Development and characterization of amino donor-acceptor Stenhouse adducts.

Donor-acceptor Stenhouse adducts (DASAs) are molecular photoswitches spurring wide interest because of their dynamic photophysical properties, complex photoswitching mechanism, and diverse applications. Despite breakthroughs in modularity for the donor, acceptor, and triene compartments, the backbone heteroatom remains static due to synthetic challenges. We provide a predictive tool and sought-after strategy to vary the heteroatom, introduce amino DASA photoswitches, and analyze backbone heteroatom effects on photophysical properties. Amino DASA synthesis is enabled by aza-Piancatelli rearrangements on pyrrole substrates, imparting an aromaticity-breaking rearrangement that capitalizes on nitrogen's additional bonding orbital and the inductive properties of sulfonyl groups. Amino DASA structure is confirmed by single crystal X-ray diffraction, the photochromic properties are characterized, and the photoswitch isomerization is investigated. Overall, the discovered pyrrole rearrangement enables the study of the DASA backbone heteroatom compartment and furthers our insight into the structure-property relationship of this complex photoswitch.

Approaches to supratentorial brain tumours in children.

The differential diagnosis of supratentorial brain tumours in children can be challenging, especially considering the recent changes to the WHO classification of CNS tumours published in 2021. Many new tumour types have been proposed which frequently present in children and young adults and their imaging features are currently being described by the neuroradiology community. The purpose of this article is to provide guidance to residents and fellows new to the field of paediatric neuroradiology on how to evaluate an MRI of a patient with a newly diagnosed supratentorial tumour. Six different approaches are discussed including: 1. Tumour types, briefly discussing the main changes to the recent WHO classification of CNS tumours, 2. Patient age and its influence on incidence rates of specific tumour types, 3. Growth patterns, 4. Tumour location and how defining the correct location helps in narrowing down the differential diagnoses and 5. Imaging features of the tumour on DWI, SWI, FLAIR and post contrast sequences.

Rituximab as Treatment for Lupus Nephritis: Data From the Peruvian ALMENARA Lupus Cohort.

OBJECTIVE: The aim of this study was to evaluate the response to rituximab (RTX) as treatment for lupus nephritis (LN) in a Latin American Lupus cohort. METHODS: The medical records from LN patients from a single-center cohort spanning between January 2012 and December 2020 were reviewed. Demographic factors (age at diagnosis and baseline, gender), disease duration, previous and concomitant treatments, serum creatinine, and 24-hour proteinuria (24-HP) levels at baseline, and 6th and 12th months were obtained. Complete response (CR) or responder status was defined according to the LUNAR, AURORA-1, and BLISS-LN trials. RESULTS: Thirty-six patients received RTX as induction treatment; 32 (88.9%) were women. Their age at baseline and disease duration were 32.6 (11.7) and 7.6 (6.5) years, respectively. The time between renal biopsy and RTX use was 2.64 (4.41) years. At baseline, serum creatinine and 24-HP levels were 1.5 (1.5) mg/dL and 3.4 (2.8) g, respectively. At months 6 and 12, serum creatinine levels were 1.6 (1.6) and 1.6 (1.5) mg/dL, and 24-HP were 2.2 (2.2) and 1.6 (1.5) g, respectively. According to LUNAR and AURORA-1 criteria, CR at 6th and 12th months were 6/34 (17.6%) and 8/30 (26.7%) and 6/34 (17.6%) and 7/31 (22.6%) patients, respectively. According to BLISS-LN criteria, responders at 6th and 12th months were 9/34 (26.5%) and 10/31 (32.3%) patients, respectively. CONCLUSIONS: CR and responder status were reached in less than one third of LN patients treated with RTX, regardless of the criteria used to define them. However, serum creatinine levels did not increase, and there was a decrease in proteinuria levels during the follow-up.

Multi-year analysis of the global preclinical antibacterial pipeline: trends and gaps.

