Development and validation of algorithms for the detection of statin myopathy signals from electronic medical records

The purpose of this study was to develop and validate sensitive algorithms to detect hospitalized statin-induced myopathy (SIM) cases from electronic medical records (EMRs). We developed four algorithms on a training set of 31,211 patient records from a large tertiary hospital. We determined the performance of these algorithms against manually curated records. The best algorithm used a combination of elevated creatine kinase (>4× the upper limit of normal (ULN)), discharge summary, diagnosis, and absence of statin in discharge medications. This algorithm achieved a positive predictive value of 52-71% and a sensitivity of 72-78% on two validation sets of >30,000 records each. Using this algorithm, the incidence of SIM was estimated at 0.18%. This algorithm captured three times more rhabdomyolysis cases than spontaneous reports (95% vs. 30% of manually curated gold standard cases). Our results show the potential power of utilizing data and text mining of EMRs to enhance pharmacovigilance activities.

Pial Collateral Reactivity During Hypertension and Aging: Understanding the Function of Collaterals for Stroke Therapy

Supplemental Digital Content is available in the text.

Background and Purpose—

We investigated vasoactive properties of leptomeningeal arterioles (LMAs) under normotensive conditions and during hypertension and aging that are known to have poor collateral flow and little salvageable tissue.

Methods—

LMAs, identified as distal anastomotic arterioles connecting middle and anterior cerebral arteries, were studied isolated and pressurized from young (18 weeks) or aged (48 weeks) normotensive Wistar Kyoto (WKY18, n=14; WKY48, n=6) rats and spontaneously hypertensive rats (SHR18, n=16; SHR48, n=6). Myogenic tone and vasoactive responses to pressure as well as endothelial function and ion channel activity were measured.

Results—

LMAs from WKY18 had little myogenic tone at 40 mm Hg (8±3%) that increased in aged WKY48 (30±6%). However, LMAs from both WKY groups dilated to increased pressure and demonstrated little myogenic reactivity, a response that would be conducive to collateral flow. In contrast, LMAs from both SHR18 and SHR48 displayed considerable myogenic tone (56±8% and 43±7%; P<0.01 versus WKY) and constricted to increased pressure. LMAs from both WKY and SHR groups had similar basal endothelial nitric oxide and IK channel activity that opposed tone. However, dilation to sodium nitroprusside, diltiazem and 15 mmol/L KCl was impaired in LMAs from SHR18.

Conclusions—

This study shows for the first time that LMAs from young and aged SHR are vasoconstricted and have impaired vasodilatory responses that may contribute to greater perfusion deficit and little penumbral tissue. These results also suggest that therapeutic opening of pial collaterals is possible during middle cerebral artery occlusion to create penumbral tissue and prevent infarct expansion.

Roles of Caveolin-1 in Angiotensin II-Induced Hypertrophy and Inward Remodeling of Cerebral Pial Arterioles

Angiotensin II (Ang II) is a major determinant of inward remodeling and hypertrophy in pial arterioles that may have an important role in stroke during chronic hypertension. Previously, we found that epidermal growth factor receptor is critical in Ang II-mediated hypertrophy that may involve caveolin-1 (Cav-1). In this study, we examined the effects of Cav-1 and matrix metalloproteinase-9 (MMP9) on Ang II-mediated structural changes in pial arterioles. Cav-1-deficient (Cav-1(-/-)), MMP9-deficient (MMP9(-/-)), and wild-type mice were infused with either Ang II (1000 ng/kg per minute) or saline via osmotic minipumps for 28 days (n=6-8 per group). Systolic arterial pressure was measured by a tail-cuff method. Pressure and diameter of pial arterioles were measured through an open cranial window in anesthetized mice. Cross-sectional area of the wall was determined histologically in pressurized fixed pial arterioles. Expression of Cav-1, MMP9, phosphorylated epidermal growth factor receptor, and Akt was determined by Western blotting and immunohistochemistry. Deficiency of Cav-1 or MMP9 did not affect Ang II-induced hypertension. Ang II increased the expression of Cav-1, phosphorylated epidermal growth factor receptor, and Akt in wild-type mice, which was attenuated in Cav-1(-/-) mice. Ang II-induced hypertrophy, inward remodeling, and increased MMP9 expression in pial arterioles were prevented in Cav-1(-/-) mice. Ang II-mediated increases in MMP9 expression and inward remodeling, but not hypertrophy, were prevented in MMP9(-/-) mice. In conclusion, Cav-1 is essential in Ang II-mediated inward remodeling and hypertrophy in pial arterioles. Cav-1-induced MMP9 is exclusively involved in inward remodeling, not hypertrophy. Further studies are needed to determine the role of Akt in Ang II-mediated hypertrophy.

