Mechanism of herbal medicine on hypertensive nephropathy (Review).

Hypertensive nephropathy is the most common complication of hypertension, and is one of the main causes of end­stage renal disease (ESRD) in numerous countries. The basic pathological feature of hypertensive nephropathy is arteriolosclerosis followed by renal parenchymal damage. The etiology of this disease is complex, and its pathogenesis is mainly associated with renal hemodynamic changes and vascular remodeling. Despite the increased knowledge on the pathogenesis of hypertensive nephropathy, the current clinical treatment methods are still not effective in preventing the development of the disease to ESRD. Herbal medicine, which is used to relieve symptoms, can improve hypertensive nephropathy through multiple targets. Since there are few clinical studies on the treatment of hypertensive nephropathy with herbal medicine, this article aims to review the progress on the basic research on the treatment of hypertensive nephropathy with herbal medicine, including regulation of the renin angiotensin system, inhibition of sympathetic excitation, antioxidant stress and anti­inflammatory protection of endothelial cells, and improvement of obesity­associated factors. Herbal medicine with different components plays a synergistic and multi­target role in the treatment of hypertensive nephropathy. The description of the mechanism of herbal medicine in the treatment of hypertensive nephropathy will contribute towards the progress of modern medicine.

In renal hypertension, Cirsium japonicum strengthens cardiac function via the intermedin/nitric oxide pathway.

Cirsium japonicum, a constituent of traditional Chinese medicine, has been shown to exert inflammatory effects as well as to improve the circulation and thus to counteract hematologic stasis. Studies have demonstrated that intermedin (IMD) has protective effects on hypertension in rats by regulating the Ang/NO metabolic pathway. In this study, we investigated whether by regulating the expression of IMD, Cirsium japonicum could improve cardiac function in rats with 2k1c-induced renal hypertension. Renal hypertension was induced in Sprague-Dawley rats by occluding the renal artery. The rats were maintained on a normal diet and randomly divided into four groups: sham, 2k1c, 2k1c with Cirsium japonicum (1.8 g/kg per day) and 2k1c with IMD (n = 10 in each group). Cardiac function, plasma angiotensin II (Ang II), IMD, serum nitric oxide (NO) and nitric oxide synthase (NOS), as well as the expression of IMD and adrenomedullin (ADM) in the aorta and left ventricle were analyzed. Administration of Cirsium japonicum or IMD significantly strengthened cardiac function in 2k1c-induced rats, increased serum NO and NOS levels, reduced plasma Ang II, and upregulated IMD expression in the aorta and left ventricle. These results demonstrate that Cirsium japonicum has cardioprotective effects on 2k1c-induced renal hypertension in rats via the IMD/NO pathway.

Activation of TRPV4 by dietary apigenin antagonizes renal fibrosis in deoxycorticosterone acetate (DOCA)-salt-induced hypertension.

Hypertension-induced renal fibrosis contributes to the progression of chronic kidney disease, and apigenin, an anti-hypertensive flavone that is abundant in celery, acts as an agonist of transient receptor potential vanilloid 4 (TRPV4). However, whether apigenin reduces hypertension-induced renal fibrosis, as well as the underlying mechanism, remains elusive. In the present study, the deoxycorticosterone acetate (DOCA)-salt hypertension model was established in male Sprague-Dawley rats that were treated with apigenin or vehicle for 4 weeks. Apigenin significantly attenuated the DOCA-salt-induced structural and functional damage to the kidney, which was accompanied by reduced expression of transforming growth factor-ß1 (TGF-ß1)/Smad2/3 signaling pathway and extracellular matrix proteins. Immunochemistry, cell-attached patch clamp and fluorescent Ca2+ imaging results indicated that TRPV4 was expressed and activated by apigenin in both the kidney and renal cells. Importantly, knockout of TRPV4 in mice abolished the beneficial effects of apigenin that were observed in the DOCA-salt hypertensive rats. Additionally, apigenin directly inhibited activation of the TGF-ß1/Smad2/3 signaling pathway in different renal tissues through activation of TRPV4 regardless of the type of pro-fibrotic stimulus. Moreover, the TRPV4-mediated intracellular Ca2+ influx activated the AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) pathway, which inhibited the TGF-ß1/Smad2/3 signaling pathway. In summary, dietary apigenin has beneficial effects on hypertension-induced renal fibrosis through the TRPV4-mediated activation of AMPK/SIRT1 and inhibition of the TGF-ß1/Smad2/3 signaling pathway. This work suggests that dietary apigenin may represent a promising lifestyle modification for the prevention of hypertension-induced renal damage in populations that consume a high-sodium diet.

