Acellular Extrinsic Fiber Cementum Is Invariably Present in the Superficial Layer of Apical Cementum in Mouse Molar.

The cementum is a highly mineralized tissue that covers the tooth root. The regional differences among the types of cementum, especially in the extrinsic fibers that contribute to tooth support, remain controversial. Therefore, this study used second harmonic generation imaging in conjunction with automated collagen extraction and image analysis algorithms to facilitate the quantitative examination of the fiber characteristics and the changes occurring in these fibers over time. Acellular extrinsic fiber cementum (AEFC) was invariably observed in the superficial layer of the apical cementum in mouse molars, indicating that this region of the cementum plays a crucial role in supporting the tooth. The apical AEFC exhibited continuity and fiber characteristics comparable with the cervical AEFC, suggesting a common cellular origin for their formation. The cellular intrinsic fiber cementum present in the inner layer of the apical cementum showed consistent growth in the apical direction without layering. This study highlights the dynamic nature of the cementum in mouse molars and underscores the requirement for re-examining its structure and roles. The findings of the present study elucidate the morphophysiological features of cementum and have broader implications for the maintenance of periodontal tissue health.

Multiomics analysis of cultured mouse periodontal ligament cell-derived extracellular matrix.

A comprehensive understanding of the extracellular matrix (ECM) is essential for developing biomimetic ECM scaffolds for tissue regeneration. As the periodontal ligament cell (PDLC)-derived ECM has shown potential for periodontal tissue regeneration, it is vital to gain a deeper understanding of its comprehensive profile. Although the PDLC-derived ECM exhibits extracellular environment similar to that of periodontal ligament (PDL) tissue, details of its molecular composition are lacking. Thus, using a multiomics approach, we systematically analyzed cultured mouse PDLC-derived ECM and compared it to mouse PDL tissue as a reference. Proteomic analysis revealed that, compared to PDL tissue, the cultured PDLC-derived ECM had a lower proportion of fibrillar collagens with increased levels of glycoprotein, corresponding to an immature ECM status. The gene expression signature was maintained in cultured PDLCs and was similar to that in cells from PDL tissues, with additional characteristics representative of naturally occurring progenitor cells. A combination of proteomic and transcriptomic analyses revealed that the cultured mouse PDLC-derived ECM has multiple advantages in tissue regeneration, providing an extracellular environment that closely mimics the environment in the native PDL tissue. These findings provide valuable insights for understanding PDLC-derived ECM and should contribute to the development of biomimetic ECM scaffolds for reliable periodontal tissue regeneration.

Effect of Sparc knockout on the extracellular matrix of mouse periodontal ligament cells.

The periodontal ligament (PDL) is a critical component in maintaining tooth stability. It is composed of cells and an extracellular matrix (ECM), each with unique roles in tissue function and homeostasis. Secreted protein acidic and rich in cysteine (SPARC), a calcium-binding matricellular glycoprotein, plays a crucial role in regulating ECM assembly and turnover, alongside facilitating cellular-ECM interactions. In the present study, mass spectrometry-based proteomics was used to assess the impacts of Sparc-knockout (KO) on PDL-derived cells. Results demonstrated that Sparc-KO significantly reduces ECM production and alters its composition with increased levels of type I collagen. Despite this increase in Sparc-KO, type I collagen was not likely to be effectively integrated into the fibrils due to collagen cross-linking impairment. Furthermore, the pathway and process enrichment analyses suggested that SPARC plays a protective role against ECM degradation by antagonistically interacting with cell-surface collagen receptors. These findings provide detailed insights into the multifaceted role of SPARC in ECM organization, including its impact on ECM production, collagen regulation, and interactions with various cellular compartments. A better understanding of these complex mechanisms is crucial for comprehending the causes of periodontal disease and tissue regeneration, where precise control of ECM organization is necessary.

Reverse Remodeling and Non-Contrast T1 Hypointense Infarct Core in Patients With Reperfused Acute Myocardial Infarction.

