Table 3.
Extracted data for secondary outcome.
| Author, Data, and Journal | Type of Study | Cell Lines, Tissue, Animals, and Databases | Antibodies, Antigens, Enzyme, and Proteins Investigated | Investigated Microorganisms |
Results |
|---|---|---|---|---|---|
| Wu et al., 2017, Brain Behav Immun [9] | Experimental study on mice and cell lines | (CatB−/−) mice, MG6 microglia cell line, | Pg- LPS, CatB |
P. gingivalis | CatB plays a critical role in the link between periodontitis and AD. |
| Hayashi et al. 2019, Exp Gerontol [10] | Experimental study on mice | Mice | Pg- LPS |
P. gingivalis | LPS pg exposure worsens the prognosis in AD |
| Poole rt al. 2013, J Alzheimers Dis [11] | Experimental study on brain tissue and cell lines |
Postmortem brain tissue, SVGp12 cells | LPS |
T. denticola
T. forsythia P. gingivalis |
Associative hypothesis between LPS pg and AD |
| Carter et al 2017, Journal of Alzheimer’s disease reports [12] | Bioinformatics study on databases | GWAS databases | 78 AD genes (GWAS) | Bacteria, viruses, fungi | The use of antibiotics and antifungals could reduce the effects of AD |
| Liu et al. 2017, Sci Rep [13] | Experimental study on mice and cell lines | Mice, MG6 microglia cell line | Arg-gingipain (Rgp) and Lys-gingipain (Kgp) | P. gingivalis | Data supports the infection hypothesis of Alzheimer’s disease |
| Laugish et al.2018, J Alzheimers Dis [14] | Clinical study | Patients with dementia (N = 20 in AD and N = 20 dementia non AD) | Tau protein (T-tau) and Amyloid β (Aβ1-42) in CFS(Cerebro spinal fluid) and Antibody levels in CFS e serum |
P. gingivalis
T. forsythia T. denticola T. socranskii A.actinomycetemcom |
The data does not support an associative hypothesis |
| Ide et al. 2016, PLoS One [15] | Observational cohort study | Patients with dementia (n = 60) | Serum inflammation, antibody and DNA assays | P.gingivalis | Study suggests there is a direct relationship between periodontitis and cognitive decline |
| Ishida et al. 2017, NPJ aging and mechanisms of disease [16] | Experimental study on mice | Mice | Amiloid β (Aβ) deposition, Aβ40, Aβ42, IL-1β and TNF-α | P. gingivalis | Concludes that periodontitis is truly a risk factor for AD |
| Dominy et al. 2019, Sci Adv [17] | Prospective pilot study | Mice and AD patients. | (Kgp), (Rgp), P. gingivalis 16S rRNA gene, P. gingivalis DNA in CFS, Aβ1–42 in cerebral mice tissue | P. gingivalis | P. gingivalis and gingipains in the brain play a central role in the pathogenesis of AD |
| Nie et al. 2019, J Alzheimers Dis [18] | Experimental study on mice | Mice | IL-1β, AβPP770, CatB, Aβ1-42, and Aβ3-42 in macrophage/monocites | P. gingivalis | Taken together, CatB may be a novel therapeutic target for preventing the periodontitis-related AD initiation and pathological progression. |
| Diaz-Zuniga et al. 2019, J Oral Microbiol [6] | Experimental study on cell line rat | Line rat cell (Mixed hippocampal cultures, Microglial cultures) | IL-1β, IL-6, TNF-α and Aβ1-42 | A. actinomycetemcomitans | Probable association between aparodontal disease sustained by Aggregatibacter and AD etiopathology |
| Sparks Stein et al. 2012, Alzheimer’s Dement [19] | Longitudinal study | Patient AD = 35, MCI = 46 and control = 76 | Antibody levels |
A. actinomycetemcomitans P. gingivalis, C. rectus, T. denticola, Fusobacterium nucleatum, T. forsythia |
Possible association between antibody levels and onset and progression of AD |
| Noble et al. 2014, PLoS One [20] | Case–cohort study | Patients who developed AD in follow-up | Serum IgG |
P. gingivalis, T. forsythia A. actinomycetemcomitans T. denticola, C. rectus, E. nodatum and A. naeslundii |
Serum IgG levels to common periodontal microbiota are associated with risk for developing incident AD |
| Carter et al. 2017, Front Aging Neurosci [21] | Bioinformatics study on databases | GWAS databases | P. gingivalis/host interactome | P. gingivalis | Supports the many documented relationships between P. gingivalis infection and AD or its comorbid conditions |
| Kamer et al. 2009, J Neuroimmunol [22] | Observational Study | 18 with AD and 16 cognitively normal | Plasma TNF-α, IL-1β and IL-6 levels, IgG antibody |
A. actinomycetemcomitans serotype b, T. forsythia and P. gingivalis |
Antibody levels to periodontal bacteria associate with AD and may help improve the clinical diagnosis of AD |