IL-33 supplementation improves uterine artery resistance and maternal hypertension in response to placental ischemia

Preeclampsia (PE), a leading cause of maternal/fetal morbidity and mortality, is a hypertensive pregnancy disorder with end-organ damage that manifests after 20 wk of gestation. PE is characterized by chronic immune activation and endothelial dysfunction. Clinical studies report reduced IL-33 signaling in PE. We use the Reduced Uterine Perfusion Pressure (RUPP) rat model, which mimics many PE characteristics including reduced IL-33, to identify mechanisms mediating PE pathophysiology. We hypothesized that IL-33 supplementation would improve blood pressure (BP), inflammation, and oxidative stress (ROS) during placental ischemia. We implanted intraperitoneal mini-osmotic pumps infusing recombinant rat IL-33 (1 µg/kg/day) into normal pregnant (NP) and RUPP rats from gestation day 14 to 19. We found that IL-33 supplementation in RUPP rats reduces maternal blood pressure and improves the uterine artery resistance index (UARI). In addition to physiological improvements, we found decreased circulating and placental cytolytic Natural Killer cells (cNKs) and decreased circulating, placental, and renal TH17s in IL-33-treated RUPP rats. cNK cell cytotoxic activity also decreased in IL-33-supplemented RUPP rats. Furthermore, renal ROS and placental preproendothelin-1 (PPET-1) decreased in RUPP rats treated with IL-33. These findings demonstrate a role for IL-33 in controlling vascular function and maternal BP during pregnancy by decreasing inflammation, renal ROS, and PPET-1 expression. These data suggest that IL-33 may have therapeutic potential in managing PE.NEW & NOTEWORTHY Though decreased IL-33 signaling has been clinically associated with PE, the mechanisms linking this signaling pathway to overall disease pathophysiology are not well understood. This study provides compelling evidence that mechanistically links reduced IL-33 with the inflammatory response and vascular dysfunction observed in response to placental ischemia, such as in PE. Data presented in this study submit the IL-33 signaling pathway as a possible therapeutic target for the treatment of PE.

Inhibition of Caspase 1 Reduces Blood Pressure, Cytotoxic NK Cells, and Inflammatory T-Helper 17 Cells in Placental Ischemic Rats

Preeclampsia (PE) is characterized by maternal hypertension, fetal growth restriction (FGR), and increased inflammation and populations of cytotoxic NK cells (cNKs) and inflammatory T-Helper 17 cells (TH17s). Both cytotoxic NK cells and TH17 cells are heavily influenced via IL-1β signaling. Caspase 1 activity leads to the release of the inflammatory cytokine IL-1β, which is increased in women with PE. Therefore, we tested the hypothesis that the inhibition of Caspase 1 with VX-765 in rats with reduced uterine perfusion pressure (RUPP) will attenuate PE pathophysiology. On gestation day (GD) 14, timed pregnant Sprague-Dawley rats underwent the RUPP or Sham procedure and were separated into groups that received either vehicle or VX-765 (50 mg/kg/day i.p.). On GD19, MAP was measured via carotid catheter and blood and tissues were collected. Bio-Plex and flow cytometry analysis were performed on placental tissues. Placental IL-1β was increased in the RUPP rats vs. the Sham rats and treatment with VX-765 reduced IL-1β in the RUPP rats. Caspase 1 inhibition reduced placental cNKs and TH17s in RUPP rats compared to vehicle-treated RUPP rats. Increased MAP was observed in RUPP rats compared with Sham rats and was reduced in RUPP + VX-765 rats. Placental reactive oxygen species (ROS) were elevated in RUPP rats compared to Sham rats. VX-765 administration reduced ROS in treated RUPP rats. Caspase 1 inhibition increased the number of live pups, yet had no effect on fetal weight or placental efficiency in the treated groups. In conclusion, Caspase 1 inhibition reduces placental IL-1β, inflammatory TH17 and cNK populations, and reduces MAP in RUPP rats. These data suggest that Caspase 1 is a key contributor to PE pathophysiology. This warrants further investigation of Caspase 1 as a potential therapeutic target to improve maternal outcomes in PE.

Metformin reduces insulin resistance and attenuates progressive renal injury in prepubertal obese Dahl salt-sensitive rats

Prepubertal obesity is currently an epidemic and is considered as a major risk factor for renal injury. Previous studies have demonstrated that insulin resistance contributes to renal injury in obesity, independent of diabetes. However, studies examining the relationship between insulin resistance and renal injury in obese children are lacking. Recently, we reported that progressive renal injury in Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) rats was associated with insulin resistance before puberty. Therefore, the aim of the present study was to examine whether decreasing insulin resistance with metformin will reduce renal injury in SSLepRmutant rats. Four-wk-old SS and SSLepRmutant rats were separated into the following two groups: 1) vehicle and 2) metformin (300 mg/kg/day) via chow diet for 4 wk. Chronic administration of metformin markedly reduced insulin resistance and dyslipidemia in SSLepRmutant rats. We did not detect any differences in mean arterial pressure between vehicle and metformin-treated SS and SSLepRmutant rats. Proteinuria was significantly greater in SSLepRmutant rats versus SS rats throughout the study, and metformin administration significantly reduced proteinuria in SSLepRmutant rats. At the end of the protocol, metformin prevented the renal hyperfiltration observed in SSLepRmutant rats versus SS rats. Glomerular and tubular injury and renal inflammation and fibrosis were significantly higher in vehicle-treated SSLepRmutant rats versus SS rats, and metformin reduced these parameters in SSLepRmutant rats. These data suggest that reducing insulin resistance with metformin prevents renal hyperfiltration and progressive renal injury in SSLepRmutant rats before puberty and may be therapeutically useful in managing renal injury during prepubertal obesity.NEW & NOTEWORTHY Childhood/prepubertal obesity is a public health concern that is associated with early signs of proteinuria. Insulin resistance has been described in obese children. However, studies investigating the role of insulin resistance during childhood obesity-associated renal injury are limited. This study provides evidence of an early relationship between insulin resistance and renal injury in a rat model of prepubertal obesity. These data also suggest that reducing insulin resistance with metformin may be renoprotective in obese children.

