Lower Serum Calcium as a Potentially Associated Factor for Conversion of Mild Cognitive Impairment to Early Alzheimer's Disease in the Japanese Alzheimer's Disease Neuroimaging Initiative

Serum calcium improves the relationship between fluoride exposure and hypothalamic-pituitary-testicular axis hormones levels in males-a cross-sectional study on farmers in the lower reaches of the Yellow River

Numerous studies have reported the toxicity of fluoride to the male reproductive system, but epidemiological evidence is limited. We conducted a cross-sectional study in Kaifeng City, Henan Province in 2011 to explore the association between fluoride exposure and hypothalamic-pituitary-testicular (HPT) axis hormones in men. Morning urinary fluoride (UF), serum HPT axis hormones and serum calcium (SC) concentrations were detected. Percent changes and 95% confidence intervals in HPT axis hormones associated with UF were estimated using adjusted linear regression models, and performed subgroup analysis based on SC levels. The restricted cubic spline model was used to fit nonlinear relationships. For every 10% increase in UF, the concentrations of serum GnRH, T, SHBG and TSI decreased by 2.13%, 2.39%, 2.19% and 1.96%, while E2 and FEI increased by 1.11% and 3.33%. Subgroup analysis showed that for every 10% increase in UF, the levels of GnRH, T, TSI and FTI decreased by approximately 3.15%, 5.49%, 4.47% and 5.14%, while the E2 level increased by 2.92% in low-serum-calcium group (LCG). The levels of GnRH and T decreased by approximately 2.97% and 1.82% in medium-serum-calcium group (MCG). In high-serum-calcium group (HCG), serum SHBG levels decreased by 4.70%, while FTI and FEI levels increased by 4.93% and 4.20% as UF concentration increased (P < 0.05, respectively). The non-linear relationship between serum GnRH and UF concentrations presented an approximately inverted U-shaped curve, with a turning point UF concentration of 1.164 mg/L (P < 0.001), and their nonlinear relationship in LCG and MCG were similar to that in the overall subjects. In conclusion, excessive exposure to fluoride can interfere with male serum HPT axis hormones, and a moderate increase in SC alleviates the effect of fluoride. Prospective cohort studies are essential to confirm the causality.

The Concurrent Association of Magnesium and Calcium Deficiencies with Cognitive Function in Older Hospitalized Adults

Background/Objectives: Hypomagnesemia and hypocalcemia are common conditions among older adults that may contribute to cognitive decline. However, most of the existing research has focused primarily on dietary intake rather than the actual serum levels of these nutrients or examined them separately. This study aims to investigate the relationship between hypomagnesemia, hypocalcemia, and the concurrent presence of both deficiencies in relation to cognitive performance among seniors. Methods: A total of 1220 hospitalized patients aged 60 and older were included in the analysis. The participants were categorized into four groups: those with normal serum levels of magnesium and calcium, those with hypomagnesemia, those with hypocalcemia, and those with both serum magnesium and calcium deficiencies. To evaluate the potential influence of age, sex, common comorbidities, and disturbances in magnesium and calcium levels on cognitive performance, two general linear models were employed, using the Mini-Mental State Examination (MMSE) and Clock-Drawing Test (CDT) as dependent variables. Results: After adjusting for age, sex, body mass index, and comorbidities, the mean values for the MMSE and CDT were 23.33 (95%CI: 22.89-23.79) and 5.56 (95%CI: 5.29-5.83) for the group with normomagnesemia and normocalcemia, 22.59 (95%CI: 21.94-23.24) and 5.16 (95%CI: 4.77-5.54) for the group with hypomagnesemia, 19.53 (95%CI: 18.36-20.70) and 4.52 (95%CI: 3.83-5.21) for the group with hypocalcemia, and 21.14 (95%CI 19.99-22.29) and 4.28 (95%CI 3.61-4.95) for the group with both hypomagnesemia and hypocalcemia, respectively. Magnesium and calcium deficiencies contributed to MMSE and CDT variance in the general linear models. Conclusions: Our findings indicate that in addition to age, body mass index, and chronic heart failure, both hypomagnesemia and hypocalcemia are associated with reduced cognitive performance.

