Assessment of Hypokalemia and Clinical Characteristics in Patients With Coronavirus Disease 2019 in Wenzhou, China.

Importance: Severe acute respiratory syndrome coronavirus 2 has caused a global outbreak of coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 binds angiotensin-converting enzyme 2 of the rennin-angiotensin system, resulting in hypokalemia. Objective: To investigate the prevalence, causes, and clinical implications of hypokalemia, including its possible association with treatment outcomes, among patients with COVID-19. Design, Setting, and Participants: This cohort study was conducted at Wenzhou Central Hospital and Sixth People's Hospital of Wenzhou, Wenzhou, China, from January 11, 2020, to February 15, 2020. Participants included patients who received a diagnosis of COVID-19 according to the criteria issued by the Chinese Health Bureau and were admitted to the hospital. The patients were classified as having severe hypokalemia (plasma potassium <3 mmol/L), hypokalemia (plasma potassium 3-3.5 mmol/L), and normokalemia (plasma potassium >3.5 mmol/L). The clinical features, therapy, and outcomes were compared between the 3 groups. Data analysis was conducted in March 2020. Interventions: The patients were given general support and antiviral therapy. Their epidemiological and clinical features were collected. Main Outcomes and Measures: The prevalence of hypokalemia and response to treatment with potassium supplements were measured by analyzing plasma and urine potassium levels. Results: One hundred seventy-five patients (87 female patients [50%]; mean [SD] age, 45 [14] years) were classified as having severe hypokalemia (31 patients [18%]), hypokalemia (64 patients [37%]), and normokalemia (80 patients [46%]). Patients with severe hypokalemia had statistically significantly higher body temperature (mean [SD], 37.6 °C [0.9 °C]) than the patients with hypokalemia (mean [SD], 37.2 °C [0.7 °C]; difference, 0.4 °C; 95% CI, 0.2-0.6 °C; P = .02) and the patients with normokalemia (mean [SD], 37.1 °C [0.8 °C]; difference, 0.5 °C; 95% CI, 0.3-0.7 °C; P = .005). Patients with higher levels of hypokalemia also had higher creatine kinase levels (severe hypokalemia, mean [SD], 200 [257] U/L [median, 113 U/L; interquartile range {IQR}, 61-242 U/L]; hypokalemia, mean [SD], 97 [85] U/L; and normokalemia, mean [SD], 82 [57] U/L), higher creatine kinase-MB fraction (severe hypokalemia, mean [SD], 32 [39] U/L [median, 14 U/L; IQR, 11-36 U/L]; hypokalemia, mean [SD], 18 [15] U/L; and normokalemia, mean [SD], 15 [8] U/L), higher lactate dehydrogenase levels (mean [SD], severe hypokalemia, 256 [88] U/L; hypokalemia, 212 [59] U/L; and normokalemia, 199 [61] U/L), and higher C-reactive protein levels (severe hypokalemia, mean [SD], 29 [23] mg/L; hypokalemia, mean [SD], 18 [20] mg/L [median, 12, mg/L; IQR, 4-25 mg/L]; and normokalemia, mean [SD], 15 [18] mg/L [median, 6 U/L; IQR, 3-17 U/L]). Of 40 severely and critically ill patients, 34 (85%) had hypokalemia. Patients with severe hypokalemia were given potassium at a dose of 40 mEq per day, for a total mean (SD) of 453 (53) mEq potassium chloride, during the hospital stay. The patients responded well to potassium supplements as they recovered. Conclusions and Relevance: The correction of hypokalemia is challenging because of continuous renal potassium loss resulting from the degradation of angiotensin-converting enzyme 2. The high prevalence of hypokalemia among patients with COVID-19 suggests the presence of disordered rennin-angiotensin system activity, which increases as a result of reduced counteractivity of angiotensin-converting enzyme 2, which is bound by severe acute respiratory syndrome coronavirus 2.

A Dimorphic Diagnosis of a Pleomorphic Disease: An Unusual Cause of Hypercalcemia.

