Male Tg Research Articles

Abstract 153: Inhibition of the 5-a-reductase Reduces Cardiac Hypertrophy and Improves Cardiac Function

Objectives: Left ventricular hypertrophy (LVH) is an independent risk factor for increased cardiovascular mortality and a precursor of heart failure. Gender-specific differences point to a pivotal role of androgens in the development of pathological LVH. Dihydrotestosterone (DHT) is metabolized from testosterone via the enzyme 5-α-reductase. The 5-α-reductase is upregulated in the hypertrophied myocardium, leading to our assumption that DHT rather than testosterone is the crucial component in the development of LVH and might therefore constitute a potential therapeutic target. Methods: One week after transverse aortic constriction (TAC) or sham surgery male wild-type mice were treated for 2 weeks via an oralgastric tube with the 5-α-reductase inhibitor finasteride (daily dose 25mg/kg BW) or were left untreated (controls). Male and female transgenic Gαq (TG, a model of dilative cardiomyopathy) or non-transgenic mice were treated with finasteride for 6 weeks. Results: Cardiac hypertrophy after TAC was dramatically reduced by finasteride in male mice (heart weight/ body weight ratio, HW/BW in mg/g: control 6.65±0.35 versus finasteride treated 5.23±0.3; p<0.01). The reduced hypertrophy in these mice was accompanied by a reduction in cardiomyocyte diameter, ANP expression and fibrosis, but increased capillary density and Serca2a expression. Accordingly, finasteride also markedly reduced hypertrophy in isolated primary rat cardiomyocytes in vitro . Amelioration of hypertrophy by finasteride was associated with blunted activation of the prohypertrophic kinase mTOR in vitro and in vivo . Left ventricular dilation in male Gαq TG mice was markedly reduced by treatment with finasteride, which also led to an improvement in left ventricular function (determined as fractional area change in % by echocardiography: finasteride 44.72±1.71 vs. control 32.8±3.84, p<0.05) and a similar trend was observed in female mice. Interestingly, finasteride reduced pulmonary congestion in male and female mice alike. Conclusion: Finasteride treatment reduces hypertrophy and eccentric cardiac remodelling in mice, indicating a possible involvement of DHT in these processes as well as a potential benefit of 5-α-reductase inhibition in cardiac disease.

Autophagy activation and neuroprotection by progesterone in the G93A-SOD1 transgenic mouse model of amyotrophic lateral sclerosis

Progesterone (PG) exerts neuroprotective effects under conditions such as brain ischemia, traumatic brain injury, and spinal cord injury. Previously, we reported that PG activates autophagy, a potential neuroprotective mechanism, in cortical astrocytes. In the present study, we explored the possibility that PG, by activating autophagy in spinal cord cells, protects against motoneuron degeneration in transgenic (Tg) mice expressing the human G93A-SOD1 (superoxide dismutase 1) mutant, a model of amyotrophic lateral sclerosis.PG treatment increased autophagic flux in G93A-SOD1 Tg spinal cord astrocyte cultures and mice. In addition, PG treatment reduced mutant SOD1 protein levels and motoneuronal death. Inhibition of autophagy with 3-methyladenine (3MA) reversed these PG effects, indicating that activation of autophagy contributed to the PG neuroprotection. PG effects in vivo were tested by intraperitoneally injecting male G93A-SOD1 Tg mice with different doses of PG (2, 4, or 8mg/kg) or vehicle from 70days of age until death. Measurements of motor functions using rota-rod tests showed that the onset of symptoms was not different among groups, but the progression of motor dysfunction was significantly delayed in the PG-treated group compared with the vehicle control group. The average lifespan was also prolonged in the PG-injected group. Histological examinations revealed that PG treatment substantially reduced the death of spinal motoneurons at 14weeks of age with a concomitant decrease in mutant SOD1 levels.Our results demonstrated that PG delays neurodegenerative progress in G93A-SOD1 transgenic mice, possibly through activation of autophagy in the spinal cord.

