Temperature-Dependent Olive Pomace Extraction for Obtaining Bioactive Compounds Preventing the Death of Murine Cortical Neurons.

High-pressure and temperature extraction (HPTE) can effectively recover bioactive compounds from olive pomace (OP). HPTE extract obtained by extracting OP with ethanol and water (50:50 v/v) at 180 °C for 90 min demonstrated a pronounced ability to preserve intracellular calcium homeostasis, shielding neurons from the harmful effects induced by N-methyl-d-aspartate (NMDA) receptor (NMDAR) overactivation, such as aberrant calpain activation. In this study, the extraction temperature was changed from 37 to 180 °C, and the extracts were evaluated for their antioxidant potency and ability to preserve crucial intracellular Ca2+-homeostasis necessary for neuronal survival. Additionally, to verify the temperature-induced activity of the extract, further extractions on the exhausted olive pomace were conducted, aiming to identify variations in the quality and quantity of extracted phenolic molecules through HPLC analysis. The results revealed a significant increase in bioactive compounds as a function of temperature variation, reaching 6.31 ± 0.09 mgCAE/mL extract for the extraction performed at 180 °C. Subsequent extraction of the exhausted residues yielded extracts that remained active in preventing calcium-induced cell death. Moreover, despite increased antiradical power, extracts re-treated at 180 °C did not display cell protection activity. Our results indicate that the molecules able to maintain physiological Ca2+-homeostasis in murine cortical neurons in conditions of cytotoxic stimulation of NMDAR are wholly recovered from olive pomace only following extraction performed at 180 °C.

Revisiting the significance of nano-vitamin D for food fortification and therapeutic application.

OBJECTIVE: Vitamin D (a prohormone) is an important micronutrient required by the body for skeletal homeostasis and a range of non-skeletal actions. Calcitriol, the active form of vitamin D, regulates a variety of cellular and metabolic processes through both genomic and nongenomic pathways. Often prescribed for treating rickets and osteoporosis, vitamin D deficiency can exacerbate various other medical conditions. SIGNIFICANCE, METHODS, AND RESULTS: Despite its multifunctional uses, the sensitivity of vitamin D makes formulating an efficient drug delivery system a challenging task, which is further complicated by its poor aqueous solubility. Enhancing the oral absorption of vitamin D is vital in utilizing its full efficacy. Recent developments in encapsulation and nanotechnology have shown promising results in overcoming these constraints. CONCLUSION: This review thus offers an insight to adequately comprehend the mechanistic pharmacology of vitamin D, its pathophysiological role, and justification of its medical indications, along with the benefits of utilizing nanotechnology for vitamin D delivery.

Irisin attenuates vascular remodeling in hypertensive mice induced by Ang II by suppressing Ca2+-dependent endoplasmic reticulum stress in VSMCs.

Vascular remodeling plays a vital role in hypertensive diseases and is an important target for hypertension treatment. Irisin, a newly discovered myokine and adipokine, has been found to have beneficial effects on various cardiovascular diseases. However, the pharmacological effect of irisin in antagonizing hypertension-induced vascular remodeling is not well understood. In the present study, we investigated the protection and mechanisms of irisin against hypertension and vascular remodeling induced by angiotensin II (Ang II). Adult male mice of wild-type, FNDC5 (irisin-precursor) knockout, and FNDC5 overexpression were used to develop hypertension by challenging them with Ang II subcutaneously in the back using a microosmotic pump for 4 weeks. Similar to the attenuation of irisin on Ang II-induced VSMCs remodeling, endogenous FNDC5 ablation exacerbated, and exogenous FNDC5 overexpression alleviated Ang II-induced hypertension and vascular remodeling. Aortic RNA sequencing showed that irisin deficiency exacerbated intracellular calcium imbalance and increased vasoconstriction, which was parallel to the deterioration in both ER calcium dysmetabolism and ER stress. FNDC5 overexpression/exogenous irisin supplementation protected VSMCs from Ang II-induced remodeling by improving endoplasmic reticulum (ER) homeostasis. This improvement includes inhibiting Ca2+ release from the ER and promoting the re-absorption of Ca2+ into the ER, thus relieving Ca2+-dependent ER stress. Furthermore, irisin was confirmed to bind to its receptors, αV/ß5 integrins, to further activate the AMPK pathway and inhibit the p38 pathway, leading to vasoprotection in Ang II-insulted VSMCs. These results indicate that irisin protects against hypertension and vascular remodeling in Ang II-challenged mice by restoring calcium homeostasis and attenuating ER stress in VSMCs via activating AMPK and suppressing p38 signaling.