Chronic treatment with IL-25 increases renal M2 macrophages and reduces renal injury in obese Dahl salt-sensitive rats during the prepubescent stage

Recently, we have reported that the early progression of proteinuria in the obese Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) strain was associated with increased renal macrophage infiltration before puberty. Macrophages can be divided into two distinct phenotypes: M1 (proinflammatory) and M2 (anti-inflammatory). Moreover, previous studies have demonstrated that interleukin (IL)-25 converts resting macrophages and M1 into M2. Therefore, the present study examined whether treatment with IL-25 would reduce the early progression of renal injury in SSLepRmutant rats by increasing renal M2. We also investigated the impact of IL-25 on M2 subtypes: M2a (wound healing/anti-inflammatory), M2b (immune mediated/proinflammatory), M2c (regulatory/anti-inflammatory), and M2d (tumor associated/proangiogenic). Four-wk-old SS and SSLepRmutant rats were treated with either control (IgG) or IL-25 (1 µg/day ip every other day) for 4 wk. The kidneys from SSLepRmutant rats displayed progressive proteinuria and renal histopathology versus SS rats. IL-25 treatment had no effect on these parameters in SS rats. However, in the SSLepRmutant strain, proteinuria was markedly reduced after IL-25 treatment. Chronic treatment with IL-25 significantly decreased glomerular and tubular injury and renal fibrosis in the SSLepRmutant strain. Although the administration of IL-25 did not change total renal macrophage infiltration in both SS and SSLepRmutant rats, IL-25 increased M2a by >50% and reduced M1 by 60% in the kidneys of SSLepRmutant rats. Overall, these data indicate that IL-25 reduces the early progression of renal injury in SSLepRmutant rats by inducing M2a and suppressing M1 and suggest that IL-25 may be a therapeutic target for renal disease associated with obesity. NEW & NOTEWORTHY For the past few decades, immune cells and inflammatory cytokines have been demonstrated to play an important role in the development of renal disease. The present study provides strong evidence that interleukin-25 slows the early progression of renal injury in obese Dahl salt-sensitive rats before puberty by increasing systemic anti-inflammatory cytokines and renal M2a macrophages.

NLRP3 inhibition improves maternal hypertension, inflammation, and vascular dysfunction in response to placental ischemia

Preeclampsia (PE) is a pregnancy-specific hypertensive disorder with end-organ damage that presents after 20 wk of gestation. PE pathophysiology often includes vascular dysfunction and increased inflammation that continues to damage patient health even after PE resolves. Currently, there is no cure for PE beyond delivery of the fetal-placental unit. Previous clinical studies have identified elevated placental NLRP3 expression in patients with PE and suggest NLRP3 as a potential therapeutic target. In this study, we examined the effect of NLRP3 inhibition on PE pathophysiology in the reduced uterine perfusion pressure (RUPP) model rat using MCC950 (20 mg/kg/day) or esomeprazole (3.5 mg/kg/day). We hypothesized that increased NLRP3 in response to placental ischemia impairs anti-inflammatory IL-33 signaling to induce T-helper 17 cell (TH17) and cytolytic NK cell (cNK) activation, which is known to mediate oxidative stress and vascular dysfunction leading to maternal HTN and intrauterine growth restriction. RUPP rats had significantly higher placental NLRP3 expression, maternal blood pressure, fetal reabsorption rate, vascular resistance, oxidative stress, cNKs and TH17s, and decreased IL-33 compared with normal pregnant (NP) rats. NLRP3 inhibition, with either treatment, significantly reduced placental NLRP3 expression, maternal blood pressure, fetal reabsorption rates, vascular resistance, oxidative stress, cNK, and TH17 populations in RUPP rats. Based on our findings, NLRP3 inhibition reduces PE pathophysiology and esomeprazole may be a potential therapeutic for PE treatment.

Neutralizing MIP3α Reduces Renal Immune Cell Infiltration and Progressive Renal Injury in Young Obese Dahl Salt-Sensitive Rats