Abstract 223: Leptomeningeal Arteriole Vasoconstriction during Hypertension: Targeting Pial Collaterals in Stroke Treatment

Introduction: Collateral perfusion via leptomeningeal arterioles (LMAs) between middle and anterior cerebral artery (MCA/ACA) territories sustains the penumbra during MCA occlusion (MCAO) and is a key variable in stroke outcome. Hypertension is associated with poor stroke outcome, little penumbral tissue and larger infarctions. Here, we investigated the vasoactive properties of isolated and pressurized LMAs from normotensive and hypertensive animals as a contributor to poor collateral flow.

Hypothesis: Compared to normotensive animals, LMAs from hypertensive animals are vasoconstricted that limits collateral perfusion and penumbral tissue.

Methods: LMAs between MCA and ACA distal branches were dissected from 18 wk old male normotensive Wistar Kyoto (WKY, n=14) and spontaneously hypertensive rats (SHR; n=16), mounted on glass cannulas and studied pressurized.

Results: LMAs from WKY had little basal tone and responded passively to increased pressure from 5 to 80 mmHg. In contrast, LMAs from SHR had considerable tone and responded to pressure with vasoconstriction (Figure 1). Dilatory responses were also diminished in LMAs from SHR vs. WKY, including to the voltage operated calcium channel inhibitor diltiazem (63±6% vs. 88±2% at 10 -5 M; p<0.01), the NO donor sodium nitroprusside (23±6% vs. 74±6% at 10 -5 M; p<0.01), and to 15mM KCl that activates inward rectifier K + channels (-5±45% vs. 78±10%; p<0.01). Structurally, passive diameters of LMAs from SHR were smaller but not significantly different from WKY, suggesting therapeutic opening of collaterals may be possible.

Conclusions: The relatively passive nature of LMAs from WKY would be conducive to retrograde flow during MCAO whereas the vasoconstrictive response of LMAs from SHR could limit collateral perfusion. Therapies that alleviate LMA vasoconstriction may help sustain penumbral flow and extend the time for treatment in those patients that have poor collaterals.

Randomized phase II study of axitinib versus placebo plus best supportive care in second-line treatment of advanced hepatocellular carcinoma

BACKGROUND

The efficacy and safety of axitinib, a potent and selective vascular endothelial growth factor receptors 1-3 inhibitor, combined with best supportive care (BSC) was evaluated in a global, randomized, placebo-controlled phase II trial in patients with locally advanced or metastatic hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Patients with HCC and Child-Pugh Class A who progressed on or were intolerant to one prior antiangiogenic therapy were stratified by tumour invasion (presence/absence of extrahepatic spread and/or vascular invasion) and region (Asian/non-Asian) and randomized (2:1) to axitinib/BSC (starting dose 5 mg twice-daily) or placebo/BSC. The primary end point was overall survival (OS).

RESULTS

The estimated hazard ratio for OS was 0.907 [95% confidence interval (CI) 0.646-1.274; one-sided stratified P = 0.287] for axitinib/BSC (n = 134) versus placebo/BSC (n = 68), with the median (95% CI) of 12.7 (10.2-14.9) versus 9.7 (5.9-11.8) months, respectively. Results of prespecified subgroup analyses in Asian versus non-Asian patients or presence versus absence of tumour invasion were consistent with the overall population. Improvements favouring axitinib/BSC (P < 0.01) were observed in secondary efficacy end point analyses [progression-free survival (PFS), time to tumour progression (TTP), and clinical benefit rate (CBR)], and were retained among Asian patients in the prespecified subgroup analyses. Overall response rate did not differ significantly between treatments and patient-reported outcomes favoured placebo/BSC. Most common all-causality adverse events with axitinib/BSC were diarrhoea (54%), hypertension (54%), and decreased appetite (47%). Baseline serum analyses identified potential new prognostic (interleukin-6, E-selectin, interleukin-8, angiopoietin-2, migration inhibitory factor, and c-MET) or predictive (E-selectin and stromal-derived factor-1) factors for survival.

CONCLUSIONS

Axitinib/BSC did not improve OS over placebo/BSC in the overall population or in stratification subgroups. However, axitinib/BSC resulted in significantly longer PFS and TTP and higher CBR, with acceptable toxicity in patients with advanced HCC.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01210495.

