Metabolic Responses of Normal Rat Kidneys to a High Salt Intake

In this study, novel methods were developed, which allowed continuous (24/7) measurement of arterial blood pressure and renal blood flow in freely moving rats and the intermittent collection of arterial and renal venous blood to estimate kidney metabolic fluxes of O2 and metabolites. Specifically, the study determined the effects of a high salt (HS; 4.0% NaCl) diet upon whole kidney O2 consumption and arterial and renal venous plasma metabolomic profiles of normal Sprague-Dawley rats. A separate group of rats was studied to determine changes in the cortex and outer medulla tissue metabolomic and mRNAseq profiles before and following the switch from a 0.4% to 4.0% NaCl diet. In addition, targeted mRNA expression analysis of cortical segments was performed. Significant changes in the metabolomic and transcriptomic profiles occurred with feeding of the HS diet. A progressive increase of kidney O2 consumption was found despite a reduction in expression of most of the mRNA encoding enzymes of TCA cycle. A novel finding was the increased expression of glycolysis-related genes in Cx and isolated proximal tubular segments in response to an HS diet, consistent with increased release of pyruvate and lactate from the kidney to the renal venous blood. Data suggests that aerobic glycolysis (eg, Warburg effect) may contribute to energy production under these circumstances. The study provides evidence that kidney metabolism responds to an HS diet enabling enhanced energy production while protecting from oxidative stress and injury. Metabolomic and transcriptomic analysis of kidneys of Sprague-Dawley rats fed a high salt diet.

Metabolic responses of normal rat kidneys to a high salt intake

In the present study, novel methods were developed which allowed continuous (24/7) measurement of blood pressure (BP) and renal blood flow (RBF) in freely moving rats and the intermittent collection of arterial and renal venous blood to estimate kidney metabolic fluxes of O 2 and metabolites. The study determined the effects of a high salt (HS) diet upon whole kidney O 2 consumption and the metabolomic profiles of normal Sprague Dawley (SD) rats. A separate group of rats was studied to determine changes in the cortex (Cx) and outer medulla (OM) tissue metabolomic and mRNAseq profiles before and following the switch from a 0.4% to a 4.0% NaCl diet. Significant changes in the metabolomic and transcriptomic profiles occurred with feeding of the HS diet. A progressive increase of kidney O 2 consumption was found despite a reduction in expression of most of the mRNA encoding enzymes of TCA cycle. Increased glycolysis was evident with the elevation of mRNA expression encoding key glycolytic enzymes and release of pyruvate and lactate from the kidney in the renal venous blood. Glycolytic production of NADH is used in either the production of lactate or oxidized via the malate aspartate shuttle. Aerobic glycolysis (e.g., Warburg-effect) may account for the needed increase in cellular energy. The study provides evidence that kidney metabolism responds to a HS diet enabling enhanced energy production while protecting from oxidate stress and injury.

Psychosocial wellbeing of Berlin school children during the COVID-19 pandemic, June 2020-March 2021

Background

The COVID-19 pandemic and related restrictions have affected the wellbeing of school children worldwide. Specific problems evolving during the pandemic, their extent and duration haveńt been sufficiently explored yet. We aimed at describing school childreńs psychosocial and behavioral parameters and associated factors during the COVID-19 pandemic in Berlin, Germany.

Methods

Our longitudinal study included students from 24 randomly selected Berlin primary and secondary schools, assessing psychosocial wellbeing and behaviors at four time points between June 2020 and March 2021. We analyzed temporal changes in the proportions of anxiety, fear of infection, reduced health-related quality of life (HRQoL), physical activity and social contacts, as well as sociodemographic and economic factors associated with anxiety, fear of infection and HRQoL.

Results

Of initially 384 recruited students, 324 still participated in the fourth study round after nine months. During the observation period, presence of anxiety symptoms increased from 26.2% (96/367) to 34.6% (62/179), and fear of infection from 28.6% (108/377) to 40.6% (73/180). The proportion of children with limited social contacts (<1/week) increased from 16.4% (61/373) to 23.5% (42/179). Low physical activity (<3 times sports/week) was consistent over time. Low HRQoL was observed among 44% (77/174). Factors associated with anxiety were female sex, increasing age, secondary school attendance, lower household income, and presence of adults with anxiety symptoms in the student's household. Fear of infection and low HRQoL were associated with anxiety.

Conclusions

A substantial proportion of school children experienced unfavorable psychosocial conditions during the COVID-19 pandemic in 2020/2021. In particular, students from households with limited social and financial resilience require special attention.

Key messages

Divergent roles of angiotensin II upon the immediate and sustained increases of renal blood flow following unilateral nephrectomy

Although the molecular and functional responses related to renal compensatory hypertrophy after unilateral nephrectomy (UNX) has been well described, many aspects of these events remain unclear. One question is how the remaining kidney senses the absence of the contralateral organ, and another is what the role of the renin-angiotensin system is in these responses. Both acute anesthetized and chronic unanesthetized experiments were performed using the angiotensin II type 1 receptor blocker losartan and the renin inhibitor aliskiren to determine the contribution of the renin-angiotensin system to immediate changes and losartan for chronic changes of renal blood flow (RBF) and the associated hypertrophic events in male Sprague-Dawley rats. Chronic experiments used implanted RBF probes and arterial catheters for continuous data collection, and the glomerular filtration rate was determined by noninvasive transcutaneous FITC-sinistrin measurements. The results of the acute experiments found that RBF increased nearly 25% (4.6 ± 0.5 to 5.6 ± 0.6 mL/min/g kidney wt) during the first 15 min following UNX and that this response was abolished by losartan (6.7 ± 0.7 to 7.0 ± 0.7 mL/min/g kidney wt) or aliskiren (5.8 ± 0.4 to 6.0 ± 0.4 mL/min/g kidney wt) treatment. Thereafter, RBF increased progressively over 7 days, and kidney weight increased by 19% of pre-UNX values. When normalized to kidney weight determined at day 7 after UNX, RBF was not significantly different from pre-UNX levels. Semiquantification of CD31-positive capillaries revealed increases of the glomeruli and peritubular capillaries that paralleled the kidney hypertrophy. None of these chronic changes was inhibited by losartan treatment, indicating that neither the compensatory structural nor the RBF changes were angiotensin II type 1 receptor dependent.NEW & NOTEWORTHY This study found that the immediate increases of renal blood flow (RBF) following unilateral nephrectomy (UNX) are a consequence of reduced angiotensin II type 1 (AT1) receptor stimulation. The continuous monitoring of RBF and intermittent measurement of glomerular filtration rate (GFR) in conscious rats during the 1-wk period of rapid hypertrophy following UNX provided unique insights into the regulation of RBF and GFR when faced with increased metabolic loads. It was found that neither kidney hypertrophy nor the associated increase of capillaries was an AT1-dependent phenomenon.

Hydrogen peroxide (H2O2) mediated activation of mTORC2 increases intracellular Na+ concentration in the renal medullary thick ascending limb of Henle

Hydrogen peroxide (H2O2) production in the renal outer medulla is an important determinant of renal medullary blood flow and blood pressure (BP) salt-sensitivity in Dahl salt-sensitive (SS) rats. The mechanisms and pathways responsible for these actions are poorly understood. Recently, we have discovered that the mTOR complex 2 (mTORC2) plays a critical role in BP salt-sensitivity of SS rats by regulating Na+ homeostasis. PP242, an inhibitor of mTORC1/2 pathways exhibits potent natriuretic actions and completely prevented salt-induced hypertension in SS rats. In the present study, we have found that chronic infusion of H2O2 into the single remaining kidney of Sprague Dawley (SD) rats (3 days) stimulated the functional marker (pAKTSer473/AKT) of mTORC2 activity measured by Western Blot analysis. No changes in mTORC1 activity in OM were observed as determined by pS6Ser235/236/S6. Using fluorescent microscopy and the Na+ sensitive dye Sodium Green, we have shown that H2O2 (100 µM added in the bath) increased intracellular sodium concentration ([Na+]i) in renal medullary thick ascending limbs (mTALs) isolated from SD rats. These responses were almost completely abolished by pretreatment of mTAL with 10 µM PP242, indicating that mTORC1/2 pathways were involved in the H2O2 induced increase of [Na+]i. mTAL cell volume remained unchanged (± 1%) by H2O2 as determined by 3D reconstruction confocal laser scanning microscopy techniques. Consistent with the microscopy data, Western Blot analysis of proteins obtained from freshly isolated mTAL treated with 100 µM H2O2 exhibited increased activity/phosphorylation of AKT (pAKTSer473/AKT) that was inhibited by PP242. This was associated with increased protein activity of the apical membrane cotransporter Na+-K+-2Cl- (NKCC2) and the Na/H exchanger (NHE-3). Na+-K+-ATPase activity was increased as reflected an increase in the ratio of pNa+-K+-ATPaseSer16 to total Na+-K+-ATPase. Overall, the results indicate that H2O2 mediated activation of mTORC2 plays a key role in transducing the observed increases of cytosolic [Na+]i despite associated increases of basolateral pump activity.