Are Twin Pregnancies at Higher Risk for Iron and Calcium Deficiency than Singleton Pregnancies?

The aim of this study was to compare the iron and calcium status in singleton and twin pregnancies and to assess whether there is an increased risk for iron and calcium deficiency in twin gestation. The study included 105 singleton and 9 twin pregnancies at or above 35 weeks of gestation. Information on prenatal supplementation with iron or calcium was acquired, and adverse perinatal outcomes were recorded. Biosamples from all 114 mothers and 73 newborns (61 singleton and 12 twin newborns) were finally analyzed. Total iron and calcium concentrations in serum were measured through total reflection X-ray fluorescence analysis. The results indicated no significant differences in maternal serum iron and calcium concentrations between singleton and twin pregnancies. Similarly, iron and calcium concentrations in newborn umbilical cord serum samples were not different between singleton and twin pregnancies. The comparison of total iron and calcium between mothers and umbilical cord serum indicated significantly lower concentrations in the mothers, with the differences being not homogenous but rather pair-specific. A significant positive correlation between maternal serum and umbilical cord serum calcium concentration was noticed. Prenatal iron supplementation was associated with higher iron concentrations in both mothers and newborns, supporting the efficiency of supplementation and the quality of the study methods. Collectively, the data indicate no significant differences in serum iron and calcium concentrations with regard to singleton or twin pregnancies and the efficiency of iron supplementation during pregnancy for increasing iron status.

Qi-Po-Sheng-Mai granule ameliorates Ach-CaCl2 -induced atrial fibrillation by regulating calcium homeostasis in cardiomyocytes.

BACKGROUND: Atrial fibrillation (AF) is one of the most common arrhythmias encountered in clinical settings. Currently, the pathophysiology of AF remains unclear, which severely limits the effectiveness and safety of medical therapies. The Chinese herbal formula Qi-Po-Sheng-Mai Granule (QPSM) has been widely used in China to treat AF. However, its pharmacological and molecular mechanisms remain unknown. PURPOSE: The purpose of this study was to investigate the molecular mechanisms and potential targets of QPSM for AF. STUDY DESIGN AND METHODS: The AF model was induced by Ach (66 µg/ml) and CaCl2 (10 mg/kg), and the dose of 0.1 ml/100 g was injected into the tail vein for 5 weeks. QPSM was administered daily at doses of 4.42 and 8.84 g/kg, and amiodarone (0.18 g/kg) was used as the positive control. The effect of QPSM on AF was assessed by electrocardiogram, echocardiography, and histopathological analysis. Then, we employed network pharmacology with single nucleus RNA sequencing (snRNA-Seq) to investigate the molecular mechanisms and potential targets of QPSM for AF. Furthermore, high performance liquid chromatography (HPLC) method was used for component analysis of QPSM, and molecular docking was used to verify the potential targets. Using the IonOptix single cell contraction and ion synchronization test equipment, single myocyte length and calcium ion variations were observed in real time. The expression levels of calcium Transporter-related proteins were detected by western blot and immunohistochemistry. RESULTS: Based on an Ach-CaCl2-induced AF model, we found that QPSM treatment significantly reduced atrial electrical remodeling-related markers, such as AF inducibility and duration, and attenuated atrial dilation and fibrosis. Network pharmacology identified 52 active ingredients and 119 potential targets for QPSM in the treatment of AF, and 45 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched, among which calcium pathway had the greatest impact. Using single nucleus sequencing (snRNA-seq), we identified cardiomyocytes as the most differentially expressed in response to drug treatment, with nine differentially expressed genes enriched in calcium signaling pathways. High performance liquid chromatography and molecular docking confirmed that the core components of QPSM strongly bind to the key factors in the calcium signaling pathway. Additional experiments have shown that QPSM increases calcium transients (CaT) and contractility in the individual cardiomyocyte. This was accomplished by increasing the expression of CACNA1C and SERCA2a and decreasing the expression of CAMK2B and NCX1. CONCLUSION: The present study has systematically elucidated the role of QPSM in maintaining calcium homeostasis in cardiomyocytes through the regulation of calcium transporters, which could lead to new drug development ideas for AF.

