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Li C, Stebbins RC, Noppert GA, Carney CX, Liu C, Sapp ARM, Watson EJ, Aiello AE. Peripheral immune function and Alzheimer's disease: a living systematic review and critical appraisal. Mol Psychiatry 2024; 29:1895-1905. [PMID: 38102484 DOI: 10.1038/s41380-023-02355-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/21/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023]
Abstract
BACKGROUND A growing body of literature examines the relationship between peripheral immune function and Alzheimer's Disease (AD) in human populations. Our living systematic review summarizes the characteristics and findings of these studies, appraises their quality, and formulates recommendations for future research. METHODS We searched the electronic databases PubMed, PsycINFO, and Web of Science, and reviewed references of previous reviews and meta-analyses to identify human studies examining the relationship between any peripheral immune biomarkers and AD up to September 7th, 2023. We examined patterns of reported statistical associations (positive, negative, and null) between each biomarker and AD across studies. Evidence for each biomarker was categorized into four groups based on the proportion of studies reporting different associations: corroborating a positive association with AD, a negative association, a null association, and presenting contradictory findings. A modified Newcastle-Ottawa scale (NOS) was employed to assess the quality of the included studies. FINDINGS In total, 286 studies were included in this review. The majority were cross-sectional (n = 245, 85.7%) and hospital-based (n = 248, 86.7%), examining relationships between 187 different peripheral immune biomarkers and AD. Cytokines were the most frequently studied group of peripheral immune biomarkers. Evidence supported a positive association with AD for six biomarkers, including IL-6, IL-1β, IFN-γ, ACT, IL-18, and IL-12, and a negative association for two biomarkers, including lymphocytes and IL-6R. Only a small proportion of included studies (n = 22, 7.7%) were deemed to be of high quality based on quality assessment. INTERPRETATION Existing research on peripheral immune function and AD exhibits substantial methodological variations and limitations, with a notable lack of longitudinal, population-based studies investigating a broad range of biomarkers with prospective AD outcomes. The extent and manner in which peripheral immune function can contribute to AD pathophysiology remain open questions. Given the biomarkers that we identified to be associated with AD, we posit that targeting peripheral immune dysregulation may present a promising intervention point to reduce the burden of AD.
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Affiliation(s)
- Chihua Li
- Social Environment and Health Program, Institute for Social Research, University of Michigan, Ann Arbor, MI, USA.
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA.
- Department of Epidemiology, School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
| | - Rebecca C Stebbins
- Robert N. Butler Columbia Aging Center, Mailman School of Public Health, Columbia University, New York City, NY, USA
| | - Grace A Noppert
- Social Environment and Health Program, Institute for Social Research, University of Michigan, Ann Arbor, MI, USA
| | - Constanza X Carney
- Department of Epidemiology, Milken Institute School of Public Health, The George Washington University, Washington, DC, USA
| | - Chunyu Liu
- Department of Mental Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Ashley R M Sapp
- Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Elijah J Watson
- Department of Anthropology, Northwestern University, Evanston, IL, USA
| | - Allison E Aiello
- Robert N. Butler Columbia Aging Center, Mailman School of Public Health, Columbia University, New York City, NY, USA
- Department of Epidemiology, Mailman School of Public, Columbia University, New York City, NY, USA
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Age-Related Male Hypogonadism and Cognitive Impairment in the Elderly: Focus on the Effects of Testosterone Replacement Therapy on Cognition. Geriatrics (Basel) 2020; 5:geriatrics5040076. [PMID: 33081371 PMCID: PMC7709679 DOI: 10.3390/geriatrics5040076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/09/2020] [Accepted: 10/13/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Epidemiological data report that male hypogonadism may play a role in cognitive impairment in elderly. However, the effect of testosterone replacement therapy (TRT) on cognitive abilities in this cluster of patients has not been well established. Methods. PubMed/MEDLINE, Google Scholar, Cochrane Library, and Web of Science were searched by using free text words and medical subject headings terms related with "male hypogonadism", "late-onset hypogonadism", elderly, cognition, "mild cognitive impairment", memory, "testosterone replacement therapy" used in various combinations according to the specific clinical questions. Original articles, reviews, and randomized controlled trials written in English were selected. Results. A long-term TRT could improve specific cognitive functions, such as verbal and spatial memory, cognitive flexibility, and physical vitality. However, randomized controlled trials do not provide positive results, and in most of the cases TRT might not induce beneficial effects on cognitive function in elderly men. Discussion and conclusions. Since the lengthening of life expectancy, the prevalence rate of cognitive decline in elderly men is expected to increase remarkably over the next decade with considerable healthcare and economical concerns. Therefore, this remains a relevant clinical topic and further investigations are needed for clarifying the role of TRT especially in elderly men with hypogonadism.