Traditional thermal therapy with indirect moxibustion decreases renal arterial resistive index.

OBJECTIVE: To evaluate the immediate effects of indirect moxibustion, a traditional local thermal therapy, on renal hemodynamics by using Doppler ultrasonography (US). DESIGN: Prospective observational study of postintervention changes in several variables. SETTING: Gifu University Hospital, Gifu, Japan. PARTICIPANTS: Eleven healthy persons (7 men and 4 women; mean age±standard deviation, 32.6±5.7 years) were enrolled. INTERVENTION: Indirect moxibustion was applied for 4 minutes to bilateral lower back acupuncture points (BL23). Each participant received 3 successive treatments. OUTCOME MEASURES: The main outcome measurement was resistive index (RI) in the renal segmental arteries. Blood flow variables, including RI, were measured for 6 renal segmental arteries by Doppler US at rest (baseline), immediately after completion of moxibustion (post 1), and 10 minutes later (post 2). Participants were monitored for adverse events during the intervention. RESULTS: The mean RI was 0.578±0.037 at baseline, 0.546±0.027 at post 1, and 0.547±0.032 at post 2. RI decreased significantly between post 1 and baseline (95% confidence interval [CI], -0.053 to -0.011; p=0.003) and between post 2 and baseline (95% CI, -0.052 to -0.009; p=0.005). No adverse events, such as burns, were observed. CONCLUSION: This study of the short-term effects of indirect moxibustion on renal hemodynamics in healthy persons showed that renal vascular resistance was reduced after the therapy.

Effect of Cydonia oblonga Mill. fruit and leaf extracts on blood pressure and blood rheology in renal hypertensive rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Quince, Cydonia oblonga Mill. (COM), is used in traditional Uyghur medicine to treat or prevent cardiovascular diseases. Uyghur people have greater longevity and lower blood pressure than other central Asian populations. We therefore tested COM fruit and leaf extracts on blood pressure and rheology in renal hypertensive rats (RHR). MATERIALS AND METHODS: Two-kidney, one-clip (2K1C) renal hypertensive rats were divided randomly into eleven groups: sham, model, and model treated with daily doses of 80 and 160mg/kg aqueous or ethanol extracts of COM fruit or leaves, or 25mg/kg captopril (n=10 per group), given orally once daily for 8 weeks. Blood pressure was measured before treatment and every 2 weeks thereafter. Blood rheology was tested after 8 weeks. RESULTS: Model rats had higher blood pressure than sham 8 weeks after the procedure (systolic blood pressure 193±7 vs. 138±8mmHg, p<0.05). Those treated with captopril had decreased blood pressure within 2 weeks but that did not return to the level found in the sham group at 8 weeks (167±7, p<0.05 vs. model). With the COM extracts, the effect on blood pressure was notable after 4 weeks. At 8 weeks blood pressure was similar with captopril and with 160mg ethanol leaf extract (166±4, p<0.05 vs. model), the most effective of the extracts. Model rats had higher blood viscosity and lower erythrocyte deformability than sham. Captopril had little effect on blood rheology; whereas COM extracts reduced whole blood viscosity and improved erythrocyte deformability to levels approaching those found in sham. CONCLUSIONS: COM extracts have antihypertensive activity in renal hypertensive rats. The additional effect on rheology, compared to captopril, may convey added interest. Further studies of these effects in man appear warranted.

Effects of chronotherapy of benazepril on the diurnal profile of RAAS and clock genes in the kidney of 5/6 nephrectomy rats.

