Oxidant-induced disruption of vascular K+ channel function: implications for diabetic vasculopathy

Diabetes in humans a chronic metabolic disorder characterised by hyperglycaemia, it is associated with an increased risk of cardiovascular disease, disruptions to metabolism and vascular functions. It is also linked to oxidative stress and its complications. Its role in vascular dysfunctions is generally reported without detailed impact on the molecular mechanisms. Potassium ion channel (K+ channels) are key regulators of vascular tone, and as membrane proteins, are modifiable by oxidant stress associated with diabetes. This review manuscript examined the impact of oxidant stress on vascular K+ channel functions in diabetes, its implication in vascular complications and metabolic and cardiovascular diseases.

Identification of phytochemicals and assessment of hypoglycemic and haematological potentials of Terminalia catappa Linn leaf extract in alloxan-induced diabetic Wistar rats

INTRODUCTION

Hypoglycemia and anemia are associated with diabetes mellitus. Medicinal plants and orthodox drugs have been used for the management of this disease. This study aimed to validate the ethnomedical claims of Terminalia catappa Linn. leaf extract in reducing hyperglycemia and hematological potentials in alloxan-induced diabetic rats and to identify likely antidiabetic compounds.

MATERIALS AND METHODS

Ultra-high-performance liquid chromatography was used to identify the various phytochemical constituents. Male Wistar rats were randomly divided into five groups containing 6 rats per group. Group 1 (control) received 0.2 ml/kg of distilled water, group 2 received 130 mg/kg of T. catappa aqueous extract, groups 3-5 were diabetic and received 0.2 ml/g distilled water, 130 mg/kg T. catappa extract and 0.75 IU/kg insulin respectively for 14 days. Hematological parameters were measured and an oral glucose tolerance test was carried out using 2 g/kg body weight glucose. A histological analysis of the pancreas was done.

RESULTS

Twenty-five compounds identified as flavonoids, phenolic acids, tannins, and triterpenoids were detected. The blood glucose levels were significantly (p<0.05) elevated in DM groups but were significantly (p<0.05) reduced following Terminalia catappa leaves extract to DM groups. There was s significant (p<0.05) increase in insulin levels improved hematological parameters (RBC, WBC, and platelets), and increased islet population.

CONCLUSION

These results suggest that T. catappa extract has hypoglycemic, insulinogenic, and hematopoietic potentials in diabetic condition and offer protection to the pancreas which could be attributed to the phytochemical constituents thereby justifying its use in traditional therapy.

SARS-CoV-2 Receptor-Binding Domain IgG Response to AstraZeneca AZD1222 COVID-19 Vaccination, Jamaica

The Caribbean region is lacking an assessment of the antibody response and side effects experienced after AstraZeneca COVID-19 vaccination (AZD1222). We examined severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (RBD) IgG levels and report the side effects noted in a Jamaican population after AZD1222 vaccination. Median RBD IgG levels for persons without evidence of previous SARS-CoV-2 infection were 43.1 binding international units (bIU)/mL 3 to 7 weeks after the first dose, increasing to 100.1 bIU/mL 3 to 7 weeks after the second dose, and decreasing to 46.9 bIU/mL 16 to 22 weeks after the second dose. The median RBD IgG level 2 to 8 weeks after symptom onset for unvaccinated SARS-CoV-2-infected persons of all disease severities was 411.6 bIU/mL. Common AZD1222 side effects after the first dose were injection site pain, headache, and chills. Most people reported no side effects after the second dose. AZD1222 is widely used across the English-speaking Caribbean, and our study provides evidence for its continued safe and effective use in vaccination programs.