BACKGROUND: Histoplasmosis is a rare cause of 1, 25-dihydroxy vitamin-D-mediated hypercalcemia. In this study, we report 2 cases of hypercalcemia secondary to histoplasmosis seen at Mayo Clinic, Rochester and a review of cases reported in the literature. METHODS: We conducted a PubMed search using the keywords "hypercalcemia" and "histoplasmosis." Fourteen cases of hypercalcemia secondary to histoplasmosis were reported between 1977 and 2020. We identified an additional 2 patients from our institution. RESULTS: We reviewed a total of 16 cases. The median age at presentation was 58.5 years (interquartile range, 41.5-68.75 years), and 13 of 16 patients (81.2%) were men. Serum parathyroid hormone level was available in 13 of 16 (81.25%) patients, of whom 11 patients (84.6%) had a low level, 1 patient (7.6%) had a normal level, and 1 patient (7.6%) had an elevated level. 1, 25-dihydroxy vitamin D level was reported in 9 of 16 (56.25%) patients. Of these, 5 patients (55.5%) had levels within normal limits, and 4 patients (44.4%) had levels above normal. Serum angiotensin-converting enzyme level was evaluated in 4 of 16 patients (25%), and it was elevated in all 4 (100%) cases. Four patients received corticosteroids before a diagnosis of histoplasmosis was made, which resulted in rapidly progressive disease and death in 2 patients. CONCLUSIONS: In patients with granulomatous disorder and hypercalcemia, it is crucial to rule out infectious etiologies before initiating steroids. Histoplasmosis can cause nonparathyroid hormone-mediated hypercalcemia and, if not suspected, may have catastrophic implications.

The Cyclitol L-(+)-Bornesitol as an Active Marker for the Cardiovascular Activity of the Brazilian Medicinal Plant Hancornia speciosa.

The cyclitol bornesitol is the main constituent of the leaves from the antihypertensive medicinal plant Hancornia speciosa. This study aimed to investigate the ability of bornesitol to reduce blood pressure and its mechanism of action. Normotensive Wistar rats were divided into control group and bornesitol groups treated intravenously with bornesitol (0.1, 1.0 and 3.0 mg/kg). Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded in non-anesthetized awake animals. Nitric oxide (NO) and angiotensin-converting enzyme (ACE) were measured in plasma by using colorimetric methods. Vascular reactivity study was performed in rat aorta rings and the involvement of nitric oxide synthase (NOS), calcium-calmodulin complex and phosphatidylinositol-3-kinase (PI3K)/Akt pathway in the vasodilator effect was investigated. Administration of bornesitol significantly reduced the SBP, increased the plasmatic level of nitrite, and decreased ACE activity in normotensive rats. In the rat aorta, bornesitol induced endothelium-dependent vasodilatation, which was abolished by NOS blockade. While calcium-calmodulin complex inhibition decreased the vasodilator effect of bornesitol, the inhibition of PI3K/Akt pathway did not alter it. Bornesitol reduced the blood pressure by a mechanism involving an increased production or bioavailability of NO, inhibition of ACE, and by an endothelium- and NO-dependent vasodilator effect. The present results support the use of bornesitol as an active marker for the cardiovascular activity of Hancornia speciosa.

Dipeptidyl peptidase-4 inhibitors can inhibit angiotensin converting enzyme.

Angiotensin-1 converting enzyme inhibitors (ACEIs) improve insulin sensitivity. Inhibitors of dipeptidyl peptidase-4 (DPP-4) are anti-diabetic drugs with several cardio-renal effects. Both ACE and DPP-4 share common features. Thus, we tested if they could be inhibited by one inhibitor. First, in silico screening was used to investigate the ability of different DPP-4 inhibitors or ACEIs to interact with DPP-4 and ACE. The results of screening were then extrapolated into animal study. Fifty Sprague Dawley rats were randomly assigned into 5 groups treated with vehicle, captopril, enalapril, linagliptin or sitagliptin. Both low and high doses of each drug were tested. Baseline blood samples and samples at days 1, 8, 10, 14 were used to measure plasma DPP-4 and ACE activities and angiotensin II levels. Active glucagon-like peptide-1 (GLP-1) levels were measured after oral glucose challenge. All tested DPP-4 inhibitors could interact with ACE at a relatively reasonable binding energy while most of the ACEIs only interacted with DPP-4 at a predicted high inhibition constant. In rats, high dose of sitagliptin was able to inhibit ACE activity and reduce angiotensin II levels while linagliptin had only a mild effect. ACEIs did not significantly affect DPP-4 activity or prevent GLP-1 degradation. It seems that some DPP-4 inhibitors could inhibit ACE and this could partially explain the cardio-renal effects of these drugs. Further studies are required to determine if such inhibition could take place in clinical settings.