Effect of electroacupuncture on calcium homeostasis in hippocampal neurons of mice with sepsis-associated encephalopathy / 中华麻醉学杂志

Objective:To investigate the effect of electroacupuncture on calcium homeostasis in hippocampal neurons of mice with sepsis-associated encephalopathy (SAE).Methods:Twenty-four healthy male C57BL/6J mice, weighing 18-22 g, were divided into 4 groups ( n=6 each) using a random number table method: sham operation group (Sham group), SAE group, SAE plus electroacupuncture group (SAE+ EA group), and SAE plus sham electroacupuncture group (SAE+ SEA group). The virus carrying calcium ion (Ca 2+ ) fluorescent probes was injected and then an optical fiber was implanted into the hippocampal CA1 area to record the fluorescence signals of Ca 2+ . SAE was induced by cecal ligation and puncture in anesthetized mice at 3 weeks after administration. Starting from 3 days before surgery, Baihui and bilateral Quchi and bilateral Zusanli acupoints were stimulated for 30 min per day for 7 consecutive days in SAE+ EA group. In SAE+ SEA group, electroacupuncture was performed at the points 0.2 mm lateral to the corresponding acupoints without electrical stimulation. Open field tests were conducted at 5 days after surgery to record the number of rearing and changes in related Ca 2+ signals in hippocampal CA1 neurons. Novel object recognition tests were conducted at 6-7 days after surgery to record the recognition time and changes in related Ca 2+ signals in hippocampal CA1 neurons. Mice were sacrificed after the end of behavioral testing on 7 days after surgery, and brain tissues ipsilateral to the optical fiber implant were obtained and the fluorescence intensity of Ca 2+ in the hippocampal CA1 neurons was acquired using a fluorescent microscope. Results:Compared with Sham group, the number of rearing and amplitudes of related Ca 2+ signals in hippocampal CA1 neurons while rearing were significantly decreased in SAE group and SAE+ SEA group ( P<0.05), and no statistically significant changes were found in the parameters mentioned above in SAE+ EA group ( P>0.05), and the recognition index and amplitudes of related Ca 2+ signals while recognizing were significantly deceased, and the fluorescence intensity of Ca 2+ in hippocampal CA1 neurons was increased in SAE, SAE+ EA and SAE+ SEA groups ( P<0.05). Compared with SAE group and SAE+ SEA group, the number of rearing and amplitudes of related Ca 2+ signals in hippocampal CA1 neurons while rearing were significantly increased, the recognition index and amplitudes of related Ca 2+ signals in hippocampal CA1 neurons while recognizing were increased, and the fluorescence intensity of Ca 2+ in hippocampal CA1 neurons was decreased in SAE+ EA group ( P<0.05). There were no statistically significant differences in the parameters mentioned above between SAE group and SAE+ SEA group ( P>0.05). Conclusions:The mechanism by which electroacupuncture alleviates SAE may be related to regulation of Ca 2+ homeostasis in hippocampal neurons of mice.

Effect of β-amyloid on calcium homeostasis and endoplasmic reticulum calcium storage of hippocampal neurons in rat / 中华行为医学与脑科学杂志

Objective:To study the effect of β-amyloid(Aβ) on calcium homeostasis and endoplasmic reticulum calcium storage of hippocampal neurons in rats.Methods:A total of 60 adult male SD rats were randomly divided into six groups by body mass matching method, with 10 rats in each group.Three groups were injected Aβ 25-35 into the hippocampus(2 μL per side), and divided into low dose group(2.5 μg/μL), medium dose group(5.0 μg/μL) and high dose group(7.5 μg/μL) respectively, and the other 3 groups were set up as the normal saline group(2 μL 0.9% sodium chloride solution), sham-operated group(rats craniotomy without injection) and normal control group(normal feeding without any treatment). The rats were fed until 14 days after operation, and the behavior and state of the rats were observed and recorded, as well as the body weight and total food intake ratio.And the rat hippocampal cells endoplasmic reticulum pathological change were observed by using the electron microscope and light microscope, meanwhile the concentration of intracellular free Ca 2+ ions was detected by the laser scanning confocal microscope and the expression level of PS, SERCA and RyR mRNA and protein by real-time PCR and Western blot methods respectively.The experimental results were analyzed using SPSS 25.0 software for statistical analysis. Repeated measurement ANOVA and one-way ANOVA were used for multi-group comparison, and Dunnett test and Tukey test were used for further pairwise comparison. Results:(1) The body weight of rats in each group was analyzed by repeated measurement ANOVA, and the difference of time effect was statistically significant( F=153.15, P<0.001), but there was no significant difference between the intergroup effects and interaction effects( F=1.547, P=0.374; F=1.598, P=0.113). The body weight of high, medium and low dose Aβ 25-35 groups at 7, 14 days after injection had no significant difference compared with the control group(all P>0.05). The food utilization rates of the high, medium and low doses of Aβ 25-35 groups were(22.9±4.0)%, (23.0±4.2)% and(22.6±3.2)%, respectively, and there was no significant difference compared with the control group((23.7±5.0)%, P>0.05). Within 14 days after injection, listlessness and lethargy were observed in rats in the high dose Aβ 25-35 group.(2) Pathological observation results showed that the endoplasmic reticulum of rat hippocampal cells in the high dose and medium dose groups of Aβ 25-35 was expanded and swelled, and the mitochondria were swollen and deformed.(3) 14 days after Aβ 25-35 injection, the fluorescence intensity of free calcium in hippocampus of rats in high, medium and low dose groups were(820.43±6.89), (720.12±4.30) and (680.50±4.32), respectively, which were all higher than that in the control group(592.17±3.97)(all P<0.001). (4) RT-PCR and Western blot results showed that compared with the control group, high dose and medium dose Aβ 25-35 injection could up-regulate the expression of PS and SERCA mRNA and protein in hippocampal cells(all P<0.05), while down-regulate the expression of RyR mRNA and protein in hippocampal cells(all P<0.05). Conclusion:The deposition of Aβ 25-35 in hippocampal tissues can disrupt the homeostasis of calcium ions in hippocampal tissues, and then cause the increase of free calcium and its related proteins, thus playing the neurotoxic role.

