VEEV TC-83 Triggers Dysregulation of the Tryptophan–Kynurenine Pathway in the Central Nervous System That Correlates with Cognitive Impairment in Tg2576 Mice

May combine two claims.

Dysregulation of these enzymes and metabolites is implicated in neurodegenerative disorders and found to be elevated in the blood and CSF of AD patients.

“The dysregulation of these enzymes and metabolites is implicated in neurodegenerative disorders and found to be elevated in the blood and CSF of AD patients [27].”

• cites [27] Gonzalez-Sanchez, M., Jimenez, J., Narvaez, A., Antequera, D., Llamas-Velasco, S., Martin, A.H., Arjona, J.A.M., Munain, A.L., Bisa, A.L., and Marco, M.P. (2020). Kynurenic Acid Levels are Increased in the CSF of Alzheimer’s Disease Patients. Biomolecules, 10. sourceDisputed

  Results §3.2 reports elevated kynurenic acid (KYNA) in the CSF of AD patients, but §3.3 directly contradicts the claim that it was also elevated in blood: plasma KYNA and TRP showed no significant change versus controls. The paper discusses elevated pathway enzymes in AD brains, not elevated enzymes in patients’ blood and CSF. Page numbers are unavailable in our copy. (LLM, conf=0.88)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

QUIN is transiently produced and metabolized into NAD+ in response to inflammation and infection.

“Furthermore, QUIN is transiently produced and metabolized into NAD+ in response to inflammation and infection [59,60].”

• cites [59] Grant, 2018, Indoleamine 2,3-Dioxygenase Activity Increases NAD+ Production in IFN-gamma-Stimulated Human Primary Mononuclear Cells, Int. J. Tryptophan Res. sourcePartly supported

  The Results section (page unavailable) reports increased QUIN after 48 hours of IFN-γ stimulation in human monocytes and macrophages. The Discussion identifies QUIN as an NAD precursor, but the paper does not establish that its production is transient or show this response during infection. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [60] Minhas, 2019, Macrophage de novo NAD(+) synthesis specifies immune function in aging and inflammation, Nat. Immunol. sourceDisputed

  The Results (no page number available) show that LPS challenge increased quinolinic acid (QA), but reduced QPRT expression and the NAD+ precursors downstream of QA. The Discussion explicitly says immune challenge impeded conversion of QA to NAD+, contrary to the claim that this conversion occurs in response to inflammation. The cited passages do not establish that QA production is transient. (LLM, conf=0.84)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

VEEV is a mosquito-borne alphavirus that causes a highly virulent central nervous system disease in horses and other equines with spill-over infections in humans.

“Venezuelan equine encephalitis virus (VEEV) is a mosquito-borne alphavirus that causes a highly virulent central nervous system (CNS) disease in horses and other equines with spill-over infections in humans [3,4].”

• cites [3] Aguilar, 2011, Endemic Venezuelan equine encephalitis in the Americas: Hidden under the dengue umbrella, Future Virol. sourcePartly supported

  The Abstract identifies VEEV as an alphavirus and describes mosquito transmission, severe disease in horses and other equids, and human infections. But it limits equine virulence chiefly to epizootic strains; it says enzootic strains are typically avirulent for equids and can cause human disease through rodent–mosquito spillover. The claim omits that distinction and implies equine disease is characteristic of VEEV generally. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [4] Ronca, S.E., Dineley, K.T., and Paessler, S. (2016). Neurological Sequelae Resulting from Encephalitic Alphavirus Infection. Front. Microbiol., 7. sourcePartly supported

  The Introduction identifies VEEV as a mosquito-transmitted encephalitic alphavirus, and Clinical Cases > Venezuelan Equine Encephalitis reports its isolation in equines and subsequent human disease. Neither passage establishes that VEEV causes a highly virulent CNS disease in horses or other equines, or characterizes human infections as spillover. Page numbers are not available in our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

Neurotropic pathogens such as human herpes virus, herpes simplex virus, hepatitis C virus, cytomegalovirus, varicella-zoster virus, and Epstein-Barr virus are associated with Alzheimer's disease neuropathology.