Effect of hypertension and carotid occlusion on brain parenchymal arteriole structure and reactivity

We studied the effect of hypertension and chronic hypoperfusion on brain parenchymal arteriole (PA) structure and function. PAs were studied isolated and pressurized from 18-wk-old Wistar-Kyoto (WKY18; n = 8) and spontaneously hypertensive stroke prone (SHRSP18; n = 8) and 5-wk-old prehypertensive (SHRSP5; n = 8) rats. In separate groups, unilateral common carotid artery occlusion (UCCAo) was performed for 4 wk to cause chronic hypoperfusion in 18-wk-old WKY (WKY18-CH; n = 8) and SHRSP (SHRSP18-CH; n = 8). UCCAo caused PAs to have significantly diminished myogenic tone (31 ± 3 vs. 14 ± 6% at 60 mmHg; P < 0.05) and reactivity to pressure from WKY18-CH vs. WKY18 animals. The effect of UCCAo was limited to normotensive animals, as there was little effect of chronic hypoperfusion on vascular reactivity or percent tone in PAs from SHRSP18 vs. SHRSP18-CH animals (53 ± 4 vs. 41 ± 3%; P > 0.05). However, PAs from SHRSP18 and SHRSP5 animals had significantly greater tone compared with WKY18, suggesting an effect of strain and not hypertension per se on PA vasoconstriction. Structurally, PAs from SHRSP18 and SHRSP5 animals had similar sized lumen diameters, but increased wall thickness and distensibility compared with WKY18. Interestingly, chronic hypoperfusion did not affect the structure of PAs from either WKY18-CH or SHRSP18-CH animals. Thus PAs responded to UCCAo with active vasodilation, but not structural remodeling, an effect that was absent in SHRSP. The increased tone of PAs from SHRSP animals, combined with lack of response to chronic hypoperfusion, may contribute to the propensity for ischemic lesions and increased perfusion deficit during hypertension.

Epidermal growth factor receptor is critical for angiotensin II-mediated hypertrophy in cerebral arterioles

Angiotensin II (Ang II) is a major determinant of vascular remodeling in the cerebral circulation during chronic hypertension, which is an important risk factor for stroke. We examined the molecular mechanism of Ang II-mediated cerebrovascular remodeling that involves the epidermal growth factor receptor (EGFR) pathway. Mutant EGFR mice (waved-2), their heterozygous control (wild-type [WT]), and C57BL/6J mice were infused with Ang II (1000 ng kg(-1) min(-1)) or saline via osmotic minipumps for 28 days (n=8 per group). Eight of the Ang II-infused C57BL/6J mice were cotreated with AG1478 (12 mg/kg per day, IP), a specific EGFR tyrosine kinase inhibitor. Systolic arterial pressure was measured by a tail-cuff method. Pressure and diameter of cerebral arterioles were measured through an open cranial window in anesthetized mice. Cross-sectional area of the wall was determined in pressurized fixed cerebral arterioles. Expression of phosphorylated EGFR (p-EGFR), caveolin-1 (Cav-1), and c-Src was determined by western blotting and immunohistochemistry. Mutation of EGFR or AG1478 treatment did not affect Ang II-induced hypertension. Ang II increased the expression of p-EGFR in WT mice, confirming the activation of EGFR. Ang II induced hypertrophy and inward remodeling of cerebral arterioles in WT mice. Hypertrophy, but not remodeling, was prevented in waved-2 and AG1478-treated C57BL/6J mice. Ang II increased p-EGFR, Cav-1, and c-Src expression in WT but not in waved-2 or AG1478-treated C57BL/6J mice. These results suggest that Ang II-induced hypertrophy in cerebral arterioles involves EGFR-dependent signaling and may include Cav-1 and nonreceptor tyrosine kinase c-Src. This signaling pathway seems to be limited to Ang II-induced hypertrophy, but not inward remodeling, and is independent of blood pressure.

Postischemic reperfusion causes smooth muscle calcium sensitization and vasoconstriction of parenchymal arterioles

BACKGROUND AND PURPOSE

Parenchymal arterioles (PAs) are high-resistance vessels in the brain that connect pial vessels to the microcirculation. We previously showed that PAs have increased vasoconstriction after ischemia and reperfusion that could increase perfusion deficit. Here, we investigated underlying mechanisms by which early postischemic reperfusion causes increased vasoconstriction of PAs.

METHODS

Isolated and pressurized PAs from within the middle cerebral artery territory were studied in male Wistar rats that were either nonischemic control (n=34) or after exposure to transient middle cerebral artery occlusion (MCAO) by filament occlusion for 2 hours with 30 minutes of reperfusion (MCAO; n=38). The relationships among pressure-induced tone, smooth muscle calcium (using Fura 2), and membrane potential were determined. Sensitivity of the contractile apparatus to calcium was measured in permeabilized arterioles using Staphylococcus aureus α-toxin. Reactivity to inhibition of transient receptor potential melastanin receptor type 4 (9-phenanthrol), Rho kinase (Y27632), and protein kinase C (Gö6976) was also measured.