Hyperhomocysteinemia is an independent risk factor in young patients with coronary artery disease in southern China

Elevated plasma homocysteine (Hcy) is considered to be a risk factor of coronary artery disease (CAD), although this is still controversially discussed. This study investigated the role of Hcy in young patients with CAD in southern China. A total of 146 consecutive patients (aged ≤ 55years) with angiographically proven CAD were enrolled in the study and 138 age-matched non-CAD individuals were included as the control group. Hcy levels were measured by enzymatic assay. Hyperhomocysteinemia (HHcy) was defined as Hcy ≥ 15µmol/l. A 10-year CAD risk was calculated using the Framingham risk score (FRS) modified according to the National Cholesterol Education Program Adult Treatment Panel III. There were significant differences between the CAD and control groups with regard to male sex (P < 0.01), smoking history (P < 0.05), and triglyceride levels (TG, P < 0.05), but no remarkable difference in other conventional risk factors (all P > 0.05). Hcy and high-sensitivity C-reactive protein (hs-CRP) levels were significantly higher in the CAD group than those in the control group (both P < 0.05). The FRS and estimated 10-year absolute CAD event risk were low in both groups and did not show a statistical difference. Multivariate logistic regression showed that male sex (odds ratio, OR, 3.68; 95 % confidence interval, 95 % CI, 1.54-10.01), smoking (OR, 2.54; 95 % CI, 1.15-5.36), TG (OR, 1.30; 95 % CI, 1.08-3.06), hs-CRP (OR, 3.74; 95 % CI, 1.72-12.21), and HHcy (OR, 2.03; 95 % CI, 1.26-5.83) were independently correlated with CAD in young patients. HHcy is an important independent risk factor for CAD in young patients in southern China after adjusting for other risk factors.

818 ACTIVATION OF ANG II TYPE 1 RECEPTOR-ASSOCIATED PROTEIN SUPPRESSES VASCULAR HYPERTROPHY AND OXIDATIVE STRESS IN ANG II-MEDIATED HYPERTENSION

Objective: We cloned a novel molecule interacting with Ang II type 1 receptor, which we named ATRAP (for Ang II type 1 receptor-associated protein). The present study was designed to investigate the putative functional role of ATRAP in vascular hypertrophy and oxidative stress in Ang II-mediated hypertension in vivo. Methods & Results: We generated transgenic (Tg) mice expressing ATRAP in tissues including aorta under control of the β-actin promoter. The mRNA levels of ATRAP in Tg mice aorta were increased 15-fold compared with C57BL/6J Wild-type (Wt) mice. Adult male Wt mice and Tg mice at from 10 to 12 weeks of ages, were divided into two groups for the subcutaneous infusion of vehicle or Ang II 500ng/kg/min via osmotic mini-pump for 14days. Although systolic blood pressure was significantly elevated in the Ang II-infused mice, there was no significant difference in systolic blood pressure of Ang II-infused Tg mice compared to that of Ang II-infused Wild type mice. In Wt mice, the Ang II treatment promoted vascular hypertrophy in aorta, concomitant with a significant increase in aortic NADPH oxidase component, p22phox, expression. On the other hand, in ATRAP transgenic mice, the development of vascular hypertrophy and activation of p22phox in the context of Ang II treatment were significantly suppressed. Conclusions: These results demonstrate that activation of ATRAP at local tissue sites including aorta efficiently inhibits the vascular hypertrophy and oxidative stress provoked in Ang II-mediated hypertension, thereby suggesting ATRAP to be a novel therapeutic target in vascular disease.

A single-amino-acid variant of the H60 CD8 epitope generates specific immunity with diverse TCR recruitment.

TCR of CD8 T cells recognizes peptides of 8-9 amino acids in length (epitope) complexed with MHC class I. Peptide ligands differing from an epitope by one or two amino acids are thought to modulate the immune response specific to that epitope. H60 is a minor histocompatibility antigen for which the specific CD8 T-cell response dominates during alloresponse after MHC-matched allogeneic transplantation. In the present study, we developed a transgenic mouse (designated H60H Tg) expressing a variant of H60, designated H60H, in which the arginine residue at position 4 of the H60 epitope sequence (LTFNYRNL) is replaced by a histidine residue (LTFHYRNL). Immunization of female C57BL/6 mice with splenocytes from male H60H Tg induced a CD8 T cell primary response and memory response after re-challenge. The response was CD4 help-dependent, demonstrating the potency of H60H as a cellular antigen. The response induced by the H60H cellular antigen was comparable to that induced by H60 in its peak magnitude and overall immune kinetics. H60H challenge recruited broadly diverse TCRs to the specific response, shaping a TCR repertoire different from that of the natural H60 epitope. However, some of the TCRs did overlap between the H60H- and H60-specific CD8 T cells, suggesting that H60H might modulate the H60-specific response. These results may provide a basis for the modulation of the H60-specific CD8 T-cell response.