Encapsulated Mulberry Fruit Extract Alleviates Changes in an Animal Model of Menopause with Metabolic Syndrome.

Currently, the therapeutic strategy against metabolic syndrome and its complications is required due to the increasing prevalence and its impact. Due to the benefits of both mulberry fruit extract and encapsulation technology, we hypothesized that encapsulated mulberry fruit extract (MME) could improve metabolic parameters and its complication risk in postmenopausal metabolic syndrome. To test this hypothesis, female Wistar rats were induced experimental menopause with metabolic syndrome by bilateral ovariectomy (OVX) and high-carbohydrate high-fat (HCHF) diet. Then, they were orally given MME at doses of 10, 50, and 250 mg/kg BW for 8 weeks and the parameters, such as percentage of body weight gain, total cholesterol, triglycerides, HDL-C, LDL-C, atherogenic index, fasting blood glucose, plasma glucose area under the curve, serum angiotensin-converting enzyme (ACE), oxidative stress status, histology, and protein expression of PPAR-γ, TNF-α, and NF-κB in adipose tissues were determined. MME improved body weight gain, adiposity index, glucose intolerance, lipid profiles, atherogenic index, ACE, oxidative stress status, and protein expression of TNF-α and NF-κB. Moreover, MME attenuated adipocyte hypertrophy and enhanced PPAR-γ expression. Taken altogether, MME decreased metabolic syndrome and its complication via the increased PPAR-γ expression. Therefore, MME is the potential candidate for improving metabolic syndrome and its related complications. However, further research in clinical trial is still necessary.

Diuretic herb Gomphrena celosioides Mart. (Amaranthaceae) promotes sustained arterial pressure reduction and protection from cardiac remodeling on rats with renovascular hypertension.

ETHNOPHARMACOLOGICAL RELEVANCE: Gomphrena celosioides Mart., belonging to the Amaranthaceae family, is a weed known as "perpétua," and its ethnopharmacological use is to treat of urinary tract disorders and kidney stones. Urinary tract disorders and kidney stones could include several pathological conditions such hypertension, diuretic and lithiasic problems. In the present work a model of renovascular hypertension was developed in vivo to investigate its usefulness as an antihypertensive drug. AIM OF THE STUDY: Evaluate the effect of acute and 28 day oral administration of G. celosioides extract on systemic arterial pressure and diuresis of renovascular-hypertensive rats, as well as its effect on cardiac remodeling and vascular reactivity. MATERIALS AND METHODS: Ethanolic extract of G. celosioides (EEGC) was used. To induce renovascular hypertension, adult male Wistar rats were submitted to Goldblatt 1K1C or 2K1C surgery. The mean arterial pressure (MAP) of 1K1C animals was directly assessed by cannulation of the carotid artery before and after intraduodenal acute administration of 30, 100 or 300 mg/kg of EEGC. For the 4-week assay, 2K1C animals received daily treatments with water (control group), 100 mg/kg EEGC or 15 mg/kg enalapril for 28 days. Diuresis and caudal blood pressure were assessed weekly, and at the 28th day of treatment, the MAP was directly quantified shortly before euthanasia. Internal organs were removed, weighed and routinely processed for histology and the left ventricle wall was measured. Blood was collected for biochemical analysis and mechanism investigation by quantification of angiotensin converting enzyme (ACE) activity and aldosterone, nitrite and thiobarbituric acid reactive substances (TBARS) concentration. The rats' mesenteric beds were isolated and cannulated to have their pressure variation assessed after crescent doses of phenylephrine (Phe), acetylcholine (ACh) and sodium nitroprusside (SNP). RESULTS: EEGC acutely reduced MAP the dose of 100 mg/kg. In the 4-week assay, EEGC acted as diuretic after acute administration after 1, 2, 3 and 4 weeks of treatment. EEGC also acted as an antihypertensive and it showed significant difference already after 1 week (and after 3 and 4 weeks) compared to control, with its MAP close to pre-surgery values at the end of the experiment. It promoted ACE inhibition, which led to lower aldosterone levels. The lower TBARS and higher nitrite concentration found in the EEGC group suggest antioxidant activity and NO maintenance. Moreover, EEGC counteracted the impairment of vascular reactivity induced by renovascular hypertension. The extract group presented thinner left ventricle wall compared to the control, meaning reduced hypertension-induced cardiac remodeling. CONCLUSIONS: The G. celosioides diuretic effect is maintained on renovascular hypertensive rats and can reduce the blood pressure after the first week of treatment by inhibiting ACE and these effects are longstanding and strong enough to promote protection against cardiac remodeling. Therefore, it shows potential as an antihypertensive drug.

