Depletion of macrophages slows the early progression of renal injury in obese Dahl salt-sensitive leptin receptor mutant rats

Recently, we reported that obese Dahl salt-sensitive (SS) leptin receptor mutant (SS^LepRmutant) rats display progressive renal injury. The present study demonstrated that the early development of renal injury in the SS^LepRmutant strain is associated with an increase in the renal infiltration of macrophages compared with lean SS rats. We also examined whether depletion of macrophages with clodronate would reduce the early progression of renal injury in the SS^LepRmutant strain. Four-week-old SS and SS^LepRmutant rats were treated with either vehicle (PBS) or clodronate (50 mg/kg ip, 2 times/wk) for 4 wk. While the administration of clodronate did not reduce renal macrophage infiltration in SS rats, clodronate decreased macrophages in the kidneys of SS^LepRmutant rats by >50%. Interestingly, clodronate significantly reduced plasma glucose, insulin, and triglyceride levels and markedly improved glucose tolerance in SS^LepRmutant rats. Treatment with clodronate had no effect on the progression of proteinuria or renal histopathology in SS rats. In the SS^LepRmutant strain, proteinuria was markedly reduced during the first 2 wk of treatment (159 ± 32 vs. 303 ± 52 mg/day, respectively). However, after 4 wk of treatment, the effect of clodronate was no longer observed in the SS^LepRmutant strain (346 ± 195 vs. 399 ± 50 mg/day, respectively). The kidneys from SS^LepRmutant rats displayed glomerular injury with increased mesangial expansion and renal fibrosis versus SS rats. Treatment with clodronate significantly decreased glomerular injury and renal fibrosis in the SS^LepRmutant strain. Overall, these data indicate that the depletion of macrophages improves metabolic disease and slows the early progression of renal injury in SS^LepRmutant rats.

NLRP3 inflammasome activation in platelets in response to sepsis

Sepsis is a complex syndrome characterized by organ dysfunction and a dysregulated immune host response to infection. There is currently no effective treatment for sepsis, but platelets have been proposed as a potential therapeutic target for the treatment of sepsis. We hypothesized that the NLRP3 inflammasome is activated in platelets during sepsis and may be associated with multiorgan injury in response to polymicrobial sepsis. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in 12‐ to 13‐week‐old male Sprague–Dawley rats. The necrotic cecum was removed at 24 h post‐CLP. At 72 h post‐CLP, activated platelets were significantly increased in CLP versus Sham rats. Colocalization of NLRP3 inflammasome components was observed in platelets from CLP rats at 72 h post‐CLP. Plasma, pulmonary, and renal levels of IL‐1β and IL‐18 were significantly higher in CLP rats compared to Sham controls. Soluble markers of endothelial permeability were increased in CLP versus Sham. Renal and pulmonary histopathology were markedly elevated in CLP rats compared to Sham controls. NLRP3 is activated in platelets in response to CLP and is associated with inflammation, endothelial permeability and multiorgan injury. Our results indicate that activated platelets may play a role to cause multiorgan injury in sepsis and may have therapeutic potential for the treatment of sepsis multiorgan injury.

Altered renal hemodynamics is associated with glomerular lipid accumulation in obese Dahl salt-sensitive leptin receptor mutant rats

The present study examined whether development of renal injury in the nondiabetic obese Dahl salt-sensitive leptin receptor mutant (SS^LepRmutant) strain is associated with elevations in glomerular filtration rate and renal lipid accumulation. Baseline mean arterial pressure at 6 wk of age was similar between Dahl salt-sensitive wild-type (SS_WT) and SS^LepRmutant rats. However, by 18 wk of age, the SS^LepRmutant strain developed hypertension, while the elevation in mean arterial pressure was not as severe in SS_WT rats (192 ± 4 and 149 ± 6 mmHg, respectively). At baseline, proteinuria was fourfold higher in SS^LepRmutant than SS_WT rats and remained elevated throughout the study. The early development of progressive proteinuria was associated with renal hyperfiltration followed by a decline in renal function over the course of study in the SS^LepRmutant compared with SS_WT rats. Kidneys from the SS^LepRmutant strain displayed more glomerulosclerosis and glomerular lipid accumulation than SS_WT rats. Glomeruli were isolated from the renal cortex of both strains at 6 and 18 wk of age, and RNA sequencing was performed to identify genes and pathways driving glomerular injury. We observed significant increases in expression of the influx lipid transporters, chemokine (C-X-C motif) ligand 16 (Cxcl16) and scavenger receptor and fatty acid translocase (Cd36), respectively, and a significant decrease in expression of the efflux lipid transporter, ATP-binding cassette subfamily A member 2 (Abca2; cholesterol efflux regulatory protein 2), in SS^LepRmutant compared with SS_WT rats at 6 and 18 wk of age, which were validated by RT-PCR analysis. These data suggest an association between glomerular hyperfiltration and glomerular lipid accumulation during the early development of proteinuria associated with obesity.