Abstract 17329: Myocardial-Specific Overexpression of a Dominant-Negative Mutant of NADPH Oxidase Subunit p67 phox Attenuates Pressure-Overload-Induced Cardiac Hypertrophy in Adult Transgenic Mice

We had reported a transgenic (Tg) mouse model with cardiac-specific overexpression of a dominant-negative (DN) mutant (V204A) of NADPH oxidase (NOX) subunit p67 phox that inhibits NOX activity. In order to test the role of NOX in pressure-overload-induced cardiac hypertrophy in young adult mice, age and body weight (BW)-matched male homozygous Tg and wild type (WT) C57BL/6 mice (10-12 weeks) were subjected to transverse aortic constriction (TAC) or sham operation. Four-week post TAC, 2-D echocardiography (echo) was performed to determine the following cardiac parameters: left ventricular myocardial area (LVMA); LV wall thickness at end diastole; LV internal dimension at end diastole (IDd), LV end-diastolic volume (EDV), LV ejection fraction (EF), LV mass &amp; aortic pressure gradient. Mice were divided into 4 groups (15-24 mice/group) including WT-sham, WT-TAC, Tg-sham &amp; Tg-TAC. The LVEDV, LVIDd &amp; BW were similar among all groups. The LVEF (mean 48-53%) was not statistically different among all groups. The aortic pressure gradient was between 30-60 mmHg in TAC mice and was statistically similar between the Tg and WT groups (45.3 ±1.7 vs. 50.4 ± 2.1 mmHg, p =0.1). Tg-sham showed no significant difference in LVMA, LV mass &amp; wall thickness vs. WT-sham (Table 1). The WT-TAC mice showed significant increase in LVMA, LV mass &amp; wall thickness indicating LV hypertrophy. The Tg-TAC mice also showed mild increase in the above parameters with the LV wall thickness statistically different from Tg-sham. However, these increases in Tg-TAC mice were significantly ( p &lt;0.05) smaller than those in WT-TAC mice, suggesting TAC-induced LV hypertrophy was attenuated in Tg mice. Our echo finding was also confirmed by our results of heart weight/BW ratio, ANF mRNA expression, and histological study of the LV myocardium. In summary, our results showed that selective inhibition of myocardial NOX subunit p67 phox attenuated chronic pressure-overload-Induced cardiac hypertrophy in young adult mice.

Abstract 17040: Selective Inhibition of Myocardial NADPH Oxidase with a Dominant-Negative Mutant of p67 phox Attenuates Angiotensin II-Induced Cardiac Hypertrophy in Adult Transgenic Mice

Angiotensin (Ang) II infusion not only induces hypertrophy and fibrosis in mouse heart, but also causes hypertension and inflammation in vivo. Thus, the precise mechanisms of Ang II-induced cardiac hypertrophy are unclear. Recently, selective inhibition of Ang II receptor in vivo was reported to attenuate the increase of expression of myocardial NADPH oxidase (NOX) subunits including p67 phox in heart failure rats. To study the endogenous “cardiac” NOX role in vivo, we created a transgenic (Tg) mouse model with cardiac-specific overexpression of a dominant-negative (DN) mutant (V204A) of NOX subunit p67 phox that prevented NOX activity. Age- and body weight (BW)-matched male Tg or WT C57BL/6 mice (12-14 weeks) were infused with either PBS or Ang II (0.7 mg/kg/day) for 2 weeks by an osmotic mini-pump. Echocardiography (echo) was then performed to determine the following parameters: left ventricular myocardial area (LVMA); LV wall thickness at end diastole; LV internal dimension at end diastole (IDd), LV end-diastolic volume (EDV), LV ejection fraction (EF), and LV mass. Mice were divided into 4 groups (6-8 mice/group) including WT-PBS, WT-Ang, Tg-PBS &amp; Tg-Ang. The LVEDV, LVIDd &amp; BW were similar between the PBS and Ang groups in both WT and Tg mice. The LVEF (mean 49-52%) was not statistically different among all groups. The WT-Ang mice showed significant increase in LVMA, LV mass &amp; wall thickness indicating LV hypertrophy compared to WT-PBS. In contrast, Tg-Ang showed no significant difference in LVMA, LV mass &amp; wall thickness vs. Tg-PBS, suggesting Ang-induced LV hypertrophy was inhibited in Tg mice (Table 1). Our echo data were confirmed by our results of heart weight (HW)/BW ratio and myocardium reactive oxygen species (ROS) measurement, showing the attenuation of the increase of both HW/BW ratio and ROS in TG-Ang mice vs. WT-Ang mice. In summary, our results showed that selective inhibition of myocardial NOX/p67 phox attenuates Ang II-Induced cardiac hypertrophy in Tg mice.

