Abstract-Agonistic autoantibodies to the angiotensin II type I receptor (AT1-AA) and endothelin -1 (ET-1) are suggested to be important links between placental ischemia and hypertension during preeclampsia. Activation of the angiotensin II type 1 receptor (AT1R) increases endothelial cell production of ET-1; however, the importance of ET-1 in response to AT1-AA-mediated AT1 R activation during preeclampsia is unknown. Furthermore, the role of AT1-AA-mediated increases in blood pressure during pregnancy remains unclear. The objective of this study was to test the hypothesis that AT1-AA, increased to levels observed in preeclamptic women and placental ischemic rats, increases mean arterial pressure (MAP) by activation of the ET-1 system. Chronic infusion of purified rat AT1-AA into normal pregnant (NP) rats for 7 days increased AT1-AA from 0.68Ϯ0.5 to 10.88Ϯ1.1 chronotropic units (PϽ0.001). The increased AT1-AA increased MAP from 99Ϯ1 to 119Ϯ2 mm Hg (PϽ0.001). The hypertension was associated with significant increases in renal cortices (11-fold) and placental (4-fold) ET-1. To determine whether ET-1 mediates AT1-AA-induced hypertension, pregnant rats infused with AT1-AA and NP rats were treated with an ET A receptor antagonist. MAP was 100Ϯ1 mm Hg in AT1-AAϩET A antagonist-treated rats versus 98Ϯ2 mm Hg in ET A antagonist-treated rats. Collectively, these data support the hypothesis that one potential pathway whereby AT1-AAs increase blood pressure during pregnancy is by an ET-1-dependent mechanism. Key Words: preeclampsia Ⅲ hypertension Ⅲ kidney Ⅲ placenta Ⅲ inflammation T he initiating event in early onset preeclampsia is postulated to involve inadequate vascularization of the subplacental decidua with reduced placental perfusion that leads to hypertension during pregnancy by mechanisms not yet elucidated. 1,2 Recent studies have suggested that the production of agonistic autoantibodies to the angiotensin II (Ang II) type I receptor (AT1-AA) may be an important link between placental ischemia and hypertension in preeclamptic women. 3-8 The AT1-AA induces signaling in vascular cells that are blocked by an AT1 receptor antagonist including activating protein-1, calcineurin, and nuclear factor kappa B activation. 3,4,7 Recent studies by Zhou et al demonstrate that immunoglobulin isolated from preeclamptic women increases systolic blood pressure 4 days after retro-orbital injection into pregnant mice. 7,8 This hypertensive response was attenuated by administration of an AT1 receptor antagonist. Although these findings suggest that AT1-AAs from preeclamptic women increases blood pressure in pregnant mice, possibly by activation of the AT1 receptor, it remains unclear by what mechanism purified AT1-AA mediates hypertension during pregnancy.We recently reported that hypertension in response to reductions in uterine perfusion pressure in pregnant rats (RUPP) is associated with increased circulating levels of the AT1-AA. 9,10 Moreover, we found that the increased blood pressure response in RUPP pregnant rats decreased ma...

Abstract-Chronic inflammation has been implicated in the pathology of hypertension; however, the role for specific cytokines remains unclear. We tested whether tumor necrosis factor-␣ blockade with etanercept (Etan) reduces mean arterial pressure in a female mouse model of systemic lupus erythematosus (SLE). SLE is a chronic inflammatory disorder with prevalent hypertension. and lowered in Etan-treated SLE mice (6645Ϯ490). Renal cortex nuclear factor B (phosphorylated and nonphosphorylated) was increased in SLE mice compared with controls and lower in Etan-treated SLE mice. These data suggest that TNF-␣ mechanistically contributes to the development of hypertension in a chronic inflammatory disease through increased renal nuclear factor B, oxidative stress, and inflammation. (Hypertension. 2010;56:643-649.) Key Words: systemic lupus erythematosus Ⅲ hypertension Ⅲ inflammation Ⅲ TNF-␣ Ⅲ oxidative stress Ⅲ cytokine A growing body of literature suggests that chronic inflammation plays an important role in the progression of several forms of hypertension. Plasma levels of inflammatory cytokines, such as tumor necrosis factor-␣ (TNF-␣) and interleukin 6, directly correlate with blood pressure and essential hypertension in humans. 1,2 In addition, recent studies demonstrate that immunosuppressive therapy with mycophenolate mofetil reduced blood pressure in essential hypertensive patients 3 and in experimental animal models of hypertension. 4 The potential mechanistic role of specific inflammatory cytokines, such as TNF-␣, in the development of hypertension remains unclear. For example, the effect of TNF-␣ blockade in experimental models of hypertension varies, ranging from having no effect on pressure 5,6 to delaying the progression 7 or even completely ameliorating hypertension. 8 Therefore, further studies to understand the contribution of this master immune regulator to the development of hypertension are warranted.Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder of unknown etiology that predominantly affects young women. A loss of immunologic tolerance during SLE leads to the production of autoantibodies, of which antidouble-stranded DNA (dsDNA) is the most common and is specific for the disease. Autoantibody production facilitates the formation of immune complexes that deposit in tissues and promote local inflammation and injury, with the kidneys being most commonly affected. Numerous inflammatory cytokines are implicated in the pathophysiology of SLE, including TNF-␣. 9,10 TNF-␣ expression is increased in kidney biopsies, 11 and the prevalence of hypertension is elevated in patients with SLE, reaching as high as 75%, depending on the cohort. [12][13][14][15] These data suggest that SLE may be an important disease model to examine the mechanistic role of renal TNF-␣ in the development of hypertension.In the present study, we hypothesize that TNF-␣ is an important mediator of hypertension during the chronic in-