Socioeconomic inequalities and the equity impact of population-level interventions for adolescent health: an overview of systematic reviews

OBJECTIVES

Despite robust evidence on health inequalities in adulthood, less attention has been paid to inequalities in adolescence. The aim of this overview was to examine systematic review (SR) evidence on the equity impact of population-level interventions intended to improve health, happiness and wellbeing for adolescents.

STUDY DESIGN

An overview (review of systematic reviews).

METHODS

Eleven electronic databases were systematically searched to identify SRs of population-level interventions for adolescent health. A secondary data analysis of socioeconomic inequality was conducted to identify whether SRs reported on primary studies in terms of disadvantage, by measures of socioeconomic status (SES) and by differential effects.

RESULTS

35,310 review titles were screened; 566 full texts were retrieved and 140 SRs met the predefined selection criteria. Differential intervention effects were considered in 42/140 (30%) SRs, 18/140 (13%) reported primary studies using an SES measure and 16/140 (11%) explicitly reported differential effects. 15/140 SRs (11%) explicitly focused on socioeconomic inequalities; of these 4/15 reported differential intervention effects in more detail, 7/15 concluded there was insufficient primary evidence to identify the impact of interventions on socioeconomic inequalities and 4/15 planned to examine differential effects by SES, but this was not reported further.

CONCLUSIONS

Our overview identifies that there is limited SR evidence on the equity impact of population-level interventions for adolescent health. Strengthening the evidence on whether interventions narrow or widen inequalities for adolescents must be a priority for public health research.

Abstract 151: Post-Partum Hypertension in Response to Acute Kidney Injury During Pregnancy

AKI during pregnancy is associated with high rates of maternal morbidity/mortality as well as fetal loss. Unfortunately women with HELLP (hemolysis, elevated liver, and low platelet) syndrome and preeclampsia are at an increased risk of developing AKI. For most women AKI during pregnancy resolves shortly after pregnancy and the effects have been thought to be temporary. However, new reports suggest that AKI during pregnancy can lead to progression of CKD. Using an established animal model of HELLP syndrome, the objective of the current study was to determine if AKI during pregnancy was associated with hypertension in the post-partum period. On gestational day (GD) 12, mini-osmotic pumps infusing sFlt-1 and sEng were placed into rats to induce HELLP (n=12). A subset of HELLP (n=7) and normal pregnant (NP; n=6) rats underwent bilateral renal ischemia-reperfusion surgery for 45 minutes on GD18. Untreated NP rats served as controls (n=9). All rats delivered on GD21 and were euthanized at post-partum week (PPW) 15. HELLP (6.2±0.08g; p=0.04), NP+AKI (5.3±0.09g; p<0.01) and HELLP+AKI (5.8±0.11g; p<0.01) rat pups were significantly smaller compared to NP rat pups (6.6±0.06g). Blood pressure was significantly increased in NP+AKI rats compared to NP rats (146±3.2 vs. 137±3.9mmHg; p=0.05) and in HELLP compared to NP rats (159±6.2mmHg; p=0.01) at PPW13. GFR was not increased in HELLP compared to NP (p=0.06) but was increased in NP+AKI rats (p=0.03) when measured at PPW14. Immune cells were examined via flow cytometry and NP+AKI had increased infiltrating renal CD4 + T cells compared to NP rats (11.2% vs. 3.4%; p=0.04). The ratio of M1/M2 macrophages in the kidneys of NP+AKI (19.2%; p=0.01) and HELLP (5.9%; p=0.05) was increased compared to NP rats (2.7%). Currently there are only 2 HELLP+AKI rats that survived to PPW13 (p=0.008) as 71.5% of the group died prior to post-partum day 5. The results from this study suggest that AKI during pregnancy contributes to progressive kidney injury and immune cell infiltration into the kidney. Additionally both NP+AKI and HELLP rats remained hypertensive 3 months post-partum. These results suggest that the cardiovascular and renal affects that occur during pregnancy can have a chronic affect and contribute to the worsening of maternal health.