Thioredoxin 1 Overexpression Extends Mainly the Earlier Part of Life Span in Mice

We examined the effects of increased levels of thioredoxin 1 (Trx1) on resistance to oxidative stress and aging in transgenic mice overexpressing Trx1 [Tg(TRX1)(+/0)]. The Tg(TRX1)(+/0) mice showed significantly higher Trx1 protein levels in all the tissues examined compared with the wild-type littermates. Oxidative damage to proteins and levels of lipid peroxidation were significantly lower in the livers of Tg(TRX1)(+/0) mice compared with wild-type littermates. The survival study demonstrated that male Tg(TRX1)(+/0) mice significantly extended the earlier part of life span compared with wild-type littermates, but no significant life extension was observed in females. Neither male nor female Tg(TRX1)(+/0) mice showed changes in maximum life span. Our findings suggested that the increased levels of Trx1 in the Tg(TRX1)(+/0) mice were correlated to increased resistance to oxidative stress, which could be beneficial in the earlier part of life span but not the maximum life span in the C57BL/6 mice.

Increased oxidative stress, the renin–angiotensin system, and sympathetic overactivation induce hypertension in kidney androgen-regulated protein transgenic mice

Gender differences in the incidence and severity of hypertension have suggested the involvement of a sex-dependent mechanism. Transgenic (Tg) mice overexpressing kidney androgen-regulated protein (KAP) specifically in kidney showed hypertension associated with oxidative stress. Reactive oxygen species (ROS) are strongly implicated in the pathological signaling leading to hypertension in a framework that includes renin–angiotensin system (RAS) activation, increased sympathetic activity, and cardiac remodeling. In this report, we observed that plasma levels of angiotensin II and catecholamines were increased in KAP Tg mice, compared with wild-type animals. Systemic administration of Tempol, a membrane-permeative superoxide dismutase mimetic, reduced arterial pressure as well as urinary excretion of oxidative stress markers and reduced both angiotensin II and norepinephrine plasma levels in KAP Tg mice. Intracerebroventricular administration of Tempol also reduced arterial pressure in Tg mice. Moreover, administration of apocynin and DPI, inhibitors of NADPH oxidase, a major source of ROS, also reduced arterial pressure and both angiotensin II and norepinephrine plasma levels in Tg mice. Thus, we analyzed the involvement of the RAS and sympathetic nervous system in KAP Tg mouse hypertension. Both captopril and losartan reduced arterial blood pressure in Tg mice, as also occurred after β-adrenergic blockade with atenolol. Also, intracerebroventricular losartan administration reduced arterial pressure in KAP Tg mice. Our data demonstrate that hypertension in male KAP Tg mice is based on increased oxidative stress, increased sympathetic activity, and RAS activation. Moreover, our results suggest a role for increased oxidative stress in the CNS as a major cause of hypertension in these animals.

P2-S5.09 Transgenders and HIV: a literature review of HIV risk behaviours and prevalence rates

BackgroundTransgenders (TG) are a marginalised population that has been greatly impacted by the HIV/AIDS epidemic. The objective of this study is to review the current literature citing risk factors and...

Subcellular effects of myocyte-specific androgen receptor overexpression in mice

Although androgen receptor (AR) within myocytes is thought to mediate many of the effects of testosterone and other androgens on skeletal muscle, little is known about the functions of AR within these cells. We, therefore, studied the ultrastructure of skeletal muscle of HSA-AR transgenic (Tg) mice that overexpress AR selectively in myocytes and exhibit neuromuscular atrophy. We examined male HSA-AR mice from two different founding lines: L78 (lower copy number and less severe phenotype) and L141 (higher copy number and more severe phenotype) and compared these to wild-type (Wt) brothers. We also examined testosterone-treated female mice from these two lines and compared them both to their Wt sisters and to vehicle-treated controls. Ultrastructural examination of extensor digitorum longus sections using transmission electron microscopy revealed remarkably disorganized myofibrils in male Tg and testosterone-treated female Tg mice. Quantification of ultrastructural pathology indicated reduced myofibril width, hypertrophic and hyperplastic intermyofibrillar mitochondria, and pronounced glycogen accumulation in HSA-AR males of both lines. Reduced myofibrillar width and increases in mitochondrial number, size, and volume density were also observed in testosterone-treated HSA-AR females, although glycogen accumulation was not observed. Structural abnormalities in mitochondria were also associated with increases in electron transport chain activity and systemic resting metabolic rate, indicative of hypermetabolism. We find that overexpression of AR in myocytes of HSA-AR mice results in alterations in myofibrils, mitochondria, and glycogen. Alterations in myofibrils and mitochondria appear to result from acute actions of testosterone, whereas those on glycogen do not. Pathology of myofibrils and/or mitochondria may, therefore, mediate in part the neuromuscular atrophy observed in HSA-AR mice.

