The aim of this study was to observe the change in angiotensin II receptor subtype 1 (AT(1)) autoantibody during the development of renovascular hypertension (RVH). The Goldblatt renovascular hypertension model was established by the two-kidney one-clip method, and a synthetic peptide corresponding to amino acid sequence 165-191 of the second extracellular loop of the AT(1)-receptor was used as the antigen. Sera AT(1)-receptor autoantibody was detected by SA-ELISA. It was shown that two weeks after operation both the frequency of occurrence and the titre of autoantibodies to AT(1)-receptor were significantly increased as compared with the pre-treatment control. The increase in autoantibodies lasted several weeks and then decreased gradually to the pre-clipping level at 12 weeks. It is suggested that autoimmune mechanisms are involved in the pathogenesis of renovascular hypertension and the AT(1) autoantibodies may be one of the mechanisms leading to cardiac hypertrophy.
Animals ; Autoantibodies ; blood ; Disease Models, Animal ; Hypertension, Renovascular ; blood ; immunology ; Kidney ; physiopathology ; Rats ; Receptor, Angiotensin, Type 1 ; immunology ; metabolism

OBJECTIVETo determine whether autoantibodies against the cardiac G-protein-coupled beta 2- and alpha 1-adrenergic and AT1 receptors are related to patients with primary hypertension.

METHODSSynthetic peptides corresponding to amino acid sequences of the second extracellular loops of the beta 2- and alpha 1-adrenergic and AT1 receptors were respectively used as antigens to screen sera from patients with hypertensive heart diseases (n = 50) as well as simple hypertension (n = 40) and healthy blood donors (n = 40) using ELISA test.

RESULTSThe positive ratio of autoantibodies against beta 2 and alpha 1 and AT1 receptors in patients with hypertensive heart diseases were significantly higher than patients with simple hypertension and healthy donors. The geometric mean titers of autoantibodies against beta 2- and alpha 1-adrenergic and AT1 receptors had no difference between the patients with hypertensive heart diseases and the patients with simple hypertension, but the geometric mean titers of two groups were higher than healthy donors. In the patients with hypertensive heart diseases, 81.0% of the patients with autoantibodies against beta 2-adrenergic receptor had autoantibodies against alpha 1-adrenergic receptor and 76.2% had autoantibodies against AT1 receptors. The percent of the autoantibodies against three receptors in patients with hypertensive heart diseases were 52.4%.

CONCLUSIONSAutoantibodies against beta 2- and alpha 1-adrenergic and AT1 receptors play an important role in the pathophysiological changes of primary hypertension, and may participate myocardial and vessel remodeling.

Adult ; Aged ; Autoantibodies ; blood ; Female ; Humans ; Hypertension ; immunology ; Male ; Middle Aged ; Receptor, Angiotensin, Type 1 ; immunology ; Receptors, Adrenergic, alpha-1 ; immunology ; Receptors, Adrenergic, beta-2 ; immunology

OBJECTIVETo observe autoantibodies production against AT(1)-receptors and alpha(1)-adrenergic receptors and association to risk factors, such as sex, age, family history, course of hypertension and other cardiovascular diseases in hypertensive patients.

METHODSA total of 690 patients with essential hypertension admitted to our hospital were selected and autoantibodies against AT(1)-receptors and alpha(1)-adrenergic receptors were detected by ELISA. Multiple logistic regression analysis was performed based on obtained data.

RESULTSPositive rates for antibody against AT(1)-receptors and alpha(1)-adrenergic receptors were 47.1% (325/690) and 36.4% (251/690) respectively in this group of patients. Duration of hypertension history was significantly longer in the antibody against AT(1)-receptors and alpha(1)-adrenergic receptors positive groups [(9.3 +/- 11.0) year, (9.9 +/- 11.1) year] compared to the negative groups [(7.3 +/- 9.3) year, (7.2 +/- 9.5) year, all P < 0.01]. The ratio of family history with hypertension was also significantly higher in antibody positive groups than negative ones (47.69% vs 39.18%, P < 0.01). Regression analysis demonstrated that 5 risk factors were related to positive production of autoantibody against AT(1)-receptors including female gender, age, family history, duration of hypertension history and diabetes. However, just age, family history, duration of hypertension history were main factors responsible to the production of autoantibody against alpha(1)-adrenergic receptors (all P < 0.05).

CONCLUSIONThe environmental and genetic factors contributed to the autoantibody production in patients with essential hypertension.

