Long-Term Outcomes of Cementless Bipolar Hemiarthroplasty in Young Patients With Osteonecrosis of the Femoral Head: The Impact of Implant Improvements and Preoperative Stage.

Introduction Advancements in bipolar hemiarthroplasty (BHA) implants in the mid-1990s contributed to favorable short-term outcomes for osteonecrosis of the femoral head (ONFH), particularly in cases without acetabular cartilage lesions. Nevertheless, long-term results remain unclear. In this study, we investigated (i) the impact of new-generation BHA implants and (ii) the effect of the preoperative stage on long-term outcomes in young patients with ONFH. Methods The records of consecutive patients with ONFH who underwent cementless BHA were retrospectively reviewed. Patients aged ≥60 years, with <10 years of follow-up, or who underwent acetabular reaming during surgery were excluded. Radiographical and clinical outcomes of patients who received first-generation BHAs and new-generation BHAs (developed after 1998) were compared by stratifying based on preoperative stage 2/3A and 3B/4, according to the Japanese Investigation Committee classification. Results Overall, 50 hips from 39 patients (mean age: 44.6 years; 64% male) with an average follow-up of 18.6 years were included. The frequency of advanced-stage patients was significantly higher in the first-generation BHA group than in the new-generation group. Regarding postoperative outcomes, the first-generation BHA group had higher acetabular erosion grades (p<0.001) and more femoral component loosening than those in the new-generation group (p<0.001). Revisions were performed in eight hips (seven in the first-generation and one in the new-generation BHA groups, p<0.001). In the new-generation BHA group, there were no significant differences in patient background between stage 2/3A and 3B/4 groups, and only one case in the stage 3B/4 group required revision. In the new-generation group, the grade of acetabular erosion was significantly higher for stage 3B/4 than stage 2/3A (p<0.001); other radiographical and clinical outcomes did not differ significantly between stages. Conclusion New-generation BHAs have significantly better implant survival rates for early-stage ONFH than those of first-generation BHAs. These findings indicate that BHA is an acceptable treatment option for early-stage ONFH in young patients.

Thoracic endovascular aortic repair for acute aortic dissection complicated by mesenteric malperfusion: an evaluation by computational fluid dynamics.

Computational fluid dynamics was performed to simulate haemodynamics of type B aortic dissection complicated by mesenteric malperfusion caused by dynamic obstruction in a 70-year-old man. Streamline analysis showed disappearance of antegrade flow in the false lumen of the descending aorta and attenuation of intermittent flap-induced disruption of visceral vessel perfusion after entry coverage. Quantitative analysis showed endovascular repair increased perfusion volume of the coeliac artery and superior mesenteric artery by 55.6% and 77.4%, respectively. Entry closure with thoracic endovascular prosthesis improved mesenteric malperfusion by attenuating the intermittent flap-induced perfusion disruption.

Association between Hospital-acquired Disability and Clinical Outcomes in Older Patients Who Underwent Cardiac Surgical.

OBJECTIVE: This study aimed to clarify the association between hospital-acquired disability (HAD) and prognosis in older patients who underwent cardiac surgery. METHODS: This single-center, retrospective, observational study included 141 patients aged ≥65 years who underwent cardiac surgery at our hospital from November 2016 to August 2021. The primary endpoint of this study was the occurrence of major adverse cardiac and cerebrovascular events (MACCEs) within 2 years of hospital discharge. HAD was defined as a score of ≤5 on any one of the functional independence measure (FIM) subitems at discharge compared to preoperatively. RESULTS: MACCE was observed in 16.3%, and the incidence of MACCE was significantly higher in the HAD group than that in the non-HAD group (12.1 vs. 34.5%, log-rank, p = 0.003). HAD was also significantly associated with the MACCE (hazard ratio [HD]: 2.575, 95% confidence interval [CI]: 1.001-9.655, p = 0.046). The incidence rate of HAD was 20.6%, with age (odds ratio [OR]: 1.260, 95% CI: 1.080-1.470, p = 0.004), preoperative short physical performance battery (SPPB) score (OR: 0.462, 95% CI: 0.301-0.708, p <0.001), and postoperative delirium (OR: 6.660, 95% CI: 1.480-30.000, p = 0.014) identified as significant factors. CONCLUSION: HAD is an independent predictor of MACCE in older patients who underwent cardiac surgery.

