Potassium Homeostasis, Oxidative Stress, and Human Disease

Update on management of hypokalemia and goals for the lower potassium level in patients with cardiovascular disease: A review in collaboration with the European Society of Cardiology Working Group on Cardiovascular Pharmacotherapy

Hypokalaemia is common in patients with cardiovascular disease. In this review, we emphasize the importance of tight potassium regulation in patients with cardiovascular disease based on findings from observational studies. To enhance the understanding, we also describe the mechanisms of potassium homeostasis maintenance, the most common causes of hypokalaemia and present strategies for monitoring and management of low potassium levels. We propose elevation of potassium in asymptomatic patients with lower normal concentrations and concurrent cardiovascular disease. These proposals are intended to assist clinicians until more evidence is available.

Molecular Basis of the Therapeutical Potential of Clove (Syzygium aromaticum L.) and Clues to Its Anti-COVID-19 Utility

The current COronaVIrus Disease 19 (COVID-19) pandemic caused by SARS-CoV-2 infection is enormously affecting the worldwide health and economy. In the wait for an effective global immunization, the development of a specific therapeutic protocol to treat COVID-19 patients is clearly necessary as a short-term solution of the problem. Drug repurposing and herbal medicine represent two of the most explored strategies for an anti-COVID-19 drug discovery. Clove (Syzygium aromaticum L.) is a well-known culinary spice that has been used for centuries in folk medicine in many disorders. Interestingly, traditional medicines have used clove since ancient times to treat respiratory ailments, whilst clove ingredients show antiviral and anti-inflammatory properties. Other interesting features are the clove antithrombotic, immunostimulatory, and antibacterial effects. Thus, in this review, we discuss the potential role of clove in the frame of anti-COVID-19 therapy, focusing on the antiviral, anti-inflammatory, and antithrombotic effects of clove and its molecular constituents described in the scientific literature.

Impact of Plasma Potassium Normalization on Short-Term Mortality in Patients With Hypertension and Hyperkalemia

Background Hyperkalemia can be harmful, but the effect of correcting hyperkalemia is sparsely studied. We used nationwide data to examine hyperkalemia follow-up in patients with hypertension. Methods and Results We identified 7620 patients with hypertension, who had the first plasma potassium measurement ≥4.7 mmol/L (hyperkalemia) within 100 days of combination antihypertensive therapy initiation. A second potassium was measured 6 to 100 days after the episode of hyperkalemia. All-cause mortality within 90 days of the second potassium measurement was assessed using Cox regression. Mortality was examined for 8 predefined potassium intervals derived from the second measurement: 2.2 to 2.9 mmol/L (n=37), 3.0 to 3.4 mmol/L (n=184), 3.5 to 3.7 mmol/L (n=325), 3.8 to 4.0 mmol/L (n=791), 4.1 to 4.6 mmol/L (n=3533, reference), 4.7 to 5.0 mmol/L (n=1786), 5.1 to 5.5 mmol/L (n=720), and 5.6 to 7.8 mmol/L (n=244). Ninety-day mortality in the 8 strata was 37.8%, 21.2%, 14.5%, 9.6%, 6.3%, 6.2%, 10.0%, and 16.4%, respectively. The multivariable analysis showed that patients with concentrations >5.5 mmol/L after an episode of hyperkalemia had increased mortality risk compared with the reference (hazard ratio [HR], 2.27; 95% CI, 1.60-3.20; P<0.001). Potassium intervals 3.5 to 3.7 mmol/L and 3.8 to 4.0 mmol/L were also associated with increased risk of death (HR, 1.71; 95% CI, 1.23-2.37; P<0.001; HR, 1.36; 95% CI, 1.04-1.76; P<0.001, respectively) compared with the reference group. We observed a trend toward increased risk of death within the interval 5.1 to 5.5 mmol/L (HR, 1.29; 95% CI, 0.98-1.69). Potassium concentrations <4.1 mmol/L and >5.0 mmol/L were associated with increased risk of cardiovascular death. Conclusions Overcorrection of hyperkalemia to levels <4.1 mmol/L was frequent and associated with increased all-cause and cardiovascular mortality. Potassium concentrations >5.5 mmol/L were also associated with an increased all-cause and cardiovascular mortality.