Adult ; Autoantibodies ; blood ; Female ; Humans ; Hypertension ; blood ; immunology ; Male ; Middle Aged ; Receptor, Angiotensin, Type 1 ; immunology ; Receptors, Adrenergic, alpha ; immunology ; Risk Factors

OBJECTIVETo observe the positive rates of autoantibodies against beta1 adrenergic receptors (beta1-receptor) and angiotensin II type 1 receptors (AT(1)-receptor) in type 2 diabetes patients with or without hypertension.

METHODSThe epitopes of the second extracellular loop of beta1-receptor (197 - 222) and AT(1) receptor (165 - 191) were synthesized and serum autoantibodies were determined in type 2 diabetes patients with hypertension (n = 171) or without hypertension (n = 106). Left ventricular dimension was determined by echocardiography. The 24-hour urinary protein was measured by ELISA. The risk factors for enlarged left ventricle were analyzed by multiple logistic regressions.

RESULTSThe positive rates of the autoantibodies against beta1-receptors (45.0%) and AT(1)-receptor (46.2%) in patients with type 2 diabetes with hypertension were significantly higher than those in patients with type 2 diabetes without hypertension (16.0% and 10.4%, respectively, all P < 0.01). In type 2 diabetes patients with hypertension and enlarged left ventricle, the positive rates of the autoantibodies against beta1-receptor 61.4% (35/57) and against AT(1)-receptor 64.9% (37/57)were significantly higher than those in type 2 diabetes patients with normal left ventricular dimension (36.8%, 42/114 and 36.8%, 42/114, respectively, all P < 0.01). Regression analysis demonstrated that course of disease, systolic pressure, serum autoantibodies against beta1 adrenergic receptor and angiotensin II type 1 receptors sera autoantibodies were independent risk factors for left ventricular enlargement (all P < 0.05).

CONCLUSIONThe serum beta1 and AT(1)-receptor autoantibodies are related to enlarged left ventricle in type 2 diabetes patients with hypertension and suggest that autoantibodies against beta1 and AT(1)-receptor might play important roles in the pathogenesis of type 2 diabetes patients with hypertension and enlarged left ventricle.

Aged ; Autoantibodies ; blood ; Diabetes Mellitus, Type 2 ; complications ; immunology ; Female ; Humans ; Hypertrophy, Left Ventricular ; complications ; immunology ; Male ; Middle Aged ; Receptor, Angiotensin, Type 1 ; immunology ; Receptors, Adrenergic, beta-1 ; immunology

OBJECTIVETo observe the association between positive autoantibodies against AT(1)-receptor and cardiac remodeling in primary hypertensive patients.

METHODSEchocardiography was performed and serum autoantibodies against AT(1)-receptor were detected by enzyme linked immunosorbent assay (ELISA) in 592 patients with primary hypertension. The differences on blood pressure level, course of hypertension, vasoactive substance and echocardiography parameters between the positive group and negative group were compared. Factors related to left ventricular enlargement were analyzed by multiple logistic regressions.

RESULTSThe positive percentage of autoantibodies against AT(1)-receptor was 38.0% (225/592). End-diastolic right atrial and left ventricular diameters in positive group were significantly larger than that in negative group (P = 0.049 and P = 0.044, respectively). Regression analysis demonstrated that positive autoantibodies against AT(1)-receptor, male gender, diastolic blood pressure and course of hypertension were related to left ventricular enlargement (all P < 0.05).

CONCLUSIONThe autoantibodies against AT(1)-receptor is associated with left ventricular and right atrial enlargement in hypertensive patients.

Adult ; Aged ; Autoantibodies ; blood ; Female ; Heart Ventricles ; physiopathology ; Humans ; Hypertension ; blood ; immunology ; physiopathology ; Hypertrophy, Left Ventricular ; Male ; Middle Aged ; Receptor, Angiotensin, Type 1 ; immunology ; Ventricular Remodeling

BACKGROUNDStudies have confirmed that angiotensin II receptor blocker (ARB) and angiotensin converting enzyme inhibitors (ACEI) in the treatment of diabetic nephropathy (DN) has special advantages. We observed the effects of valsartan and metoprolol tartrate hydrchloride in treatment of DN patients with positive β1-adrenergic and anti-angiotensin II type 1 (AT1) receptor antibody.