Outcome of resveratrol and resveratrol with donepezil combination on the β-amyloid plaques and neurofibrillary tangles in Alzheimer's disease

The goal of this research was to study the effect of different doses of resveratrol (RS) and RS with donepezil (DPZ) on the deposition of amyloid beta (Aβ) and neurofibrillary tangles (NFTs) in colchicine-induced Alzheimer's disease (AD) brain. The study included three months old male Albino Wistar rats and consisted of six animal groups: AD model (group 1), treatment groups, RS 10 mg/kg body weight (group 2), RS 20 mg/kg body weight (group 3), RS 10 mg/kg body weight along with DPZ 1 mg/kg body weight (group 6), prophylaxis groups, RS 10 mg/kg body weight (group 4) and RS 20 mg/kg body weight (group 5). In the treatment groups, RS was given for 7 consecutive days from the day of induction of AD, and in the prophylaxis groups, we started RS 7 days even before the induction of AD and continued for seven days after the induction. The number of Aβs and NFTs at the frontal region, cornu ammonis (CA) 1,2,3,4 and dentate gyrus regions of hippocampus were evaluated. The immunohistochemical analysis was performed by using mouse anti-β-amyloid antibody for the Aβ plaques and polyclonal rabbit anti-human tau for the tau-positive neurons. The present study observed the accumulation of Aβ plaques and tau-positive neurons in the AD model. However, their numbers were significantly decreased in the treatment groups (p < 0.001). The best results were observed when RS 10 mg was given prophylactically (p < 0.01) and RS along with DPZ (p < 0.001), suggesting the neuroprotective effect of RS and its synergistic effect with the DPZ.

Data-driven Stochastic Model for Quantifying the Interplay Between Amyloid-beta and Calcium Levels in Alzheimer's Disease

The abnormal aggregation of extracellular amyloid-β ( A β ) in senile plaques resulting in calcium C a + 2 dyshomeostasis is one of the primary symptoms of Alzheimer's disease (AD). Significant research efforts have been devoted in the past to better understand the underlying molecular mechanisms driving A β deposition and C a + 2 dysregulation. Importantly, synaptic impairments, neuronal loss, and cognitive failure in AD patients are all related to the buildup of intraneuronal A β accumulation. Moreover, increasing evidence show a feed-forward loop between A β and C a + 2 levels, i.e. A β disrupts neuronal C a + 2 levels, which in turn affects the formation of A β . To better understand this interaction, we report a novel stochastic model where we analyze the positive feedback loop between A β and C a + 2 using ADNI data. A good therapeutic treatment plan for AD requires precise predictions. Stochastic models offer an appropriate framework for modelling AD since AD studies are observational in nature and involve regular patient visits. The etiology of AD may be described as a multi-state disease process using the approximate Bayesian computation method. So, utilizing ADNI data from 2-year visits for AD patients, we employ this method to investigate the interplay between A β and C a + 2 levels at various disease development phases. Incorporating the ADNI data in our physics-based Bayesian model, we discovered that a sufficiently large disruption in either A β metabolism or intracellular C a + 2 homeostasis causes the relative growth rate in both C a + 2 and A β , which corresponds to the development of AD. The imbalance of C a + 2 ions causes A β disorders by directly or indirectly affecting a variety of cellular and subcellular processes, and the altered homeostasis may worsen the abnormalities of C a + 2 ion transportation and deposition. This suggests that altering the C a + 2 balance or the balance between A β and C a + 2 by chelating them may be able to reduce disorders associated with AD and open up new research possibilities for AD therapy.