Abstract P101: Interleukin 17 Signaling Mediates Cytolytic Natural Killer Cell Activation in Response to Placental Ischemia

The R educed U terine P erfusion P ressure (RUPP) rat model of placental ischemia mimics many characteristics of preeclampsia (PE) including hypertension, fetal growth restriction, and increased T H 17s, IL-17, and cytolytic natural killer cells (cNKs). IL-17 stimulates NK cytotoxicity in vitro . This study tested the hypothesis that blockade of IL-17 signaling would inhibit activation of cNKs to improve blood pressure and fetal growth in RUPP rats. On gestation day (GD) 14, osmotic pumps infusing IL-17 RC (100 pg/d), a soluble receptor for IL-17, were implanted into pregnant rats undergoing RUPP (RUPP+IL17 RC). On GD 19, circulating and placental T H 17s and cNKs were quantified via flow cytometry in normal pregnant (NP), RUPP, and RUPP+IL17 RC rats. cNK activation, placental ROS, fetal and placental weights, and MAP were also assessed. As we have previously shown, placental T H 17 populations (% gated) were significantly increased in RUPP (23.1±3.9%, n=9) compared to NP (8.5±3.9%, n=9) rats and were suppressed in RUPP+IL17 RC (8.3±3.1%, n=9). Circulating T H 17s followed the same trend. Placental cNKs, significantly increased from 7.2±2.8% in NP to 16.6±3.3% in RUPP, and were normalized to 7.2±2.8% after IL-17 blockade (p<0.05 vs RUPP). Placental cNK proteins and circulating cNKs showed a similar trend. Placental levels of the cNK cytokine, TNFα, increased from 28.5±.01 pg/mg in NP to 46.2±6.0 pg/mg in RUPP and was normalized to 28.5±4.6 pg/mg in RUPP+IL-17 RC (p<0.05 vs RUPP). Placental MIP3a, a cNK chemokine, had a similar trend. Assessment of in vitro cytotoxic activity of placental NK cells from rats in each group demonstrated a 5-fold increase in cytotoxicity by RUPP NK cells compared to NP NK cells. This was blunted in NK cells from RUPP+IL17 RC rats. Placental ROS was increased in RUPP compared to NP and significantly decreased with IL-17 blockade. Fetal weight decreased from 2.4±0.04 g in NP to 2.1±0.04 g in RUPP and increased to 2.3±0.05 g in RUPP+IL17 RC (p<0.05 vs RUPP). Placental weights followed a similar trend. MAP increased from 93 mmHg in NP to 120 mmHg in RUPP, and was decreased to 105 mmHg in RUPP+IL17 RC (p<0.05 vs RUPP). These data demonstrate a direct role for IL-17 signaling to mediate NK cytotoxic activation in response to placental ischemia during pregnancy.

Abstract 017: Cytolytic Natural Killer Cells Play a Direct Role in Causing Hypertension and Intrauterine Growth Restriction in Pregnant Rats

The R educed U terine P erfusion P ressure (RUPP) rat model of placental ischemia mirrors many of the hallmark features of preeclampsia (PE) such as hypertension, intrauterine growth restriction (IUGR), and immune activation, which includes increased cytolytic natural killer cells (cNKs). We have previously demonstrated that depletion of NK cells in RUPP rats improves PE pathophysiology. In this study we tested the hypothesis that RUPP-stimulated NKs have increased cytotoxicity and play a direct role in inflammation, oxidative stress, hypertension, and intrauterine growth restriction in pregnant rats. NK cells were isolated from the placentas of normal pregnant (NP) and RUPP rats on gestation day (GD) 19 and assessed for cytotoxic activity. RUPP NK cells demonstrated a 5-fold increase in cytotoxic activity vs NP NK cells. On GD 12, 5x10 6 NK cells from RUPP rats were infused into a subset of NP rats. On GD 19, circulating and placental total NK cells and cNKs were quantified via flow cytometry in NP, RUPP, and NP+RUPP NK rats. MAP, fetal and placental weights, placental reactive oxygen species (ROS), and placental cytokines were also measured. Placental cNK cells (%gated) were significantly increased in RUPP (18.5±3.6%) and NP+RUPP NK (16.1±3.6%) compared to NP (4.1±0.8%) controls. Circulating cNKs followed a similar trend. MAP increased from 100 mmHg in NP to 126 mmHg in RUPP, and 119 mmHg in NP+RUPP NK (p<0.05 vs NP). Fetal weight decreased from 2.4±0.03 g in NP to 2.0±0.04 g in RUPP and to 2.1±0.02 g in NP+RUPP NK (p<0.05 vs NP). Placental weights followed a similar trend. Placental cNK cytokines were significantly increased in RUPP and in NP recipients of RUPP NK cells: TNF-α: NP- 23±3.1, RUPP- 62.3±7.8 pg/mg, NP+RUPP NK-43.9±5.7 pg/mg (p<0.05 vs NP); IFNγ: NP- 3.3±0.7, RUPP- 7.6±1.2 pg/mg, NP+RUPP NK-6.6±1.9 pg/mg (p<0.05 vs NP). Placental VEGF decreased from 6.5±1.3 pg/mg in NP to 2±0.8pg/mg in RUPP and 2.9±0.6 pg/mg in NP+RUPP NK. Circulating levels followed a similar trend. Placental ROS significantly increased from 27.3±4.6 RLUs/min/mg in NP to 63.1±5.7 RLUs/min/mg in RUPP and 84±17.6 RLUs/min/mg in NP+RUPP NK. These data demonstrate a direct role for cNKs in causing PE pathophysiology and identifies cNKs as a novel therapeutic target for treatment of PE.

