508-17515.]. We therefore investigated the potential interaction between PKCalpha and cPLA(2) by evaluating the requirement for specific PKC isoenzymes in the process of activating cPLA(2) enzymatic activity and protein phosphorylation upon monocyte activation. We first showed that general PKC inhibitors and antisense oligodeoxyribonucleotides (ODN) to the cPKC group of PKC enzymes inhibited cPLA(2) activity. To distinguish between PKCalpha and PKCbeta isoenzymes in regulating cPLA(2) protein phosphorylation and enzymatic activity, we employed our previously characterized PKCalpha or PKCbeta isoenzyme-specific antisense ODN [Li Q., Subbulakshmi V., Fields A.P., Murray, N.R., Cathcart M.K., J. Biol. Chem. 274 (6) (1999) 3764-3771]. Suppression of PKCalpha expression, but not PKCbeta expression, inhibited cPLA(2) protein phosphorylation and enzymatic activity. Additional studies ruled out a contribution by Erk1/2 to cPLA(2) phosphorylation and activation. We also found that cPLA(2) co-immunoprecipitated with PKCalpha and vice versa. In vitro studies demonstrated that PKCalpha could directly phosphorylate cPLA(2).and enhance enzymatic activity. Finally, we showed that addition of arachidonic acid restored the production of O(2)(-) in monocytes defective in either PKCalpha or cPLA(2) expression. Taken together, our data suggest that PKCalpha, but not PKCbeta, is the predominant cPKC isoenzyme required for cPLA(2) protein phosphorylation and maximal induction of cPLA(2) enzymatic activity upon activation of human monocytes. Our data also support the concept that the requirements for PKCalpha and cPLA(2) in O(2)(-) generation are solely due to their seminal role in generating arachidonic acid.