RESULTS

After MCAO, PAs had increased myogenic tone compared with controls (47±2% versus 35±2% at 40 mm Hg; P<0.01), without an increase in smooth muscle calcium (177±21 versus 201±16 nmol/L; P>0.05) or membrane depolarization (-38±4 versus -36±1 mV; P>0.05). In α-toxin-permeabilized vessels, MCAO caused increased sensitivity of the contractile apparatus to calcium. MCAO did not affect dilation to transient receptor potential melastanin receptor type 4 or protein kinase C inhibition but diminished dilation to Rho kinase inhibition.

CONCLUSIONS

The increased vasoconstriction of PAs during early postischemic reperfusion seems to be due to calcium sensitization of smooth muscle and could contribute to infarct expansion and limit neuroprotective agents from reaching their target tissue.

Efficacy and toxicity of intensity-modulated radiation therapy for prostate cancer in Chinese patients

OBJECTIVE

To report the treatment efficacy and toxicity profile of intensitymodulated radiation therapy in Chinese patients with clinically localised prostate cancer.

DESIGN

Historical cohort study.

SETTING

Oncology unit in a university teaching hospital in Hong Kong.

PATIENTS

Patients with clinically localised prostate cancer undergoing intensity-modulated radiation therapy in our institution between May 2001 and November 2009 were reviewed.

MAIN OUTCOME MEASURES

The 5-year biochemical failure–free survival, 5-year overall survival, as well as acute/late gastro-intestinal toxicities and genito-urinary toxicities.

RESULTS

A total of 182 patients were treated with prostate intensitymodulated radiation therapy with or without whole-pelvic radiotherapy. The median follow-up was 44 months. The median patient age was 72 years. Overall survival of the cohort was 92% after 5 years. The favourable, intermediate, and unfavourable risk category distributions of the National Comprehensive Cancer Network were 21 (12%), 42 (23%), and 119 (65%), respectively. The 5-year actuarial biochemical failure–free survival rates for patients in these categories were 95%, 82%, and 80%, respectively. Multivariate analysis identified early tumour stage, low pre-treatment prostate-specific antigen levels, and the use of adjuvant androgen deprivation as independent prognostic factors for better biochemical failure–free survival. Grade 2 and 3 late gastro-intestinal/genito-urinary toxicities occurred in 8%/3% and 4%/3% of the patients, respectively.

CONCLUSION

Intensity-modulated radiation therapy for prostate cancer is feasible and safe in the Chinese population. These data are consistent with the results of other series in Caucasian populations.

Increased pressure-induced tone in rat parenchymal arterioles vs. middle cerebral arteries: role of ion channels and calcium sensitivity

Brain parenchymal arterioles (PAs) are high-resistance vessels that branch off pial arteries and perfuse the brain parenchyma. PAs are the target of cerebral small vessel disease and have been shown to have greater pressure-induced tone at lower pressures than pial arteries. We investigated mechanisms by which brain PAs have increased myogenic tone compared with middle cerebral arteries (MCAs), focusing on differences in vascular smooth muscle (VSM) calcium and ion channel function. The amount of myogenic tone and VSM calcium was measured using Fura 2 in isolated and pressurized PAs and MCAs. Increases in intraluminal pressure caused larger increases in tone and cytosolic calcium in PAs compared with MCAs. At 50 mmHg, myogenic tone was 37 ± 5% for PAs vs. 6.5 ± 4% for MCAs (P < 0.01), and VSM calcium was 200 ± 20 nmol/l in PAs vs. 104 ± 15 nmol/l in MCAs (P < 0.01). In vessels permeabilized with Staphylococcus aureus α-toxin, PAs were not more sensitive to calcium, suggesting calcium sensitization was not at the level of the contractile apparatus. PAs were 30-fold more sensitive to the voltage-dependent calcium channel (VDCC) inhibitor nifedipine than MCAs (EC50 for PAs was 3.5 ± 0.4 vs. 82.1 ± 2.1 nmol/l for MCAs;P < 0.01); however, electrophysiological properties of the VDCC were not different in VSM. PAs had little to no response to the calcium-activated potassium channel inhibitor iberiotoxin, whereas MCAs constricted ∼15%. Thus increased myogenic tone in PAs appears related to differences in ion channel activity that promotes VSM membrane depolarization but not to a direct sensitization of the contractile apparatus to calcium.

Abstract 133: Inhibition of TRPV4 is Protective of the Brain and Cerebral Circulation During Ischemic Stroke

Background: Transient receptor potential vanilloid 4 (TRPV4) channels are highly calcium permeable channels expressed in brain and cerebral endothelium and are regulated by a diverse array of stimuli including shear stress, cell swelling and second messengers. We hypothesized that inhibition of TRPV4 during postischemic reperfusion would be protective of the brain and cerebral endothelium.