This study investigated the effects of benazepril administered in the morning or evening on the diurnal variation of renin-angiotensin-aldosterone system (RAAS) and clock genes in the kidney. The male Wistar rat models of 5/6 subtotal nephrectomy (STNx) were established. Animals were randomly divided into 4 groups: sham STNx group (control), STNx group, morning benazepril group (MB) and evening benazepril group (EB). Benazepril was intragastrically administered at a dose of 10 mg/kg/day at 07:00 and 19:00 in the MB group and EB group respectively for 12 weeks. All the animals were synchronized to the light:dark cycle of 12:12 for 12 weeks. Systolic blood pressure (SBP), 24-h urinary protein excretion and renal function were measured at 11 weeks. Blood samples and kidneys were collected every 4 h throughout a day to detect the expression pattern of renin activity (RA), angiotensin II (AngII) and aldosterone (Ald) by radioimmunoassay (RIA) and the mRNA expression profile of clock genes (bmal1, dbp and per2) by real-time PCR at 12 weeks. Our results showed that no significant differences were noted in the SBP, 24-h urine protein excretion and renal function between the MB and EB groups. There were no significant differences in average Ald and RA content of a day between the MB group and EB group. The expression peak of bmal1 mRNA was phase-delayed by 4 to 8 h, and the diurnal variation of per2 and dbp mRNA diminished in the MB and EB groups compared with the control and STNx groups. It was concluded when the similar SBP reduction, RAAS inhibition and clock gene profile were achieved with optimal dose of benazepril, morning versus evening dosing of benazepril has the same renoprotection effects.

Chronotherapy improves blood pressure control and reduces vascular risk in CKD.

In patients with chronic kidney disease (CKD), the prevalence of increased blood pressure during sleep and blunted sleep-time-relative blood pressure decline (a nondipper pattern) is very high and increases substantially with disease severity. Elevated blood pressure during sleep is the major criterion for the diagnoses of hypertension and inadequate therapeutic ambulatory blood pressure control in these patients. Substantial, clinically meaningful ingestion-time-dependent differences in the safety, efficacy, duration of action and/or effects on the 24 h blood pressure pattern of six different classes of hypertension medications and their combinations have been substantiated. For example, bedtime ingestion of angiotensin-converting-enzyme inhibitors and angiotensin-receptor blockers is more effective than morning ingestion in reducing blood pressure during sleep and converting the 24 h blood pressure profile into a dipper pattern. We have identified a progressive reduction in blood pressure during sleep--a novel therapeutic target best achieved by ingestion of one or more hypertension medications at bedtime--as the most significant predictor of decreased cardiovascular risk in patients with and without CKD. Recent findings suggest that in patients with CKD, ambulatory blood pressure monitoring should be used for the diagnosis of hypertension and assessment of cardiovascular disease risk, and that therapeutic strategies given at bedtime rather than on awakening are preferable for the management of hypertension.

Electroacupuncture and moxibustion decrease renal sympathetic nerve activity and retard progression of renal disease in rats.

BACKGROUND/AIM: Chronic kidney disease (CKD) is an increasing major public health problem worldwide. The sympathetic nervous system and nitric oxide play an important role in the pathogenesis of CKD. Traditional Chinese medicine has accumulated thousands of years of therapeutic experiences. Electroacupuncture (EA) and moxibustion (MO) are two such therapeutic strategies. The aim of this study was to investigate the renal and hemodynamic effects of EA-MO in an experimental model of a CKD. METHODS: Male Wistar rats submitted to 5/6th nephrectomy (5/6 NX) were studied for 8 weeks. There were four groups: (1) control, normal rats; (2) NX, 5/6 NX only; (3) NX-AS, 5/6 NX and EA-MO session using sham points, and (4) NX-AM, 5/6 NX and EA-MO session using real acupoints. Biochemical and blood pressure studies, renal sympathetic nerve activity measurements, nitric oxide levels and the histopathological indices were assessed. RESULTS: The EA- and MO-treated group presented significant improvement in all measured functional and histopathological parameters. CONCLUSION: These findings suggest that EA-MO had beneficial effects on CKD. This effect was probably achieved by the modulation of the renal sympathetic nerve activity and nitric oxide levels, leading to decreased blood pressure, which is associated with less proteinuria.