Acute neurological care in north-east Germany with telemedicine support (ANNOTeM): protocol of a multi-center, controlled, open-label, two-arm intervention study

Background

Both diagnosis and treatment of neurological emergencies require neurological expertise and are time-sensitive. The lack of fast neurological expertise in regions with underserved infrastructure poses a major barrier for state-of-the-art care of patients with acute neurological diseases and leads to disparity in provision of health care. The main purpose of ANNOTeM (acute neurological care in North East Germany with telemedicine support) is to establish effective and sustainable support structures for evidence based treatments for stroke and other neurological emergencies and to improve outcome for acute neurological diseases in these rural regions.

Methods

A “hub-and-spoke” network structure was implemented connecting three academic neurological centres (“hubs”) and rural hospitals (“spokes”) caring for neurological emergencies. The network structure includes (1) the establishment of a 24/7 telemedicine consultation service, (2) the implementation of standardized operating procedures (SOPs) in the network hospitals, (3) a multiprofessional training scheme, and (4) a quality management program. Data from three major health insurance companies as well as data from the quality management program are being collected and evaluated. Primary outcome is the composite of first time of receiving paid outpatient nursing care, first time of receiving care in a nursing home, or death within 90 days after hospital admission.

Discussion

Beyond stroke only few studies have assessed the effects of telemedically supported networks on diagnosis and outcome of neurological emergencies. ANNOTeM will provide information whether this approach leads to improved outcome. In addition, a health economic analysis will be performed.

Study registration

German Clinical Trials Register DRKS00013067, date of registration: November 16 th, 2017, URL: http://www.drks.de/DRKS00013068

Renal Perfusion Pressure Determines Infiltration of Leukocytes in the Kidney of Rats With Angiotensin II-Induced Hypertension

The present study examined the extent to which leukocyte infiltration into the kidneys in Ang II (angiotensin II)-induced hypertension is determined by elevation of renal perfusion pressure (RPP). Male Sprague-Dawley rats were instrumented with carotid and femoral arterial catheters for continuous monitoring of blood pressure and a femoral venous catheter for infusion. An inflatable aortic occluder cuff placed between the renal arteries with computer-driven servo-controller maintained RPP to the left kidney at control levels during 7 days of intravenous Ang II (50 ng/kg per minute) or vehicle (saline) infusion. Rats were fed a 0.4% NaCl diet throughout the study. Ang II-infused rats exhibited nearly a 50 mm Hg increase of RPP (carotid catheter) to the right kidney while RPP to the left kidney (femoral catheter) was controlled at baseline pressure throughout the study. As determined at the end of the studies by flow cytometry, right kidneys exhibited significantly greater numbers of T cells, B cells, and monocytes/macrophages compared with the servo-controlled left kidneys and compared with vehicle treated rats. No difference was found between Ang II servo-controlled left kidneys and vehicle treated kidneys. Immunostaining found that the density of glomeruli, cortical, and outer medullary capillaries were significantly reduced in the right kidney of Ang II-infused rats compared with servo-controlled left kidney. We conclude that in this model of hypertension the elevation of RPP, not Ang II nor dietary salt, leads to leukocyte infiltration in the kidney and to capillary rarefaction.

NOX4/H2O2/mTORC1 Pathway in Salt-Induced Hypertension and Kidney Injury

We have reported that a high-salt (4.0% NaCl) dietary intake activates mTORC1 and inhibition of this pathway with rapamycin blunts the chronic phase of salt-induced hypertension and renal injury in Dahl salt-sensitive (SS) rats. In SS rats, high-salt intake is known to increase the renal production of H2O2 by NOX4, the most abundant NOX isoform in the kidney, and the global knockout of NOX4 blunts salt-sensitivity in these rats. Here, we explored the hypothesis that elevations of H2O2 by NOX4 in high-salt fed SS rat stimulate mTORC1 for the full development of salt-induced hypertension and renal injury. Our in vitro studies found that H2O2 activates mTORC1 independent of PI3K/AKT and AMPK pathways. To determine the in vivo relevance of NOX4/H2O2/mTORC1 in the salt-induced hypertension, SS-Nox4 knockout (SSNox4-/-) rats were daily administrated with vehicle/rapamycin fed a high-salt diet for 21 days. Rapamycin treatment of SSNox4-/- rats had shown no augmented effect on the salt-induced hypertension nor upon indices of renal injury. Significant reductions of renal T lymphocyte and macrophage together with inhibition of cell proliferation were observed in rapamycin treated rats suggesting a role of mTORC1 independent of NOX4 in the proliferation of immune cell. Given the direct activation of mTORC1 by H2O2 and absence of any further protection from salt-induced hypertension in rapamycin-treated SSNox4-/- rats, we conclude that NOX4-H2O2 is a major upstream activator of mTORC1 that contributes importantly to salt-induced hypertension and renal injury in the SS rat model.

Therapeutic Suppression of mTOR (Mammalian Target of Rapamycin) Signaling Prevents and Reverses Salt-Induced Hypertension and Kidney Injury in Dahl Salt-Sensitive Rats

mTOR (mammalian target of rapamycin) signaling has emerged as a key regulator in a wide range of cellular processes ranging from cell proliferation, immune responses, and electrolyte homeostasis. mTOR consists of 2 distinct protein complexes, mTORC1 (mTOR complex 1) and mTORC2 (mTOR complex 2) with distinct downstream signaling events. mTORC1 has been implicated in pathological conditions, such as cancer and type 2 diabetes mellitus in humans, and inhibition of this pathway with rapamycin has been shown to attenuate salt-induced hypertension in Dahl salt-sensitive rats. Several studies have found that the mTORC2 pathway is involved in the regulation of renal tubular sodium and potassium transport, but its role in hypertension has remained largely unexplored. In the present study, we, therefore, determined the effect of mTORC2 inhibition with compound PP242 on salt-induced hypertension and renal injury in salt-sensitive rats. We found that PP242 not only completely prevented but also reversed salt-induced hypertension and kidney injury in salt-sensitive rats. PP242 exhibited potent natriuretic actions, and chronic administration tended to produce a negative Na⁺ balance even during high-salt feeding. The results indicate that mTORC2 and the related downstream associated pathways play an important role in regulation of sodium balance and arterial pressure regulation in salt-sensitive rats. Therapeutic suppression of the mTORC2 pathway represents a novel pathway for the potential treatment of hypertension.