Histamine deficiency inhibits lymphocyte infiltration in the submandibular gland of aged mice via increased anti-aging factor Klotho.

OBJECTIVES: Histidine decarboxylase (HDC), a histamine synthase, is expressed in various tissues and is induced by proinflammatory cytokines such as TNFα. As they age, C57BL/6 mice show auto-antibody deposition and lymphocyte infiltration into various tissues, including salivary glands. However, the mechanism underlying cell infiltration and the change in HDC expression in salivary glands with aging remain unclear. Thus, we aimed to elucidate the relationship between histamine and inflammaging. METHODS: We investigated the change in histology and HDC expression in the major salivary glands (parotid, submandibular, and sublingual) of 6-week- and 9-month-old wild-type mice. We also determined the histological changes, cytokine expression, and anti-aging factor Klotho in the salivary glands of 9-month-old wild-type and HDC-deficient (HDC-KO) mice. RESULTS: Cell infiltration was observed in the submandibular gland of 9-month-old wild-type mice. Although most cells infiltrating the submandibular glands were CD3-positive and B220-positive lymphocytes, CD11c-positive and F4/80-positive monocyte lineages were also detected. HDC, TNFα, and IL-1ß mRNA expression increased in the submandibular gland of 9-month-old wild-type mice. The expression of PPARγ, an anti-inflammatory protein, declined in 9-month-old wild-type mice, and Klotho expression increased in 9-month-old HDC-KO mice. Immunohistochemistry showed that Klotho-positive cells disappeared in the submandibular gland of 9-month-old wild-type mice, while Klotho was detected in all salivary glands in HDC-KO mice of the same age. CONCLUSION: Our findings demonstrate the multifunctionality of histamine and can aid in the development of novel therapeutic methods for inflammatory diseases such as Sjogren's syndrome and age-related dysfunctions.

Impact of obstructive ventilatory impairment on intraoperative bleeding during laparoscopic hepatectomy.

PURPOSE: An animal model of laparoscopic hepatectomy showed that bleeding from the hepatic vein is influenced by airway pressure. However, there are little research reports on how airway pressure leads to risks in clinical practice. The main objective of this study was to investigate the impact of preoperative forced expiratory volume % in 1 s (FEV1.0%) on intraoperative blood loss in laparoscopic hepatectomy. METHODS: All patients who underwent pure laparoscopic or open hepatectomy from April 2011 to July 2020 were classified into two groups by preoperative spirometry: those with obstructive ventilatory impairment (obstructive group; FEV1.0% < 70%) and those with normal respiratory function (ormal group; FEV1.0% ≥ 70%). Massive blood loss was defined as 400 mL for laparoscopic hepatectomy. RESULTS: In total, 247 and 445 patients underwent pure laparoscopic and open hepatectomy, respectively. Regarding laparoscopic hepatectomy group, blood loss was significantly greater in the obstructive group (122 vs. 100 mL, P = 0.042). Multivariate analysis revealed that high IWATE criteria which classify the surgical difficulty of laparoscopic hepatectomy (≥ 7, odds ratio (OR): 4.50, P = 0.004) and low preoperative FEV1.0% (< 70%, OR: 2.28, P = 0.043) were independent risk factors for blood loss during laparoscopic hepatectomy. In contrast, FEV1.0% did not affect the blood loss (522 vs. 605 mL, P = 0.113) during open hepatectomy. CONCLUSION: Obstructive ventilatory impairment (low FEV1.0%) may affect the amount of bleeding during laparoscopic hepatectomy.

Molecular genetic positioning of small intestine and papilla of Vater carcinomas including clinicopathological classification.