Metals in Alzheimer's Disease

The role of metals in the pathogenesis of Alzheimer's disease (AD) is still debated. Although previous research has linked changes in essential metal homeostasis and exposure to environmental heavy metals to the pathogenesis of AD, more research is needed to determine the relationship between metals and AD. In this review, we included human studies that (1) compared the metal concentrations between AD patients and healthy controls, (2) correlated concentrations of AD cerebrospinal fluid (CSF) biomarkers with metal concentrations, and (3) used Mendelian randomization (MR) to assess the potential metal contributions to AD risk. Although many studies have examined various metals in dementia patients, understanding the dynamics of metals in these patients remains difficult due to considerable inconsistencies among the results of individual studies. The most consistent findings were for Zn and Cu, with most studies observing a decrease in Zn levels and an increase in Cu levels in AD patients. However, several studies found no such relation. Because few studies have compared metal levels with biomarker levels in the CSF of AD patients, more research of this type is required. Given that MR is revolutionizing epidemiologic research, additional MR studies that include participants from diverse ethnic backgrounds to assess the causal relationship between metals and AD risk are critical.

Preoperative serum calcium could be a prognostic factor for surgical treatment of recurrent patellar dislocation: a retrospective study

Background

Surgical treatment for recurrent patellar dislocation (RPD) could yield good outcomes. While, unsatisfactory recovery still exists in some cases. For all prognostic factors, serum biomarkers have rarely been investigated. This study aimed to evaluate the prognostic value of preoperative serum calcium level, a widely used serum biomarker, in surgical treatment for RPD.

Study design

Retrospective study.

Methods

Ninety-nine patients with RPD were enrolled in the study. Preoperative serum calcium was acquired from routinely tested blood 1 day prior to operation. Demographic data, characteristics of RPD, postoperative functional outcomes were obtained. The association between preoperative calcium and postoperative functional outcomes (Kujala, Lysholm, Tegner, IKDC and KOOS score) was determined by correlation analysis and multivariate linear regression analysis. Poor recovery was determined as Kujala score below 80. The receiver operating characteristic (ROC) curve was used to assess the prognostic value of preoperative calcium.

Results

Patients were followed up for a mean period of 2.45 ± 1.33 years. All clinical scores showed significant improvement at the latest follow-up. Correlation and multivariate linear analyses indicated that serum calcium level was an important factor related with the prognosis of surgical treatment for RPD. According to the ROC curve, the cut-off value for preoperative calcium was 2.225 mmol/L. The clinical outcomes of patients with a preoperative blood calcium < 2.225 mmol/L was significantly worse than that with a higher calcium level. The correspondent sensitivity was 0.812 with a specificity of 0.633.

Conclusion

Operative treatment for RPD achieved good results, while in some cases the functional scores remain inferior. As a serum biomarker, preoperative calcium could be prognostic for outcomes after surgical treatment for RPD.

Analysis of the Relationship among Cognitive Impairment, Nutritional Indexes and the Clinical Course among COVID-19 Patients Discharged from Hospital—Preliminary Report

Numerous data indicate the presence of cognitive impairment in people who have undergone COVID-19, often called COVID Fog (CF). This phenomenon persists even 6 months after infection, and its etiology and pathogenesis are not fully known. The aim of this article was to analyze the relationship among cognitive functioning, clinical data and nutrition indexes in patients discharged from the COVID-19 hospital of the Military Institute of Medicine, Warsaw, Poland. The sample comprised 17 individuals—10 women and 7 men, with ages of 65 ± 14 years. Cognitive impairment was measured with the use of the Montreal Cognitive Assessment (MoCA). The nutrition parameters included: hemoglobin, red blood cells, total cholesterol and its fractions, triglycerides, total protein, albumin, urea, creatinine, phosphates, calcium and sodium. The analysis showed that albumin concentration significantly correlated with the total MoCA score and especially with the short-term memory test score. Conversely, total cholesterol, and especially LDL concentrations, were highly and negatively associated with the MoCA score. In conclusion: markers of nutritional status are correlated with the severity of CF. Individuals with malnutrition or risk of malnutrition should be screened for CF. Further studies need to be performed in this area.

Effect of Resveratrol Combined with Donepezil Hydrochloride on Inflammatory Factor Level and Cognitive Function Level of Patients with Alzheimer's Disease

Objective

To explore the effect of resveratrol (RES) combined with donepezil hydrochloride on inflammatory factor level and cognitive function level of patients with Alzheimer's disease (AD).