Artocarpus altilis (breadfruit) could reverse myocardial infarction through the normalization of the Oxygen haemoglobin dissociation curve

Objective; The study was performed to assess if hematological mechanisms such as blood flow modulation, P50 and Oxygen haemoglobin dissociation are involved in Artocarpus altilis leaf extract amelioration of Isoproterenol-Induced Myocardial Damage in rats. Method; Twenty (20) adult male Sprague-Dawley rats were randomly divided into 5 groups. Group 1 served as the control, group 3 and 5 received 50 and 100 mg/kg Artocarpus altilis water extract respectively, after induced with Isoproterenol twice (85 mg/ kg) at a 24-hour period. Group 2 received 85 mg/kg isoproterenol only, while group 4 received 50 mg/kg Artocarpus altilis extract only for 6 days. The Hematological parameters were assessed using an automatic Coulter Counter, blood flow was assessed with the CODA machine using the tail cuff method, while blood viscosity measured at native hematocrit and the oxygen haemoglobin dissociation curves were assessed with the BioProfiler and Hemox Analyzer at the end of seven days. <. Results; Artocarpus altilis treatment ameliorated the ISO induced increases in viscosity, increased the ISO induced decreases blood flow and influenced oxygen release through its effects on the P50 of the oxygen hemoglobin dissociation curve, AA treatment also reversed the ISO induced weight loss. Apart from the changes in MCH, MCV, there were no significant differences in hematological parameters. Conclusion; This study reported the effects of Artocarpus atilis on the improvement of oxygen availability, the reduction of blood viscosity, and the improvement of blood flow through its influence on endothelial functions, and NO availability. Our study futher highlights The usefulness of A.atilis, as having a beneficial cardiovascular and haematological outcome in experimental myocardial infarction, and as such, a potential drug discovery for diseases of cardiovascular & hematological involvement.

May Measurement Month 2019: an analysis of blood pressure screening results from Jamaica

There is evidence of an elevated risk of hypertension in populations that are primarily of African origin. Hypertension is predominantly asymptomatic, necessitating increased awareness. May Measurement Month was a descriptive, population-based, cross-sectional study of blood pressure (BP) screening and awareness campaign conducted in 2019 in a sample of 2550 participants (≥18 years) in Jamaica. In total, 1791 (70.2%) of the participants were female, 756 (29.6%) were male, with an average age of 49.3 years, and a body mass index (kg/m²) of 28.5 (6.2). Of all participants, 2289 (89.8%) were black and 154 (6.0%) were of mixed races. Twenty-two (0.9%) had never had their BP measured, whereas 354 (13.9%) had their measurements more than a year ago, and 2129 (83.5%) had measured within the year. Of all 2550 participants, 1055 (41.4%) had hypertension, 69.9% of our subjects with hypertension were aware, whereas only 62.5% were on antihypertensive medication and 27.8% had controlled BP (systolic <140 mmHg and diastolic BP <90 mmHg). Of 660 participants on antihypertensive medication, 44.4% had controlled BP. Two hundred and seventy-six (15.4%) of women reported hypertension in a previous pregnancy. Hypertension with previous pregnancy was positively correlated with current elevation. These results suggest a high rate of raised BP among community dwellers whose hypertension had not been previously diagnosed by a health professional and warrant proactive approaches that promote community-based awareness, and regular measurements.

Hypotensive and antihypertensive effects of an aqueous extract from Guinep fruit (Melicoccus bijugatus Jacq) in rats