BACKGROUND: Small intestine carcinoma (SIC) cases in Japan have recently been treated with chemotherapy according to colorectal carcinoma classification, while papilla of Vater carcinoma (PVC) cases according to cholangiocarcinoma (CHC) classification. However, few research reports support the molecular genetic validity of these therapeutic choices. PATIENTS AND METHODS: Here, we investigated the clinicopathological and molecular genetic factors of SIC and PVC. We used the data from the Japanese version of The Cancer Genome Atlas. Additionally, molecular genetic data on gastric adenocarcinoma (GAD), colorectal adenocarcinoma (CRAD), pancreatic ductal adenocarcinoma (PDAC), and CHC were also referred to. RESULTS: This study consisted of tumor samples from 12 patients of SIC and three patients of PVC treated from January 2014 to March 2019. Among them, six patients had pancreatic invasion. t-Distributed stochastic neighbor embedding analysis showed that the gene expression pattern of SIC was similar not only to those of GAD and CRAD, but also to that of PDAC in the pancreatic invasion patients. In addition, PVC resembled the GAD, CRAD, and PDAC, rather than the CHC. The molecular genetic characteristics of the six patients with pancreatic invasion were: one had high microsatellite instability, two had a TP53 driver mutation, and three had tumor mutation burden values <1 mutation/Mb with no driver mutation. CONCLUSIONS: In this study, the extensive gene expression profiling of organ carcinomas newly suggests that SIC or PVC may resemble GAD, CRAD, and PDAC. In addition, the data demonstrate that pancreatic invasive patients may be classified into several subtypes using molecular genetic factors.

A maternal high-fat diet induces fetal origins of NASH-HCC in mice.

Maternal overnutrition affects offspring susceptibility to nonalcoholic steatohepatitis (NASH). Male offspring from high-fat diet (HFD)-fed dams developed a severe form of NASH, leading to highly vascular tumor formation. The cancer/testis antigen HORMA domain containing protein 1 (HORMAD1), one of 146 upregulated differentially expressed genes in fetal livers from HFD-fed dams, was overexpressed with hypoxia-inducible factor 1 alpha (HIF-1alpha) in hepatoblasts and in NASH-based hepatocellular carcinoma (HCC) in offspring from HFD-fed dams at 15 weeks old. Hypoxia substantially increased Hormad1 expression in primary mouse hepatocytes. Despite the presence of three putative hypoxia response elements within the mouse Hormad1 gene, the Hif-1alpha siRNA only slightly decreased hypoxia-induced Hormad1 mRNA expression. In contrast, N-acetylcysteine, but not rotenone, inhibited hypoxia-induced Hormad1 expression, indicating its dependency on nonmitochondrial reactive oxygen species production. Synchrotron-based phase-contrast micro-CT of the fetuses from HFD-fed dams showed significant enlargement of the liver accompanied by a consistent size of the umbilical vein, which may cause hypoxia in the fetal liver. Based on these findings, a maternal HFD induces fetal origins of NASH/HCC via hypoxia, and HORMAD1 is a potential therapeutic target for NASH/HCC.

Polarized light retardation analysis allows for the evaluation of tension in individual stress fibers.

The tension in the stress fibers (SFs) of cells plays a pivotal role in determining biological processes such as cell migration, morphological formation, and protein synthesis. Our previous research developed a method to evaluate the cellular contraction force generated in SFs based on photoelasticity-associated retardation of polarized light; however, we employed live cells, which could have caused an increase in retardation and not contraction force. Therefore, the present study aimed to confirm that polarized light retardation increases inherently due to contraction, regardless of cell activity. We also explored the reason why retardation increased with SF contractions. We used SFs physically isolated from vascular smooth muscle cells to stop cell activity. The retardation of SFs was measured after ATP administration, responsible for contracting SFs. The SFs were imaged under optical and electron microscopes to measure SF length, width, and retardation. The retardation of isolated SFs after ATP administration was significantly higher than before. Thus, we confirmed that retardation increased with elevated tension in individual SFs. Furthermore, the SF diameter decreased while the SF length remained almost constant. Thus, we conclude that a contraction force-driven increase in the density of SFs is the main factor for the rise in polarized light retardation.

False lumen/true lumen wall pressure ratio is increased in acute non-A non-B aortic dissection.

OBJECTIVES: We aimed to determine whether non-A non-B aortic dissection (AD) differs in morphologic and haemodynamic properties from type B AD. METHODS: We simulated and compared haemodynamics of patients with acute type B or acute non-A non-B AD by means of computational fluid dynamics. Wall pressure and wall shear stress (WSS) in both the true lumen (TL) and false lumen (FL) at early, mid- and late systole were evaluated. Morphology, WSS and the FL/TL wall pressure ratio were compared between groups. RESULTS: Nineteen patients (type B, n = 7; non-A non-B, n = 12) were included. The median age (51 [46, 67] vs 53 [50, 63] years; P = 0.71) and a complicated course (14% vs 33%; P = 0.6) did not differ between the type B group and the non-A non-B group. However, the median entry tear width was increased in the non-A non-B group (9.7 [7.3, 12.7] vs 16.3 [11.9, 24.9] mm; P = 0.010). Streamlines showed, in patients with non-A non-B AD, blood from the TL flowed into the FL via the entry tear. Prevalence of a FL/TL wall pressure ratio >1.0 (type B versus non-A non-B) at early, mid- and late systole was 57% vs 83% (P = 0.31), 43% vs 83% (P = 0.13) and 57% vs 75% (P = 0.62), respectively. WSS did not differ between the groups. CONCLUSIONS: The increased FL/TL wall pressure ratio observed during systole in non-A non-B AD may beget a complicated presentation.

