Assessment of the Cutaneous Hormone Landscapes and Microbiomes in Vulvar Lichen Sclerosus

Vulvar lichen sclerosus (VLS) is a progressive skin disease of unknown etiology. In this longitudinal case-control exploratory study, we evaluated the hormonal and microbial landscapes in 18 postmenopausal women (mean [SD] age: 64.4 [8.4]) with vulvar lichen sclerosus and controls. We reevaluated the VLS patients after 10-14 weeks of daily topical Class I steroid. We found that groin cutaneous estrone was lower in vulvar lichen sclerosus versus controls (-22.33, 95% CI -36.96 to -7.70; P = 0.006); cutaneous progesterone was higher (5.73, 95% CI 3.74 to 7.73; P< 0.0001). Forehead 11-deoxycortisol (-0.24, 95% CI -0.42 to -0.06; P = 0.01) and testosterone (-7.22, 95% CI -12.83 to -1.62; P = 0.02) were lower in disease. With treatment, cutaneous estrone (-7.88, 95% CI -44.07 to 28.31; P = 0.62), progesterone (2.02, 95% CI -2.08 to 6.11; P = 0.29), and 11-deoxycortisol (-0.13, 95% CI -0.32 to 0.05; P = 0.15) normalized; testosterone remained suppressed (-7.41, 95% CI -13.38 to -1.43; P = 0.02). 16S rRNA V1-V3 and ITS1 amplicon sequencing revealed bacterial and fungal microbiome alterations in disease. Findings suggest that cutaneous sex hormone and bacterial microbiome alterations may be associated with VLS in postmenopausal women.

Consequences of depleting TNRC6, AGO, and DROSHA proteins on expression of microRNAs

The potential for microRNAs (miRNAs) to regulate gene expression remains incompletely understood. DROSHA initiates the biogenesis of miRNAs while variants of Argonaute (AGO) and Trinucleotide Repeat Containing Six (TNRC6) family proteins form complexes with miRNAs to facilitate RNA recognition and gene regulation. Here we investigate the fate of miRNAs in the absence of these critical RNAi protein factors. Knockout of DROSHA expression reduces levels of some miRNAs annotated in miRbase but not others. The identity of miRNAs with reduced expression matches the identity of miRNAs previously identified by experimental approaches. The miRgeneDB resource offers closest alignment with experimental results. By contrast, the loss of TNRC6 proteins had much smaller effects on miRNA levels. Knocking out AGO proteins, which directly contact the mature miRNA, decreased expression of the miRNAs most strongly associated with AGO2 as determined from enhanced crosslinking immunoprecipitation (AGO2-eCLIP). Evaluation of miRNA binding to endogenously-expressed AGO proteins revealed that miRNA:AGO association was similar for AGO1, AGO2, AGO3, and AGO4. Our data emphasize the need to evaluate annotated miRNAs based on approximate cellular abundance, DROSHA dependence, and physical association with AGO when forming hypotheses related to their function.

Saprophytic bacteria and fungi colonize stearoyl coenzyme-A desaturase-1 knockout skin

Lipids synthesized on the skin are critical to the antimicrobial barrier. Skin lipids also facilitate survival of lipophilic skin commensals in an otherwise dry and acidic ecological landscape. Thus, skin-specific stearoyl-coenzyme A desaturase 1 knockout mice (Scd1^ΔK14 ) with sebocyte atrophy and decreased synthesis of monounsaturated fatty acids, triglycerides and wax diesters have dry, inflamed skin. Here, we used 16S rRNA (V1-V2 and V1-V9) and internal transcribed spacer 1 (ITS1) amplicon sequencing to compare bacterial and fungal skin microbiomes between Scd1^ΔK14 mice and wildtype control mice (Scd1^fl/fl ) in a barrier facility. Saprophytic bacteria including Sporosarcina spp. and Staphylococcus lentus and saprophytic fungi including Alternaria infectoria were found in higher relative abundance in the Scd1^ΔK14 group (ANCOM). Analysis of community diversity (Shannon index) revealed greater fungal alpha diversity in the Scd1^ΔK14 group (p = 0.009, Kruskal-Wallis). Principal coordinates analysis (Bray-Curtis dissimilarity) showed that both bacterial (p = 0.002, PERMANOVA) and fungal communities (p = 0.006, PERMANOVA) of the Scd1^ΔK14 group were unique from the wildtype group. Altogether, these results suggest that sebaceous gland-derived lipids normally restrict the skin microbiome, and in the absence of these lipids, a greater diversity of opportunistic organisms are able to colonize the surface of skin.

Ectopic JAK–STAT activation enables the transition to a stem-like and multilineage state conferring AR-targeted therapy resistance

Emerging evidence indicates that various cancers can gain resistance to targeted therapies by acquiring lineage plasticity. Although various genomic and transcriptomic aberrations correlate with lineage plasticity, the molecular mechanisms enabling the acquisition of lineage plasticity have not been fully elucidated. We reveal that Janus kinase (JAK)–signal transducer and activator of transcription (STAT) signaling is a crucial executor in promoting lineage plasticity-driven androgen receptor (AR)-targeted therapy resistance in prostate cancer. Importantly, ectopic JAK–STAT activation is specifically required for the resistance of stem-like subclones expressing multilineage transcriptional programs but not subclones exclusively expressing the neuroendocrine-like lineage program. Both genetic and pharmaceutical inhibition of JAK–STAT signaling resensitizes resistant tumors to AR-targeted therapy. Together, these results suggest that JAK–STAT are compelling therapeutic targets for overcoming lineage plasticity-driven AR-targeted therapy resistance.