“For example, neurotropic pathogens, such as human herpes virus (HHV), herpes simplex virus (HSV), hepatitis C virus (HCV), cytomegalovirus, varicella-zoster virus, and Epstein–Barr virus are associated with Alzheimer’s disease (AD) neuropathology [10,11,12,13].”

• cites [10] Levine, 2023, Virus exposure and neurodegenerative disease risk across national biobanks, Neuron sourcePartly supported

  The Discussion reports literature suggesting associations of HSV encephalitis and hepatitis with AD, and EBV with dementia. The Results associate varicella-zoster virus with multiple sclerosis and vascular dementia, not AD. These passages concern disease risk rather than AD neuropathology, and do not establish the claimed associations for every listed pathogen, including cytomegalovirus. Page numbers are not provided in our copy. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites [11] Romanescu, C., Schreiner, T.G., and Mukovozov, I. (2022). The Role of Human Herpesvirus 6 Infection in Alzheimer’s Disease Pathogenicity—A Theoretical Mosaic. J. Clin. Med., 11. sourcePartly supported

  The Introduction (page unavailable) discusses HHV-6, HSV-1, CMV, and HCV in relation to Alzheimer’s disease mechanisms and reports higher viral quantities in some AD specimens than in controls. Section 4.3 also links viral infections to AD pathology, but the searched passages do not support the sentence’s inclusion of varicella-zoster or Epstein–Barr virus. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [12] Feng, 2023, Mechanistic insights into the role of herpes simplex virus 1 in Alzheimer’s disease, Front. Aging Neurosci. sourcePartly supported

  The Introduction (page unavailable) links HSV-1 and HSV-2 infection to AD and AD-like neurodegeneration, and identifies HSV-1 as human herpesvirus 1. It does not establish an AD-neuropathology association for hepatitis C virus, cytomegalovirus, varicella-zoster virus, or Epstein–Barr virus; it discusses Epstein–Barr virus in relation to multiple sclerosis instead. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [13] Mody, 2023, Cytomegalovirus infection induces Alzheimer’s disease-associated alterations in tau, J. Neurovirol. sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

VEEV triggers neurological sequelae in survivors that can be characterized by cognitive, motor, and sensory deficits likely through direct neuronal and glial cell infection.

“It is well documented that VEEV triggers neurological sequelae in survivors that can be characterized by cognitive, motor, and sensory deficits likely through direct neuronal and glial cell infection [7,8].”

• cites [7] Williams, 2023, Deep spatial profiling of Venezuelan equine encephalitis virus reveals increased genetic diversity amidst neuroinflammation and cell death during brain infection, J. Virol. sourcePartly supported

  The Introduction describes VEEV infection and damage of neurons, and the Discussion links infected brain regions to motor control and sensory pathways (page numbers unavailable). But the paper studies acute infection in mice, not cognitive, motor, and sensory deficits in survivors. Its Results describe microglia surrounding infected neurons and astrocytes responding to infection, not direct infection of glial cells. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [8] Schoneboom, 1999, Astrocytes as targets for Venezuelan equine encephalitis virus infection, J. Neurovirol. sourcePartly supported

  The introduction (p. 2) describes neuronal infection and degeneration, and the Discussion (pp. 6–7) shows astrocyte infection in vitro and proposes that it could contribute to VEE encephalitis. The paper does not report neurological sequelae in survivors or characterize cognitive, motor, and sensory deficits, so it does not establish the claimed link between those deficits and neuronal or glial infection. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

Tg2576 mice exhibit elevated Aβ from 2 months old onward, plaques after 6 months old, and cognitive deficits beginning at 5 months old.

“Tg2576 mice exhibit elevated Aβ from 2 months old onward, plaques after 6 months old, and cognitive deficits beginning at 5 months old [32,33,34].”