Knockout of Dual-Specificity Protein Phosphatase 5 Protects Against Hypertension-Induced Renal Injury

Dual-specificity protein phosphatase 5 (DUSP5) is a member of the tyrosine-threonine phosphatase family with the ability to dephosphorylate and inactivate extracellular signal-related kinase (ERK). The present study investigates whether knockout (KO) of Dusp5 improves renal hemodynamics and protects against hypertension-induced renal injury. The renal expression of DUSP5 was reduced, and the levels of phosphorylated (p) ERK1/2 and p-protein kinase C (PKC) α were elevated in the KO rats. KO of Dusp5 enhanced the myogenic tone of the renal afferent arteriole and interlobular artery in vitro with or without induction of deoxycorticosterone acetate-salt hypertension. Inhibition of ERK1/2 and PKC diminished the myogenic response to a greater extent in Dusp5 KO rats. Autoregulation of renal blood flow was significantly impaired in hypertensive wild-type (WT) rats but remained intact in Dusp5 KO animals. Proteinuria was markedly decreased in hypertensive KO versus WT rats. The degree of glomerular injury was reduced, and the expression of nephrin in the glomerulus was higher in hypertensive Dusp5 KO rats. Renal fibrosis and medullary protein cast formation were attenuated in hypertensive Dusp5 KO rats in association with decreased expression of monocyte chemoattractant protein 1, transforming growth factor-β1, matrix metalloproteinase (MMP) 2, and MMP9. These results indicate that KO of Dusp5 protects against hypertension-induced renal injury, at least in part, by maintaining the myogenic tone of the renal vasculature and extending the range of renal blood flow autoregulation to higher pressures, which diminish glomerular injury, protein cast formation, macrophage infiltration, and epithelial-mesenchymal transformation in the kidney. SIGNIFICANCE STATEMENT: Dual-specificity protein phosphatase 5 (DUSP5) is a tyrosine-threonine phosphatase that inactivates extracellular signal-related kinase (ERK). We previously reported that knockout (KO) of Dusp5 enhanced the myogenic response and autoregulation in the cerebral circulation. The present study investigates whether KO of DUSP5 improves renal hemodynamics and protects against hypertension-induced renal injury. Downregulation of DUSP5 enhanced the myogenic tone of renal arteriole and artery and autoregulation of renal blood flow in association with reduced proteinuria, glomerular injury, and interstitial fibrosis after the induction of hypertension. Inhibition of ERK1/2 and protein kinase C diminished the myogenic response to a greater extent in Dusp5 KO rats. These results suggest that DUSP5 might be a viable drug target for the treatment of hypertension nephropathy.

Chronic infusion of interleukin-17 promotes hypertension, activation of cytolytic natural killer cells, and vascular dysfunction in pregnant rats

Previous studies by our lab have established that placental-ischemia stimulated T-helper 17 cells (TH 17s) cause increased cytolytic natural killer (cNK) cell proliferation and activation during pregnancy; however, the exact mechanism is unknown. The objective of this study was to investigate the role of interlukin 17 (IL-17) in inducing cNK cell activation in pregnancy. We infused 150 pg/day of recombinant IL-17 into a subset of normal pregnant (NP) Sprague Dawley rats from gestation day (GD) 12-19 (NP+IL-17). On GD 19, mean arterial pressure (MAP), fetal and placental weights, cytokines, cNK cell activation, cytotoxic enzymes, and vascular reactivity were assessed. MAP significantly increased from 99 ± 3 mmHg in NP to 120 ± 1 mmHg in NP+IL-17 (P < 0.05). Fetal weight significantly decreased from 2.52 ± 0.04 g in NP to 2.32 ± 0.03 g in NP+IL-17 as did placental weight (NP: 0.65 ± 0.03 g; NP+IL-17: 0.54 ± 0.01 g, P < 0.05). Plasma levels of TNF-α increased to 281.4 ± 55.07 pg/mL in NP+IL-17 from 145.3 ± 16.03 pg/mL in NP (P < 0.05) while placental levels of VEGF decreased from 74.2 ± 6.48 pg/mg in NP to 54.2 ± 3.19 pg/mg in NP+IL-17. Total NK cells were increased in the placenta (NP: 14.3 ± 3.49%; NP+IL-17: 29.33 ± 2.76%, P < 0.05) as were cytolytic NK cells (NP: 3.31 ± 1.25%; NP+IL-17: 13.41 ± 1.81%, P < 0.05). A similar trend was observed in circulating NK cells. Plasma granzyme K increased from 3.55 ± 2.29 pg/mL in NP to 20.9 ± 7.76 pg/mL in NP+IL-17 (P < 0.05), and plasma granzyme B increased from 10.95 ± 0.64 pg/mL in NP to 14.9 ± 0.98 pg/mL in NP+IL-17(P < 0.05). In the placenta, both granzyme A (NP: 246.1 ± 16.7 pg/mg; NP+IL-17: 324.3 ± 15.07 pg/mg, P < 0.05) and granzyme B (NP: 15.18 ± 3.79 pg/mg; NP+IL-17: 27.25 ± 2.34 pg/mg, P < 0.05) increased in response to IL-17 infusion. Finally, vascular reactivity of uterine arteries was significantly impaired in response to IL-17 infusion. The results of this study suggest that IL-17 plays a significant role in the activation of cNK cells during pregnancy.

