ULK1-regulated AMP sensing by AMPK and its application for the treatment of chronic kidney disease.

Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a central kinase involved in energy homeostasis. Increased intracellular AMP levels result in AMPK activation through the binding of AMP to the γ-subunit of AMPK. Recently, we reported that AMP-induced AMPK activation is impaired in the kidneys in chronic kidney disease (CKD) despite an increase in the AMP/ATP ratio. However, the mechanisms by which AMP sensing is disrupted in CKD are unclear. Here, we identified mechanisms of energy homeostasis in which Unc-51-like kinase 1 (ULK1)-dependent phosphorylation of AMPKγ1 at Ser260/Thr262 promoting AMP sensitivity of AMPK. AMPK activation by AMP was impaired in Ulk1 knockout mice despite an increased AMP/ATP ratio. ULK1 expression is markedly downregulated in CKD kidneys, leading to AMP sensing failure. Additionally, MK8722, an allosteric AMPK activator, stimulated AMPK in the kidneys of a CKD mouse model (5/6th nephrectomy) via a pathway that is independent of AMP sensing. Thus, our study shows that MK8722 treatment significantly attenuates the deterioration of kidney function in CKD and may be a potential therapeutic option in CKD therapeutics.

Lipid Peroxidation Regulators GPX4 and FSP1 as Prognostic Markers and Therapeutic Targets in Advanced Gastric Cancer.

Gastric cancer is one of the most common cancers worldwide, and new therapeutic strategies are urgently needed. Ferroptosis is an intracellular iron-dependent cell death induced by the accumulation of lipid peroxidation, a mechanism different from conventional apoptosis and necrosis. Therefore, induction of ferroptosis is expected to be a new therapeutic strategy. Glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1) have been identified as the major inhibitors of ferroptosis. Herein, we performed immunohistochemistry for GPX4, FSP1, and 4-HNE using tissues from patients with gastric cancer and investigated the relationship between these factors and prognosis. Patients with high GPX4 expression or high GPX4 expression and low 4-HNE accumulation tended to have a poor prognosis (p = 0.036, 0.023), whereas those with low FSP1 expression and high 4-HNE accumulation had a good prognosis (p = 0.033). The synergistic induction of cell death by inhibiting GPX4 and FSP1 in vitro was also observed, indicating that the cell death was non-apoptotic. Our results indicate that the expression and accumulation of lipid peroxidation-related factors play an important role in the clinicopathological significance of gastric cancer and that novel therapeutic strategies targeting GPX4 and FSP1 may be effective in treating patients with gastric cancer who have poor prognosis.

Prognostic Impact and Genomic Backgrounds of Renal Parenchymal Infiltration or Micronodular Spread in Nonmetastatic Clear Cell Renal Cell Carcinoma.

A subset of clear cell renal cell carcinomas (ccRCCs) exhibits various growth patterns that infiltrate the normal renal parenchyma; however, our understanding of its association with cancer aggressiveness is incomplete. Here, we show that the morphology of the tumor interface with normal renal parenchyma is robustly associated with cancer recurrence after surgery, even when compared with the TNM staging system or the World Health Organization/International Society of Urological Pathology (WHO/ISUP) nuclear grade in nonmetastatic ccRCC. Hematoxylin and eosin-stained slides of whole tissue sections from surgical specimens were analyzed using a cohort of 331 patients with nonmetastatic ccRCC treated with radical nephrectomy. The patients were classified into 10 subgroups based on our classification algorithms for assessing the tumor interface with normal renal parenchyma. Among the 10 subgroups, 4 subgroups consisting of 40 patients (12%) were identified to have aggressive forms of nonmetastatic ccRCC associated with poor prognosis and unified as renal parenchymal infiltration or micronodular spread (RPI/MNS) phenotypes. Multivariable analyses showed that RPI/MNS phenotypes were robustly associated with shorter disease-free survival, independently of existing pathological factors including the TNM staging system and WHO/ISUP nuclear grade. The hazard ratio was highest for RPI/MNS (4.62), followed by WHO/ISUP grades 3 to 4 (2.11) and ≥pT3a stage (2.05). In addition, we conducted genomic analyses using next-generation sequencing of infiltrative lesions in 18 patients with RPI/MNS and tumor lesions in 33 patients without RPI/MNS. Results showed that alterations in SETD2 and TSC1 might be associated with RPI/MNS phenotypes, whereas alterations in PBRM1 might be associated with non-RPI/MNS phenotypes. These data suggest that RPI/MNS may be associated with aggressive genomic backgrounds of ccRCC, although more comprehensive analyses with a larger sample size are required. Future studies may further elucidate the clinical implications of RPI/MNS, particularly for deciding the indication of adjuvant treatment after nephrectomy.