-Women with systemic lupus erythematosus (SLE) exhibit a high prevalence of hypertension and renal injury. Rosiglitazone (Rosi), a peroxisome proliferator activator receptor gamma (PPAR␥) agonist, has renal protective and antihypertensive effects. We tested whether Rosi ameliorates hypertension and renal injury in a female mouse model of SLE (NZBWF1). Thirty-week-old SLE and control (NZW/LacJ) mice (n Ն 6/group) were fed Rosi (5 mg ⅐ kg Ϫ1 ⅐ day Ϫ1 in standard chow) or standard chow for 4 wk. SLE mice had increased blood pressure (BP in mmHg) compared with controls (139 Ϯ 4 vs. 111 Ϯ 4, P Ͻ 0.05). Rosi treatment lowered BP in SLE mice (127 Ϯ 4, P Ͻ 0.05) but not in controls (111 Ϯ 4). Urinary albumin (g/mg creatinine) was increased in SLE mice compared with controls (12,396 Ϯ 6,525 vs. 50 Ϯ 6) and reduced with Rosi treatment (148 Ϯ 117). Glomerulosclerosis (% of glomeruli with sclerosis) was reduced in Rosi-treated SLE mice (4.2 Ϯ 1.6 vs. 0.4 Ϯ 0.3, P Ͻ 0.05). Renal monocyte/ macrophage numbers (cell number/1,320 points counted) were reduced in SLE mice treated with Rosi (32.6 Ϯ 11.0 vs. 10.6 Ϯ 3.6, P Ͻ 0.05) but unchanged in controls (3.7 Ϯ 1.6 vs. 3.7 Ϯ 2.0). Renal osteopontin expression, a cytokine-regulating macrophage recruitment, was reduced in Rosi-treated SLE mice. Urinary endothelin (in pg/mg creatinine) was increased in SLE mice compared with controls (1.9 Ϯ 0.59 vs. 0.6 Ϯ 0.04, P Ͻ 0.05) and reduced in SLE mice treated with Rosi (0.8 Ϯ 0.11, P Ͻ 0.05). PPAR␥ protein expression in the renal cortex was significantly lower in SLE mice compared with controls and was unaffected by Rosi. These data suggest that Rosi may be an important therapeutic option for the treatment of SLE hypertension and renal injury. lupus; inflammation; endothelin; glomerulosclerosis; proliferator activated receptor gamma SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) is a chronic autoimmune inflammatory disorder that has a strong predilection for women during their reproductive years. The hallmark of the disease is the production of autoantibodies such as antinuclear antibodies, and more specifically anti-double-stranded DNA (antidsDNA) antibodies. Accumulating evidence indicates that the major cause of death among patients with SLE is cardiovascular disease (17,22,23,26). Indeed, studies have reported that women with SLE are at a 50-fold greater risk for developing cardiovascular disease independent of traditional Framingham Heart Study risk factors (35). One of the major factors contributing to the progression of cardiovascular disease is increased arterial pressure. Importantly, SLE is associated with a high incidence of hypertension (1, 41, 56).The kidneys are prominently affected during SLE in the form of immune complex glomerulonephritis. This occurs in greater than 50% of patients with SLE (18) and is caused, in part, by circulating anti-dsDNA antibody-mediated formation of immune complexes (51). Few advances have been made toward the treatment of SLE and the associated nephritis and hypertension in the past 40 years. Patients with SL...

One potential mechanism contributing to the increased risk for encephalopathies in women with preeclampsia is altered cerebral vascular autoregulation resulting from impaired myogenic tone. Whether placental ischemia, a commonly proposed initiator of preeclampsia, alters cerebral vascular function is unknown. This study tested the hypothesis that placental ischemia in pregnant rats (induced by reducing uterine perfusion pressure, RUPP) leads to impaired myogenic responses in middle cerebral arteries (MCA). Mean arterial pressure (in mmHg) was increased by RUPP (135±3) compared with normal pregnant rats (NP, 103±2) and non-pregnant controls (Ctrl, 116±1). MCA from rats sacrificed on gestation day 19 were assessed in a pressure ateriograph under active (+ Ca2+) and passive (0 Ca2+) conditions while luminal pressure was varied between 25 and 150 mmHg. The slope of the relationship between tone and pressure in the MCA was 0.08±0.01 in CTRL rats and was similar in NP rats (0.05±0.01). In the RUPP model of placental ischemia, this relationship was markedly reduced (slope = 0.01±0.00, p<0.05). Endothelial dependent and independent dilation was not different between groups nor was there evidence of vascular remodeling assessed by the wall:lumen ratio and calculated wall stress. The impaired myogenic response associated with brain edema measured by % water content (RUPP p<0.05 vs. CTRL and NP). This study demonstrates that placental ischemia in pregnant rats leads to impaired myogenic tone in the MCA and that the RUPP model is a potentially important tool to examine mechanisms leading to encephalopathy during preeclamptic pregnancies.