Insulin resistance in patients with recurrent pregnancy loss is associated with lymphocyte population aberration

This study was designed to investigate the relationship of insulin resistance (IR) and cellular immune abnormalities associated with women with recurrent pregnancy loss (RPL). Women with RPL were divided into two groups according to their homeostasis model assessment for IR (HOMA-IR) scores. The IR group received metformin approximately 3 months before pregnancy. The percentage of lymphocyte subsets and other blood biochemical indices were tested. The HOMA-IR and fasting serum insulin levels were related to the percentage of lymphocyte subsets. The women with RPL had higher CD3⁺ and CD3⁺CD4⁺ cell levels while CD56⁺CD16⁺cell levels were lower. A higher likelihood of cellular immune abnormalities was observed. Women with normal lymphocyte subsets had normal pregnancy outcomes. Metformin significantly downregulated CD3⁺ and CD3⁺CD4⁺ cells and improved pregnancy outcomes. IR was associated with cellular immune abnormalities in RPL. The data suggests that metformin affected the immune/inflammatory response, which may regulate the cellular immune balance and improve pregnancy outcomes. Abbreviations RPL: recurrent pregnancy loss; IR insulin resistance; HOMA-IR: homeostasis model assessment for IR.

Thymic stromal lymphopoietin contribution to the recruitment of circulating fibrocytes to the lung in a mouse model of chronic allergic asthma

Objective: Fibrocyte localization to the airways and thymic stromal lymphopoietin (TSLP) overexpression in the lung are features of severe asthma. The aim of this study was to determine whether TSLP contributes to fibrocyte trafficking and airway remodeling in a mouse model of allergic asthma. Methods: We established a chronic asthma animal model by administering house dust mite (HDM) extracts intranasally for up to 5 consecutive weeks. Mouse anti-TSLP monoclonal antibody (mAb) was given intraperitoneally starting the 4^th week. Fluorescence-labeled CD34/collagen I (Col I)-dual-positive fibrocytes were examined by confocal microscopy. The level of TGF-β1 in the bronchoalveolar lavage (BAL) fluid was determined by ELISA. Results: We found significantly increased levels of TSLP and TGF-β1 in the lung of the mice subjected to repeated allergen exposure, which was accompanied by increased number of fibrocytes in the sub-epithelial zone and the BAL fluid. However, blocking TSLP markedly decreased the production of TGF-β1, reduced the number of fibrocytes and subsequently prevented alterations of both airway and vascular structures. Conclusions: Our data suggested that TSLP might function in airway remodeling by promoting circulating fibrocyte recruitment to the lung in the mice subjected to chronic allergen exposure. These results provide a better rationale for targeting the interaction between TSLP and fibrocytes as a therapeutic approach for chronic allergic asthma.

[Influential factors for postpartum depression based on the structural equation model in Kaifu District in Changsha]

OBJECTIVE

To investigate the current status of the postpartum depression in Kaifu District in Changsha, and to explore the influential factors for postpartum depression.
 Methods: We selected the mothers, who had a delivery and met the inclusion criteria in Changsha during 2015, as the participants and established a prospective birth cohort study. The social demographic characteristics and health-related information for the mothers and their families were collected by using self-made questionnaire. The mothers' depression symptoms after one month postpartum were assessed by the Edinburgh Postnatal Depression Scale. We used the structural equation model to analyze the influential factors for postpartum depression.
 Results: A total of 961 cases were investigated. 82 of them whose scores of EPDS were≥9 points, and the incidence of PPD was 8.2%. The results of structural equation model revealed the influential factors and their correlations with postpartum depression. It has been shown that maternal age, maternal education level, per capita income of family, intention of pregnancy, pregnancy-related complications, mode of conception, mode of delivery, feeding patterns, birth weight, baby gender, and infant illness could exert effects on postpartum depression.
 Conclusion: The incidence of postpartum depression in Kaifu District is at a low level and the structural equation model can be applied to analyze the influential factors and their relations with postpartum depression.