A Comprehensive Review on Beneficial Effects of Catechins on Secondary Mitochondrial Diseases.

Mitochondria are the main sites for oxidative phosphorylation and synthesis of adenosine triphosphate in cells, and are known as cellular power factories. The phrase "secondary mitochondrial diseases" essentially refers to any abnormal mitochondrial function other than primary mitochondrial diseases, i.e., the process caused by the genes encoding the electron transport chain (ETC) proteins directly or impacting the production of the machinery needed for ETC. Mitochondrial diseases can cause adenosine triphosphate (ATP) synthesis disorder, an increase in oxygen free radicals, and intracellular redox imbalance. It can also induce apoptosis and, eventually, multi-system damage, which leads to neurodegenerative disease. The catechin compounds rich in tea have attracted much attention due to their effective antioxidant activity. Catechins, especially acetylated catechins such as epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), are able to protect mitochondria from reactive oxygen species. This review focuses on the role of catechins in regulating cell homeostasis, in which catechins act as a free radical scavenger and metal ion chelator, their protective mechanism on mitochondria, and the protective effect of catechins on mitochondrial deoxyribonucleic acid (DNA). This review highlights catechins and their effects on mitochondrial functional metabolic networks: regulating mitochondrial function and biogenesis, improving insulin resistance, regulating intracellular calcium homeostasis, and regulating epigenetic processes. Finally, the indirect beneficial effects of catechins on mitochondrial diseases are also illustrated by the warburg and the apoptosis effect. Some possible mechanisms are shown graphically. In addition, the bioavailability of catechins and peracetylated-catechins, free radical scavenging activity, mitochondrial activation ability of the high-molecular-weight polyphenol, and the mitochondrial activation factor were also discussed.

A simple daily dynamic feeding regimen for reducing phosphorus consumption and excretion in laying hens.

Phosphorus metabolism in laying hens is a highly dynamic process over the course of the 24 h egg-laying cycle. Adjusting the phosphorus feeding regimen according to the daily egg-laying cycle may help to improve phosphorus utilization efficiency. Hy-Line Brown layers (n = 120; 70 wk old) were offered 4 different phosphorus daily regimens: (1) RR, fed regular phosphorus at both 09:00 and 17:00; (2) RL, fed regular phosphorus at 09:00 and low phosphorus at 17:00; (3) LR, fed low phosphorus at 09:00 and regular phosphorus at 17:00; (4) LL, fed low phosphorus at both 09:00 and 17:00. The regular and low phosphorus diets contained 0.32% and 0.14% non-phytate phosphorus, respectively. The feeding trial lasted for 12 wk. As a result, layers on the RL regimen had decreased laying rate (P < 0.05; 5 to 8, 9 to 12, and 1 to 12 wk) when compared to all other regimens. Layers on the LL regimen had decreased eggshell thickness and specific gravity (P < 0.05; wk 8) when compared to all other regimens, and had decreased egg shell strength (P < 0.05; wk 8) when compared to RL and LR regimens. When compared to the RR regimen (a common practice in the industry), layers on the LR regimen had: (1) identical laying performance and egg quality (P > 0.05); (2) decreased phosphorus excretion (P < 0.05) during the period of 09:00 to 17:00; (3) increased jejunal calbindin D28k protein expression (P < 0.05) 2 h after feeding in the morning; (4) decreased serum fibroblast growth factor 23 and calcitriol levels (P < 0.05), decreased jejunal type III sodium-phosphate cotransporter 2 gene and protein expression (P < 0.05), and decreased renal type III sodium-phosphate cotransporter 1 protein expression (P < 0.05), 2 h after feeding in the afternoon. In summary, when dietary phosphorus was supplemented in accordance with daily serum phosphorus rhythms (i.e., the LR regimen), laying performance and egg quality were well supported whilst significantly decreasing phosphorus consumption and excretion. Thus, serum phosphorus rhythms will need to be carefully maintained when developing dietary phosphorus-reduction strategies in laying hens.