METHODSThe epitopes of the second extracellular loop of β1 receptor (197 - 222) and AT1 receptor (165 - 191), were synthesized and used respectively to screen serum autoantibodies from patients with DN (n = 371, group A), diabetes mellitus (DM) without renal failure (n = 107, group B) and healthy blood donors (n = 47, control, group C) by enzyme-linked immunosorbent assay (ELISA). Metoprolol tartrate 25 - 50 mg, three times per day, valsartan 160 mg, once a day, aspirin 100 mg, once a day, and nitrendipine 10 - 20 mg, three times per day, were given to DN patients with positive or negative autoantibodies. The cystatin C level and 24-hour urinary protein were measured before and after treatment.

RESULTSIn DN patients, the positive rate of the autoantibodies against β1 receptors and AT1 receptor was 47.7% and 51.5%, respectively, which were significantly higher than those in DM patients and healthy controls (all P < 0.01). Patients with anormalous cystatin C had higher positive rates of the autoantibodies than patients with normal cystatin C. Valsartan and metoprolol tartrate reduced proteinuria significantly (P < 0.01) in DN patients with positive autoantibodies.

CONCLUSIONSThe findings suggest that these autoantibodies against β1 and AT1-receptor may play important roles in the pathogenesis of DN. Valsartan and metoprolol tartrate are effective and safe in the treatment of DN.

Aged ; Autoantibodies ; immunology ; Diabetic Nephropathies ; drug therapy ; immunology ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Male ; Metoprolol ; therapeutic use ; Receptor, Angiotensin, Type 1 ; immunology ; Receptors, Adrenergic, beta-1 ; immunology ; Tetrazoles ; therapeutic use ; Valine ; analogs & derivatives ; therapeutic use ; Valsartan

BACKGROUNDAutoantibodies against angiotensin AT1 receptor have been discovered in patients with preeclampsia or malignant hypertension. Some studies have demonstrated that the autoantibodies are involved in the immunopathogenesis of hypertension and have an agonist effect similar to angiotensin II.

METHODSAutoantibodies against AT1 receptor were purified from sera of patients with primary hypertension by affinity chromatography. Proliferation of cultured rat vascular smooth muscle cells was detected by bromodeoxyuridine incorporation and activation of signalling molecules detected by Western blotting and electrophoretic mobility shift assay.

RESULTSThe AT1-RAb caused a significant proliferation similar to the Ang II during first 24 hours. The levels of nuclear factor-kappaB (NF-kappaB), phosphorylated JAK2, phosphorylated STAT1 (pSTAT1) and phosphorylated STAT3 (pSTAT3) molecules were increased in response to the autoantibodies. In contrast, the activations of NF-kappaB and JAK-STAT were blocked by losartan, pyrrolidinedithiocarbamate (a specific inhibitor of NF-kappaB) and AG490 (a specific inhibitor of the JAK2 tyrosine kinase). The expressions of NF-kappaB, pSTAT1 and pSTAT3 reached peak levels at different times. Moreover, the relative densities of electrophoretic bands showed that activation of pSTAT3 was more significant than STAT1 induced by AT1-RAb.

CONCLUSIONSThese results suggest that the autoantibodies against AT1 receptor have an agonist effect similar to Ang II in proliferation of VSMCs and the NF-kappaB and JAK-STAT proteins play essential roles. The effect is different from Ang II in that STAT3 is the main downstream activating molecule in JAK-STAT signalling pathway.

Animals ; Autoantibodies ; immunology ; Cell Proliferation ; Humans ; Hypertension ; immunology ; Janus Kinase 2 ; physiology ; Muscle, Smooth, Vascular ; cytology ; NF-kappa B ; physiology ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; immunology ; STAT3 Transcription Factor ; physiology ; Signal Transduction ; physiology

Using two-kidney one-clip renal hypertensive (2K1C group), stress-induced hypertensive (neural group), DOCA-salt treated hypertensive (DOCA group) and spontaneously hypertensive rats (SHR group), to investigate the change in AT(1A)-receptor autoantibodies (AT(1A)-AAs) during the development of the four types of hypertension. The biological activities of AT(1A)-AAs were examined. It was shown that the frequency of occurrence and titres of AT(1A)-AAs increased significantly during the development of hypertension. In the four hypertensive groups studied, the occurrence of AT(1A)-AAs was most prominent in SHR, 2K1C and neural groups. The biological effects of AT(1A)-AAs were shown to increase the beating frequency of cultured neonatal myocardial and vascular contractile tension. It is suggested that autoimmune mechanisms are involved the pathogenesis of different types of hypertension and the AT(1A)-AAs may be one of the mechanisms leading to cardiac hypertrophy.
Animals ; Autoantibodies ; blood ; Desoxycorticosterone ; administration & dosage ; Hypertension ; classification ; etiology ; immunology ; physiopathology ; Hypertension, Renovascular ; immunology ; physiopathology ; Male ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; immunology ; Stress, Physiological ; physiology

