A novel melanocortin fusion protein inhibits fibrinogen oxidation and degradation during trauma-induced coagulopathy.

Immune cell inflammation is implicated in the pathophysiology of acute trauma-induced coagulopathy (TIC). We hypothesized that leukocyte inflammation contributes to TIC through the oxidation and proteolysis of fibrinogen. To test this hypothesis, antioxidants and a novel anti-inflammatory melanocortin fusion protein (AQB-565) were used to study the effects of interleukin-6 (IL-6)-stimulated human leukocytes on fibrinogen using single-cell imaging flow cytometry and multiplex fluorescent western blotting. We also studied the effects of AQB-565 on fibrinogen using an in vivo rat trauma model of native TIC. IL-6 induced cellular inflammation and mitochondrial superoxide production in human monocytes, causing fibrinogen oxidation and degradation in vitro. Antioxidants suppressing mitochondrial superoxide reduced oxidative stress and inflammation and protected fibrinogen. AQB-565 decreased inflammation, inhibited mitochondrial superoxide, and protected fibrinogen in vitro. Trauma with hemorrhagic shock increased IL-6 and other proinflammatory cytokines and chemokines, selectively oxidized and degraded fibrinogen, and induced TIC in rats in vivo. AQB-565, given at the onset of hemorrhage, blocked inflammation, protected fibrinogen from oxidation and degradation, and prevented TIC. Leukocyte activation contributes to TIC through the oxidation and degradation of fibrinogen, which involves mitochondrial superoxide and cellular inflammation. Suppression of inflammation by activation of melanocortin pathways may be a novel approach for the prevention and treatment of TIC.

Slow Intravenous Infusion of a Novel Damage Control Cocktail Decreases Blood Loss in a Pig Polytrauma Model.

BACKGROUND: Our objective was to optimize a novel damage control resuscitation (DCR) cocktail composed of hydroxyethyl starch, vasopressin, and fibrinogen concentrate for the polytraumatized casualty. We hypothesized that slow intravenous infusion of the DCR cocktail in a pig polytrauma model would decrease internal hemorrhage and improve survival compared with bolus administration. METHODS: We induced polytrauma, including traumatic brain injury (TBI), femoral fracture, hemorrhagic shock, and free bleeding from aortic tear injury, in 18 farm pigs. The DCR cocktail consisted of 6% hydroxyethyl starch in Ringer's lactate solution (14mL/kg), vasopressin (0.8U/kg), and fibrinogen concentrate (100mg/kg) in a total fluid volume of 20mL/kg that was either divided in half and given as two boluses separated by 30 minutes as control or given as a continuous slow infusion over 60 minutes. Nine animals were studied per group and monitored for up to 3 hours. Outcomes included internal blood loss, survival, hemodynamics, lactate concentration, and organ blood flow obtained by colored microsphere injection. RESULTS: Mean internal blood loss was significantly decreased by 11.1mL/kg with infusion compared with the bolus group (p = .038). Survival to 3 hours was 80% with infusion and 40% with bolus, which was not statistically different (Kaplan Meier log-rank test, p = .17). Overall blood pressure was increased (p < .001), and blood lactate concentration was decreased (p < .001) with infusion compared with bolus. There were no differences in organ blood flow (p > .09). CONCLUSION: Controlled infusion of a novel DCR cocktail decreased hemorrhage and improved resuscitation in this polytrauma model compared with bolus. The rate of infusion of intravenous fluids should be considered as an important aspect of DCR.

Effects of estrogen and progesterone on spatial memory consolidation in aged females.

Interpretation of data illustrating that estrogen, with or without progestin, is detrimental to memory in post-menopausal women is complicated by the fact that little is known about the effects of progestins on memory. The present study examined if estrogen, alone or with progesterone, affects spatial memory consolidation in ovariectomized aged female mice. Mice received eight training trials in a spatial Morris water maze followed immediately by injection of water-soluble 17beta-estradiol (E(2); 0.2 mg/kg) or vehicle. Mice were re-tested 24 h later. All mice learned to find the platform on Day 1. On Day 2, the performance of control, but not E(2) mice, deteriorated, suggesting that E(2) enhanced memory for the platform location. In a second experiment, mice were injected with E(2) and 10 or 20 mg/kg water-soluble progesterone. The 10 mg/kg dose of progesterone did not affect estrogen's ability to enhance spatial memory consolidation, but 20 mg/kg blocked this effect. These data indicate that estrogen can improve spatial memory consolidation in aged females and that this effect can be attenuated by progesterone.

Long-term continuous, but not daily, environmental enrichment reduces spatial memory decline in aged male mice.

Although environmental enrichment improves spatial memory and alters synaptic plasticity in aged rodents, it is unclear whether all types of enrichment treatments yield similar benefits. The present study examined the effects in aged male mice of three types of enrichment on spatial memory in Morris water maze and radial arm maze tasks, and on levels of the presynaptic protein synaptophysin in several brain regions. Non-enriched young and aged males were compared with males exposed to one of the following treatments for 10 weeks: 5 min of daily handling, 3 h of daily basic enrichment, or 24 h of continuous complex enrichment. Young controls outperformed aged controls in both tasks. Neither daily handling nor daily enrichment affected spatial memory or synaptophysin levels. In contrast, continuous enrichment significantly reduced age-related spatial memory decline in both tasks, such that this group was statistically indistinguishable from young controls in most measures of performance. Continuously enriched mice were also significantly better than other aged mice in several spatial memory measures. Despite these improvements, synaptophysin levels in the continuous enrichment group were significantly lower than those of young and aged controls in the frontoparietal cortex, hippocampus, and striatum, suggesting a negative relationship between synaptophysin levels and spatial memory in aged males. These data demonstrate that different types of enrichment in aged male mice have disparate effects on spatial memory, and that the relationship between enrichment-induced changes in synaptophysin levels and spatial memory in aged males differs from that we have previously reported in aged female mice.

Behavioral training interferes with the ability of gonadal hormones to increase CA1 spine synapse density in ovariectomized female rats.

Estradiol benzoate (EB) has repeatedly been shown to increase hippocampal CA1 spine synapse density in ovariectomized female rats. Although this increase has been assumed to enhance memory, a direct link between increased spine synapse density and memory has not been demonstrated. Furthermore, while androgens, such as testosterone propionate (TP) and dihydrotestosterone (DHT), also increase spine synapse density in females, their effects on memory have yet to be investigated. In the present study, ovariectomized female rats were given two injections, 24 h apart, of sesame oil (control), 10 microg EB, 500 microg TP or 500 microg DHT. Forty-eight hours after the second injection, rats were tested in a 1-day spatial Morris water maze task and then immediately perfused for analysis of CA1 spine synapse density (using electron microscopy and unbiased stereology). In the spatial acquisition phase of testing, EB, but not TP or DHT, significantly impaired memory relative to controls. Hormone treatment did not affect spatial retention or performance in the non-spatial phase of testing. In contrast to previous work, spine synapse density was not increased by EB, TP or DHT. We therefore examined a new set of EB-treated females, only half of which were water maze tested. Consistent with previous work, EB significantly increased spine synapse density among behaviorally naïve females. In contrast, spine synapse densities did not differ among behaviorally tested control and EB females, although they were higher than behaviorally naïve controls. These data indicate that 1-day water maze testing can eliminate the hormone-induced increases in CA1 spine synapse density typically observed in behaviorally naïve females.