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West NA, Kullo IJ, Morris MC, Mosley TH. Sex-specific associations of inflammation markers with cognitive decline. Exp Gerontol 2020; 138:110986. [PMID: 32497552 DOI: 10.1016/j.exger.2020.110986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/16/2020] [Accepted: 05/26/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND/OBJECTIVE Inflammation is implicated in cognitive decline; however, there is a paucity of data for African American populations and for sex-specific associations. DESIGN Prospective cohort study. SETTING Genetic Epidemiology Network of Arteriopathy/Genetics of Microangiopathic Brain Injury studies. PARTICIPANTS African-American sibships (N = 1010). MEASUREMENTS Neurocognitive tests assessed global cognition and four cognitive domains: processing speed, memory, language, and executive function at two time points over seven years. Circulating levels of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor receptor (TNFR)-1 and TNFR2 were measured at study baseline. Linear mixed models were used to investigate the association between inflammation markers and cognitive decline. RESULTS Among men, a one SD increase in CRP was associated with an increased rate of decline over 7 years in global cognitive Z-score (adjusted difference in slopes = -0.31, p = 0.006) and in processing speed Z-score (adjusted difference in slopes = -0.10, p = 0.02), but not declines in memory, language, or executive function Z-scores. Also among men, a one SD increase in IL-6 was associated with an increased decline rate in global cognitive Z-score (adjusted difference in slopes = -0.33, p = 0.002) and in processing speed Z-score (adjusted difference in slopes = -0.12, p = 0.007). There was no difference in decline rates by CRP or IL-6 level in adjusted analyses among women for any cognitive scores. Among men and women combined, a one SD increase in baseline sTNFR1 was associated with a faster rate of decline in memory Z-score (adjusted difference in slopes = -0.09, p = 0.02). Baseline sTNFR2 levels did not significantly predict rate of cognitive decline in any cognitive domains. CONCLUSIONS Circulating markers of CRP and IL-6 may be differential risk factors for men and women in relation to cognitive decline. A novel inflammation marker, sTNFR1, may be a useful predictor of memory decline in older adults.
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Affiliation(s)
- Nancy A West
- Department of Internal Medicine, Division of Epidemiology, University of Utah, Salt Lake City, UT, United States of America.
| | - Iftikhar J Kullo
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - M Caroline Morris
- School of Medicine, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Thomas H Mosley
- Department of Medicine, Division of Geriatrics, University of Mississippi Medical Center, Jackson, MS, United States of America
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Smith KF, Quinn RL, Rahilly LJ. Biomarkers for differentiation of causes of respiratory distress in dogs and cats: Part 2--Lower airway, thromboembolic, and inflammatory diseases. J Vet Emerg Crit Care (San Antonio) 2016; 25:330-48. [PMID: 26040815 DOI: 10.1111/vec.12317] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 03/22/2015] [Indexed: 01/08/2023]
Abstract
OBJECTIVES To review the current veterinary and relevant human literature regarding biomarkers of respiratory diseases leading to dyspnea and to summarize the availability, feasibility, and practicality of using respiratory biomarkers in the veterinary setting. DATA SOURCES Veterinary and human medical literature: original research articles, scientific reviews, consensus statements, and recent textbooks. HUMAN DATA SYNTHESIS Numerous biomarkers have been evaluated in people for discriminating respiratory disease processes with varying degrees of success. VETERINARY DATA SYNTHESIS Although biomarkers should not dictate clinical decisions in lieu of gold standard diagnostics, their use may be useful in directing care in the stabilization process. Serum immunoglobulins have shown promise as an indicator of asthma in cats. A group of biomarkers has also been evaluated in exhaled breath. Of these, hydrogen peroxide has shown the most potential as a marker of inflammation in asthma and potentially aspiration pneumonia, but methods for measurement are not standardized. D-dimers may be useful in screening for thromboembolic disease in dogs. There are a variety of markers of inflammation and oxidative stress, which are being evaluated for their ability to assess the severity and type of underlying disease process. Of these, amino terminal pro-C-type natriuretic peptide may be the most useful in determining if antibiotic therapy is warranted. Although critically evaluated for their use in respiratory disorders, many of the biomarkers which have been evaluated have been found to be affected by more than one type of respiratory or systemic disease. CONCLUSION At this time, there are point-of-care biomarkers that have been shown to reliably differentiate between causes of dyspnea in dogs and cats. Future clinical research is warranted to understand of how various diseases affect the biomarkers and more bedside tests for their utilization.