A short plus long-amplicon based sequencing approach improves genomic coverage and variant detection in the SARS-CoV-2 genome

High viral transmission in the COVID-19 pandemic has enabled SARS-CoV-2 to acquire new mutations that may impact genome sequencing methods. The ARTIC.v3 primer pool that amplifies short amplicons in a multiplex-PCR reaction is one of the most widely used methods for sequencing the SARS-CoV-2 genome. We observed that some genomic intervals are poorly captured with ARTIC primers. To improve the genomic coverage and variant detection across these intervals, we designed long amplicon primers and evaluated the performance of a short (ARTIC) plus long amplicon (MRL) sequencing approach. Sequencing assays were optimized on VR-1986D-ATCC RNA followed by sequencing of nasopharyngeal swab specimens from fifteen COVID-19 positive patients. ARTIC data covered 94.47% of the virus genome fraction in the positive control and patient samples. Variant analysis in the ARTIC data detected 217 mutations, including 209 single nucleotide variants (SNVs) and eight insertions & deletions. On the other hand, long-amplicon data detected 156 mutations, of which 80% were concordant with ARTIC data. Combined analysis of ARTIC + MRL data improved the genomic coverage to 97.03% and identified 214 high confidence mutations. The combined final set of 214 mutations included 203 SNVs, 8 deletions and 3 insertions. Analysis showed 26 SARS-CoV-2 lineage defining mutations including 4 known variants of concern K417N, E484K, N501Y, P618H in spike gene. Hybrid analysis identified 7 nonsynonymous and 5 synonymous mutations across the genome that were either ambiguous or not called in ARTIC data. For example, G172V mutation in the ORF3a protein and A2A mutation in Membrane protein were missed by the ARTIC assay. Thus, we show that while the short amplicon (ARTIC) assay provides good genomic coverage with high throughput, complementation of poorly captured intervals with long amplicon data can significantly improve SARS-CoV-2 genomic coverage and variant detection.

In Obese Patients With Type 2 Diabetes, Mast Cells in Omental Adipose Tissue Decrease the Surface Expression of CD45, CD117, CD203c, and FcϵRI

The paradigm of mast cells in type 2 diabetes is changing. Although they were first considered deleterious inflammatory cells, now they seem to be important players driving adipose tissue homeostasis. Here we have employed a flow cytometry-based approach for measuring the surface expression of 4 proteins (CD45, CD117, CD203c, and FcϵRI) on mast cells of omental (o-WAT) and subcutaneous white adipose tissue (s-WAT) in a cohort of 96 patients with morbid obesity. The cohort was split into three groups: non-T2D, pre-T2D, and T2D. Noteworthy, patients with T2D have a mild condition (HbA1c <7%). In o-WAT, mast cells of patients with T2D have a decrease in the surface expression of CD45 (p=0.0013), CD117 (p=0.0066), CD203c (p=0.0025), and FcϵRI (p=0.043). Besides, in s-WAT, the decrease was seen only in CD117 (p=0.046). These results indicate that T2D affects more to mast cells in o-WAT than in s-WAT. The decrease in these four proteins has serious effects on mast cell function. CD117 is critical for mast cell survival, while CD45 and FcϵRI are important for mast cell activation. Additionally, CD203c is only present on the cell surface after granule release. Taking together these observations, we suggest that mast cells in o-WAT of patients with T2D have a decreased survival, activation capacity, and secretory function.

Impact of Bead-Beating Intensity on the Genus- and Species-Level Characterization of the Gut Microbiome Using Amplicon and Complete 16S rRNA Gene Sequencing

Bead-beating within a DNA extraction protocol is critical for complete microbial cell lysis and accurate assessment of the abundance and composition of the microbiome. While the impact of bead-beating on the recovery of OTUs at the phylum and class level have been studied, its influence on species-level microbiome recovery is not clear. Recent advances in sequencing technology has allowed species-level resolution of the microbiome using full length 16S rRNA gene sequencing instead of smaller amplicons that only capture a few hypervariable regions of the gene. We sequenced the v3-v4 hypervariable region as well as the full length 16S rRNA gene in mouse and human stool samples and discovered major clusters of gut bacteria that exhibit different levels of sensitivity to bead-beating treatment. Full length 16S rRNA gene sequencing unraveled vast species diversity in the mouse and human gut microbiome and enabled characterization of several unclassified OTUs in amplicon data. Many species of major gut commensals such as Bacteroides, Lactobacillus, Blautia, Clostridium, Escherichia, Roseburia, Helicobacter, and Ruminococcus were identified. Interestingly, v3-v4 amplicon data classified about 50% of Ruminococcus reads as Ruminococcus gnavus species which showed maximum abundance in a 9 min beaten sample. However, the remaining 50% of reads could not be assigned to any species. Full length 16S rRNA gene sequencing data showed that the majority of the unclassified reads were Ruminococcus albus species which unlike R. gnavus showed maximum recovery in the unbeaten sample instead. Furthermore, we found that the Blautia hominis and Streptococcus parasanguinis species were differently sensitive to bead-beating treatment than the rest of the species in these genera. Thus, the present study demonstrates species level variations in sensitivity to bead-beating treatment that could only be resolved with full length 16S rRNA sequencing. This study identifies species of common gut commensals and potential pathogens that require minimum (0-1 min) or extensive (4-9 min) bead-beating for their maximal recovery.

