Pulp Region Research Articles

Endogenous iron biomineralization in the mouse spleen of metabolic diseases

As the most abundant essential trace element in our human bodies, iron plays essential roles in multiple physiological and pathological conditions, including oxygen transport, cancer, diabetes, Alzheimer's and Parkinson's diseases. Although it has been shown that iron can form particles in some bacteria, migrating birds and fish, whether iron biomineralization can also occur in mammals is still debated. Here we demonstrate that iron metabolism abnormalities in diseased mice can directly lead to endogenous iron biomineralization and particle formation in the spleen. Excessive iron accumulation leads to endogenous particle formation with an averaged size of ∼800 nm. In the spleens of severely diabetic mice, they accumulate in the red pulp region, where the red blood cells are recycled. This directly changes the magnetic property of the spleens and results in spleen damage in a gradient high magnetic field. Therefore, our findings not only demonstrate the existence of endogenous iron biomineralization in metabolic diseases, but also set up a direct link among iron accumulation, magnetic property and magnetic responses of animal organs, which may also be applied in other iron metabolism-related diseases including cancer and Alzheimer's disease.

Monte Carlo Simulation of Diffuse Optical Spectroscopy for 3D Modeling of Dental Tissues.

Three-dimensional precise models of teeth are critical for a variety of dental procedures, including orthodontics, prosthodontics, and implantology. While X-ray-based imaging devices are commonly used to obtain anatomical information about teeth, optical devices offer a promising alternative for acquiring 3D data of teeth without exposing patients to harmful radiation. Previous research has not examined the optical interactions with all dental tissue compartments nor provided a thorough analysis of detected signals at various boundary conditions for both transmittance and reflectance modes. To address this gap, a GPU-based Monte Carlo (MC) method has been utilized to assess the feasibility of diffuse optical spectroscopy (DOS) systems operating at 633 nm and 1310 nm wavelengths for simulating light-tissue interactions in a 3D tooth model. The results show that the system's sensitivity to detect pulp signals at both 633 nm and 1310 nm wavelengths is higher in the transmittance compared with that in the reflectance mode. Analyzing the recorded absorbance, reflectance, and transmittance data verified that surface reflection at boundaries can improve the detected signal, especially from the pulp region in both reflectance and transmittance DOS systems. These findings could ultimately lead to more accurate and effective dental diagnosis and treatment.

Microbiota-mediated shaping of mouse spleen structure and immune function characterized by scRNA-seq and Stereo-seq

Gut microbes exhibit complex interactions with their hosts and shape an organism's immune system throughout its lifespan. As the largest secondary lymphoid organ, the spleen has a wide range of immunological functions. To explore the role of microbiota in regulating and shaping the spleen, we employ scRNA-seq and Stereo-seq technologies based on germ-free (GF) mice to detect differences in tissue size, anatomical structure, cell types, functions, and spatial molecular characteristics. We identify 18 cell types, 9 subtypes of T cells, and 7 subtypes of B cells. Gene differential expression analysis reveals that the absence of microorganisms results in alterations in erythropoiesis within the red pulp region and congenital immune deficiency in the white pulp region. Stereo-seq results demonstrate a clear hierarchy of immune cells in the spleen, including marginal zone (MZ) macrophages, MZ B cells, follicular B cells and T cells, distributed in a well-defined pattern from outside to inside. However, this hierarchical structure is disturbed in GF mice. Ccr7 and Cxcl13 chemokines are specifically expressed in the spatial locations of T cells and B cells, respectively. We speculate that the microbiota may mediate the structural composition or partitioning of spleen immune cells by modulating the expression levels of chemokines.