Recently, we reported that the early progression of renal injury in obese Dahl salt-sensitive leptin receptor mutant (SSLepRmutant) rats was associated with increased macrophage inflammatory protein 3-α (MIP3α) expression prior to puberty. Therefore, this study tested the hypothesis that MIP3α plays a role in recruiting immune cells, thereby triggering renal inflammation and early progressive renal injury in SSLepRmutant rats prior to puberty. Four-week-old Dahl salt-sensitive (SS) and SSLepRmutant rats either served as control (IgG; intraperitoneal, every other day) or received MIP3α-neutralizing antibody (MNA; 100 µg/kg) for 4 weeks. MNA reduced circulating and renal MIP3α levels and proinflammatory immune cells by 50%. Although MNA treatment did not affect blood glucose and plasma cholesterol levels, MNA markedly decreased insulin resistance and triglyceride levels in SSLepRmutant rats. We observed no differences in mean arterial pressure (MAP) between SS and SSLepRmutant rats, and MNA had no effect on MAP in either strain. Proteinuria was significantly increased in SSLepRmutant rats versus SS rats over the course of the study. Treatment with MNA markedly decreased proteinuria in SSLepRmutant rats while not affecting SS rats. Also, MNA decreased glomerular and tubular injury and renal fibrosis in SSLepRmutant rats while not affecting SS rats. Overall, these data indicate that MIP3α plays an important role in renal inflammation during the early progression of renal injury in obese SSLepRmutant rats prior to puberty. These data also suggest that MIP3α may be a novel therapeutic target to inhibit insulin resistance and prevent progressive proteinuria in obese children. SIGNIFICANCE STATEMENT: Childhood obesity is increasing at an alarming rate and is now being associated with renal disease. Although most studies have focused on the mechanisms of renal injury associated with adult obesity, few studies have examined the mechanisms of renal injury involved during childhood obesity. In the current study, we observed that the progression of renal injury in obese Dahl salt-sensitive leptin receptor mutant rats was associated with an increase in MIP3α, a chemokine, before puberty, and inhibition of MIP3α markedly reduced renal injury.

Renoprotective effects of empagliflozin in type 1 and type 2 models of diabetic nephropathy superimposed with hypertension

Diabetes, hypertension, and aging are major contributors to cardiovascular and chronic kidney disease (CKD). Sodium/glucose cotransporter 2 (SGLT2) inhibitors have become a preferred treatment for type II diabetic patients since they have cardiorenal protective effects. However, most elderly diabetic patients also have hypertension, and the effects of SGLT2 inhibitors have not been studied in hypertensive diabetic patients or animal models. The present study examined if controlling hyperglycemia with empagliflozin, or given in combination with lisinopril, slows the progression of renal injury in hypertensive diabetic rats. Studies were performed using hypertensive streptozotocin-induced type 1 diabetic Dahl salt-sensitive (STZ-SS) rats and in deoxycorticosterone-salt hypertensive type 2 diabetic nephropathy (T2DN) rats. Administration of empagliflozin alone or in combination with lisinopril reduced blood glucose, proteinuria, glomerular injury, and renal fibrosis in STZ-SS rats without altering renal blood flow (RBF) or glomerular filtration rate (GFR). Blood pressure and renal hypertrophy were also reduced in rats treated with empagliflozin and lisinopril. Administration of empagliflozin alone or in combination with lisinopril lowered blood glucose, glomerulosclerosis, and renal fibrosis but had no effect on blood pressure, kidney weight, or proteinuria in hypertensive T2DN rats. RBF was not altered in any of the treatment groups, and GFR was elevated in empagliflozin-treated hypertensive T2DN rats. These results indicate that empagliflozin is highly effective in controlling blood glucose levels and slows the progression of renal injury in both hypertensive type 1 and type 2 diabetic rats, especially when given in combination with lisinopril to lower blood pressure.

Abstract 014: Gestational Diabetic Cd4+ T Cells Cause Increased Glucose, Blood Pressure And Placental Mitochondrial Dysfunction In A Novel Rat Model Of Diabetes During Pregnancy

Hypertensive (HTN) disorders complicate ~10% of all pregnancies worldwide and contribute to maternal and fetal morbidity and mortality. HTN increases risks for preeclampsia and preterm labor in women with gestational diabetes mellitus (GDM) and is characterized by hyperglycemia resulting from defects in insulin activity/secretion or both. Also, increased levels of maternal glucose, inflammatory mediators, abnormal placental vascular function, and cytokines are associated with the pathogenesis of GDM, however, we don’t know the importance of placental factors, inflammatory cells, and cytokines in causing HTN or other pathophysiological factors associated with GDM. We hypothesize placental CD4+T cells from pregnant DM patients (GDM) causes a DM phenotype in pregnant athymic nude rats. CD4+T cells were magnetically separated from placentas from GDM patients and injected into athymic nude rats on Gestation Day (GD) 12. On GD19, blood pressure (MAP), blood and tissues were collected and glucose was measured from GDM CD4+T cell recipients and pregnant nude control rats.Mitochondrial respiration and mtROS were measured as indicators of tissue function from isolated placental mitochondria using the Oxygraph 2K and fluorescent microplate reader, respectively. A student’s t-test was used for statistical analysis. On GD19, MAP increased to 117±5.3 mmHg (n=3) in GDM T cell recipients compared to control pregnant athymic nude rats 102±0.0 mmHg (n=5). Blood glucose levels were elevated with GDM CD4+ T cells (275 ± 80 mg/dl, n=3, p<0.05) compared to pregnant athymic nude rats (91 ± 16 mg/dl, n=5).Placental state 3 (10±1 vs 433±113 pmol/sec/mg, p<0.05), indicative of ATP production, was reduced with GDM CD4+ T cells (n=3) compared to control pregnant athymic nude rats(n=5). Placental mtROS (H2O2) was increased with GDM CD4+ T cells (264 ± 14 % gated, n=3, p<0.05) compared to pregnant athymic nude rats (100 ± 26 % gated, n=5).Collectively, these data indicate that GDM CD4+T cells cause the GDM phenotype during pregnancy by increasing glucose and blood pressure in association with placental mitochondrial dysfunction/ROS during pregnancy, thereby introducing a new model to investigate mechanisms and new therapies for diabetes during pregnancy.