In Patients With Obesity, the Number of Adipose Tissue Mast Cells Is Significantly Lower in Subjects With Type 2 Diabetes

Type 2 diabetes (T2D) is a rising global health problem mainly caused by obesity and a sedentary lifestyle. In healthy individuals, white adipose tissue (WAT) has a relevant homeostatic role in glucose metabolism, energy storage, and endocrine signaling. Mast cells contribute to these functions promoting WAT angiogenesis and adipogenesis. In patients with T2D, inflammation dramatically impacts WAT functioning, which results in the recruitment of several leukocytes, including monocytes, that enhance this inflammation. Accordingly, the macrophages population rises as the WAT inflammation increases during the T2D status worsening. Since mast cell progenitors cannot arrive at WAT, the amount of WAT mast cells depends on how the new microenvironment affects progenitor and differentiated mast cells. Here, we employed a flow cytometry-based approach to analyze the number of mast cells from omental white adipose tissue (o-WAT) and subcutaneous white adipose tissue (s-WAT) in a cohort of 100 patients with obesity. Additionally, we measured the number of mast cell progenitors in a subcohort of 15 patients. The cohort was divided in three groups: non-T2D, pre-T2D, and T2D. Importantly, patients with T2D have a mild condition (HbA1c <7%). The number of mast cells and mast cell progenitors was lower in patients with T2D in both o-WAT and s-WAT in comparison to subjects from the pre-T2D and non-T2D groups. In the case of mast cells in o-WAT, there were statistically significant differences between non-T2D and T2D groups (p = 0.0031), together with pre-T2D and T2D groups (p=0.0097). However, in s-WAT, the differences are only between non-T2D and T2D groups (p=0.047). These differences have been obtained with patients with a mild T2D condition. Therefore, little changes in T2D status have a huge impact on the number of mast cells in WAT, especially in o-WAT. Due to the importance of mast cells in WAT physiology, their decrease can reduce the capacity of WAT, especially o-WAT, to store lipids and cause hypoxic cell deaths that will trigger inflammation.

IRF1 governs the differential interferon-stimulated gene responses in human monocytes and macrophages by regulating chromatin accessibility

Myeloid lineage cells use TLRs to recognize and respond to diverse microbial ligands. Although unique transcription factors dictate the outcome of specific TLR signaling, whether lineage-specific differences exist to further modulate the quality of TLR-induced inflammation remains unclear. Comprehensive analysis of global gene transcription in human monocytes, monocyte-derived macrophages, and monocyte-derived dendritic cells stimulated with various TLR ligands identifies multiple lineage-specific, TLR-responsive gene programs. Monocytes are hyperresponsive to TLR7/8 stimulation that correlates with the higher expression of the receptors. While macrophages and monocytes express similar levels of TLR4, macrophages, but not monocytes, upregulate interferon-stimulated genes (ISGs) in response to TLR4 stimulation. We find that TLR4 signaling in macrophages uniquely engages transcription factor IRF1, which facilitates the opening of ISG loci for transcription. This study provides a critical mechanistic basis for lineage-specific TLR responses and uncovers IRF1 as a master regulator for the ISG transcriptional program in human macrophages.

Deep sequencing reveals a DAP1 regulatory haplotype that potentiates autoimmunity in systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is a clinically heterogeneous autoimmune disease characterized by the development of anti-nuclear antibodies. Susceptibility to SLE is multifactorial, with a combination of genetic and environmental risk factors contributing to disease development. Like other polygenic diseases, a significant proportion of estimated SLE heritability is not accounted for by common disease alleles analyzed by SNP array-based GWASs. Death-associated protein 1 (DAP1) was implicated as a candidate gene in a previous familial linkage study of SLE and rheumatoid arthritis, but the association has not been explored further.

RESULTS

We perform deep sequencing across the DAP1 genomic segment in 2032 SLE patients, and healthy controls, and discover a low-frequency functional haplotype strongly associated with SLE risk in multiple ethnicities. We find multiple cis-eQTLs embedded in a risk haplotype that progressively downregulates DAP1 transcription in immune cells. Decreased DAP1 transcription results in reduced DAP1 protein in peripheral blood mononuclear cells, monocytes, and lymphoblastoid cell lines, leading to enhanced autophagic flux in immune cells expressing the DAP1 risk haplotype. Patients with DAP1 risk allele exhibit significantly higher autoantibody titers and altered expression of the immune system, autophagy, and apoptosis pathway transcripts, indicating that the DAP1 risk allele mediates enhanced autophagy, leading to the survival of autoreactive lymphocytes and increased autoantibody.

CONCLUSIONS

We demonstrate how targeted sequencing captures low-frequency functional risk alleles that are missed by SNP array-based studies. SLE patients with the DAP1 genotype have distinct autoantibody and transcription profiles, supporting the dissection of SLE heterogeneity by genetic analysis.