Case report: Pathological differences in pulmonary arterial hypertension in long-term responders to calcium channel blockers.

Background: This study investigates the pulmonary arterial histopathology in patients with idiopathic pulmonary arterial hypertension (IPAH) and acute vasoreactive phenotype, who demonstrated long-term survival (>30 years) and incidental death from causes other than PAH progression. The pathological changes observed in these patients were compared with those in patients with bone morphogenetic protein receptor type 2 (BMPR2) mutation. Case Presentation: We present two cases of patients with pulmonary arterial hypertension (PAH) who died incidentally from causes unrelated to PAH progression. We report compares pulmonary arterial histopathology in long-term survivors of CCB-responsive PAH patient and a hereditary PAH patient with a BMPR2 mutation. Lung specimens were analyzed using the Heath and Edwards (HE) classification and percentage muscular wall thickness (%MWT) of pulmonary arterioles. A significant difference in the severity of grading (p = 0.0001) and distribution between grades 1-2, 4 (p = 0.001), and 5 (p = 0.014) was observed between both patients. These findings suggest differential vascular pathology between the two cases, with CCB responders displaying more mild illness lesions compared to BMPR2 mutant patients. Conclusion: The study revealed that CCB responders exhibit more mild illness vascular lesions than BMPR2 mutant patients despite their long-term survival, suggesting a difference in vascular pathology between the two phenotypes.

Invasive features of superficial oesophageal squamous cell carcinoma-analysis of risk factors for lymph node metastasis.

There are currently no studies that have examined the clinicopathological factors in detail, including the histological images of the invasive front, and the risk of lymph node metastasis (LNM) in superficial oesophageal squamous cell carcinoma (SESCC). This study aimed to develop an algorithm that contributes to a better assessment of the risk of LNM and recurrence in SESCC. Clinicopathological factors, such as submucosal (SM) invasion distance, were examined in 88 surgically resected cases of SESCC. An SM invasion distance of 600 µm was the statistically best customer value for LNM (p = 0.0043). To obtain a histological image of the invasive front, we evaluated modified tumour budding (MBD) by modifying the number of tumour foci constituent cells and foci in tumour budding. We also evaluated the smallest number of tumour foci. Using these factors, we developed an algorithm to predict the risk of LNM. The best algorithm was created using an SM invasion distance of 600 µm and an index of 5 or more foci consisting of five or fewer tumour cells in the MBD (MBD5 high-grade ≥ 5), which was also significantly associated with recurrence-free survival (p = 0.0305). Further study of the algorithm presented in this study is expected to improve the quality of life of patients by selecting appropriate additional treatments after endoscopic resection and appropriate initial treatment for SESCC.

Prospective screening for myocarditis in cancer patients treated with immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) improve clinical outcomes in various cancers, but sometimes induce autoimmune adverse effects, including myocarditis, which is the most serious complication. There are many reports on ICI-induced myocarditis; however, only a few prospective surveillance reports exist. Therefore, we developed a prospective screening protocol and performed monitoring clinically suspected myocarditis in every patient treated with ICIs. METHODS: We prospectively enrolled 126 consecutive patients treated with ICIs in this cohort. Outcomes of patients were determined and analyzed between April 2017 and May 2020. We evaluated vital signs, biomarkers, electrocardiograms, chest radiographs, and echocardiographs before and at 7 ±â€¯3, 14 ±â€¯3, 21 ±â€¯3, and 60 ±â€¯7 days after ICI initiation. RESULTS: Eighteen (14.3 %) presented troponin I elevation and 13 of them presented signs of clinically suspected myocarditis (10.3 %). Among the 13 patients, ICI was discontinued in four cases (3.2 %) without fatal events. Myocarditis appeared at an early stage of ICI treatment, regardless of severity (median, 44 days). CONCLUSIONS: We observed the frequency of patients with myocarditis or myocardial damage through a prospective screening program in the real world. Although the frequency was higher than expected, most cases were mild and ICI treatment could be continued under careful observation.