Viburnum opulus L.-A Review of Phytochemistry and Biological Effects

Viburnum opulus (VO) is a valuable decorative, medicinal, and food plant. This deciduous shrub is found in natural habitats in Europe, Russia, and some regions in North Africa and North Asia. The VO is traditionally used to treat aliments such as cough, colds, tuberculosis, rheumatic aches, ulcers, stomach, and kidney problems, among others. Many of the health-promoting properties of VO are associated with antioxidant activity, which has been demonstrated in both in vitro and in vivo studies. The results of in vitro studies show the antimicrobial potential of VO, especially against Gram-positive bacteria. In cell-based studies, VO demonstrated anti-inflammatory, anti-obesity, anti-diabetic, osteogenic, cardio-protective, and cytoprotective properties. The applicability of VO in the treatment of urinary tract diseases, endometriosis, and some cancers has been confirmed in in vivo studies. The health benefits of VO result from the presence of bioactive components such as phenolic compounds, vitamin C, carotenoids, iridoids, and essential oils. The aim of this review is to present an overview of the botanical characteristics, chemical compositions, including bioactive compounds, and pro-health properties of VO different morphological parts.

Unexplored nutritive potential of tomato to combat global malnutrition

Tomato, a widely consumed vegetable crop, offers a real potential to combat human nutritional deficiencies. Tomatoes are rich in micronutrients and other bioactive compounds (including vitamins, carotenoids, and minerals) that are known to be essential or beneficial for human health. This review highlights the current state of the art in the molecular understanding of the nutritional aspects, conventional and molecular breeding efforts, and biofortification studies undertaken to improve the nutritional content and quality of tomato. Transcriptomics and metabolomics studies, which offer a deeper understanding of the molecular regulation of the tomato's nutrients, are discussed. The potential uses of the wastes from the tomato processing industry (i.e., the peels and seed extracts) that are particularly rich in oils and proteins are also discussed. Recent advancements with CRISPR/Cas mediated gene-editing technology provide enormous opportunities to enhance the nutritional content of agricultural produces, including tomatoes. In this regard, genome editing efforts with respect to biofortification in the tomato plant are also discussed. The recent technological advancements and knowledge gaps described herein aim to help explore the unexplored nutritional potential of the tomato.

Statistical Assessment of Toxic and Essential Metals in the Serum of Female Patients with Lung Carcinoma from Pakistan

Lung cancer (LC) is the number one cancer killer of women both in the USA and around the world. Besides cigarette smoking, an important feature in the etiology of LC is its strong association with exposure of toxic metals. The primary objective of the present investigation was to assess the concentrations of toxic/essential elements (Ni, Ca, Se, Zn, Co, K, Cr, As, Cu, Na, Fe, Hg, Cd, Mg, Mn, and Pb) in the serum samples of LC female patients with female controls by atomic absorption spectrometry after wet-acid digestion procedure. Carcinoembryonic antigen (CEA) was also measured in the serum of the patients using immunoradiometric method. Comparative appraisal of the data revealed that concentrations of Cr, Mg, Cd, Pb, Hg, As, and Ni were noted to be high significantly in serum of LC female patients, while the average Fe, Co, Mn, Na, K, Zn, Ca, and Se were observed at higher levels in female controls (p < 0.05). The correlation study revealed significantly different mutual associations among the elements in the both donor groups. Markedly, variations in the elemental levels were also noted for different types (non-small cell lung cancer and small cell lung cancer) and stages (I, II, III, & IV) of LC patients. Multivariate analyses showed substantially diverse apportionment of the metals in the female patients and female controls. Hence, present findings suggest that the toxic and essential metals accumulated in the body may pose a high risk for LC progression in Pakistani females.

Hypokalemia and the Prevalence of Primary Aldosteronism

Hypokalemia is closely linked with the pathophysiology of primary aldosteronism (PA). Although hypokalemic PA is less common than the normokalemic course of the disease, hypokalemia is of particular importance for the manifestation and development of comorbidities. Specifically, a growing body of evidence demonstrates that hypokalemia in PA patients is associated with a more severe disease course regarding cardiovascular and metabolic morbidity and mortality. It is also well appreciated that low potassium levels per se can promote or exacerbate hypertension. The spectrum of hypokalemia-related symptoms ranges from asymptomatic courses to life-threatening conditions. Hypokalemia is found in 9-37% of all cases of PA with a predominance in patients with aldosterone producing adenoma. Conversely, hypokalemia resolves in almost 100% of cases after both, specific medical or surgical treatment of the disease. However, to date, high-level evidence about the prevalence of primary aldosteronism in a hypokalemic population is missing. Epidemiological data are expected from the recently launched IPAHK+study ("Incidence of Primary Aldosteronism in Patients with Hypokalemia").