Abstract 103: Il-33 Supplementation Improves Vascular Function And Maternal Hypertension In Response To Placental Ischemia

Preeclampsia (PE), a leading cause of maternal and fetal morbidity and mortality, is a hypertensive pregnancy disorder with end-organ damage that develops after 20 weeks of gestation. PE is characterized by chronic immune activation, endothelial dysfunction, and fetal growth restriction (FGR). Clinical studies have shown decreased IL-33 signaling in PE women. We use the Reduced Uterine Perfusion Pressure (RUPP) rat model, which mimics many characteristics of PE patients including reduced IL-33 levels, to identify the mechanisms mediating maternal hypertension and FGR in PE. We hypothesized that IL-33 supplementation would improve maternal hypertension, fetal growth, and oxidative stress (ROS) during placental ischemia in pregnant rats. We implanted intraperitoneal mini-osmotic pumps infusing recombinant rat IL-33 (1 μg/kg/day) in normal pregnant (NP) and RUPP rats from gestation day 14-19. Maternal blood pressure, fetal growth, placental and renal ROS, phosphorylated endothelial nitric-oxide synthase ( p eNOS), and uterine artery resistance index (UARI) were assessed. MAP (mmHg) increased from 104±4 in NP to 124±7 in RUPP (p<0.05) and was significantly lowered in RUPP+IL-33 to 108±10 (p<0.05, n=6-8/group). Fetal weight was significantly increased in RUPP+ IL-33 compared to RUPP (p<0.05). Placental ROS was not different among any groups. However, renal ROS (relative light units/min/mg protein) was increased from 452±33 in NP to 676±44 in RUPP (p<0.05) and was significantly decreased to 309±61 in RUPP+IL-33 (n=4-5/group, p<0.05 vs RUPP). Placental p eNOS expression was 4-fold lower in RUPP vs NP (p<0.05) and 5-fold lower in RUPP+IL-33 vs NP, n=3-5/group). UARI (arbitrary units) was 0.709±0.012 in RUPP vs NP (0.585±0.025, p<0.05) and was significantly lowered to 0.577±0.025 in RUPP+IL-33 rats (p<0.05 vs RUPP, n=5-6/group). These findings demonstrate a role for IL-33 in controlling vascular function and maternal blood pressure during pregnancy independent of eNOS activation. Further studies will quantify effector immune cells and inflammatory cytokine levels in response to IL-33 supplementation during placental ischemia. These data suggest that IL-33 may have therapeutic potential in management of PE pathophysiology during pregnancy.

The SSLepR mutant rat represents a novel model to study obesity-induced renal injury before puberty

Prepubertal obesity (PPO) has emerged as a major health problem over the past few decades and is a risk factor for the development of proteinuria. The current study investigated whether the development of renal injury in the obese SSLepR mutant strain occurs before puberty. When determining the temporal changes in serum sex hormones in female and male SS and SSLepR mutant rats between 4 and 10 wk of age, we only observed significant increases in estradiol and testosterone levels in female and male SS rats at 10 wk of age than at 4 wk of age. The results suggest that studying both strains between 4 and 8 wk of age is appropriate to study the effects of PPO on renal injury in this model. Proteinuria was significantly higher in SSLepR mutant rats as opposed to the values observed in SS rats at 8 wk of age, and we did not observe any sex differences in proteinuria in either strain. The kidneys from the SSLepR mutant rats displayed significant glomerular and tubular injury and renal fibrosis versus the values measured in SS rats without any sex differences. Overall, we observed increased immune cell infiltration in the kidneys from SSLepR mutant rats compared with SS rats. Interestingly, female SSLepR mutant rats displayed significant increases in not only M1 macrophages (proinflammatory) but also M2 macrophages (anti-inflammatory) versus male SSLepR mutant rats. These results suggest the SSLepR mutant rat may be a useful model to study early progression of obesity-related renal injury before the onset of puberty.

Treatment With Lisinopril Prevents the Early Progression of Glomerular Injury in Obese Dahl Salt-Sensitive Rats Independent of Lowering Arterial Pressure

Recently, we reported that obese Dahl salt-sensitive leptin receptor mutant (SSLepRmutant) rats develop glomerular injury and progressive proteinuria prior to puberty. Moreover, this early progression of proteinuria was associated with elevations in GFR. Therefore, the current study examined whether treatment with lisinopril to reduce GFR slows the early progression of proteinuria in SSLepRmutant rats prior to puberty. Experiments were performed on 4-week-old SS and SSLepRmutant rats that were either treated with vehicle or lisinopril (20 mg/kg/day, drinking water) for 4 weeks. We did not observe any differences in MAP between SS and SSLepRmutant rats treated with vehicle (148 ± 5 vs. 163 ± 6 mmHg, respectively). Interestingly, chronic treatment with lisinopril markedly reduced MAP in SS rats (111 ± 3 mmHg) but had no effect on MAP in SSLepRmutant rats (155 ± 4 mmHg). Treatment with lisinopril significantly reduced proteinuria in SS and SSLepRmutant rats compared to their vehicle counterparts (19 ± 5 and 258 ± 34 vs. 71 ± 12 and 498 ± 66 mg/day, respectively). Additionally, nephrin excretion was significantly elevated in SSLepRmutant rats versus SS rats, and lisinopril reduced nephrin excretion in both strains. GFR was significantly elevated in SSLepRmutant rats compared to SS rats, and lisinopril treatment reduced GFR in SSLepRmutant rats by 30%. The kidneys from SSLepRmutant rats displayed glomerular injury with increased mesangial expansion and renal inflammation versus SS rats. Chronic treatment with lisinopril significantly decreased glomerular injury and renal inflammation in the SSLepRmutant rats. Overall, these data indicate that inhibiting renal hyperfiltration associated with obesity is beneficial in slowing the early development of glomerular injury and renal inflammation.