P3 Flap: Technique for Fingertip Reconstruction

Summary: Fingertip amputations represent an important spectrum of injuries, and most are avulsions or crush trauma. There is no consensus about one single standard treatment, and a wide number of techniques are available. The authors present the P3 flap as an option for covering fingertip defects with bone exposure, avoiding painful scars in the pulp area, without a donor site. This study included 12 fingertips with amputated segment not available for replantation. Volar oblique fingertip defects and transverse amputations with bone exposure, not more proximal than Hirase Zone IIB, were included. Defects were less than 2 cm. The patients were followed up for an average of 6 months. The aesthetic and functional outcomes and fingertip discrimination recovery were evaluated at 6 months by the static two-point discrimination (2-PD) test and DASH score (quick version). The average postoperative 2-PD test at 6 months was 5.9 mm (range from 5 to 8 mm). The mean healing time of the fingertip was 4 weeks. Nail deformity was reported in three cases with level IIB of amputation. None of the P3 flaps failed, and local infection was not reported. The average DASH score at 6 months was 1.1. The mean time to return to work was 38 days (range from 30 to 53). The P3 flap proposed in this study demonstrates a reliable single-stage technique, performed under local anesthesia, for fingertip defect reconstruction, avoiding skin incision and scars in the pulp region and preserving digital length and nail bed.

Characterization of Neuro-Immune Communication in the White Pulp Region of the Spleen

Abstract Norepinephrine (NE) is a ubiquitous neurotransmitter that facilitates cellular communication in the sympathetic nervous system. Recent advancements have shown sympathetic neurons innervate secondary immune organs, such as the spleen, to control immune physiology. Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique that varies an applied potential at a very fast scan rate with micro-electrodes to detect neurotransmitters with high temporal and spatial resolution. FSCV can be used to detect the sub-second release of NE in an ex vivomurine slice model to study the mechanisms related to neuro-immune communication. Our lab is the first to characterize and quantify this spontaneous transient signaling of catecholamines in the white pulp region of the murine spleen with FSCV. The average concentration of catecholamines released is 581 ± 20 nM, with an average inter-event time of 23.4 ± 0.7 s and a duration of 6.6 ± 0.1 s. Norepinephrine transporter (NET) is known to transport NE back into cells after endogenous release. We blocked NET with the inhibitor nomifensine to provide further evidence of NE release and study the mechanisms involved in NE uptake. To study the mechanisms of NE release in the spleen, we blocked α2-adrenoceptor, a known autoreceptor only found on neurons. Yohimbine is an α2-adrenoceptor antagonist, and when applied to slices, it increased catecholamine concentration and duration, demonstrating that we are detecting neuronal release of NE. Furthermore, we used ELISAs to quantify the extent to which the α2-adrenoceptor affects cytokine production, providing further evidence neuronal-regulated immune signaling in the white pulp region of the spleen. Supported by grants from NIH (R01AI151552, R01NS121426)

Skeletal stem/progenitor cells provide the niche for extramedullary hematopoiesis in spleen.

In bone marrow, the niche which supports hematopoiesis and nurtures hematopoietic stem cells (HSCs) contains perivascular reticular cells representing a subset of skeletal stem/progenitor cells (SSPCs). These stromal cells which provide the niche are lost or become inadequate during stress, disease or ageing, such that HSCs leave bone marrow and enter spleen and other peripheral sites to initiate extramedullary hematopoiesis and particularly myelopoiesis. Spleen also maintains niches for HSCs under steady-state conditions, evident since neonatal and adult spleen contain HSCs in low number and provide low-level hematopoiesis. In spleen, HSCs are found in the sinusoidal-rich red pulp region also in the vicinity of perivascular reticular cells. These cells resemble to some extent the known stromal elements reflecting HSC niches in bone marrow, and are investigated here for their characteristics as a subset of SSPCs. The isolation of spleen stromal subsets and the generation of cell lines which support HSCs and myelopoiesis in vitro has led to the identification of perivascular reticular cells which are unique to spleen. Analysis of gene and marker expression, as well as differentiative potential, identifies an osteoprogenitor cell type, reflective of one of several subsets of SSPCs described previously in bone, bone marrow and adipose tissue. The combined information supports a model for HSC niches in spleen involving perivascular reticular cells as SSPCs having osteogenic, stroma-forming capacity. These associate with sinusoids in red pulp to form niches for HSCs and to support the differentiation of hematopoietic progenitors during extramedullary hematopoiesis.

Effect of non-steroidal anti-inflammatory drugs on pulpal and periapical inflammation induced by lipopolysaccharide.