Protective Effect of Polyphenol-Rich Extract from Bee Pollen in a High-Fat Diet.

We have studied a preventive effect of polyphenol-rich bee pollen ethanol extract (EEP) against histological changes in the liver and cardiac blood vessels, abnormalities of lipid profile, and the levels of oxidized low density lipoproteins (ox-LDL), asymmetric dimethylarginine (ADMA), angiotensin-converting enzyme (ACE), and angiotensin II (ANG II) caused by a high-fat diet in C57BL6 mice. Supplementing the diet with EEP in the doses of 0.1 g/kg body mass (BM) and 1 g/kg BM resulted in a decrease of total cholesterol by 31% and 35%, respectively. It also decreased the level of low density lipoproteins by 67% and 90%, respectively. No differences in the levels of high density lipoprotein and triacylglycerols were observed. EEP reduced the level of ox-LDL by 33% and 47%, ADMA by 13% and 51%, ACE by 17% and 30%, as well as ANG II by 11% and 15% in a dose-dependent manner, which proves a protective effect of EEP in a high-fat diet. EEP reduces and/or prevents hepatic steatosis and degenerative changes caused by a high-fat diet in C57BL6 mice, which indicates its hepatoprotective effect. EEP used with standard feed does not disturb a normal concentration of the assayed parameters.

Efficacy and safety of infliximab biosimilar Inflectra® in severe sarcoidosis.

BACKGROUND: Infliximab, a monoclonal antibody against tumor necrosis factor alpha (TNF-α) is effective third-line therapy in severe sarcoidosis. The originator product of Infliximab, Remicade®, is expensive, limiting universal access. Recently, a less expensive biosimilar of infliximab, Inflectra®, has become available, but the efficacy and tolerability has not been studied in sarcoidosis. METHODS: In this retrospective cohort study, 29 patients treated with the infliximab biosimilar Inflectra®, were analysed. Patients received Inflectra® intravenously monthly at a dose of 5 mg/kg. We measured trough levels before every infusion. Before and after 6 months of induction therapy pulmonary function and disease activity were evaluated using Standardised Uptake Value (SUV) of the 18F-fluorodeoxyglucose by positron emission tomography (18F-FDG PET), soluble interleukin-2 receptor (sIL-2R), angiotensin converting enzyme (ACE) and health-related quality of life (HRQOL). RESULTS: In patients with pulmonary sarcoidosis as main treatment indication (n = 15) the predicted FVC improved with 8.1%, p < 0.05. Furthermore, in the whole group HRQoL improved significantly (p < 0.001), whereas SUVmax and sIL-2R significantly reduced (p < 0.001 and p = 0.001 respectively). Hospitalisation due to infections occurred in four patients. None of the patients discontinued Inflectra® due to side-effects. Furthermore, all patients had detectable trough levels indicating development of neutralizing antibodies. CONCLUSION: Infliximab biosimilar Inflectra® seems effective in the treatment of refractory sarcoidosis with a comparable safety profile to the reference product Remicade®. Inflectra® can be considered as an alternative and less expensive option for patients with refractory sarcoidosis.

Purification of angiotensin-converting enzyme from human plasma and investigation of the effect of some active ingredients isolated from Nigella sativa L. extract on the enzyme activity.

In the present study, one-step purification of angiotensin-converting enzyme (ACE, peptidyldipeptidase A, EC 3.4.15.1), responsible for regulation of blood pressure, was achieved using affinity chromatography from human plasma. The enzyme was purified 12,860-fold with a specific activtiy of 5080 EU/mg protein. Optimum temperature and pH were determined for the enzyme as 35-40°C and pH 7.4-7.5, respectively. The purity of ACE was determined by SDS-PAGE and the enzyme showed two bands at 60 and 70 kDa on the gel. The native molecular weight of ACE was found to be 260 kDa by gel filtration chromatography, demonstrating that the enzyme has a heterodimeric structure. Natural fatty acids of Nigella sativa (Ranunculaceae) were isolated by means of column chromatography. The structures of these compounds were determined using NMR and GC-MS. The results showed that high concentrations of linoleic, oleic and palmitic acids were isolated from the plant. The effect of six fractions (Fr 1-6) on ACE activity was examined. Fraction 3 increased the ACE activity while the other fractions decreased the enzyme activity. The concentrations of the fractions inhibiting the half-maximum activity of the enzyme were calculated as 1.597 mg/mL for Fr 1, 0.053 mg/mL for Fr 2, 0.527 mg/mL for Fr 4, 0.044 mg/mL for Fr 5 and 0.136 mg/mL for Fr 6 using a Lineweaver-Burk graph.

