Endocrinology. 2011 Dec; 152(12): 4937-47
Bell JR, Mellor KM, Wollermann AC, Ip WT, Reichelt ME, Meachem SJ, Simpson ER, Delbridge LM

The conventional view is that estrogen confers female cardioprotection. Estrogen synthesis depends on androgen availability, with aromatase regulating conversion of testosterone to estradiol. Extragonadal aromatase expression mediates estrogen production in some tissues, but a role for local steroid conversion has not yet been demonstrated in the heart. This study's goal was to investigate how aromatase deficiency influences myocardial function and ischemic resilience. RT-PCR analysis of C57Bl/6 mouse hearts confirmed cardiac-specific aromatase expression in adult females. Functional performance of isolated hearts from female aromatase knockout (ArKO) and aromatase wild-type mice were compared. Left ventricular developed pressures were similar in aerobic perfusion, but the maximal rate of rise of ventricular pressure was modestly reduced in ArKO hearts (3725 ± 144 vs. 4272 ± 154 mm Hg/sec, P < 0.05). After 25 min of ischemia, the recovery of left ventricular developed pressure was substantially improved in ArKO (percentage of basal at 60 min of reperfusion, 62 ± 8 vs. 30 ± 6%; P < 0.05). Hypercontracture was attenuated (end diastolic pressure, 25 ± 5 vs. 51 ± 1 mm Hg; P < 0.05), and lactate dehydrogenase content of coronary effluent was reduced throughout reperfusion in ArKO hearts. This was associated with a hyperphosphorylation of phospholamban and a reduction in phosphorylated Akt. Immediately after reperfusion, ArKO hearts exhibited increased incidence of ventricular premature beats (194 ± 70 vs. 46 ± 6, P < 0.05). These observations indicate more robust functional recovery, reduced cellular injury, and modified cardiomyocyte Ca(2+) handling in aromatase-deficient hearts. Our findings indicate that androgen-to-estrogen conversion may be of pathophysiologic importance to the heart and challenge the notion that estrogen deficiency is deleterious. These studies suggest the possibility that aromatase suppression may offer inotropic benefit in the acute ischemia/reperfusion setting with appropriate arrhythmia management.

Fortschr Neurol Psychiatr. 2011 Oct; 79(10): 598-605; quiz 606
Finsterer J

J Neurosurg Anesthesiol. 2011 Oct; 23(4): 335-40
Johnsen D, Murphy SJ

Isoflurane exposure can protect the mammalian brain from subsequent insults such as ischemic stroke. However, this protective preconditioning effect is sexually dimorphic, with isoflurane preconditioning decreasing male while exacerbating female brain damage in a mouse model of cerebral ischemia. Emerging evidence suggests that innate cell sex is an important factor in cell death, with brain cells having sex-specific sensitivities to different insults. We used an in vitro model of isoflurane preconditioning and ischemia to test the hypothesis that isoflurane preconditioning protects male astrocytes while having no effect or even a deleterious effect in female astrocytes after subsequent oxygen and glucose deprivation (OGD).Sex-segregated astrocyte cultures derived from postnatal day 0 to 1 mice were allowed to reach confluency before being exposed to either 0% (sham preconditioning) or 3% isoflurane preconditioning for 2 hours. Cultures were then returned to normal growth conditions for 22 hours before undergoing 10 hours of OGD. Twenty-four hours after OGD, cell viability was quantified using a lactate dehydrogenase assay.Isoflurane preconditioning increased cell survival after OGD compared with sham preconditioning independent of innate cell sex.More studies are needed to determine how cell type and cell sex may impact on anesthetic preconditioning and subsequent ischemic outcomes in the brain.

Neuromuscul Disord. 2012 Feb; 22(2): 159-61
Sugai F, Baba K, Toyooka K, Liang WC, Nishino I, Yamadera M, Sumi H, Fujimura H, Nishikawa Y

We report a case of a 37year-old male with multiple acyl-CoA dehydrogenation deficiency (MADD). The patient had suffered from exercise intolerance in his hip and thigh muscles for one year. Then, restriction of carbohydrates for a diet made his symptoms rapidly deteriorate. Blood test revealed compound heterozygosity for two novel missense mutations in the electron transfer flavoprotein dehydrogenase gene (ETFDH), and an abnormal LDH isoenzyme pattern: LDH-1 (60.0%) and LDH-2 (26.0%) predominated with abnormally elevated LDH-1/LDH-2 ratio (2.3), compared with muscle-derived LDH-5 (4.0%). Oral riboflavin treatment significantly improved his exercise intolerance and the LDH profile: LDH-1 (34.4%), LDH-2 (34.9%), LDH-5 (6.9%) and LDH-1/LDH-2 ratio (1.0). The abnormal LDH isoenzyme pattern may be one feature of adult-onset MADD selectively affecting type I muscle fibers with relatively high LDH-1 content.