TLR4 polymorphisms affect stroke risk and inflammatory response in Chinese ischemic stroke patients

This study aimed to evaluate the association of the toll-like receptor 4 (TLR4) polymorphisms rs1927914, rs10759932, and rs11536889 with susceptibility to ischemic stroke (IS) and the serum levels of inflammatory cytokines. A total of 816 IS patients and 816 control subjects were genotyped using Sequenom MassARRAY technology. The serum levels of interleukin 1 beta (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor alpha (TNFα) were measured by enzyme-linked immunosorbent assay. rs1927914 was significantly associated with male IS patients in the additive model [odds ratio (OR) = 0.81; 95% confidence interval (CI) = 0.67-0.99; P = 0.039] and in the allele model (OR = 0.81; 95% CI = 0.66-0.99; P = 0.037). In the dominant model, rs10759932 was significantly associated with the serum TNFα level of the male IS patients [regression coefficient (β) = 0.15; 95% CI = 0.01-0.29; P _adj = 0.042]. This polymorphism was also correlated with the serum IL-8 level of female IS patients in the additive model (β = 0.24; 95% CI = 0.25-0.43; P _adj = 0.021) and in the recessive model (β = 0.65; 95% CI = 0.11-1.11; P _adj = 0.026). The TLR4 gene rs1927914 polymorphism was associated with susceptibility to IS in males. Moreover, the rs10759932 polymorphism may affect inflammatory response in IS patients.

Characterization and expression analysis of a new small heat shock protein Hsp20.4 from Eimeria tenella

Small heat shock proteins (sHsps) are ubiquitous and diverse molecular chaperones. Found in almost all organisms, they regulate protein refolding and protect cells from stress. Until now, no sHsp has been characterized in Eimeria tenella. In this study, the novel EtsHsp20.4 gene was cloned from E. tenella by rapid amplification of cDNA ends based on a previously identified expressed sequence tag. The full-length cDNA was 1019bp in length and contained an open reading frame of 558bp that encoded a 185-amino acid polypeptide with a calculated molecular weight of 20.4 kDa. The EtsHsp20.4 protein contained a distinct HSP20/alpha-crystallin domain that is the key determinant of their function as molecular chaperones and belongs to the HSP20 protein family. EtsHsp20.4 mRNA levels were higher in sporulated oocysts than in sporozoites or second-generation merozoites by real-time quantitative PCR, the transcription of EtsHsp20.4 was barely detectable in unsporulated oocysts. Immunolocalization with EtsHsp20.4 antibody showed that EtsHsp20.4 was mainly located on the surface of sporozoites, first-generation merozoites and second-generation merozoites. Following the development of parasites in DF-1 cells, EtsHsp20.4 protein was uniformly dispersed in trophozoites, immature schizonts, and mature schizonts. Malate dehydrogenase thermal aggregation assays indicated that recombinant EtsHsp20.4 had molecular chaperone activity in vitro. These results suggested that EtsHsp20.4 might be involved in sporulation in external environments and intracellular growth of the parasite in the host.

Enhancing evidence-based diabetes and chronic disease control among local health departments: a multi-phase dissemination study with a stepped-wedge cluster randomized trial component

BACKGROUND

The rates of diabetes and prediabetes in the USA are growing, significantly impacting the quality and length of life of those diagnosed and financially burdening society. Premature death and disability can be prevented through implementation of evidence-based programs and policies (EBPPs). Local health departments (LHDs) are uniquely positioned to implement diabetes control EBPPs because of their knowledge of, and focus on, community-level needs, contexts, and resources. There is a significant gap, however, between known diabetes control EBPPs and actual diabetes control activities conducted by LHDs. The purpose of this study is to determine how best to support the use of evidence-based public health for diabetes (and related chronic diseases) control among local-level public health practitioners.

METHODS/DESIGN

This paper describes the methods for a two-phase study with a stepped-wedge cluster randomized trial that will evaluate dissemination strategies to increase the uptake of public health knowledge and EBPPs for diabetes control among LHDs. Phase 1 includes development of measures to assess practitioner views on and organizational supports for evidence-based public health, data collection using a national online survey of LHD chronic disease practitioners, and a needs assessment of factors influencing the uptake of diabetes control EBPPs among LHDs within one state in the USA. Phase 2 involves conducting a stepped-wedge cluster randomized trial to assess effectiveness of dissemination strategies with local-level practitioners at LHDs to enhance capacity and organizational support for evidence-based diabetes prevention and control. Twelve LHDs will be selected and randomly assigned to one of the three groups that cross over from usual practice to receive the intervention (dissemination) strategies at 8-month intervals; the intervention duration for groups ranges from 8 to 24 months. Intervention (dissemination) strategies may include multi-day in-person workshops, electronic information exchange methods, technical assistance through a knowledge broker, and organizational changes to support evidence-based public health approaches. Evaluation methods comprise surveys at baseline and the three crossover time points, abstraction of local-level diabetes and chronic disease control program plans and progress reports, and social network analysis to understand the relationships and contextual issues that influence EBPP adoption.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT03211832.