Antimicrobial resistance (AMR) is a major global health threat estimated to have caused the deaths of 1.27 million people in 2019, which is more than HIV/AIDS and malaria deaths combined. AMR also has significant consequences on the global economy. If not properly addressed, AMR could immensely impact the world's economy, further increasing the poverty burden in low- and middle-income countries. To mitigate the risk of a post-antibiotic society, where the ability to effectively treat common bacterial infections is being severely threatened, it is necessary to establish a continuous supply of new and novel antibacterial medicines. However, there are gaps in the current pipeline that will prove difficult to address, given the time required to develop new agents. To understand the status of upstream antibiotic development and the challenges faced by drug developers in the early development stage, the World Health Organization has regularly assessed the preclinical and clinical antibacterial development pipeline. The review identifies potential new classes of antibiotics or novel mechanisms of action that can better address resistant bacterial strains. This proactive approach is necessary to stay ahead of evolving resistance patterns and to support the availability of effective treatment options. This review examines the trends in preclinical development and attempts to identify gaps and potential opportunities to overcome the numerous hurdles in the early stages of the antibacterial research and development space.

Identification of Potential Factors Associated with Cellulitis Following Lymphovenous Bypass Surgery in Breast Cancer Survivors.

BACKGROUND: Breast cancer is one of the most common types of cancer, with around 2.3 million cases diagnosed in 2020. One in five cancer patients develops chronic lymphedema caused by multifactorial triggers and treatment-related factors. This can lead to swelling, skin infections, and limb dysfunction, negatively affecting the patient's quality of life. This retrospective cohort study aimed to determine the associations between demographic and breast cancer characteristics and postoperative cellulitis in breast cancer survivors who underwent lymphovenous bypass surgery (LVB) at Mayo Clinic, Florida. METHODS: We performed a retrospective chart review. Data were collected retrospectively from 2016 to 2022. Sixty adult breast cancer survivors who underwent LVB were included in the final analysis based on specific inclusion and exclusion criteria. Patients were excluded if they did not meet the inclusion criteria or had incomplete follow-up data. Demographic and surgical data were extracted, including body mass index (BMI), type of anastomosis, number of anastomoses, and preoperative cellulitis status. Lymphedema measurements were performed using tape measurements. Fisher's exact test was used to determine statistically significant associations between variables and postoperative cellulitis. RESULTS: Postoperative cellulitis was more common in patients aged 60 to 69 years (43.2%), whites (75.0%), overweight or obese (90.9%), with one to four anastomoses (81.8%), and nonsmokers (79.5%). The mean International Society of Lymphology (ISL) criteria for both postoperative cellulitis and no postoperative cellulitis was 1.93. Statistically significant associations with postoperative cellulitis were found for the number of anastomoses (p = 0.021), smoking status (p = 0.049), preoperative cellulitis (p = 0.04), and the length of years with lymphedema diagnosis variable (p = 0.004). CONCLUSION: Our results suggest that a greater number of anastomoses, smoking, preoperative cellulitis, and years with lymphedema are significantly associated with an increased risk of postoperative cellulitis. Awareness of these risk factors is crucial for monitoring and early treatment of infections following surgery.

Prevalence of the Cefazolin Inoculum Effect (CzIE) in Nasal Colonizing Methicillin-Susceptible Staphylococcus aureus in Patients from Intensive Care Units in Colombia and Use of a Modified Rapid Nitrocefin Test for Detection.

The cefazolin inoculum effect (CzIE) has been associated with poor clinical outcomes in patients with MSSA infections. We aimed to investigate the point prevalence of the CzIE among nasal colonizing MSSA isolates from ICU patients in a multicenter study in Colombia (2019-2023). Patients underwent nasal swabs to assess for S. aureus colonization on admission to the ICU and some individuals had follow-up swabs. We performed cefazolin MIC by broth-microdilution using standard and high-inoculum and developed a modified nitrocefin-based rapid test to detect the CzIE. Whole genome sequencing was carried out to characterize BlaZ types and allotypes, phylogenomics and Agr-typing. All swabs were subjected to 16S-rRNA metabarcoding sequencing to evaluate microbiome characteristics associated with the CzIE. A total of 352 patients were included; 46/352 (13%) patients were colonized with S. aureus ; 22% (10/46) and 78% (36/46) with MRSA and MSSA, respectively. Among 36 patients that contributed with 43 MSSA colonizing isolates, 21/36 (58%) had MSSA exhibiting the CzIE. BlaZ type A and BlaZ-2 were the predominant type and allotype in 56% and 52%, respectively. MSSA belonging to CC30 were highly associated with the CzIE and SNP analyses supported transmission of MSSA exhibiting the CzIE among some patients of the same unit. The modified nitrocefin rapid test had 100%, 94.4% and 97.7% sensitivity, specificity and accuracy, respectively. We found a high prevalence point prevalence of the CzIE in MSSA colonizing the nares of critically-ill patients in Colombia. A modified rapid test was highly accurate in detecting the CzIE in this patient population.