Special considerations for antihypertensive agents in dialysis patients.

Hypertension is present in most patients with end-stage renal disease and likely contributes to the premature cardiovascular disease in dialysis patients. Previous practice guidelines have recommended that, in patients on chronic dialysis, blood pressure (BP) should be reduced below 130/80 mm Hg. This is based on opinions but not strong evidence, since no concrete information exists about which BP values should be the parameter to follow and which should be the target BP values. The majority of the antihypertensive agents can be used in this population, but the pharmacokinetics altered by the impaired kidney function and dialyzability influence the appropriate dosage as well as the time and frequency of administration. Combination therapy using multiple agents is often necessary. Because of the prevalence of overactivity of the renin-angiotensin-aldosterone system and sympathetic tone as well as the high calcium influx in vascular smooth muscle cells in dialysis patients, drugs acting in these three specific systems may potentially have additional cardioprotective benefits beyond their BP-lowering effect. Thus, antihypertensive regimens should preferably be based on these classes of drugs, alone or in combination. Other antihypertensive drug classes can play a complementary role.

Transient nitric oxide reduction induces permanent cardiac systolic dysfunction and worsens kidney damage in rats with chronic kidney disease.

Left ventricular systolic dysfunction (LVSD) in patients with chronic kidney disease (CKD) is associated with poorer prognosis. Because patients with CKD often exhibit progressively decreased nitric oxide (NO) availability and inhibition of NO production can reduce cardiac output, we hypothesized that loss of NO availability in CKD contributes to pathogenesis of LVSD. Subtotally nephrectomized (SNX) rats were treated with a low dose of the NO synthase inhibitor N(omega)-nitro-L-arginine (L-NNA; 20 mg/l water; SNX+L-NNA) and compared with relevant control groups. To study permanent changes separate from hemodynamic effects, L-NNA was stopped after week 8 and rats were followed up to week 15, until blood pressure was similar in SNX+L-NNA and SNX groups. To study effects of NO depletion alone, a control group with high-dose L-NNA (L-NNA-High: 100 mg/l) was included. Mild systolic dysfunction developed at week 13 after SNX. In SNX+L-NNA, systolic function decreased by almost 50% already from week 4 onward, together with markedly reduced whole body NO production and high mortality. In L-NNA-High, LVSD was not as severe as in SNX+L-NNA, and renal function was not affected. Both LVSD and NO depletion were reversible in L-NNA-High after L-NNA was stopped, but both were persistently low in SNX+L-NNA. Proteinuria increased compared with rats with SNX, and glomerulosclerosis and cardiac fibrosis were worsened. We conclude that SNX+L-NNA induced accelerated and permanent LVSD that was functionally and structurally different from CKD or NO depletion alone. Availability of NO appears to play a pivotal role in maintaining cardiac function in CKD.

Study on the relationship between blood stasis syndrome and clinical pathology in 227 patients with primary glomerular disease.

OBJECTIVE: To investigate the relationship between the severity of Chinese medicine (CM) blood stasis syndrome (BSS) with clinical features and renal lesion indexes of the primary glomerular disease. METHODS: An epidemiological survey was conducted to collect the data of 227 patients diagnosed as chronic primary glomerular diseases, and their severity of BSS were scored three days before renal biopsies were performed. The following clinical indexes were analyzed: age, course of glomerular diseases, 24-h urine protein ration (Upro), hypertension and blood pressure (BP) progress, serum creatinine levels (Scr), estimation of glomerular filtration rate based on the predigesting equation of MDRD (eGFR), blood urea nitrogen (BUN), uric acid (UA), triglyceride (TG), cholesterol (CHO), haematoglobin (HGB), albumin (ALB), and the correlation among renal pathological types, pathology lesion indexes, and BSS scores. RESULTS: (1) Among the 227 patients, 207 (91.19%) were diagnosed as BSS, in which 95 cases were considered as moderate and the rest 112 cases as severe. (2) There was a negative correlation between age, gender, grades of the hypertension, and the BSS score. Multiple stepwise regression analysis showed that Upro, CHO, TG, and eGFR were positively related to the BSS score (P<0.05). (3) The BSS score has a positive correlation with indexes of chronic renal pathology, especially the tubular atrophy and interstitial fibrosis. The severity of proliferation and glomerular sclerosis was accompanied with higher BSS scores with a significant difference (P<0.05). CONCLUSIONS: BSS is one of the most common CM syndromes among patients with the primary glomerular diseases; the BSS score has a positive correlation with Upro, CHO, TG, eGFR, as well as the index of chronic renal pathology. Based on these observations, the BSS may be used as an indicator of the development of renal diseases. Being positively diagnosed as BSS could indicate the beginning of the chronic phase of the primary glomerular diseases.