Melicoccus bijugatus Jacq (Mb) has been reported to have cardiovascular modulatory effects. In this study, we evaluated the antihypertensive effects and mechanism of action of Mb on N^G-Nitro-l-arginine Methyl Ester (l-NAME) and Deoxycorticosterone Acetate (DOCA) rat models. Aqueous extract of Mb fruit (100 mg/kg) was administered for 6 weeks to rats by gavage and blood pressure was recorded. Effects of the extract on vascular reactivity was evaluated using isolated organ baths, and tissues were collected for biochemical and histological analysis. The systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were significantly (P < 0.05) reduced with extract (100 mg/kg) administration and treatment compared to the hypertensive models. Mb (100 µg/mL) reduced the vascular contractility induced by phenylephrine (PE), and caused a dose-dependent relaxation of PE-induced contraction of aortic vascular rings. The vasorelaxation properties seemed to be endothelium dependent, as well as nitric oxide (NO) and guanylyl cyclase, but not prostaglandin dependent. Histomicrograph of transverse sections of the ventricles from the Mb group did not show abnormalities. The extract significantly (P < 0.05) reduced an l-NAME induced elevation of cardiac output and Creatine Kinase Muscle-Brain (CKMB), but had no significant impact on the activities of arylamine N-acetyltransferase. In conclusion, Mb significantly decreased blood pressure in hypertensive models. The extract possesses the ability to induce endothelium dependent vasodilation, which is dependent on guanylyl cyclase but not prostaglandins.

Blood Pressure Screening Campaign in Jamaica: May Measurement Month 2017

BACKGROUND

Hypertension (HTN) is responsible for a significant disease burden in Jamaica. We are reporting the results of the 2017 blood pressure (BP) screening campaign May Measurement Month in Jamaica that aimed to increase the awareness of HTN.

METHODS

Adults, 18 years old and older, from different parishes of Jamaica were invited to participate during May to June 2017. Demographic data were collected. BP, weight, and height were measured and recorded.

RESULTS

Five hundred sixty-six participants (n = 566) were enrolled, 91.6% (519) from urban areas, and 72.6% (410) were females. The average age was 53.7 (18-95) years old and body mass index was 28.2 ± 6.6 kg/m2. The prevalence of HTN was 47.3% (267/566), without gender or living areas differences (both P > 0.1). Prevalence of HTN was lower in those who self-identified as Interracial ethnicity, in comparison with Afro-Caribbean (33% vs. 48.3%; P = 0.04). About third of the hypertensive patients were not aware of the high BP (89/267; 35.6%). Between hypertensive patients, 64.4% (172/267) were receiving antihypertensive drugs. The rate of BP control was 32% of the hypertensive patients and 50% of those receiving antihypertensive medication. Significant lower BP control was observed between diabetic vs. nondiabetic patients (34.3% vs. 60%; P < 0.001).

CONCLUSION

We found a high prevalence of HTN in this population, especially in patients with diabetes or previous cardiovascular diseases. We report an increase in HTN awareness in Jamaica but more advances need to be performed to increase HTN treatment and control.

Blood pressure-reducing activity of Gongronema latifolium Benth. (Apocynaeceae) and the identification of its main phytochemicals by UHPLC Q-Orbitrap mass spectrometry

Background Gongronema latifolium Benth. (family Apocynaceae) leaves (GL) has interesting medicinal properties. The effects of extracts from G. latifolium on blood pressure (BP) and the possible mechanisms of action were also investigated. Methods The ultrahigh resolution liquid chromatography orbitrap MS analysis was used to identify the phytochemicals present. Normotensive Wistar rats were anesthetized with sodium pentobarbitone (40 mg/kg) intraperitoneally, and the jugular vein was cannulated for infusion of drugs while the carotid artery was cannulated for direct BP measurement. GL extract (5-20 mg) alone or with nifedipine (10 mg/kg), atropine (2 mg/kg), L-NAME (5 mg/kg), methyl blue (3 mg/kg) and propranolol (1 mg/kg) were administered intravenously to Wistar rats and direct BP measurements were carried out. Results Systolic and diastolic BP levels (128/90 mm Hg; MAP 103 ± 3 mm Hg) and heart rates were all significantly (p < 0.01) decreased after GL administration. Raised mean arterial pressure (MAP) and heart rate by atropine, L-NAME and methyl blue were significantly (p < 0.01) reduced after GL administration, while propranolol significantly (p < 0.01) inhibited hypotension caused by GL. Infusion of GL reduced MAP (95 ± 3 mm Hg) comparable with nifedipine (93 ± 2 mm Hg), a calcium channel blocker. The phytochemicals identified were 34 compounds, including oleanolic acid derivatives, flavonoids, antioxidant fatty acids, 2 coumarins and 2 iridoids. Conclusions These results suggest that G. latifolium has hypotensive properties mediated by the synergistic activity of the compounds, probably via the β-adrenergic blockade mechanism.