Abstract 42: Inhibiting Stimulatory Dendritic Cells Reduces Early Progressive Proteinuria In Obese Dahl Salt-sensitive Rats

Childhood/prepubertal (PPO) obesity has emerged as an epidemic and major health problem over the last few decades and is a risk factor for the development of proteinuria. With the rising prevalence of obesity in children, studies examining how obesity contributes to the early development of proteinuria and renal injury in children are lacking. Recently, we observed that the early progression of proteinuria in the obese SS LepR mutant rats was associated with the increased renal infiltration of stimulatory dendritic cells (sDCs). Previous studies have demonstrated that sDCs interact with and activate T-cells to elicit a pro-inflammatory response. Therefore, the current study examined whether chronic treatment with abatacept will reduce proteinuria in SS LepR mutant rats prior to puberty by interfering with sDC-T-cell crosstalk. Four-week-old SS and SS LepR mutant rats were treated with either vehicle (PBS) or abatacept (1 mg/kg, i.p. every alternate day) for 4 weeks. We observed no significant differences in blood glucose levels and mean arterial pressure between vehicle- and abatacept-treated SS and SS LepR mutant rats. While proteinuria only rose from 9±3 to 48±28 mg/day in SS rats, proteinuria markedly increased from 40±13 to 638±73 mg/day in SS LepR mutant rats. Chronic treatment with abatacept significantly decreased the progression of proteinuria by almost 50% in SS LepR mutant rats (350±15 mg/day; p<0.05 vs. vehicle-treated SS LepR mutant rats) without having any effect in SS rats (29±11 mg/day). We observed a significant increase in the renal infiltration of sDCs and cytotoxic T-cells in SS LepR mutant rats in comparison to their lean SS counterparts, and chronic treatment with abatacept reduced the infiltration of sDCs and cytotoxic T-cells only in the SS LepR mutant rats. These data indicate that targeting sDC/T-cell interaction pathways could offer novel therapeutic insights in the early management of proteinuria and renal injury associated with PPO.

Abstract 31: Esomeprazole Improves Blood Pressure, Intrauterine Growth, Inflammation, And Vascular Function During Placental Ischemia Through Inhibition Of NLRP3

Preeclampsia (PE), a multisystem hypertensive disorder of pregnancy is characterized by intrauterine growth restriction (IUGR), inflammation, and vascular dysfunction. NLRP3 inflammasome is a cytoplasmic complex that mediates inflammation and is implicated in CVD. Clinical studies show an association between PE and increased placental NLRP3 expression. We hypothesized that inhibition of NLRP3 using (1) a specific NLRP3 small molecule inhibitor, MCC950 (M9, 20 mg/kg/d, i.p.) or (2) esomeprazole (ESO, 3.5 mg/kg/d, oral), a therapeutic that is safe in pregnancy, would improve MAP, inflammation, IUGR, and vascular dysfunction in the reduced uterine perfusion pressure (RUPP) rat model of placental ischemia. Sham (S) or RUPP surgery was performed in pregnant Sprague Dawley rats on gestation day (GD) 14. A subset of rats from both groups received either vehicle, M9, or ESO on GD14-19 (n=9/group). On GD18, Uterine Artery Resistance Index (UARI) was measured via Doppler Ultrasound. MAP, fetal, and placental weight were measured, and blood and tissues were processed for additional analyses on GD19. MAP (mmHg) was elevated in RUPP (133±1) vs S (108±2; p<0.05). Treatment with M9 or ESO in RUPP decreased MAP (111±1 and 115±3, respectively; p<0.05 vs RUPP). Fetal weight (g) was reduced in RUPP (2.1±0.04) vs S (2.4±0.05), and ESO normalized fetal weight (2.4±0.01; p<0.05 vs RUPP). Placental NLRP3 mRNA expression increased 5-fold in RUPP vs S (p<0.05); and was less than 2 fold in M9 and ESO treated RUPP rats (p<0.05 vs RUPP). Inflammatory T-helper 17 and cytolytic NK cells, evaluated by flow cytometry, were increased in the circulation, placenta, and kidney of RUPP vs S controls. Treatment with M9 or ESO normalized both cell populations in all tissues (p<0.05 vs RUPP). UARI was increased in RUPP (0.71±0.03) versus S (0.56±0.01; p<0.05) and was decreased to 0.48±0.01 in M9 and 0.61±0.03 in ESO-treated RUPPs (p<0.05 vs RUPP). Renal vascular resistance (mmHg/mL/min/g) was increased in RUPP (42±8) vs S (23±4, p<0.05) and was normalized to 26±3 after treatment with M9 (p<0.05 vs RUPP). These data implicate NLRP3 in mediating inflammation and vascular dysfunction to cause maternal HTN and IUGR in RUPP; and identify NLRP3 as a potential target and ESO as a potential therapeutic for PE.

Adoptive transfer of placental ischemia-stimulated natural killer cells causes a preeclampsia-like phenotype in pregnant rats

PROBLEM

The Reduced Uterine Perfusion Pressure (RUPP) rat model of placental ischemia recapitulates many characteristics of preeclampsia including maternal hypertension, intrauterine growth restriction (IUGR), and increased cytolytic natural killer cells (cNKs). While we have previously shown a 5-fold higher cytotoxicity of RUPP NKs versus normal pregnant NKs, their role in RUPP pathophysiology remains unclear. In this study, we tested the hypotheses that (1) adoptive transfer of RUPP-stimulated NKs will induce maternal hypertension and IUGR in normal pregnant control (Sham) rats and (2) adoptive transfer of Sham NKs will attenuate maternal hypertension and IUGR in RUPP rats.

