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Alzheimer's & Dementia : the Journal of... Apr 2018In 2011, the National Institute on Aging and Alzheimer's Association created separate diagnostic recommendations for the preclinical, mild cognitive impairment, and... (Review)
Review
In 2011, the National Institute on Aging and Alzheimer's Association created separate diagnostic recommendations for the preclinical, mild cognitive impairment, and dementia stages of Alzheimer's disease. Scientific progress in the interim led to an initiative by the National Institute on Aging and Alzheimer's Association to update and unify the 2011 guidelines. This unifying update is labeled a "research framework" because its intended use is for observational and interventional research, not routine clinical care. In the National Institute on Aging and Alzheimer's Association Research Framework, Alzheimer's disease (AD) is defined by its underlying pathologic processes that can be documented by postmortem examination or in vivo by biomarkers. The diagnosis is not based on the clinical consequences of the disease (i.e., symptoms/signs) in this research framework, which shifts the definition of AD in living people from a syndromal to a biological construct. The research framework focuses on the diagnosis of AD with biomarkers in living persons. Biomarkers are grouped into those of β amyloid deposition, pathologic tau, and neurodegeneration [AT(N)]. This ATN classification system groups different biomarkers (imaging and biofluids) by the pathologic process each measures. The AT(N) system is flexible in that new biomarkers can be added to the three existing AT(N) groups, and new biomarker groups beyond AT(N) can be added when they become available. We focus on AD as a continuum, and cognitive staging may be accomplished using continuous measures. However, we also outline two different categorical cognitive schemes for staging the severity of cognitive impairment: a scheme using three traditional syndromal categories and a six-stage numeric scheme. It is important to stress that this framework seeks to create a common language with which investigators can generate and test hypotheses about the interactions among different pathologic processes (denoted by biomarkers) and cognitive symptoms. We appreciate the concern that this biomarker-based research framework has the potential to be misused. Therefore, we emphasize, first, it is premature and inappropriate to use this research framework in general medical practice. Second, this research framework should not be used to restrict alternative approaches to hypothesis testing that do not use biomarkers. There will be situations where biomarkers are not available or requiring them would be counterproductive to the specific research goals (discussed in more detail later in the document). Thus, biomarker-based research should not be considered a template for all research into age-related cognitive impairment and dementia; rather, it should be applied when it is fit for the purpose of the specific research goals of a study. Importantly, this framework should be examined in diverse populations. Although it is possible that β-amyloid plaques and neurofibrillary tau deposits are not causal in AD pathogenesis, it is these abnormal protein deposits that define AD as a unique neurodegenerative disease among different disorders that can lead to dementia. We envision that defining AD as a biological construct will enable a more accurate characterization and understanding of the sequence of events that lead to cognitive impairment that is associated with AD, as well as the multifactorial etiology of dementia. This approach also will enable a more precise approach to interventional trials where specific pathways can be targeted in the disease process and in the appropriate people.
Topics: Alzheimer Disease; Animals; Biomarkers; Brain; Humans; National Institute on Aging (U.S.); United States
PubMed: 29653606
DOI: 10.1016/j.jalz.2018.02.018 -
Immunity Jul 2019Inflammation predisposes to the development of cancer and promotes all stages of tumorigenesis. Cancer cells, as well as surrounding stromal and inflammatory cells,... (Review)
Review
Inflammation predisposes to the development of cancer and promotes all stages of tumorigenesis. Cancer cells, as well as surrounding stromal and inflammatory cells, engage in well-orchestrated reciprocal interactions to form an inflammatory tumor microenvironment (TME). Cells within the TME are highly plastic, continuously changing their phenotypic and functional characteristics. Here, we review the origins of inflammation in tumors, and the mechanisms whereby inflammation drives tumor initiation, growth, progression, and metastasis. We discuss how tumor-promoting inflammation closely resembles inflammatory processes typically found during development, immunity, maintenance of tissue homeostasis, or tissue repair and illuminate the distinctions between tissue-protective and pro-tumorigenic inflammation, including spatiotemporal considerations. Defining the cornerstone rules of engagement governing molecular and cellular mechanisms of tumor-promoting inflammation will be essential for further development of anti-cancer therapies.