Impact of obesity as an independent risk factor for the development of renal injury: implications from rat models of obesity

Diabetes and hypertension are the major causes of chronic kidney disease (CKD). Epidemiological studies within the last few decades have revealed that obesity-associated renal disease is an emerging epidemic and that the increasing prevalence of obesity parallels the increased rate of CKD. This has led to the inclusion of obesity as an independent risk factor for CKD. A major complication when studying the relationship between obesity and renal injury is that cardiovascular and metabolic disorders that may result from obesity including hyperglycemia, hypertension, and dyslipidemia, or the cluster of these disorders [defined as the metabolic syndrome, (MetS)] also contribute to the development and progression of renal disease. The associations between hyperglycemia and hypertension with renal disease have been reported extensively in patients suffering from obesity. Currently, there are several obese rodent models (high-fat diet-induced obesity and leptin signaling dysfunction) that exhibit characteristics of MetS. However, the available obese rodent models currently have not been used to investigate the impact of obesity alone on the development of renal injury before hypertension and/or hyperglycemia. Therefore, the aim of this review is to describe the incidence and severity of renal disease in these rodent models of obesity and determine which models are suitable to study the independent effects obesity on the development and progression of renal disease.

Abstract P265: Early Renal Hyperfiltration In Obese Dahl Salt-Sensitive Leptin Receptor Mutant Rats is Associated With Glomerular Leukocyte Extravasation and Renal Disease

Hypertension and diabetes are the major causes of chronic kidney disease (CKD). However, epidemiological studies within the last few decades have revealed obesity as an independent risk factor for CKD. Recently, we reported that the obese Dahl salt-sensitive leptin receptor mutant (SS LepR mutant) strain displays proteinuria and podocyte injury by 6 weeks of age independent of hyperglycemia and elevations in arterial pressure. The current study examined whether the development of renal injury in the SS LepR mutant strain is associated with elevations in glomerular filtration rate (GFR). During the study, the SS LepR mutant strain developed hyperinsulinemia and dyslipidemia but not hyperglycemia. Baseline MAP (via carotid catheter) at 6 weeks of age was similar between SS WT (n=8) and SS LepR mutant (n=8) rats and averaged 124 mmHg. However, by 18 weeks of age, MAP increased significantly in the SS LepR mutant strain compared to the values measured in SS WT rats (192±4 vs 149±6 mmHg, respectively). At baseline, protein excretion was 4-fold higher in the SS LepR mutant strain compared to SS WT rats and remained elevated over the course of the study (778±96 vs 137±25 mg/day, respectively). At 6 weeks of age, GFR was 34% higher in the SS LepR mutant strain compared to age-matched SS WT rats indicating renal hyperfiltration (2.92±0.23 vs 2.18±0.25 mL/min/kwt, respectively). While we observed only a 40% reduction in GFR in SS WT rats (1.30±0.07 mL/min/kwt), GFR markedly decreased by 70% in the SS LepR mutant strain (0.87±0.08 mL/min/kwt). Over time, kidneys from the SS LepR mutant strain displayed more glomerulosclerosis, mesangial expansion, and renal fibrosis in comparison to SS WT rats. Glomeruli were isolated from the renal cortex of both strains at 6 and 18 weeks of age and RNA sequencing was performed to identify genes and pathways driving glomerular injury. The major, most consistent signaling pathways that changed at 6 and 18 weeks of age were involved in leukocyte extravasation. In conclusion, these data provide evidence that renal hyperfiltration may contribute to glomerular capillary leukocyte extravasation leading to the early development of proteinuria during obesity in the absence of hypertension and hyperglycemia.