• cites [32] Kawarabayashi, 2001, Age-dependent changes in brain, CSF, and plasma amyloid (beta) protein in the Tg2576 transgenic mouse model of Alzheimer’s disease, J. Neurosci. sourcePartly supported

  The section “Cored plaques appear early in Tg2576 brain” (page unavailable) reports cored plaques at 7–8 months, supporting plaques after 6 months. The Discussion (page unavailable) places the onset of insoluble Aβ changes at 6–7 months, not 2 months; the introduction mentions age-dependent behavioral deficits but gives no 5-month onset. Thus the cited paper does not support the two specific early ages in the claim. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [33] Dineley, 2002, Accelerated plaque accumulation, associative learning deficits, and up-regulation of alpha 7 nicotinic receptor protein in transgenic mice co-expressing mutant human presenilin 1 and amyloid precursor proteins, J. Biol. Chem. sourcePartly supported

  The Results (page not supplied) report that APP-only Tg2576 mice were plaque-free at 7 months but had occasional cortical plaques at 9 months. The paper also reports impaired contextual fear learning at 5 months, but only after the two-pairing protocol; five pairings rescued that impairment. Our copy does not establish that Aβ was elevated from 2 months onward. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [34] Hernandez, 2010, Loss of alpha7 nicotinic receptors enhances beta-amyloid oligomer accumulation, exacerbating early-stage cognitive decline and septohippocampal pathology in a mouse model of Alzheimer’s disease, J. Neurosci. sourcePartly supported

  The Results section reports impaired contextual fear conditioning in 5-month-old APP (Tg2576-derived) mice, supporting cognitive deficits at that age. Our copy does not establish elevated Aβ beginning at 2 months or plaques appearing after 6 months; its reference to a 6-month onset concerns a soluble Aβ oligomer, not plaques. Page numbers are unavailable in our copy. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

May combine two claims.

A previous study demonstrated a robust immune phenotype in the CNS and altered learning and memory outcomes aligning with AD neuropathology in a chronic model of VEEV TC-83 infection.

“We previously demonstrated a robust immune phenotype in the CNS and altered learning and memory outcomes that align with the neuropathology of AD, in a chronic model of VEEV TC-83 infection [39].”

• cites [39] Fongsaran, 2024, Arbovirus infection increases the risk for the development of neurodegenerative disease pathology in the murine model, Brain Behav. Immun. Health sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Tg2576 mice are predisposed to acquire amyloid beta tangles and AD neuropathology.

“given that these mice are predisposed to acquire amyloid beta tangles and AD neuropathology [45].”

• cites [45] Schaeffer, 2011, Insights into Alzheimer disease pathogenesis from studies in transgenic animal models, Clinics sourcePartly supported

  The 'Transgenic mouse models of Alzheimer disease' section reports that Tg2576 mice develop age-dependent Aβ deposition, senile plaques, and associated abnormalities. It does not say Tg2576 mice develop 'amyloid beta tangles': it describes neurofibrillary tangles in TAPP mice produced by crossing Tg2576 with a mutant-Tau line. No page numbers are provided in the supplied passages. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

Inflammation induces the activation of indoleamine 2,3-dioxygenase (IDO) and diverts tryptophan metabolism from serotonin to kynurenine, reducing the availability of CNS-localized serotonin.

“Moreover, inflammation induces the activation of indoleamine 2,3-dioxygenase (IDO) and diverts TRP metabolism from serotonin to KYN, reducing the availability of CNS-localized serotonin [23].”

• cites [23] Huang, 2023, Tryptophan Metabolism in Central Nervous System Diseases: Pathophysiology and Potential Therapeutic Strategies, Aging Dis. sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Other neurotropic viruses, including chikungunya virus, activate the kynurenine pathway through exerting antiviral effects and exacerbating inflammatory responses.

“other neurotropic viruses, including chikungunya virus (CHIKV), activate the KP, through exerting antiviral effects and exacerbating inflammatory responses [42].”