Immunohistochemical Differentiation between Western and East Asian Types of CagA-Positive Helicobacter pylori in Gastric Biopsy Samples.

Background: Cag A-positive Helicobacter pylori isolated from human gastric mucosa is categorized as a Western or East Asian allele-type based on whether the cagA gene encodes an EPIYA-C or EPIYA-D motif. We aimed to differentiate between the 2 types of H. pylori by immunohistochemistry (IHC) using formalin-fixed paraffin-embedded (FFPE) gastric biopsy samples. Materials and Methods: We developed 2 monoclonal antibodies (mAbs) that detect either the EPIYA-C or EPIYA-D motif of the H. pylori CagA protein by IHC using FFPE tissues. FFPE tissue sections from 30 Japanese and 39 Brazilian gastric biopsy samples with H. pylori infection confirmed by Giemsa staining (moderate/severe in the Sydney classification system) were examined by IHC with the novel mAbs followed by polymerase chain reaction (PCR) for EPIYA-C or EPIYA-D using DNA extracted from adjacent tissue sections. Results: Differentiation among Western and East Asian types and CagA-negative H. pylori was successful in most (97%) samples by IHC with the novel mAbs and commercially available mAbs that react with a species-specific lipopolysaccharide or a common CagA motif of H. pylori. The detection status of EPIYA-C/D motifs by IHC with the novel mAbs was consistent with the PCR results in 61 (88%) of 69 samples: EPIYA-C(+)/D(-) in zero Japanese and 26 Brazilian samples, EPIYA-C(-)/D(+) in 26 Japanese and 1 Brazilian sample, and EPIYA-C(-)/D(-) in 1 Japanese and 7 Brazilian samples. The detection sensitivity and specificity of IHC with each novel mAb compared with the PCR results were, respectively, 84% and 97% for EPIYA-C, and 97% and 95% for EPIYA-D. Conclusions: The novel mAbs specific to each EPIYA-C or EPIYA-D motif differentiated between Western and East Asian types of CagA-positive H. pylori by IHC using FFPE tissues. Applying these novel mAbs to large numbers of archived pathology samples will contribute to elucidating the association of these allele types with gastric cancer.

Usefulness of Global Longitudinal Strain-Guided Management in Preventing Human Epidermal Growth Factor Receptor 2 (HER2) Inhibitor-Induced Myocardial Damage.

Background: Trastuzumab, an anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibody, is a specific first-line treatment for patients with HER2-positive cancers. Cardiac dysfunction is among the most problematic adverse events associated with trastuzumab. Although regular echocardiographic screening is recommended for early detection of cardiac damage, few reports have investigated the validity of echocardiographic screening in chemotherapy. Therefore, the aim of this study was to determine whether a GLS-guided management approach could reduce cardiotoxicity and discontinuation of trastuzumab chemotherapy. Methods and Results: To evaluate the usefulness of global longitudinal strain (GLS)-guided cardioprotective interventions, we retrospectively analyzed 67 patients treated with trastuzumab who underwent structured echocardiographic assessments before and after 1, 3, and 6 courses of trastuzumab administration. If a >15% relative decrease in GLS was identified, cardioprotective agents were administered. Thirty (44.8%) patients had breast cancer; the remaining patients had salivary gland cancer. The median observation period for the intervention group was 304 days from the initial evaluation. Nineteen (28.4%) patients exhibited a >15% relative decrease in GLS, and consequently received cardioprotective agents. The incidence of trastuzumab discontinuation for cardiogenic reasons was significantly lower among patients receiving GLS-guided interventions than among those not receiving the intervention (2.4% vs. 24.0%; P=0.009). The incidence of a subsequent decline in left ventricular ejection fraction was lower among patients receiving the intervention than among those not receiving the intervention (4.8% vs. 24.0%; P=0.04). Conclusions: GLS-guided cardioprotective intervention significantly decreased the incidence of trastuzumab discontinuation.

