Gray matter volume alterations in de novo Parkinson's disease: A mediational role in the interplay between sleep quality and anxiety.

OBJECTIVE: Parkinson's disease (PD) is increasingly recognized for its non-motor symptoms, among which emotional disturbances and sleep disorders frequently co-occur. The commonality of neuroanatomical underpinnings for these symptoms is not fully understood. This study is intended to investigate the differences in gray matter volume (GMV) between PD patients with anxiety (A-PD) and those without anxiety (NA-PD). Additionally, it seeks to uncover the interplay between GMV variations and the manifestations of anxiety and sleep quality. METHODS: A total of 37 A-PD patients, 43 NA-PD patients, and 36 healthy controls (HCs) were recruited, all of whom underwent voxel-based morphometry (VBM) analysis. Group differences in GMV were assessed using analysis of covariance (ANCOVA). Partial correlation between GMV, anxiety symptom, and sleep quality were analyzed. Mediation analysis explored the mediating role of the volume of GMV-distinct brain regions on the relationship between sleep quality and anxiety within the PD patient cohort. RESULTS: A-PD patients showed significantly lower GMV in the fusiform gyrus (FG) and right inferior temporal gyrus (ITG) compared to HCs and NA-PD patients. GMV in these regions correlated negatively with Hamilton Anxiety Rating Scale (HAMA) scores (right ITG: r = -0.690, p < 0.001; left FG: r = -0.509, p < 0.001; right FG: r = -0.576, p < 0.001) and positively with sleep quality in PD patients (right ITG: r = 0.592, p < 0.001; left FG: r = 0.356, p = 0.001; right FG: r = 0.470, p < 0.001). Mediation analysis revealed that GMV in the FG and right ITG mediated the relationship between sleep quality and anxiety symptoms, with substantial effect sizes accounted for by the right ITG (25.74%) and FG (left: 11.90%, right: 15.59%). CONCLUSION: This study has shed further light on the relationship between sleep disturbances and anxiety symptoms in PD patients. Given the pivotal roles of the FG and the ITG in facial recognition and the recognition of emotion-related facial expressions, our findings indicate that compromised sleep quality, under the pathological conditions of PD, may exacerbate the reduction in GMV within these regions, impairing the recognition of emotional facial expressions and thereby intensifying anxiety symptoms.

Pyroptotic macrophages induce disruption of glutamate metabolism in periodontal ligament stem cells contributing to their compromised osteogenic potential.

Macrophage pyroptosis is of key importance to host defence against pathogen infections and may participate in the progression and recovery of periodontitis. However, the role of pyroptotic macrophages in regulating periodontal ligament stem cells (PDLSCs), the main cell source for periodontium renewal, remains unclear. First, we found that macrophage pyroptosis were enriched in gingiva tissues from periodontitis patients compared with those of healthy people through immunofluorescence. Then the effects of pyroptotic macrophages on the PDLSC osteogenic differentiation were investigated in a conditioned medium (CM)-based coculture system in vitro. CM derived from pyroptotic macrophages inhibited the osteogenic differentiation-related gene and protein levels, ALP activity and mineralized nodule formation of PDLSCs. The osteogenic inhibition of CM was alleviated when pyroptosis was inhibited by VX765. Further, untargeted metabolomics showed that glutamate limitation may be the underlying mechanism. However, exogenous glutamate supplementation aggravated the CM-inhibited osteogenic differentiation of PDLSCs. Moreover, CM increased extracellular glutamate and decreased intracellular glutamate levels of PDLSCs, and enhanced the gene and protein expression levels of system xc - (a cystine/glutamate antiporter). After adding cystine to CM-based incubation, the compromised osteogenic potency of PDLSCs was rescued. Our data suggest that macrophage pyroptosis is related to the inflammatory lesions of periodontitis. Either pharmacological inhibition of macrophage pyroptosis or nutritional supplements to PDLSCs, can rescue the compromised osteogenic potency caused by pyroptotic macrophages.

Long non-coding RNA AC018926.2 regulates palmitic acid exposure-compromised osteogenic potential of periodontal ligament stem cells via the ITGA2/FAK/AKT pathway.