Methods: Transient MCAO was used for all experiments. Infarction (by TTC) was measured in TRPV4 knockout mice (n=3) or C57B mice treated upon reperfusion with the TRPV4 inhibitor HC067047 (1mg/kg; n=7) or vehicle (n=8) after 90 minutes of ischemia with 24 hours of reperfusion. To determine the effect of TRPV4 inhibition on BBB permeability, hyperglycemic male Wistar rats (3 days by STZ) were treated with HC067047 (1mg/kg; n=6) or vehicle (n=6) upon reperfusion after 2 hours of ischemia and edema measured at 2 hours by wet:dry weights. Lastly, basal tone of MCAs isolated from male Wistar rats after 2 hours of ischemia with 2 hours of reperfusion (MCAO, n=7) or sham controls (Sham, n=6) was measured before and after addition of HC067047 (1μM) at 75 mmHg.

Results: Infarct volume was significantly reduced in TRPV4 knockout mice and with HC067047 treatment vs. vehicle (17.8 ± 2.8% for KO, 22.9 ± 2.7% for HC067047 vs. 39.8 ± 3.3% for vehicle; p<0.05). Hyperglycemic stroke caused considerable edema formation the ipsilateral vs. contralateral brain in vehicle-treated rats (81.38 ± 0.21% vs. 78.64 ± 0.12%; p<0.01) that was prevented by treatment with HC067047 (78.58 ± 0.22% vs. 78.24 ± 0.11%;p>0.05). MCAO diminished basal tone of MCAs vs. sham (16.3 ± 3.3 vs. 26.4 ± 2.8%; p<0.05) that was restored by HC067047 (25.9 ± 3.0%; p<0.05). The constriction to HC067047 did not occur in MCA that were denuded of endothelium or from sham animals.

Conclusion: These results suggest that postischemic reperfusion activates TRPV4 in cerebral endothelium to cause dilation and BBB permeability. The decreased infarct size after TRPV4 inhibition suggests that activation of TRPV4 during ischemia contributes to neuronal cell death. Thus, inhibition of TRPV4 may be an effective treatment for acute ischemic stroke.

Inhibition of PPARγ during rat pregnancy causes intrauterine growth restriction and attenuation of uterine vasodilation

Decreased peroxisome proliferator-activated receptor gamma (PPARγ) activity is thought to have a major role in preeclampsia through abnormal placental development. However, the role of PPARγ in adaptation of the uteroplacental vasculature that may lead to placental hypoperfusion and fetal growth restriction during pregnancy is not known. Here, pregnant Sprague-Dawley rats (n = 11/group) were treated during the second half of pregnancy with the PPARγ inhibitor GW9662 (10 mg/kg/day in food) or vehicle. Pregnancy outcome and PPARγ mRNA, vasodilation and structural remodeling were determined in maternal uterine and mesenteric arteries. PPARγ was expressed in uterine vascular tissue of both non-pregnant and pregnant rats with ~2-fold greater expression in radial vs. main uterine arteries. PPARγ mRNA levels were significantly higher in uterine compared to mesenteric arteries. GW9662 treatment during pregnancy did not affect maternal physiology (body weight, glucose, blood pressure), mesenteric artery vasodilation or structural remodeling of uterine and mesenteric vessels. Inhibition of PPARγ for the last 10 days of gestation caused decreased fetal weights on both day 20 and 21 of gestation that was associated with impaired vasodilation of radial uterine arteries in response to acetylcholine and sodium nitroprusside. These results define an essential role of PPARγ in the control of uteroplacental vasodilatory function during pregnancy, an important determinant of blood flow to the placenta and fetus. Strategies that target PPARγ activation in the uterine circulation could have important therapeutic potential in treatment of pregnancies complicated by hypertension, diabetes or preeclampsia.

Deficiency of Nox2 prevents angiotensin II-induced inward remodeling in cerebral arterioles

Angiotensin II is an important determinant of inward remodeling in cerebral arterioles. Many of the vascular effects of angiotensin II are mediated by reactive oxygen species (ROS) generated from homologs of NADPH oxidase with Nox2 predominating in small arteries and arterioles. Therefore, we tested the hypothesis that superoxide generated by Nox2 plays a role in angiotensin II-induced cerebral arteriolar remodeling. We examined Nox2-deficient and wild-type (WT) mice in which a pressor or a non-pressor dose of angiotensin II (1000 or 200 ng/kg/day) or saline was infused for 4 weeks via osmotic minipumps. Systolic arterial pressure was measured by a tail-cuff method. Pressure and diameter of cerebral arterioles were measured through an open cranial window in anesthetized mice. Cross-sectional area (by histology) and superoxide level (by hydroethidine staining) of cerebral arterioles were determined ex vivo. The pressor, but not the non-pressor, dose of angiotensin II significantly increased systolic arterial pressure in both WT and Nox2-deficient mice. Both doses of angiotensin II increased superoxide levels and significantly reduced external diameter in maximally dilated cerebral arterioles in WT mice. Increased superoxide and inward remodeling were prevented in Nox2-deficient mice. Moreover, only the pressor dose of AngII increased cross-sectional area of arteriolar wall in WT mice and was prevented in Nox2-deficient mice. In conclusion, superoxide derived from Nox2-containing NADPH oxidase plays an important role in angiotensin II-mediated inward remodeling in cerebral arterioles. This effect appears to be independent of pressure and different from that of hypertrophy.