Mineralocorticoid receptor blockade improves diastolic function independent of blood pressure reduction in a transgenic model of RAAS overexpression

There is emerging evidence that aldosterone can promote diastolic dysfunction and cardiac fibrosis independent of blood pressure effects, perhaps through increased oxidative stress and inflammation. Accordingly, this investigation was designed to ascertain if mineralocorticoid receptor blockade improves diastolic dysfunction independently of changes in blood pressure through actions on myocardial oxidative stress and fibrosis. We used young transgenic (mRen2)27 [TG(mRen2)27] rats with increases in both tissue ANG II and circulating aldosterone, which manifests age-related increases in hypertension and cardiac dysfunction. Male TG(mRen2)27 and age-matched Sprague-Dawley rats were treated with either a low dose (∼1 mg·kg(-1)·day(-1)) or a vasodilatory, conventional dose (∼30 mg·kg(-1)·day(-1)) of spironolactone or placebo for 3 wk. TG(mRen2)27 rats displayed increases in systolic blood pressure and plasma aldosterone levels as well as impairments in left ventricular diastolic relaxation without changes in systolic function on cine MRI. TG(mRen2)27 hearts also displayed hypertrophy (left ventricular weight, cardiomyoctye hypertrophy, and septal wall thickness) as well as fibrosis (interstitial and perivascular). There were increases in oxidative stress in TG(mRen2)27 hearts, as evidenced by increases in NADPH oxidase activity and subunits as well as ROS formation. Low-dose spironolactone had no effect on systolic blood pressure but improved diastolic dysfunction comparable to a conventional dose. Both doses of spironolactone caused comparable reductions in ROS/3-nitrotryosine immunostaining and perivascular and interstitial fibrosis. These data support the notion mineralocorticoid receptor blockade improves diastolic dysfunction through improvements in oxidative stress and fibrosis independent of changes in systolic blood pressure.

Influence of partial agonist expression on CD8 T cell responses for non-self antigens (132.35)

Abstract Differences in affinity of TCR for peptide/MHC complex induced by single amino acid substitutions in the peptide dramatically alter recognition by T cell in the periphery. With H60 as an antigenic model, we investigated the influence of transgenic expression of natural H60 antigen (H60N Tg) or of H60 antigen with single amino acid substitution at position 4 to histidine (H60H Tg) on H60H- or H60N-specific CD8 T cell responses, respectively. Immunization of B6 female mice with splenocytes from male H60NTg or H60H Tg mice induced strong CD8 T cell responses against each epitope, H60N or H60H, in CD4 T cell help dependent ways. While the immunization with splenocytes from male H60H Tg induced proliferation of H60-specific CD8 T cell responses in the female H60N Tg mice, CD8 T cell response for H60H induced in female H60N Tg showed significant reduction in the magnitude of H60H-tetramer-binding CD8 T cells at the peak time. And differences in TCR V beta usages of H60H-reactive CD8 T cells were also found between in the female B6 female and female H60N Tg hosts. Our data suggest that expression of proteins with amino acid changes influences the antigen-specific CD8 T cell responses and repertoire of TCRS involved in the responses.