The decrease of selenoprotein K induced by selenium deficiency in diet improves apoptosis and cell progression block in chicken liver via the PTEN/PI3K/AKT pathway.

Selenoprotein K (SELK) is imperative for normal development of chicken. It does regulate to chicken's physiological function. However, the injury of SELK-deficiency done on chicken liver and its underlying mechanism involved has not yet been covered. Therefore, we built SELK- deficiency model by feeding diet which contained low concentration of selenium (Se) to discuss SELK's regulation mechanism. Through using TUNEL, TEM, western blot and qRT-PCR we found apoptosis occurred in chicken liver in the SELK-deficiency groups. In the meanwhile, our study showed there were differentially expressed of the PTEN/PI3K/AKT pathway, calcium homeostasis, endoplasmic reticulum healthy and cell cycle progression in SELK-deficiency chicken liver tissues. In order to claim the regulation mechanism of SELK, we set SELK-knock down model in the LMH. The results in vitro were coincided with those in vivo. In the SELK-deficiency groups, the PTEN/PI3K/AKT pathway was activated and then induced ERS which eventually resulted in apoptosis in chicken liver. As the same time, the PTEN/PI3K/AKT pathway also regulated the combined effective of MDM2-p53, which leaned liver cells to G1/S blocking. Our findings support the potential of SELK in maintain the health of chicken liver, and indicate that adding proper amount of Se on the daily dietary may alleviate the deficiency of selenium.

The Multiple Effects of Vitamin D against Chronic Diseases: From Reduction of Lipid Peroxidation to Updated Evidence from Clinical Studies.

BACKGROUND: Vitamin D exerts multiple beneficial effects in humans, including neuronal, immune, and bone homeostasis and the regulation of cardiovascular functions. Recent studies correlate vitamin D with cancer cell growth and survival, but meta-analyses on this topic are often not consistent. METHODS: A systematic search of the PubMed database and the Clinical Trial Register was performed to identify all potentially relevant English-language scientific papers containing original research articles on the effects of vitamin D on human health. RESULTS: In this review, we analyzed the antioxidant and anti-inflammatory effects of vitamin D against acute and chronic diseases, focusing particularly on cancer, immune-related diseases, cardiomyophaties (including heart failure, cardiac arrhythmias, and atherosclerosis) and infectious diseases. CONCLUSIONS: Vitamin D significantly reduces the pro-oxidant systemic and tissue biomarkers involved in the development, progression, and recurrence of chronic cardiometabolic disease and cancer. The overall picture of this review provides the basis for new randomized controlled trials of oral vitamin D supplementation in patients with cancer and infectious, neurodegenerative, and cardiovascular diseases aimed at reducing risk factors for disease recurrence and improving quality of life.

Dietary nitrate increases submaximal SERCA activity and ADP transfer to mitochondria in slow-twitch muscle of female mice.

Rapid oscillations in cytosolic calcium (Ca2+) coordinate muscle contraction, relaxation, and physical movement. Intriguingly, dietary nitrate decreases ATP cost of contraction, increases force production, and increases cytosolic Ca2+, which would seemingly necessitate a greater demand for sarcoplasmic reticulum Ca2+ ATPase (SERCA) to sequester Ca2+ within the sarcoplasmic reticulum (SR) during relaxation. As SERCA is highly regulated, we aimed to determine the effect of 7-day nitrate supplementation (1 mM via drinking water) on SERCA enzymatic properties and the functional interaction between SERCA and mitochondrial oxidative phosphorylation. In soleus, we report that dietary nitrate increased force production across all stimulation frequencies tested, and throughout a 25 min fatigue protocol. Mice supplemented with nitrate also displayed an ∼25% increase in submaximal SERCA activity and SERCA efficiency (P = 0.053) in the soleus. To examine a possible link between ATP consumption and production, we established a methodology coupling SERCA and mitochondria in permeabilized muscle fibers. The premise of this experiment is that the addition of Ca2+ in the presence of ATP generates ADP from SERCA to support mitochondrial respiration. Similar to submaximal SERCA activity, mitochondrial respiration supported by SERCA-derived ADP was increased by ∼20% following nitrate in red gastrocnemius. This effect was fully attenuated by the SERCA inhibitor cyclopiazonic acid and was not attributed to differences in mitochondrial oxidative capacity, ADP sensitivity, protein content, or reactive oxygen species emission. Overall, these findings suggest that improvements in submaximal SERCA kinetics may contribute to the effects of nitrate on force production during fatigue.NEW & NOTEWORTHY We show that nitrate supplementation increased force production during fatigue and increased submaximal SERCA activity. This was also evident regarding the high-energy phosphate transfer from SERCA to mitochondria, as nitrate increased mitochondrial respiration supported by SERCA-derived ADP. Surprisingly, these observations were only apparent in muscle primarily expressing type I (soleus) but not type II fibers (EDL). These findings suggest that alterations in SERCA properties are a possible mechanism in which nitrate increases force during fatiguing contractions.