Treatment for cerebral small vessel disease: effect of relaxin on the function and structure of cerebral parenchymal arterioles during hypertension

We investigated the effect of hypertension on the function and structure of cerebral parenchymal arterioles (PAs), a major target of cerebral small vessel disease (SVD), and determined whether relaxin is a treatment for SVD during hypertension. PAs were isolated from 18-wk-old female normotensive Wistar-Kyoto (WKY) rats, spontaneous hypertensive rats (SHRs), and SHRs treated with human relaxin 2 for 14 d (4 μg/h; n=8/group) and studied using a pressurized arteriograph system. Hypertension reduced PA inner diameter (58±3 vs. 49±3 μm at 60 mmHg in WKY rats, P<0.05), suggesting inward remodeling that was reversed by relaxin (56±4 μm, P<0.05). Relaxin also increased PA distensibility in SHRs (34±2 vs. 10±2% in SHRs, P<0.05). Relaxin was detected in cerebrospinal fluid (110±30 pg/ml) after systemic administration, suggesting that it crosses the blood-brain barrier (BBB). Relaxin receptors (RXFP1/2) were not detected in cerebral vasculature, but relaxin increased vascular endothelial growth factor (VEGF) and matrix metalloproteinase 2 (MMP-2) expression in brain cortex. Inhibition of VEGF receptor tyrosine kinase (axitinib, 4 mg/kg/d, 14 d) had no effect on increased distensibility with relaxin, but caused outward hypertrophic remodeling of PAs from SHRs. These results suggest that relaxin crosses the BBB and activates MMP-2 in brain cortex, which may interact with PAs to increase distensibility. VEGF appears to be involved in remodeling of PAs, but not relaxin-induced increased distensibility.

Anaemia and type 2 diabetes: implications from a retrospectively studied primary care case series

OBJECTIVES. To identify the prevalence of anaemia in Chinese type 2 diabetic patients managed in a primary care setting and to explore its associations with cardiovascular complications and kidney disease. DESIGN. Retrospective case series study. SETTING. General Out-patient Clinic of Hospital Authority, Hong Kong. PATIENTS. Chinese type 2 diabetic patients who had annual assessments between 1 January 2010 and 31 December 2011 were recruited. Their complete blood picture, serum creatinine, estimated glomerular filtration rate (calculated by Modification of Diet in Renal Disease method), haemoglobin A1c, and urine albumin-creatinine ratio were retrieved. Anaemia was defined as a haemoglobin level of <130 g/L in men and <120 g/L in women (World Health Organization criteria). Student's t test and analysis of variance were used to analyse continuous variables and the Chi squared test for categorical data. Pearson's correlation coefficient and multivariate logistic regression were used to examine associations between haemoglobin level and different variables including age, gender, serum creatinine level, estimated glomerular filtration rate, and urine albumin-creatinine ratio. All statistical tests were two-sided, and a P value of <0.05 was considered significant. RESULTS. Among 6325 Chinese type 2 diabetic patients fulfilling the inclusion criteria, 1441 were found to have anaemia with a period prevalence of 22.8%. The prevalence of anaemia increased significantly with deterioration of renal function. Compared with diabetic patients with normal haemoglobin levels, anaemic diabetic patients had a higher co-morbidity rate for stroke, ischaemic heart disease, hypertension, and chronic kidney disease (P<0.001). Independent predictors for haemoglobin level among diabetic patients were age, gender, serum creatinine level, estimated glomerular filtration rate, haemoglobin A1c, and urine albumin-creatinine ratio (P<0.001). Multivariate analysis showed that male gender, old age, increased serum creatinine level, decreased estimated glomerular filtration rate, elevated urine albumin-creatinine ratio, and co-morbidity with stroke or ischaemic heart disease were associated with greater odds for the presence of anaemia. CONCLUSION. Anaemia is common among Chinese type 2 diabetic patients, particularly those with impaired renal function or established cardiovascular disease. Early detection of anaemia and prompt referral to specialist care for optimal treatment, if associated with severe renal impairment or high-risk proteinuria at the primary care settings, is recommended.