Dissecting the structural and functional consequences of the evolutionary proline-glycine deletion in the wing 1 region of the forkhead domain of human FoxP1.

The human FoxP transcription factors dimerize via three-dimensional domain swapping, a unique feature among the human Fox family, as result of evolutionary sequence adaptations in the forkhead domain. This is the case for the conserved glycine and proline residues in the wing 1 region, which are absent in FoxP proteins but present in most of the Fox family. In this work, we engineered both glycine (G) and proline-glycine (PG) insertion mutants to evaluate the deletion events in FoxP proteins in their dimerization, stability, flexibility, and DNA-binding ability. We show that the PG insertion only increases protein stability, whereas the single glycine insertion decreases the association rate and protein stability and promotes affinity to the DNA ligand.

pH-Induced conversion of bolaamphiphilic vesicles to reduction-responsive nanogels for enhanced Nile Red and Rose Bengal delivery.

This study details the preparation and investigation of molecular nanogels formed by the self-assembly of bolaamphiphilic dipeptide derivatives containing a reduction-sensitive disulfide unit. The described bolaamphiphiles, featuring amino acid terminal groups, generate cationic vesicles at pH 4, which evolve into gel-like nanoparticles at pH 7. The critical aggregation concentration has been determined, and the nanogels' size and morphology have been characterized through Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Circular Dichroism (CD) spectroscopy reveals substantial molecular reconfigurations accompanying the pH shift. These nanogels enhance the in vitro cellular uptake of the lipophilic dye Nile Red and the ionic photosensitizer Rose Bengal into Human colon adenocarcinoma (HT-29) cells, eliminating the need for organic co-solvents in the former case. Fluorescence measurements with Nile Red as a probe indicate the reduction-sensitive disassembly of the nanogels. In photodynamic therapy (PDT) applications, Rose Bengal-loaded nanogels demonstrate notable improvements, with flow cytometry analysis evidencing increased apoptotic activity in the study with HT-29 cells.

Changes in retinal nerve fiber layer, ganglion cell complex, and ganglion cell layer thickness in thyroid eye disease: A systematic review.

Thyroid eye disease (TED) is characterized by progressive orbital inflammation. In severe cases, it can lead to dysthyroid optic neuropathy (DON), involving death of retinal ganglion cells and permanent vision loss. Imaging with optical coherence tomography (OCT) has enabled noninvasive examination of the structural impact of the disease, including of the retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL), and the inner plexiform layer (IPL). In this study, we systematically review 20 studies (897 patients, 1430 eyes) to evaluate changes in retinal thickness in patients with TED, stratified by severity. Most studies found a decrease in thickness in peripapillary RNFL (pRNFL), non-pRNFL, combined RNFL/GCL/IPL, or combined GCL/IPL when comparing patients with DON to healthy controls or to patients without DON. However, results were equivocal regarding differences between non-DON TED patients and controls. In addition, several studies reported a postoperative decrease in pRNFL thickness after orbital decompression surgery. Future studies examining OCT changes of retinal thickness along with disease progression are needed to assess the potential of OCT in diagnosis and management of patients with TED.

Clinical correlates of anxious depression in youth from the Texas Youth Depression and Suicide Research Network (TX-YDSRN).