METHOD OF STUDY

On gestation day (GD)14, vehicle or 5 × 106 RUPP NKs were infused i.v. into a subset of Sham rats (Sham+RUPP NK), and vehicle or 5 × 106 Sham NKs were infused i.v. into a subset of RUPP rats (RUPP+Sham NK; n = 12/group). On GD18, Uterine Artery Resistance Index (UARI) was measured. On GD19, mean arterial pressure (MAP) was measured, animals were sacrificed, and blood and tissues were collected for analysis.

RESULTS

Adoptive transfer of RUPP NKs into Sham rats resulted in elevated NK activation, UARI, placental oxidative stress, and preproendothelin expression as well as reduced circulating nitrate/nitrite. This led to maternal hypertension and IUGR. RUPP recipients of Sham NKs demonstrated normalized NK activation, sFlt-1, circulating and placental VEGF, and UARI, which led to improved maternal blood pressure and normal fetal growth.

CONCLUSION

These data suggest a direct role for cNKs in causing preeclampsia pathophysiology and a role for normal NKs to improve maternal outcomes and IUGR during late gestation.

Establishing consensus on the best ways to educate children about animal welfare and prevent harm: An online Delphi study

Many animal welfare organisations deliver education programmes for children and young people, or design materials for schoolteachers to use. However, few of these are scientifically evaluated, making it difficult for those working in this field to establish with any certainty the degree of success of their own programmes, or learn from others. There has been no guidance specifically tailored to the development and evaluation of animal welfare education interventions. Accordingly, a three-stage online Delphi study was designed to unearth the expertise of professionals working in this field and identify degree of consensus on various aspects of the intervention process: design, implementation and evaluation. Thirty-one experts participated in Round 1, representing eleven of 13 organisations in the Scottish Animal Welfare Education Forum (SAWEF), and eleven of 23 members of the wider UK-based Animal Welfare Education Alliance (AWEA). Seven further professionals participated, including four based in Canada or the US. Eighty-four percent of the original sample participated in Round 2, where a high level of consensus was apparent. However, the study also revealed areas of ambiguity (determining priorities, the need for intervention structure and degree of success). Tensions were also evident with respect to terminology (especially around cruelty and cruelty prevention), and the common goal for animal welfare to be part of school curricula. Findings were used to develop a web-based framework and toolkit to enable practitioners to follow evidence-based guidance. This should enable organisations to maximise the quality and effectiveness of their interventions for children and young people.

The challenges and future development of animal welfare education in the UK

At present, UK schools are not required to teach children about animal welfare. This undoubtedly contributes to widespread deficien- cies in knowledge, and misconceptions about animals needs, likes, and dislikes. Aware of the issues at hand, animal welfare organi- sations create their own materials for teachers to use, and/or deliver educational programmes directly to children and young people. As the design, content, processes and outcomes associated with these interventions are rarely documented publicly or systematically evaluated, there is little evidence to guide the development of animal welfare education. A three-stage online Delphi study was used to identify who current interventions target, what delivery methods are being used, and how expert practitioners describe priorities and challenges in the field. Thirty-one experts participated in Round 1, with 84% of the sample (n = 26) also taking part in Round2. Qualitative analysis revealed passionate accounts about the far-reaching potential of educating children about animals. However, we also identified ambiguities and tensions that could thwart the future development of effective animal welfare education. Alongside the production of a web-based framework and evidence-based toolkit to support practitioners, findings will be used to encourage animal welfare professionals to work towards producing shared terminology, definitions, and outcomes frameworks; focusing on positive education and the idea of harm as opposed to cruelty. This should facilitate collaboration with schoolteachers and education policy-makers to assess the ways in which animal welfare might be successfully incorporated within formal education in the future. These data suggest many potential avenues for inclusion, although a holistic approach emphasising the links between humans, animals and the environment, within the context of young peoples recent activism and contemporary health, societal and environmental issues, may be most successful.

Tumor Necrosis Factor-alpha Blockade Improves Uterine Artery Resistance, Maternal Blood Pressure, and Fetal Growth in Placental Ischemic Rats

We recently reported that adoptive transfer of cytolytic Natural Killer cells (cNKs) from the Reduced Uterine Perfusion Pressure (RUPP) rat induces a preeclampsia (PE)-like phenotype in pregnant rats, accompanied by increased TNF-α. The purpose of this study was to investigate a role for increased TNF-α to induce oxidative stress (ROS), decrease nitric oxide (NO) bioavailability, and induce vascular dysfunction as mechanisms of hypertension (HTN) and intrauterine growth restriction (IUGR) in RUPPs. Pregnant Sprague Dawley rats underwent the RUPP or a Sham procedure on gestation day (GD) 14. On GDs 15 and 18, a subset of Sham and RUPP rats received i.p.injections of vehicle or 0.4 mg/kg of Etanercept (ETA), a soluble TNF-α receptor (n = 10/group). On GD18, Uterine Artery Resistance Index (UARI) was measured, and on GD19, mean arterial pressure (MAP), fetal and placental weights were measured, and blood and tissues were processed for analysis. TNF-α blockade normalized the elevated MAP observed RUPP. Additionally, both fetal and placental weights were decreased in RUPP compared to Sham, and were normalized in RUPP + ETA. Placental ROS was also increased in RUPP rats compared to Sham, and remained elevated in RUPP + ETA. Compared to Sham, UARI was elevated in RUPPs while plasma total nitrate was reduced, and these were normalized in ETA treated RUPPs. In conclusion, TNF-α blockade in RUPPs reduced MAP and UARI, improved fetal growth, and increased NO bioavailability. These data suggest that TNF-α regulation of NO bioavailability is a potential mechanism that contributes to PE pathophysiology and may represent a therapeutic target to improve maternal outcomes and fetal growth.