Modulatory Effect of Guinep (Melicoccus bijugatus Jacq) Fruit Pulp Extract on Isoproterenol-Induced Myocardial Damage in Rats. Identification of Major Metabolites Using High Resolution UHPLC Q-Orbitrap Mass Spectrometry

Guinep is traditionally used in the management of cardiovascular ailments. This study aims to evaluate its medicinal constituents and effects in the management of myocardial injury in an experimental isoproterenol (ISO) rat model. Sprague-Dawley rats were randomly assigned to four groups: Group 1 was the control group; Group 2 received M. bijugatus extract (100 mg/Kg; MB) for six weeks; Group 3 was given ISO (85 mg/Kg) i.p. twice during a 24-hour period; and Group 4 was given ISO (85 mg/Kg) i.p. and MB extract (100 mg/Kg) for six weeks. The MB was administered orally by gavage, daily. The blood pressure of conscious animals was measured, while ECG was performed under anesthesia. Blood and serum were collected for biochemical and hematological analysis. The ISO group treated with MB showed a significant decrease (p < 0.001) in (SBP), diastolic (DBP), mean arterial (MAP) and heart rate (HR) compared to the ISO only group. Conversely, MB treated rats that were not induced with ISO displayed a significant decreases (p < 0.001) in SBP, DBP, MAP, and HR. ISO significantly elevated the ST segment (p < 0.001) and shortened the QTc interval (p < 0.05), which were recovered after treatment with 100 mg/Kg of MB. In addition, the results showed a significant decrease (p < 0.001) in the heart to body weight ratio of the ISO group treated with MB compared to the ISO only group. Furthermore, the extract normalized the hematological values depressed by the ISO while significantly elevating the platelet count. UHPLC high-resolution orbitrap mass spectrometry analysis results revealed the presence of several antioxidants like vitamin C and related compounds, phenolic acids, flavonoid, fatty acids (oxylipins), and terpene derivatives. The results of this study indicated that Melicoccus bijugatus did display some cardio-protective effects in relation to myocardial injury.

Genomic coordinates and continental distribution of 120 blood group variants reported by the 1000 Genomes Project

BACKGROUND

The 1000 Genomes Project provides a database of genomic variants from whole genome sequencing of 2504 individuals across five continental superpopulations. This database can enrich our background knowledge of worldwide blood group variant geographic distribution and identify novel variants of potential clinical significance.

STUDY DESIGN AND METHODS

The 1000 Genomes database was analyzed to 1) expand knowledge about continental distributions of known blood group variants, 2) identify novel variants with antigenic potential and their geographic association, and 3) establish a baseline scaffold of chromosomal coordinates to translate next-generation sequencing output files into a predicted red blood cell (RBC) phenotype.

RESULTS

Forty-two genes were investigated. A total of 604 known variants were mapped to the GRCh37 assembly; 120 of these were reported by 1000 Genomes in at least one superpopulation. All queried variants, including the ACKR1 promoter silencing mutation, are located within exon pull-down boundaries. The analysis yielded 41 novel population distributions for 34 known variants, as well as 12 novel blood group variants that warrant further validation and study. Four prediction algorithms collectively flagged 79 of 109 (72%) known antigenic or enzymatically detrimental blood group variants, while 4 of 12 variants that do not result in an altered RBC phenotype were flagged as deleterious.

CONCLUSION

Next-generation sequencing has known potential for high-throughput and extended RBC phenotype prediction; a database of GRCh37 and GRCh38 chromosomal coordinates for 120 worldwide blood group variants is provided as a basis for this clinical application.