The objective of this study was to evaluate the effect of non-steroidal anti-inflammatory drugs (NSAIDs) in controlling pulpal and periapical inflammation in vivo as a potential coadjutant systemic therapy for pulpitis. A suspension containing E. coli lipopolysaccharide (LPS; 1.0 μg/μL) was inoculated into the pulp chamber of the first molars of C57BL/6 mice (n = 72), and the animals were treated daily with indomethacin or celecoxib throughout the experimental periods. After 7, 14, 21, and 28 days, the tissues were removed for histopathological, histoenzymology, histometric, and immunohistochemical evaluation. Inoculation of LPS into the pulp chamber induced the synthesis of the enzyme cyclooxygenase-2 (COX-2) in dental pulp and periapical region. Indomethacin and celecoxib treatment changed the profile of inflammatory cells recruited to dental pulp and to the periapex, which was characterized by a higher mononuclear cell infiltrate, compared to LPS inoculation alone which recruited a higher amount of polymorphonuclear neutrophils. Administration of indomethacin for 28 days resulted in the development of apical periodontitis and increased osteoclast recruitment, unlike celecoxib. NSAIDs indomethacin and celecoxib changed the recruitment of inflammatory cells to a mononuclear profile upon inoculation of LPS into the pup chamber, but indomethacin enhanced periapical bone loss whereas celecoxib did not. Celecoxib, a selective COX-2 inhibitor, can change the profile of inflammatory cells recruited to the dental pulp challenged with LPS and might a be potential systemic coadjutant for treatment of pulpitis.

Measurement of biomechanical behavior of dentin hard tissue in response to unbound water loss using stereo-digital image correlation

Understanding the biomechanical behavior of dentin hard tissue with fluid-filled dentin tubules and hydrated matrices is essential for studying this functionally graded biological composite. The stereo-digital image correlation technique with an adaptive high-magnification field of view (FOV) for fully hydrated biological tissue measurement was investigated. The adaptive magnification is controlled by the length of extension tubes. To determine both the unbound water loss induced and load-induced three-dimensional (3D) deformation of dentin hard tissue from a fully hydrated state to a non-hydrated condition, samples of dentin blocks and half teeth in sagittal sections were studied for a period of 2 h in situ over varied speckle patterns. The effects of speckles on water evaporation, camera pre-heating, and measurement accuracy in the wet, curved and long-term measurement were analyzed. The elastic modulus and Poisson’s ratio of both dentin and pulp in response to unbound water evaporation were measured. With the unbound water loss, the mean values of the elastic modulus generally increased from ∼8 GPa to ∼10 GPa in pulp region and from ∼10 GPa to ∼12 GPa in dentin region. The mean values of the Poisson’s ratio increased both in pulp and in dentin. Poisson’s ratio in the dentin regions (∼0.3) were generally smaller than those in the pulp regions (even can reach 0.6), irrespective of the partial dehydration time. Further analysis of the full-field deformation results provided insight into the unbound water-induced regional deformations and mechanical changes in human dentin. It’s found that the unbound water loss induced deformations were more prominent when compared to load induced deformations.

Stable expression ratios of five pyroptosis-inducing cytokines in the spleen and thymus of mice showed potential immune regulation at the organ level.