BACKGROUND: Anxious depression is a prevalent subtype of depression associated with adverse outcomes such as higher depression severity and higher rates of suicidality. This study leveraged a state-wide research registry of depressed and/or suicidal youth to compare the prevalence, clinical correlates, and symptom patterns of those with versus without anxious depression. METHODS: We included baseline data from 797 participants (ages 8-20) with a diagnosis of a depressive disorder. A score on the Generalized Anxiety Disorder Scale (GAD-7) ≥ 10 was used to define individuals with and without anxious depression. A structured battery was used to capture psychiatric diagnostic status, depression/anxiety severity, suicide risk, history of trauma, functioning, and resilience. RESULTS: The prevalence of anxious depression among youth with depressive disorders was 59.5 % (n = 474). Youth with anxious depression had greater depression severity and anxiety symptoms, higher suicidality, and a higher prevalence of comorbid anxiety disorders than those without. Youth with anxious depression had greater impairment in functioning defined as worse pain interference, pain severity, fatigue, and social relationships compared to those without anxious depression. Youth with anxious depression also reported higher rates of depressive symptoms such as irritable mood, feelings of guilt, and psychomotor agitation compared to those without anxious depression. CONCLUSION: Anxious depression is associated with worse depression severity, higher suicidality, and lower functioning. Longitudinal work is needed to examine long-term courses of anxious depression to explore its stability as a diagnostic subcategory.

Effect of emerging pollutants on the gut microbiota of freshwater animals: Focusing on microplastics and pesticides.

In recent years, emerging environmental pollutants have increasingly endangered the health of freshwater organisms. The gut microbiota exhibits sensitivity to medications, dietary factors and environmental pollutants, rendering it a novel target for toxicological studies. The gut microbiota can be a potential exposure route affecting the host's health. Herein, we review the current knowledge on two different but concurrent pollutants, microplastics and pesticides, regarding their impact on the gut microbiota, which includes alterations in microbial composition, gene expression, function, and health effects in the hosts. Moreover, synergetic interactions between microplastics and pesticides can exacerbate dysbiosis and health risks. We discuss health-related implications of gut microbial changes based on the consequences in metabolism, immunity, and physiology function. Further research is needed to discover the mechanisms underlying these effects and develop strategies for mitigating their harmful impacts on freshwater animals.

Effects of anther-stigma position on cross-pollination efficiency in a hermaphroditic plant.

PREMISE: Evolution of cross-pollination efficiency depends on the genetic variation of flower traits, the pollen vector, and flower trait matching between pollen donors and recipients. Trait matching has been almost unexplored among nonheterostylous species, and we examined whether the match of anther length in pollen donors and stigma length in pollen recipients influences the efficiency of cross-pollination. To explore potential constraints for evolutionary response, we also quantified genetic variation and covariation among sepal length, petal length and width, stamen length, style length, and herkogamy. METHODS: We created 58 experimental arrays of Turnera velutina that varied in the extent of mismatch in the position of anthers and stigmas between single-flowered plants. Genetic variation and correlations among flower traits were estimated under greenhouse conditions. RESULTS: Style length, but not herkogamy, influenced the efficiency of cross-pollination. Plants with stamen length that matched the style length of other plants were more efficient pollen donors, whereas those with the style protruding above the stamens of other plants were more efficient pollen recipients. Significant broad-sense heritability (0.22 > hB 2 < 0.42) and moderate genetic correlations (0.33 > r < 0.85) among floral traits were detected. CONCLUSIONS: Our results demonstrated that anther-stigma mismatch between flowers contributed to variation in the efficiency of cross-pollination. The genetic correlations between stamen length and other floral traits suggests that any change in cross-pollination efficiency would be driven by changes in style rather than in stamen length.

The complex nature of CXCR4 mutations in WHIM syndrome.

Heterozygous autosomal dominant mutations in the CXCR4 gene cause WHIM syndrome, a severe combined immunodeficiency disorder. The mutations primarily affect the C-terminal region of the CXCR4 chemokine receptor, specifically several potential phosphorylation sites critical for agonist (CXCL12)-mediated receptor internalization and desensitization. Mutant receptors have a prolonged residence time on the cell surface, leading to hyperactive signaling that is responsible for some of the symptoms of WHIM syndrome. Recent studies have shown that the situation is more complex than originally thought, as mutant WHIM receptors and CXCR4 exhibit different dynamics at the cell membrane, which also influences their respective cellular functions. This review examines the functional mechanisms of CXCR4 and the impact of WHIM mutations in both physiological and pathological conditions.