PHOX2B is a Sensitive and Specific Marker for the Histopathological Diagnosis of Pheochromocytoma and Paraganglioma.

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are non-epithelial neuroendocrine neoplasms originating from the adrenal medulla and paraganglion of the sympathetic and parasympathetic nervous system, respectively. PCCs and PGLs show histological similarities with other epithelial neuroendocrine neoplasms and olfactory neuroblastomas (ONBs), and the differential diagnosis of PGLs is particularly difficult. Therefore, we compared the sensitivity of PHOX2A, PHOX2B, and tyrosine hydroxylase (TH) in the histopathological diagnosis of PCCs and PGLs immunohistochemically using the tissue microarrays of 297 neoplasms including PCCs, PGLs, neuroblastomas, ganglioneuromas, epithelial neuroendocrine neoplasms, and ONBs. Using cutoff values of 25%, 5%, and 5% of tumor cells expressing PHOX2A, PHOX2B, and TH, respectively, as positive, 40 of 51 PCCs, 32 of 33 parasympathetic/head and neck PGLs (HNPGLs), 17 of 19 sympathetic/thoracoabdominal PGLs (TAPGLs), and 12 of 152 epithelial neuroendocrine neoplasms, including 123 well-differentiated and 29 poorly differentiated neuroendocrine neoplasms, were PHOX2A-positive. All 51 PCCs, 33 HNPGLs, and 19 TAPGLs were PHOX2B-positive, while all 152 epithelial neuroendocrine neoplasms were PHOX2B-negative. Moreover, 50 of 51 PCCs, 13 of 33 HNPGLs, all TAPGLs, and 12 of 152 epithelial neuroendocrine neoplasms were TH-positive. All ONBs were negative for PHOX2A, PHOX2B, and TH. PHOX2B was the most sensitive and specific diagnostic marker for PCCs and PGLs among PHOX2A, PHOX2B, and TH. PHOX2B can facilitate identification of PCCs and PGLs from epithelial neuroendocrine neoplasms and ONBs, especially in the case of HNPGLs, in which TH is often negative.

Long-term safety of a structured transition protocol from parenteral prostanoids to selexipag in pulmonary arterial hypertension.

There was no structured method for safely transition from parenteral prostanoids to oral medication. We enrolled 37 idiopathic/hereditary pulmonary arterial hypertension patients receiving triple combination therapy including parenteral prostanoids into structured transition program to oral selexipag. Four (10.8%) patients successfully transitioned under the protocol, and all of them presented long-term safety.

Liver fibrosis index as a novel prognostic factor in patients with pulmonary arterial hypertension.

Liver dysfunction is an important determinant of the prognosis of left heart failure patients. However, few studies have reported on cardiohepatic interactions in right heart failure patients, a condition that is an important prognostic factor in pulmonary arterial hypertension (PAH). This study aimed to evaluate the existence and extent of hepatic fibrosis and its contribution as a prognostic factor in PAH. This prospective study enrolled 60 consecutive patients with PAH in the International University of Health and Welfare Mita Hospital from June 2016 to December 2017. After the application of the exclusion criteria, 35 patients were assessed for hepatic fibrosis, using real-time tissue elastography, and for clinical deterioration. Sixteen healthy controls were also assessed for comparison. The liver fibrosis index (LFI) was significantly higher in PAH patients than in healthy controls (1.214 ± 0.047 vs. 0.911 ± 0.059, P < 0.001), suggesting that PAH patients exhibited mild liver fibrosis. However, patients with deterioration (vs. no deterioration) had significantly higher LFI values (1.507 ± 0.078 vs. 1.080 ± 0.034, P < 0.001), independent from other established liver function parameters. A receiver operating characteristic curve analysis identified that an LFI ≥ 1.275 indicated a significant probability of clinical deterioration (hazard ratio: 8.4 (95% CI 1.5-45.4, P = 0.012), independent from other known PAH prognostic factors. PAH patients may exhibit subclinical liver fibrosis associated with chronic right heart failure. The LFI can serve as both a non-invasive evaluation of liver fibrosis and a predictive marker for the deterioration of PAH patients.

