Effects of Probiotics on Colitis-Induced Exacerbation of Alzheimer's Disease in AppNL-G-F Mice.

Alzheimer's disease (AD) is characterized by progressive cognitive decline and is a leading cause of death in the United States. Neuroinflammation has been implicated in the progression of AD, and several recent studies suggest that peripheral immune dysfunction may influence the disease. Continuing evidence indicates that intestinal dysbiosis is an attribute of AD, and inflammatory bowel disease (IBD) has been shown to aggravate cognitive impairment. Previously, we separately demonstrated that an IBD-like condition exacerbates AD-related changes in the brains of the AppNL-G-F mouse model of AD, while probiotic intervention has an attenuating effect. In this study, we investigated the combination of a dietary probiotic and an IBD-like condition for effects on the brains of mice. Male C57BL/6 wild type (WT) and AppNL-G-F mice were randomly divided into four groups: vehicle control, oral probiotic, dextran sulfate sodium (DSS), and DSS given with probiotics. As anticipated, probiotic treatment attenuated the DSS-induced colitis disease activity index in WT and AppNL-G-F mice. Although probiotic feeding significantly attenuated the DSS-mediated increase in WT colonic lipocalin levels, it was less protective in the AppNL-G-F DSS-treated group. In parallel with the intestinal changes, combined probiotic and DSS treatment increased microglial, neutrophil elastase, and 5hmC immunoreactivity while decreasing c-Fos staining compared to DSS treatment alone in the brains of WT mice. Although less abundant, probiotic combined with DSS treatment demonstrated a few similar changes in AppNL-G-F brains with increased microglial and decreased c-Fos immunoreactivity in addition to a slight increase in Aß plaque staining. Both probiotic and DSS treatment also altered the levels of several cytokines in WT and AppNL-G-F brains, with a unique increase in the levels of TNFα and IL-2 being observed in only AppNL-G-F mice following combined DSS and probiotic treatment. Our data indicate that, while dietary probiotic intervention provides protection against the colitis-like condition, it also influences numerous glial, cytokine, and neuronal changes in the brain that may regulate brain function and the progression of AD.

Inflammatory mechanisms in neurodegeneration.

This review discusses the profound connection between microglia, neuroinflammation, and Alzheimer's disease (AD). Theories have been postulated, tested, and modified over several decades. The findings have further bolstered the belief that microglia-mediated inflammation is both a product and contributor to AD pathology and progression. Distinct microglia phenotypes and their function, microglial recognition and response to protein aggregates in AD, and the overall role of microglia in AD are areas that have received considerable research attention and yielded significant results. The following article provides a historical perspective of microglia, a detailed discussion of multiple microglia phenotypes including dark microglia, and a review of a number of areas where microglia intersect with AD and other pathological neurological processes. The overall breadth of important discoveries achieved in these areas significantly strengthens the hypothesis that neuroinflammation plays a key role in AD. Future determination of the exact mechanisms by which microglia respond to, and attempt to mitigate, protein aggregation in AD may lead to new therapeutic strategies.

Effect of CO2 Laser-Assisted Titanium Tetra-fluoride on Demineralization of Enamel Around Orthodontic Brackets.

Introduction: One of the clinical problems following orthodontic treatment is white spot lesions around orthodontic brackets due to enamel demineralization. Confronting enamel demineralization during fixed treatments has long been a challenge for orthodontists. The aim of this in vitro study was to evaluate the effect of CO2 laser and Titanium Tetra-fluoride (TiF4) application on the prevention of enamel demineralization around orthodontic brackets. Methods: Eighty permanent premolars were selected and bonded with brackets. They were randomly divided into four groups (n=20): topical titanium tetra-fluoride gel 4% (TiF4), CO2 laser (10.6 µm wavelength for 10 seconds, peak power=291 W), fluoride+laser (F+L) and control (C). All specimens were demineralized for 10 days in a 0.2 M acetate buffer solution. The mean lesion depths were determined by using polarized light microscopy. Results: The mean depth of lesion was the highest in the C group and then decreased in the TiF4, CO2 laser, and F+L groups, respectively. The difference between all groups was significant (P<0.05), except for the CO2 laser and F+L groups. Conclusion: The lowest amount of demineralization around the orthodontic brackets was observed in the L+F group, followed by the CO2 laser, TiF4, and control groups, respectively.