Changes in angiotensin II and angiotensin-converting enzyme of different tissues after prolonged hyperoxia exposure.

Current study findings concerning changes in the renin-angiotensin system (RAS) in cases of hyperoxic acute lung injury (HALI) have shown conflicting results. This study aimed to detect the angiotensin II (Ang II) and angiotensin-converting enzyme (ACE) in a rat HALI model. Healthy male Sprague-Dawley rats were randomly assigned into three groups: the control group, HALI group and hyperbaric oxygen preconditioning (HBO2-PC) group. HALI was induced by exposure to pure oxygen at 250 kPa for six hours. In the HBO2-PC group, rats were exposed to oxygen at 250 kPa for 60 minutes twice daily for two consecutive days; HALI was induced at 24 hours after the last oxygen exposure.=After HALI, the lung, spleen and liver were harvested for HE staining and pathological examination. At one hour and 18 hours after HALI, the blood, liver, lung and spleen were collected for the detection of Ang II and ACE contents by enzyme-linked immunosorbent assay. Pathological examination showed the lung was significantly damaged and characteristics of HALI were observed, but there were no significant pathological changes in the liver and spleen. After HALI, Ang II and ACE contents of different tissues increased progressively over time, but the HBO2-PC group showed reductions in the Ang II and ACE contents to a certain extent, especially at 18 hours after injury. These findings suggest prolonged hyperoxia exposure may activate the RAS, which may be associated with the pathogenesis of HALI. HBO2-PC has a limited capability to inhibit RAS activation.

Effect of foxtail millet protein hydrolysates on lowering blood pressure in spontaneously hypertensive rats.

PURPOSE: The objective of this study was to determine the effect of foxtail millet protein hydrolysates on lowering blood pressure in spontaneously hypertensive rats (SHRs). METHODS: The protein of foxtail millet after extruding or fermenting and the raw foxtail millet was extracted and hydrolyzed by digestive protease to generate angiotensin-converting enzyme (ACE) inhibitory peptides. The potential antihypertensive effect of protein hydrolysates from foxtail millet in SHRs was investigated. RESULTS: After 4 weeks of treatment with 200 mg peptides/kg of body weight of protein hydrolysates, blood pressure was lowered significantly, and the raw and extruded samples were more effective than the fermented samples. The serum ACE activity and angiotensin II levels in the treatment groups were significantly lower than that of the control. The percent heart weight decreased in the treatment groups. CONCLUSION: Thus, ingestion of foxtail millet protein hydrolysates especially for the raw and extruded hydrolysates may ameliorate hypertension and alleviate related cardiovascular diseases.

Angiotensin converting enzyme 2 activity and human atrial fibrillation: increased plasma angiotensin converting enzyme 2 activity is associated with atrial fibrillation and more advanced left atrial structural remodelling.

AIM: Angiotensin converting enzyme 2 (ACE2) is an integral membrane protein whose main action is to degrade angiotensin II. Plasma ACE2 activity is increased in various cardiovascular diseases. We aimed to determine the relationship between plasma ACE2 activity and human atrial fibrillation (AF), and in particular its relationship to left atrial (LA) structural remodelling. METHODS AND RESULTS: One hundred and three participants from a tertiary arrhythmia centre, including 58 with paroxysmal AF (PAF), 20 with persistent AF (PersAF), and 25 controls, underwent clinical evaluation, echocardiographic analysis, and measurement of plasma ACE2 activity. A subgroup of 20 participants underwent invasive LA electroanatomic mapping. Plasma ACE2 activity levels were increased in AF [control 13.3 (9.5-22.3) pmol/min/mL; PAF 16.9 (9.7-27.3) pmol/min/mL; PersAF 22.8 (13.7-33.4) pmol/min/mL, P = 0.006]. Elevated plasma ACE2 was associated with older age, male gender, hypertension and vascular disease, elevated left ventricular (LV) mass, impaired LV diastolic function and advanced atrial disease (P < 0.05 for all). Independent predictors of elevated plasma ACE2 activity were AF (P = 0.04) and vascular disease (P < 0.01). There was a significant relationship between elevated ACE2 activity and low mean LA bipolar voltage (adjusted R2 = 0.22, P = 0.03), a high proportion of complex fractionated electrograms (R2 = 0.32, P = 0.009) and a long LA activation time (R2 = 0.20, P = 0.04). CONCLUSION: Plasma ACE2 activity is elevated in human AF. Both AF and vascular disease predict elevated plasma ACE2 activity, and elevated plasma ACE2 is significantly associated with more advanced LA structural remodelling.