Propionibacterium acnes-Derived Circulating Immune Complexes in Sarcoidosis Patients.

Propionibacterium acnes is a potential etiologic agent of sarcoidosis and a dysregulated immune response to the commensal bacterium is suspected to cause granuloma formation. P. acnes-derived insoluble immune complexes were recently demonstrated in sinus macrophages of sarcoidosis lymph nodes, suggesting local proliferation of the bacterium in affected organs. In the present study, we developed a method for detecting P. acnes-derived immune complexes in human blood by measuring the concentration of P. acnes-specific lipoteichoic acid (PLTA) detectable after an antigen retrieval pretreatment of plasma samples. Before pretreatment, anti-PLTA antibody was detected and PLTA could not be detected, in all plasma samples from 51 sarcoidosis patients and 35 healthy volunteers. After pretreatment, however, a significant level of PLTA (>105 ng/mL) was detected in 33 (65%) sarcoidosis patients and 5 (14%) control subjects, with 86% specificity and 65% sensitivity for sarcoidosis. In both groups, plasma anti-PLTA antibody titers did not differ between samples with and without detection of PLTA. PLTA levels were abnormally increased (>202 ng/mL) in 21 (41%) sarcoidosis patients. These findings suggest that P. acnes-derived circulating immune complexes present in human blood are abnormally increased in many sarcoidosis patients, presumably due to local proliferation of the bacterium in the affected organs.

Case Report: BMPR2-Targeted MinION Sequencing as a Tool for Genetic Analysis in Patients With Pulmonary Arterial Hypertension.

Background: Mutations in the bone morphogenetic protein receptor type 2 gene (BMPR2) represent a major genetic cause of pulmonary arterial hypertension (PAH). Identification of BMPR2 mutations is crucial for the genetic diagnosis of PAH. MinION nanopore sequencer is a portable third-generation technology that enables long-read sequencing at a low-cost. This nanopore technology-based device has not been used previously for PAH diagnosis. This study aimed to determine the feasibility of using MinION nanopore sequencing for the genetic analysis of PAH patients, focused on BMPR2. Methods: We developed a protocol for the custom bioinformatics pipeline analysis of long reads generated by long-PCR. To evaluate the potential of using MinION sequencing in PAH, we analyzed five samples, including those of two idiopathic PAH patients and a family of three members with one affected patient. Sanger sequencing analysis was performed to validate the variants. Results: The median read length was around 3.4 kb and a good mean quality score of approximately 19 was obtained. The total number of reads generated was uniform among the cases and ranged from 2,268,263 to 3,126,719. The coverage was consistent across flow cells in which the average number of reads per base ranged from 80,375 to 135,603. We identified two polymorphic variants and three mutations in four out of five patients. Certain indel variant calling-related errors were observed, mostly outside coding sequences. Conclusion: We have shown the ability of this portable nanopore sequencer to detect BMPR2 mutations in patients with PAH. The MinION nanopore sequencer is a promising tool for screening BMPR2 mutations, especially in small laboratories and research groups.

Pulmonary hypertension associated with neurofibromatosis type 2.