Aqueous extract from leaf of Artocarpus altilis provides cardio-protection from isoproterenol induced myocardial damage in rats: Negative chronotropic and inotropic effects

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Artocarpus altilis (Parkinson ex F.A.Zorn, Fosberg) (Moraceae) are used in the management of hypertension; this study assessed the cardio-protective effects of the leaf extract on isoproterenol (ISO) induced myocardial damage in rats.

MATERIAL AND METHODS

Twenty (20) adult male Sprague-Dawley rats (175-230g) were divided into 5 groups. Group 1 (Control), 2 (AA) received 50mg/Kg Artocarpus altilis (AA) only; 3 (ISO) received 85mg/Kg ISO only; 4 (ISO+AA/50) and 5 (ISO+AA/100) received 50 and 100mg/Kg AA respectively for 6 days, after induced with ISO twice (85mg/Kg) at a 24-h period. Blood pressure readings were taken before and after the administering of ISO using the tail cuff method. ECG was performed on anaesthetized rats. Cardiac contractility was measured in isolated right atrial muscles. Assessment of myocardial infarct (MI) size, heart/body weight ratio, biochemical, hematological and histo-morphological parameters were conducted at the end of seven days. An aqueous extract from leaves of A. altilis was analyzed for organic compounds using UHPLC mass spectrometry.

RESULTS

ISO induced myocardial damage through an elevation of the heart rate (HR), infarct size and ECG distortions. Treatment with AA significantly (p˂0.05) reduced heart/body weight ratio (49%), MI (96%), HR (27%), sympathovagal imbalance (36%) and serum cardiac biomarkers (AST, LDH, HDL, triglycerides and CCK) caused by ISO. AA decreased the beat frequency of isolated right atrium (11%) cause by ISO, an action similar to propranolol (beta-adrenergic antagonist; 20%), but showed no significant changes in the QTc intervals of the ECG (suggesting no cardio-toxic drug-herb interactions), Thirty nine compounds were detected using high resolution LC-MS analysis (HPLC-Orbitrap-APCI-MS) in the extract. Pure compounds, as gallic acid and rutin, presented a higher negative chronotropic effect, similar to propranolol.

CONCLUSION

Oral administration of aqueous extract of Artocarpus artilis has cardio-protective functions in myocardial injury, in part, by decreasing the HR, reduced contractility and infarct size. These findings may explain the cardio-protective use of A. altilis in traditional medicine.

A comparative study of the effect of some nutritional medicinal plants effect on lead accumulation in the liver following different modes of administration

Context and Objectives:

Lead (Pb) toxicity leads to cell damage in many organs of the body. Using different treatment interventions and modes of administration we comparatively examined the protective ability of some medicinal plants on liver Pb accumulation.

Materials and Methods:

Rats were fed on either 7% w/w Zingiber officinale, 7% w/w Allium sativum, 10% w/w Lycopersicon esculentum, 5%, w/w Garcinia kola (all in rat chow), while Pb (100 ppm) was given in drinking water. The additives were administered together with (mode 1), a week after exposure to (mode 2) or a week before metal exposure to (mode 3) the metal for a period of 6 weeks. The metal accumulations in the liver were determined using atomic absorption spectrometry and compared using analysis of variance.

Results:

Some additives significantly (P < 0.05) reduced, while others enhanced Pb accumulation. Mode 2 yielded the highest mean % protection and mode 3 the lowest, no significant interaction between modes of administration and time of measurement in their relationships to percentage protection, but there was statistically significant (P < 0.05) interaction between modes of administration and additive used in their relationships to percentage protection.

Conclusion:

Protective effects of medicinal plants are varied and depend on the nature of lead exposure.