The immune system is one of the most complex regulatory systems in the body and is essential for the maintenance of homeostasis. Despite recent breakthroughs in immunology, the regulation of the immune system and the etiology of autoimmune diseases such as lupus remain unclear. Systemic lupus erythematosus is a systemic autoimmune disease with abnormally and inconsistently expressed pro-inflammatory cytokines. Pyroptosis is a pro-inflammatory form of programmed cell death that is associated with systemic lupus erythematosus. The thymus and spleen are important immune organs involved in systemic lupus erythematosus. Therefore, this study investigated the difference in expression of pyroptosis-inducing pro-inflammatory cytokines between the spleen and thymus in lupus model mice and in control mice, to describe immune regulation at the organ level. To investigate differences in the expression of pyroptosis-inducing cytokines in the spleen and thymus and to explore immune regulatory networks at the organ level. Two groups of lupus mice and two groups of control mice were utilized for this study. Using the thymus and spleen of experimental animals, mRNA expression levels of five pyroptosis-inducing cytokines (interleukin 1β, interleukin 18, NLRP3, caspase-1 and TNF-α) were determined via quantitative polymerase chain reaction. In addition, tissue distribution of these cytokines was investigated via immunohistochemistry. All five pyroptosis-inducing inflammatory cytokines showed higher expression in the spleen than in the thymus (p < 0.05). Moreover, the spleen/thymus expression ratios of all five pyroptosis-inducing cytokines were not statistically different between the four experimental groups. Expression of all five cytokines exhibited a stable ratio (spleen/thymus ratios). This distinctive stable spleen/thymus ratio was consistent in all four experimental groups. The stable spleen/thymus ratios of the five inflammatory cytokines were as follows: interleukin 1β (2.02 ± 0.9), interleukin 18 (2.07 ± 1.06), caspase-1 (1.93 ± 0.66), NLRP3 (3.14 ± 1.61) and TNF-α (3.16 ± 1.36). Immunohistochemical analysis showed the cytokines were mainly expressed in the red pulp region of the spleen and the medullary region of the thymus, where immune-activated cells aggregated. The stable spleen/thymus expression ratios of pyroptosis-inducing cytokines indicated that immune organs exhibit strictly regulated functions to maintain immune homeostasis and adapt to the environment.

288 Se deficiency aggravates AFB1-induced immunotoxicity in chick spleen via regulating six selenoprotein and redox/inflammation/apoptotic signaling

Abstract This study was designed to reveal the underlying mechanism of Se-mediated protection against aflatoxin B1 (AFB1)-induced splenic injury in broilers. Four groups of day-old Cobb male broilers (n = 5 cages/diet, 6 chicks/cage) were arranged in a 3-wk 2×2 factorial design trial that fed a Se-deficient, corn and soy–based diet (BD, 36 μg Se/kg) or the BD + 1.0 mg AFB1/kg, 0.3 mg Se/kg, or 1.0 mg AFB1/kg with 0.3 mg Se/kg (as 2-hydroxy-4-methylselenobutanoic acid). Serum and spleen were collected at wk 3 to assay for histology, cytokines, redox status, and selected inflammation- and apoptosis-related genes and proteins, and selenogenome. Dietary AFB1 induced the growth retardation and spleen injury, decreasing (P &amp;lt; 0.05) body weight gain, feed intake, feed conversion efficiency, and serum interleukin-1β, increasing (P &amp;lt; 0.05) spleen index and serum interleukin-6, and reduced the splenic lymphocyte number and white pulp region and histiocyte proliferation in Se adequate groups. However, Se deficiency aggravated (P &amp;lt; 0.05) these AFB1-induced changes. Moreover, Se deficiency decreased (P &amp;lt; 0.05) splenic glutathione peroxidases (GPX) activities and glutathione concentration in AFB1 exposed groups. Furthermore, Se deficiency also upregulated (P &amp;lt; 0.05) the antimicrobial (beta defensin 1 and 2) and apoptotic (Caspase 3 and Caspase 9) genes but downregulated (P &amp;lt; 0.05) antiapoptotic (B-cell lymphoma 2) and inflammatory (E3 ubiquitin-protein ligase CBL-B) genes at mRNA and(or) protein levels in AFB1 supplementation groups. Additionally, Se deficiency downregulated (P &amp;lt; 0.05) GPX3, thioredoxin reductase 1 (TXNRD 1), GPX4 and selenoprotein (SELENO) S and upregulated (P &amp;lt; 0.05) SELENOT and SELENOU in spleen in AFB1 administered groups. In conclusions, dietary Se deficiency aggravated AFB1-induced spleen injury in chicks, partially through the regulation of the oxidative stress, inflammatory and apoptotic signaling and six selenoproteins (Supported in part by Chinese Natural Science Foundation Projects 31772636 and 31501987).

Regeneration of Neural Networks in Immature Teeth with Non-Vital Pulp Following a Novel Regenerative Procedure.