Topics: Animals; Autoimmunity; Carcinogenesis; Chronic Disease; Homeostasis; Humans; Infections; Inflammation; Neoplasms; Neovascularization, Pathologic; Tumor Microenvironment; Wound Healing
PubMed: 31315034
DOI: 10.1016/j.immuni.2019.06.025 -
Journal of Leukocyte Biology Aug 2019Macrophages play an important role in a wide variety of physiologic and pathologic processes. Plasticity and functional polarization are hallmarks of macrophages.... (Review)
Review
Macrophages play an important role in a wide variety of physiologic and pathologic processes. Plasticity and functional polarization are hallmarks of macrophages. Macrophages commonly exist in two distinct subsets: classically activated macrophages (M1) and alternatively activated macrophages (M2). M2b, a subtype of M2 macrophages, has attracted increasing attention over the past decade due to its strong immune-regulated and anti-inflammatory effects. A wide variety of stimuli and multiple factors modulate M2b macrophage polarization in vitro and in vivo. M2b macrophages possess both protective and pathogenic roles in various diseases. Understanding the mechanisms of M2b macrophage activation and the modulation of their polarization might provide a great perspective for the design of novel therapeutic strategies. The purpose of this review is to discuss current knowledge of M2b macrophage polarization, the roles of M2b macrophages in a variety of diseases and the stimuli to modulate M2b macrophage polarization.
Topics: Animals; Biomarkers; Disease Susceptibility; Gene Expression Regulation; Humans; Immunomodulation; Immunophenotyping; Macrophage Activation; Macrophages; Phenotype; Signal Transduction
PubMed: 30576000
DOI: 10.1002/JLB.3RU1018-378RR -
Angiogenesis Aug 2023In multicellular organisms, angiogenesis, the formation of new blood vessels from pre-existing ones, is an essential process for growth and development. Different... (Review)
Review
In multicellular organisms, angiogenesis, the formation of new blood vessels from pre-existing ones, is an essential process for growth and development. Different mechanisms such as vasculogenesis, sprouting, intussusceptive, and coalescent angiogenesis, as well as vessel co-option, vasculogenic mimicry and lymphangiogenesis, underlie the formation of new vasculature. In many pathological conditions, such as cancer, atherosclerosis, arthritis, psoriasis, endometriosis, obesity and SARS-CoV-2(COVID-19), developmental angiogenic processes are recapitulated, but are often done so without the normal feedback mechanisms that regulate the ordinary spatial and temporal patterns of blood vessel formation. Thus, pathological angiogenesis presents new challenges yet new opportunities for the design of vascular-directed therapies. Here, we provide an overview of recent insights into blood vessel development and highlight novel therapeutic strategies that promote or inhibit the process of angiogenesis to stabilize, reverse, or even halt disease progression. In our review, we will also explore several additional aspects (the angiogenic switch, hypoxia, angiocrine signals, endothelial plasticity, vessel normalization, and endothelial cell anergy) that operate in parallel to canonical angiogenesis mechanisms and speculate how these processes may also be targeted with anti-angiogenic or vascular-directed therapies.
Topics: Female; Humans; COVID-19; SARS-CoV-2; Neovascularization, Pathologic; Neoplasms; Endothelial Cells; Angiogenesis Inhibitors
PubMed: 37060495
DOI: 10.1007/s10456-023-09876-7 -
Cellular and Molecular Life Sciences :... May 2020Tumor vascularization occurs through several distinct biological processes, which not only vary between tumor type and anatomic location, but also occur simultaneously... (Review)
Review
Tumor vascularization occurs through several distinct biological processes, which not only vary between tumor type and anatomic location, but also occur simultaneously within the same cancer tissue. These processes are orchestrated by a range of secreted factors and signaling pathways and can involve participation of non-endothelial cells, such as progenitors or cancer stem cells. Anti-angiogenic therapies using either antibodies or tyrosine kinase inhibitors have been approved to treat several types of cancer. However, the benefit of treatment has so far been modest, some patients not responding at all and others acquiring resistance. It is becoming increasingly clear that blocking tumors from accessing the circulation is not an easy task to accomplish. Tumor vessel functionality and gene expression often differ vastly when comparing different cancer subtypes, and vessel phenotype can be markedly heterogeneous within a single tumor. Here, we summarize the current understanding of cellular and molecular mechanisms involved in tumor angiogenesis and discuss challenges and opportunities associated with vascular targeting.