• cites [42] Alves de Souza, T.M., Fernandes-Santos, C., Araujo da Paixao de Oliveira, J., Tome, L.C.T., Fiestas-Solorzano, V.E., Nunes, P.C.G., Guimaraes, G.M.C., Sanchez-Arcila, J.C., Paiva, I.A., and de Souza, L.J. (2022). Increased Indoleamine 2,3-Dioxygenase 1 (IDO-1) Activity and Inflammatory Responses during Chikungunya Virus Infection. Pathogens, 11. sourcePartly supported

  The Discussion reports increased IDO-1 activity during early CHIKV infection and suggests it could have an antiviral effect. But it says IDO-1 may protect against uncontrolled immune responses and attenuate inflammation—not exacerbate it. The paper also does not establish this finding for other neurotropic viruses. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

The kynurenine pathway is the major route of degradation of tryptophan.

“The kynurenine pathway (KP) is the major route of degradation of TRP [17].”

• cites [17] Mithaiwala, M.N., Santana-Coelho, D., Porter, G.A., and O’Connor, J.C. (2021). Neuroinflammation and the Kynurenine Pathway in CNS Disease: Molecular Mechanisms and Therapeutic Implications. Cells, 10. sourceSupported

May combine two claims.

Inflammatory conditions stimulate tryptophan degradation and are related to increased levels of kynurenine pathway metabolites in the brain, including neuroprotective KYNA and neurotoxic QUIN.

“This aligns with the notion that inflammatory conditions, despite their generation, stimulate TRP degradation and are related to increased levels of KP metabolites in the brain [23], including the neuroprotective KYNA and neurotoxic QUIN [44].”

• cites [23] Huang, 2023, Tryptophan Metabolism in Central Nervous System Diseases: Pathophysiology and Potential Therapeutic Strategies, Aging Dis. sourceSupported
• cites [44] Ostapiuk, 2022, Kynurenic acid in neurodegenerative disorders-unique neuroprotection or double-edged sword?, CNS Neurosci. Ther. sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Several viral infections, including HIV, HCV, and HSV, increase activation of the kynurenine pathway, which is implicated in the neurological and cognitive impairments of patients with HIV, HCV, and HSV.

“Several viral infections, including HIV [19], HCV [20], and HSV [21] increase activation of the KP, which interestingly is implicated in the neurological and cognitive impairments of patients with HIV, HCV, and HSV [21,22].”

• cites [19] Huengsberg, 1998, Serum kynurenine-to-tryptophan ratio increases with progressive disease in HIV-infected patients, Clin. Chem. sourceNot checked — no full text of the source
• cites [20] Peyron, 2007, Motor cortex stimulation for neuropathic pain: From phenomenology to mechanisms, Neuroimage sourceNot checked — no full text of the source
• cites [21] Atlas, 2013, Sustained elevation of kynurenic Acid in the cerebrospinal fluid of patients with herpes simplex virus type 1 encephalitis, Int. J. Tryptophan Res. sourcePartly supported

  The Discussion reports elevated cerebrospinal-fluid kynurenic acid in herpes simplex encephalitis and describes activation of the kynurenine pathway in that condition. It also suggests that kynurenic acid may contribute to cognitive deficits after herpes simplex encephalitis and HIV-1 encephalitis. The paper does not address HCV-related cognitive impairment; the separate HCV activation claim is cited to another source. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [22] Baran, 2012, Kynurenic Acid Metabolism in Various Types of Brain Pathology in HIV-1 Infected Patients, Int. J. Tryptophan Res. sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Increasing experimental and epidemiological evidence indicates that viral infections are an environmental risk factor for the development of neurodegeneration and neurological sequelae.

“Although somewhat controversial, increasing experimental and epidemiological evidence indicates that viral infections are an environmental risk factor for the development of neurodegeneration and neurological sequelae [9].”

• cites [9] Blackhurst, 2023, Viral pathogens increase risk of neurodegenerative disease, Nat. Rev. Neurol. sourceSupported

Classified as probably not a substantial claim. May combine two claims.

Breakdown of tryptophan along the kynurenine pathway mediates generation of the neuroactive metabolites KYNA and QUIN, which are linked to a variety of neurodegenerative diseases.