Cefiderocol heteroresistance associated with mutations in TonB-dependent receptor genes in Pseudomonas aeruginosa of clinical origin.

The siderophore-cephalosporin cefiderocol (FDC) presents a promising treatment option for carbapenem-resistant (CR) P. aeruginosa (PA). FDC circumvents traditional porin and efflux-mediated resistance by utilizing TonB-dependent receptors (TBDRs) to access the periplasmic space. Emerging FDC resistance has been associated with loss of function mutations within TBDR genes or the regulatory genes controlling TBDR expression. Further, difficulties with antimicrobial susceptibility testing (AST) and unexpected negative clinical treatment outcomes have prompted concerns for heteroresistance, where a single lineage isolate contains resistant subpopulations not detectable by standard AST. This study aimed to evaluate the prevalence of TBDR mutations among clinical isolates of P. aeruginosa and the phenotypic effect on FDC susceptibility and heteroresistance. We evaluated the sequence of pirR, pirS, pirA, piuA, or piuD from 498 unique isolates collected before the introduction of FDC from four clinical sites in Portland, OR (1), Houston, TX (2), and Santiago, Chile (1). At some clinical sites, TBDR mutations were seen in up to 25% of isolates, and insertion, deletion, or frameshift mutations were predicted to impair protein function were seen in 3% of all isolates (n = 15). Using population analysis profile testing, we found that P. aeruginosa with major TBDR mutations were enriched for a heteroresistant phenotype and undergo a shift in the susceptibility distribution of the population as compared to susceptible strains with wild-type TBDR genes. Our results indicate that mutations in TBDR genes predate the clinical introduction of FDC, and these mutations may predispose to the emergence of FDC resistance.

Additive manufacturing of bioactive and biodegradable poly (lactic acid)-tricalcium phosphate scaffolds modified with zinc oxide for guided bone tissue repair.

Bioactive and biodegradable scaffolds that mimic the natural extracellular matrix of bone serve as temporary structures to guide new bone tissue growth. In this study, 3D-printed scaffolds composed of poly (lactic acid) (PLA)-tricalcium phosphate (TCP) (90-10 wt.%) were modified with 1%, 5%, and 10 wt.% of ZnO to enhance bone tissue regeneration. A commercial chain extender named Joncryl was incorporated alongside ZnO to ensure the printability of the composites. Filaments were manufactured using a twin-screw extruder and subsequently used to print 3D scaffolds via fused filament fabrication (FFF). The scaffolds exhibited a homogeneous distribution of ZnO and TCP particles, a reproducible structure with 300 µm pores, and mechanical properties suitable for bone tissue engineering, with an elastic modulus around 100 MPa. The addition of ZnO resulted in enhanced surface roughness on the scaffolds, particularly for ZnO microparticles, achieving values up to 241 nm. This rougher topography was responsible for enhancing protein adsorption on the scaffolds, with an increase of up to 85% compared to the PLA-TCP matrix. Biological analyses demonstrated that the presence of ZnO promotes mesenchymal stem cell (MSC) proliferation and differentiation into osteoblasts. Alkaline phosphatase (ALP) activity, an important indicator of early osteogenic differentiation, increased up to 29%. The PLA-TCP composite containing 5% ZnO microparticles exhibited an optimized degradation rate and enhanced bioactivity, indicating its promising potential for bone repair applications.

Early- and Late-Onset Alzheimer's Disease: Two Sides of the Same Coin?

Early-onset Alzheimer's disease (EOAD), defined as Alzheimer's disease onset before 65 years of age, has been significantly less studied than the "classic" late-onset form (LOAD), although EOAD often presents with a more aggressive disease course, caused by variants in the APP, PSEN1, and PSEN2 genes. EOAD has significant differences from LOAD, including encompassing diverse phenotypic manifestations, increased genetic predisposition, and variations in neuropathological burden and distribution. Phenotypically, EOAD can be manifested with non-amnestic variants, sparing the hippocampi with increased tau burden. The aim of this article is to review the different genetic bases, risk factors, pathological mechanisms, and diagnostic approaches between EOAD and LOAD and to suggest steps to further our understanding. The comprehension of the monogenic form of the disease can provide valuable insights that may serve as a roadmap for understanding the common form of the disease.