Renal complications and scleroderma renal crisis.

Scleroderma renal crisis (SRC) occurs in 5-10% of SSc patients, who may present with an abrupt onset of hypertension, acute renal failure, headaches, fevers, malaise, hypertensive retinopathy, encephalopathy and pulmonary oedema. Patients at greatest risk of developing SRC are those with diffuse cutaneous or rapidly progressive forms of SSc, and treatment with a recently commenced high dose of corticosteroid. Laboratory tests may demonstrate hypercreatinaemia, microangiopathic haemolytic anaemia (MAHA), thrombocytopaenia and hyperreninaemia. Renal crisis is also linked to a positive ANA speckled pattern, antibodies to RNA polymerase I and II, and an absence of anti-centromere antibodies. Early, aggressive treatment with angiotensin-converting enzyme inhibitors has improved prognosis in SRC, although 40% of the patients may require dialysis, and mortality at 5 yrs is 30-40%. Median time to recovery is 1 yr, and typically occurs within 3 yrs. Prognosis is worse for males, but may not be related to corticosteroid use, presence of MAHA or severity of renal pathology. Modification of endothelin over-activity, which is implicated in the pathogenesis of SRC, may offer a future therapeutic approach.

[Effects of puerarin on expression of apelin and its receptor of 2K1C renal hypertension rats].

OBJECTIVE: To examine the change of puerarin on the expression of apelin and its receptor of the two-kidney, one-clip (2K1C) rats. METHOD: Tirty male Sprague-Dawley rats were randomly divided into normal control group (C), model group (M) and puerarin group (P). The mean of carotid arterial pressure (mCAP), mean of left ventricular end diastolic pressure (LVEDP), and the weight ratio of left ventricular mass (left ventricle plus septum) to bodyweight (LVM/BW) were measured to evaluate the model of 2K1C renal hypertension. The concentrations of apelin in the plasma and left ventricle (LV) were measured with radioimmunoassay. Apelin mRNA and APJ mRNA expressed in the LV were examined by reverse transcription-polymerase chain reaction (RT-PCR). The peptides of apelin and APJ expressed in the LV were detected with immunohistochemistry (IHC). RESULT: Compared with C group, the mCAP, LVEDP and LVM/BW of M group were higher 36.58%, 333.8% and 20.24%, respectively (P<0.05, P<0.01, P<0.01). Compared with M group, LVEDP and LVM/BW of P group were lower 65.24% and 13.12%, respectively (both P<0.05). However mCAP was of no significant difference between these two groups. The levels of apelin-36 in the plasma and LV of M group were respectively higher 18.56% and 207.38% than those of C group (both P<0.05), while ones of P group were lower 24.21% and 49.40% than those of M group (both P<0.05). The expressions of apelin mRNA and APJ mRNA at left ventricle tissues of 2K1C rats were higher 77.66% and 119.00% (both P<0.05) than those of C group. The ones of P group were lower 27.40% and 45.66% than those of M group (both P<0.01). The IHC results indicate that the expressions of apelin and APJ peptides at left ventricle tissues of 2K1C rats were higher 129.51% and 154.1% (both P<0.01) than those of C group, respectively. Whereas the ones of P group were lower 65.36% and 62.87% than those of M group (both P<0.01). CONCLUSION: Through regulating apelin/APJ system puerarin has protective effect on the development of left ventricular hypertrophy by renal hypertension.