OVEREXPRESSION OF HUMAN DOWN SYNDROME CANDIDATE REGION 1 (DSCR1) GENE IS PROTECTIVE IN STROKE

The Down syndrome candidate region 1 (DSCR1) gene is found on chromosome 21. DSCR1 protein is highly expressed in the brain, and following middle cerebral artery occlusion (MCAO) in mice DSCR1 mRNA and protein increases in the peri‐infarct region. We examined the effect of overexpression of DSCR1 on outcome following stroke. DSCR1 transgenic (Tg) mice were produced by the overexpression of the human DSCR1 gene, only in cells that normally express DSCR1, on a C57Bl6/J X CBA background. Cerebral ischemia was induced by MCAO for 0.5 h followed by reperfusion for 23.5 h (ischemia‐reperfusion; I‐R) in 8–14 week old male DSCR1 Tg (n=14) and wild‐type (Wt; n=9) mice. After 24 h, neurological impairment was assessed (neurological score and hanging wire test). Brain infarct and edema volume were then measured in thionin‐stained coronal sections. After I‐R, Tg mice had less neurological impairment than Wt, with a lower neurological score (2.4±0.3 vs 3.9±0.1; P&lt;0.05) and a longer hanging‐wire time (38±5 vs 9±3 s; P&lt;0.01). After I‐R, Tg mice had a significantly smaller subcortical infarct volume than Wt mice (15±2 vs 32±5 mm3; P&lt;0.01). In addition, total infarct volume tended to be smaller in Tg than Wt mice (26±5 vs. 36±6 mm3; P=0.26). Furthermore, edema volume was smaller in Tg than Wt mice (17±3 vs 31±6 mm3; P&lt;0.05). Thus, overexpression of DSCR1 improves outcome following stroke.

Overexpression of secreted frizzled-related protein 1 inhibits bone formation and attenuates parathyroid hormone bone anabolic effects.

Secreted frizzled-related protein 1 (sFRP1) is an antagonist of Wnt signaling, an important pathway in maintaining bone homeostasis. In this study we evaluated the skeletal phenotype of mice overexpressing sFRP1 (sFRP1 Tg) and the interaction of parathyroid hormone (PTH) treatment and sFRP1 (over)expression. Bone mass and microarchitecture were measured by micro-computed tomography (µCT). Osteoblastic and osteoclastic cell maturation and function were assessed in primary bone marrow cell cultures. Bone turnover was assessed by biochemical markers and dynamic bone histomorphometry. Real-time PCR was used to monitor the expression of several genes that regulate osteoblast maturation and function in whole bone. We found that trabecular bone mass measurements in distal femurs and lumbar vertebral bodies were 22% and 51% lower in female and 9% and 33% lower in male sFRP1 Tg mice, respectively, compared with wild-type (WT) controls at 3 months of age. Genes associated with osteoblast maturation and function, serum bone formation markers, and surface based bone formation were significantly decreased in sFRP1 Tg mice of both sexes. Bone resorption was similar between sFRP1 Tg and WT females and was higher in sFRP1 Tg male mice. Treatment with hPTH(1-34) (40 µg/kg/d) for 2 weeks increased trabecular bone volume in WT mice (females: +30% to 50%; males: +35% to 150%) compared with sFRP1 Tg mice (females: +5%; males: +18% to 54%). Percentage increases in bone formation also were lower in PTH-treated sFRP1 Tg mice compared with PTH-treated WT mice. In conclusion, overexpression of sFRP1 inhibited bone formation as well as attenuated PTH anabolic action on bone. The gender differences in the bone phenotype of the sFRP1 Tg animal warrants further investigation. © 2010 American Society for Bone and Mineral Research

Monitoring of Urinary L-Type Fatty Acid-Binding Protein Predicts Histological Severity of Acute Kidney Injury

The present study aimed to evaluate whether levels of urinary L-type fatty acid-binding protein (L-FABP) could be used to monitor histological injury in acute kidney injury (AKI) induced by cis-platinum (CP) injection and ischemia reperfusion (IR). Different degrees of AKI severity were induced by several renal insults (CP dose and ischemia time) in human L-FABP transgenic mice. Renal histological injury scores increased with both CP dose and ischemic time. In CP-induced AKI, urinary L-FABP levels increased exponentially even in the lowest dose group as early as 2 hours, whereas blood urea nitrogen (BUN) levels increased at 48 hours. In IR-induced AKI, BUN levels increased only in the 30-minute ischemia group 24 hours after reperfusion; however, urinary L-FABP levels increased more than 100-fold, even in the 5-minute ischemia group after 1 hour. In both AKI models, urinary L-FABP levels showed a better correlation with final histological injury scores and glomerular filtration rates measured by fluorescein isothiocyanate-labeled inulin injection than with levels of BUN and urinary N-acetyl-D-glucosaminidase, especially at earlier time points. Receiver operating characteristic curve analysis demonstrated that urinary L-FABP was superior to other biomarkers for the detection of significant histological injuries and functional declines. In conclusion, urinary L-FABP levels are better suited to allow the accurate and earlier detection of both histological and functional insults in ischemic and nephrotoxin-induced AKI compared with conventional renal markers.