Impact of chronic administration of anabolic androgenic steroids and taurine on blood pressure in rats.

Supraphysiological administration of anabolic androgenic steroids has been linked to increased blood pressure. The widely distributed amino acid taurine seems to be an effective depressor agent in drug-induced hypertension. The purpose of this study was to assess the impact of chronic high dose administration of nandrolone decanoate (DECA) and taurine on blood pressure in rats and to verify the potentially involved mechanisms. The study was conducted in 4 groups of 8 adult male Wistar rats, aged 14 weeks, treated for 12 weeks with: DECA (A group); vehicle (C group); taurine (T group), or with both drugs (AT group). Systolic blood pressure (SBP) was measured at the beginning of the study (SBP1), 2 (SBP2) and 3 months (SBP3) later. Plasma angiotensin-converting enzyme (ACE) activity and plasma end products of nitric oxide metabolism (NOx) were also determined. SBP3 and SBP2 were significantly increased compared to SBP1 only in the A group (P<0.002 for both). SBP2, SBP3 and ACE activity showed a statistically significant increase in the A vs C (P<0.005), andvs AT groups (P<0.05), while NOx was significantly decreased in the A and AT groups vs controls (P=0.01). ACE activity was strongly correlated with SBP3 in the A group (r=0.71, P=0.04). These findings suggest that oral supplementation of taurine may prevent the increase in SBP induced by DECA, an effect potentially mediated by angiotensin-converting enzyme.

Potential Therapeutic Applications of Mucuna pruriens Peptide Fractions Purified by High-Performance Liquid Chromatography as Angiotensin-Converting Enzyme Inhibitors, Antioxidants, Antithrombotic and Hypocholesterolemic Agents.

A Mucuna pruriens protein concentrate was hydrolyzed with a digestive (pepsin-pancreatin) enzymatic system. The soluble portion of the hydrolysate was fractionated by ultrafiltration and the ultrafiltered peptide fraction (PF) with lower molecular weight was purified by reversed-phase high-performance liquid chromatography. The PF obtained were evaluated by testing the biological activity in vitro. Fractions showed that the ability to inhibit the angiotensin-converting enzyme had IC50 values that ranged from 2.7 to 6.2 µg/mL. Trolox equivalent antioxidant capacity values ranged from 132.20 to 507.43 mM/mg. The inhibition of human platelet aggregation ranged from 1.59% to 11.11%, and the inhibition of cholesterol micellar solubility ranged from 0.24% to 0.47%. Hydrophobicity, size, and amino acid sequence could be factors in determining the biological activity of peptides contained in fractions. This is the first report that M. pruriens peptides act as antihypertensives, antioxidants, and inhibitors for human platelet aggregation and cholesterol micellar solubility in vitro.

Effects of Rubus occidentalis extract on blood pressure in patients with prehypertension: Randomized, double-blinded, placebo-controlled clinical trial.