Investigating the combined effect of copper, zinc, and iron ions on truncated and full-length Aß peptides: insights from molecular dynamics simulation.

The truncated Aß1 - 16 peptide containing the metal-binding domain is frequently used in in silico and experimental investigations because it is more soluble and thus more suitable for studies in solution and does not form amyloids. Several spectroscopic studies have shown that the metal binding of Aß1 - 16 is very similar to that of the full-length Aß1 - 42. However, since small changes can have a significant impact on aggregation, further experimental and theoretical are needed to elucidate the detailed structures of truncated and full-length Aß. In this research, the binding of copper ion to the Aß1 - 16 and Aß1 - 42 has been studied by molecular dynamics simulation method. To investigate the effect of copper ion on beta-amyloid peptide structure, the simulations were repeated in the copper and zinc ions, copper and iron binary system, and the copper, zinc and iron ions ternary system. The conformation factor was calculated to calculate the binding affinity of copper ion to beta-amyloid peptide residues. The results showed that the initial 16 residues of the beta-amyloid peptide have high binding affinity for copper ions, and histidine 13 and histidine 14 have significantly higher binding affinity for copper ions in all studied systems. Zinc and iron ions were found to reduce the conformational factor of peptide residues in binding to copper ions, and the aggregation tendency was lower in the truncated structure. The SASA results suggest that the side chains of peptide residues are more affected by shortening and the presence of ions.Communicated by Ramaswamy H. Sarma.

Angiogenetic and anti-inflammatory effects of photobiomodulation on bone regeneration in rat: A histopathological, immunohistochemical, and molecular analysis.

Post-surgical bone defects require new alternative approaches for a better healing process. For this matter, photobiomodulation therapy (PBMT) has been used in order to improve the process of healing, pain, and inflammation reduction and tissue rejuvenation. This study is set to evaluate the effect of PBMT on angiogenic and inflammatory factors for bone regeneration in rat post-surgical cranial defects. Thirty male Wistar rats were distributed accidentally into two groups (Subdivided into 3 groups according to their follow-up durations). During operation, an 8-mm critical-sized calvarial defect was made in each rat. A continuous diode laser was used (power density 100 mW/cm2, wavelength 810 nm, the energy density of 4 J/cm2). Bone samples were assessed histomorphometrically and histologically after hematoxylin and eosin (H&E) staining. ALP, PTGIR, OCN, and IL-1 levels were measured by RT-PCR. VEGF expression was studied by immunohistochemistry analysis. The level of IL-1 expression decreased significantly in the PBMT group compared to the control after 7 days (p < 0.05), while, the PTGIR level was improved significantly compared to the control group after 7 days. Furthermore, levels of OCN and ALP improved after PBM use; however, the alterations were not statistically meaningful (p > 0.05). Evaluation with IHC displayed a significant rise in VEGF expression after 3 days in the PBMT group compared to the control (p > 0.05). In this study's conditions, the results showed a meaningful alteration in osteogenic, inflammatory, and angiogenic mediators in post-surgical calvarial defect following PBMT. It appears that PBM can accelerate angiogenesis in the bone healing procedure which can be helpful in bone tissue engineering.

Gastrointestinal Changes and Alzheimer's Disease.

BACKGROUND: There is a well-described mechanism of communication between the brain and gastrointestinal system in which both organs influence the function of the other. This bi-directional communication suggests that disease in either organ may affect function in the other. OBJECTIVE: To assess whether the evidence supports gastrointestinal system inflammatory or degenerative pathophysiology as a characteristic of Alzheimer's disease (AD). METHODS: A review of both rodent and human studies implicating gastrointestinal changes in AD was performed. RESULTS: Numerous studies indicate that AD changes are not unique to the brain but also occur at various levels of the gastrointestinal tract involving both immune and neuronal changes. In addition, it appears that numerous conditions and diseases affecting regions of the tract may communicate to the brain to influence disease. CONCLUSION: Gastrointestinal changes represent an overlooked aspect of AD, representing a more system influence of this disease.

Gut Inflammation Induced by Dextran Sulfate Sodium Exacerbates Amyloid-ß Plaque Deposition in the AppNL-G-F Mouse Model of Alzheimer's Disease.