A Highly Sensitive Non-Radioactive Activity Assay for AMP-Activated Protein Kinase (AMPK)

While many methods exist to quantitatively determine protein kinase activities, ³²P-based radioactive assays remain the workhorse of many laboratories due to their high sensitivity, high signal to noise ratio, lack of interference by fluorescent and light-absorbing small molecules, and easy quantitation. Here, we demonstrate that the interaction between the yeast Rad53 Forkhead-associated (FHA) domain and a peptide optimized for phosphorylation by AMP-Activated Protein Kinase (AMPK), which has previously been exploited for the generation of intracellular phosphorylation sensors, can serve as a readout for a highly sensitive two-step AMPK AlphaScreen kinase assay with exceptional signal-to-noise ratio.

Estrogen deficiency is associated with hippocampal morphological remodeling of early postmenopausal mice

Estrogen (E₂) deficiency is reported to involve in the impairment of cognition in postmenopausal women. However, the morphological basis is still unclear. In the present study, using transmission electron microscopy (TEM), we observed the ultrastructure of hippocampus in female C57BL/6 mice at the age of 18 months (18 M) which is considered as the early stage of postmenopause (n = 8). Compared with control mice aged 6 M (n = 8), we identified that the morphological changes in the hippocampus of these menopausal mice were mitochondrial damage, lipofuscin deposition and microtubule degradation. Notably, after E₂ was subcutaneously injected into mice aged 16 M with a dosage of 3.5 μg/kg every three days for two months in the 18 M + E₂ group (n = 8), mitochondrial damage and lipofuscin deposition in the DG region of hippocampus were prevented, but the degraded microtubules in the hippocampus of postmenopausal mice were failed to restore. These data suggest that hippocampal ultrastructure remodeling in mice can be initiated at the early stage of postmenopause, E₂ supplementation could only have an effect on mitochondrial damage and lipofuscin increase.

Localized Surface Plasmon Resonance-Mediated Charge Trapping/Detrapping for Core-Shell Nanorod-Based Optical Memory Cells

For following the trend of miniaturization as per Moore's law, increasing efforts have been made to develop single devices with versatile functionalities for Internet of Things (IoT). In this work, organic optical memory devices with excellent dual optoelectronic functionality including light sensing and data storage have been proposed. The Au@Ag core-shell nanorods (NRs)-based memory device exhibits large memory window up to 19.7 V due to the well-controlled morphology of Au@Ag NRs with optimum size and concentration. Furthermore, since the extinction intensity of Au@Ag NRs gradually enhance with the increase in Ag shell thickness, the phototunable behaviors of memory device were systematically studied by varying the thickness of Ag shell. Multilevel data storage can be achieved with the light assistant. Finally, the simulation results demonstrate that the phototunable memory property is originated from the multimode localized surface plasmon resonance (LSPR) of Au@Ag NRs, which is in consistent with the experimental results. The Au@Ag core-shell NRs-based memories may open up a new strategy toward developing high-performance optoelectronic devices.

Associations of ambient coarse particulate matter, nitrogen dioxide, and carbon monoxide with the risk of kidney disease: a cohort study

BACKGROUND

Experimental evidence and preliminary clinical evidence suggest that environmental air pollution adversely effects kidney health. Previous work has examined the association between fine particulate matter and risk of kidney disease; however, the association between ambient coarse particulate matter (PM₁₀; ≤10 μm in aerodynamic diameter), nitrogen dioxide (NO₂), and carbon monoxide (CO) and risk of incident chronic kidney disease, chronic kidney disease progression, and end-stage renal disease is not clear.

METHODS

We merged multiple large databases, including those of the Environmental Protection Agency and the Department of Veterans Affairs, to build a cohort of US veterans, and used survival models to evaluate the association between PM₁₀, NO₂, and CO concentrations and risk of incident estimated glomerular filtration rate (eGFR) of less than 60 mL/min per 1·73 m², incident chronic kidney disease, eGFR decline of 30% or more, and end-stage renal disease. We treated exposure as time-varying when it was updated annually and as cohort participants moved.