Apocynin ameliorates cadmium-induced hypertension through elevation of endothelium nitric oxide synthase

Apocynin is reported to have antioxidant and NADPH oxidase inhibitor activities. Cadmium toxicity is reported to causes oxidative damage, resulting in vascular dysfunction, reduced bioavailability of nitric oxide (NO) and hypertension. The study aimed to investigate the protective effects of apocynin in cadmium-induced hypertension. Thirty-six (36) adult male Sprague-Dawley rats were randomly divided into 6 groups. Group 1 served as control, Groups 2 and 3 received 50 and 100 mg/Kg (b.w) apocynin, respectively, Group 4 received 100 ppm CdCl2 in their drinking water, while Group 5 and 6 received 100 ppm CdCl2 in their drinking and 50 and 100 mg/Kg (b.w) apocynin, respectively, for 8 weeks. Blood pressure readings were taken weekly using the tail-cuff method. cGMP, endothelial nitric oxide synthase (eNOS), NO and hematological parameters were analyzed at the end of 8 weeks. Apocynin, although a poor antioxidant, caused a significant reduction (p < 0.05) in systolic and mean arterial pressures in the cadmium-induced elevations in blood pressure and amelioration of altered hematological parameters. However, while cadmium exposures did not alter the cGMP, eNOS and nitrate concentrations in serum, apocynin reduced the cGMP and nitrite values while significantly elevating (p < 0.05) the eNOS concentrations and also improved the cadmium-induced anemia. Apocynin was effective in reducing cadmium-induced elevated blood pressures through elevation of eNOS. Inhibition of NADPH oxidase activity may be a useful strategy for prevention and treatment of cadmium-induced hypertension.

Investigation of effects of time of measurement and modes of administration on cadmium accumulation in rat liver under some medicinal plants food supplemented diet

Context and Objectives:

Cadmium (Cd) toxicity leads to cell and organ damage, we comparatively examined the protection ability of different medicinal plants on Cd liver accumulation following different treatment interventions and modes of administration.

Materials and Methods:

Rats were fed either 7% w/w Zingiber officinale, 7% w/w Allium Sativum, 10% w/w Lycopersicon esculentum, 5%, w/w Garcinia kola (all in rat chow), while Cd (200 ppm) was given in drinking water. Additives were administered together with (mode 1), a week after (mode 2) or a week before metal exposure (mode 3) for a period of six weeks. Cd liver was determined using AAS and compared using analysis of variance (ANOVA).

Results:

All additives significantly (P <0.5) reduced the accumulation of Cd in the liver. After adjusting for time and mode of administration, mean %protection for week 4 was significantly lower by 14.1% (P=0.02) from that for week 2 but the means did not differ with respect to additive used or mode of administration, no statistically significant interaction between modes of administration and either of additives used or time of administration in their respective relationships to percentage protection from Cd.

Conclusion:

Additives significantly reduced Cd accumulation through a reduction in absorption and enhancement of metal excretion.

Proteins and liver function changes in rats following cumulative total body irradiations

OBJECTIVE

Total body irradiation (TBI) is a choice therapy for the management of some malignancies; it is also a major cause of oxidative stress. The aim of this research is to sequentially document the effect of total body radiation on body function utilizing the sequential changes in liver function enzymes and proteins in rats.

METHODS

Serum protein and liver enzymes were assessed using kits in rats exposed to total body radiations of 1.27 Gy/minute in cumulative doses to the fourth radiation at five-day intervals.

RESULTS

Aspartate aminotransferase (AST), alanine transaminase (ALT) and serum protein were significantly (p < 0.05) elevated with increasing radiation. No significant differences between experimental and control groups for bilirubin concentrations were noted at any time. Serum levels of albumin were significantly (p < 0.05) increased with the first to third radiation exposures but reduced at the fourth cumulative dose exposure.

CONCLUSION

Variations are associated with acute stress, inflammation which could be due to nonspecific stress reaction, while fluctuations could arise as a result of tolerance and repair within the liver These tests are significant for diagnosis of radiation-induced injury and can be important for evaluation of its severity and correct management.