Although precapillary pulmonary hypertension is a rare but severe complication of patients with neurofibromatosis type 1 (NF1), its association with NF2 remains unknown. Herein, we report a case of a 44-year-old woman who was initially diagnosed with idiopathic pulmonary arterial hypertension and treated with pulmonary arterial hypertension-specific combination therapy. However, a careful assessment for a relevant family history of the disease and genetic testing reveal that this patient had a mutation in the NF2 gene. Using immunofluorescence and Western blotting, we demonstrated a decrease in endothelial NF2 protein in lungs from idiopathic pulmonary arterial hypertension patients compared to control lungs, suggesting a potential role of NF2 in pulmonary arterial hypertension development. To our knowledge, this is the first time that precapillary pulmonary hypertension has been described in a patient with NF2. The altered endothelial NF2 expression pattern in pulmonary arterial hypertension lungs should stimulate work to better understand how NF2 is contributing to the pulmonary vascular remodelling associated to these severe life-threatening conditions.

Explainable Artificial Intelligence Model for Diagnosis of Atrial Fibrillation Using Holter Electrocardiogram Waveforms.

Atrial fibrillation is a clinically important arrhythmia. There are some reports on machine learning models for AF diagnosis using electrocardiogram data. However, few reports have proposed an eXplainable Artificial Intelligence (XAI) model to enable physicians to easily understand the machine learning model's diagnosis results.We developed and validated an XAI-enabled atrial fibrillation diagnosis model based on a convolutional neural network (CNN) algorithm. We used Holter electrocardiogram monitoring data and the gradient-weighted class activation mapping (Grad-CAM) method.Electrocardiogram data recorded from patients between January 4, 2016, and October 31, 2019, totaling 57,273 electrocardiogram waveform slots of 30 seconds each with diagnostic information annotated by cardiologists, were used for training our proposed model. Performance metrics of our AI model for AF diagnosis are as follows: sensitivity, 97.1% (95% CI: 0.969-0.972); specificity, 94.5% (95% CI: 0.943-0.946); accuracy, 95.3% (95% CI: 0.952-0.955); positive predictive value, 89.3% (95% CI: 0.892-0.897); and F-value, 93.1% (95% CI: 0.929-0.933). The area under the receiver operating characteristic curve for AF detection using our model was 0.988 (95% CI: 0.987-0.988). Furthermore, using the XAI method, 94.5 ± 3.5% of the areas identified as regions of interest using our machine learning model were identified as characteristic sites for AF diagnosis by cardiologists.AF was accurately diagnosed and favorably explained with Holter ECG waveforms using our proposed CNN-based XAI model. Our study presents another step toward realizing a viable XAI-based detection model for AF diagnoses for use by physicians.

Pathological and immunological differences of arterial thrombi and wall caused by three different periodontal bacterial injections in rat models and proposals on the pathogeneses of vascular diseases.

OBJECTIVES: Periodontal bacteria that have been studied show a strong connection to various vascular diseases. Among the many kinds of periodontal bacteria, Porphyromonas gingivalis (Pg) is well examined in the general aspects and in a rat model. However, whether other periodontal bacteria work or react differently is not studied well. MATERIAL AND METHODS: We chose Aggregatibacter actinomycetemcomitans (Aa) and Prevotella intermedia (Pi) as different types of periodontal bacteria. Low-density and high-density bacterial solutions were injected in the small artery of rats' groins using our rat model. Eighteen limbs of 9 SD male rats (500-650 g) were used. After 7 days, 14-18 days, and 28 days, the rats were sacrificed. A pathological and an immuno-histochemical study was conducted and reported on the low-density group with 12 limbs because the Pi group lacked a high-density study. Immuno-histochemical staining of live Pg was performed on three limbs of three rats at 1 h, 3 h, and 1 week after injection. RESULTS: The appearances from the acute, at 7 days, to chronic phases, at 28 days, were observed. The differences of the species were certainly observed in the internal elastic lamina (IEL), and immuno-histochemical reactions. The inflammatory reactions, such as cellular distribution or intra-thrombus materials, were similar in all. One week later, we could not see any living bacteria in the specimen or immunological observation. CONCLUSIONS: The three species were essentially the same, except for Aa's stronger disruption of IEL, and more CD3 (Pan T cell) in Pi and more CD79a (Pan B cell) in Pg. We propose a new concept of a possible mechanism of vascular diseases, in which the work of LPS (lipopolysaccharides) and a toll-like receptor (TLR) is emphasized.