Food Sources of Potassium in the Average Polish Diet

The aim of this study was to identify the food sources of potassium in the average Polish diet based on the data from the 2016 Household Budget Survey conducted on the representative sample of the Polish population (36,886 households, n = 99,230). This survey is organized by the Central Statistical Office and is related to the expenditures, quantitative consumption and revenues in households. We analyzed 91 sub-groups (i.e., milk, red meat) from 13 food categories (i.e., milk and dairy products, meat and products). Our findings indicated that the daily supply of potassium in the average Polish diet was 2617.9 mg, which meant covering the average allowance in 83%. Vegetables provided 32.5% of potassium, of which potatoes accounted for 16.2% of supply, and other vegetables for 16.2%. Tomatoes as well as other vegetables and mushrooms provided a total of 8.2% of potassium among vegetables. The next position was taken by the meat and meat products category (17.7%), with the largest share of meat products (6.7%) and red meat (5.2%). Cereal products supplied 16.64% of potassium, of which bread, rolls and bread products (12.2%) were of the greatest importance. Milk and dairy products turned out to be the fourth product category as a source of potassium (11.9%), with the highest share of milk (6.8%) and yoghurts and milk drinks (3.9%).

Muscle transcriptome analysis reveals genes and metabolic pathways related to mineral concentration in Bos indicus

Mineral content affects the biological processes underlying beef quality. Muscle mineral concentration depends not only on intake-outtake balance and muscle type, but also on age, environment, breed, and genetic factors. To unveil the genetic factors involved in muscle mineral concentration, we applied a pairwise differential gene expression analysis in groups of Nelore steers genetically divergent for nine different mineral concentrations. Here, based on significant expression differences between contrasting groups, we presented candidate genes for the genetic regulation of mineral concentration in muscle. Functional enrichment and protein-protein interaction network analyses were carried out to search for gene regulatory processes concerning each mineral. The core genetic regulation for all minerals studied, except Zn, seems to rest on interactions between components of the extracellular matrix. Regulation of adipogenesis-related pathways was also significant in our results. Antagonistic patterns of gene expression for fatty acid metabolism-related genes may explain the Cu and Zn antagonistic effect on fatty acid accumulation. Our results shed light on the role of these minerals on cell function.

Molecular Mechanism for Selective Cytotoxicity towards Cancer Cells of Diselenide-Containing Paclitaxel Nanoparticles

Diselenide-containing paclitaxel nanoparticles (SePTX NPs) indicated selectivity of cytotoxicity between cancerous and normal cells in our previous work. Herein, the mechanism is revealed by molecular biology in detail. Cancer cells and normal cells were treated with the SePTX NPs and cell proliferation was measured using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay and cell morphology. Measurement of reactive oxygen species (ROS) levels and biochemical parameters were employed to monitor oxidative stress of the cells. JC-1 assay was used to detect the mitochondrial dysfunction of the cells. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) analysis was used to detect apoptosis of the cells. Immunofluorescence analysis and western blotting were employed to monitor changes in signaling pathway-related proteins. Compared with PTX, SePTX NPs has a good selectivity to cancer cells and can obviously induce the proliferation damage of cancer cells, but has no significant toxicity to normal cells, indicating that SePTX NPs has a specific killing effect on cancer cells. The results of mechanism research show that SePTX NPs can successfully inhibit the depolymerization of microtubules and induce cell cycle arrest, which is related to the upregulation of p53 and CyclinB1. Simultaneously, SePTX NPs can successfully induce oxidative stress, cause mitochondrial dysfunction, resulting in mitochondrial pathway-mediated apoptosis, which is related to the upregulation of autophagy-related protein LC3-II. On the other hand, lewis lung cancer C57BL/6 mice were used to evaluate the anti-tumor effects of SePTX NPs in vivo. Our data show that SePTX NPs exhibited high inhibiting efficiency against the growth of tumors and were able to reduce the side effects. Collectively, these data indicate that the high antitumor effect and selective cytotoxicities of SePTX NPs is promising in future cancer therapy.