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Koks N, Ghassabian A, Greaves-Lord K, Hofman A, Jaddoe VW, Verhulst FC, Tiemeier H. Maternal C-Reactive Protein Concentration in Early Pregnancy and Child Autistic Traits in the General Population. Paediatr Perinat Epidemiol 2016; 30:181-9. [PMID: 26860445 PMCID: PMC4751036 DOI: 10.1111/ppe.12261] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Exposure to elevated levels of inflammatory markers during pregnancy has been suggested as possible aetiologic factor in the occurrence of autism spectrum disorder (ASD). In this study, we investigated the prospective relation between maternal C-reactive protein (CRP) during early pregnancy and children's autistic traits in the general population. METHODS In a large population-based cohort in the Netherlands, we measured maternal CRP levels before 18 weeks of gestation (N = 4165). Parents reported on their children's autistic traits at age 6 years using the Social Responsiveness Scale, and the Pervasive Developmental Problem scale. Regression models were used to examine the relation between maternal CRP levels and autistic traits in children. RESULTS Compared with the reference group (CRP < 2.3 mg/L), elevated levels of CRP (>7.8 mg/L) in pregnant women were associated with higher Social Responsiveness Scale scores in children [β = 0.055, 95% confidence interval (CI) 0.033, 0.078]; however, the effect was strongly attenuated after adjustment for several socioeconomic factors and in particular by maternal health-related factors including body mass index (fully adjusted model β = 0.018, 95% CI -0.005, 0.042). We found no relation between maternal CRP levels and pervasive developmental problem. CONCLUSIONS Our results suggest that the association between elevated levels of maternal CRP in pregnancy and autistic traits in children is confounded by maternal health-related and socioeconomic factors. Further studies are needed to explore whether other maternal inflammatory markers during pregnancy, as a response to maternal inflammation, are associated with the development of autistic traits in the offspring.
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Affiliation(s)
- Natasja Koks
- The Generation R Study Group, Erasmus University Medical Center, 3000 CB Rotterdam, the Netherlands.,Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center-Sophia Children's Hospital, 3000 CB Rotterdam, the Netherlands
| | - Akhgar Ghassabian
- The Generation R Study Group, Erasmus University Medical Center, 3000 CB Rotterdam, the Netherlands.,Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center-Sophia Children's Hospital, 3000 CB Rotterdam, the Netherlands.,Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA
| | - Kirstin Greaves-Lord
- Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center-Sophia Children's Hospital, 3000 CB Rotterdam, the Netherlands.,Yulius Academy, Yulius, Organization of Mental Health, Dordrecht, The Netherlands
| | - Albert Hofman
- Department of Epidemiology, Erasmus University Medical Center, 3000 CB Rotterdam, the Netherlands
| | - Vincent W.V. Jaddoe
- The Generation R Study Group, Erasmus University Medical Center, 3000 CB Rotterdam, the Netherlands.,Department of Epidemiology, Erasmus University Medical Center, 3000 CB Rotterdam, the Netherlands.,Department of Pediatrics, Erasmus University Medical Center-Sophia Children's Hospital, 3000 CB Rotterdam, the Netherlands
| | - Frank C. Verhulst
- Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center-Sophia Children's Hospital, 3000 CB Rotterdam, the Netherlands
| | - Henning Tiemeier
- Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center-Sophia Children's Hospital, 3000 CB Rotterdam, the Netherlands.,Department of Epidemiology, Erasmus University Medical Center, 3000 CB Rotterdam, the Netherlands.,Department of Psychiatry, Erasmus University Medical Center, 3000 CB Rotterdam, the Netherlands
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Heringa SM, van den Berg E, Reijmer YD, Nijpels G, Stehouwer CDA, Schalkwijk CG, Teerlink T, Scheffer PG, van den Hurk K, Kappelle LJ, Dekker JM, Biessels GJ. Markers of low-grade inflammation and endothelial dysfunction are related to reduced information processing speed and executive functioning in an older population - the Hoorn Study. Psychoneuroendocrinology 2014; 40:108-18. [PMID: 24485482 DOI: 10.1016/j.psyneuen.2013.11.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/26/2013] [Accepted: 11/11/2013] [Indexed: 11/29/2022]
Abstract