“given that the breakdown of TRP along the KP mediates the generation of the neuroactive metabolites KYNA and QUIN, which are linked to a variety of neurodegenerative diseases [41].”

• cites [41] Campbell, 2014, Kynurenines in CNS disease: Regulation by inflammatory cytokines, Front. Neurosci. sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Multiple preclinical and clinical studies indicate that VEEV leads to increased neuroinflammatory profiles and potential demyelination.

“Multiple preclinical and clinical studies indicate that VEEV leads to increased neuroinflammatory profiles and potential demyelination [7].”

• cites [7] Williams, 2023, Deep spatial profiling of Venezuelan equine encephalitis virus reveals increased genetic diversity amidst neuroinflammation and cell death during brain infection, J. Virol. sourceSupported

May combine two claims.

The paper previously demonstrated a robust immune phenotype in the CNS and altered learning and memory in a chronic model of VEEV TC-83 infection.

“We previously demonstrated a robust immune phenotype in the CNS and altered learning and memory in a chronic model of VEEV TC-83 infection [39].”

• cites [39] Fongsaran, 2024, Arbovirus infection increases the risk for the development of neurodegenerative disease pathology in the murine model, Brain Behav. Immun. Health sourceSupported

May combine two claims.

Clinical studies identified heightened IDO activity, increased KYN/TRP ratios, and increased concentrations of TNF-α, IL-6, IFN-γ, CCL2, and CXCL10 in CHIKV patients.

“This is further supported by clinical studies identifying heightened IDO activity, increased KYN/TRP ratios, and increase concentrations of TNF-α, IL-6, IFN-γ, CCL2, and CXCL10 in CHIKV patients [42].”

• cites [42] Alves de Souza, T.M., Fernandes-Santos, C., Araujo da Paixao de Oliveira, J., Tome, L.C.T., Fiestas-Solorzano, V.E., Nunes, P.C.G., Guimaraes, G.M.C., Sanchez-Arcila, J.C., Paiva, I.A., and de Souza, L.J. (2022). Increased Indoleamine 2,3-Dioxygenase 1 (IDO-1) Activity and Inflammatory Responses during Chikungunya Virus Infection. Pathogens, 11. sourceSupported

May combine two claims.

At 3 months old, Tg2576 mice do not have detectable brain pathology or cognitive impairment and are considered at a prodromal stage of AD.

“Thus, at 3 months old, Tg2576 mice do not have detectable brain pathology or cognitive impairment and are considered at a prodromal stage of AD [35].”

• cites [35] Ashe, 2010, Probing the biology of Alzheimer’s disease in mice, Neuron sourcePartly supported

  Sections 3.2 and 3.3 describe APP-transgenic mice as models of the pre-dementia or asymptomatic phase of AD, broadly supporting the stage characterization. They do not establish that Tg2576 mice specifically lack detectable brain pathology or cognitive impairment at 3 months old; section 3.2 also notes that APP-transgenic mice can develop plaques and memory loss. Page numbers are unavailable in our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

During tryptophan degradation, kynurenine is produced and accounts for diverse biological functions, including regulation of immune responsivity and involvement in immune-mediated disorders.

“During TRP degradation, the bioactive compound kynurenine (KYN) is produced and accounts for diverse biological functions, including regulation of the immune responsivity and involvement in immune-mediated disorders [18].”

• cites [18] Huang, 2020, IDO and Kynurenine Metabolites in Peripheral and CNS Disorders, Front. Immunol. sourceSupported

Classified as probably not a substantial claim. May combine two claims.

Increased IDO expression is responsible for the catabolism of TRP in the KYN degradation pathway and is canonically upregulated by inflammatory mechanisms.

“Increased IDO expression is responsible for the catabolism of TRP in the KYN degradation pathway [36] and is canonically upregulated by inflammatory mechanisms [37,38].”