BACKGROUND: Although it is known that the brain communicates with the gastrointestinal (GI) tract via the well-established gut-brain axis, the influence exerted by chronic intestinal inflammation on brain changes in Alzheimer's disease (AD) is not fully understood. We hypothesized that increased gut inflammation would alter brain pathology of a mouse model of AD. OBJECTIVE: Determine whether colitis exacerbates AD-related brain changes. METHODS: To test this idea, 2% dextran sulfate sodium (DSS) was dissolved in the drinking water and fed ad libitum to male C57BL/6 wild type and AppNL-G-F mice at 6-10 months of age for two cycles of three days each. DSS is a negatively charged sulfated polysaccharide which results in bloody diarrhea and weight loss, changes similar to human inflammatory bowel disease (IBD). RESULTS: Both wild type and AppNL-G-F mice developed an IBD-like condition. Brain histologic and biochemical assessments demonstrated increased insoluble Aß1-40/42 levels along with the decreased microglial CD68 immunoreactivity in DSS treated AppNL-G-F mice compared to vehicle treated AppNL-G-F mice. CONCLUSION: These data demonstrate that intestinal dysfunction is capable of altering plaque deposition and glial immunoreactivity in the brain. This study increases our knowledge of the impact of peripheral inflammation on Aß deposition via an IBD-like model system.

Effect of an Educational Pamphlet on Knowledge and Performance of Fitness Trainers about Traumatic Dental Injuries.

Objectives : Traumatic dental injuries (TDIs) commonly occur in sport clubs. The knowledge and performance of fitness trainers play an important role in management of such injuries. This study sought to assess the effect of an educational pamphlet on knowledge level and performance of fitness trainers about TDIs in Tehran in 2018. Materials and Methods: In this interventional study, a pamphlet was designed to enhance the knowledge level of fitness trainers. Ninety-five fitness trainers were randomly divided into two groups of intervention and control (n=49 in the control group and n=46 in the interventional group), and were requested to fill out a valid and reliable researcher-designed questionnaire about TDIs before and 1 month after pamphlet distribution. The questionnaire consisted of three domains of demographic information, knowledge questions, and performance questions. The results were analyzed using SPSS 25 via the Chi-square test and repeated measures ANOVA considering the intervention as the between-subject factor. Results: The knowledge score of fitness trainers about TDIs was not adequately high in the intervention or the control group before the intervention. After the intervention, the performance of participants improved in both groups. This increase was significantly greater in the intervention group (P=0.035). There was no significant difference between the two groups in the knowledge domain (P=0.185). Conclusion: Educational pamphlets can effectively enhance the knowledge level of fitness trainers about TDIs. However, the magnitude of this effect was not significant in our study. Future studies are recommended to compare the efficacy of educational pamphlets with other educational tools.

Evaluation of antimicrobial photodynamic therapy on wounds infected by Staphylococcus aureus in animal models.

BACKGROUND: Antibiotic-resistant Staphylococcus aureus bacteria are one of the expanding challenges. The purpose of current study is to evaluate the antimicrobial effect of photodynamic therapy (aPDT) on wounds infected to Staphylococcus aureus. METHODS: In this study, 40 six-month-old rats were divided into 4 groups: control, photosensitizer (PS), laser, and aPDT. A full-thickness wound was created on their skin and it was infected by Staphylococcus aureus. For aPDT, the Indocyanine Green (Germany, Nürnberg, A.R.C. Laser, EmunDo) photosensitive agent and laser diod 810 nm (Germany, Nürnberg, A.R.C. Laser) was utilized. The wound healing procedure was monitored every 24 h until the 12th day with photography. The number of the bacteria was counted on the 12th day also. All results were compared using ANOVA and Tukey post hoc tests. Significance level was considered P-Value < 0.05. RESULTS: The average area of wound reduced in days 5-11th in photosensitizer, laser, and aPDT, respectively. The absolute colonization rate of bacteria in the wounds showed a significant decrease in two groups laser and aPDT compared to the control group. However, the lowest value was for the aPDT. CONCLUSION: In the conditions of this study, it emerged that aPDT and laser have an antimicrobial effect against antibiotic-resistant bacteria (particularly Staphylococcus aureus) and improve wound healing.

IGF-1R Inhibitor Ameliorates Neuroinflammation in an Alzheimer's Disease Transgenic Mouse Model.