Biochim Biophys Acta. 2011 Nov; 1812(11): 1371-9
Verwaest KA, Vu TN, Laukens K, Clemens LE, Nguyen HP, Van Gasse B, Martins JC, Van Der Linden A, Dommisse R

Huntington disease (HD) is a hereditary brain disease. Although the causative gene has been found, the exact mechanisms of the pathogenesis are still unknown. Recent investigations point to metabolic and energetic dysfunctions in HD neurons. Both univariate and multivariate analyses were used to compare proton nuclear magnetic resonance spectra of serum and cerebrospinal fluid (CSF) taken from presymptomatic HD transgenic rats and their wild-type littermates. N-acetylaspartate (NAA), was found to be significantly decreased in the serum of HD rats compared to wild-type littermates. Moreover, in the serum their levels of glutamine, succinic acid, glucose and lactate are significantly increased as well. An increased concentration of lactate and glucose is also found in CSF. There is a 1:1 stoichiometry coupling glucose utilization and glutamate cycling. The observed increase in the glutamine concentration, which indicates a shutdown in the neuronal-glial glutamate-glutamine cycling, results therefore in an increased glucose concentration. The elevated succinic acid concentration might be due to an inhibition of succinate dehydrogenase, an enzyme linked to the mitochondrial respiratory chain and TCA cycle. Moreover, reduced levels of NAA may reflect an impairment of mitochondrial energy production. In addition, the observed difference in lactate supports a deficiency of oxidative energy metabolism in rats transgenic for HD as well. The observed metabolic alterations seem to be more profound in serum than in CSF in presymptomatic rats. All findings suggest that even in presymptomatic rats, a defect in energy metabolism is already apparent. These results support the hypothesis of mitochondrial energy dysfunction in HD.

Eur J Pharmacol. 2011 Nov 16; 670(1): 148-53
Qian Y, Guan T, Tang X, Huang L, Huang M, Li Y, Sun H

Maslinic acid is a triterpenoid compound present in plants of Olea europaea. This compound has been reported to have potent antioxidant, anti-cancer, anti-HIV and anti-inflammatory activities. In this study, we investigated the neuroprotective effect of maslinic acid and its mechanism of action. With presence or absence of maslinic acid, cortical neurons were subjected to 1h of oxygen-glucose deprivation and 24h of reoxygenation. Cell injury was determined by lactate dehydrogenase (LDH) measurement and 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay. Neuronal apoptosis was evaluated by flow cytometry assay, caspase-3 expression/activity, caspase-9 activity and Bcl-2/Bax ratio. Nitric Oxide (NO) production and inducible nitric oxide synthase (iNOS) expression were also detected. Results showed that maslinic acid dose-dependently ameliorated neuron injury and apoptosis. Maslinic acid treatment normalized the caspase expression/activation and increased the Bcl-2/Bax ratio. In addition, maslinic acid inhibited oxygen-glucose deprivation-induced NO production and iNOS expression. These results indicated that maslinic acid has beneficial effects on hypoxic neurons by suppressing iNOS activation, which may, in turn, provide neuroprotection.

Drug Chem Toxicol. 2011 Oct; 34(4): 440-4
Carlson GP

Styrene is known to be hepatotoxic and pneumotoxic in rodents, and these adverse effects are related to its metabolism. Mice deficient in the enzymes responsible for both the activation and detoxification of styrene are useful in examining this relationship more closely. In the current study, mice deficient in glutathione S-transferase P1P2(-/-) (GST(-/-)) were compared with wild-type mice. Similar changes in serum sorbitol dehydrogenase, as an indicator of hepatotoxicity, and bronchioalveolar levels of protein, cells, and lactate dehydrogenase, as indicators of pneumotoxicity, were observed after styrene administration. Glutathione depletion followed a similar pattern. The administration of the toxic metabolite, styrene oxide, which is a direct substrate for glutathione metabolism, and 4-vinylphenol, which is a minor metabolite but is more potent than either styrene oxide, yielded results similar to those of styrene. The results indicate that either other isoforms of glutathione S-transferase are more important than the P1P2 form in styrene detoxification or that this pathway contributes in only a minor way to styrene detoxification, compared to other pathways.