Although obesity has been proposed as a risk factor for periodontitis, the influence of excessive fat accumulation on the development of periodontitis and periodontal recovery from disease remains largely unknown. This study investigated the cellular response of periodontal ligament stem cells (PDLSCs) to elevated levels of a specific fatty acid, namely, palmitic acid (PA). The mechanism by which PA exposure compromises the osteogenic potential of cells was also explored. It was found that exposure of PDLSCs to abundant PA led to decreased cell osteogenic differentiation. Given that long non-coding RNAs (lncRNAs) play a key role in the stem cell response to adverse environmental stimuli, we screened the lncRNAs that were differentially expressed in PDLSCs following PA exposure using lncRNA microarray analysis, and AC018926.2 was identified as the lncRNA that was most sensitive to PA. Next, gain/loss-of-function studies illustrated that AC018926.2 was an important regulator in PA-mediated osteogenic differentiation of PDLSCs. Mechanistically, AC018926.2 upregulated integrin α2 (ITGA2) expression and therefore activated ITGA2/FAK/AKT signalling. Further functional studies revealed that inactivation of ITGA2/FAK/AKT signalling by silencing ITGA2 counteracted the pro-osteogenic effect induced by AC018926.2 overexpression. Moreover, the results of bioinformatics analysis and RNA immunoprecipitation assay suggested that AC018926.2 might transcriptionally regulate ITGA2 expression by binding to PARP1 protein. Our data suggest that AC018926.2 may serve as a therapeutic target for the management of periodontitis in obese patients.

Clinical efficacy of electromagnetic field therapy combined with traditional Chinese pain-reducing paste in myofascial pain syndrome.

BACKGROUND: Pulsed electromagnetic field (PEMF) therapy is widely used to treat myofascial pain syndrome (MPS). Damp-clearing and pain-reducing paste (DPP) comprises medical herbs and has been a traditional method of reducing myofascial pain in China for a long time, and it is usually administered with heating. However, the synergistic effect of PEMF therapy on heating-DPP in patients with MPS is unclear. AIM: To investigate the synergistic effect of PEMF therapy plus heating-DPP in lumbar MPS. METHODS: This double-blind, randomized, placebo-controlled trial was conducted on 120 patients with lumbar MPS who were randomly divided into an experimental group (EG, n = 60) and a control group (CG, n = 60). Patients in both groups were treated with heating-DPP combined with PEMF therapy; however, the electromagnetic function of the therapeutic apparatus used in the CG was disabled. Each treatment lasted for 20 min and was applied five times a week for two weeks. The short-form McGill Pain Questionnaire was applied at five time points: pretest, end of the first and second weeks of treatment, and end of the first and fourth week after completing treatment. Visual analog scale (VAS), present pain intensity index (PPI), and pain rating index (PRI; total, affective pain, and sensory pain scores) scores were then analyzed. RESULTS: Compared with the CG, the VAS, PPI and PRI scores (total, affective pain and sensory pain scores) in the EG were significantly lower after treatment and during follow-up. CONCLUSION: PEMF therapy combined with heating-DPP showed better efficacy than heating-DPP alone in reducing the overall intensity of pain and sensory and affective pain.

Gold nanoparticles targeting the autophagy-lysosome system to combat the inflammation-compromised osteogenic potential of periodontal ligament stem cells: From mechanism to therapy.

Although substantial data indicate that the osteogenic potential of periodontal ligament stem cells (PDLSCs) is compromised under inflammatory conditions, the underlying mechanism remains largely unexplored. In this study, we found that both the autophagy levels and autophagic flux levels were decreased in PDLSCs incubated under inflammatory conditions (I-PDLSCs). Based on the increased expression of LC3 II (at an autophagy level) and decreased accumulation of LC3 II (at an autophagic flux level) in I-PDLSCs, we speculated that the disruption of I-PDLSC autophagy arose from dysfunction of the cellular autophagy-lysosome system. Subsequently, our hypothesis was demonstrated by inhibited autophagosome-lysosome fusion, damaged lysosomal function, and suppressed activation of transcription factor EB (TFEB, a master regulator of the autophagy-lysosome system) in I-PDLSCs and verified by TFEB overexpression in I-PDLSCs. We found that gold nanoparticle (Au NP) treatment rescued the osteogenic potential of I-PDLSCs by restoring the inflammation-compromised autophagy-lysosome system. In this context, Au NP ceased to be effective when TFEB was knocked down in PDLSCs. Our data demonstrate the crucial role of the autophagy-lysosome system in cellular osteogenesis under inflammatory conditions and suggest a new target for rescuing inflammation-induced cell dysfunction using nanomaterials to aid cell biology and tissue regeneration.