Aging is a major risk factor for Alzheimer's disease (AD). Insulin-like growth factor-1 receptor (IGF-1R) regulates general aging and lifespan. However, the contribution of IGF-1 to age-related AD pathology and progression is highly controversial. Based on our previous work, AßPP/PS1 double transgenic mice, which express human mutant amyloid precursor protein (APP) and presenilin-1 (PS-1), demonstrated a decrease in brain IGF-1 levels when they were crossed with IGF-1 deficient Ames dwarf mice (df/df). Subsequently, a reduction in gliosis, amyloid-ß (Aß) plaque deposition, and Aß1-40/42 concentrations were observed in this mouse model. This supported the hypothesis that IGF-1 may contribute to the progression of the disease. To assess the role of IGF-1 in AD, 9-10-month-old male littermate control wild type and AßPP/PS1 mice were randomly divided into two treatment groups including control vehicle (DMSO) and picropodophyllin (PPP), a selective, competitive, and reversible IGF-1R inhibitor. The brain penetrant inhibitor was given ip. at 1 mg/kg/day. Mice were sacrificed after 7 days of daily injection and the brains, spleens, and livers were collected to quantify histologic and biochemical changes. The PPP-treated AßPP/PS1 mice demonstrated attenuated insoluble Aß1-40/42. Additionally, an attenuation in microgliosis and protein p-tyrosine levels was observed due to drug treatment in the hippocampus. Our data suggest IGF-1R signaling is associated with disease progression in this mouse model. More importantly, modulation of the brain IGF-1R signaling pathway, even at mid-life, was enough to attenuate aspects of the disease phenotype. This suggests that small molecule therapy targeting the IGF-1R pathway may be viable for late-stage disease treatment.

Salivary Aß Secretion and Altered Oral Microbiome in Mouse Models of AD.

BACKGROUND: Beta amyloid (Aß) peptide containing plaque aggregations in the brain are a hallmark of Alzheimer's Disease (AD). However, Aß is produced by cell types outside of the brain suggesting that the peptide may serve a broad physiologic purpose. OBJECTIVE: Based upon our prior work documenting expression of amyloid ß precursor protein (APP) in intestinal epithelium we hypothesized that salivary epithelium might also express APP and be a source of Aß. METHODS: To begin testing this idea, we compared human age-matched control and AD salivary glands to C57BL/6 wild type, AppNL-G-F , and APP/PS1 mice. RESULTS: Both male and female AD, AppNL-G-F , and APP/PS1 glands demonstrated robust APP and Aß immunoreactivity. Female AppNL-G-F mice had significantly higher levels of pilocarpine stimulated Aß 1-42 compared to both wild type and APP/PS1 mice. No differences in male salivary Aß levels were detected. No significant differences in total pilocarpine stimulated saliva volumes were observed in any group. Both male and female AppNL-G-F but not APP/PS1 mice demonstrated significant differences in oral microbiome phylum and genus abundance compared to wild type mice. Male, but not female, APP/PS1 and AppNL-G-F mice had significantly thinner molar enamel compared to their wild type counterparts. CONCLUSION: These data support the idea that oral microbiome changes exist during AD in addition to changes in salivary Aß and oral health.

A protocol for making and sectioning multiple embedded Swiss-rolls in a gelatin matrix.

The appropriate methodological approach for intestinal preparation enables researchers to create representative histological and immunostaining images which validate their biochemical data. The Swiss-roll technique was first introduced by Reilly and Kirsner in 1965. Later, Moolenbeek and Ruitenberg described a detailed procedure to longitudinally study the rodent intestine in 1981 [1]. In this publication, our slightly different approach for co-embedding four different Swiss-rolls in a gelatin block provides a full-length overview of cross-sectional colons on a single slide. This protocol allows for longitudinal histologic examination of multiple tissue samples on a single slide simultaneously. In this method, antigenicity is retained for immunohistology. In addition, the accessibility of samples during the prolonged hardening time required of the gelatin matrix allows the tissue samples to be adjusted/re-adjusted to provide the desired orientation and spatial arrangement for ideal cross sections with similar planes of section and optimum space utilization for slide mounting. Although not the focus of this protocol, the room temperature stability of the gelatin matrix and the ability to contain numerous tissue samples in a block allows the flexibility of performing thicker sections for free-floating tissue staining and ease of mounting a single gelatin sheet rather than individual tissue sections. This is a convenient approach for allowing precise preparation of multi-tissue blocks and simultaneous sectioning, staining, and slide mounting of tissue for subsequent comparisons. •A single gelatin block is prepared by simultaneously embedding at least four different intestinal Swiss-rolls.•The tissue orientation can be adjusted for each sample as desired which facilitates the comparison of different colon samples on a single gelatin section.•The gelatin sections containing tissue samples are stable at least overnight at room temperature for staining.