Longitudinal Immune and Genomic Monitoring Reveals Signatures of Immune-related Adverse Events in Cancer Patients Receiving Checkpoint Inhibitor Therapy

Despite the remarkable success of immune checkpoint inhibitor (ICI) therapy, a significant number of patients develop severe and unpredictable immune-related adverse events (irAEs) affecting a wide variety of organs. Concerns over irAE have led to the exclusion of patients with autoimmune disease from ICI clinical trials. Role of host genetic and immune factors in mediating irAEs remain unclear and it is not clear if the manifestations of irAEs is associated with response to therapy. Here, we use multi-faceted approach to characterize changes in host immune system in 200 patients receiving ICI therapy at baseline and post immunotherapy. In addition, we assessed genetic predisposition to autoimmunity using the Illumina SNP array and via targeted resequencing of over 150 immunoregulatory loci including the HLA region. In this meeting, we will present our initial genetic data, serum cytokine and autoantibody profiles and RNA sequencing on peripheral blood mononuclear cells (PBMCs) at baseline and post immunotherapy in patients with and without irAEs. Our preliminary findings suggest that patients who developed irAEs have lower baseline levels and greater post-treatment increases in key interferon gamma inducible cytokine/chemokine levels. Our autoantibody profiling data reveals unique sets of autoantibodies associated with specific irAEs. We will present a comprehensive analysis of immune and genetic correlates of irAEs and response to therapy. We hope our study can help gain insight in to the mechanisms underlying irAE and to identify biomarker signatures predictive of irAEs and/or response. These findings may ultimately help identify high-risk patients, customize therapy, expand use of immunotherapy and prevent toxicities.

Chromatin accessibility modulates the induction of innate immunity in cells of myeloid lineage

The Toll-like receptors (TLRs) of the innate immune system play a key role in the recognition of pathogens. TLRs signal through the recruitment of specific adaptor molecules, leading to activation of the transcription factors, such as AP-1, NF-κB and interferon regulatory factors (IRFs). Although TLRs are mainly expressed in immune cells, a systematic comparison of immune cells activation programs induced by specific individual TLRs is not yet available. Here, we used whole transcriptome sequencing to evaluate global changes in gene expression on monocytes, monocyte-derived macrophages (MDM) and monocyte-derived dendritic cells (MDDC) of five human donors before and after 18 hours stimulation through the TLR2, TLR4, TLR7 and TLR7/8 agonists (Pam3CSK4, LPS, R837 and R848). Cluster analysis demonstrated eight distinct clusters of unresponsive or responsive genes by the four TLR agonists in monocytes, MDM and MDDC. TLR7/8 stimulation by R848 led to the most robust cytokine and chemokine transcription in all cell types, especially in monocytes. Interestingly, we found that interferon-stimulated genes were strongly induced only by TLR4 activation in MDM and only by TLR7 and TLR8 activation in monocytes. Unexpectedly, there was no difference of activation of MAPK, NF-κB and IRF by LPS or R848 in these cell types. Surprisingly, we revealed that chromatin accessibility is significantly correlated with genes that are induced by specific TLR agonists on specific cell type(s), using ATAC-seq. Therefore, our results suggest in spite of robust early signal transduction events, factor that regulate chromatin accessibility play a critical role in regulation of inflammatory gene expression by TLR agonists in cells of the innate immune system.

Increased salivary oxidative stress parameters in patients with type 2 diabetes: Relation with periodontal disease

OBJECTIVE

The aim of this study was to determine whether there are differences in salivary oxidative stress between patients with diabetes mellitus type 2 (DM2) and healthy non-diabetic patients, and whether this oxidative stress is associated with the presence of periodontal disease in diabetic patients.

MATERIAL AND METHODS

This observational study included 70 patients divided into three groups according to metabolic control levels: 19 non-diabetic patients (control group); 24 patients with good metabolic control (HbA1c<7%), and 27 patients DM2 with poor metabolic control (HbA1c>7%). The following oxidative stress parameters were measured in all subjects: glutathione peroxidase (GPx), glutathione reductase (GRd), reduced glutathione (GSH) and oxidized glutathione (GSSG). Periodontal health was determined by means of the community periodontal index (CPI) recommended by the WHO.

RESULTS

The diabetic group with good metabolic control showed a significant increase in GPx and GRd activity in comparison with the control group (P<.001). The activity of the enzymes measured was significantly less in patients with poor metabolic control in comparison with the control group and well-controlled diabetic groups (P<.001). Both diabetic groups showed higher GSSG/GSH quotients and CPI in comparison with the control group, and both parameters were significantly higher in diabetic patients with poor metabolic control in comparison with well-controlled diabetic patients.

CONCLUSIONS

Poor metabolic control in DM2 patients is associated with higher levels of salivary oxidative stress and worse periodontal health.