Metformin combats high glucose-induced damage to the osteogenic differentiation of human periodontal ligament stem cells via inhibition of the NPR3-mediated MAPK pathway.

BACKGROUND: High glucose-induced damage to the osteogenic differentiation of human periodontal ligament stem cells (PDLSCs) has long been a challenge to periodontal regeneration for diabetic individuals. Metformin is an anti-hyperglycemic drug that exhibits abundant biological activities associated with cell metabolism and downstream tissue regeneration. However, how metformin combats damage to PDLSC osteogenic differentiation under high glucose and the underlying mechanisms remain unknown. METHODS: Osteogenic differentiation of PDLSCs was assessed by alkaline phosphatase (ALP) staining, ALP activity, Alizarin Red staining and quantitative assay, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. RNA-seq analysis was performed to screen target genes of metformin, and the effects of target genes were confirmed using lentivirus transfection. Western blot analysis was also used to detect the protein level of underlying signaling pathways. RESULTS: We found that osteogenic differentiation of PDLSCs under high glucose was decreased, and metformin addition enhanced this capacity of differentiation. Furthermore, the results of RNA-seq analysis showed that natriuretic peptide receptor 3 (NPR3) was upregulated in PDLSCs under high glucose and downregulated after metformin addition. When the underlying pathways involved were investigated, we found that upregulation of NPR3 can compromise the metformin-enhanced PDLSC osteogenic differentiation and activate the MAPK pathway (especially the p38 MAPK and Erk1/2 pathway), and that inhibition of the NPR3-mediated p38 MAPK or Erk1/2 pathway enhanced the osteogenic differentiation of PDLSCs under high glucose. CONCLUSIONS: The present study suggests that metformin may enhance the osteogenic differentiation of PDLSCs under high glucose via downregulation of NPR3 and inhibition of its downstream MAPK pathway. This is the first report identifying the involvement of NPR3-mediated MAPK pathway in the metformin-enhanced osteogenic differentiation, indicating that NPR3 antagonists, such as metformin, may be feasible therapeutics for periodontal tissue regeneration in diabetic individuals.

Development of Unilateral Peri-Lead Edema Into Large Cystic Cavitation After Deep Brain Stimulation: A Case Report.

Background and Importance: Deep brain stimulation (DBS) has been approved to treat a variety of movement disorders, including Parkinson's disease (PD), essential tremor, and dystonia. Following the DBS surgery, some perioperative and even delayed complications due to intracranial and hardware-related events could occur, which may be life-threatening and require immediate remedial measures. Clinical Presentation: We report a case of an older woman with advanced PD who developed the unique complication of unilateral cyst formation at the tip of the DBS electrode after undergoing bilateral placement of subthalamic nucleus DBS. After a period of controlled motor symptoms, the patient showed new neurological deficits related to right peri-lead edema. However, the new neurological symptoms regressed quickly over several days with stereotactic implantation of a puncture needle to drain the cyst fluid without removing the affected lead. Conclusion: The occurrence of an intraparenchymal cyst following DBS surgery is a rare but life-threatening complication that could relate to edema around the electrodes or cerebrospinal fluid tracking. Stereotactic aspiration makes the intracranial cyst regress safely and effectively and ensures that the electrode is in the optimal position of the target nucleus to achieve an effective DBS surgery.

Periodontitis-compromised dental pulp stem cells secrete extracellular vesicles carrying miRNA-378a promote local angiogenesis by targeting Sufu to activate the Hedgehog/Gli1 signalling.