Abstract 128: Interleukin-17 Mediates Hypertension, Intrauterine Growth Restriction, Cytolytic Natural Killer Cells and Vascular Dysfunction in Pregnant Rats

Preeclampsia is a hypertensive disorder of pregnancy characterized by intrauterine growth restriction (IUGR), vascular dysfunction, and chronic immune activation including increased T H 17s and cytolytic NK cells (NK C ). We recently developed a novel model of preeclampsia in which placental ischemia (PI)-induced T H 17s cause a preeclampsia-like phenotype in pregnant rats characterized by hypertension, IUGR, oxidative stress (ROS), and increased cytolytic NK cells (NK C ). In the current study we investigated a novel role for IL-17, the main cytokine secreted from T H 17s, to directly induce IUGR, NK C activation, and vascular dysfunction in pregnancy. IL-17 (150 pg/day) was chronically infused into a subset of normal pregnant (NP) rats from gestation day (GD) 12-19 (NP+IL-17) via i.p. minipump. On GD 18 carotid catheters were implanted and on GD 19 MAP, fetal weight, placental weight, placental NK C , and NK C -associated proteins were measured and vascular reactivity of uterine arteries was assessed. Data are expressed as mean±SEM. MAP significantly increased from 100±3 mmHg in NP (n=9) to 115±1 mmHg in NP+IL-17 (n=12). Fetal weight significantly decreased from 2.5±0.04 g in NP to 2.3±0.03 g in NP+IL-17 (p<0.05). Placental weight significantly decreased from 0.62±0.02 g in NP to 0.55±0.01 g in NP+IL-17 (p<0.05). Placental ROS significantly increased 1353±337 RLU/min/mg in NP to 2210±180 RLU/min/mg in NP+IL-17 (p<0.05). Placental NK C increased from 2.6±1.6% of the total NK population in NP to 11.3±2.2% in NP+IL-17 (p<0.05). Placental granzyme B increased from 22.7±1.6 pg/mg in NP to 30.2±2 pg/mg in NP+IL-17 (p<0.05). Placental granzyme A increased from 3067±225 pg/mg in NP to 3926±210 pg/mg (p<0.05). Additionally, placental levels of VEGF, an important pro-angiogenic factor secreted by non-cytolytic uterine NK cells significantly decreased from 77.6±6.5 pg/mg in NP to 54.2±3.2 pg/mg in NP+IL-17 (p<0.05). We also observed impaired relaxation of uterine arteries in response to acetylcholine. These data suggest a shift from non-cytolytic NK to NK C cells in the placentas of NP+IL17. In addition to hypertension and ROS, this study demonstrates novel roles for IL-17 to directly mediate IUGR, NK C activation, and endothelial vascular dysfunction during pregnancy.

Prevention of the progression of renal injury in diabetic rodent models with preexisting renal disease with chronic endothelin A receptor blockade

The endothelin (ET) system has emerged as a therapeutic target for the treatment of diabetic nephropathy (DN). The present study examined whether chronic endothelin A (ET_A) receptor blockade with atrasentan prevents the progression of renal injury in two models of DN with preexisting renal disease that exhibit an increased renal ET-1 system compared with nondiabetic rats: streptozotocin-treated Dahl salt-sensitive (STZ-SS) and type 2 diabetic nephropathy (T2DN) rats. Nine week-old SS rats were treated with (STZ; 50 mg/kg ip) to induce diabetes. After 3 wk of diabetes, proteinuria increased to 353 ± 34 mg/day. The rats were then separated into two groups: 1) vehicle and 2) atrasentan (5 mg·kg^-1·day^-1) via drinking water. After 6 wk of treatment with atrasentan, mean arterial pressure (MAP) and proteinuria decreased by 12 and 40%, respectively, in STZ-SS rats. The degree of glomerulosclerosis and renal fibrosis was significantly reduced in the kidneys of atrasentan-treated STZ-SS rats compared with vehicle STZ-SS rats. Interestingly, treatment with atrasentan did not affect GFR but significantly increased renal blood flow by 33% and prevented the elevations in filtration fraction and renal vascular resistance by 23 and 20%, respectively, in STZ-SS rats. In contrast to the STZ-SS study, atrasentan had no effect on MAP or proteinuria in T2DN rats. However, treatment with atrasentan significantly decreased glomerular injury and renal fibrosis and prevented the decline in renal function in T2DN rats. These data indicate that chronic ET_A blockade produces advantageous changes in renal hemodynamics that slow the progression of renal disease and also reduces renal histopathology in the absence of reducing arterial pressure and proteinuria.