Abstract P111: Renal Perfusion Pressure Determines Renal Leukocyte Infiltration During Angiotensin II-Induced Hypertension in Sprague Dawley Rats

A large body of work demonstrates an important role of renal infiltrating leukocytes in the development of hypertension and end-organ damage. We recently reported that the renal leukocyte infiltration during high salt-induced hypertension in Dahl Salt Sensitive (SS) rats was dependent on the elevated renal perfusion pressure (RPP). Here we performed studies to determine if the observed effects were limited to the Dahl SS rat and to separate out the effect of the high salt diet. We report here that renal leukocyte infiltration during Angiotensin II-induced (AngII) hypertension in rats is mediated by an increased RPP. Male Sprague-Dawley rats (n = 6) were maintained on a 0.4% NaCl diet throughout the study. At 9 weeks of age, rats were instrumented with carotid and femoral arterial catheters for measuring blood pressure (BP), a femoral venous catheter for AngII infusion, and a balloon occluder cuff was placed around the abdominal aorta between the renal arteries. The carotid and the femoral mean arterial pressures were used as surrogates for the RPP of the right and left kidneys respectively. After 7 days of recovery, baseline BP was measured for 3 days, then the rats were infused with AngII (50 ng/kg/min) for 7 days to induce hypertension. A computer-driven servo-control system was used to inflate the aortic cuff to maintain left RPP at baseline levels while right RPP was uncontrolled. Following 7 days of Ang II infusion, kidneys were removed to assess leukocyte infiltration by flow cytometry, and animals were euthanized. Baseline RPP was similar between right and left kidneys (115.6±3.9 vs 110.5±4.3 mmHg respectively). However, following 7 days of AngII infusion, the right RPP was significantly higher than left RPP (164.7±9.9 vs 112.5 ± 4.2 mmHg; respectively p<0.001). Significantly greater numbers of infiltrated leukocytes were found in the right compared to the left kidney (1.00±0.24 vs 0.53±0.10 X10 7 CD45+cells/kidney p=0.04) and assessment of the subsets found greater numbers of T cells (CD3+), B cells (CD45R+) and monocytes/macrophages (CD11b/c+) in the right kidney compared to the servo-controlled left kidney. The findings from these studies strongly support a critical role for RPP in renal leukocyte infiltration during AngII hypertension in rats fed low salt.

High intraoperative inspiratory oxygen fraction and risk of major respiratory complications

Background

High inspiratory oxygen fraction ( FIO2 ) may improve tissue oxygenation but also impair pulmonary function. We aimed to assess whether the use of high intraoperative FIO2 increases the risk of major respiratory complications.

Methods

We studied patients undergoing non-cardiothoracic surgery involving mechanical ventilation in this hospital-based registry study. The cases were divided into five groups based on the median FIO2 between intubation and extubation. The primary outcome was a composite of major respiratory complications (re-intubation, respiratory failure, pulmonary oedema, and pneumonia) developed within 7 days after surgery. Secondary outcomes included 30-day mortality. Several predefined covariates were included in a multivariate logistic regression model.

Results

The primary analysis included 73 922 cases, of whom 3035 (4.1%) developed a major respiratory complication within 7 days of surgery. For patients in the high- and low-oxygen groups, the median FIO2 was 0.79 [range 0.64-1.00] and 0.31 [0.16-0.34], respectively. Multivariate logistic regression analysis revealed that the median FIO2 was associated in a dose-dependent manner with increased risk of respiratory complications (adjusted odds ratio for high vs low FIO2 1.99, 95% confidence interval [1.72-2.31], P -value for trend <0.001). This finding was robust in a series of sensitivity analyses including adjustment for intraoperative oxygenation. High median FIO2 was also associated with 30-day mortality (odds ratio for high vs low FIO2 1.97, 95% confidence interval [1.30-2.99], P -value for trend <0.001).

Conclusions

In this analysis of administrative data on file, high intraoperative FIO2 was associated in a dose-dependent manner with major respiratory complications and with 30-day mortality. The effect remained stable in a sensitivity analysis controlled for oxygenation.

Clinical trial registration

NCT02399878.

Coffee, tea, and caffeine intake and amyotrophic lateral sclerosis mortality in a pooled analysis of eight prospective cohort studies

BACKGROUND AND PURPOSE

Caffeine is associated with a lower risk of some neurological diseases, but few prospective studies have investigated caffeine intake and risk of amyotrophic lateral sclerosis (ALS) mortality. We therefore determined associations between coffee, tea and caffeine intake, and risk of ALS mortality.

METHODS

We conducted pooled analyses of eight international, prospective cohort studies, including 351 565 individuals (120 688 men and 230 877 women). We assessed coffee, tea and caffeine intake using validated food-frequency questionnaires administered at baseline. We used Cox regression to estimate study- and sex-specific risk ratios and 95% confidence intervals (CI) for ALS mortality, which were then pooled using a random-effects model. We conducted analyses using cohort-specific tertiles, absolute common cut-points and continuous measures of all exposures.

RESULTS

During follow-up, 545 ALS deaths were documented. We did not observe statistically significant associations between coffee, tea or caffeine intake and risk of ALS mortality. The pooled multivariable risk ratio (MVRR) for ≥3 cups per day vs. >0 to <1 cup per day was 1.04 (95% CI, 0.74-1.47) for coffee and 1.17 (95% CI, 0.77-1.79) for tea. The pooled MVRR comparing the highest with the lowest tertile of caffeine intake (mg/day) was 0.99 (95% CI, 0.80-1.23). No statistically significant results were observed when exposures were modeled as tertiles or continuously.

CONCLUSIONS

Our results do not support associations between coffee, tea or total caffeine intake and risk of ALS mortality.

Heavy Physics Contributions to Neutrinoless Double Beta Decay from QCD

Observation of neutrinoless double beta decay, a lepton number violating process that has been proposed to clarify the nature of neutrino masses, has spawned an enormous world-wide experimental effort. Relating nuclear decay rates to high-energy, beyond the standard model (BSM) physics requires detailed knowledge of nonperturbative QCD effects. Using lattice QCD, we compute the necessary matrix elements of short-range operators, which arise due to heavy BSM mediators, that contribute to this decay via the leading order π^{-}→π^{+} exchange diagrams. Utilizing our result and taking advantage of effective field theory methods will allow for model-independent calculations of the relevant two-nucleon decay, which may then be used as input for nuclear many-body calculations of the relevant experimental decays. Contributions from short-range operators may prove to be equally important to, or even more important than, those from long-range Majorana neutrino exchange.

Abstract 091: Knock Out of Pappa2 Enhances Blood Pressure Salt-Sensitivity and Renal Injury

Pappa2 (pregnancy associated plasma protein A2) is a protease of insulin-like growth factor binding protein 5 (IGFBP5) which has been primarily studied in pregnancy and post-natal growth. Our recent studies using contiguous congenic strains indicate that Pappa2 is linked to salt-sensitive hypertension in Dahl salt-sensitive (SS) rats. The role of Pappa2 in cardiovascular and renal function has not been studied previously. We therefore mutated Pappa2 in a salt-resistant subcongenic strain 26-P using the CRISPR-Cas9 method. Mutation of the Pappa2 gene resulted in a 60-bp deletion and the absence of the wild type protein in the urine was verified by Western blot analysis. We hypothesized that deletion of Pappa2 in the salt-insensitive strain would return or enhance BP salt-sensitivity as found in SS rats. Both parental rats and weaned offspring were maintained on a 0.4% NaCl diet until 9 weeks of age, then surgically instrumented with radiotelemeters for 24 hr BP recordings obtained while fed 0.4% NaCl and during 21 days of a 4% NaCl diet.

Results: Mean 24 hr arterial pressure at 21 days of a 4.0% salt diet was significantly higher (P<0.05) in male Pappa2-/- (164 + 5 mmHg; n=11) compared to Pappa2+/+ WT (137 + 4 mmHg; n=9) rats. Body weight (9 wks) of Pappa2-/- was less (P<0.05) than weight of Pappa2+/+ WT rats (217 + 7 g vs 281 + 11 g). Although less than expected compared to previously studied SS rats, indices of renal injury were only moderately increased in Pappa2-/- compared to Pappa+/+ WT rats including tubular protein casts (6.509 ± 0.789, n=11 vs 3.8 ± 0.718, n=9; P<0.05), cortical T-lymphocyte (CD3 + /mm 2 ; 96.1 ± 9.9, n=11 vs 70.9 ± 6.8, n=9; P=0.06), macrophage (CD68 + /mm 2 ; 74.6 ± 9.4, n=11 vs 47.6 ± 5.2, n=8; P<0.05), and interstitial smooth muscle actin (4.5 ± 0.4, n=11 vs 3.4 ± 0.2, n=8; P<0.05). In summary, the “rescue” of the BP salt-sensitivity trait with mutation of Pappa2 provides the first direct evidence that this gene plays an important role in renal fluid and electrolyte homeostasis and the regulation of arterial pressure.