Antibiotic-Induced Depletion of Anti-inflammatory Clostridia Is Associated with the Development of Graft-versus-Host Disease in Pediatric Stem Cell Transplantation Patients

Adult stem cell transplantation (SCT) patients with graft-versus-host-disease (GVHD) exhibit significant disruptions in gut microbial communities. These changes are associated with higher overall mortality and appear to be driven by specific antibiotic therapies. It is unclear whether pediatric SCT patients who develop GVHD exhibit similar antibiotic-induced gut microbiota community changes. Here, we show that pediatric SCT patients (from Children's Medical Center Dallas, n = 8, and Cincinnati Children's Hospital, n = 7) who developed GVHD showed a significant decline, up to 10-log fold, in gut anti-inflammatory Clostridia (AIC) compared with those without GVHD. In fact, the development of GVHD is significantly associated with this AIC decline and with cumulative antibiotic exposure, particularly antibiotics effective against anaerobic bacteria (P = .003, Firth logistic regression analysis). Using metagenomic shotgun sequencing analysis, we were able to identify specific commensal bacterial species, including AIC, that were significantly depleted in GVHD patients. We then used a preclinical GVHD model to verify our clinical observations. Clindamycin depleted AIC and exacerbated GVHD in mice, whereas oral AIC supplementation increased gut AIC levels and mitigated GVHD in mice. Together, these data suggest that an antibiotic-induced AIC depletion in the gut microbiota is associated with the development of GVHD in pediatric SCT patients.

Hereditary Blood Coagulation Disorders: Management and Dental Treatment

Patients with hereditary hemostatic disorders, characterized by a tendency to bleeding or thrombosis, constitute a serious challenge in the dental practice. Advances in the medical diagnosis of hemostatic disorders have exposed dental professionals to new patients not amenable to the application of the management protocols associated with other, more well-known, disorders. It is the aim of this paper to review the evidence, to highlight the areas of major concern, and to suggest management regimens for patients with hereditary hemostatic disorders. An extensive review has been made (PubMed, Science Direct, Web of Knowledge, etc.) of literature pertaining to hereditary disorders affecting blood coagulation factors and how they affect the practice of dentistry. Several aspects relating to the care of such patients must be recognized and taken into consideration when dental treatment is planned. Replacement of deficient coagulation factors ensures that safe dental treatment will be carried out. However, the half-life of such coagulation factors requires that dental treatment be specifically planned and adapted to the type of pathology involved.

Regulatory polymorphisms modulate the expression of HLA class II molecules and promote autoimmunity

Targeted sequencing of sixteen SLE risk loci among 1349 Caucasian cases and controls produced a comprehensive dataset of the variations causing susceptibility to systemic lupus erythematosus (SLE). Two independent disease association signals in the HLA-D region identified two regulatory regions containing 3562 polymorphisms that modified thirty-seven transcription factor binding sites. These extensive functional variations are a new and potent facet of HLA polymorphism. Variations modifying the consensus binding motifs of IRF4 and CTCF in the XL9 regulatory complex modified the transcription of HLA-DRB1, HLA-DQA1 and HLA-DQB1 in a chromosome-specific manner, resulting in a 2.5-fold increase in the surface expression of HLA-DR and DQ molecules on dendritic cells with SLE risk genotypes, which increases to over 4-fold after stimulation. Similar analyses of fifteen other SLE risk loci identified 1206 functional variants tightly linked with disease-associated SNPs and demonstrated that common disease alleles contain multiple causal variants modulating multiple immune system genes.

POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) treated with autologous hematopoietic stem cell transplantation: a case report and literature review

BACKGROUND

POEMS syndrome is a rare systemic pathology of paraneoplastic origin that is associated with plasma cell dyscrasia. It is characterized by the presence of sensorimotor polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes, and other systemic manifestations. The pathogenesis of the syndrome is unknown but over-production of vascular endothelial growth factor is probably responsible for most of the more characteristic symptoms. There is no standard treatment for POEMS syndrome and no randomized controlled clinical trials of treatment exist in the available literature. High-dose melphalan with autologous hematopoietic stem cell transplantation should be considered for younger patients with widespread osteosclerotic lesions, and for patients with rapidly progressive neuropathy.

CASE REPORT

This is the case of a 62-year-old Caucasian man who was admitted to our center presenting pretibial edema accompanied by significant weight loss and difficulty walking. POEMS criteria were present and an immunofixation test confirmed the presence of a monoclonal plasmaproliferative disorder. After autologous hematopoietic stem cell transplantation, the monoclonal component disappeared and the patient's clinical status improved markedly.

CONCLUSIONS

Autologous hematopoietic stem cell transplantation following high-dose melphalan is an effective therapy for younger patients with widespread osteosclerotic lesions in POEMS syndrome.

The effects of growth hormone on the initial bone formation around implants

PURPOSE

The aim of this study was to evaluate the effect of the topical application of growth hormone on the osseointegration of dental implants in beagle dogs 14 days after placement.

MATERIALS AND METHODS

Maxillary and mandibular premolars and molars were extracted from 12 beagle dogs. Two months later, each mandible received cylindric screw-type implants of 3.25 mm in diameter and 10 mm in length. The implants were randomly assigned to the mesial and distal sites on each side of the mandible. Prior to implantation, lyophilized powdered growth hormone was applied to one osteotomy on each side of the mandible. No growth hormone was applied at the control sites. Eight histologic sections per implant were obtained for histomorphometric analysis.