Placental ischemia-stimulated T-helper 17 cells induce preeclampsia-associated cytolytic natural killer cells during pregnancy

Previous studies have demonstrated that T-helper 17 (T_H17) cells and cytolytic natural killer (cNK) cells are increased in women with preeclampsia. In this study we investigated the role of placental ischemia-stimulated T_H17 cells in induction of cNK cells in pregnancy. We further assessed the role of T_H17 cell-mediated oxidative stress in facilitation of cNK cell activation in pregnancy by treating rats with the SOD mimetic tempol. CD4⁺/CD25^- cells were isolated from reduced uterine perfusion pressure (RUPP) rats and differentiated into T_H17 cells in vitro. On day 12 of gestation ( GD12), 1 × 10⁶ placental ischemia-stimulated T_H17 cells were injected into normal pregnant (NP) rats (NP + RUPP T_H17 rats), and a subset of rats were treated with tempol (30 mg·kg^-1·day^-1) from GD12 to GD19 (NP + RUPP T_H17 + tempol rats). On GD19, cNK cells, mean arterial pressure, fetal weight, and cNK cell-associated cytokines and proteins were measured. Placental cNK cells were 2.9 ± 1, 14.9 ± 4, and 2.8 ± 1.0% gated in NP, NP + RUPP T_H17, and NP + RUPP T_H17 + tempol rats, respectively. Mean arterial pressure increased from 96 ± 5 mmHg in NP rats to 118 ± 2 mmHg in NP + RUPP T_H17 rats and was 102 ± 3 mmHg in NP + RUPP T_H17 + tempol rats. Fetal weight was 2.37 ± 0.04, 1.95 ± 0.14, and 2.3 ± 0.05 g in NP, NP + RUPP T_H17, and NP + RUPP T_H17 + tempol rats, respectively. Placental IFNγ increased from 1.1 ± 0.6 pg/mg in NP rats to 3.9 ± 0.6 pg/mg in NP + RUPP T_H17 rats. Placental perforin increased from 0.18 ± 0.18 pg/mg in NP rats to 2.4 ± 0.6 pg/mg in NP + RUPP T_H17 rats. Placental levels of granzymes A and B followed a similar pattern. Treatment with tempol did not lower placental cNK cytokines or proteins. The results of the present study identify T_H17 cells as a mediator of aberrant NK cell activation that is associated with preeclampsia.

AT1-AA (Angiotensin II Type 1 Receptor Agonistic Autoantibody) Blockade Prevents Preeclamptic Symptoms in Placental Ischemic Rats

Women with preeclampsia produce AT1-AA (agonistic autoantibodies to the angiotensin II type 1 receptor), which stimulate reactive oxygen species, inflammatory factors, and hypertensive mechanisms (ET [endothelin] and sFlt-1 [soluble fms-like tyrosine kinase-1]) in rodent models of preeclampsia. The placental ischemic reduced uterine perfusion pressure (RUPP) rat model of preeclampsia exhibits many of these features. In this study, we examined the maternal outcomes of AT1-AA inhibition ('n7AAc') in RUPP rats. Blood pressure was higher in RUPP rats versus normal pregnant (NP) rats (123±2 versus 99±2 mm Hg, P<0.05), which was reduced in RUPP+'n7AAc' (105±3 versus 123±2 mm Hg, P<0.05 versus RUPP). Uterine artery resistant index was increased in RUPP versus NP rats (0.71±0.02 versus 0.49±0.02, P<0.05) and normalized in RUPP+'n7AAc' rats (0.55±0.03). Antiangiogenic factor sFlt-1 was elevated in RUPP versus NP rats (176±37 versus 77±15 pg/mL, P<0.05) but normalized in RUPP+'n7AAc' (86±9, P=0.05 versus RUPP). Plasma nitrate and nitrite were decreased (14±1 versus 20±1 µMNO₃, P<0.05) and isoprostanes were elevated (20 117±6304 versus 2809±1375 pg/mL, P<0.05) in RUPP versus NP rats; and normalized in RUPP+'n7AAc' rats; (18±2 µMNO₃; 4311±1 pg/mL). PPET-1 (preproendothelin-1) expression increased 4-fold in RUPP versus NP rats which were prevented with 'n7AAc'. Importantly, placental cytolytic natural killer cells were elevated in RUPP versus NP rats (8±2% versus 2±2% gated, P<0.05), which was prevented in RUPP+'n7AAc' total (3±1% gated, P<0.05) In conclusion, AT1-AA inhibition prevents the rise in maternal blood pressure and several pathophysiological factors associated with preeclampsia in RUPP rats and could be a potential therapy for preeclampsia.