FINDINGS

Between Oct 1, 2003, and Sept 30, 2012, 2 010 398 cohort participants were followed up over a median of 8·52 years (IQR 8·05-8·80). An increased risk of eGFR of less than 60 mL/min per 1·73 m² was associated with an IQR increase in concentrations of PM₁₀ (hazard ratio 1·07, 95% CI 1·06-1·08), NO₂ (1·09, 1·08-1·10), and CO (1·09, 1·08-1·10). An increased risk of incident chronic kidney disease was associated with an IQR increase in concentrations of PM₁₀ (1·07, 1·05-1·08), NO₂ (1·09, 1·08-1·11), and CO (1·10, 1·08-1·11). An increased risk of an eGFR decline of 30% or more was associated with an IQR increase in concentrations of PM₁₀ (1·08, 1·07-1·09), NO₂ (1·12, 1·10-1·13), and CO (1·09, 1·08-1·10). An increased risk of end-stage renal disease was associated with an IQR increase in concentrations of PM₁₀ (1·09, 1·06-1·12), NO₂ (1·09, 1·06-1·12), and CO (1·05, 1·02-1·08). Spline analyses suggested a monotonic increasing association between PM₁₀, NO₂, and CO concentrations and risk of kidney outcomes.

INTERPRETATION

Environmental exposure to higher concentrations of PM₁₀, NO₂, and CO is associated with increased risk of incident chronic kidney disease, eGFR decline, and end-stage renal disease.

FUNDING

US Department of Veterans Affairs.

Tunable insertion of multiple lines into a Kerr frequency comb using electro-optical modulators

We experimentally insert a flexible number of electro-optical (EO) comb lines into a Kerr frequency comb via EO modulation and demonstrate the use of combined Kerr and EO combs as light sources in coherent communications. The number of EO lines inserted into the Kerr comb can be varied by changing the modulation frequency. Additionally, the inserted EO comb is found to have similar coherence to that of the Kerr comb, as indicated by their linewidths. The high coherence of both the Kerr and EO combs has further been demonstrated in a communication experiment in which the comb lines are encoded with 10 Gbaud quadrature phase-shift-keyed signals. The increased number of comb lines after EO modulation indicates the possibility of obtaining more data channels in optical communications.

Mediators of Racial/Ethnic Disparities in Mentored K Award Receipt Among U.S. Medical School Graduates

PURPOSE

Mentored K (K01/K08/K23) career development awards are positively associated with physicians' success as independent investigators; however, individuals in some racial/ethnic groups are less likely to receive this federal funding. The authors sought to identify variables that explain (mediate) the association between race/ethnicity and mentored K award receipt among U.S. Liaison Committee for Medical Education-accredited medical school graduates who planned research-related careers.

METHOD

The authors analyzed deidentified data from the Association of American Medical Colleges and the National Institutes of Health Information for Management, Planning, Analysis, and Coordination II grants database for a national cohort of 28,690 graduates from 1997-2004 who planned research-related careers, followed through August 2014. The authors examined 10 potential mediators (4 research activities, 2 academic performance measures, medical school research intensity, degree program, debt, and specialty) of the association between race/ethnicity and mentored K award receipt in models comparing underrepresented minorities in medicine (URM) and non-URM graduates.

RESULTS

Among 27,521 graduates with complete data (95.9% of study-eligible graduates), 1,147 (4.2%) received mentored K awards (79/3,341 [2.4%] URM; 1,068/24,180 [4.4%] non-URM). All variables except debt were significant mediators; together they explained 96.2% (95%, CI 79.1%-100%) of the association between race/ethnicity and mentored K award.

CONCLUSIONS

Research-related activities during/after medical school and standardized academic measures largely explained the association between race/ethnicity and mentored K award in this national cohort. Interventions targeting these mediators could mitigate racial/ethnic disparities in the federally funded physician-scientist research workforce.

A method to induce human cortical long-term potentiation by acoustic stimulation

OBJECT

Acoustic stimulation induced LTP in the human auditory cortex was successfully recorded for the first time by electroencephalography (EEG) using a stimulus of 1 kHz pure-tone in 2005. However, it was barely reproduced, given considerable challenges to reliably elicit and accurately record the enhanced potentials in vivo. The purpose of this paper was to explore whether acoustic stimuli other than 1 kHz pure-tone could generate LTP or not.

MEASURES

To answer this question, we proposed a tetanic-stimulation paradigm of pure-tones, narrow-band noises (NBNs) and white noise (WN) to elicit LTP in human subjects.

RESULTS

The results showed that pure-tones with different frequency could elicit LTP in human auditory cortex, and proved for the first time that NBNs and WN could also achieve the same goal. Interestingly, it was also shown that the noises with certain bandwidth induced the greatest LTP and the WN induced LTP had the least variation over time and across subjects in comparison with pure-tones and NBNs.