How COVID-19 Affected the Introduction of Telemedicine and Patient Reported Outcomes Among Patients With Pulmonary Hypertension　- A Report From a Referral Center in Japan.

Background: COVID-19 is fatal to patients with pulmonary hypertension (PH), so preventive actions are recommended. This study investigated the effectiveness of telemedicine and effects on quality of life (QOL) in the treatment of patients with PH. Methods and Results: Japanese patients with PH (n=40) were recruited from one referral center. Patient self-reported anxiety worsened significantly and elderly patients in particular experienced detrimental lifestyle changes under COVID-19. Telemedicine worked well to decrease the frequency of going out. Conclusions: Telemedicine is effective in reducing travel distances, and frequent remote interventions may be desirable for older, anxious patients.

Catalase expression of Propionibacterium acnes may contribute to intracellular persistence of the bacterium in sinus macrophages of lymph nodes affected by sarcoidosis.

Bacterial catalase is important for intracellular survival of the bacteria. This protein of Propionibacterium acnes, one of possible causes of sarcoidosis, induces hypersensitive Th1 immune responses in sarcoidosis patients. We examined catalase expression in cultured P. acnes isolated from 19 sarcoid and 18 control lymph nodes and immunohistochemical localization of the protein in lymph nodes from 43 sarcoidosis and 102 control patients using a novel P. acnes-specific antibody (PAC) that reacts with the catalase protein, together with the previously reported P. acnes-specific PAB and TIG antibodies. High catalase expression of P. acnes cells was found during stationary phase in more isolates from sarcoid than from non-sarcoid lymph nodes and was associated with bacterial survival under H2O2-induced oxidative stress. In many sarcoid and some control lymph nodes, catalase expression was detected at the outer margins of PAB-reactive Hamazaki-Wesenberg (HW) bodies in sinus macrophages, the same location as catalase expression on the surface of cultured P. acnes and the same distribution as bacterial cell membrane-bound lipoteichoic acid in HW bodies. Some or no catalase expression was detected in sarcoid granulomas with PAB reactivity or in clustered paracortical macrophages packed with many PAB-reactive small-round bodies. HW bodies expressing catalase may be persistent P. acnes in sinus macrophages whereas PAB-reactive small-round bodies with undetectable catalase may be activated P. acnes proliferating in paracortical macrophages. Intracellular proliferation of P. acnes in paracortical macrophages may lead to granuloma formation by this commensal bacterium in sarcoidosis patients with Th1 hypersensitivity to certain P. acnes antigens, including catalase.

Localization and density of Porphyromonas gingivalis and Tannerella forsythia in gingival and subgingival granulation tissues affected by chronic or aggressive periodontitis.

Porphyromonas gingivalis and Tannerella forsythia have been thought to be associated with periodontitis; however comprehensive histopathological localization of bacteria in affected human periodontal tissues is not well documented. In the present study, we examined formalin-fixed paraffin-embedded gingival and subgingival granulation tissues from 71 patients with chronic periodontitis and 11 patients with aggressive periodontitis, using immunohistochemistry with novel monoclonal antibodies specific to P. gingivalis or T. forsythia, together with quantitative real-time polymerase chain reaction for each bacterial DNA. Immunohistochemisty revealed both bacterial species extracellularly, as aggregates or within bacterial plaque, and intracellularly in stromal inflammatory cells, squamous epithelium, and capillary endothelium of granulation tissue. Combined analysis with the results from polymerase chain reaction suggested that localization and density of T. forsythia is closely associated with those of P. gingivalis, and that bacterial density is a factor responsible for the cell-invasiveness and tissue-invasiveness of these periodontal bacteria. Detection of these bacteria in the capillary endothelium in some samples suggested possible bacterial translocation into the systemic circulation from inflamed gingival and subgingival granulation tissues. Immunohistochemistry with the novel antibodies showed high specificity and sensitivity, and can be used to locate these periodontal bacteria in routinely-used formalin-fixed paraffin-embedded human tissue sections from systemic locations.