Topics: Angiogenesis Inhibitors; Animals; Humans; Neoplasms; Neovascularization, Pathologic; Signal Transduction
PubMed: 31690961
DOI: 10.1007/s00018-019-03351-7 -
Science (New York, N.Y.) Aug 2014Preterm birth is associated with 5 to 18% of pregnancies and is a leading cause of infant morbidity and mortality. Spontaneous preterm labor, a syndrome caused by... (Review)
Review
Preterm birth is associated with 5 to 18% of pregnancies and is a leading cause of infant morbidity and mortality. Spontaneous preterm labor, a syndrome caused by multiple pathologic processes, leads to 70% of preterm births. The prevention and the treatment of preterm labor have been long-standing challenges. We summarize the current understanding of the mechanisms of disease implicated in this condition and review advances relevant to intra-amniotic infection, decidual senescence, and breakdown of maternal-fetal tolerance. The success of progestogen treatment to prevent preterm birth in a subset of patients at risk is a cause for optimism. Solving the mystery of preterm labor, which compromises the health of future generations, is a formidable scientific challenge worthy of investment.
Topics: Decidua; Female; Fetus; Humans; Immune Tolerance; Infections; Inflammation; Obstetric Labor, Premature; Placenta; Pregnancy; Syndrome; Vascular Diseases
PubMed: 25124429
DOI: 10.1126/science.1251816 -
Parkinsonism & Related Disorders Jan 2018Parkinson's disease (PD) is characterized by bradykinesia, rigidity, postural instability and tremor. Several pathologic processes can produce this syndrome, but... (Review)
Review
INTRODUCTION
Parkinson's disease (PD) is characterized by bradykinesia, rigidity, postural instability and tremor. Several pathologic processes can produce this syndrome, but neurodegeneration accompanied by neuronal inclusions composed of α-synuclein (Lewy bodies) is considered the typical pathologic correlate of PD.
METHODS
The neuropathologic features of PD are reviewed based upon personal experience and review of the literature. Molecular pathology of PD is summarized from cell biological and animal studies.
RESULTS
The pathologic feature that correlates with signs and symptoms of PD is neuronal loss in the substantia nigra with dopaminergic denervation of the striatum. Neuronal degeneration in the substantia nigra preferentially affects the ventrolateral cell group that projects to posterolateral putamen and is accompanied by formation of Lewy bodies composed of aggregated α-synuclein. Some patients with PD are found at autopsy to have other pathologic processes, such as multiple system atrophy, progressive supranuclear palsy and cerebrovascular disease (vascular Parkinsonism). The peripheral autonomic nervous system is also affected. The triggering event in PD is unknown, but recent studies suggest a role for loss of nuclear membrane integrity. Once α-synuclein aggregates forms, evidence supports cell-to-cell propagation.
CONCLUSION
PD is a multisystem synucleinopathy caused by poorly characterized genetic and environmental factors that produces degeneration in selectively vulnerable neuronal populations.
Topics: Brain; Humans; Neuropathology; Parkinson Disease
PubMed: 28780180
DOI: 10.1016/j.parkreldis.2017.07.033 -
Romanian Journal of Morphology and... 2018Vascular endothelial growth factor (VEGF) represents a growth factor with important pro-angiogenic activity, having a mitogenic and an anti-apoptotic effect on... (Review)
Review
Vascular endothelial growth factor (VEGF) represents a growth factor with important pro-angiogenic activity, having a mitogenic and an anti-apoptotic effect on endothelial cells, increasing the vascular permeability, promoting cell migration, etc. Due to these effects, it actively contributes in regulating the normal and pathological angiogenic processes. In humans, the VEGF family is composed of several members: VEGF-A (which has different isoforms), VEGF-B, VEGF-C, VEGF-D, VEGF-E (viral VEGF), VEGF-F (snake venom VEGF), placenta growth factor (PlGF), and, recently, to this family has been added endocrine gland-derived vascular endothelial growth factor (EG-VEGF). VEGF binds to tyrosine kinase cell receptors (VEGFRs): VEGFR-1 [Fms-like tyrosine kinase 1 (Flt-1)], VEGFR-2 [kinase insert domain receptor (KDR) in human; fetal liver kinase 1 (Flk-1) in mouse] and VEGFR-3 [Fms-like tyrosine kinase 4 (Flt-4)]. While VEGFR-1 and VEGFR-2 are expressed predominantly on vascular endothelial cells, VEGFR-3 is expressed especially on lymphatic endothelial cells. VEGFR-2 has the strongest pro-angiogenic activity and a higher tyrosine kinase activity than VEGFR-1. Endothelial cells also express co-receptors, such as neuropilin-1 (NP-1) and neuropilin-2 (NP-2), which modulate tyrosine kinase receptor activity. Both VEGF and VEGFRs are expressed not only on endothelial cells, but also on non-endothelial cells. This article aims to highlight the most recent data referring to the VEGF family and its receptors, as well as its implications in the angiogenesis process. At present, blocking angiogenesis in cancer or in other pathological processes, using anti-VEGF and anti-VEGFRs therapies, is considered to be extremely important.