Arsenic exposure intensifies glycogen nephrosis in diabetic rats

It is known that either arsenic exposure or diabetes can impact renal function. However, it is unclear how these combined factors may influence kidney functions. Therefore, we evaluated morphological, functional, and oxidative parameters in the kidney of diabetic rats exposed to arsenic. Healthy male Wistar rats and streptozotocin-induced diabetic rats were exposed to 0 and 10 mg/L arsenate through drinking water for 40 days. Renal tissue was assessed using morphometry, mitosis and apoptosis markers, mineral proportion, oxidative stress markers, as well as the activity of antioxidant enzymes and membrane-bound adenosine triphosphatases. Arsenate intake altered glucose levels in healthy animals, but it did not reach hyperglycemic conditions. In diabetic animals, arsenate led to a remarkable increase of glycogen nephrosis in distal tubules. In these animals, additionally, the activity of catalase and glutathione S-transferase, besides the proportion of Fe, Cu, and K in renal tissue, was altered. Nevertheless, arsenate did not accumulate in the kidney and did not impact on other parameters previously altered by diabetes, including levels of malondialdehyde, Na, urea, creatinine, and apoptosis and mitosis markers. In conclusion, besides the intensification of glycogen nephrosis, the kidney was able to handle arsenate toxicity at this point, preventing arsenic deposition in the exposed groups and the impairment of renal function.

Characteristics, Risk Factors, and Adverse Outcomes of Hyperkalemia in Acute-on-Chronic Liver Failure Patients

Background

Hyperkalemia is a serious complication in cirrhotic patients. However, the clinical characteristics, risk factors, and its impact on the outcomes in acute-on-chronic liver failure (ACLF) patients remain unclear.

Methods

We retrospectively recruited 650 ACLF patients in this study. The risk factors associated with hyperkalemia and its relationship with 90-day mortality were analyzed using multivariable regression models.

Results

Among 650 patients with ACLF, 12.2% (79/650) had hyperkalemia during hospitalization. Higher admission serum potassium levels and the presence of acute kidney injury (AKI) were independent risk factors for hyperkalemia. The prevalence rates of hyperkalemia in patients with and without AKI were 23.6% and 4.6%, respectively (P<0.001). Hyperkalemia was a predictor of mortality in AKI and non-AKI patients. The 90-day mortality rates in non-AKI patients with and without hyperkalemia were 44.4% and 24.7%, respectively (P<0.001), and in AKI patients with and without hyperkalemia were 80.3% and 56.6%, respectively (P<0.001). Hepatic encephalopathy (HE), gastrointestinal bleeding, AKI, hyperkalemia, elevated total bilirubin (TBIL) and international normalized ratio (INR) values, and higher Model for End-Stage Liver Disease (MELD) and chronic liver failure-sequential organ failure assessment (CLIF-SOFA) scores were independent risk factors for predicting the 90-day mortality in ACLF patients.

Conclusions

Hyperkalemia increases the 90-day mortality in ACLF patients; hyperkalemia is associated with AKI. Patients with both AKI and hyperkalemia had the worst outcome.

Construction of K+ responsive surface on SEBS to reduce the hemolysis of preserved erythrocytes

Hemolysis of stored erythrocytes is a big obstacle for the development of new plasticizer-free polymer containers. Hemolysis is mainly caused by cell membrane oxidation and cation leaks from the intracellular fluid during storage. To construct an anti-hemolytic surface for a plasticizer-free polymer, we fabricated 2-O-α-d-glucopyranosyl-l-ascorbic acid (AA-2G)-loaded polycaprolactone (PCL)-crown ether micro/nanofibers on the surface of styrene-b-(ethylene-co-butylene)-b-styrene (SEBS). Our strategy is based on the sensitive response of the crown ether to leaked potassium, causing the release of AA-2G, the AA-2G can then remove the excess ROS, maintaining the Na/K-pump activity and the cell integrity. We demonstrated that the PCL-crown ether micro/nanofibers have been well prepared on the surface of SEBS; the micro/nanofibers provide a sensitive response to excess K⁺ and trigger the rapid release of AA-2G. AA-2G then acts as an antioxidant to reduce the excess ROS and maintain the Na/K-pump activity to mitigate cation leaks, resulting in the reduced hemolysis of the preserved erythrocytes. Our work thus provides a novel method for the development of plasticizer-free polymers for the storage of erythrocytes, and has the potential to be used to fabricate long-term anti-hemolytic biomaterials for in vivo use.

A K⁺ responsive surface was constructed on a SEBS substrate to release anti-oxidants to reduce hemolysis of the preserved red blood cells.

Hypokalemia: a clinical update

Hypokalemia is a common electrolyte disturbance, especially in hospitalized patients. It can have various causes, including endocrine ones. Sometimes, hypokalemia requires urgent medical attention. The aim of this review is to present updated information regarding: (1) the definition and prevalence of hypokalemia, (2) the physiology of potassium homeostasis, (3) the various causes leading to hypokalemia, (4) the diagnostic steps for the assessment of hypokalemia and (5) the appropriate treatment of hypokalemia depending on the cause. Practical algorithms for the optimal diagnostic, treatment and follow-up strategy are presented, while an individualized approach is emphasized.