Astroglial-NF-kB is a critical regulator of learning and memory and hippocampal neurogenesis in female mice

Event Abstract Back to Event Astroglial-NF-kB is a critical regulator of learning and memory and hippocampal neurogenesis in female mice John Bethea1*, Valerie Bracchi-Ricard1, Giorgia Quadrato1, 2, Anna Dellarole1, 2 and Mariagrazia Grilli2 1 University of Miami, United States 2 University of Piemonte Orientale, Italy We previously investigated the role of astroglial-NF-kB in synaptic plasticity and learning and memory using transgenic mice overexpressing a dominant negative form of IkBa in astrocytes (GFAP-IkBa-dn). We found that female transgenic mice (TG), but not males, have robust deficits in hippocampal and extra-hippocampal-dependent learning and memory. These findings indicate that astroglial NF-kB is an important regulator of learning/memory. These results suggest that neurogenesis may be affected in our female mice.Active neurogenesis continues in the hippocampus throughout adulthood, due to the presence of progenitor cells localized in the subgranular zone of the dentate gyrus (DG). In the hippocampus new neurons become part of an integrated network that plays an important role in learning and memory. Since GFAP is expressed by both putative stem cells and astrocytes in the neurogenic niches, we investigated the contribution of the NF-kB family of transcription factors in adult hippocampal neurogenesis by studying proliferation, survival and differentiation of hippocampal precursor cells in male and female TG mice. Herein, we demonstrate that there are no differences in the proliferation of neuronal stem/progenitor cells in male and female wild type (WT) and TG. The survival and differentiation of neuronal stem/progenitor cells in male TG was also unchanged compared to male WT mice. However, there was a significant reduction in the survival and differentiation of neuronal stem/progenitor cells in female TG mice compared to WT female controls. These results may help explain our sex specific deficits in learning and memory. Since deficits in neuronal stem cells and learning and memory may also be associated with major depressive disorders and stress, which women are reported to suffer from 2-3 times more frequently than men these results may link astroglial-NF-kB to mechanisms underlying major depressive disorders and other sex specific disorders in women. Conference: 41st European Brain and Behaviour Society Meeting, Rhodes Island, Greece, 13 Sep - 18 Sep, 2009. Presentation Type: Oral Presentation Topic: Symposia lectures Citation: Bethea J, Bracchi-Ricard V, Quadrato G, Dellarole A and Grilli M (2009). Astroglial-NF-kB is a critical regulator of learning and memory and hippocampal neurogenesis in female mice. Conference Abstract: 41st European Brain and Behaviour Society Meeting. doi: 10.3389/conf.neuro.08.2009.09.013 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Jun 2009; Published Online: 04 Jun 2009. * Correspondence: John Bethea, University of Miami, Miami, United States, jbethea@miami.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers John Bethea Valerie Bracchi-Ricard Giorgia Quadrato Anna Dellarole Mariagrazia Grilli Google John Bethea Valerie Bracchi-Ricard Giorgia Quadrato Anna Dellarole Mariagrazia Grilli Google Scholar John Bethea Valerie Bracchi-Ricard Giorgia Quadrato Anna Dellarole Mariagrazia Grilli PubMed John Bethea Valerie Bracchi-Ricard Giorgia Quadrato Anna Dellarole Mariagrazia Grilli Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

β-Amyloid Deposition and Functional Impairment in the Retina of the APPswe/PS1ΔE9 Transgenic Mouse Model of Alzheimer’s Disease

To determine whether beta-amyloid (Abeta) deposition affects the structure and function of the retina of the APPswe/PS1DeltaE9 transgenic (tg) mouse model of Alzheimer's disease. Retinas from 12- to 19-month old APPswe/PS1DeltaE9 tg and age-matched non-transgenic (ntg) littermates were single or double stained with thioflavine-S and antibodies against Abeta, glial fibrillar acidic protein (GFAP), microglial marker F4/80, choline acetyltransferase (ChAT), and syntaxin 1. Quantification of thioflavine-S positive plaques and retinal layer thickness was analyzed semi-quantitatively, whereas microglial cell size and levels of F4/80 immunoreactivity were evaluated using a densitometry program. Scotopic electroretinogram (ERG) recording was used to investigate retinal physiology in these mice. Thioflavine-S positive plaques appeared at 12 months in the retinas of APPswe/PS1DeltaE9 tg mice with the majority of plaques in the outer and inner plexiform layers. Plaques were embedded in the inner plexiform layer strata displaying syntaxin 1 and ChAT. The number and size of the plaques in the retina increased with age. Plaques appeared earlier and in greater numbers in females than in male tg littermate mice. Microglial activity was significantly increased in the retinas of APPswe/PS1DeltaE9 tg mice. Although we did not detect neuronal degeneration in the retina, ERG recordings revealed a significant reduction in the amplitudes of a- and b-waves in aged APPswe/PS1DeltaE9 tg compared to ntg littermates. The present findings suggest that Abeta deposition disrupts retinal structure and may contribute to the visual deficits seen in aged APPswe/PS1DeltaE9 tg mice. Whether Abeta is involved in other forms of age-related retinal dysfunction is unclear.