Glycomacropeptide Safety and Its Effect on Gut Microbiota in Patients with Phenylketonuria: A Pilot Study.

Glycomacropeptide (GMP) represents a good alternative protein source in Phenylketonuria (PKU). In a mouse model, it has been suggested to exert a prebiotic role on beneficial gut bacteria. In this study, we performed the 16S rRNA sequencing to evaluate the effect of 6 months of GMP supplementation on the gut microbiota of nine PKU patients, comparing their bacterial composition and clinical parameters before and after the intervention. GMP seems to be safe from both the microbiological and the clinical point of view. Indeed, we did not observe dramatic changes in the gut microbiota but a specific prebiotic effect on the butyrate-producer Agathobacter spp. and, to a lesser extent, of Subdoligranulum. Clinically, GMP intake did not show a significant impact on both metabolic control, as phenylalanine values were kept below the age target and nutritional parameters. On the other hand, an amelioration of calcium phosphate homeostasis was observed, with an increase in plasmatic vitamin D and a decrease in alkaline phosphatase. Our results suggest GMP as a safe alternative in the PKU diet and its possible prebiotic role on specific taxa without causing dramatic changes in the commensal microbiota.

Rhynchophylline Regulates Calcium Homeostasis by Antagonizing Ryanodine Receptor 2 Phosphorylation to Improve Diabetic Cardiomyopathy.

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes that can lead to heart failure and death, for which there is no effective treatment. Rhynchophylline (Rhy) is the main effective component of the Chinese herbal medicine Uncaria rhynchophylla, which mainly acts on the cardiovascular and nervous systems. However, its role in protecting against DCM remains unexplored. The present study sought to reveal the mechanism of Rhy in improving type 2 diabetes mellitus (T2DM) myocardial lesions from the perspective of regulating calcium homeostasis in cardiomyocytes. We prepared a mouse model of T2DM using a high-fat diet combined with low doses of streptozotocin. The T2DM mice were given 40 mg/kg of Rhy for 8 weeks. The results showed that Rhy can attenuate cardiac pathological changes, slow down the heart rate, decrease serum cardiac enzyme levels, reduce cardiomyocyte apoptosis, enhance cardiomyocyte contractility, and raise the calcium transient amplitude in T2DM mice. Further, Rhy downregulated the phosphorylation level of ryanodine receptor 2, upregulated the phosphorylation level of phospholamban, protected mitochondrial structure and function, and increased adenosine triphosphate levels in the cardiac tissue of T2DM mice. Our results demonstrated that Rhy may protect against myocardial damage in T2DM mice and promote cardiomyocyte contraction, and its mechanism of action seems to be related to the regulation of intracellular calcium homeostasis.

Effects of feeding 25-hydroxyvitamin D3 with an acidogenic diet during the prepartum period in dairy cows: Mineral metabolism, energy balance, and lactation performance of Holstein dairy cows.