Nox2 deficiency prevents hypertension-induced vascular dysfunction and hypertrophy in cerebral arterioles

Oxidative stress is involved in many hypertension-related vascular diseases in the brain, including stroke and dementia. Thus, we examined the role of genetic deficiency of NADPH oxidase subunit Nox2 in the function and structure of cerebral arterioles during hypertension. Arterial pressure was increased in right-sided cerebral arterioles with transverse aortic banding for 4 weeks in 8-week-old wild-type (WT) and Nox2-deficient (-/y) mice. Mice were given N(G)-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg) or vehicle to drink. We measured the reactivity in cerebral arterioles through open cranial window in anesthetized mice and wall cross-sectional area and superoxide levels ex vivo. Aortic constriction increased systolic and pulse pressures in right-sided carotid arteries in all groups of mice. Ethidium fluorescence showed increased superoxide in right-sided cerebral arterioles in WT, but not in Nox2-/y mice. Dilation to acetylcholine, but not sodium nitroprusside, was reduced, and cross-sectional areas were increased in the right-sided arterioles in WT, but were unchanged in Nox2-/y mice. L-NAME reduced dilation to acetylcholine but did not result in hypertrophy in right-sided arterioles of Nox2-/y  mice. In conclusion, hypertension-induced superoxide production derived from Nox2-containing NADPH oxidase promotes hypertrophy and causes endothelial dysfunction in cerebral arterioles, possibly involving interaction with nitric oxide.

Effect of pregnancy and nitric oxide on the myogenic vasodilation of posterior cerebral arteries and the lower limit of cerebral blood flow autoregulation

Hemorrhage during parturition can lower blood pressure beyond the lower limit of cerebral blood flow (CBF) autoregulation that can cause ischemic brain injury. However, the impact of pregnancy on the lower limit of CBF autoregulation is unknown. We measured myogenic vasodilation, a major contributor of CBF autoregulation, in isolated posterior cerebral arteries (PCAs) from nonpregnant and late-pregnant rats (n = 10/group) while the effect of pregnancy on the lower limit of CBF autoregulation was studied in the posterior cerebral cortex during controlled hemorrhage (n = 8). Pregnancy enhanced myogenic vasodilation in PCA and shifted the lower limit of CBF autoregulation to lower pressures. Inhibition of nitric oxide synthase (NOS) prevented the enhanced myogenic vasodilation during pregnancy but did not affect the lower limit of CBF autoregulation. The shift in the autoregulatory curve to lower pressures during pregnancy is likely protective of ischemic injury during hemorrhage and appears to be independent of NOS.

Abstract WP440: Relaxin Selectively Affects Brain Parenchymal Arteriolar Structure during Hypertension

Background: Cerebral small vessel disease (SVD) is a common hypertension-related vasculopathy of the penetrating arterioles (PA) that causes lacunar stroke, white matter lesions and vascular dementia. We investigated the effect of chronic hypertension on PA structure and if treatment with relaxin, a hormone with cardioprotective effects previously shown to promote selective outward remodeling of PA in normotensive animals, could reverse these effects.

Methods: Female SHR rats (n=7-8/group) were treated in vivo with relaxin (4μg/hr) or vehicle for 2 weeks and studied at 18 weeks of age. Aged-matched WKY rats were used as controls. Middle cerebral arteries (MCA) and PA from the same animals were isolated and studied under pressurized conditions in zero calcium buffer to obtain structural measurements. Blood pressures were measured using tail cuff after 3 days of training.

Results: PA inner and outer diameters were smaller in SHR vs. WKY: at 100 mmHg PA inner and outer diameters were 59 ± 3 and 72 ± 3 μm for WKY vs. 50 ± 3 and 63 ± 3 μm for SHR (p<0.01). Relaxin treatment of SHR reversed this rarefaction such that inner and outer diameters were similar to WKY: 58 ± 4 and 69 ± 4 μm (p<0.01 vs. SHR; Figure). The increase in PA size with relaxin treatment was related to a large increase in distensibility (Figure). Percent distensibility of PA for WKY, SHR and SHR+relaxin was: 18 ± 3%, 13 ± 2% and 40 ± 4% (p<0.01). Relaxin treatment had no effect on MCA in SHR that were smaller than WKY: MCA inner and outer diameters were 258 ± 4 and 285 ± 5 μm in WKY, 228 ± 5 and 260 ± 5 μm in SHR and 225 ± 4 and 256 ± 4 μm in SHR+relaxin (p>0.05). Relaxin also did not lower blood pressures that were higher in SHR: MAP for WKY, SHR and SHR+relaxin was: 94 ± 3, 138 ± 2 and 144 ± 5 mmHg (p<0.01 vs. WKY).