Abstract P551: Platelet Activation is Associated with Pulmonary Edema and Renal Injury in a Rat Model of Polymicrobial Sepsis

Sepsis, life-threatening organ dysfunction due to a dysregulated host response to infection, is positively correlated with platelet activation. Furthermore, clinical studies have also shown that platelet activation is associated with sepsis severity, suggesting a role for platelets in sepsis pathophysiology. Despite this correlation, the underlying mechanisms by which activated platelets contribute to sepsis are under investigated. In preliminary studies, we set out to determine if platelet activation is associated with multi-organ dysfunction and injury in a rat model of chronic polymicrobial abdominal sepsis. Sepsis was induced via cecal ligation and puncture (CLP) followed by cecum removal 24 hours post-CLP. At 72 hours post-CLP, blood, urine, and tissues were collected for analysis. Platelet activation was measured via flow cytometry. Lung wet/dry ratio and plasma creatinine were measured to assess lung edema and renal injury, respectively. Platelet activation doubled in CLP rats versus Sham rats. Activated platelets increased from 3.8±1.7% of the gated population in Sham animals (n=5) to 9.2±1.9% of the gated population in CLP animals (n=5; p=0.07). Lung wet/dry ratio significantly increased from 3.9±0.2 in Sham (n=8) to 6.7±1 in CLP rats (n=8; p<0.05). Furthermore, plasma creatinine increased by 33% from 0.55±0.3 mg/dL in Sham animals (n=6) to 0.73±0.06 mg/dL in CLP rats (n=8; p<0.05), indicating a decrease in renal function. These data demonstrate, for the first time, an increase in platelet activation in response to CLP, and identifies an association of activated platelets with pulmonary edema and reduced renal function in the cecal ligation and puncture rat model of abdominal polymicrobial sepsis. Future studies will investigate the underlying mechanisms by which activated platelets contribute to multi-organ dysfunction and injury in sepsis.

Synergistic Interaction of Hypertension and Diabetes in Promoting Kidney Injury and the Role of Endoplasmic Reticulum Stress

Diabetes mellitus and hypertension are major risk factors for chronic kidney injury, together accounting for >70% of end-stage renal disease. In this study, we assessed interactions of hypertension and diabetes mellitus in causing kidney dysfunction and injury and the role of endoplasmic reticulum (ER) stress. Hypertension was induced by aorta constriction (AC) between the renal arteries in 6-month-old male Goto-Kakizaki (GK) type 2 diabetic and control Wistar rats. Fasting plasma glucose averaged 162±11 and 87±2 mg/dL in GK and Wistar rats, respectively. AC produced hypertension in the right kidney (above AC) and near normal blood pressure in the left kidney (below AC), with both kidneys exposed to the same levels of glucose, circulating hormones, and neural influences. After 8 weeks of AC, blood pressure above the AC (and in the right kidney) increased from 109±1 to 152±5 mm Hg in GK rats and from 106±4 to 141±5 mm Hg in Wistar rats. The diabetic-hypertensive right kidneys in GK-AC rats had much greater increases in albumin excretion and histological injury compared with left kidneys (diabetes mellitus only) of GK rats or right kidneys (hypertension only) of Wistar-AC rats. Marked increases in ER stress and oxidative stress indicators were observed in diabetic-hypertensive kidneys of GK-AC rats. Inhibition of ER stress with tauroursodeoxycholic acid for 6 weeks reduced blood pressure (135±4 versus 151±4 mm Hg), albumin excretion, ER and oxidative stress, and glomerular injury, while increasing glomerular filtration rate in hypertensive-diabetic kidneys. These results suggest that diabetes mellitus and hypertension interact synergistically to promote kidney dysfunction and injury via ER stress.

Children and young people's conceptualizations of depression: a systematic review and narrative meta-synthesis

BACKGROUND

There is an increasing research interest in conceptualizations of mental illness, examined in association with help-seeking, stigma and treatment preferences. A recent focus on young people's concepts has been identified, with depression being one of the most examined conditions.

METHODS

The purpose of this systematic review is to synthesize evidence on children and adolescents' conceptualizations of depression, adopting the model of illness representations. The review further aims to examine developmental trends, gender differences and the role of experience. A systematic review and narrative meta-synthesis were conducted, reviewing 36 studies identified through a systematic search of six databases in March 2016.

RESULTS

Thirty-six quantitative and qualitative studies were included. Half of the young people are able to recognize depression, and recognition increases when symptoms are more severe (e.g. suicidality). Young people are able to name a variety of causes for depression. Mental health professionals are considered the appropriate source of help by half of the young people, followed by family and peers. However, stigma constitutes a major barrier to help-seeking. There are developmental trends and gender differences in young people's conceptualization of depression, while experience with depression is associated with a broader conceptualization.

CONCLUSIONS

Young people's concepts of depression resemble aspects of adult conceptualizations, however are sometimes incomplete. Further research on younger children and clinical populations is needed. Research on young people's conceptualizations informs both clinical practice and mental health literacy interventions.