Durability of Bioprosthetic Valves in Patients on Dialysis.

PURPOSE: This study focused on clarifying the durability of bioprosthetic valves in current practice. METHODS: A total of 238 consecutive patients who underwent aortic valve replacement at a single institution from 2011 to 2020 were reviewed. We evaluated valve-related outcomes such as structural valve deterioration (SVD), especially in dialysis patients who received bioprosthetic valve. RESULTS: Among the tissue valves implanted in 212 patients, 5 SVDs were recorded and 3 valves were replaced. All early valve failures occurred in relatively young dialysis patients and were recorded 3 to 5 years after the initial operation. Freedom from SVD at 6 years was 49.9% in patients on dialysis, compared with 100% in non-dialysis patients. Predictors of better survival in dialysis patients were better preoperative functional class and larger prosthetic valve size. CONCLUSIONS: The durability of bioprosthetic valves in the aortic position was suboptimal in dialysis patients. Mechanical valves can be an option for young, healthy dialysis patients with a large aortic valve annulus.

Blood flow stagnation after treatment of a giant internal carotid artery aneurysm: a computed fluid dynamics analysis.

Balloon test occlusion (BTO) is an angiographic test to evaluate ischemic tolerance after permanent occlusion of an internal carotid artery (ICA). BTO can simulate ischemia caused by parent artery occlusion and can be used to select a suitable bypass surgery using specific criteria. On the other hand, a postoperative thrombus can form despite proper case selection, optimal radiological evaluation, and an appropriate surgical strategy. Postoperative ischemic complications related to perforating branches are clinically significant. This simulation study aimed to analyze postoperative flow characteristics and elucidate the cause of ischemic complications related to the perforating branch using computational fluid dynamics (CFD). An unexpected postoperative thrombus formation related to the perforating branch occurred after treating a giant aneurysm in the cavernous portion of the ICA in a patient. Three-dimensional digital subtraction angiography was used to acquire flow data and set up the CFD simulation. The flow simulations were performed at various bypass flow rates. The CFD analysis indicated flow stagnation in the ICA only when surgical treatment using a low-flow bypass graft was performed. Thrombus formation may lead to ischemic complications related to the perforating branch, such as the anterior choroidal artery. BTO did not reflect the influence of bypass blood flow. Therefore, recognizing that blood flow stagnation may occur and comprehensively deciding on the surgical strategy by CFD analysis can be helpful to prevent ischemic complications in patients with giant aneurysms.

Bicuspidalization of the Native Tricuspid Aortic Valve: A Porcine in Vivo Model of Bicuspid Aortopathy.

Objective: To examine early histologic changes in the aorta exposed to bicuspid flow. Material and Methods: A porcine bicuspid aortopathy model was developed by suturing aortic cusps. Of nine pigs, eight underwent sham surgery (n=3) or bicuspidalization (n=5); one was used as an intact control. Wall shear stress (WSS) was assessed by computational fluid dynamics (CFD). Animals were exposed to normal or bicuspid flow for 48 h and were then euthanized for histologic examinations. Results: No animal died intraoperatively. One animal subjected to bicuspidalization died of respiratory failure during postoperative imaging studies. Echocardiography showed the aortic valve area decreased from 2.52±1.15 to 1.21±0.48 cm2 after bicuspidalization, CFD revealed increased maximum WSS (10.0±5.2 vs. 54.0±25.7 Pa; P=0.036) and percentage area of increased WSS (>5 Pa) in the ascending aorta (30.3%±24.1% vs. 81.3%±13.4%; P=0.015) after bicuspidalization. Hematoxylin-eosin staining and transmission electron microscopy showed subintimal edema and detached or degenerated endothelial cells following both sham surgery and bicuspidalization, regardless of WSS distribution. Conclusion: A bicuspid aortic valve appears to increase aortic WSS. The endothelial damage observed might have been related to non-pulsatile flow (cardiopulmonary bypass). Chronic experiments are needed to clarify the relationship between hemodynamic stress and development of bicuspid aortopathy.