Background and ObjectivesRecombinant amelogenin protein (RAP) was reported to induce soft-tissue regeneration in canine infected endodontically treated permanent teeth with open apices. To characterize identities of the cells found in the RAP regenerated tissues compared to authentic pulp by identifying: 1) stem cells by their expression of Sox2; 2) nerve fibers by distribution of the axonal marker peripherin; 3) axons by their expression of calcitonin gene–related peptide (CGRP); 4) the presence of astrocytes expressing glial fibrillary acidic proteins (GFAP).MethodsA total of 240 open-apex root canals in dogs were used. After establishment of oral contamination to the pulp, the canals were cleaned, irrigated, and 120 canals filled with RAP, and the other 120 with calcium hydroxide.ResultsAfter 1, 3, and 6 months, teeth were recovered for immune-detection of protein markers associated with native pulp tissues. Regenerated pulp and apical papilla of RAP group revealed an abundance of stem cells showing intense immunoreactivity to Sox2 antibody, immunoreactivity of peripherin mainly in the A-fibers of the odontoblast layer and immunoreactivity to CGRP fibers in the central pulp region indicative of C-fibres. GFAP immunoreactivity was observed near the odontoblastic, cell-rich regions and throughout the regenerated pulp.ConclusionsRAP induces pulp regeneration following regenerative endodontic procedures with cells identity by gene expression demonstrating a distribution pattern similar to the authentic pulp innervation. A- and C-fibers, as well as GFAP specific to astrocytic differentiation, are recognized. The origin of the regenerated neural networks may be derived from the Sox2 identified stem cells within the apical papilla.

Selenium Deficiency Aggravates Aflatoxin B1–Induced Immunotoxicity in Chick Spleen by Regulating 6 Selenoprotein Genes and Redox/Inflammation/Apoptotic Signaling

Selenium (Se) plays a protective role in aflatoxin B1 (AFB1)-induced splenic immunotoxicity in chicks. This study was designed to reveal the underlying mechanism of Se-mediated protection against AFB1-induced splenic injury in broilers. Four groups of 1-d-old Cobb male broilers (n=5 cages/diet, 6 chicks/cage) were arranged in a 3-wk 2×2 factorial design trial whereby they were fed an Se-deficient, corn- and soy-based diet [base diet (BD), 36 μg Se/kg], BD plus 1.0 mg AFB1/kg, BD plus 0.3 mg Se/kg, or BD plus 1.0 mg AFB1/kg and 0.3 mg Se/kg (as 2-hydroxy-4-methylselenobutanoic acid). Serum and spleen were collected at week 3 to assay for cytokines, histology, redox status, selected inflammation- and apoptosis-related genes and proteins, and the selenogenome. Dietary AFB1 induced growth retardation and spleen injury, decreasing (P<0.05) body weight gain, feed intake, feed conversion efficiency, and serum interleukin-1β by 17.8-98.1% and increasing (P<0.05) the spleen index and serum interleukin-6 by 37.6-113%. It also reduced the splenic lymphocyte number, the white pulp region, and histiocyte proliferation in Se-adequate groups. However, Se deficiency aggravated (P<0.05) these AFB1-induced alterations by 16.2-103%. Moreover, Se deficiency decreased (P<0.05) splenic glutathione peroxidase (GPX) activity and glutathione-S transferase and glutathione concentrations by 35.6-89.4% in AFB1-exposed groups. Furthermore, Se deficiency upregulated (P<0.05) the apoptotic (Caspase 3 and Caspase 9) and antimicrobial (β defensin 1 and 2) genes, but downregulated (P<0.05) antiapoptotic (B-cell lymphoma 2) and inflammatory (E3 ubiquitin-protein ligase CBL-B) genes at the mRNA and/or protein level in AFB1 supplementation groups. Additionally, Se deficiency downregulated (P<0.05) GPX3, thioredoxin reductase 1 (TXNRD 1), GPX4, and selenoprotein (SELENO) S, and upregulated (P<0.05) SELENOT and SELENOU in spleen in AFB1 administered groups. Dietary Se deficiency exacerbated AFB1-induced spleen injury in chicks, partially through the regulation of oxidative stress, inflammatory and apoptotic signaling, and 6 selenoproteins.