OBJECTIVE: Black raspberry (Rubus occidentalis) is known for improving vascular function. However, there has been no study evaluating its effects on 24-h systolic and diastolic blood pressure in prehypertensive patients. The aim of this study was to examine those effects. METHODS: Patients with prehypertension (N = 45) were prospectively randomized into a moderate-dose black raspberry group (n = 15, 1500 mg/d), a high-dose black raspberry group (n = 15, 2500 mg/d), or a placebo group (n = 15) during an 8-wk follow-up period. Raspberries were consumed in the form of a dried powder extract that was fashioned into capsules. The capsules contained 187.5 and 312.5 mg of raspberry powder, which was equivalent to 1500 and 2500 mg raspberries. Ambulatory 24-h blood pressure (BP); central BP; pulse-wave velocity; abdominal visceral fat; serum renin; angiotensin-converting enzyme; and inflammatory cytokines such as interleukin-6, tumor necrosis factor-α, C-reactive protein, soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, and plasminogen activator inhibitor-1 were measured at baseline and at 8-wk follow-up. RESULTS: High-dose black raspberry significantly reduced 24-h systolic blood pressure (SBP; 3.3 ± 10 mm Hg versus -6.7 ± 11.8 mm Hg; P < 0.05) and nighttime SBP (5.4 ± 10.6 mm Hg versus -4.5 ± 11.3 mm Hg; P < 0.05) compared with controls during the 8-wk follow-up. Black raspberry powder did not produce any significant changes in most of the parameters other than BP. CONCLUSION: The use of black raspberry significantly lowered 24-h BP in prehypertensive patients during the 8-wk follow-up. Black raspberry used as a dietary supplement could be beneficial in reducing SBP in prehypertensive patients.

A Novel ACE Inhibitory Peptide Ala-His-Leu-Leu Lowering Blood Pressure in Spontaneously Hypertensive Rats.

Ala-His-Leu-Leu (AHLL) was isolated and purified from the loach (Misgurnus anguillicaudatus) hydrolysate in our previous study. The aim of this study was to investigate the antihypertensive effects of angiotensin-I-converting enzyme (ACE) inhibitory peptide AHLL in spontaneously hypertensive rats (SHRs). AHLL showed good antihypertensive effects in SHRs during the long-term oral administration and no allergic reactions or coughing were observed. After 2 months of oral administration of AHLL, the body weight growth was normal. The decrements in systolic blood pressure of the high dose (5 mg/kg bw) and the low dose of AHLL (1 mg/kg bw) treatment groups were 22.1 and 5.0 mmHg at week 8, respectively. Compared to the control group, the concentrations of triglyceride and sodium in serum were reduced significantly in the high-dose group after 2 months. The ACE activity of kidney and lung decreased significantly, which indicated that AHLL exerted an antihypertensive effect on kidney and lung and they were the target sites of AHLL. These results strongly supported the in vivo antihypertensive mechanism of AHLL.

Paricalcitol modulates ACE2 shedding and renal ADAM17 in NOD mice beyond proteinuria.

Circulating and renal activity of angiotensin-converting enzyme 2 (ACE2) is increased in non-obese diabetic (NOD) mice. Because paricalcitol has been reported to protect against diabetic nephropathy, we investigated the role of paricalcitol in modulating ACE2 in these mice. In addition, renal ADAM17, a metalloprotease implied in ACE2 shedding, was assessed. NOD female and non-diabetic control mice were studied for 21 days after diabetes onset and divided into various treatment groups. Diabetic animals received either vehicle; 0.4 or 0.8 µg/kg paricalcitol, aliskiren, or a combination of paricalcitol and aliskiren. We then studied the effect of paricalcitol on ACE2 expression in proximal tubular epithelial cells. Paricalcitol alone or in combination with aliskiren resulted in significantly reduced circulating ACE2 activity in NOD mice but there were no changes in urinary albumin excretion. Serum renin activity was significantly decreased in mice that received aliskiren but no effect was found when paricalcitol was used alone. Renal content of ADAM17 was significantly decreased in animals that received a high dose of paricalcitol. Renal and circulating oxidative stress (quantified by plasma H2O2 levels and immunolocalization of nitrotyrosine) were reduced in high-dose paricalcitol-treated mice compared with non-treated diabetic mice. In culture, paricalcitol incubation resulted in a significant increase in ACE2 expression compared with nontreated cells. In NOD mice with type 1 diabetes, paricalcitol modulates ACE2 activity, ADAM17, and oxidative stress renal content independently from the glycemic profile and urinary albumin excretion. In tubular cells, paricalcitol may modulate ACE2 by blocking its shedding. In the early stage of diabetic nephropathy, paricalcitol treatment counterbalances the effect of diabetes on circulating ACE2 activity. Our results suggest that additional use of paricalcitol may be beneficial in treating patients with diabetes under standard therapeutic strategies.

Effects of aqueous extract of Hibiscus sabdariffa on the renin-angiotensin-aldosterone system of Nigerians with mild to moderate essential hypertension: A comparative study with lisinopril.