BACKGROUND: Non-contrast T1 hypointense infarct cores (ICs) within infarcted myocardium detected using cardiac magnetic resonance imaging (CMR) T1 mapping may help assess the severity of left ventricular (LV) injury. However, because the relationship of ICs with chronic LV reverse remodeling (LVRR) is unknown, this study aimed to clarify it.Methods and Results: We enrolled patients with reperfused AMI who underwent baseline CMR on day-7 post-primary percutaneous coronary intervention (n=109) and 12-month follow-up CMR (n=94). Correlations between ICs and chronic LVRR (end-systolic volume decrease ≥15% at 12-month follow-up from baseline CMR) were investigated. We detected 52 (47.7%) ICs on baseline CMR by non-contrast-T1 mapping. LVRR was found in 52.1% of patients with reperfused AMI at 12-month follow-up. Patients with ICs demonstrated higher peak creatine kinase levels, higher B-type natriuretic peptide levels at discharge, lower LV ejection fraction at discharge, and lower incidence of LVRR than those without ICs (26.5% vs. 73.3%, P<0.001) at follow-up. Multivariate logistic regression analysis showed that the presence of ICs was an independent and the strongest negative predictor for LVRR at 12-month follow-up (hazard ratio: 0.087, 95% confidence interval: 0.017-0.459, P=0.004). Peak creatine kinase levels, native T1 values at myocardial edema, and myocardial salvaged indices also correlated with ICs. CONCLUSIONS: ICs detected by non-contrast-T1 mapping with 3.0-T CMR were an independent negative predictor of LVRR in patients with reperfused AMI.

Functional assessment of intermediate coronary artery stenosis with 4-Fr catheters.

The 4-Fr catheter system is not recommended for invasive functional assessment of coronary artery stenosis, because it tends to distort the aortic waveform. This study aimed to identify the incidence of aortic waveform distortion and a feasible method for correct diagnosis of coronary artery stenosis with a 4-Fr catheter. We retrospectively investigated 178 lesions with intermediate coronary artery stenosis. Non-hyperemic distal coronary artery pressure (Pd) and aortic pressure (Pa) were measured with a 4-Fr diagnostic or 6-Fr guiding catheter before and after saline flush. The mean Pd/mean Pa (Pd/Pa) and instantaneous wave-free ratio (iFR) were calculated before and after flushing. We compared the effect of flushing on the changes in Pd/Pa and iFR between the 4-Fr diagnostic and 6-Fr guiding catheters. Using the 4-Fr diagnostic catheter, there was a significant decrease in incidence of aortic waveform distortion from 42.0% (47 lesions) before flushing to 1.8% (2 lesions) after flushing (p < 0.001); the incidence was only 3.0% before saline flush and decreased to 0% after saline flush when using the 6-Fr guiding catheter. The presence of aortic waveform distortion influenced the iFR when the 4-Fr system was used. Functional measurements with the 4-Fr diagnostic catheter require adequate saline flush to remove the influence of aortic waveform distortion.

Novel application of black-blood echo-planar imaging to the assessment of myocardial infarction.

The purpose of this study was to clarify the characteristics of black-blood echo-planar imaging (BB-EPI) in the assessment of infarct-related myocardial edema (IRME), compared with T2-weighted imaging (T2WI). Thirteen acute myocardial infarction (MI) patients after reperfusion and 11 old MI patients underwent BB-EPI and T2WI, excluding those with posterior MI. In acute MI patients, signal intensity ratio (SI ratio) of edema to normal myocardium was measured. Black-blood echo-planar imaging revealed hyperintensity in the same region identified as IRME on T2WI in all acute MI patients, and SI ratio was significantly higher in BB-EPI (2.66 +/- 1.58) than in T2WI (1.44 +/- 0.22) (P < 0.05). However, BB-EPI showed hyperintensity in posterior wall, where there is no clinical evidence of acute MI, in 2 out of 13 acute MI patients. Both T2WI and BB-EPI detected no IRME in known old infarct area of all old MI patients, but BB-EPI showed hyperintensity in the posterior wall of 4 out of 11 old MI patients. Black-blood echo-planar imaging can depict IRME with sufficient suppression of background and blood flow signals, and with excellent edema-to-normal myocardium contrast resolution. However, BB-EPI sometimes shows an inconsistent signal area with T2WI specifically in posterior wall. The wide practical use of BB-EPI requires the solution to this serious problem.