Abstract P215: Role of Nox4 - H 2 O 2 Production in Cctivation of mTORC1 in Salt-Induced Hypertension and Kidney Injury in Dahl S Rats

Nox4 is the most abundant NADPH-oxidase isoform in the kidney. It predominantly releases H 2 O 2 and has been shown to contribute importantly to hypertension and renal injury in Dahl salt-sensitive (SS) rats fed a high salt diet. Recently, we reported that systemic inhibition of mTORC1 with chronic rapamycin treatment reduces salt-induced hypertension and kidney injury in SS rats. In the present study, we hypothesized that elevations of H 2 O 2 would activate mTORC1 and that reduction of Nox4 related H 2 O 2 production would reduce the mTORC1 contribution to salt-induced hypertension in SS rats. We first examined the effect of H 2 O 2 on mTORC1 activity in vivo by comparing the activity of mTORC1 in SS rats which have high levels of H 2 O 2 to SS-Nox4 knockout (SS Nox4–/– ) rats which have low levels of renal H 2 O 2 . As analyzed by Western blot, pS6 S235/236 /S6 (index of mTORC1 activity) was found to be significantly lower (P<0.05) in the renal cortex of SS Nox4-/- rats indicating that Nox4 generated H 2 O 2 was upstream in the mTORC1 pathway. We then examined whether systemic inhibition of mTORC1 with chronic rapamycin treatment would fail to reduce salt-sensitivity and kidney injury in nine week old male SS Nox4-/- rats. It was found that mean arterial pressure (MAP) of SS Nox4-/- rats treated with rapamycin (I.P.,1.5 mg/kg/day) fed a high salt diet (4.0%NaCl) for 21 days was not significantly different to vehicle treated SS Nox4-/- rats on the final day 21 (150 ± 7; n=8; vs 145 ± 6 mmHg; n=5; P>0.05). Neither did rapamycin treatment have a significant effect on kidney injury in SS Nox4-/- rats compared to vehicle treated rats determined at day 21 as reflected by albumin excretion rate (8 ± 2 vs 20 ± 13 mg/day, respectively; P>0.05). Rapamycin treated SS Nox4-/- rats exhibited a slow rate of body weight gain (302 ± 14 g at control and 313 ± 12 g at 21 days; P>0.05) compared to vehicle treated rats (316 ± 9 g at control and 366 ± 15 g at 21 days; P<0.05), although average food intake did not differ significantly (P>0.05) between the two groups. We conclude that Nox4 - H 2 O 2 production contributes importantly to mTORC1 activation leading to blood pressure salt-sensitivity, and renal injury in SS rats.

Transcriptomic analysis reveals inflammatory and metabolic pathways that are regulated by renal perfusion pressure in the outer medulla of Dahl-S rats

Studies exploring the development of hypertension have traditionally been unable to distinguish which of the observed changes are underlying causes from those that are a consequence of elevated blood pressure. In this study, a custom-designed servo-control system was utilized to precisely control renal perfusion pressure to the left kidney continuously during the development of hypertension in Dahl salt-sensitive rats. In this way, we maintained the left kidney at control blood pressure while the right kidney was exposed to hypertensive pressures. As each kidney was exposed to the same circulating factors, differences between them represent changes induced by pressure alone. RNA sequencing analysis identified 1,613 differently expressed genes affected by renal perfusion pressure. Three pathway analysis methods were applied, one a novel approach incorporating arterial pressure as an input variable allowing a more direct connection between the expression of genes and pressure. The statistical analysis proposed several novel pathways by which pressure affects renal physiology. We confirmed the effects of pressure on p-Jnk regulation, in which the hypertensive medullas show increased p-Jnk/Jnk ratios relative to the left (0.79 ± 0.11 vs. 0.53 ± 0.10, P < 0.01, n = 8). We also confirmed pathway predictions of mitochondrial function, in which the respiratory control ratio of hypertensive vs. control mitochondria are significantly reduced (7.9 ± 1.2 vs. 10.4 ± 1.8, P < 0.01, n = 6) and metabolomic profile, in which 14 metabolites differed significantly between hypertensive and control medullas ( P < 0.05, n = 5). These findings demonstrate that subtle differences in the transcriptome can be used to predict functional changes of the kidney as a consequence of pressure elevation.

Abstract 105: Therapeutic Suppression of Mtorc2 Signaling Reduces Salt-induced Hypertension and Kidney Injury in SS Rats

The present study explored the protective effect of mTORC2 inhibition in salt-induced hypertension and kidney injury. We have previously reported that enhanced blood pressure salt-sensitivity with renal chronic interstitial infusion of H 2 O 2 (347 nmol/kg/min) in normotensive Sprague Dawley (SD) rats. In the present study, in vivo experiment was performed in which H 2 O 2 (347 nmol/Kg/min) was chronically infused for 3 days into renal interstitium of unilaterally nephrectomized SD rats. A significant increase of mTORC2 activity (pAKT/AKT) was observed in the renal cortex of SD rats infused with H 2 O 2 compared to saline infused rats. We have recently shown that excess production of H 2 O 2 in the SS rat kidneys is the hallmark of salt-induced hypertension. We hypothesized that mTORC2 in the kidney contributes to the development of salt-induced hypertension in SS rats. Rats were treated with PP242 which is an ATP-competitor inhibitor which inhibits the activities of both mTORC1 and mTORC2 whereas rapamycin specifically inhibits mTORC1. PP242 was administrated daily (i.p., 15 mg/Kg/day) for 21 days to SS rats fed a 4.0% NaCl diet. Remarkably, salt-induced hypertension was significantly reduced in SS rats which averaged 119 ± 2 mmHg in PP242 treated rats (n=7) compared to 168 ± 3 mmHg in vehicle treated rats (n=7). Albuminuria was greatly reduced with urine albumin excretion (mg/day) averaging 32.8 ± 3 in PP242 treated rats compared to 256 ± 37 in vehicle treated rats. PP242 treatment notably resulted in reduced infiltration of T lymphocytes in the kidneys of SS rats fed a 4.0% NaCl diet. CD3 + cells/mm 2 averaging 157.0 ± 40.0 compared to 36.0 ± 11.0 in the renal cortex and 218.0 ± 24.0 compared to 24.0 ± 9.0 in the outer medulla in PP242 versus vehicle treated rats. These data show that mTORC2 is required for the intiation of salt-induced hypertension and therapeutic suppression of this pathway virtually abolished salt-sensitivity blood pressure and kidney injury.

Inhibition of Mammalian Target of Rapamycin Complex 1 Attenuates Salt-Induced Hypertension and Kidney Injury in Dahl Salt-Sensitive Rats

The goal of the present study was to explore the protective effects of mTORC1 (mammalian target of rapamycin complex 1) inhibition by rapamycin on salt-induced hypertension and kidney injury in Dahl salt-sensitive (SS) rats. We have previously demonstrated that H₂O₂ is elevated in the kidneys of SS rats. The present study showed a significant upregulation of renal mTORC1 activity in the SS rats fed a 4.0% NaCl for 3 days. In addition, renal interstitial infusion of H₂O₂ into salt-resistant Sprague Dawley rats for 3 days was also found to stimulate mTORC1 activity independent of a rise of arterial blood pressure. Together, these data indicate that the salt-induced increases of renal H₂O₂ in SS rats activated the mTORC1 pathway. Daily administration of rapamycin (IP, 1.5 mg/kg per day) for 21 days reduced salt-induced hypertension from 176.0±9.0 to 153.0±12.0 mm Hg in SS rats but had no effect on blood pressure salt sensitivity in Sprague Dawley treated rats. Compared with vehicle, rapamycin reduced albumin excretion rate in SS rats from 190.0±35.0 to 37.0±5.0 mg/d and reduced the renal infiltration of T lymphocytes (CD3⁺) and macrophages (ED1⁺) in the cortex and medulla. Renal hypertrophy and cell proliferation were also reduced in rapamycin-treated SS rats. We conclude that enhancement of intrarenal H₂O₂ with a 4.0% NaCl diet stimulates the mTORC1 pathway that is necessary for the full development of the salt-induced hypertension and kidney injury in the SS rat.