OBJECTIVES: Previously, our investigations demonstrated robust pro-angiogenic potentials of extracellular vesicles secreted by periodontitis-compromised dental pulp stem cells (P-EVs) when compared to those from healthy DPSCs (H-EVs), but the underlying mechanism remains unknown. MATERIALS AND METHODS: Here, circulating microRNAs (miRNAs) specifically found in P-EVs (compared with H-EVs) were identified by Agilent miRNA microarray analysis, and the roles of the candidate miRNA in P-EV-enhanced cell angiogenesis were confirmed by cell transfection and RNA interference methods. Next, the direct binding affinity between the candidate miRNA and its target gene was evaluated by luciferase reporter assay. CCK-8, transwell/scratch wound healing and tube formation assays were established to investigate the proliferation, migration, and tube formation abilities of endothelial cells (ECs). Western blot was employed to measure the protein levels of Hedgehog/Gli1 signalling pathway components and angiogenesis-related factors. RESULTS: The angiogenesis-related miRNA miR-378a was found to be enriched in P-EVs, and its role in P-EV-enhanced cell angiogenesis was confirmed, wherein Sufu was identified as a downstream target gene of miR-378a. Functionally, silencing of Sufu stimulated EC proliferation, migration and tube formation by activating Hedgehog/Gli1 signalling. Further, we found that incubation with P-EVs enabled the transmission of P-EV-contained miR-378a to ECs. Subsequently, the expressions of Sufu, Gli1 and vascular endothelial growth factor in ECs were significantly influenced by P-EV-mediated miR-378a transmission. CONCLUSIONS: These data suggest that P-EVs carrying miR-378a promote EC angiogenesis by downregulating Sufu to activate the Hedgehog/Gli1 signalling pathway. Our findings reveal a crucial role for EV-derived miR-378a in cell angiogenesis and hence offer a new target for modifying stem cells and their secreted EVs to enhance vessel regenerative potential.

Abnormal Spontaneous Neural Activity in Parkinson's Disease With "pure" Apathy.

BACKGROUND: Apathy is one of the most common non-motor symptoms of Parkinson's disease (PD). However, its pathophysiology remains unclear. METHODS: We analyzed resting-state functional magnetic resonance imaging (MRI) data acquired at a 3.0T MRI scanner using the amplitude of low-frequency fluctuation (ALFF) metric in 20 de novo, drug-naïve, non-demented PD patients with apathy (PD-A), 26 PD patients without apathy (PD-NA) without comorbidity of depressive or anxious symptoms, and 23 matched healthy control (HC) subjects. RESULTS: We found that the ALFF decreased significantly in the bilateral nucleus accumbens, dorsal anterior cingulate cortex (ACC), and left dorsolateral prefrontal cortex in patients with PD-A compared to patients with PD-NA and HC subjects. Furthermore, apathy severity was negatively correlated with the ALFF in the bilateral nucleus accumbens and dorsal ACC in the pooled patients with PD. CONCLUSION: The present study characterized the functional pattern of changes in spontaneous neural activity in patients with PD-A. With the aim to better elucidate the pathophysiological mechanisms responsible for these changes, this study controlled for the potentially confounding effects of dopaminergic medication, depression, anxiety, and global cognitive impairment. The findings of the current study add to the literature by highlighting potential abnormalities in mesocorticolimbic pathways involved in the development of apathy in PD.

Alterations of regional homogeneity in Parkinson's disease with "pure" apathy: A resting-state fMRI study.

BACKGROUND: Apathy is a prevalent and debilitating neuropsychiatric syndrome in Parkinson's disease (PD). However, its neural mechanisms are still unclear. METHODS: Forty-six de novo, drug-naïve, non-demented PD patients without depressive or anxious symptoms, of whom 26 were apathetic (PD-A) and 20 were not (PD-NA) according to the Apathy Scale (AS), and 23 matched healthy control (HC) subjects were enrolled in this study. The regional homogeneity (ReHo) approach based on resting-state functional MRI on a 3-T MR system was used to investigate apathy related local brain activity. RESULTS: Compared with both patients with PD-NA and HC subjects, patients with PD-A showed significantly lower ReHo values in the dorsal anterior cingulate cortex (ACC) and right caudate. Both the PD-A and PD-NA groups also demonstrated lower ReHo values in the right putamen compared to the HC group. Further correlation analyses revealed that AS scores were negatively correlated with the ReHo values in the dorsal ACC and right caudate in the pooled patients with PD. LIMITATIONS: The present results are preliminary due to the small sample size in the study. CONCLUSIONS: This study used ReHo for the first time to characterize "pure" apathy related regional spontaneous brain function within the frontostriatal circuits in PD. Our findings suggest that abnormal brain activity in the dorsal ACC and caudate may involve the pathological mechanisms of apathy in PD.