RESULTS

After a 2-week treatment period, the growth hormone-treated sites showed significant (P < .0001) increases in the perimeter of bone that was in direct contact with the treated implants (40.19% +/- 2.51%), total peri-implant area (P < .001) (69.57% +/- 3.53%), and new bone formation (P < .0001) (35.18% +/- 0.31%), in comparison to control implants (25.05% +/- 2.43%, 53.40% +/- 4.58%, and 28.65% +/- 1.92%, respectively). There was no significant increase in interthread bone in growth hormone-treated implants (27.92% +/- 3.31%) in comparison to control implants (25.08% +/- 3.47%) (P > .05).

CONCLUSION

Topical application of growth hormone may act as a bone stimulant in the placement of endosseous dental implants.

Melatonin stimulates osteointegration of dental implants

The aim of this study was to evaluate the effect of the topical application of melatonin on osteointegration of dental implants in Beagle dogs 14 days after their insertion. In preparation for subsequent insertion of dental implants, upper and lower premolars and molars were extracted from 12 Beagle dogs. Each mandible received cylindrical screw implants of 3.25 mm in diameter and 10 mm in length. The implants were randomly assigned to the mesial and distal sites on each side of the mandible. Prior to implanting, 1.2 mg lyophylized powdered melatonin was applied to one bone hole at each side of the mandible. None was applied at the control sites. Eight histological sections per implant were obtained for histomorphometric studies. After a 2-wk treatment period, melatonin significantly increased the perimeter of bone that was in direct contact with the treated implants (P < 0.0001), bone density (P < 0.0001), new bone formation (P < 0.0001) and inter-thread bone (P < 0.05) in comparison with control implants. Topical application of melatonin may act as a biomimetic agent in the placement of endo-osseous dental implants.

Melatonin expression in periodontal disease

BACKGROUND AND OBJECTIVE

It was the purpose of this study to examine the relationship between periodontal diseases and melatonin level.

MATERIAL AND METHODS

Forty-six patients with periodontal disease, together with 26 age- and gender-matched healthy controls, were included. Periodontal status was assessed using the Community Periodontal Index. Plasma and salivary melatonin levels were determined using specific commercial radioimmunoassays, whereas lymphocyte subpopulations (e.g. CD3, CD4, CD8, C19 and natural killer cells) were analyzed using flow cytometry.

RESULTS

Patients with periodontal disease had significantly (p < 0.001) lower plasma (9.46 +/- 3.18 pg/mL) and saliva (2.55 +/- 0.99 pg/mL) melatonin levels than healthy control patients (14.33 +/- 4.05 and 4.22 +/- 0.87 pg/mL, respectively). A biphasic relationship was observed between plasma melatonin levels and Community Periodontal Indices. The plasma melatonin level was reduced in patients with a lower Community Periodontal Index value (1 or 2) and increased in patients with a higher Community Periodontal Index value (3 or 4). Salivary melatonin parallels the changes of plasma melatonin. The higher the Community Periodontal Index, the older the patient and the higher the total lymphocyte counts. CD4 concentrations also increased as the disease worsened.

CONCLUSION

The results obtained from this study suggest that melatonin could act as a protective function in fighting periodontal infection. However, further studies in this area are encouraged.

Melatonin: potential functions in the oral cavity

BACKGROUND

Melatonin is synthesized and secreted by the pineal gland and other organs. The pattern of melatonin secretion is controlled by an endogenous circadian timing system and conveys information about the light-dark cycle to the organism, thereby organizing its seasonal and circadian rhythms. Melatonin has powerful antioxidant effects, functions in an immunomodulatory role, may protect against certain cancers, delays some age-related processes, stimulates the synthesis of type I collagen fibers, and promotes bone formation.

METHODS

An extensive review was made (e.g., using PubMed, Science Direct, and Web of Knowledge) of the literature.

RESULTS

Melatonin, which is released into the saliva, may have important implications for dental disorders, especially in periodontal disease. Diseases of the periodontium are known to be aggravated by free radicals and by alterations in the immune response to microorganisms that are present in plaque. In response to periodontal inflammation, the blood and salivary levels of melatonin may increase.

CONCLUSION

Melatonin may play a role in protecting the oral cavity from tissue damage that is due to oxidative stress, and it may contribute to the regeneration of alveolar bone through the stimulation of type I collagen fiber production and the modulation of osteoblastic and osteoclastic activity.

An in vitro tissue model to study the effect of age on nucleus pulposus cells

Differentiation between age (physiological) and disease-induced changes in the nucleus pulposus will facilitate our understanding of the mechanism(s) leading to the development of degenerative disc disease. The aim of this study was to develop an in vitro model that would allow the study of age-induced alterations of cell function in nucleus pulposus. Nucleus pulposus (NP) cells were isolated from intervertebral discs obtained from either calves (<9 months) or cows (>18 months). The cells were placed in culture and grown for 19 days. Although nucleus pulposus tissue was formed by the cells of the two different ages the more mature (older) cells formed less tissue as determined histologically by light microscopy. This was confirmed biochemically as the wet weight and proteoglycan content of the tissue formed by the older cells were significantly less than that of the younger tissue. The older cells accumulated less proteoglycans as determined by quantifying radioisotope incorporation. The older cells showed lower constitutive gene expression of collagen type II and aggrecan whereas collagen type I and link protein levels were similar to those of the younger cells. Metalloprotease (MMP) 13 gene and protein expression increased with age. There was no change in the levels of gene expression of MMP 2 and TIMP 1, 2, or 3 with age. Cells obtained from NP tissue harvested from younger or mature animals showed both genotypic and phenotypic differences in vitro that resulted in the inability of the older cells to reconstitute their extracellular matrix to the same extent as the younger cells. This suggests that this in vitro NP tissue model will be suitable to determine the mechanism(s) regulating age-induced changes.