Methods

A total of 90 AD patients treated in our hospital from June 2019 to June 2020 were selected as the study objects and divided into the control group (CG) and experimental group (EG) by the randomized and double-blind method, with 45 cases each. Patients in CG received donepezil hydrochloride treatment, and on this basis, those in EG received additional RES treatment, so as to compare the clinical indicators between the two groups.

Results

Compared with CG after treatment, EG obtained significantly higher good rate, MMSE score, and FIM score (P < 0.05) and obviously lower clinical indicators and ADAS-cog score (P < 0.001), and between CG and EG, no obvious difference in total incidence rate of adverse reactions was observed after treatment (P > 0.05).

Conclusion

Combining RES with donepezil hydrochloride has significant clinical efficacy in treating AD, which can effectively improve patients' inflammatory factor indicators, promote their cognitive function, and facilitate patient prognosis.

Biomarkers used in Alzheimer's disease diagnosis, treatment, and prevention

Alzheimer's disease (AD), being the number one in terms of dementia burden, is an insidious age-related neurodegenerative disease and is presently considered a global public health threat. Its main histological hallmarks are the Aβ senile plaques and the P-tau neurofibrillary tangles, while clinically it is marked by a progressive cognitive decline that reflects the underlying synaptic loss and neurodegeneration. Many of the drug therapies targeting the two pathological hallmarks namely Aβ and P-tau have been proven futile. This is probably attributed to the initiation of therapy at a stage where cognitive alterations are already obvious. In other words, the underlying neuropathological changes are at a stage where these drugs lack any therapeutic value in reversing the damage. Therefore, there is an urgent need to start treatment in the very early stage where these changes can be reversed, and hence, early diagnosis is of primordial importance. To this aim, the use of robust and informative biomarkers that could provide accurate diagnosis preferably at an earlier phase of the disease is of the essence. To date, several biomarkers have been established that, to a different extent, allow researchers and clinicians to evaluate, diagnose, and more specially exclude other related pathologies. In this study, we extensively reviewed data on the currently explored biomarkers in terms of AD pathology-specific and non-specific biomarkers and highlighted the recent developments in the diagnostic and theragnostic domains. In the end, we have presented a separate elaboration on aspects of future perspectives and concluding remarks.

Health Effects of Calcium: Evidence From Mendelian Randomization Studies

Calcium is widely used in conjunction with vitamin D to prevent osteoporosis. The use of calcium supplementation is also promoted for its potential benefits in lowering the risk for metabolic syndromes and cancers. However, the causal link between calcium and various health outcomes remains unclear. This review focuses on the evidence from 24 Mendelian randomization (MR) studies that were designed to minimize bias from confounding and reverse causation. These MR studies evaluated the effect of lifelong genetically higher serum calcium levels on various health outcomes. Overall, available MR studies found no conclusive effects of serum calcium levels on bone mineral density and fracture, ischemic stroke and heart failure, cancers, type 2 diabetes, Parkinson disease, or offspring birth weight. However, a higher serum calcium concentration was reported to have estimated causal effects on increased risks for coronary artery disease (especially myocardial infarction), migraine, renal colic, allergy/adverse effect of penicillin, and reduced risks for osteoarthrosis and osteoarthritis. In conclusion, supplementation of calcium in individuals from the general population is not predicted to influence the risk of most investigated diseases to date. Moreover, long-term high serum calcium concentrations may result in adverse health outcomes. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

An Updated Mendelian Randomization Analysis of the Association Between Serum Calcium Levels and the Risk of Alzheimer's Disease

It has been a long time that the relationship between serum calcium levels and Alzheimer’s disease (AD) remains unclear. Until recently, observational studies have evaluated the association between serum calcium levels and the risk of AD, however, reported inconsistent findings. Meanwhile, a Mendelian randomization (MR) study had been conducted to test the causal association between serum calcium levels and AD risk, however, only selected 6 serum calcium SNPs as the instrumental variables. Hence, these findings should be further verified using additional more genetic variants and large-scale genome-wide association study (GWAS) dataset to increase the statistical power. Here, we conduct an updated MR analysis of the causal association between serum calcium levels and the risk of AD using a two-stage design. In discovery stage, we conducted a MR analysis using 14 SNPs from serum calcium GWAS dataset (N = 61,079), and AD GWAS dataset (N = 63,926, 21,982 cases, 41,944 cognitively normal controls). All four MR methods including IVW, weighted median, MR-Egger, and MR-PRESSO showed a reduced trend of AD risk with the increased serum calcium levels. In the replication stage, we performed a MR analysis using 166 SNPs from serum calcium GWAS dataset (N = 305,349), and AD GWAS dataset (N = 63,926, 21,982 cases, 41,944 cognitively normal controls). Only the weighted median indicated that genetically increased serum calcium level was associated with the reduced risk of AD. Hence, additional studies are required to investigate these findings.