J Immunol. 2011 Aug 1; 187(3): 1467-74
Keating C, Pelegrin P, Martínez CM, Grundy D

The ATP-gated P2X(7) receptor (P2X(7)R) was shown to be an important mediator of inflammation and inflammatory pain through its regulation of IL-1β processing and release. Trichinella spiralis-infected mice develop a postinflammatory visceral hypersensitivity that is reminiscent of the clinical features associated with postinfectious irritable bowel syndrome. In this study, we used P2X(7)R knockout mice (P2X(7)R(-/-)) to investigate the role of P2X(7)R activation in the in vivo production of IL-1β and the development of postinflammatory visceral hypersensitivity in the T. spiralis-infected mouse. During acute nematode infection, IL-1β-containing cells and P2X(7)R expression were increased in the jejunum of wild-type (WT) mice. Peritoneal and serum IL-1β levels were also increased, which was indicative of elevated IL-1β release. However, in the P2X(7)R(-/-) animals, we found that infection had no effect upon intracellular, plasma, or peritoneal IL-1β levels. Conversely, infection augmented peritoneal TNF-α levels in both WT and P2X(7)R(-/-) animals. Infection was also associated with a P2X(7)R-dependent increase in extracellular peritoneal lactate dehydrogenase, and it triggered immunological changes in both strains. Jejunal afferent fiber mechanosensitivity was assessed in uninfected and postinfected WT and P2X(7)R(-/-) animals. Postinfected WT animals developed an augmented afferent fiber response to mechanical stimuli; however, this did not develop in postinfected P2X(7)R(-/-) animals. Therefore, our results demonstrated that P2X(7)Rs play a pivotal role in intestinal inflammation and are a trigger for the development of visceral hypersensitivity.

Diabetes. 2011 Jul; 60(7): 1946-54
Olerud J, Mokhtari D, Johansson M, Christoffersson G, Lawler J, Welsh N, Carlsson PO

Loss of thrombospondin (TSP)-1 in pancreatic islets has been shown to cause islet hyperplasia. This study tested the hypothesis that endothelial-derived TSP-1 is important for β-cell function.Islet function was evaluated both in vivo and in vitro. Messenger RNA and protein expression were measured by real-time PCR and Western blot, respectively. The role of endothelial-derived TSP-1 for β-cell function was determined using a transplantation design in which recipient blood vessels either were allowed to grow or not into the transplanted islets.TSP-1-deficient mice were glucose intolerant, despite having an increased β-cell mass. Moreover, their islets had decreased glucose-stimulated insulin release, (pro)insulin biosynthesis, and glucose oxidation rate, as well as increased expression of uncoupling protein-2 and lactate dehydrogenase-A when compared with control islets. Almost all TSP-1 in normal islets were found to be derived from the endothelium. Transplantation of free and encapsulated neonatal wild-type and TSP-1-deficient islets was performed in order to selectively reconstitute with TSP-1-positive or -negative blood vessels in the islets and supported that the β-cell defects occurring in TSP-1-deficient islets reflected postnatal loss of the glycoprotein in the islet endothelial cells. Treatment of neonatal TSP-1-deficient mice with the transforming growth factor (TGF)β-1-activating sequence of TSP-1 showed that reconstitution of TGFβ-1 activation prevented the development of decreased glucose tolerance in these mice. Thus, endothelial-derived TSP-1 activates islet TGFβ-1 of importance for β-cells.Our study indicates a novel role for endothelial cells as functional paracrine support for pancreatic β-cells.

Am J Physiol Lung Cell Mol Physiol. 2011 Aug; 301(2): L161-70
Rentsendorj O, Damarla M, Aggarwal NR, Choi JY, Johnston L, D'Alessio FR, Crow MT, Pearse DB