Impact of autophagic regulation on splenic red pulp macrophages during cerebral malarial infection

Splenic red pulp macrophages play a critical role infiltration of infected RBC and elimination of pathogens during malarial infection. However, the efficiency of pathogenic processing and the intricate pathway followed by them to boost the downstream immune response has not been studied in details. We checked the status of autophagic regulation within the cells both before and after the infection and also modulated the autophagic flux with either its inducer or inhibitor. We found that the upregulation of autophagic gene and the corresponding pathway is correlated with better parasite clearance and survivability, with an enhanced downstream immune response. It also increases their phagocytic potential with better Lysosomal associated protein I and II synthesis. The autophagolysosome formation increases as well, and more vacuole bound LC3B protein are detected. Chemokine synthesized from Red Pulp macrophage helps in mediating the induction for recruiting neutrophil and CD4 + T cells to the splenic red pulp region. The skewing of M1 macrophage polarity is observed post autophagic induction with a better costimulatory molecule like CD80, CD86 expression and antigen presenting molecule MHC I, MHC II is observed. This study shows the possibility of an alternative or adjuvant therapy regimen for the malarial patient by inducing the autophagic pathway that targets the red pulp macrophages. This might be helpful for better pathogen degradation and processing. The subsequent clearance of parasite will result in a better outcome for the patients.

Acute Dental Pain and Salivary Biomarkers for Stress and Inflammation in Patients with Pulpal or Periapical Inflammation

To investigate whether acute dental pain due to pulpal or periapical inflammation is associated with increased expression of cortisol and inflammatory markers and mediators in the saliva, as well as changes in salivary flow rate. Patients experiencing pain (n = 42) were recruited when seeking emergency dental treatment. A 0 to 10 numeric rating scale (NRS) was used as a measure of the severity of pain, and the number of days with pain sensation was also recorded. Unstimulated saliva was collected for 3 minutes (salivary flow measured in mL/minute) and stored at -80°C. Saliva was analyzed for the biomarkers cortisol, C-reactive protein (CRP), and cytokines interleukin-1β (IL-1β) and interleukin-6. In addition, the participants completed a simple questionnaire about stress-inducing factors such as insomnia, dental anxiety, or home/workplace stress. Patients received a dental examination and diagnosis (eg, symptomatic pulpitis/apical periodontitis or acute apical abscess), which was confirmed during dental treatment. The control group (n = 39) consisted of participants without any pain and no known medical or dental problems. Patients experiencing acute pain due to pulpal or periapical inflammation had a mean NRS score of 7.0 ± 2.59. The mean duration of pain was 6.5 ± 7.9 days. There was no significant difference in pain level between male and female subjects, tooth type affected, or diagnosis. Higher levels of cortisol, IL-1β, and IL-6 and increased salivary flow were detected in patients with pain when compared to controls (P < .05). CRP was higher in patients with acute pain compared to control participants without pain, but this difference was not statistically significant. Stress at home or the workplace was reported by 79% of patients experiencing pain and by 28% of control participants. Acute dental pain due to pulpal or periapical inflammation was associated with an increase in salivary cortisol, IL-1β, and IL-6 levels and in salivary flow rate. Stress arising from home or the workplace may aggravate a symptom-free pulpal or periapical inflammation to an acute phase. Inflammation in the pulp and periapical region can have effects in regions remote from the disease site.

Biodistribution of PNIPAM-Coated Nanostructures Synthesized by the TDMT Method.

Targeting the spleen with nanoparticles could increase the efficacy of vaccines and cancer immunotherapy, and have the potential to treat intracellular infections including leishmaniasis, trypanosome, splenic TB, AIDS, malaria, and hematological disorders. Although, nanoparticle capture in both the liver and spleen has been well documented, there are only a few examples of specific capture in the spleen alone. It is proposed that the larger the nanoparticle size (>400 nm) the greater the specificity and capture within the spleen. Here, we synthesized five nanostructures with different shapes (ranging from spheres, worms, rods, nanorattles, and toroids) and poly( N-isopropylacrylamide), PNIPAM, surface coating using the temperature-directed morphology transformation (TDMT) method. Globular PNIPAM (i.e., water insoluble) surface coatings have been shown to significantly increase cell uptake and enhanced enzyme activity. We incorporated a globular component of PNIPAM on the nanostructure surface and examined the in vivo biodistribution of these nanostructures and accumulation in various tissues and organs in a mouse model. The in vivo biodistribution as a function of time was influenced by the shape and PNIPAM surface composition, in which organ capture and retention was the highest in the spleen. The rods (∼150 nm in length and 15 nm in width) showed the highest capture and retention of greater than 35% to the initial injection amount compared to all other nanostructures. It was found that the rods specifically targeted the cells in the red pulp region of the spleen due to the shape and PNIPAM coating of the rod. This remarkable accumulation and selectively into the spleen represents new nanoparticle design parameters to develop new splenotropic effects for vaccines and other therapeutics.