OBJECTIVES: The present study investigated the effects of aqueous extract of Hibiscus sabdariffa (HS) on the three basic components of renin-angiotensin-aldosterone system: Plasma renin, serum angiotensin-converting enzyme (ACE), and plasma aldosterone (PA) in mild to moderate essential hypertensive Nigerians and compared with that of lisinopril, an ACE inhibitor. MATERIALS AND METHODS: A double-blind controlled randomized clinical study was used. Seventy-eight newly diagnosed but untreated mild to moderate hypertensive subjects attending Medical Outpatients Clinic of Enugu State University Teaching Hospital, Enugu were recruited for the study. Those in Group A received placebo (150 mg/kg/day), Group B were given lisinopril (10 mg once daily) while those in Group C received aqueous extract of HS (150 mg/kg/day). After 4 weeks of treatment, the levels of plasma renin, serum ACE, and PA were determined. RESULTS: HS and lisinopril significantly (P < 0.001) reduced PA compared to placebo by 32.06% and 30.01%, respectively. Their effects on serum ACE and plasma renin activity (PRA) were not significant compared to placebo; they reduced ACE by 6.63% and 5.67% but increased plasma PRA by 2.77% and 5.36%, respectively. CONCLUSION: HS reduced serum ACE and PA in mild to moderate hypertensive Nigerians with equal efficacy as lisinopril. These actions are possibly due to the presence of anthocyanins in the extract.

Inhibition of angiotensin-converting enzyme by aqueous extract of tomato.

PURPOSE: To investigate the presence of anti-angiotensin converting enzyme (ACE) factors in aqueous extract of tomato. METHODS: The bio-guided fractionation of the aqueous extract of tomato produced a sugar-free, heat-stable fraction with molecular mass <1,000 Da from tomatoes. The sugar-free tomato extract (TE) was tested for its anti-ACE activity using human plasma and rabbit lung pure ACE. In addition, its effect on human platelet aggregation induced by ADP, collagen or arachidonic acid was determined. The mechanism of platelet inhibitory action of TE was investigated by measuring platelet factor 4 (PF4) release and cAMP synthesis by platelets. RESULTS: Typically, 100 g tomatoes produced 72.2 ± 4.7 mg of TE. This extract inhibited both platelet aggregation and plasma ACE activity in a dose-dependent manner. It inhibited platelet aggregation in response to ADP, collagen or arachidonic acid, and inhibitory action was mediated in part by reducing platelet PF4 release and by stimulating cAMP synthesis. The IC50 value of TE for ADP-induced platelet aggregation was 0.4 ± 0.02 mg/ml, whereas the IC50 value for ACE enzyme inhibition was 1.40 ± 0.04 mg/ml. Both the TE and commercially available sugar-free TE, Fruitflow(®)-2 had similar amount of catechin, and also had equal inhibitory potencies against platelet aggregation and plasma ACE activity. CONCLUSION: Together these data indicate that aqueous extract of tomatoes contain anti-ACE factors in addition to previously described anti-platelet factors.

Effect of buttermilk consumption on blood pressure in moderately hypercholesterolemic men and women.

OBJECTIVES: Milk fat globule membrane (MFGM) found in buttermilk is rich in unique bioactive proteins. Several studies suggest that MFGM proteins possess biological activities such as cholesterol-lowering, antiviral, antibacterial, and anticancer properties, but data in humans are lacking. Furthermore, to our knowledge, no study has yet investigated the antihypertensive potential of MFGM proteins from buttermilk. The aim of this study was to investigate the effects of buttermilk consumption on blood pressure and on markers of the renin-angiotensin-aldosterone (RAS) system in humans. METHODS: Men and women (N = 34) with plasma low-density lipoprotein cholesterol < 5 mmol/L and normal blood pressure (< 140 mm Hg) were recruited in this randomized, double-blind, placebo-controlled, crossover study. Their diets were supplemented with 45 g/d of buttermilk and with 45 g/d of a macro-/micronutrient-matched placebo in random order (4 wk for each diet). RESULTS: Buttermilk consumption significantly reduced systolic blood pressure (-2.6 mm Hg; P = 0.009), mean arterial blood pressure (-1.7 mm Hg; P = 0.015), and plasma levels of the angiotensin I-converting enzyme (-10.9%; P = 0.003) compared with the placebo, but had no effect on plasma concentrations of angiotensin II and aldosterone. CONCLUSION: Short-term buttermilk consumption reduces blood pressure in normotensive individuals.