CONCLUSIONS

In light of the results, we suggested to use the paradigm for broader studies of human in vivo cortical plasticity.

Defining the minimum substrate and charge recognition model of gamma-secretase

γ-Secretase is an intramembrane aspartyl protease that cleaves the C99 fragment of amyloid precursor protein to generate extracellular Aβ peptides. These peptides can oligomerize and aggregate to form amyloid plaques, processes that are widely believed to be causal for Alzheimer's disease. In spite of this critical function, it remains unknown how γ-secretase recognizes C99 and its other substrates, including Notch. In this study we determined E22-K55 as the minimal C99 fragment that was sufficient and required for initial cleavage. Within this fragment, we identified four determinants: (i) a transferable extracellular determinant that differed between C99 and Notch, and which included negative charge in the case of C99, (ii) the amino acid sequence of the C-terminal half of the transmembrane helix, (iii) an invariant lysine or arginine at the intracellular membrane border, and (iv) a positive charge cluster that included the invariant lysine/arginine. We demonstrated that the charge clusters of C99 and Notch receptors could directly bind phosphatidylinositol 4,5-bisphosphate (PIP2). The PIP2-binding cluster was required for γ-secretase cleavage, and modulation of membrane PIP2 levels strongly affected γ-secretase cleavage levels and the Aβ₄₀/Aβ₄₂ ratio, providing support for the importance of the PIP2 interaction in cells. Together, these studies provide critically needed insight into substrate recognition by γ-secretase.

Hermetic storage of wheat and maize flour protects against red flour beetle (Tribolium castaneum Herbst)

Hermetic storage is used to protect grain against insect pests, but its utility is not limited to whole grains. We evaluated hermetically-sealed, polyethylene terephthalate (PET) bottles for preserving wheat and maize flour against red flour beetle (RFB, Tribolium castaneum, Herbst) population growth. Flours infested with RFB and kept in sealed PET bottles experienced much less weight loss over a three-month storage period than infested flour kept in unsealed bottles. RFB populations in wheat flour kept in sealed bottles did not increase, while populations in unsealed bottles grew about 50-fold during the same three-month period. Flour in sealed bottles had lower levels of oxygen and moisture than flour stored in unsealed bottles. Similar trends were observed for oxygen and moisture levels in maize flour held in hermetically sealed bottles. Hermetically-sealed bottles were effective in preventing RFB population growth and preserving maize and wheat flour. Farmers, consumers and food processors can safely store grain flour in hermetic sealed containers.

Prognostic and clinical significance of VEGFR-3 in gastric cancer: A meta-analysis

BACKGROUND

Recent studies have suggested that VEGFR-3 is involved in the development of gastric cancer, however, the results are contradictory. Hence, we conducted a meta-analysis to assess the correlation between VEGFR-3 and the clinicopathological characteristics of gastric cancer to assess its prognostic value.

METHODS

An electronic search for relevant articles was conducted in PubMed, Cochrane Library, Web of Science, EMBASE database, and Chinese CNKI. Correlations between VEGFR-3 expression and clinicopathological features and survival outcomes were analyzed. Pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Positive VEGFR-3 expression was not correlated with gender or tumor differentiation. However, high levels of VEGFR-3 expression were significantly associated with depth of invasion and lymph node metastasis. Moreover, VEGFR-3 expression was associated with poor three year and five year overall survival rates (OS) in GC patients.

CONCLUSIONS

Our meta-analysis found that VEGFR-3 expression was associated with depth of invasion and lymph node metastasis in gastric cancer. The results suggest that VEGFR-3 may be a useful prognostic biomarker for gastric cancer.

Particulate Matter Air Pollution and the Risk of Incident CKD and Progression to ESRD