Our objective was to determine the effects of feeding 25-hydroxyvitamin D3 [25(OH)D3], or vitamin D3 (cholecalciferol) on plasma, mineral, and metabolite concentrations, mineral balance, mineral excretion, rumination, energy balance, and milk production of dairy cows. We hypothesized that supplementing 3 mg/d of 25(OH)D3 during the prepartum period would be more effective than supplementing vitamin D3 at the National Research Council (2001) levels to minimize calcium imbalance during the transition period and improve milk production of dairy cows. Forty multiparous, pregnant nonlactating-Holstein cows were enrolled in this study. Body weight, body condition score, parity, and milk yield in the previous lactation (mean ± standard deviation) were 661 ± 59.2, 3.46 ± 0.35, 1.79 ± 0.87, and 33.2 ± 6.43 kg/d, respectively. Cows were enrolled into the blocks (n = 20 for each treatment) at 30 d of the expected day of calving to receive an acidogenic diet (373 g/kg of neutral detergent fiber and 136 g/kg of crude protein, dry matter basis; -110 mEq/kg) associated with the treatments: (1) control (CTRL), vitamin D3 at 0.625 mg/d (equivalent to 25,000 IU of vitamin D3/d) or (2) 25(OH)D3 at 3 mg/d (equivalent to 120,000 IU of vitamin D3/d). All cows were fed with the base ration for 49 d after calving. Blood samples were taken on d 7, 0, 1, 2, 21, and 42, relative to calving. No effect of treatment was observed for prepartum dry matter intake or body condition score. A trend for increase of ionized Ca was observed for the cows fed 25(OH)D3, compared with the CTRL, but no effect of treatment was detected for total Ca or total P. Feeding 25(OH)D3 increased colostrum yield. The plasmatic concentration of 25-hydroxyvitamin D3 was increased with 25(OH)D3 supplementation. 25-Hydroxyvitamin D3 supplementation increased plasma glucose concentration at parturition. The postpartum dry matter intake was not influenced by treatments. Feeding 25(OH)D3 increases milk yield, 3.5% fat-corrected milk, and energy-corrected milk and improves milk yield components in early lactation. Overall, these findings suggest that 25(OH)D3 at 3 mg/d can improve the energy metabolism and lactation performance, compared with the current-feeding practice of supplementing vitamin D3 at 0.625 mg/d.

Calcium Homeostasis in the Epididymal Microenvironment: Is Extracellular Calcium a Cofactor for Matrix Gla Protein-Dependent Scavenging Regulated by Vitamins.

In the male reproductive tract, the epididymis is an essential organ for sperm maturation, in which sperm cells acquire mobility and the ability to fertilize oocytes while being stored in a protective microenvironment. Epididymal function involves a specialized luminal microenvironment established by the epithelial cells of epididymal mucosa. Low-calcium concentration is a unique feature of this epididymal luminal microenvironment, its relevance and regulation are, however, incompletely understood. In the rat epididymis, the vitamin D-related calcium-dependent TRPV6-TMEM16A channel-coupler has been shown to be involved in fluid transport, and, in a spatially complementary manner, vitamin K2-related γ-glutamyl carboxylase (GGCX)-dependent carboxylation of matrix Gla protein (MGP) plays an essential role in promoting calcium-dependent protein aggregation. An SNP in the human GGCX gene has been associated with asthenozoospermia. In addition, bioinformatic analysis also suggests the involvement of a vitamin B6-axis in calcium-dependent MGP-mediated protein aggregation. These findings suggest that vitamins interact with calcium homeostasis in the epididymis to ensure proper sperm maturation and male fertility. This review article discusses the regulation mechanisms of calcium homeostasis in the epididymis, and the potential role of vitamin interactions on epididymal calcium homeostasis, especially the role of matrix calcium in the epididymal lumen as a cofactor for the carboxylated MGP-mediated scavenging function.

Involvement of calcium homeostasis and unfolded protein response in autophagy co-induced by molybdenum and cadmium in duck (Anas platyrhyncha) brain.

Excess molybdenum (Mo) and cadmium (Cd) are harmful to animals, but neurotoxicity caused by Mo and Cd co-exposure in ducks is yet unknown. To assess joint impacts of Mo and Cd on autophagy via calcium homeostasis and unfolded protein response (UPR) in duck brain, 40 healthy 7-day-old ducks (Anas platyrhyncha) were assigned to 4 groups at random and fed diets supplemented with different doses of Mo or/and Cd for 16 weeks, respectively. Brain tissues were excised for experiment. Results exhibited that Mo or/and Cd disturbed calcium homeostasis by decreased ATPase activities and increased calcium (Ca) content, and upregulated calcium homeostasis-related factors Ca2+/CAM-dependent kinase IIɑ (CaMKIIɑ), calcineurin (CaN), inositol-1,4,5-trisphosphate receptor (IP3R), and calreticulin (CRT) expression levels. Meanwhile, the upregulation of UPR-related factor expression levels indicated that Mo or/and Cd activated UPR. Moreover, Mo or/and Cd triggered autophagy through promoting the number of autophagosomes and LC3II immunofluorescence intensity and altering autophagy key factor expression levels. Correlation analysis showed that there were obvious connections among Ca2+ homeostasis, endoplasmic reticulum (ER) stress, and autophagy induced by Mo or/and Cd. Thence, it can be speculated that autophagy initiated by Mo or/and Cd may be associated with interfering Ca2+ homeostasis and triggering UPR.

Inhibitory Effects of 6,8-Diprenylorobol on Endometriosis Progression in Humans by Disrupting Calcium Homeostasis and Mitochondrial Function.