B16 Melanoma Cancer Cells with Higher Metastatic Potential are More Deformable at a Whole-Cell Level.

INTRODUCTION: Metastasis is a process in which cancer cells spread from the primary focus site to various other organ sites. Many studies have suggested that reduced stiffness would facilitate passing through extracellular matrix when cancer cells instigate a metastatic process. Here we investigated the compressive properties of melanoma cancer cells with different metastatic potentials at the whole-cell level. Differences in their compressive properties were analyzed by examining actin filament structure and actin-related gene expression. METHODS: Compressive tests were carried out for two metastatic B16 melanoma variants (B16-F1 and B16-F10) to characterize global compressive properties of cancer cells. RNA-seq analysis and fluorescence microscopic imaging were performed to clarify contribution of actin filaments to the global compressive properties. RESULTS: RNA-seq analysis and fluorescence microscopic imaging revealed the undeveloped structure of actin filaments in B16-F10 cells. The Young's modulus of B16-F10 cells was significantly lower than that of B16-F1 cells. Disruption of the actin filaments in B16-F1 cells reduced the Young's modulus to the same level as that of B16-F10 cells, while the Young's modulus in B16-F10 cells remained the same regardless of the disruption. CONCLUSIONS: In B16 melanoma cancer cell lines, cells with higher metastatic potential were more deformable at the whole-cell level with undeveloped actin filament structure, even when highly deformed. These results imply that invasive cancer cells may gain the ability to inhibit actin filament development. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s12195-021-00677-w).

Carcinomatous cirrhosis as radiographically occult liver metastases of breast cancer: A systematic literature review.

In the present study, we aimed to clarify features of carcinomatous cirrhosis from breast cancer presenting as refractory transudate ascites and acute liver failure. In our systematic literature review, we identified 26 studies and 31 cases including our case of this rare condition. Our patient was a 49-year-old woman with a history of ascites and liver failure for the past 4 years and currently being treated for invasive ductal breast cancer. On radiography, she had occult liver metastases that were confirmed using laparoscopic liver biopsy. In the 31 cases, data on the reported year, age, type of primary breast cancer, time from breast cancer diagnosis, presence of ascites and/or varices, liver biopsy, diagnostic modalities, outcomes, and survival were documented and analyzed. All cases were reported during 1984-2020, with a mean patient age of 52.9 years. Eighteen patients (58.1%) were diagnosed with ductal breast cancer. Twenty-two patients (70.9%) had ascites. All patients had gradual progression to liver dysfunction. The following tests were performed: computed tomography (77.4%); ultrasound (58.0%); liver biopsy (100%); postmortem biopsy (35.5%), transjugular liver biopsy (32.3%), and laparoscopic liver biopsy (3.2%). Outcomes were reported for 29 patients, of whom 24 (82.3%) died after 1 day to 16 months. Invasive ductal carcinoma was the most common histological type; however, invasive lobular carcinoma was more frequent (32.3%) than its reported incidence in the breast. Carcinomatous cirrhosis has poor prognosis at relatively rash and is difficult to diagnose with usual modalities. It may be associated with E-cadherin loss or CD44 pronouncement.

Fluid dynamics analyses of the intrahepatic portal vein tributaries using 7-T MRI.

BACKGROUND: Assessing portal vein (PV) hemodynamics is an essential part of liver disease management/liver surgery, yet the optimal methods of assessing intrahepatic PV flow have not yet been established. This study investigated the usefulness of 7-Tesla MRI with hemodynamic analysis for detecting small flow changes within narrow intrahepatic PV branches. METHODS: Flow data in the main PV was obtained by two methods, two-dimensional cine phase contrast-MRI (2D cine PC-MRI) and three-dimensional non-cine phase contrast-MRI (3D PC-MRI). Hemodynamic parameters, such as flow volume rate, flow velocity, and wall shear stress in intrahepatic PV branches were calculated before and after a meal challenge using 3D PC-MRI and hemodynamic analysis. RESULTS: The hemodynamic parameters obtained using 3D PC-MRI and 2D cine PC-MRI were similar. All intrahepatic PV branches were clearly depicted in eight planes, and significant changes in flow volume rate were seen in three planes. Average and maximum velocities, cross-sectional area, and wall shear stress were similar between before and after a meal challenge in all planes. CONCLUSION: 7-Tesla 3D PC-MRI combined with hemodynamic analysis is a promising tool for assessing intrahepatic PV flow and enables future studies in small animals to investigate PV hemodynamics associated with liver disease/postoperative liver recovery.