BACKGROUND: Angiotensin II type 1 receptor (AT1R) is responsible for cardiovascular effects mediated by angiotensin II. This study aimed to investigate the impact of antibodies directed against AT1R (anti-AT1R) in renal allograft rejection. METHODS: We evaluated 53 patients who had biopsy-proven rejection including antibody-mediated rejection (AMR) (N=22), T-cell-mediated rejection (TCMR) (N=29), and mixed AMR and TCMR (N=2). Donor specific HLA antibodies (DSA) and anti-AT1Rs were simultaneously determined. RESULTS: Anti-AT1Rs were detected in 9.4% (5/53) of rejection patients (one with acute AMR, two with chronic active AMR, one with acute TCMR, and one with mixed acute AMR & TCMR). HLA antibodies and DSA were detected in 75.5% (40/53) and 49.1% (26/53) of patients, respectively. There was no significant difference in transplant characteristics between anti-AT1R(+) and anti-AT1R(-) patients except for the association of HLA class-I DSA(+) and anti-AT1R(+). Four of five anti-AT1R(+) patients had DSA and were also found to have AMR. A single anti-AT1R(+)/DSA(-) patient developed acute TCMR. Detection rates of DSA, HLA antibodies, or anti-AT1R were not different between AMR and TCMR. However, DSA(+)/anti-AT1R(+) was more frequently found in AMR than in TCMR (P=0.036). Patients with anti-AT1R showed a greater tendency to develop high-grade rejection as Banff IIA/IIB or AMR. CONCLUSIONS: The presence of anti-AT1R was significantly associated with HLA class-I DSA in renal allograft rejection patients. Both anti-AT1R and DSA positivity was associated with AMR in patients with renal allograft rejection.
Adult ; Antibodies/blood ; Female ; Graft Rejection/*etiology ; HLA Antigens/immunology ; Humans ; Kidney/pathology ; Kidney Transplantation/*adverse effects ; Male ; Middle Aged ; Receptor, Angiotensin, Type 1/*immunology ; Tissue Donors ; Transplantation, Homologous

Antibody against the angiotensin AT1 receptor (AT1-Ab) could disturb placental development. The placenta is the key organ between mother and fetus. Placental damage will seriously impair fetal growth and development in utero, leading to intrauterine growth restriction (IUGR). Based on the fetal origins of adult disease (FOAD) hypothesis, IUGR could increase a propensity to develop adult onset cardiovascular disease (CVD). The present study was designed to determine whether vascular function has changed in the adult offspring of AT1-Ab positive pregnant rats. Twenty four female rats (8-week-old, AT1-Ab negative) were randomly divided into two groups, immunized and vehicle groups. Immunized group received active immunization to establish AT1-Ab-positive model, while vehicle group was subjected to Freund's adjuvant without antigen. After 8 weeks of immunization, the antibody titers in sera from the female rats were detected by enzyme-linked immunosorbent assay (ELISA). Then all the female rats were mated with normal Wistar male rats and became pregnant. Immunized/vehicle group offspring rats (I offspring/V offspring) were raised to 40-week-old under standard chow feeding. Then the two groups' offspring rats were given a high-salt diet for 12 weeks (4% NaCl in chow feeding). Systolic blood pressure (SBP) was measured dynamically by noninvasive blood pressure system. The vascular ring experiment was performed to detect vascular function and reactivity. As detected by ELISA, the titers of antibody peaked at the 8th week (OD values: 2.75 ± 0.08 vs 0.33 ± 0.01, P < 0.01 vs vehicle group at the same time point). There was no significant difference of SBP between the two groups' offspring rats during the high-salt diet (P > 0.05). Isolated thoracic aortic rings of I offspring had significantly decreased constriction under norepinephrine treatment (P < 0.01 vs V offspring) and significantly decreased dilation under acetylcholine treatment (P < 0.05 vs V offspring). These results suggest that the offspring of AT1-Ab-positive pregnant rats are more susceptible to vascular functional abnormality while being fed high-salt diet.
Animals ; Antibodies ; blood ; Cardiovascular Diseases ; etiology ; physiopathology ; Disease Susceptibility ; Female ; Fetal Growth Retardation ; physiopathology ; Immunization ; Pregnancy ; Prenatal Exposure Delayed Effects ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; immunology ; Sodium Chloride, Dietary ; administration & dosage ; adverse effects