Phosphodiesterase 2A (PDE2A) is stimulated by cGMP to hydrolyze cAMP, a potent endothelial barrier-protective molecule. We previously found that lung PDE2A contributed to a mouse model of ventilator-induced lung injury (VILI). The purpose of the present study was to determine the contribution of PDE2A in a two-hit mouse model of 1-day intratracheal (IT) LPS followed by 4 h of 20 ml/kg tidal volume ventilation. Compared with IT water controls, LPS alone (3.75 μg/g body wt) increased lung PDE2A mRNA and protein expression by 6 h with a persistent increase in protein through day 4 before decreasing to control levels on days 6 and 10. Similar to the PDE2A time course, the peak in bronchoalveolar lavage (BAL) neutrophils, lactate dehydrogenase (LDH), and protein concentration also occurred on day 4 post-LPS. IT LPS (1 day) and VILI caused a threefold increase in lung PDE2A and inducible nitric oxide synthase (iNOS) and a 24-fold increase in BAL neutrophilia. Compared with a control adenovirus, PDE2A knockdown with an adenovirus expressing a short hairpin RNA administered IT 3 days before LPS/VILI effectively decreased lung PDE2A expression and significantly attenuated BAL neutrophilia, LDH, protein, and chemokine levels. PDE2A knockdown also reduced lung iNOS expression by 53%, increased lung cAMP by nearly twofold, and improved survival from 47 to 100%. We conclude that in a mouse model of LPS/VILI, a synergistic increase in lung PDE2A expression increased lung iNOS and alveolar inflammation and contributed significantly to the ensuing acute lung injury.

Eur J Pharmacol. 2011 Jun 1; 659(2-3): 224-32
Jing L, Wu Y, Wu J, Zhao J, Zuo D, Peng S

Previous studies have shown that metallothionein (MT) can antagonize the myocardiotoxicity induced by doxorubicin (Dox), a most effective anticancer agent. However, the molecular mechanisms are not well-understood. Using a proteomics approach we have detected that major peroxiredoxins (Prxs), an important redox regulating molecule family, may be involved in this process. In the present study, we assessed a link between metallothionein and peroxiredoxins. Wild-type (MT(+/+)) and MT(-/-) mice were treated intraperitoneally with doxorubicin at a single dose of 15 mg/kg and sacrificed on the 4th day after treatment. Doxorubicin induced cardiotoxicity in both wild-type and MT(-/-) mice was manifested with increased serum creatine kinase (CK) and lactate dehydrogenase (LDH) activities, and cardiac morphological changes. These toxic responses were stronger in the hearts of MT(-/-) mice that were more vulnerable to doxorubicin-induced oxidative injury as exhibited by increased lipid peroxidation and decreased catalase and glutathione peroxidase (GSH-Px) expression. Moreover, in the MT(-/-) mice, the deficiency of metallothionein inhibited the expression of Cu/Zn Superoxide dismutase (SOD-1) induced by doxorubicin. Doxorubicin significantly increased the mRNA levels and protein expressions of Prx-1, -2, -3, -5, and -6 in the hearts of wild-type but not MT(-/-) mice. Therefore, the present study suggests that metallothionein provides protection against doxorubicin-induced cardiotoxicity, which possibly involves regulation of peroxiredoxins.

Appl Environ Microbiol. 2011 Apr; 77(7): 2435-44
McNeely K, Xu Y, Ananyev G, Bennette N, Bryant DA, Dismukes GC

The nifJ gene codes for pyruvate:ferredoxin oxidoreductase (PFOR), which reduces ferredoxin during fermentative catabolism of pyruvate to acetyl-coenzyme A (acetyl-CoA). A nifJ knockout mutant was constructed that lacks one of two pathways for the oxidation of pyruvate in the cyanobacterium Synechococcus sp. strain PCC 7002. Remarkably, the photoautotrophic growth rate of this mutant increased by 20% relative to the wild-type (WT) rate under conditions of light-dark cycling. This result is attributed to an increase in the quantum yield of photosystem II (PSII) charge separation as measured by photosynthetic electron turnover efficiency determined using fast-repetition-rate fluorometry (F(v)/F(m)). During autofermentation, the excretion of acetate and lactate products by nifJ mutant cells decreased 2-fold and 1.2-fold, respectively. Although nifJ cells displayed higher in vitro hydrogenase activity than WT cells, H(2) production in vivo was 1.3-fold lower than the WT level. Inhibition of acetate-CoA ligase and pyruvate dehydrogenase complex by glycerol eliminated acetate production, with a resulting loss of reductant and a 3-fold decrease in H(2) production by nifJ cells compared to WT cells. Continuous electrochemical detection of dissolved H(2) revealed two temporally resolved phases of H(2) production during autofermentation, a minor first phase and a major second phase. The first phase was attributed to reduction of ferredoxin, because its level decreased 2-fold in nifJ cells. The second phase was attributed to glycolytic NADH production and decreased 20% in nifJ cells. Measurement of the intracellular NADH/NAD(+) ratio revealed that the reductant generated by PFOR contributing to the first phase of H(2) production was not in equilibrium with bulk NADH/NAD(+) and that the second phase corresponded to the equilibrium NADH-mediated process.