Angiotensin II type 1 receptor autoantibody blockade improves cerebral blood flow autoregulation and hypertension in a preclinical model of preeclampsia

Introduction:Women with preeclampsia (PE) and reduced uterine perfusion pressure (RUPP) pre-clinical rat model of PE have elevated angiotensin II type 1 receptor agonistic autoantibodies (AT1-AA) and cerebrovascular dysfunction. Methods:Sprague Dawley rats had RUPP surgery with/without AT1-AA inhibitor ('n7AAc'144 μg/day) osmotic minipumps. Mean arterial pressure (MAP), CBF autoregulation, blood brain barrier (BBB) permeability, cerebral edema, oxidative stress, and eNOS were assessed. Results:'n7AAc' improved MAP, restored CBF autoregulation, prevented cerebral edema, elevated oxidative stress, and increased phosphorylated eNOS protein in RUPP rats. Conclusion:Inhibiting the AT1-AA in placental ischemic rats prevents hypertension, cerebrovascular dysfunction, and improves cerebral metabolic function.

Treatment With Gemfibrozil Prevents the Progression of Chronic Kidney Disease in Obese Dahl Salt-Sensitive Rats

Recently, we reported that Dahl salt-sensitive leptin receptor mutant (SS^LepRmutant) rats exhibit dyslipidemia and renal lipid accumulation independent of hyperglycemia that progresses to chronic kidney disease (CKD). Therefore, in the current study, we examined the effects of gemfibrozil, a lipid-lowering drug (200 mg/kg/day, orally), on the progression of renal injury in SS and SS^LepRmutant rats for 4 weeks starting at 12 weeks of age. Plasma triglyceride levels were markedly elevated in the SS^LepRmutant strain compared to SS rats (1193 ± 243 and 98 ± 16 mg/day, respectively). Gemfibrozil treatment only reduced plasma triglycerides in the SS^LepRmutant strain (410 ± 79 mg/dL). MAP was significantly higher in the SS^LepRmutant strain vs. SS rats at the end of the study (198 ± 7 vs. 165 ± 7 mmHg, respectively). Administration of gemfibrozil only lowered MAP in SS^LepRmutant rats (163 ± 8 mmHg). During the course of the study, proteinuria increased to 125 ± 22 mg/day in SS rats. However, proteinuria did not change in the SS^LepRmutant strain and remained near baseline (693 ± 58 mg/day). Interestingly, treatment with gemfibrozil increased the progression of proteinuria by 77% in the SS^LepRmutant strain without affecting proteinuria in SS rats. The renal injury in the SS^LepRmutant strain progressed to CKD. Moreover, the kidneys from SS^LepRmutant rats displayed significant glomerular injury with mesangial expansion and increased renal lipid accumulation and fibrosis compared to SS rats. Treatment with gemfibrozil significantly reduced glomerular injury and lipid accumulation and improved renal function. These data indicate that reducing plasma triglyceride levels with gemfibrozil inhibits hypertension and CKD associated with obesity in SS^LepRmutant rats.

Abstract MP15: Treatment With IL-25 Slows The Early Progression Of Proteinuria In Obese Dahl Salt-sensitive Rats

Recently, we reported that the early progression of proteinuria in the obese Dahl salt-sensitive (SS LepR mutant) strain was associated with increased renal macrophage infiltration in the absence of hyperglycemia and elevations in arterial pressure. Macrophages (MØ) can be divided into two distinct phenotypes: M1-macrophages (classical; pro-inflammatory), and M2-macrophages (alternative; anti-inflammatory). M1-macrophages induce renal inflammation and fibrosis whereas M2-macrophages reduce renal inflammation and fibrosis. Moreover, previous studies have demonstrated that interlukin-25 (IL-25) converts resting MØ and M1 macrophages into M2 macrophages. Therefore, the objective of the current study was to examine whether treatment with IL-25 would reduce the early progression of proteinuria in SS LepR mutant rats by increasing renal M2 macrophages. Four week-old SS LepR mutant rats were separated into two groups (n=5/group): (1) vehicle (PBS) and (2) IL-25 (1μg/day, i.p.) for the first 10 days of the study. At baseline, proteinuria was similar in vehicle and IL-25 treated rats (81±18 vs. 66±8 mg/day, respectively). After 2 weeks, proteinuria was markedly reduced in the IL-25-treated group compared to the values measured in the vehicle treated rats (191±37 vs. 365±55 mg/day respectively; p<0.05 vs. vehicle). Interestingly, treatment with IL-25 was no longer effective in inhibiting the progression of proteinuria after 4 weeks (508±83 and 521±73 mg/day). When examining the possible phenotypes of the infiltrated macrophages in the kidneys, we did not detect any differences in M1 versus M2 macrophages between vehicle and IL-25 treated groups after 4 weeks. However, after 2 weeks of treatment, we did observe a tendency for M2 macrophages to be elevated in the kidneys of the IL-25 group. Overall, these data support our previous finding that the early progression of proteinuria in the obese SS LepR mutant strain is associated with renal macrophage infiltration and also suggest that IL-25 may be considered a therapeutic target for renal disease associated with obesity. This study was supported by DK109133. Key Words: Obesity, Renal Disease, Macrophages, IL-25