• cites [36] Taylor, 1991, Relationship between interferon-gamma, indoleamine 2,3-dioxygenase, and tryptophan catabolism, FASEB J. sourceNot checked — no full text of the source
• cites [37] Shimizu, 1978, Indoleamine 2,3-dioxygenase. Purification and some properties, J. Biol. Chem. sourceNot checked — no full text of the source
• cites [38] Mbongue, 2015, The Role of Indoleamine 2, 3-Dioxygenase in Immune Suppression and Autoimmunity, Vaccines sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Elevated QUIN levels in leukocytes during inflammatory responses contribute to increased NAD+.

“Several studies indicate elevated QUIN levels in leukocytes, during inflammatory responses, contribute to increased NAD+ [61,62].”

• cites [61] Moffett, 2020, Quinolinate as a Marker for Kynurenine Metabolite Formation and the Unresolved Question of NAD(+) Synthesis During Inflammation and Infection, Front. Immunol. sourcePartly supported

  The Discussion section on Quin accumulation reports elevated intracellular Quin in immune cells and says it could support sustained conversion to NAD+, but presents that role as a possibility rather than an established effect. The section on NAD+ synthesis outside the liver also reports that IFN-γ treatment alone decreased NAD+ levels in human monocytes and macrophages; increases were observed when PARP was inhibited. Page numbers are not available in our copy. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [62] Santamaria, 2012, Quinolinic Acid, an endogenous molecule combining excitotoxicity, oxidative stress and other toxic mechanisms, Int. J. Tryptophan Res.Not checked yet

  Not checked in the free run.

May combine two claims.

Mean KYN/TRP ratio values were 0.033 μg/mL in saline-inoculated mice and 0.083 μg/mL in VEEV TC-83-inoculated WT mice.

“Specifically, mean values of 0.033 µg/mL in saline-inoculated mice and 0.083 µg/mL in VEEV TC-83-inoculated WT mice were measured (n = 16; * p < 0.05, Figure 3E).”

May combine two claims.

KYN/TRP ratios were increased in WT mice infected with VEEV TC-83 and in Tg2576 mice when compared to uninfected WT mice.

“We measured increased KYN/TRP ratios in WT mice infected with VEEV TC-83 and in Tg2576 mice when compared to uninfected WT mice.”

May combine two claims.

During immune activation, the kynurenine pathway plays a more active role in VEEV TC-83-infected cells, leading to increases in the abundance of transcripts related to the kynurenine pathway of tryptophan metabolism.

“Thus, during immune activation, the kynurenine pathway plays a more active role in the VEEV TC-83-infected cells, leading to increases in the abundance of transcripts related to the kynurenine pathway of tryptophan metabolism.”

• AssumptionRests on an assumption: KYN is regulated by the levels and functional activity of IDO.

Probably not a substantial claim: may not pass S3 (load-bearing).

In human cases of VEEV infection, approximately 4-14% of patients report neurological complications including seizures, photophobia, behavioral changes, neuromuscular weakness, and paralysis.

“In human cases of VEEV infection, approximately 4–14% of patients report neurological complications including seizures, photophobia, behavioral changes, neuromuscular weakness, and paralysis [5,6].”

• cites [5] Weaver, 2004, Venezuelan equine encephalitis, Annu. Rev. Entomol. sourceNot checked — no full text of the source
• cites [6] Johnson, 1974, Venezuelan equine encephalitis, Adv. Vet. Sci. Comp. Med.Not checked yet

  Not checked in the free run.

Classified as probably not a substantial claim. May combine two claims.

Tg2576 overexpresses a mutant form of APP (isoform 695) with the Swedish mutation (KM670/671NL), resulting in elevated levels of amyloid beta (Aβ) and ultimately amyloid plaques.

“It overexpresses a mutant form of APP (isoform 695) with the Swedish mutation (KM670/671NL), resulting in elevated levels of amyloid beta (Aβ) and ultimately amyloid plaques [31].”

• cites [31] Hsiao, 1996, Correlative memory deficits, Abeta elevation, and amyloid plaques in transgenic mice, Science sourceNot checked — no full text of the source

May combine two claims.

The KYN/TRP ratio is a reliable indicator for tracking TRP degradation, which further implies enhanced IDO activity.