P2-299: Oral administration of an apolipoprotein A-I–mimetic peptide improves cognitive function and reduces amyloid burden in a mouse model of Alzheimer disease

Recent evidences indicate that inflammatory mechanisms represent a component that may significantly contribute to the progression of Alzheimer's disease (AD). Apo A-I mimetic peptide D-4F has been shown to inhibit atherosclerotic lesion formation and in presence of statin, even regresses already existing lesion. Oral administration of D-4F has also been shown to improve cognitive function and decreases brain arteriole inflammation in LDL receptor null mice on Western diet. Since this peptide is in phase II clinical trials for atheroscerosis prevention, we undertook a study to evaluate the efficacy of oral D-4F in presence of pravastatin on the improvement of cognitive performance and inhibition of amyloid β plaque burden in a mouse model of AD. 3 groups of 4 month old male APPswe-PS1ΔE9 Tg mice were used. The first group received D-4F (200μg/ml) + pravastatin (10μg/ml) in drinking water. The second group received a control peptide scrambled D-4F (Sc-D-4F, 200μg/ml) and pravastatin (10μg/ml) and the third group did not receive any drugs. After 3 months of treatment the mice were tested for their ability for spatial learning and retention using Morris Water Maze test. Amyloid burden occupied in the hippocampi was analysed by immunohistochemistry and inflammatory markers in the brain were measured by ELISA. Mice treated with D-4F +statin for 3 months showed a significant improvement in their spatial memory and retention (p< 0.01) compared to the other two groups. In control and Sc-D-4F+statin treated mice the hippocampus area occupied by amyloid plaque was 4.2±0.5% and 3.8±0.6% respectively, whereas in D-4F+statin treated mice the amyloid burden in hippocampus decreased significantly (1.6±0.2%, p< 0.001 vs control and p< 0.01 vs Sc-D-4F+statin group). Brain cytokine levels such as TNF–α and IL-1β levels were also reduced in D-4F administered group compared to the other two groups. In a mouse model of AD, D-4F+statin inhibits amyloid deposition in the hippocampus. Along with inhibition of amyloid plaque, the peptide also improves the hippocampal dependent spatial memory and retention. We also observed lower brain cytokine levels in the D-4F+ statin treated group. This can therefore be a potential therapy for AD.

Increased thermoregulation in cold-exposed transgenic mice overexpressing lipoprotein lipase in skeletal muscle: an avian phenotype?

LPL is an enzyme involved in the breakdown and uptake of lipoprotein triglycerides. In the present study, we examined how the transgenic (Tg) overexpression of human LPL in mouse skeletal muscle affected tolerance to cold temperatures, cold-induced thermogenesis, and fuel utilization during this response. Tg mice and their nontransgenic controls were placed in an environmental chamber and housed in metabolic chambers that monitored oxygen consumption and carbon dioxide production with calorimetry. When exposed to 4 degrees C, an attenuation in the decline in body temperature in Tg mice was accompanied by an increased metabolic rate (15%; P < 0.001) and a reduction in respiratory quotient (P < 0.05). Activity levels, the expression of uncoupling proteins in brown fat and muscle, and lean mass failed to explain the enhanced cold tolerance and thermogenesis in Tg mice. The more oxidative type IIa fibers were favored over the more glycolytic type IIb fibers (P < 0.001) in the gastrocnemius and quadriceps muscles of Tg mice. These data suggest that Tg overexpression of LPL in skeletal muscle increases cold tolerance by enhancing the capacity for fat oxidation, producing an avian-like phenotype in which skeletal muscle contributes significantly to the thermogenic response to cold temperatures.