Antiatherosclerotic Phenotype of Perivascular Adipose Tissue Surrounding the Saphenous Vein in Coronary Artery Bypass Grafting.

Background Perivascular adipose tissue (PVAT) is associated with metabolically driven chronic inflammation called metaflammation, which contributes to vascular function and the pathogenesis of vascular disease. The saphenous vein (SV) is commonly used as an essential conduit in coronary artery bypass grafting, but the long-term patency of SV grafts is a crucial issue. The use of the novel "no-touch" technique of SV harvesting together with its surrounding tissue has been reported to result in good long­term graft patency of SV grafts. Herein, we investigated whether PVAT surrounding the SV (SV-PVAT) has distinct phenotypes compared with other PVATs of vessels. Methods and Results Fat pads were sampled from 48 patients (male/female, 32/16; age, 72±8 years) with coronary artery disease who underwent elective coronary artery bypass grafting. Adipocyte size in SV-PVAT was significantly larger than the sizes in PVATs surrounding the internal thoracic artery, coronary artery, and aorta. SV-PVAT and PVAT surrounding the internal thoracic artery had smaller extents of fibrosis, decreased gene expression levels of fibrosis-related markers, and less metaflammation, as indicated by a significantly smaller extent of cluster of differentiation 11c-positive M1 macrophage infiltration, higher gene expression level of adiponectin, and lower gene expression levels of inflammatory cytokines, than did PVATs surrounding the coronary artery and aorta. Expression patterns of adipocyte developmental and pattern-forming genes were totally different among the PVATs of the vessels. Conclusions The phenotype of SV-PVAT, which may result from inherent differences in adipocytes, is closer to that of PVAT surrounding the internal thoracic artery than that of PVAT surrounding the coronary artery or that of PVAT surrounding the aorta. SV-PVAT has less metaflammation and consecutive adipose tissue remodeling, which may contribute to high long-term patency of grafting when the no-touch technique of SV harvesting is used.

Effect of ovariectomy induced osteoporosis on metaphysis and diaphysis repair process.

The fracture repair process is known to be delayed in postmenopausal women, under estrogen-deficient status. Osteoporotic fracture mainly occurs in the metaphyseal region of the long bone; however, most studies on fracture healing have focused on the diaphyseal region. In this study, we compared the repair process between metaphysis and diaphysis of ovariectomized (OVX) and Sham mice, and analyzed the effects of short-term estrogen administration in OVX mice. Mice were divided into four experimental groups, including Sham, OVX, OVX + vehicle, and OVX + 17ß-estradiol (E2). Bone apertures were formed in the tibial metaphysis and diaphysis. The samples were collected and examined by micro-computed tomography, and using histological, histochemical, and immunohistochemical analysis at different time points after the surgery. The cartilaginous callus was formed at the diaphysis site of both the groups, which was sequentially replaced by bone on the periosteum side. Medullary callus was formed in all the groups; however, the volume of the callus in OVX mice was significantly lesser (˜30%) than that in Sham mice. Furthermore, in the metaphysis, no differences were observed in the medullary callus and bone mineral density between the two groups from day 21 to 28. The diaphysis of OVX group was not completely repaired even by day 28. In both the sites of OVX mice, ALP activity and disappearance of Gr-1 positive cells were delayed compared to that of Sham. Estrogen administration improved medullary callus formation in the diaphysis, however not in the metaphysis. The effect of ovariectomy on the repair process in diaphysis was greater than that in metaphysis. Our findings clarify the differences between the metaphysis and diaphysis repair process using OVX mouse model and suggest that the estrogen sensitivities differ between the sites during the bone repair process.

Role of Innate Inflammation in the Regulation of Tissue Remodeling during Tooth Eruption.