Abstract P213: Placental Ischemia-Stimulated Natural Killer Cells Contribute To Hypertension, Vascular Dysfunction, And Intrauterine Growth Restriction In Pregnant Rats

The Reduced Uterine Perfusion Pressure (RUPP) rat model of placental ischemia mimics many characteristics of preeclampsia (PE) such as hypertension (HTN), intrauterine growth restriction (IUGR), and increased cytolytic natural killer cells (cNKs). We have previously shown that natural killer (NK) cell depletion in RUPP rats improves PE pathophysiology and that RUPP NKs have a 5-fold increase in cytotoxicity vs normal pregnant NKs. In this study, we tested the hypotheses that (1) RUPP stimulated NKs play a direct role in causing HTN and IUGR in pregnant rats and (2) normal pregnant control (Sham) NKs attenuate HTN and IUGR in RUPP rats. NKs were isolated from the placentas of Sham and RUPP rats on gestation day (GD) 19. On GD14, vehicle or 5x10 6 RUPP NKs were infused i.v. into a subset of Sham rats, and vehicle or 5x10 6 Sham NKs were infused i.v. into a subset of RUPP rats. On GD18, Uterine Artery Resistance Index (UARI) was measured via Doppler Ultrasound; GD19, cNKs were quantified via flow cytometry and MAP, fetal weight, and blood were acquired. Plasma VEGF and sFlt-1 were measured via ELISA. Placental cNKs (% gated) increased from 3±1% in Sham to 19±5% in RUPP and 21±4% in Sham+RUPP NK (p<0.05 vs Sham), and decreased to 3±1% in RUPP+Sham NK (p<0.05 vs RUPP). Circulating cNKs also followed this trend. MAP increased from 102±1 mmHg in Sham to 130±2 mmHg in RUPP and 121±2 mmHg in Sham+RUPP NK (p<0.05 vs Sham), and was blunted to 113±1 mmHg in RUPP+Sham NK (p<0.05 vs RUPP). Fetal weight decreased from 2.4±0.04 g in Sham to 2.1±0.07 g in RUPP and 2.1±0.03 g in Sham+RUPP NK (p<0.05 vs Sham), and this was normalized to 2.3±0.03 g in RUPP+Sham NK (p<0.05 vs RUPP). UARI increased from 0.56±0.05 in Sham to 0.75±0.06 in RUPP and 0.76±0.05 in Sham+RUPP NK (p<0.05 vs Sham), and decreased to 0.64±0.05 in RUPP+Sham NK (p<0.05 vs RUPP). Circulating sFlt-1 increased from 76±15 pg/mL in Sham to 1391±424 pg/mL in RUPP (p<0.05 vs Sham), 780±256 pg/mL in Sham+RUPP NK, and decreased to 67±8 pg/mL in RUPP+Sham NK (p<0.05 vs RUPP). Furthermore, circulating VEGF decreased in RUPP and Sham+RUPP NK compared to Sham (p<0.05), and increased in RUPP+Sham NK (p<0.05 vs RUPP). These data demonstrate a direct role for cNKs to mediate vascular dysfunction in PE and for normal NKs to promote positive maternal and fetal outcomes.

NLRP3 inflammasome inhibition attenuates sepsis-induced platelet activation and prevents multi-organ injury in cecal-ligation puncture

Sepsis is characterized by organ dysfunction due to a dysregulated immune response to infection. Currently, no effective treatment for sepsis exists. Platelets are recognized as mediators of the immune response and may be a potential therapeutic target for the treatment of sepsis. We previously demonstrated that NLRP3 inflammasome activation in sepsis-induced activated platelets was associated with multi-organ injury in the cecal-ligation puncture (CLP) rat model of sepsis. In this study, we tested the hypothesis that inhibition of NLRP3 would inhibit platelet activation and attenuate multi-organ injury in the CLP rat. CLP (n = 10) or Sham (n = 10) surgery were performed in male and female Sprague-Dawley rats. A subset of CLP rats were treated with MCC950 (50mg/kg/d), a specific NLRP3 inhibitor (CLP+MCC950, n = 10). At 72 hrs. post-CLP, blood and organs were harvested for analysis of platelet activation, NLRP3 activation, inflammation and end organ damage. Platelet activation increased from 8±0.8% in Sham to 16±1% in CLP, and was reduced to 9±1% in CLP+M rats (p<0.05). NLRP3 activation was also increased in platelets of CLP vs Sham. NLRP3 expression was unchanged in kidney and lung after CLP, but Caspase 1 expression and IL-1β were increased. MCC950 treatment attenuated NLRP3 activation in platelets. Plasma, kidney, and lung levels of NLRP3 inflammasome associated cytokines, IL-1ß and IL-18, were significantly increased in CLP compared to Sham rats. Inhibition of NLRP3 normalized cytokine levels. Glomerular injury, pulmonary edema, and endothelial dysfunction markers were increased in CLP rats vs Sham. MCC950 treatment significantly decreased renal and pulmonary injury and endothelial dysfunction in CLP+M. Our results demonstrate a role for NLRP3 in contributing to platelet activation and multi-organ injury in sepsis.

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.