“The KYN/TRP ratio, particularly when comparing the concentration of IDO’s first product to the substrate, is a reliable indicator for tracking TRP degradation, which further implies enhanced IDO activity [48].”

• cites [48] Schrocksnadel, 2006, Monitoring tryptophan metabolism in chronic immune activation, Clin. Chim. Acta sourceNot checked — no full text of the source

May combine two claims.

The observed relationship between VEEV TC-83 infection and the progression of AD may contribute to the development of AD, leading to elevated levels of Aβ and the formation of amyloid plaques.

“The observed relationship between VEEV TC-83 infection and the progression of AD may contribute to the development of AD, leading to elevated levels of Aβ and the formation of amyloid plaques [31].”

• cites [31] Hsiao, 1996, Correlative memory deficits, Abeta elevation, and amyloid plaques in transgenic mice, Science sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Tryptophan degradation is diverted to KYN following IDO activity.

“since TRP degradation is diverted to KYN following IDO activity [46]”

• cites [46] Quak, 2014, Does tryptophan degradation along the kynurenine pathway mediate the association between pro-inflammatory immune activity and depressive symptoms?, Psychoneuroendocrinology sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Quinolinic acid, a QUIN precursor, contributes to neuroinflammation and is implicated in various neurodegenerative diseases.

“previous studies showing that quinolinic acid (QA), a QUIN precursor, contributes to neuroinflammation and is implicated in various neurodegenerative diseases [55,56,57].”

• cites [55] Lim, 2017, Involvement of the kynurenine pathway in the pathogenesis of Parkinson’s disease, Prog. Neurobiol. sourceNot checked — no full text of the source
• cites [56] Guillemin, 2005, Implications for the kynurenine pathway and quinolinic acid in amyotrophic lateral sclerosis, Neurodegener. Dis. sourceNot checked — no full text of the source
• cites [57] Severino, 2015, N-methyl-D-aspartate preconditioning prevents quinolinic acid-induced deregulation of glutamate and calcium homeostasis in mice hippocampus, Neurotox Res. sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

These immune responses are intertwined with other biological processes that can further influence the inflammation or metabolism of critical biological processes, thus impacting the brain.

“These immune responses are intertwined with other biological processes that can further influence the inflammation or metabolism of critical biological processes, thus impacting the brain [16].”

• cites [16] Lovelace, 2017, Recent evidence for an expanded role of the kynurenine pathway of tryptophan metabolism in neurological diseases, Neuropharmacology sourceNot checked — no full text of the source

May combine two claims.

IDO activity likely follows innate immune responses to VEEV TC-83 infection and serves as the initiation step of tryptophan metabolism in the CNS.

“further suggesting that IDO activity likely follows innate immune responses to VEEV TC-83 infection and serves as the initiation step of TRP metabolism in the CNS [43].”

• cites [43] Guillemin, 2005, Expression of indoleamine 2,3-dioxygenase and production of quinolinic acid by human microglia, astrocytes, and neurons, Glia sourceNot checked — no full text of the source

• AssumptionRests on an assumption: The kynurenine pathway is triggered by immunological events.

May combine two claims.

IDO may be associated with the development of neurological damage and may play important roles in behavioral impairment affecting behavioral performance.

“These results suggest that IDO may be associated with the development of neurological damage, playing important roles in behavioral impairment affecting behavioral performance.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The Tg2576 model is one of the most well characterized and widely used mouse models of AD.

“The Tg2576 model is one of the most well characterized and widely used mouse models of AD.”

• cites [31] Hsiao, 1996, Correlative memory deficits, Abeta elevation, and amyloid plaques in transgenic mice, Science sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Two-sided power analysis indicates a minimum sample size of 10 animals per group.

“Two-sided power analysis indicates a minimum sample size of 10 animals per group.”

Probably not a substantial claim: may not pass S3 (load-bearing).

In certain assays, the sample size did not encompass all animals due to the unavailability of sufficient samples from each group.