Local Application of Melatonin Into Alveolar Sockets of Beagle Dogs Reduces Tooth Removal–Induced Oxidative Stress

BACKGROUND

The antioxidant and anti-inflammatory hormone melatonin is secreted by saliva into the oral cavity, where it may protect the mucosal and gingival tissues from radical damage. To date, no studies have addressed the potential beneficial role of melatonin in the acute inflammatory response that follows oral surgical interventions, especially tooth extractions. The aim of this study was to determine whether tooth extraction induces changes in plasma oxidative stress levels, and whether melatonin treatment may counteract these changes.

METHODS

Maxillary and mandibular premolars and molars of 16 adult Beagle dogs were extracted under general anesthesia. Eight dogs were treated with 2 mg melatonin placed into the alveolar sockets, whereas the other eight dogs received only vehicle. Lipid peroxidation (LPO) and nitrite plus nitrate (NOx) levels were determined in plasma, whereas glutathione (GSH) and glutathione disulfide (GSSG) levels and glutathione peroxidase (GPx) and reductase (GRd) activities were measured in red blood cells before and 24 hours after tooth extraction.

RESULTS

Removal of the premolars and molars caused a significant rise in plasma LPO and NOx levels and in the erythrocyte GSSG/GSH ratio, whereas melatonin treatment restored the normal values of these parameters. Also, melatonin slightly increased erythrocyte GRd activity without changing GPx activity.

CONCLUSION

For the first time to our knowledge, the results show that during the immediate postoperative period following tooth extraction, there is a significant increase of oxidative stress, which is counteracted by the administration of melatonin into the alveolar sockets.

Structural Determinants for Phosphatidic Acid Regulation of Phospholipase C-β1

Signaling from G protein-coupled receptors to phospholipase C-beta (PLC-beta) is regulated by coordinate interactions among multiple intracellular signaling molecules. Phosphatidic acid (PA), a signaling phospholipid, binds to and stimulates PLC-beta(1) through a mechanism that requires the PLC-beta(1) C-terminal domain. PA also modulates Galpha(q) stimulation of PLC-beta(1). These data suggest that PA may have a key role in the regulation of PLC-beta(1) signaling in cells. The present studies addressed the structural requirements and the mechanism for PA regulation of PLC-beta(1). We used a combination of enzymatic assays, PA-binding assays, and circular dichroism spectroscopy to evaluate the interaction of PA with wild-type and mutant PLC-beta(1) proteins and with fragments of the Galpha(q) binding domain. The results identify a region that includes the alphaA helix and flexible loop of the Galpha(q)-binding domain as necessary for PA regulation. A mutant PLC-beta(1) with multiple alanine/glycine replacements for residues (944)LIKEHTTKYNEIQN(957) was markedly impaired in PA regulation. The high affinity and low affinity component of PA stimulation was reduced 70% and PA binding was reduced 45% in this mutant. Relative PLC stimulation by PA increased with PLC-beta(1) concentration in a manner suggesting cooperative binding to PA. Similar concentration dependence was observed in the PLC-beta(1) mutant. These data are consistent with a model for PA regulation of PLC-beta(1) that involves cooperative interactions, probably PLC homodimerization, that require the flexible loop region, as is consistent with the dimeric structure of the Galpha(q)-binding domain. PA regulation of PLC-beta(1) requires unique residues that are not required for Galpha(q) stimulation or GTPase-activating protein activity.

Parameters of oxidative stress in saliva from diabetic and parenteral drug addict patients

BACKGROUND

Oxidative stress constitutes the basis for many diseases and it may account for the severity of systemic and oral disease complications. The aim of this study was to assess whether saliva may be used to detect the body's oxidative stress level.

METHODS

Oxidative stress was determined in saliva from 14 diabetic patients and 10 heroin addicts; two different pathologic conditions related to free radical damage, and 21 healthy control subjects were included in the study. Glutathione peroxidase (GPx) and reductase (GRd) activities, and glutathione (GSH) and glutathione disulfide (GSSG) levels were analyzed in the saliva of all individuals. Other variables including salivary volume and the oral status were also analyzed.

RESULTS

Diabetic patients had GPx and GRd activities of 39.98 +/- 1.61 and 6.19 +/- 0.61 nmol/min/mg prot, respectively. These values were significantly higher (P < 0.001) than those obtained in control saliva (27.51 +/- 0.86 and 3.44 +/- 0.25 nmol/min/mg prot, respectively). Drug addicts showed significantly (P < 0.001) lower salivary GPx and GRd activities than controls. Both group of patients had significantly lower levels of GSH and higher of GSSG than controls (P < 0.001).

CONCLUSIONS

Changes in the antioxidant enzymes and glutathione levels in saliva from two different pathologic situations as those here studied suggest that this biologic fluid may be suitable for determining the prognosis and evolution of these diseases and its oral manifestations.