Large Language Models for Intraoperative Decision Support in Plastic Surgery: A Comparison between ChatGPT-4 and Gemini.

Background and Objectives: Large language models (LLMs) are emerging as valuable tools in plastic surgery, potentially reducing surgeons' cognitive loads and improving patients' outcomes. This study aimed to assess and compare the current state of the two most common and readily available LLMs, Open AI's ChatGPT-4 and Google's Gemini Pro (1.0 Pro), in providing intraoperative decision support in plastic and reconstructive surgery procedures. Materials and Methods: We presented each LLM with 32 independent intraoperative scenarios spanning 5 procedures. We utilized a 5-point and a 3-point Likert scale for medical accuracy and relevance, respectively. We determined the readability of the responses using the Flesch-Kincaid Grade Level (FKGL) and Flesch Reading Ease (FRE) score. Additionally, we measured the models' response time. We compared the performance using the Mann-Whitney U test and Student's t-test. Results: ChatGPT-4 significantly outperformed Gemini in providing accurate (3.59 ± 0.84 vs. 3.13 ± 0.83, p-value = 0.022) and relevant (2.28 ± 0.77 vs. 1.88 ± 0.83, p-value = 0.032) responses. Alternatively, Gemini provided more concise and readable responses, with an average FKGL (12.80 ± 1.56) significantly lower than ChatGPT-4's (15.00 ± 1.89) (p < 0.0001). However, there was no difference in the FRE scores (p = 0.174). Moreover, Gemini's average response time was significantly faster (8.15 ± 1.42 s) than ChatGPT'-4's (13.70 ± 2.87 s) (p < 0.0001). Conclusions: Although ChatGPT-4 provided more accurate and relevant responses, both models demonstrated potential as intraoperative tools. Nevertheless, their performance inconsistency across the different procedures underscores the need for further training and optimization to ensure their reliability as intraoperative decision-support tools.

Comparative Analysis of Large Language Models in Emergency Plastic Surgery Decision-Making: The Role of Physical Exam Data.

In the U.S., diagnostic errors are common across various healthcare settings due to factors like complex procedures and multiple healthcare providers, often exacerbated by inadequate initial evaluations. This study explores the role of Large Language Models (LLMs), specifically OpenAI's ChatGPT-4 and Google Gemini, in improving emergency decision-making in plastic and reconstructive surgery by evaluating their effectiveness both with and without physical examination data. Thirty medical vignettes covering emergency conditions such as fractures and nerve injuries were used to assess the diagnostic and management responses of the models. These responses were evaluated by medical professionals against established clinical guidelines, using statistical analyses including the Wilcoxon rank-sum test. Results showed that ChatGPT-4 consistently outperformed Gemini in both diagnosis and management, irrespective of the presence of physical examination data, though no significant differences were noted within each model's performance across different data scenarios. Conclusively, while ChatGPT-4 demonstrates superior accuracy and management capabilities, the addition of physical examination data, though enhancing response detail, did not significantly surpass traditional medical resources. This underscores the utility of AI in supporting clinical decision-making, particularly in scenarios with limited data, suggesting its role as a complement to, rather than a replacement for, comprehensive clinical evaluation and expertise.

Characterization and Seasonal Dynamics of Tick Populations in Dairy Cattle Production Systems of Northwestern Colombian Amazon.

Cattle ticks are a significant health concern in tropical livestock production due to their hematophagous behavior and potential as vectors for human and animal pathogens. In this study, we investigated the tick population present in dairy cattle production, calves, and grazing areas of livestock systems in the northwestern Colombian Amazon. Identification was based on taxonomic keys and molecular markers. Phylogenetic relationships were established using mitochondrial COX1 and 16S genes. Population structure analysis was performed considering age, racial type (B. indicus vs. B. taurus), and the influence of environmental factors and the geomorphological landscape on tick population dynamics. Our findings revealed the presence of a single tick species, with a unique haplotype identified for each mitochondrial gene assessed. Phylogenetic analysis classified the found species within Clade A of the Rhipicephalus microplus complex. Ticks were more prevalent during periods of low rainfall and high temperature, and B. taurus cows exhibited the highest tick abundance. Thus, these results provide insights into the population characteristics and distribution of the tick species present in dairy cattle production systems in the northwestern part of the Colombian Amazon. This information is fundamental for developing targeted strategies based on seasonal variation and host characteristics to mitigate tick infestation severity in the region.