Calcium: More Than Bone? Implications for Clinical Practice and Theory

Serum calcium is routinely screened, but rarely scrutinized in the context of normal, physiologic functioning. This brief review strives to explore the implications of serum calcium, suggests guidelines for its interpretation, and discusses the implications of high, low, and “normocalcemia” in the clinical setting. We find that serum Ca²⁺ concentrations are a valuable prognostic indicator in routine metabolic workups and advocate for greater attention, on behalf of the provider, to variations in a patient’s calcemic status. Variations in calcemic status are primarily tied to malignancy, impaired parathyroid hormone (PTH) secretion, defects in vitamin D synthesis, insulin-like growth factor 1 (IGF-1) fluctuation, genetic syndromes (DiGeorge syndrome) and calcium-sensing receptor (CaSR) mutation. Prognostic implications for high and low serum Ca²⁺ include, but are not limited to, increased thromboembolic and major adverse cardiovascular event (MACE) risk, cardiac remodeling, hypertension, cognitive decline, and insulin resistance.

Serum Calcium Predicts Cognitive Decline and Clinical Progression of Alzheimer's Disease

Relationship between serum calcium and Alzheimer's disease (AD) remains unclear. The aim of this study is to test whether serum calcium is associated with other AD-associated biomarkers and could predict clinical progression in nondemented elders. This was a longitudinal population-based study. The sample was derived from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort, which included 1224 nondemented elders: 413 cognitively normal (CN) and 811 mild cognition impairment (MCI). Associations were investigated between serum calcium and longitudinal changes in Aβ/tau pathologic features, brain structure, cognitive function, and disease progression. Serum calcium concentrations increased with disease severity. Serum calcium predicted longitudinal cognitive decline and conversion from nondemented status to AD dementia (adjusted HR = 1.41, 95% CI 1.13-1.76). Furthermore, serum calcium levels were negatively correlated with CSF-Aβ₄₂ (β = - 0.558, P = 0.008), FDG-PET (β = - 0.292, P < 0.001), whole brain volume (β = - 0.148, P = 0.001), and middle temporal volume (β = - 0.216, P = 0.042). Similar results were obtained in CN and MCI groups. Higher serum calcium status (even if not hypercalcemia) may increase the risk of AD in elders. Serum calcium is a useful biomarker in predicting clinical progression in nondemented elders. More researches are needed in the future to explore the underlying mechanism.

Therapeutic Potential of Porcine Liver Decomposition Product: New Insights and Perspectives for Microglia-Mediated Neuroinflammation in Neurodegenerative Diseases

It is widely accepted that microglia-mediated inflammation contributes to the progression of neurodegenerative diseases; however, the precise mechanisms through which these cells contribute remain to be elucidated. Microglia, as the primary immune effector cells of the brain, play key roles in maintaining central nervous system (CNS) homeostasis. Microglia are located throughout the brain and spinal cord and may account for up to 15% of all cells in the brain. Activated microglia express pro-inflammatory cytokines that act on the surrounding brain and spinal cord. Microglia may also play a detrimental effect on nerve cells when they gain a chronic inflammatory function and promote neuropathologies. A key feature of microglia is its rapid morphological change upon activation, characterized by the retraction of numerous fine processes and the gradual acquisition of amoeba-like shapes. These morphological changes are also accompanied by the expression and secretion of inflammatory molecules, including cytokines, chemokines, and lipid mediators that promote systemic inflammation during neurodegeneration. This may be considered a protective response intended to limit further injury and initiate repair processes. We previously reported that porcine liver decomposition product (PLDP) induces a significant increase in the Hasegawa’s Dementia Scale-Revised (HDS-R) score and the Wechsler Memory Scale (WMS) in a randomized, double-blind, placebo-controlled study in healthy humans. In addition, the oral administration of porcine liver decomposition product enhanced visual memory and delayed recall in healthy adults. We believe that PLDP is a functional food that aids cognitive function. In this review, we provide a critical assessment of recent reports of lysophospholipids derived from PLDP, a rich source of phospholipids. We also highlight some recent findings regarding bidirectional interactions between lysophospholipids and microglia and age-related neurodegenerative diseases such as dementia and Alzheimer’s disease.