Building capacity for macrophage modulation and stem cell recruitment in high-stiffness hydrogels for complex periodontal regeneration: Experimental studies in vitro and in rats.

Recently, we found that although high-stiffness matrices stimulated osteogenic differentiation of bone marrow-derived stromal cells (BMSCs), the macrophages (Mφs) in high-stiffness transglutaminase crosslinked gelatins (TG-gels) tended to undergo M1 polarization and hence compromised cell osteogenesis. In this study, we hypothesized that the copresentation of interleukin (IL)-4 and stromal cell-derived factor (SDF)-1α in high-stiffness TG-gels may enhance periodontal regeneration by modulating Mφ polarization and promoting endogenous stem cell recruitment. We found that Mφs were more likely to polarize toward an immunomodulatory M2 state in the presence of IL-4 and hence positively influence the osteogenic differentiation of BMSCs when these cells coexisted in either indirect or direct co-culture systems. In cell migration assays, BMSCs exhibited an enhanced capability to move toward gels containing SDF-1α, and more cells could be recruited into the three-dimensional matrix of TG-gels. When TG-gels containing IL-4 and/or SDF-1α were used to repair periodontal defects, more new bone (MicroCT) was formed in animals that received the dual cytokine-loaded transplants at 4 weeks postsurgery. Mφs were recruited to all the transplanted gels, and after one week, more M1-phenotype cells were found in the groups without IL-4, while the presence of IL-4 was more likely to result in M2 polarization (immunofluorescence staining). When the tissue biopsies were histologically examined, the TG-gels containing both IL-4 and SDF-1α led to a generally satisfactory regeneration with respect to attachment recovery (epithelial and connective tissue) and hybrid tissue regeneration (bone, periodontal ligament and cementum). Our data suggest that the incorporation of IL-4 into high-stiffness TG-gels may promote the M2 polarization of Mφs and that SDF-1α can be applied to guide endogenous cell homing. Overall, building capacity for Mφ modulation and cell recruitment in high-stiffness hydrogels represents a simple and effective strategy that can support high levels of periodontal tissue regeneration. STATEMENT OF SIGNIFICANCE: The development of hydrogel-based regenerative therapies centered on the mobilization and stimulation of native cells for therapeutics opens a window toward realizing periodontal endogenous regeneration. In the present study, the parallel use of immunomodulatory and homing factors in high-stiffness hydrogel materials is shown to induce stem cell homing, modulate cell differentiation and indeed induce regrowth of the periodontium. We found that incorporation of interleukin (IL)-4 in high-stiffness TG-gels coaxed macrophages to polarize into M2 phenotypes, and stromal cell-derived factor (SDF)-1α could be applied to direct endogenous cell homing. Hence, we present for the first time a clinically relevant strategy based on macrophage modulation and host cell recruitment that can support high levels of periodontal tissue regeneration.

Concise Review: Periodontal Tissue Regeneration Using Stem Cells: Strategies and Translational Considerations.

Periodontitis is a widespread disease characterized by inflammation-induced progressive damage to the tooth-supporting structures until tooth loss occurs. The regeneration of lost/damaged support tissue in the periodontium, including the alveolar bone, periodontal ligament, and cementum, is an ambitious purpose of periodontal regenerative therapy and might effectively reduce periodontitis-caused tooth loss. The use of stem cells for periodontal regeneration is a hot field in translational research and an emerging potential treatment for periodontitis. This concise review summarizes the regenerative approaches using either culture-expanded or host-mobilized stem cells that are currently being investigated in the laboratory and with preclinical models for periodontal tissue regeneration and highlights the most recent evidence supporting their translational potential toward a widespread use in the clinic for combating highly prevalent periodontal disease. We conclude that in addition to in vitro cell-biomaterial design and transplantation, the engineering of biomaterial devices to encourage the innate regenerative capabilities of the periodontium warrants further investigation. In comparison to cell-based therapies, the use of biomaterials is comparatively simple and sufficiently reliable to support high levels of endogenous tissue regeneration. Thus, endogenous regenerative technology is a more economical and effective as well as safer method for the treatment of clinical patients. Stem Cells Translational Medicine 2019;8:392-403.