Periodontal status and mandibular biomechanics in rats subjected to hyposalivation and periodontitis.

Xerostomia emerges as a consequence of salivary gland hypofunction, and seriously compromises the integrity of hard and soft oral tissues, whileperiodontitis is an infectious disease characterized by biofilm accumulation, inflammation and alveolar bone resorption. AIM: The aim this study was to compare the deleterious effects caused by experimental hyposalivation, periodontitis, and the combination of both on periodontal tissues and mandibular biomechanics in rats. MATERIALS AND METHOD: Hyposalivation (group H) was induced through bilateral submandibulectomy. Periodontitis (group EP) was induced by injecting LPS (1 mg/ml) into the gingiva of the first lower molars. A third group was subjected to both conditions (group H+EP). Alveolar bone loss was evaluated by micro-computed tomography and histomorphometric analysis, and gingival inflammatory mediators were assessed by specific techniques. Biomechanical properties were evaluated in mandible. RESULTS: Alveolar bone loss increased similarly in groups H, EP and H+EP compared to control. Metalloproteinase (MMP2 and MMP9) activity was similar in H and control, but higher in groups EP and H+EP (MMP2: C 9644+2214, EP 34441+3336, H 5818+1532, H+EP 42673+3184; MMP9: C 5792+961, EP 14807+861, H 9295+520, H+EP 4838+1531). The rest of the inflammatory mediators evaluated increased in groups H, EP and H+EP to a greater or lesser extent with respect to the control, although in most cases, they were higher in groups EP and H+EP than in group H. The biomechanical properties of the mandible increased in group H compared to the other three groups. CONCLUSIONS: Both hyposalivation and periodontitis cause periodontal damage, but hyposalivation also produces biomechanical alterations, causing more extensive deleterious effects than periodontitis.

La xerostomía surge como consecuencia de la hipofunción de las glándulas salivales y compromete seriamente la integridad de los tejidos orales duros y blandos, mientras que la periodontitis es una enfermedad infecciosa caracterizada por la acumulación de biofilm, inflamación y reabsorción ósea alveolar. OBJETIVO: El objetivo del presente estudio fue comparar los efectos deletéreos causados por la hiposalivación y la periodontitis experimental, y la combinación de ambas sobre los tejidos periodontales y la biomecánica mandibular en ratas. MATERIALES Y MÉTODOS: La hiposalivación (H) se indujo mediante una submandibulectomía bilateral. Por otra parte, la periodontitis (PE) se indujo mediante la inyección de LPS (1 mg/ml) en la encía de los primeros molares inferiores. Otro grupo se sometió a ambas condiciones (H+PE). La pérdida ósea alveolar se evaluó mediante tomografia microcomputarizada y análisis histomorfométrico, mientras que los mediadores inflamatorios gingivales fueron determinados mediante técnicas específicas. Se evaluaron las propiedades biomecánicas en la mandíbula. RESULTADOS: La hiposalivación aumentó la pérdida ósea alveolar en comparación con el control de forma similar a la PE y H+PE. La actividad de las metaloproteinasas (MMP2 y MMP9) fue similar en los grupos H y control, pero resultó mayor en los grupos PE y H+PE (MMP2: C 9644+2214, PE 34441+3336, H 5818+1532, H+PE 42673+3184; MMP9: C 5792+961, PE 14807+861, H 9295+520, H+PE 24838+1531). El resto de los mediadores inflamatorios evaluados aumentaron en mayor o menor medida en los grupos H, PE y H+PE respecto al control, aunque en la mayoría de los casos fueron superiores en los grupos PE y H+PE respecto al grupo H. Sin embargo, las propiedades biomecánicas de la mandíbula aumentaron en el grupo H con respecto a los otros grupos. CONCLUSIONES: Tanto la hiposalivación como la periodontitis causan daño periodontal, pero la hiposalivación también produce alteraciones biomecánicas, provocando efectos deletéreos más extensos que la periodontitis.