Increased Perfusion Pressure Drives Renal T-Cell Infiltration in the Dahl Salt-Sensitive Rat

Renal T-cell infiltration is a key component of salt-sensitive hypertension in Dahl salt-sensitive (SS) rats. Here, we use an electronic servo-control technique to determine the contribution of renal perfusion pressure to T-cell infiltration in the SS rat kidney. An aortic balloon occluder placed around the aorta between the renal arteries was used to maintain perfusion pressure to the left kidney at control levels, ≈128 mm Hg, during 7 days of salt-induced hypertension, whereas the right kidney was exposed to increased renal perfusion pressure that averaged 157±4 mm Hg by day 7 of high-salt diet. The number of infiltrating T cells was compared between the 2 kidneys. Renal T-cell infiltration was significantly blunted in the left servo-controlled kidney compared with the right uncontrolled kidney. The number of CD3⁺, CD3⁺CD4⁺, and CD3⁺CD8⁺ T cells were all significantly lower in the left servo-controlled kidney. This effect was not specific to T cells because CD45R⁺ (B cells) and CD11b/c⁺ (monocytes and macrophages) cell infiltrations were all exacerbated in the hypertensive kidneys. Increased renal perfusion pressure was also associated with augmented renal injury, with increased protein casts and glomerular damage in the hypertensive kidney. Levels of norepinephrine were comparable between the 2 kidneys, suggestive of equivalent sympathetic innervation. Renal infiltration of T cells was not reversed by the return of renal perfusion pressure to control levels after 7 days of salt-sensitive hypertension. We conclude that increased pressure contributes to the initiation of renal T-cell infiltration during the progression of salt-sensitive hypertension in SS rats.

[Public Health: Setting Goals, Establishing Structures and Improving Health for All]

Public health is a population- and system-based approach that is needed to improve the health of societies and to decrease health inequalities. In the face of global challenges, the public health approach is essential. In Germany, the importance of public health is only partly reflected by its institutions and institutional arrangements. This applies equally to research, teaching and training, as well as to the public health service. Furthermore, the public health perspective is not sufficiently considered in cross-sectional topics that are relevant for health.There have been several initiatives to overcome structural deficits which can partly be traced back to historical circumstances. The White Paper presented here should encourage discussions about future policy options in public health. The authors represent public health in practice, research, and teaching in Germany.

Breaking the Cycle: Estrous Variation Does Not Require Increased Sample Size in the Study of Female Rats

Despite the striking differences between male and female physiology, female physiology is understudied. In response, the National Institutes of Health is promulgating new policies to increase the use of female organisms in preclinical research. Females are commonly believed to have greater variability than males because of the estrous cycle, but recent studies call this belief into question. Effects of estrous cycling on mean arterial pressure were assessed in female Dahl S rats using telemetry and vaginal cytometry and found that estrous cycling did not affect mean arterial pressure magnitude or variance. Data from the PhysGen arm of the Program for Genomic Applications was used to compare male and female variance and coefficient of variation in 142 heart, lung, vascular, kidney, and blood phenotypes, each measured in hundreds to thousands of individual rats from over 50 inbred strains. Seventy-four of 142 phenotypes from this data set demonstrated a sex difference in variance; however, 59% of these phenotypes exhibited greater variance in male rats rather than female. Remarkably, a retrospective power analysis demonstrated that only 16 of 74 differentially variable phenotypes would be detected when using an experimental cohort large enough to detect a difference in magnitude. No overall difference in coefficient of variation between male and female rats was detected when analyzing these 142 phenotypes. We conclude that variability of 142 traits in male and female rats is similar, suggesting that differential treatment of males and females for the purposes of experimental design is unnecessary until proven otherwise, rather than the other way around.

Abstract 120: Reversal of Hypertension Stops, but Does Not Reverse, Renal T-cell Infiltration in the Dahl Salt-sensitive Rat

In previous chronic servo control experiments we showed that increased renal perfusion pressure (RPP) amplifies renal T-cell infiltration in Dahl salt-sensitive (SS) rats. Renal T-cell infiltration was significantly higher in the right-hypertensive kidneys vs. the left servo-controlled kidneys of SS rats fed high salt (HS) for 7-days. There was no significant difference in T-cell infiltration in sham rats (both kidneys exposed to comparable RPPs). Here we use the chronic servo control system to determine whether the reversal of salt-sensitive hypertension reverses renal T-cell infiltration in SS rats.

An aortic balloon occluder was placed around the aorta, between the renal arteries to electronically servo-control RPP to the left kidney. Arterial catheters were used to measure MAP above and below the occluder (n=5).

Baseline RPPs were measured on a control salt diet (0.4% NaCl) for 3-days (average left RPP, 124±1mmHg) after which rats were switched to a HS diet (4.0% NaCl) for 14-days. During the first 7-days of HS both kidneys were exposed to uncontrolled hypertension. After 7-days a servo control system was used to bring the RPP to the left kidney (the reversal kidney) back to the average control level, where it was held for the next 7-days of HS (from 139±2mmHg to 125±2mmHg). It was found that reversal of hypertension prevented a further increase of renal T-cell infiltration but the number of infiltrated T-cells did not diminish. Moreover, the number of T-cells in the left-reversal kidney was significantly higher than in the continuously-controlled, left-servo kidney despite comparable final RPPs (129±2mmHg to the left-servo kidney vs. 125±2mmHg to the left-reversal kidney). T-cell infiltration in the left-reversal kidney was comparable to the left-sham kidneys, in which in the final RPP was 148±2mmHg.

In ‘T-cells per kidney’-

CD3+ (mature): Reversal=287x10 3 ±65x10 3 Servo=78x10 3 ±12x10 3 Sham=186x10 3 ±47x10 3 .

CD3+CD4+ (helper): Reversal=95x10 3 ±27x10 3 Servo=32x10 3 ±5x10 3 Sham=86x10 3 ±26x10 3 .

CD3+CD8+ (cytotoxic): Reversal=196x10 3 ±42x10 3 Servo=42x10 3 ±7x10 3 Sham=102,082x10 3 ±23x10 3

We conclude that reversal of blood pressure alone, for 1-week, while HS intake is continued, stops but does not reverse renal T-cell infiltration in SS rats.

The G1246A Polymorphism in the Hypocretin Receptor 2 Gene is not Associated with Treatment Response in Cluster Headache

The risk of cluster headache (CH) is associated with the G-allele of the G1246A polymorphism in the hypocretin receptor 2 ( HCRTR2) gene. First-line medication is effective in only about 70-80% of CH patients. We hypothesized that the HCRTR2 G1246A polymorphism is also of pharmacogenetic relevance in CH and may affect treatment response. We performed a prospective cohort study among 184 unrelated White CH patients. While the HCRTR2 1246G allele was significantly associated with CH in this group, treatment outcomes with triptans, oxygen, verapamil and corticosteroids remained unaffected. Our results do not support a role of the HCRTR2 G1246A polymorphism in drug responses in CH.