The role of DCs in the immunopathogenesis of chronic HBV infection and the methods of inducing DCs maturation.

Chronic hepatitis B virus (HBV) infection is the result of an inadequate immune response towards the virus. Dendritic cells (DCs), as the most efficient professional antigen-presenting cells (APCs), possess the strongest antigen presenting the effect in the body and can stimulate the initial T cell activation and proliferation. DCs of patients with chronic HBV infection are impaired, resulting in more tolerogenic rather than immunogenic responses, which may contribute to viral persistence. Recently, numerous methods have been developed to induce DCs maturation. To date, recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) combined with interleukin-4 (rhIL-4) has been a classic culture combination to DCs. The recently classified type III interferon group interferon-λ (IFN-λ) displays antiviral, antitumor, and immunoregulatory activity. In our laboratory, we demonstrate that IFN-λ1 combined with rhGM-CSF and rhIL-4 can significantly increase the expression of DC surface molecules and the secretion of interleukin-12 (IL-12) and interferon-γ (IFN-γ) in patients with chronic hepatitis B infection. In this review, we emphasize on the role of DCs in the immunopathogenesis of chronic HBV infection. Importantly, we systematic review that the latest update in the current status of knowledge on the methods of inducing DCs maturation in anti-HBV immunity. What's more, we conclude that IFN-λ1 combined with GM-CSF and IL-4 can induce DCs maturation, which could become a possibility to be applied to the autologus dendritic cell vaccine to treat chronic hepatitis B.

Modulation of the function of dendritic cells in adolescents with chronic HBV infection by IFN-λ1.

The exact immunology pathogenesis of hepatitis B virus (HBV) infection remains unclear currently. The dendritic cells (DCs) dysfunction is evident in adolescents with chronic HBV infection in the immune tolerant phase. DCs, as the most efficient professional antigen-presenting cells (APCs), possess the strongest antigen presenting the effect in the body and can stimulate the initial T cell activation and proliferation, depending on their stage of maturation. The recently classified type III interferon group, interferon-λ1 (IL-29), interferon-λ2 (IL-28A), and interferon-λ3 (IL-28B) displays immunomodulatory and antiviral activity. In the current study, we describe a way to stimulate the DCs maturation. As a result, IFN-λ1 combined with recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) and recombinant human interleukin-4 (rhIL-4) can induce the DCs maturation and promote the costimulatory molecules such as CD80, CD83, CD86 and human leucocyte antigen DR (HLA-DR) expression in the immune tolerance and the clearance phases. This study demonstrates that the DCs function is remarkably impaired both in the immune tolerant phase and the immune clearance phase in adolescents with chronic HBV infection compared with healthy youth control. At the same time, this study has developed a theoretical basis for the application of IFN-λ1 breaking immune tolerance and improving the body's immune system to clear HBV.

Investigation of dental pulp stem cells isolated from discarded human teeth extracted due to aggressive periodontitis.