Conclusion: These results suggest that relaxin may be an effective treatment for hypertension-induced rarefaction and increased stiffness of PA that underlies SVD in the brain.

Determination of PPARγ activity in adipose tissue and spleen

Peroxisome proliferator-activated receptor-gamma (PPARγ) is a nuclear transcription factor that regulates many genes and is involved in extensive biological functions. Accurately determining PPARγ activity in various tissues is important to understanding mechanisms of human physiology and pathophysiology. Thus, we evaluated a PPARγ DNA binding immunoassay using nuclear extracts of spleen and adipose tissue from rats treated with rosiglitazone (20 mg/kg in food, seven days, n = 6) or vehicle (n = 6) and compared the results to mRNA expression of PPARγ target genes--a well-established method to investigate PPARγ activity. In adipose tissue, the PPARγ immunoassay showed that rosiglitazone did not change PPARγ binding, but qPCR analysis showed that expression of two PPARγ target genes, CD36 and liver X receptor-α, were significantly increased. In spleen, the PPARγ immunoassay showed that rosiglitazone decreased PPARγ binding, but qPCR analysis showed no significant change. The different results obtained between PPARγ binding immunoassay and target gene expression suggest that PPARγ immunoassays may not be suitable when used with fresh homogenates of spleen and adipose tissue. Validation of the assay with each individual tissue is recommended.

Effect of pregnancy on autoregulation of cerebral blood flow in anterior versus posterior cerebrum

Severe preeclampsia and eclampsia are associated with brain edema that forms preferentially in the posterior cerebral cortex possibly because of decreased sympathetic innervation of posterior cerebral arteries and less effective autoregulation during acute hypertension. In the present study, we examined the effect of pregnancy on the effectiveness of cerebral blood flow autoregulation using laser Doppler flowmetry and edema formation by wet:dry weight in acute hypertension induced by phenylephrine infusion in the anterior and posterior cerebrum from nonpregnant (n=8) and late-pregnant (n=6) Sprague-Dawley rats. In addition, we compared the effect of pregnancy on sympathetic innervation by tyrosine hydroxylase staining of posterior and middle cerebral arteries (n=5-6 per group) and endothelial and neuronal NO synthase expression using quantitative PCR (n=3 per group). In nonpregnant animals, there was no difference in autoregulation between the anterior and posterior cerebrum. However, in late-pregnant animals, the threshold of cerebral blood flow autoregulation was shifted to lower pressures in the posterior cerebrum, which was associated with increased neuronal NO synthase expression in the posterior cerebral cortex versus anterior. Compared with the nonpregnant state, pregnancy increased the threshold of autoregulation in both brain regions that was related to decreased expression of endothelial NO synthase. Lastly, acute hypertension during pregnancy caused greater edema formation in both brain cortices that was not attributed to changes in sympathetic innervation. These findings suggest that, although pregnancy shifted the cerebral blood flow autoregulatory curve to higher pressures in both the anterior and posterior cortices, it did not protect from edema during acute hypertension.

A phase II study of concurrent cetuximab-cisplatin and intensity-modulated radiotherapy in locoregionally advanced nasopharyngeal carcinoma

BACKGROUND

Based on our previous work on the clinical activity of cetuximab in recurrent nasopharyngeal carcinoma (NPC), we evaluated the feasibility of adding cetuximab to concurrent cisplatin and intensity-modulated radiotherapy (IMRT) in locoregionally advanced NPC.

PATIENTS AND METHODS

Patients with American Joint Committee on Cancer stage III-IVB NPC were given an initial dose of cetuximab (400 mg/m(2)) 7-10 days before receiving concurrent IMRT, weekly cisplatin (30 mg/m(2)/week) and cetuximab (250 mg/m(2)/week).

RESULTS

Thirty patients (median age of 45 years) with stage III (67%), IVA (30%) and IVB (3%) nonkeratinizing NPC were enrolled. Grade 3-4 oropharyngeal mucositis occurred in 26 (87%) patients and 10 (33%) patients required short-term nasogastric feeding. Grade 3 radiotherapy-related dermatitis occurred in six patients (20%) and three patients (10%) had grade 3 cetuximab-related acneiform rash. These grade 3-4 skin and mucosal toxic effects were manageable and reversible. At a median follow-up of 31.8 months [95% confidence interval (CI) 26.2-32.1 months], the 2-year progression-free survival was 86.5% (95% CI 74.3% to 98.8%).

CONCLUSIONS

Concurrent administration of cetuximab, weekly cisplatin and IMRT is a feasible strategy against locoregionally advanced NPC. Preliminary survival data compare favorably with historic data and further follow-up is warranted.