6,8-Diprenylorobol is a flavonoid compound extracted from Cudrania tricuspidata. It has various biological functions, such as inhibiting melanin synthesis and inducting cell death in cancerous cells. In addition, Cudrania tricuspidata is known to be effective in female diseases, and previous studies have shown anticancer effects in cervical cancer, a female reproductive disease. Outside of that, Cudrania tricuspidata has various physiological effects. However, the effect of 6,8-diprenylorobol is not well known in other benign and chronic diseases, even in endometriosis, which commonly arises in the female reproductive tract. In the present study, we determined the inhibitory effects of 6,8-diprenylorobol on the growth of endometriosis VK2/E6E7 and End1/E6E7 cells. Results indicated that 6,8-diprenylorobol suppressed cellular proliferation and increased the disruption of the cell cycle, mitochondrial membrane potential (MMP), generation of reactive oxygen species, and Ca2+ homeostasis in both endometriosis cells. However, the proliferation of normal stromal cells isolated from endometrial tissue was not altered by 6,8-diprenylorobol. The change in Ca2+ levels was estimated in fluo-4- or rhod-2-stained VK2/E6E7 and End1/E6E7 cells after the treatment of the intracellular calcium regulators 2-aminoethoxydiphenyl borate (2-APB) and ruthenium red (RUR) with 6,8-diprenylorobol. A combination of 6,8-diprenylorobol with each regulator decreased the calcium accumulation in endometriosis cells. Furthermore, Western blot analysis indicated that 6,8-diprenylorobol inactivated AKT pathways, whereas it activated P38 MAPK pathways. In addition, 6,8-diprenylorobol decreased mitochondrial respiration, leading to the reduction in ATP production in VK2/E6E7 and End1/E6E7 cells. Collectively, our results suggested that 6,8-diprenylorobol might be a potential therapeutic agent or adjuvant therapy for the management of endometriosis.

Assessing the Potential of Nutraceuticals as Geroprotectors on Muscle Performance and Cognition in Aging Mice.

Aging and frailty are associated with a decline in muscle force generation, which is a direct consequence of reduced muscle quantity and quality. Among the leading contributors to aging is the generation of reactive oxygen species, the byproducts of terminal oxidation. Their negative effects can be moderated via antioxidant supplementation. Krill oil and astaxanthin (AX) are nutraceuticals with a variety of health promoting, geroprotective, anti-inflammatory, anti-diabetic and anti-fatigue effects. In this work, we examined the functional effects of these two nutraceutical agents supplemented via pelleted chow in aging mice by examining in vivo and in vitro skeletal muscle function, along with aspects of intracellular and mitochondrial calcium homeostasis, as well as cognition and spatial memory. AX diet regimen limited weight gain compared to the control group; however, this phenomenon was not accompanied by muscle tissue mass decline. On the other hand, both AX and krill oil supplementation increased force production without altering calcium homeostasis during excitation-contraction coupling mechanism or mitochondrial calcium uptake processes. We also provide evidence of improved spatial memory and learning ability in aging mice because of krill oil supplementation. Taken together, our data favors the application of antioxidant nutraceuticals as geroprotectors to improve cognition and healthy aging by virtue of improved skeletal muscle force production.

Polymorphisms Contributing to Calcium Status: A Systematic Review.

This systematic review assessed genotypes and changes in calcium homeostasis. A literature search was performed in EMBASE, Medline and CENTRAL on 7 August 2020 identifying 1012 references. Studies were included with any human population related to the topic of interest, and genetic variations in genes related to calcium metabolism were considered. Two reviewers independently screened references, extracted relevant data and assessed study quality using the Q-Genie tool. Forty-one studies investigating Single Nucleotide Polymorphisms (SNPs) in relation to calcium status were identified. Almost half of the included studies were of good study quality according to the Q-Genie tool. Seventeen studies were cross-sectional, 14 case-control, seven association and three were Mendelian randomization studies. Included studies were conducted in over 18 countries. Participants were mainly adults, while six studies included children and adolescents. Ethnicity was described in 31 studies and half of these included Caucasian participants. Twenty-six independent studies examined the association between calcium and polymorphism in the calcium-sensing receptor (CASR) gene. Five studies assessed the association between polymorphisms of the Vitamin D receptor (VDR) gene and changes in calcium levels or renal excretion. The remaining ten studies investigated calcium homeostasis and other gene polymorphisms such as the CYP24A1 SNP or CLDN14. This study identified several CASR, VDR and other gene SNPs associated with calcium status. However, to provide evidence to guide dietary recommendations, further research is needed to explore the association between common polymorphisms and calcium requirements.