Characterization of microRNAs expression profiles in human dental-derived pluripotent stem cells.

Induced pluripotent stem cells (iPSCs) technology provides a powerful means to generate and regenerate unlimited pluripotent stem cells directly from body tissue cells. Stem cells from apical papilla (SCAP) and Dental pulp stem cells (DPSCs) are present in ‘cell-rich zones’ within the dental pulp region, which are capable of regenerating pulp and dentin tissues in vivo. In this study, we investigated the difference of miRNAs expression in SCAPs and DPSCs before and after the reprogramming. Using miRNA microarray, 134 and 265 differentially expressed miRNAs in DPSCs- and SCAP-iPSCs were up-regulated compared to these before reprogramming. 117 specific miRNAs with enhanced more than 2-fold were identified in both DPSCs- and SCAP-iPSCs. Among the co-regulated miRNAs, miR-19a-3p, miR-92b-3p and miR-130b-3p showed the maximum difference, which had involvement in the cell cycle, TGF beta signaling pathway and epithelial mesenchymal transition. Using qRT-PCR analysis, the expression of miR-19a-3p, miR-92b-3p and miR-130b-3p indicated substantial increases in DPSCs-iPSCs and SCAP-iPSCs. The findings suggest that miRNAs play a part in the difference between DPSCs-iPSCs and DPSCs, as well as between SCAP-iPSCs and SCAP. The variation of miRNA expression in reprogrammed dental-derived pluripotent stem cells revealed different characteristics induced by iPSC generation.

Dental biofilm infections - an update.

Teeth are colonized by oral bacteria from saliva containing more than 700 different bacterial species. If removed regularly, the dental biofilm mainly comprises oral streptococci and is regarded as resident microflora. But if left undisturbed, a complex biofilm containing up to 100 bacterial species at a site will build up and may eventually cause development of disease. Depending on local ecological factors, the composition of the dental biofilm may vary considerably. With access to excess carbohydrates, the dental biofilm will be dominated by mainly gram-positive carbohydrate-fermenting bacteria causing demineralization of teeth, dental caries, which may further lead to inflammation and necrosis in the pulp and periapical region, i.e., pulpitis and periapical periodontitis. In supra- and subgingival biofilms, predominantly gram-negative, anaerobic proteolytic bacteria will colonize and cause gingival inflammation and breakdown of supporting periodontal fibers and bone and ultimately tooth loss, i.e., gingivitis, chronic or aggressive periodontitis, and around dental implants, peri-implantitis. Furthermore, bacteria from the dental biofilm may spread to other parts of the body by bacteremia and cause systemic disease. Basically, prevention and treatment of dental biofilm infections are achieved by regular personal and professional removal of the dental biofilm.

Antimicrobial Efficacy of Mineral Trioxide Aggregate against Therapy Resistant Endodontic Microorganisms