Relationship Between Salivary Melatonin and Severity of Periodontal Disease

BACKGROUND

Melatonin possesses antioxidant, free-radical scavenging, and immunoenhancing properties that promote fibroblast activity and bone regeneration. The aim of this study was to examine the possible links between salivary melatonin levels and the severity of periodontal disease using the community periodontal index (CPI).

METHODS

Thirty-seven patients with different degrees of periodontal disease were studied. Salivary and plasma melatonin levels (by radioimmunoassay), salivary/plasma melatonin ratio, and CPI status were collected for each patient. The Spearman correlation coefficient was used to analyze relationships among variables.

RESULTS

Data showed a significant correlation between CPI and salivary/plasma melatonin ratios. When saliva volume was controlled for, a significant correlation (P<0.05) was found between lower salivary melatonin and a worse CPI. This finding suggests that melatonin may act as a protector against free radicals produced by inflammatory periodontal diseases.

CONCLUSIONS

Salivary melatonin levels varied according to the degree of periodontal disease. As the degree of periodontal disease increased, the salivary melatonin level decreased, indicating that melatonin may act to protect the body from external bacterial insults. Therefore, melatonin may be potentially valuable in the treatment of periodontal diseases, although further research is required to validate this hypothesis.

VSV disrupts the Rae1/mrnp41 mRNA nuclear export pathway

Interference with nucleocytoplasmic transport is a strategy employed by certain viruses to compromise host cellular function. While it has been shown that the matrix (M) protein of the vesicular stomatitis virus (VSV) inhibits nuclear export of host cell mRNAs, the underlying mechanism has not been fully established. Here we show that VSV M protein binds the mRNA export factor Rae1/mrnp41. A mutant of M protein defective in Rae1 binding is unable to inhibit mRNA nuclear export. We further show that increased expression of Rae1 fully reverts the inhibition of mRNA export induced by M protein or following virus infection. We found that Rae1 is induced by interferon-gamma, a cytokine that plays a critical role in the immune response to viruses, such as VSV. Thus, these results demonstrate that VSV M protein blocks mRNA export by disrupting Rae1 function, which can be reverted by induction of Rae1 expression.

Bioprosthetic heart valve leaflet deformation monitored by double-pulse stereo photogrammetry

A double-pulse stereo photogrammetry technique has been developed for the dynamic assessment of the leaflet deformation of bioprosthetic heart valves under simulated physiological conditions. By using a specially designed triggering technique, which takes the advantage of the field transfer mechanisms of the charge coupled device camera, two consecutive images separated by a time interval as short as 5 ms were captured. This made it possible to investigate the realistic leaflet deformation during the valve opening and closing processes which typically last 25-45 ms. This technique was applied to assess a newly developed pericardial valve leaflet in a physiological pulse flow loop. Quantitative leaflet deformations of the valve opening and closing were generated from sequences of digital images. The results can later be applied to finite element analysis of bioprosthetic heart valve leaflet stress and strain during a complete cardiac cycle.

Familial hypertrophic cardiomyopathy mutations in the regulatory light chains of myosin affect their structure, Ca2+ binding, and phosphorylation

The effect of the familial hypertrophic cardiomyopathy mutations, A13T, F18L, E22K, R58Q, and P95A, found in the regulatory light chains of human cardiac myosin has been investigated. The results demonstrate that E22K and R58Q, located in the immediate extension of the helices flanking the regulatory light chain Ca(2+) binding site, had dramatically altered Ca(2+) binding properties. The K(Ca) value for E22K was decreased by approximately 17-fold compared with the wild-type light chain, and the R58Q mutant did not bind Ca(2+). Interestingly, Ca(2+) binding to the R58Q mutant was restored upon phosphorylation, whereas the E22K mutant could not be phosphorylated. In addition, the alpha-helical content of phosphorylated R58Q greatly increased with Ca(2+) binding. The A13T mutation, located near the phosphorylation site (Ser-15) of the human cardiac regulatory light chain, had 3-fold lower K(Ca) than wild-type light chain, whereas phosphorylation of this mutant increased the Ca(2+) affinity 6-fold. Whereas phosphorylation of wild-type light chain decreased its Ca(2+) affinity, the opposite was true for A13T. The alpha-helical content of the A13T mutant returned to the level of wild-type light chain upon phosphorylation. The phosphorylation and Ca(2+) binding properties of the regulatory light chain of human cardiac myosin are important for physiological function, and alteration any of these could contribute to the development of hypertrophic cardiomyopathy.

[Bacteremia and recurrent arthritis caused by Streptococcus pyogenes in a heroin addict with AIDS]

BACKGROUND

Streptococcus pyogenes is a bacteria which, at present, is seldom isolated in blood and articular fluid. An intravenous drug addict with human immunodeficiency virus infection, with bacteremia and arthritis by S. pyogenes, associated with tuberculosis is presented.

METHODS

Blood and articular fluid cultures were collected in the usual and Löwenstein-Jensen media.

RESULTS

The patient improved with penicillin and tuberculostatic drugs. Nine months after this episode, the patient reinitiated intravenous drug addiction, and developed another presentation of bacteremia and arthritis by S. pyogenes.

CONCLUSIONS

Heroin addict patients constitute a risk group for bacteremias ans severe infections by S. pyogenes.