Endogenous melanocortin system activity contributes to the elevated arterial pressure in spontaneously hypertensive rats.

Previous studies suggest that activation of the CNS melanocortin system reduces appetite while increasing sympathetic activity and arterial pressure. The present study tested whether endogenous activity of the CNS melanocortin 3/4 receptors (MC3/4-R) contributes to elevated arterial pressure in the spontaneously hypertensive rat (SHR), a model of hypertension with increased sympathetic activity. A cannula was placed in the lateral ventricle of male SHR and Wistar (WKY) rats for chronic intracerebroventricular (ICV) infusions (0.5 muL/h). Mean arterial pressure (MAP) and heart rate (HR) were recorded 24 hour/d using telemetry. After 5-day control period, rats were infused with MC3/4-R antagonist (SHU-9119, 1 nmol/h-ICV) for 12 days, followed by 5-day posttreatment period. MC3/4-R antagonism increased food intake in SHR by 90% and in WKY by 125%, resulting in marked weight gain, insulin resistance, and hyperleptinemia in SHR and WKY. Despite weight gain, MC3/4-R antagonism reduced HR in SHR and WKY ( approximately 40 bpm), while lowering MAP to a greater extent in SHR (-22+/-4 mm Hg) than WKY (-4+/-3 mm Hg). SHU9119 treatment failed to cause further reductions in MAP during chronic adrenergic blockade with propranolol and terazosin. These results suggest that endogenous activity of the CNS melanocortin system contributes to the maintenance of adrenergic tone and elevated arterial pressure in SHR even though mRNA levels for POMC and MC4R in the mediobasal hypothalamus were not increased compared to WKY. These results also support the hypothesis that weight gain does not raise arterial pressure in the absence of a functional MC3/4-R.

Circadian blood pressure variation and antihypertensive medication adjustment in normoalbuminuric type 2 diabetes patients.

BACKGROUND/AIMS: The aim of the study was to assess the effect of an antihypertensive treatment adjustment on 24-hour blood pressure variation in type 2 diabetes patients. METHODS: The study group included 59 hypertensive type 2 diabetes patients subjected to a single one-step antihypertensive agent dose adjustment (increase or decrease). Ambulatory blood pressure monitoring was performed at baseline and 4-6 weeks after the treatment modification. Controls were 41 matched patients, in whom antihypertensive treatment remained unchanged. RESULTS: At baseline, 45 (76%) study group patients and 29 (71%) controls were 'non-dippers'; a similar number of patients in both groups converted to 'dipping' or vice versa: 11 (19%) from the study group and 7 (17%) controls. 'Converters' from the study group were significantly younger (47.5 +/- 3.9 vs. 56.4 +/- 12.2 years; p < 0.05) and had lower 24-hour systolic blood pressure than 'non-converters': 113.7 +/- 7.2 vs. 127.7 +/- 20.3 mm Hg (p < 0.01). CONCLUSION: A single one-step antihypertensive medication adjustment does not affect 'dipping' status in type 2 diabetes patients. However, the assessment of blood pressure variation should be made with greater caution in younger type 2 diabetes subjects with low systolic blood pressure.

An open-label, randomized, controlled, 4-week comparative clinical trial of barnidipine hydrochloride, a calcium-channel blocker, and benazepril, an angiotensin-converting enzyme inhibitor, in Chinese patients with renal parenchymal hypertension.

This study compared barnidipine, a calcium-channel blocker, and benazepril, an angiotensin-converting enzyme inhibitor, in 85 Chinese patients with renal parenchymal hypertension (diastolic blood pressure range 95 - 110 mmHg). Patients were randomly assigned to receive either 10 mg barnidipine or 10 mg benazepril orally daily for 4 weeks. In patients with diastolic blood pressure > 90 mmHg after 2 weeks of treatment, the dose of barnidipine or benazepril was increased by 5 or 10 mg, respectively. Both the barnidipine-treated group (n = 43) and the benazepril-treated group (n = 42) showed significant mean reductions from baseline in sitting systolic and diastolic blood pressures. The decrease in diastolic blood pressure with benazepril was significantly greater than with barnidipine treatment. Sitting heart rate was not changed by either drug. There was no significant difference in adverse events between the two groups. Barnidipine is similar to benazepril for the treatment of renal parenchymal hypertension.