Tooth eruption is characterized by a coordinated complex cascade of cellular and molecular events that promote tooth movement through the eruptive pathway. During tooth eruption, the stratum intermedium structurally changes to the papillary layer with tooth organ development. We previously reported intercellular adhesion molecule-1 (ICAM-1) expression on the papillary layer, which is the origin of the ICAM-1-positive junctional epithelium. ICAM-1 expression is induced by proinflammatory cytokines, including interleukin-1 and tumor necrosis factor. Inflammatory reactions induce tissue degradation. Therefore, this study aimed to examine whether inflammatory reactions are involved in tooth eruption. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed sequential expression of hypoxia-induced factor-1α, interleukin-1ß, and chemotactic factors, including keratinocyte-derived chemokine (KC) and macrophage inflammatory protein-2 (MIP-2), during tooth eruption. Consistent with the RT-PCR results, immunohistochemical analysis revealed KC and MIP-2 expression in the papillary layer cells of the enamel organ from the ameloblast maturation stage. Moreover, there was massive macrophage and neutrophil infiltration in the connective tissue between the tooth organ and oral epithelium during tooth eruption. These findings suggest that inflammatory reactions might be involved in the degradation of tissue overlying the tooth organ. Further, these reactions might be induced by hypoxia in the tissue overlying the tooth organ, which results from decreased capillaries in the tissue. Our findings indicate that bacterial infections are not associated with the eruption process. Therefore, tooth eruption might be regulated by innate inflammatory mechanisms.

Histidine decarboxylase deficiency inhibits NBP-induced extramedullary hematopoiesis by modifying bone marrow and spleen microenvironments.

Histidine decarboxylase (HDC), a histamine synthase, is expressed in various hematopoietic cells and is induced by hematopoietic cytokines such as granulocyte colony-stimulating factor (G-CSF). We previously showed that nitrogen-containing bisphosphonate (NBP)-treatment induces extramedullary hematopoiesis via G-CSF stimulation. However, the function of HDC in NBP-induced medullary and extramedullary hematopoiesis remains unclear. Here, we investigated changes in hematopoiesis in wild-type and HDC-deficient (HDC-KO) mice. NBP treatment did not induce anemia in wild-type or HDC-KO mice, but did produce a gradual increase in serum G-CSF levels in wild-type mice. NBP treatment also enhanced Hdc mRNA expression and erythropoiesis in the spleen and reduced erythropoiesis in bone marrow and the number of vascular adhesion molecule 1 (VCAM-1)-positive macrophages in wild-type mice, as well as increased the levels of hematopoietic progenitor cells and proliferating cells in the spleen and enhanced expression of bone morphogenetic protein 4 (Bmp4), CXC chemokine ligand 12 (Cxcl12), and hypoxia inducible factor 1 (Hif1) in the spleen. However, such changes were not observed in HDC-KO mice. These results suggest that histamine may affect hematopoietic microenvironments of the bone marrow and spleen by changing hematopoiesis-related factors in NBP-induced extramedullary hematopoiesis.

Trabecular structure and composition analysis of human autogenous bone donor sites using micro-computed tomography.

OBJECTIVES: To evaluate the bone microstructure of autogenous graft bone in elderly people (mean age, 66 years), we compared the bone volume/total volume and bone mineral density of four donor sites that are commonly harvested for maxillofacial surgery and dental implant treatments, using X-ray micro-computed tomography. METHODS: Eighteen Japanese cadavers were included in this study. Overall, 66 harvested bones (mandibular symphysis, mandibular ramus, ilium, and tibia) were studied. Micro-computed tomography scans of four sites were performed to analyze the trabecular structures, bone mineral density, and bone volume/total volume in these bones. RESULTS: The mandibular symphysis bones showed the highest bone volume/total volume and bone mineral density at the four sites. There was a significant difference in the bone volume/total volume between the mandibular symphysis and tibia groups. There was also a significant difference in bone mineral density between the mandibular symphysis group and the ilium and tibia groups. In the three-dimensional observations, the structures of the mandibular trabecular were plate-type. The structures of the tibial bone were mixtures of plate- and rod-types. In the ilium, most trabecula were rod-shaped. CONCLUSIONS: Mandibular symphysis and ramus had a higher bone volume/total volume and bone mineral density of the four sites and did not show regressive changes in our findings. Mandibular bone is the most suitable source of autogenous graft bone material because of its superior bone quality and quantity.