Topics: Angiogenesis Inhibitors; Animals; Humans; Neoplasms; Neovascularization, Pathologic; Vascular Endothelial Growth Factor A
PubMed: 30173249
DOI: No ID Found -
Journal of the American Heart... Aug 2023Cardiogenic shock is characterized by tissue hypoxia caused by circulatory failure arising from inadequate cardiac output. In addition to treating the pathologic process... (Review)
Review
Cardiogenic shock is characterized by tissue hypoxia caused by circulatory failure arising from inadequate cardiac output. In addition to treating the pathologic process causing impaired cardiac function, prompt hemodynamic support is essential to reduce the risk of developing multiorgan dysfunction and to preserve cellular metabolism. Pharmacologic therapy with the use of vasopressors and inotropes is a key component of this treatment strategy, improving perfusion by increasing cardiac output, altering systemic vascular resistance, or both, while allowing time and hemodynamic stability to treat the underlying disease process implicated in the development of cardiogenic shock. Despite the use of mechanical circulatory support recently garnering significant interest, pharmacologic hemodynamic support remains a cornerstone of cardiogenic shock management, with over 90% of patients receiving at least 1 vasoactive agent. This review aims to describe the pharmacology and hemodynamic effects of current pharmacotherapies and provide a practical approach to their use, while highlighting important future research directions.
Topics: Humans; Shock, Cardiogenic; Vasoconstrictor Agents; Hemodynamics; Vascular Resistance; Perfusion
PubMed: 37489740
DOI: 10.1161/JAHA.123.029787 -
Progress in Retinal and Eye Research Sep 2021Five vascular endothelial growth factor receptor (VEGFR) ligands (VEGF-A, -B, -C, -D, and placental growth factor [PlGF]) constitute the VEGF family. VEGF-A binds VEGF... (Review)
Review
Five vascular endothelial growth factor receptor (VEGFR) ligands (VEGF-A, -B, -C, -D, and placental growth factor [PlGF]) constitute the VEGF family. VEGF-A binds VEGF receptors 1 and 2 (VEGFR1/2), whereas VEGF-B and PlGF only bind VEGFR1. Although much research has been conducted on VEGFR2 to elucidate its key role in retinal diseases, recent efforts have shown the importance and involvement of VEGFR1 and its family of ligands in angiogenesis, vascular permeability, and microinflammatory cascades within the retina. Expression of VEGFR1 depends on the microenvironment, is differentially regulated under hypoxic and inflammatory conditions, and it has been detected in retinal and choroidal endothelial cells, pericytes, retinal and choroidal mononuclear phagocytes (including microglia), Müller cells, photoreceptor cells, and the retinal pigment epithelium. Whilst the VEGF-A decoy function of VEGFR1 is well established, consequences of its direct signaling are less clear. VEGFR1 activation can affect vascular permeability and induce macrophage and microglia production of proinflammatory and proangiogenic mediators. However the ability of the VEGFR1 ligands (VEGF-A, PlGF, and VEGF-B) to compete against each other for receptor binding and to heterodimerize complicates our understanding of the relative contribution of VEGFR1 signaling alone toward the pathologic processes seen in diabetic retinopathy, retinal vascular occlusions, retinopathy of prematurity, and age-related macular degeneration. Clinically, anti-VEGF drugs have proven transformational in these pathologies and their impact on modulation of VEGFR1 signaling is still an opportunity-rich field for further research.
Topics: Endothelial Cells; Humans; Inflammation; Neovascularization, Pathologic; Placenta Growth Factor; Retina; Signal Transduction; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1
PubMed: 33640465
DOI: 10.1016/j.preteyeres.2021.100954