Microorganisms, usually from the dental caries, are the main sources of diseases in dental pulp (root canals) and periapical region. Facultative bacteria and fungi have been identified in therapy resistant persistent endodontic infection. The objectives of this study was to evaluate the antimicrobial efficacy of Mineral Tri Oxide Aggregate (MTA) against therapy resistant endodontic microorganisms. The efficacy of MTA was also compared with that of calcium hydroxide. Six standard bacterial stains were used: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, bacillus subtilis, Candida albicans and Enterococcus faecalis. The agar diffusion method on Muller- Hilton media was employed. The plates containing media were inoculated with the specified bacterial suspensions. Two standard holes were prepared on each microorganism inoculated plate with a copper puncher and one hole was completely filled with MTA &amp; the other with Ca (OH)2 . The plates were then kept at environmental temperature for one hour to ensure prediffusion and then incubated at 370C for 24 hours. After 24 hours, the diameters of inhibition zones were measured. Tests were replicated for thirty times for each sample and mean values were taken. Zone of inhibition as measured for MTA and Ca (OH)2 were statistically analyzed with Student’s t-Test and Post Hoc Games Howell Test and were presented as mean ± SD to compare of efficacy of MTA and calcium hydroxide on different microorganisms. Both MTA and Ca(OH)2 were found to produce zone of inhibition against Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), , Bacillus subtilis (BTCC 17 ), and Candida albicans (BTCC 493). MTA showed highest activity against S. aureus and lowest activity against P. aeruginosa which was similar to the activity range of Ca (OH)2 against the mentioned organisms. But both of them failed to produce any activity against E. coli and. E. faecalis. MTA was found to produce a lower efficacy than Ca (OH)2 while comparing the zone of inhibition between them and statistically it was significant. Mineral Tri Oxide Aggregate (MTA) showed antimicrobial efficacy against some therapy resistant microorganisms but it did not show antimicrobial efficacy against Escherichia coli and Enterococcus faecalis. MTA was found to produce a lower antimicrobial efficacy than Ca (OH)2.J Bangladesh Coll Phys Surg 2015; 33(3): 140-145

Cucumarioside A2-2 causes changes in the morphology and proliferative activity in mouse spleen

The immunomodulatory effect of triterpene glycoside cucumarioside A2-2 (CA2-2), isolated from the Far Eastern sea cucumber Cucumaria japonica, on the mouse spleen was investigated in comparison with lipopolysaccharide (LPS). It has been shown that the intraperitoneal (i.p.) glycoside administration did not influence on splenic weights, while the statistically significant increase in splenic weight was observed after LPS administration. Changes in the ratio of red to white pulp after CA2-2 or LPS administration were observed. The proportion of splenic white pulp after glycoside or LPS administration increased by up to 34% and 36%, respectively. A detailed study of the distribution of the РСNA (Proliferating Cell Nuclear Antigen) marker showed that the proliferative activity in the white pulp under CA2-2 and LPS influence increased 2.07 and 2.24 times, respectively. The localization of PCNA-positive nuclei in the white pulp region, as well as their dimensional characteristics, suggests that a large proportion of the proliferating cell population consisted of B cells. The mass spectrometry profiles of spleen peptide/protein homogenate were obtained using the MALDI-TOF-MS (Matrix −Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry) approach. It was found that i.p. stimulation of animals with CA2-2 or LPS leads to marked changes in the intensity of revealed characteristic peaks of peptides/proteins after exposure to immunostimulants.

Protective Effect of Spirodela polyrhiza on Various Organs of Arsenicinduced Wistar Albino Rats

Our study was undertaken to assess the protective effect of Spirodela polyrhiza against sodium arseniteinduced toxicity in experimental model. Animals were divided into six groups. The first group was used as control group while the other groups were treated with S. polyrhiza, sodium arsenite (10 ppm), 10 ppm As plus S. polyrhiza, sodium arsenite (30 ppm), and 30 ppm As plus S. polyrhiza respectively. Organs (kidney, spleen and heart) were collected at the end of the experiment for conducting histopathological analysis and measuring the amount of deposited arsenic. Tubular epithelium necrosis was seen affecting less than 50% of all renal specimens, on the other hand slightly enlarged white pulp region in splenic tissue were found in the groups of Wistar rat where S. polyrhiza and arsenic was administered concomitantly. Moreover, the observed moderate tissue changes (edema and muscle necrosis) in cardiac specimens of arsenic treated groups were found to be mild in the S. polyrhiza +arsenic treated groups. It is noteworthy to mention that S. polyrhiza not only reversed the arsenic-induced toxicity but also reduced the tissue arsenic load in Wistar rats to a considerable extent. Overall, the results indicated that S. polyrhiza might become useful in mitigating the toxic effects of arsenic.