Elevated levels of fine particulate matter <2.5 µm in aerodynamic diameter (PM_2.5) are associated with increased risk of cardiovascular outcomes and death, but their association with risk of CKD and ESRD is unknown. We linked the Environmental Protection Agency and the Department of Veterans Affairs databases to build an observational cohort of 2,482,737 United States veterans, and used survival models to evaluate the association of PM_2.5 concentrations and risk of incident eGFR <60 ml/min per 1.73 m², incident CKD, eGFR decline ≥30%, and ESRD over a median follow-up of 8.52 years. County-level exposure was defined at baseline as the annual average PM_2.5 concentrations in 2004, and separately as time-varying where it was updated annually and as cohort participants moved. In analyses of baseline exposure (median, 11.8 [interquartile range, 10.1-13.7] µg/m³), a 10-µg/m³ increase in PM_2.5 concentration was associated with increased risk of eGFR<60 ml/min per 1.73 m² (hazard ratio [HR], 1.21; 95% confidence interval [95% CI], 1.14 to 1.29), CKD (HR, 1.27; 95% CI, 1.17 to 1.38), eGFR decline ≥30% (HR, 1.28; 95% CI, 1.18 to 1.39), and ESRD (HR, 1.26; 95% CI, 1.17 to 1.35). In time-varying analyses, a 10-µg/m³ increase in PM_2.5 concentration was associated with similarly increased risk of eGFR<60 ml/min per 1.73 m², CKD, eGFR decline ≥30%, and ESRD. Spline analyses showed a linear relationship between PM_2.5 concentrations and risk of kidney outcomes. Exposure estimates derived from National Aeronautics and Space Administration satellite data yielded consistent results. Our findings demonstrate a significant association between exposure to PM_2.5 and risk of incident CKD, eGFR decline, and ESRD.

Ezrin regulates skin fibroblast size/mechanical properties and YAP-dependent proliferation

Ezrin acts as a dynamic linkage between plasma membrane and cytoskeleton, and thus involved in many fundamental cellular functions. Yet, its potential role in human skin is virtually unknown. Here we investigate the role of Ezrin in primary skin fibroblasts, the major cells responsible extracellular matrix (ECM) production. We report that Ezrin play an important role in the maintenance of skin fibroblast size/mechanical properties and proliferation. siRNA-mediated Ezrin knockdown decreased fibroblast size and mechanical properties, and thus impaired the nuclear translocation of YAP, a protein commonly response to cell size and mechanical force. Functionally, depletion of Ezrin significantly inhibited YAP target gene expression and fibroblast proliferation. Conversely, restoration of YAP nuclear translocation by overexpression of constitutively active YAP reversed YAP target genes expression and rescued proliferation in Ezrin knockdown cells. These data reveal a novel role for Ezrin in maintenance of fibroblast size/mechanical force and regulating YAP-mediated proliferation.

[Clinical efficacy of clear aligners in treating bimaxillary protrusion]

Objective: To evaluate the efficiency of clear aligners in treating bimaxillary protrusion patients with first premolar extractions. Methods: Eleven patients with bimaxillary protrusion were selected in this study. All of them were treated by using clear aligners with four first premolar extractions and need maximal anchorage. Cephalometric analysis was carried out before and after treatment. Results: Cephalometric analysis results showed that significant changes in teeth and profile could be detected after clear aligner treatment and no change could be found in skeletal pattern. Upper and lower anterior teeth were retracted. The control of anterior torque and posterior anchorage were effective. The soft tissue analysis showed that position of upper and lower lip was significantly changed which improve the profile of patients. After treatment, the distance of U1 to NA and L1 to NB reduced by (5.19±4.12) mm and (4.53±1.20) mm, respectively. The differences were statistically significant (P<0.01). Conclusions: Bimaxillary protrusion patients who needed premolar extractions and maximal anchorage could be treated with clear aligners.

Amyloid beta: structure, biology and structure-based therapeutic development

Amyloid beta peptide (Aβ) is produced through the proteolytic processing of a transmembrane protein, amyloid precursor protein (APP), by β- and γ-secretases. Aβ accumulation in the brain is proposed to be an early toxic event in the pathogenesis of Alzheimer's disease, which is the most common form of dementia associated with plaques and tangles in the brain. Currently, it is unclear what the physiological and pathological forms of Aβ are and by what mechanism Aβ causes dementia. Moreover, there are no efficient drugs to stop or reverse the progression of Alzheimer's disease. In this paper, we review the structures, biological functions, and neurotoxicity role of Aβ. We also discuss the potential receptors that interact with Aβ and mediate Aβ intake, clearance, and metabolism. Additionally, we summarize the therapeutic developments and recent advances of different strategies for treating Alzheimer's disease. Finally, we will report on the progress in searching for novel, potentially effective agents as well as selected promising strategies for the treatment of Alzheimer's disease. These prospects include agents acting on Aβ, its receptors and tau protein, such as small molecules, vaccines and antibodies against Aβ; inhibitors or modulators of β- and γ-secretase; Aβ-degrading proteases; tau protein inhibitors and vaccines; amyloid dyes and microRNAs.