Recently, human dental pulp stem cells (DPSCs) isolated from inflamed dental pulp tissue have been demonstrated to retain some of their pluripotency and regenerative potential. However, the effects of periodontal inflammation due to periodontitis and its progression on the properties of DPSCs within periodontally compromised teeth remain unknown. In this study, DPSCs were isolated from discarded human teeth that were extracted due to aggressive periodontitis (AgP) and divided into three experimental groups (Groups A, B and C) based on the degree of inflammation-induced bone resorption approaching the apex of the tooth root before tooth extraction. DPSCs derived from impacted or non-functional third molars of matched patients were used as a control. Mesenchymal stem cell (MSC)-like characteristics, including colony-forming ability, proliferation, cell cycle, cell surface antigens, multi-lineage differentiation capability and in vivo tissue regeneration potential, were all evaluated in a patient-matched comparison. It was found that STRO-1- and CD146-positive DPSCs can be isolated from human teeth, even in very severe cases of AgP. Periodontal inflammation and its progression had an obvious impact on the characteristics of DPSCs isolated from periodontally affected teeth. Although all the isolated DPSCs in Groups A, B and C showed decreased colony-forming ability and proliferation rate (P < 0.05), the decreases were not consistent with the degree of periodontitis. Furthermore, the cells did not necessarily show significantly diminished in vitro multi-differentiation potential. Only DPSCs from Group A and the Control group formed dentin-like matrix in vivo when cell-seeded biomaterials were transplanted directly into an ectopic transplantation model. However, when cell-seeded scaffolds were placed in the root fragments of human teeth, all the cells formed significant dentin- and pulp-like tissues. The ability of DPSCs to generate dental tissues decreased when the cells were isolated from periodontally compromised teeth (P < 0.05). Again, increased periodontal destruction was not necessarily followed by a decrease in the amount of dentin- and pulp-like tissue formed. These findings provide preliminary evidence that periodontally compromised teeth might contain putative stem cells with certain MSC properties, as long as the vitality of the pulp has not been totally damaged. Whether these cells can serve as a source of autologous multipotent MSCs for clinical regenerative therapies warrants further investigation with larger sample sizes and various types of periodontitis.

Stem cell-delivery therapeutics for periodontal tissue regeneration.

Periodontitis, an inflammatory disease, is the most common cause of tooth loss in adults. Attempts to regenerate the complex system of tooth-supporting apparatus (i.e., the periodontal ligament, alveolar bone and root cementum) after loss/damage due to periodontitis have made some progress recently and provide a useful experimental model for the evaluation of future regenerative therapies. Concentrated efforts have now moved from the use of guided tissue/bone regeneration technology, a variety of growth factors and various bone grafts/substitutes toward the design and practice of endogenous regenerative technology by recruitment of host cells (cell homing) or stem cell-based therapeutics by transplantation of outside cells to enhance periodontal tissue regeneration and its biomechanical integration. This shift is driven by the general inability of conventional therapies to deliver satisfactory outcomes, particularly in cases where the disease has caused large tissue defects in the periodontium. Cell homing and cell transplantation are both scientifically meritorious approaches that show promise to completely and reliably reconstitute all tissue and connections damaged through periodontal disease, and hence research into both directions should continue. In view of periodontal regeneration by paradigms that unlock the body's innate regenerative potential has been reviewed elsewhere, this paper specifically explores and analyses the stem cell types and cell delivery strategies that have been or have the potential to be used as therapeutics in periodontal regenerative medicine, with particular emphasis placed on the efficacy and safety concerns of current stem cell-based periodontal therapies that may eventually enter into the clinic.

The effects of human platelet lysate on dental pulp stem cells derived from impacted human third molars.

Human platelet lysate (PL) has been suggested as a substitute for fetal bovine serum (FBS) in the large-scale expansion of dental pulp stem cells (DPSCs). However, the biological effects and the optimal concentrations of PL for the proliferation and differentiation of human DPSCs remain unexplored. We isolated and expanded stem cells from the dental pulp of extracted third molars and evaluated the effects of PL on the cells' proliferative capacity and differentiation potential in vitro and in vivo. Before testing, immunocytochemical staining and flow cytometry-based cell sorting showed that the cells derived from human dental pulp contained mesenchymal stem cell populations. Cells were grown on tissue culture plastic or on hydroxyapatite-tricalcium phosphate (HA/TCP) biomaterials and were incubated with either normal or odontogenic/osteogenic media in the presence or absence of various concentrations of human PL for further investigation. The proliferation of DPSCs was significantly increased when the cells were cultured in 5% PL under all testing conditions (P < 0.05). However, this enhancement was inconsistent when the cells were cultured in 1% PL or in 10% PL; 10% PL significantly inhibited cell proliferation and was therefore excluded from further differentiation testing. Culture medium containing 5% PL also significantly promoted the mineralized differentiation of DPSCs, as indicated by the measurement of alkaline phosphatase activity and calcium deposition under mineral-conditioned media (P < 0.05). Scanning electron microscopy and modified Ponceau trichrome staining showed that the cells treated with 5% PL and mineralizing media were highly capable of integrating with the HA/TCP biomaterials and had fully covered the surface of the scaffold with an extensive sheet-like structure 14 d after seeding. In addition, 5% PL showed significantly positive effects on tissue regeneration in two in vivo transplantation models. We conclude that the appropriate concentration of PL enhances the proliferation and mineralized differentiation of human DPSCs both in vitro and in vivo, which supports the use of PL as an alternative to FBS or a nonzoonotic adjuvant for cell culture in future clinical trials. However, the elucidation of the molecular complexity of PL products and the identification of both the essential growth factors that determine the fate of a specific stem cell and the criteria to establish dosing require further investigation.