Predictors of Hazardous Alcohol Consumption among Patients with Cluster Headache

The purpose of this study was to identify predictors of hazardous alcohol consumption in patients with cluster headache (CH). We investigated 246 German CH patients with the Alcohol Use Disorders Identification Test (AUDIT). The average daily alcohol consumption was 6.5 g. Predictors for hazardous drinking (AUDIT ≥ 5 points; 21.5% of patients) were male gender [odds ratio (OR) 4.15, 95% confidence interval (CI) 1.35, 12.71], episodic as opposed to chronic CH (OR 4.8, 95% CI 1.38, 16.67) and a low demanding job as opposed to a high demanding job (OR 2.28, 95% CI 1.15, 4.51). Our data indicate that CH patients drink less alcohol compared with the German population and that CH seems to protect against hazardous alcohol consumption. Moreover, predictors for hazardous alcohol consumption in CH patients are not different from the general population.

Evidence of the Importance of Nox4 in Production of Hypertension in Dahl Salt-Sensitive Rats

This study reports the consequences of knocking out NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 4 (Nox4) on the development of hypertension and kidney injury in the Dahl salt-sensitive (SS) rat. Zinc finger nuclease injection of single-cell SS embryos was used to create an 8 base-pair frame-shift deletion of Nox4, resulting in a loss of the ≈68 kDa band in Western blot analysis of renal cortical tissue of the knock out of Nox4 in the SS rat (SS(Nox4-/-)) rats. SS(Nox4-/-) rats exhibited a significant reduction of salt-induced hypertension compared with SS rats after 21 days of 4.0% NaCl diet (134±5 versus 151±3 mm Hg in SS) and a significant reduction of albuminuria, tubular casts, and glomerular injury. Optical fluorescence 3-dimensional cryoimaging revealed significantly higher redox ratios (NADH/FAD [reduced nicotinamide adenine dinucleotide/flavin adenine dinucleotide]) in the kidneys of SS(Nox4-/-) rats even when fed the 0.4% NaCl diet, indicating greater levels of mitochondrial electron transport chain metabolic activity and reduced oxidative stress compared with SS rats. Before the development of hypertension, RNA expression levels of Nox subunits Nox2, p67(phox), and p22(phox) were found to be significantly lower (P<0.05) in SS(Nox4-/-) compared with SS rats in the renal cortex. Thus, the mutation of Nox4 seems to modify transcription of several genes in ways that contribute to the protective effects observed in the SS(Nox4-/-) rats. We conclude that the reduced renal injury and attenuated blood pressure response to high salt in the SS(Nox4-/-) rat could be the result of multiple pathways, including gene transcription, mitochondrial energetics, oxidative stress, and protein matrix production impacted by the knock out of Nox4.

Pappa2 is linked to salt-sensitive hypertension in Dahl S rats

A 1.37 Mbp region of chromosome 13 previously identified by exclusion mapping was consistently associated with a reduction of salt-induced hypertension in the Dahl salt-sensitive (SS) rat. This region contained five genes that were introgressed from the salt-insensitive Brown Norway (BN) rat. The goal of the present study was to further narrow that region to identify the gene(s) most likely to protect from salt-induced hypertension. The studies yielded a subcongenic SS rat strain containing a 0.71 Mbp insert from BN (26-P strain) in which salt-induced hypertension was reduced by 24 mmHg. The region contained two protein-coding genes (Astn1 and Pappa2) and a microRNA (miR-488). Pappa2 mRNA in the renal cortex of the protected 26-P was 6- to 10-fold greater than in SS fed a 0.4% NaCl diet but was reduced to levels observed in SS when fed 8.0% NaCl diet for 7 days. Compared with brain nuclei (NTS, RVLM, CVLM) and the adrenal gland, Pappa2 in the renal cortex was the only gene found to be differentially expressed between SS and 26-P and that responded to changes of salt diet. Immunohistochemistry studies found Pappa2 localized in the cytosol of the epithelial cells of the cortical thick ascending limbs. In more distal segments of the renal tubules, it was observed within tubular lumens and most notably bound to the apical membranes of the intercalated cells of collecting ducts. We conclude that we have identified a variant form of Pappa2 that can protect against salt-induced hypertension in the Dahl S rat.

Abstract 044: Pappa2 is Linked to Salt-sensitive Hypertension in Dahl SS Rats

The goal of the present study was to narrow a 1.37 Mbp region containing five genes on chromosome 13 (positions 80.92-82.29 Mbp in the Rn5 genome assembly) that we have previously found to influence the mean arterial pressure (MAP) by at least 25 mmHg in SS rats fed a high salt diet (8.0% NaCl for 14 days). The creation of 6 overlapping subcongenic strains that cover this region identified a 0.71 Mbp region (positions 81.01-81.72 Mbp) in which substitution of SS alleles with BN alleles reduced salt-induced hypertension in congenic SS rats by nearly 30 mmHg and significantly reduced urinary albumin excretion (UalbV) (see figure below; n=10-15/strain; * significant difference from SS; p<0.05). Analysis of the narrow candidate region revealed the presence of two protein-coding genes ( Pappa2 and Astn1 ) and a microRNA ( miR488 ), none of which are known to be mechanistically involved in hypertension. Pappa2 mRNA in these rat strains fed 0.4% NaCl diet was expressed at 6-10 fold higher levels in the renal cortex of the salt-resistant congenic strains with the BN allele (26-N, -O, and [[Unable to Display Character: &#8211;]]P) compared to strains with the SS allele (26-Q, -R, and [[Unable to Display Character: &#8211;]]S). A Pappa2 coding sequence variant of unknown functional importance was identified. Immunohistochemistry and fluorescence in situ hybridization studies localized Pappa2 to intercalated cells of the cortical and medullary collecting duct. Astn1 and miR-488 were not differentially expressed in renal tissue. Together, these findings point towards Pappa2 as a candidate gene for salt-induced hypertension in SS rats.

Abstract 103: Increased Blood Pressure Drives Renal T-cell Infiltration in the Dahl Salt-Sensitive Rat

Previous studies have shown that renal T-cell infiltration is a key component of salt-sensitive hypertension in Dahl salt-sensitive (SS) rats. Here we used chronic servo control experiments to determine the contribution of renal perfusion pressure (RPP) to T-cell infiltration in the SS rat kidney. An aortic balloon occluder was placed around the aorta, between the renal arteries, and used to maintain blood pressure to the left kidney at control levels, ~128 mmHg, during 7-days of salt induced hypertension. During the same period, the right kidney was exposed to increased RPP, averaging 158 ± 4 mmHg by high salt (4% NaCl) day-7. The number of infiltrating T-cells was compared between the two kidneys. Renal T-cell infiltration was significantly blunted in the left-servo controlled kidney compared to the right-uncontrolled kidney. The number of mature (CD3+), helper (CD3+CD4+) and cytotoxic T-cells (CD3+CD8+) were all significantly lower in the servo controlled kidney than in the hypertensive kidney (Fig.1). This effect was not specific to T-cells, monocyte, macrophage and B-cell infiltration were all significantly exacerbated in the hypertensive kidney. Increased RPP was also associated with augmented renal injury, with increased protein casts and glomeruli damage in the hypertensive kidney. We conclude that during the development of salt-sensitive hypertension increased RPP contributes to renal T-cell infiltration in SS rats; when blood pressure is maintained at control levels T-cell infiltration is significantly attenuated in the servo-controlled kidney relative to the hypertensive kidney despite exposure to comparable sympathetic drive and circulating factors.