Nitric oxide mediates the blood-pressure lowering effect of garlic in the rat two-kidney, one-clip model of hypertension.

Garlic reduces blood pressure (BP) in two-kidney, one-clip (2K-1C) rats, and enhances nitric oxide (NO) synthesis in in vivo and in vitro experiments. NO is an important modulator of BP in the 2K-1C model. This study investigated the role of NO in the BP-lowering effect of garlic in the 2K-1C model. BP readings (mm Hg) were obtained from 2K-1C rats in 4 groups treated intraperitoneally for 2 wk with either normal saline (NS), garlic, L-nitroarginine-methylester (L-NAME), or L-NAME+garlic (n=4x5). BP was determined using the tail-cuff method and compared with data of 4 similarly treated groups of normal (unclipped) rats (NRs). The BP readings of NR groups were 120+/-3 mm Hg for the NS-treated group, 120+/-2 mm Hg for the garlic-treated group, 167+/-3 mm Hg for the L-NAME treated group (higher than NS or garlic, P<0.001) and 128+/-5 mm Hg for the garlic+L-NAME-treated group (lower than L-NAME, P<0.001). The BP readings of 2K-1C rat groups were: for the NS group, 169+/-6 mm Hg (higher than NRs, P<0.001); for the garlic group, 116+/-7 mm Hg (lower than NS, P<0.001); for the L-NAME group: 184+/-8 mm Hg (higher than garlic, P<0.001), and for the L-NAME+garlic group: 130+/-6 mm Hg (lower than garlic or NS, P<0.001). The data show that L-NAME increases the BP of both NRs and 2K-1C rats, with the rise more evident in the NRs (39 vs. 9%, respectively). Garlic counteracts the hypertensive effect of L-NAME in NRs as well as 2K-1C rats. We conclude that the BP-lowering effect of garlic in the rat 2K-1C model may be partly mediated through the NO pathway.

Programming blood pressure in adult SHR by shifting perinatal balance of NO and reactive oxygen species toward NO: the inverted Barker phenomenon.

The "programming hypothesis" proposes that an adverse perinatal milieu leads to adaptation that translates into cardiovascular disease in adulthood. The balance between nitric oxide (NO) and reactive oxygen species (ROS) is disturbed in cardiovascular diseases, including hypertension. Conceivably, this balance is also disturbed in pregnancy, altering the fetal environment; however, effects of perinatal manipulation of NO and ROS on adult blood pressure (BP) are unknown. In spontaneously hypertensive rats (SHR), NO availability is decreased and ROS are increased compared with normotensive Wistar-Kyoto rats, and, despite the genetic predisposition, the perinatal environment can modulate adult BP. Our hypothesis is that a disturbed NO-ROS balance in the SHR dam persistently affects BP in her offspring. Dietary supplements, which support NO formation and scavenge ROS, administered during pregnancy and lactation resulted in persistently lower BP for up to 48 wk in SHR offspring. The NO donor molsidomine and the superoxide dismutase mimic tempol-induced comparable effects. Specific inhibition of inducible nitric oxide synthase (NOS) reduces BP in adult SHR, suggesting that inducible NOS is predominantly a source of ROS in SHR. Indeed, inducible NOS inhibition in SHR dams persistently reduced BP in adult offspring. Persistent reductions in BP were accompanied by prevention of proteinuria in aged SHR. We propose that in SHR the known increase in ANG II type 1 receptor density during development leads to superoxide production, which enhances inducible NOS activity. The relative shortage of substrate and cofactors leads to uncoupling of inducible NOS, resulting in superoxide production, activating transcription factors that subsequently again increase inducible NOS expression. This vicious circle probably is perpetuated into adult life.