Low-grade inflammation and endothelial dysfunction are related to cognitive decline and dementia, in a complex interplay with vascular factors and aging. We investigated, in an older population, low-grade inflammation and endothelial dysfunction in relation to detailed assessment of cognitive functioning. Furthermore, we explored this association within the context of vascular factors. 377 participants (73 ± 6 years) of the population-based Hoorn Study were included. In plasma samples of 2000-2001 (n=363) and/or 2005-2008 (n=323), biomarkers were determined of low-grade inflammation (CRP, TNF-alpha, IL-6, IL-8, SAA, MPO, and sICAM-1) and endothelial dysfunction (vWF, sICAM-1, sVCAM-1, sTM, sE-selectin). In 2005-2008, all participants underwent neuropsychological examination. Composite z-scores were computed for low-grade inflammation and endothelial dysfunction at both time points, and for six domains of cognitive functioning (abstract reasoning, memory, information processing speed, attention and executive functioning, visuoconstruction, and language). The association between low-grade inflammation and endothelial dysfunction, and cognitive functioning was evaluated with linear regression analysis. In secondary analyses, we explored the relation with vascular risk factors and cardiovascular disease. Low-grade inflammation and endothelial dysfunction were associated with worse performance on information processing speed and attention and executive functioning, in prospective and cross-sectional analyses (standardized betas ranging from -0.20 to -0.10). No significant relation with other cognitive domains was observed. Adjusting for vascular factors slightly attenuated the associations. Low-grade inflammation and endothelial dysfunction accounted for only 2.6% explained variance in cognitive functioning, on top of related vascular risk factors and cardiovascular disease. Bootstrapping analyses show that low-grade inflammation and endothelial dysfunction mediate the relation between vascular risk factors and cognitive functioning. This study shows that low-grade inflammation and endothelial dysfunction contribute to reduced information processing speed and executive functioning in an older population.
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Affiliation(s)
- S M Heringa
- University Medical Center Utrecht, Brain Center Rudolf Magnus, Department of Neurology, Utrecht, The Netherlands.
| | - E van den Berg
- University Medical Center Utrecht, Brain Center Rudolf Magnus, Department of Neurology, Utrecht, The Netherlands; Utrecht University, Helmholtz Institute, Department of Experimental Psychology, Utrecht, The Netherlands
| | - Y D Reijmer
- Massachusetts General Hospital, J. Philip Kistler Stroke Research Center, Boston, United States
| | - G Nijpels
- VU University Medical Center, Institute for Research in Extramural Medicine (EMGO Institute), Amsterdam, The Netherlands; VU University Medical Center, Department of General Practice, Amsterdam, The Netherlands
| | - C D A Stehouwer
- Maastricht University Medical Centre, Department of Internal Medicine, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, Maastricht, The Netherlands
| | - C G Schalkwijk
- Maastricht University Medical Centre, Department of Internal Medicine, Maastricht, The Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, Maastricht, The Netherlands
| | - T Teerlink
- VU University Medical Center, Department of Clinical Chemistry, Amsterdam, The Netherlands
| | - P G Scheffer
- VU University Medical Center, Department of Clinical Chemistry, Amsterdam, The Netherlands
| | - K van den Hurk
- Sanquin Blood Supply, Department of Donor Studies, Amsterdam, The Netherlands
| | - L J Kappelle
- University Medical Center Utrecht, Brain Center Rudolf Magnus, Department of Neurology, Utrecht, The Netherlands
| | - J M Dekker
- VU University Medical Center, Institute for Research in Extramural Medicine (EMGO Institute), Amsterdam, The Netherlands
| | - G J Biessels
- University Medical Center Utrecht, Brain Center Rudolf Magnus, Department of Neurology, Utrecht, The Netherlands
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C-reactive protein and cognition are unrelated to leukoaraiosis. ScientificWorldJournal 2014; 2014:121679. [PMID: 24587705 PMCID: PMC3919109 DOI: 10.1155/2014/121679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 10/21/2013] [Indexed: 11/23/2022] Open
Abstract
Elevated serum levels of C-reactive protein (CRP) have been associated with leukoaraiosis in elderly brain. However, several studies indicate that leukoaraiosis is associated with an increased risk of cognitive impairment. It is unknown how the effect of CRP on cognition is mediated by leukoaraiosis. The purpose of this study is to assess the relationship between serum levels of CRP, the presence of leukoaraiosis, and cognitive impairment in a population of coronary patients over 50 years old. CRP levels explained 7.18% (P: 0.002) of the variance of the MMSE. The adjustment for the presence of leukoaraiosis little changed this variance (5.98%, P: 0.005), indicating that only a small portion of the CRP influence on cognition was mediated via leukoaraiosis. Patients with CRP levels ≥5.0 had 2.9 (95% CI: 1.26–6.44) times more chance to present cognitive impairment (P: 0.012). We found that elevated serum levels of CRP were associated with increased risk of cognitive impairment in elderly and it was not mediated by presence of leukoaraiosis.
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