Effects of p67phox on the mitochondrial oxidative state in the kidney of Dahl salt-sensitive rats: optical fluorescence 3-D cryoimaging

The goal of the present study was to quantify and correlate the contribution of the cytosolic p67(phox) subunit of NADPH oxidase 2 to mitochondrial oxidative stress in the kidneys of the Dahl salt-sensitive (SS) hypertensive rat. Whole kidney redox states were uniquely assessed using a custom-designed optical fluorescence three-dimensional cryoimager to acquire multichannel signals of the intrinsic fluorophores NADH and FAD. SS rats were compared with SS rats in which the cytosolic subunit p67(phox) was rendered functionally inactive by zinc finger nuclease mutation of the gene (SS(p67phox)-null rats). Kidneys of SS rats fed a 0.4% NaCl diet exhibited significantly (P = 0.023) lower tissue redox ratio (NADH/FAD; 1.42 ± 0.06, n = 5) than SS(p67phox)-null rats (1.64 ± 0.07, n = 5), indicating reduced levels of mitochondrial electron transport chain metabolic activity and enhanced oxidative stress in SS rats. When fed a 4.0% salt diet for 21 days, both strains exhibited significantly lower tissue redox ratios (P < 0.001; SS rats: 1.03 ± 0.05, n = 9, vs. SS(p67phox)-null rats: 1.46 ± 0.04, n = 7) than when fed a 0.4% salt, but the ratio was still significantly higher in SS(p67phox) rats at the same salt level as SS rats. These results are consistent with results from previous studies that found elevated medullary interstitial fluid concentrations of superoxide and H2O2 in the medulla of SS rats. We conclude that the p67(phox) subunit of NADPH oxidase 2 plays an important role in the excess production of ROS from mitochondria in the renal medulla of the SS rat.

Null mutation of the nicotinamide adenine dinucleotide phosphate-oxidase subunit p67phox protects the Dahl-S rat from salt-induced reductions in medullary blood flow and glomerular filtration rate

Null mutations in the p67(phox) subunit of nicotinamide adenine dinucleotide phosphate-oxidase confer protection from salt sensitivity on Dahl salt-sensitive rats. Here, we track the sequential changes in medullary blood flow (MBF), glomerular filtration rate (GFR), urinary protein, and mean arterial pressure in SSp67(phox) null rats and wild-type littermates during 21 days of 4.0% NaCl high-salt (HS) diet. Optical fibers were implanted in the renal medulla and MBF was measured in conscious rats by laser Doppler flowmetry. Separate groups of rats were prepared with femoral venous catheters and GFR was measured by the transcutaneous assessment of fluorescein isothiocyanate-sinistrin disappearance curves. Mean arterial blood pressure was measured by telemetry. In wild-type rats, HS caused a rapid reduction in MBF, which was significantly lower than control values by HS day-6. Reduced MBF was associated with a progressive increase in mean arterial pressure, averaging 170±5 mm Hg by HS salt day-21. A significant reduction in GFR was evident on day-14 HS, after the onset of hypertension and reduced MBF. In contrast, HS had no significant effect on MBF in SSp67(phox) null rats and the pressor response to sodium was blunted, averaging 150±3 mm Hg on day-21 HS. GFR was maintained throughout the study and proteinuria was reduced. In summary, when p67(phox) is not functional in the salt-sensitive rats, HS does not cause reduced MBF and salt-sensitive hypertension is attenuated, and consequently renal injury is reduced and GFR is maintained.

Lifetime prevalence and underdiagnosis of migraine in a population sample of Mexican women

OBJECTIVE

The objective of this report is to evaluate migraine, migraine characteristics, and underdiagnosis of migraine in a large population sample of Mexican women.

METHODS

Participants are part of a prospective cohort of Mexican teachers. Between 2011 and 2013, 77,855 participants completed a detailed questionnaire on headache characteristics. Migraine was defined according to criteria of the International Classification of Headache Disorders (ICDH-II).

RESULTS

We found lifetime migraine prevalence was 19%, prevalence peaked at 40-44 years (20.4%) and only 45.1% participants with migraine had a previous diagnosis of the disease.

CONCLUSION

Estimated lifetime prevalence of migraine was higher than previous reports in Latin America. Migraine may be underdiagnosed and undertreated in Mexico despite its considerable burden.

Abstract 665: Cryofluorescence 3D Imaging Shows Mutation of p67phox Improves Metabolic Function and Reduces Oxidative Stress in the Renal Medulla of the Dahl Salt-sensitive Rat

The Dahl salt-sensitive (SS) rat exhibits increased renal production of reactive oxygen species (ROS) especially in the renal outer medulla (OM) which is known to contribute importantly to the salt-induced hypertension. We have identified increased expression of the p67 phox cytosolic subunit of NAD(P)H oxidase and enhanced enzyme activity in the OM of Dahl salt-sensitive (SS). We found that ZFN knock down of the NADPH-oxidase cytosolic subunit p67 phox in SS rats (SS p67phox-/- ) resulted in a 40% reduction of hypertension and a substantial reduction of renal injury. To determine whether these protective effects were associated with alterations of regional metabolism and oxidative stress, a custom designed cryoimager was used to acquire multi-channel fluorescent images of sequential serial sections with a z-resolution of 30 μm yielding 400 slices per kidney. Computer reconstruction of the stacked sections provided a 3D image of regional changes of metabolic function and oxidative stress within the kidney. Kidneys obtained from SS and SS p67phox-/- rats fed a high salt diet (4% NaCl) for 21 days were flash frozen in liquid N 2 and fluorescent images of the mitochondrial electron transport chain carriers NADH and FAD were acquired. The naturally fluorescent NADH and FAD levels were acquired to provide a 3D representation of the metabolic state of the tissue and oxidative stress. The mean NADH redox ratio (NADH/FAD RR) was significantly higher in kidneys of SS p67phox-/- rats (1.46 ± 0.11 NADH/FAD RR; n=7) compared to SS kidneys (1.00 ± 0.07 NADH/FAD RR; n=4). This represents an average 46% increase in the electron transport chain metabolic activity and a reduction of oxidative stress in kidneys of SS p67phox-/- rats compared to the SS kidneys. Importantly, this was observed only in the region of the renal medulla as revealed by the 3D images of these kidneys. We conclude that p67(phox) is critically involved in cell energetics and ROS production in the renal medulla.

Characterization of biological pathways associated with a 1.37 Mbp genomic region protective of hypertension in Dahl S rats

The goal of the present study was to narrow a region of chromosome 13 to only several genes and then apply unbiased statistical approaches to identify molecular networks and biological pathways relevant to blood-pressure salt sensitivity in Dahl salt-sensitive (SS) rats. The analysis of 13 overlapping subcongenic strains identified a 1.37 Mbp region on chromosome 13 that influenced the mean arterial blood pressure by at least 25 mmHg in SS rats fed a high-salt diet. DNA sequencing and analysis filled genomic gaps and provided identification of five genes in this region, Rfwd2, Fam5b, Astn1, Pappa2, and Tnr. A cross-platform normalization of transcriptome data sets obtained from our previously published Affymetrix GeneChip dataset and newly acquired RNA-seq data from renal outer medullary tissue provided 90 observations for each gene. Two Bayesian methods were used to analyze the data: 1) a linear model analysis to assess 243 biological pathways for their likelihood to discriminate blood pressure levels across experimental groups and 2) a Bayesian graphical modeling of pathways to discover genes with potential relationships to the candidate genes in this region. As none of these five genes are known to be involved in hypertension, this unbiased approach has provided useful clues to be experimentally explored. Of these five genes, Rfwd2, the gene most strongly expressed in the renal outer medulla, was notably associated with pathways that can affect blood pressure via renal transcellular Na(+) and K(+) electrochemical gradients and tubular Na(+) transport, mitochondrial TCA cycle and cell energetics, and circadian rhythms.

Telomere length and Parkinson's disease in men: a nested case-control study

BACKGROUND AND PURPOSE

Telomere shortening has been implicated in neurodegenerative disorders. However, available data on the association between telomere length and Parkinson's disease (PD) are inconclusive.

METHODS

A nested case-control design was used amongst men participating in the prospective Physicians' Health Study. A large proportion of participants provided blood samples in 1997 and they were followed through 2010. Men with self-reported PD were age-matched to controls in a 1:2 ratio. Quantitative PCR was used to determine the telomere repeat copy number to single gene copy number ratio (TSR) in genomic DNA extracted from peripheral blood leukocytes. TSR was used as a measure for relative telomere length (RTL) in our analyses. Conditional logistic regression was used to determine the risk of PD associated with RTL.