Comparison of Microleakage of Pedo Jacket Crowns and Stainless Steel Crowns Cemented with Different Cements.

OBJECTIVES: This study aimed to assess the microleakage of Pedo Jacket crowns compared to stainless steel crowns (SSCs) cemented with different luting cements. MATERIALS AND METHODS: In this in-vitro experimental study, 80 primary molars were randomly divided into four groups of 20 each. Groups 1 and 2 were subjected to standard tooth preparation for SSC. Crowns in group 1 were cemented with glass ionomer (GI), and crowns in group 2 were cemented with a resin-modified glass ionomer (RMGI) cement. In groups 3 and 4, minimal tooth preparation was performed for Pedo Jacket crowns, and the crowns were cemented with RMGI and Panavia resin cement, respectively. Microleakage was measured at mesial and distal surfaces in micrometers (µm), and the mean value for each tooth was calculated. Oneway analysis of variance (ANOVA) was applied to compare the microleakage of the four groups. RESULTS: Group 3 (Pedo Jacket cemented with RMGI) showed the highest microleakage (1523.83±250.32 µm) with significant differences with the remaining three groups (P<0.001). Microleakage in group 4 (Pedo Jacket cemented with Panavia) was significantly lower than that in the other three groups (301.25±219.53 µm, P<0.001). Groups 1 (SSCs cemented with GI) and 2 (SSCs cemented with RMGI) were not significantly different in terms of microleakage (P=0.49) although group 1 showed slightly higher microleakage than group 2 (598.43±260.85 µm versus 500.25±124.74 µm). CONCLUSION: Pedo Jacket crowns can serve as an acceptable esthetic alternative to SSCs if cemented with resin cements.

Soft-tissue esthetic outcome of single implants: Immediate placement in fresh extraction sockets versus conventional placement in healed sockets.

BACKGROUND: Immediate implant placement has advantages such as requiring fewer surgical procedures and decreased treatment time; however, unpredictable soft- and hard-tissue outcome is a problem. This study aimed to compare the soft-tissue esthetic outcome of single implants placed in fresh extraction sockets versus those placed in healed sockets. MATERIALS AND METHODS: This cross-sectional, retrospective study was performed on 42 patients who received single implants. Twenty-two patients with a mean age of 40.14 years received immediate implants while 18 patients with a mean age of 43.40 years were subjected to conventional (delayed) implant placement. The mean follow-up time was 14.42 ± 8.37 months and 18.25 ± 7.10 months in the immediate and conventional groups, respectively. Outcome assessments included clinical and radiographic examinations. The esthetic outcome was objectively rated using the pink esthetic score (PES). RESULTS: All implants fulfilled the success criteria. The mean PES was 8.54 ± 1.26 and 8.10 ± 1.65 in the immediate and conventional groups, respectively. This difference was not statistically significant (P = 0.329). The two PES parameters, namely, the facial mucosa curvature and facial mucosa level had the highest percentage of complete score. CONCLUSIONS: Immediate and conventional single implant treatments yielded comparable esthetic outcomes.

In utero exposure to fine particulate matter results in an altered neuroimmune phenotype in adult mice.

Environmental exposure to air pollution has been linked to a number of health problems including organ rejection, lung damage and inflammation. While the deleterious effects of air pollution in adult animals are well documented, the long-term consequences of particulate matter (PM) exposure during animal development are uncertain. In this study we tested the hypothesis that environmental exposure to PM 2.5 µm in diameter in utero promotes long term inflammation and neurodegeneration. We evaluated the behavior of PM exposed animals using several tests and observed deficits in spatial memory without robust changes in anxiety-like behavior. We then examined how this affects the brains of adult animals by examining proteins implicated in neurodegeneration, synapse formation and inflammation by western blot, ELISA and immunohistochemistry. These tests revealed significantly increased levels of COX2 protein in PM2.5 exposed animal brains in addition to changes in synaptophysin and Arg1 proteins. Exposure to PM2.5 also increased the immunoreactivity for GFAP, a marker of activated astrocytes. Cytokine concentrations in the brain and spleen were also altered by PM2.5 exposure. These findings indicate that in utero exposure to particulate matter has long term consequences which may affect the development of both the brain and the immune system in addition to promoting inflammatory change in adult animals.