Designing biomaterials for in situ periodontal tissue regeneration.

The regeneration of periodontal tissue poses a significant challenge to biomaterial scientists, tissue engineers and periodontal clinicians. Recent advances in this field have shifted the focus from the attempt to recreate tissue replacements/constructs ex vivo to the development of biofunctionalized biomaterials that incorporate and release regulatory signals in a precise and near-physiological fashion to achieve in situ regeneration. The molecular and physical information coded within the biomaterials define a local biochemical and mechanical niche with complex and dynamic regulation that establishes key interactions with host endogenous cells and, hence, may help to unlock latent regenerative pathways in the body by instructing cell homing and regulating cell proliferation/differentiation. In the future, these innovative principles and biomaterial devices promise to have a profound impact on periodontal reconstructive therapy and are also likely to reconcile the clinical and commercial pressures on other tissue engineering endeavors.

Effects of prostaglandin E1 on perihematomal tissue after hypertensive intracerebral hemorrhage.

PURPOSE: To observe the effects of Prostaglandin E1 (PGE1) on hematoma, perihematomal tissue and the impairment of neurological function in patients with hypertensive intracerebral hemorrhage (HICH). METHODS: A total of 40 patients with HICH were enrolled according to the inclusion criteria and randomly divided into two groups: the control group (n=20) and the PGE1 treatment group (n=20). In each group, 99mTc-ethyl cysteinate dimer (ECD) SPECT brain perfusion imaging was performed on days 5 and 20 after stroke, and the regional cerebral blood flow of the hematoma area, the proximal and distal regions of the hematoma surrounding tissue and the frontal and parietal lobe areas were calculated with semiquantitative methods (the Ra value was shown as an uptake ratio). The volumes of hematoma and perihematomal tissue of the subjects (low-density areas around the hematoma as observed in the skull CT) were recorded by skull CT scan. Meanwhile, the NIHSS score for each patient was assessed upon admission and on the 5th, 12th, and 20th days of hospital stay. The mRS scores of each patient were recorded on the 1st and 20th days of admission. The NIHSS and mRS assessments were also performed three months following admission. RESULTS: In the PGE1 treatment group, the Ra values of the proximal and distal regions of the perihematomal tissue were significantly higher than those in prior treatment, and were significantly higher than the values in control group. The Ra values in the frontal and parietal lobes showed no significant differences before and after treatment. The volumes of hematomas in the PGE1 group were obviously reduced on the 12th and 20th days when compared with the 1st day and the 5th day, and these differences showed statistical significance. The volumes of hematomas in the control group were obviously reduced on the 20th when compared with the 1st day. On the 20th day, volumes of hematomas were significantly reduced in the PGE1 group than in control group . Moreover, the volume of perihematomal tissue in the PGE1 group was significantly reduced on the 20th day when compared with on the 5th day and the control group. NIHSS scores showed statistically significant differences on the 20th day of admission and the follow-up three months later when the PGE1 treatment group and control group were compared. mRS scores in the three-month follow-up also showed statistically significant differences between the two groups . CONCLUSION: The application of PGE1 therapy for patients with hypertensive intracerebral hemorrhage started on the 5th day after stroke was capable of enhancing rCBF of perihematomal tissue. This treatment significantly improved the prognosis of and recovery from neurological deficits in HICH patients.