RESULTS

Data on RTL were available from 408 cases and 809 controls. Median TSR was shorter in controls than in cases (47.7 vs. 50.2; P = 0.02). The age-adjusted odds ratio (OR) for PD was 0.66 [95% confidence interval (CI) 0.46-0.95; Ptrend over quartiles 0.02] comparing the lowest to the highest quartile. The pattern of association was unchanged when comparing RTL below versus above the median (age-adjusted OR 0.75; 95% CI 0.59-0.96). Associations were similar after additional adjustment for many covariates.

CONCLUSION

Contrary to what was expected, in this large nested case-control study amongst men shorter telomeres were associated with reduced PD risk. Future research on the nature of this counterintuitive association is warranted.

Abstract 78: Protective Effect of Nox4 in Salt-induced Hypertension in Dahl Salt-induced Rats

It is recognized that oxidative stress plays a critical role in the development of salt-sensitive hypertension, especially in the kidney. The most abundant renal isoform is Nox4, but there is controversy regarding its distribution and function. There have been no studies of the role of Nox4 in a naturally occurring form of hypertension (Dahl salt-sensitive (SS) rat). We have therefore knocked out the Nox4 gene in the SS genetic background (SS Nox4-/- ) to determine the effect upon the development of salt-sensitive hypertension and renal kidney injury in the SS rat. The SS Nox4-/- rat, developed using zinc finger nuclease (ZFN) techniques, exhibits an 8 base-pair frame-shift deletion within exon 7 resulting in a truncation of the Nox4 peptide by 195 amino acids with a molecular weight of 22 kD predicted (compared to the full length Nox4 peptide of 594 amino acids with a molecular weight of 68 kD). Western blot analysis confirmed the loss of the Nox4 band at ~65 kD in renal medullary tissue of SS Nox4-/- rats vs. SS. The functional consequence of this deletion was substantial over a 21 day period following an increase in salt intake from 0.4 (LS) to 4.0% NaCl (HS). SS Nox4-/- rats exhibited a change in MAP from 105±3 on LS to 130±2 mmHg (a change of 25 mmHg; n=10) on d21 of HS compared to a change from 107±2 mmHg in SS rats to 171±7 on d21 of HS (a change of 64 mmHg; n=10) as determined by telemetry. Albuminuria was virtually eliminated in SS Nox4-/- rats who also exhibited a large reduction of tubular cast (2.4±0.3% positive strained region vs 12.6±1.3 in SS). Glomerular injury in both the cortex and medulla was significantly less in the SS Nox4-/- than the SS. The % of glomeruli with an injury score of >2 (0-4 scale) was 43±1.5% (258 of 600 glomeruli) in the SS Nox4-/- but 65±3.9% (390 of 600) in the SS. We conclude that Nox4 plays an important role in the development of this form of salt-sensitive hypertension and renal injury in SS rats.

Biomarkers and functional outcomes from ischaemic cerebral events in women: a prospective cohort study

BACKGROUND AND PURPOSE

Several biomarkers have been associated with an increased risk of ischaemic stroke. However, the association between these biomarkers and functional outcome from cerebral ischaemic events is unclear. We aimed to assess the patterns of association between cardiovascular disease biomarkers and functional outcomes after incident ischaemic cerebral events in women.

METHODS

Prospective cohort study of 27,728 women enrolled in the Women's Health Study who provided information on blood samples and were free of stroke or transient ischaemic attack (TIA) at baseline. Multinomial logistic regression was used to determine the association between elevated biomarker levels and functional outcomes from ischaemic cerebral events. Possible functional outcomes included TIA and ischaemic stroke with modified Rankin Scale (mRS) score of 0-1, 2-3, or 4-6.

RESULTS

After a mean follow-up of 15.1 years, 461 TIAs and 380 ischaemic strokes occurred. Elevated levels of total cholesterol were associated with the highest risk of poor functional outcome (mRS 4-6) after incident cerebral ischaemic events (relative risk = 2.02, 95% CI = 1.18-3.46). We observed significant associations between elevated levels of total cholesterol, Lp(a), C-reactive protein, and triglycerides, and mild or moderate functional outcomes after ischaemic cerebral events. Elevations in all other biomarkers were not significantly associated with functional outcomes.

CONCLUSIONS

Whilst total cholesterol level was associated with highest risks of poor functional outcome after stroke, we overall observed an inconsistent pattern of association between biomarkers linked with an increased risk of vascular events and more impaired functional outcomes from stroke.

Incidence of progressive multifocal leukoencephalopathy in patients without HIV

OBJECTIVE

To estimate the incidence rate (IR) of progressive multifocal leukoencephalopathy (PML) in patients without HIV.

METHODS

Within a large US health insurer database between January 2000 and June 2008, we conducted a retrospective observational study. We identified people with autoimmune diseases, chronic lymphocytic leukemia (CLL), non-Hodgkin lymphoma (NHL), or history of bone marrow or solid organ transplantation, and a general population cohort. We developed a PML case-finding algorithm and validated PML diagnoses in medical charts.

RESULTS

There were 138,469 patients with autoimmune diseases, 25,706 with NHL or CLL, and 8,778 with transplants. Among 699 people who met screening criteria for potential PML, 89 had a claim diagnosis of PML (International Classification of Diseases-9 046.3). Medical records were sought for 24 patients without HIV, and 6 had confirmed PML upon review of medical records. The PML IR was 2.4 (95% confidence interval [CI] 0.06-13.18) in the systemic lupus erythematosus cohort and 10.8 (95% CI 0.27-60.39) in the autoimmune vasculitis cohort per 100,000 person-years. In the NHL and CLL cohorts, the IR was 8.3 (95% CI 1.71-24.24) and 11.1 (0.28-61.74) per 100,000 person-years. The IR among patients with bone marrow transplantation was 35.4 per 100,000 person-years (95% CI 0.90-197.29). There were no cases of PML among patients with rheumatoid arthritis (95% CI 0.0-2.24), multiple sclerosis (95% CI 0.0-5.24), Sjögren disease (95% CI 0.0-21.84), or solid organ transplantation (95% CI 0.0-26.81).

CONCLUSIONS

In this large population-based investigation of PML with thorough case finding and a known source population, the IR of medical record-confirmed PML was rare in non-HIV patient cohorts.

Migraine and cardiovascular disease: a population-based study

OBJECTIVES

Although the relationship between migraine and cardiovascular disease (CVD) has been studied, several questions remain unanswered. Herein we contrast the rate of diagnosed CVD as well as of risk factors for CVD in individuals with migraine with and without aura (MA and MO) and in controls.

METHODS

In this case-control study, migraineurs (n = 6,102) and controls (n = 5,243) were representative of the adult US population. Headache diagnosis was formally assigned using a validated mailed questionnaire which also obtained details on treatment, comorbidities, and other variables. CVD events were obtained based on self-reported medical diagnosis. Risk factors for CVD and modified Framingham scores were computed.

RESULTS

In unadjusted analyses, migraine overall and MA were associated with myocardial infarction, stroke, and claudication, and MO was associated with myocardial infarction and claudication. Migraineurs were more likely than controls to have a medical diagnosis of diabetes (12.6% vs 9.4%, odds ratio [OR] 1.4, 95% confidence interval [CI] 1.2-1.6), hypertension (33.1% vs 27.5%, OR 1.4, 95% CI 1.3-1.6), and high cholesterol (32.7% vs 25.6%, OR 1.4, 95% CI 1.3-1.5). Risk was highest in MA, but remained elevated in MO. Framingham scores were significantly higher in MO and MA than in controls. After adjustments (gender, age, disability, treatment, CVD risk factors), migraine remained significantly associated with myocardial infarction (OR 2.2, 95% CI 1.7-2.8), stroke (OR 1.5, 95% CI 1.2-2.1), and claudication (OR 2.69, 95% CI 1.98-3.23).

CONCLUSION

Both migraine with and without aura are associated with cardiovascular disease (CVD) and with risk factors for CVD. However, since our sample size is large, the clinical relevance of the differences is yet to be established.