Impact of Serum Calcium Levels on Alzheimer's Disease: A Mendelian Randomization Study

BACKGROUND

Altered calcium homeostasis is hypothesized to underlie Alzheimer's disease (AD). However, it remains unclear whether serum calcium levels are genetically associated with AD risk.

OBJECTIVE

To develop effective therapies, we should establish the causal link between serum calcium levels and AD.

METHODS

Here, we performed a Mendelian randomization study to investigate the causal association of increased serum calcium levels with AD risk using the genetic variants from a large-scale serum calcium genome-wide association study (GWAS) dataset (61,079 individuals of European descent) and a large-scale AD GWAS dataset (54,162 individuals including 17,008 AD cases and 37,154 controls of European descent). Here, we selected the inverse-variance weighted (IVW) as the main analysis method. Meanwhile, we selected other three sensitivity analysis methods to examine the robustness of the IVW estimate.

RESULTS

IVW analysis showed that the increased serum calcium level (per 1 standard deviation (SD) increase 0.5 mg/dL) was significantly associated with a reduced AD risk (OR = 0.57, 95% CI 0.35-0.95, p = 0.031). Meanwhile, all the estimates from other sensitivity analysis methods were consistent with the IVW estimate in terms of direction and magnitude.

CONCLUSION

In summary, we provided evidence that increased serum calcium levels could reduce the risk of AD. Meanwhile, randomized controlled study should be conducted to clarify whether diet calcium intake or calcium supplement, or both could reduce the risk of AD.

Visualizing modules of coordinated structural brain atrophy during the course of conversion to Alzheimer's disease by applying methodology from gene co-expression analysis

Objective

We aimed to identify modularized structural atrophy of brain regions with a high degree of connectivity and its longitudinal changes associated with the progression of Alzheimer's disease (AD) using weighted gene co-expression network analysis (WGCNA), which is an unsupervised hierarchical clustering method originally used in genetic analysis.

Methods

We included participants with late mild cognitive impairment (MCI) at baseline from the Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI) study. We imputed normalized and Z-transformed structural volume or cortical thickness data of 164 parcellated brain regions/structures based on the calculations of the FreeSurfer software. We applied the WGCNA to extract modules with highly interconnected structural atrophic patterns and examined the correlation between the identified modules and clinical AD progression.

Results

We included 204 participants from the baseline dataset, and performed a follow-up with 100 in the 36-month dataset of MCI cohort participants from the J-ADNI. In the univariate correlation or variable importance analysis, baseline atrophy in temporal lobe regions/structures significantly predicted clinical AD progression. In the WGCNA consensus analysis, co-atrophy modules associated with MCI conversion were first distributed in the temporal lobe and subsequently extended to adjacent parietal cortical regions in the following 36 months.

Conclusions

We identified coordinated modules of brain atrophy and demonstrated their longitudinal extension along with the clinical course of AD progression using WGCNA, which showed a good correspondence with previous pathological studies of the tau propagation theory. Our results suggest the potential applicability of this methodology, originating from genetic analyses, for the surrogate visualization of the underlying pathological progression in neurodegenerative diseases not limited to AD.

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Applying origin-of-genetic unsupervised clustering to structural MRI from J-ADNI.

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We identified highly-interconnected modules associated with AD progression.

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Extension of co-atrophy modules corresponded with tau propagation theory in AD.

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This method has potential for visualizing underlying pathological progression.

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Application to other neurodegenerative diseases not limited to AD is expected.