“In certain assays, the sample size did not encompass all animals due to the unavailability of sufficient samples from each group.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Neurotoxicity in neurons is triggered by overstimulation of NMDA receptors, leading to disruptions in intracellular Ca2+ homeostasis and free radical formation.

“Neurotoxicity in neurons is triggered by the overstimulation of NMDA receptors, leading to disruptions in intracellular Ca2+ homeostasis and free radical formation [53,54].”

• cites [53] Ryu, 2004, Blockade of quinolinic acid-induced neurotoxicity by pyruvate is associated with inhibition of glial activation in a model of Huntington’s disease, Exp. Neurol. sourceNot checked — no full text of the source
• cites [54] Escalante, 1998, Nitric oxide synthase inhibition prevents acute quinolinate-induced striatal neurotoxicity, Neurochem. Res. sourceNot checked — no full text of the source

May combine two claims.

There is a relationship between all outcomes and the levels of KP metabolites in the CNS, showing a significant enhancement of downstream metabolites.

“This indicates a relationship between all outcomes and the levels of KP metabolites in the CNS, showing a significant enhancement of downstream metabolites.”

Probably not a substantial claim: may not pass S3 (load-bearing).

QUIN is a neurotoxin that can induce apoptosis in neurons, oligodendrocytes, and astrocytes, which is characteristic of neurodegenerative disorders.

“QUIN is a neurotoxin that can induce apoptosis in neurons, oligodendrocytes, and astrocytes, which is characteristic of neurodegenerative disorders [51,52].”

• cites [51] Guillemin, 2012, Quinolinic acid, the inescapable neurotoxin, FEBS J. sourceNot checked — no full text of the source
• cites [52] Pineda, 2013, Quinolinic acid: An endogenous neurotoxin with multiple targets, Oxid. Med. Cell Longev.Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

In AD, there is heightened sensitivity to IDO activity, which may be triggered via heightened neuroinflammatory pathways.

“suggesting that in AD, there is heightened sensitivity to IDO activity, which may be triggered via heightened neuroinflammatory pathways.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Based on the means and variances of the majority of the behavior data collected, and to account for infection-related variability, the study included a sample size between 10-16 animals per group.

“Based on the means and variances of the majority of the behavior data we collected, and to account for infection-related variability, we included a sample size between 10–16 animals per group.”

May combine two claims.

The acceleration of AD by viral infection is likely multifactorial but triggered by the host immune response to viruses.

“This is likely multifactorial but triggered by the host immune response to viruses.”

May combine two claims.

Observed changes in KP metabolites, such as QUIN and NAD+, suggest a differential activation of the KP that may play a role in the progression and severity of virus infection.

“The observed changes in KP metabolites, such as QUIN and NAD+, suggest a differential activation of the KP that may play a role in the progression and severity of virus infection.”

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Viral infection prior to AD diagnosis may accelerate the manifestation of AD.

“In parallel, viral infection prior to AD diagnosis may accelerate the manifestation of AD, while viral infection during AD, as tested in this study, may accelerate AD progression.”

May combine two claims.

The findings suggest a notable decline in spatial ability and memory dysfunction.

“This reflects a cautious approach and suggests a notable decline in spatial ability and memory dysfunction.”

May combine two claims.

KP involvement in neuropathogenesis directs KP metabolism toward the neurotoxic metabolite QUIN and limits neuroprotection.

“Our studies implicate a mechanism of KP involvement in neuropathogenesis, directing KP metabolism toward the neurotoxic metabolite QUIN and limiting neuroprotection.”

May combine two claims.

Cytokines are upregulated in response to VEEV TC-83 and mediate the induction of IDO expression.

“These findings indicate that cytokines are upregulated in response to VEEV TC-83 and mediate the induction of IDO expression.”

May combine two claims.

Both QUIN and NAD+ are possibly involved in acquisition and contribute to behavioral changes influencing the learning of active avoidance responses, resulting in delayed response latencies.

“Thus, taken together, we found that both QUIN and NAD+ are possibly involved in the acquisition and contribute to behavioral changes influencing the learning of active avoidance responses, resulting in delayed response latencies.”