Reduction of circulating soluble fms-like tyrosine kinase-1 plays a significant role in renal dysfunction-associated aggravation of atherosclerosis.

BACKGROUND: Renal dysfunction is commonly accompanied by a worsening of atherosclerosis; however, the underlying molecular mechanism is not fully understood. We examined the role played by soluble fms-like tyrosine kinase-1 (sFlt-1), an endogenous antagonist of the proatherogenic cytokine placental growth factor (PlGF), in the worsening of atherosclerosis in patients with renal dysfunction and in an animal model of renal failure. METHODS AND RESULTS: In this study, 329 patients who received cardiac catheterization and 76 patients who underwent renal biopsy were enrolled. Both plasma sFlt-1 levels and renal sFlt-1 mRNA expression were positively correlated with estimated glomerular filtration rate (P<0.01). The PlGF/sFlt-1 ratio was negatively correlated with estimated glomerular filtration rate (P<0.01), whereas plasma PlGF levels were not affected by it. The PlGF/sFlt-1 ratio was significantly higher in patients with multivessel coronary artery disease than in patients with single-vessel or no coronary artery disease. The reduction of circulating sFlt-1 and renal sFlt-1 mRNA levels was confirmed in five-sixths (5/6)-nephrectomized apolipoprotein E-deficient mice that developed experimental renal dysfunction. Atherosclerotic plaque area and macrophage infiltration into the plaque were significantly higher in 5/6-nephrectomized apolipoprotein E-deficient mice than in control mice, but replacement therapy with recombinant sFlt-1 significantly reduced both plaque formation and macrophage infiltration. CONCLUSIONS: The present study demonstrates that a reduction in the circulating levels of sFlt-1 is associated with the worsening of atherosclerosis that accompanies renal dysfunction.

Usefulness of soluble Fms-like tyrosine kinase-1 as a biomarker of acute severe heart failure in patients with acute myocardial infarction.

Placental growth factor and vascular endothelial growth factor increase angiogenesis and promote healing after acute myocardial infarction (MI), but the significance of soluble Fms-like tyrosine kinase-1 (sFlt-1), an antagonist of placental growth factor and vascular endothelial growth factor, in the setting of acute MI has not been elucidated. The development of acute heart failure in the immediate period after MI is a dreaded complication, but there are no useful biomarkers that identify patients at risk of acute heart failure. We wished to investigate the clinical significance of circulating sFlt-1 during acute MI. We enrolled 174 patients with acute MI, and arterial blood sampling was performed. Plasma levels of sFlt-1 were measured by enzyme-linked immunosorbent assay and their relation to clinical parameters was analyzed. Circulating levels of sFlt-1 on admission were significantly increased in patients with acute MI compared to controls (528.1 +/- 290.9 vs 355.7 +/- 205.0 pg/ml, p <0.001). Circulating levels of sFlt-1 on admission were significantly higher in patients who developed severe acute heart failure requiring mechanical circulatory support devices compared to those with stable hemodynamics (611.4 +/- 373.6 vs 494.6 +/- 243.9 pg/ml, p = 0.016). Moreover, circulating levels of sFlt-1 on admission were directly related to duration of hospitalization. Multivariate logistic analysis showed that hemodynamic instability was predicted by sFlt-1 on admission and left ventricular systolic pressure. In conclusion, the circulating level of sFlt-1 is increased in patients with acute MI, and the sFlt-1 level on admission is a promising biomarker for the development of severe acute heart failure after MI.

Treatment with recombinant placental growth factor (PlGF) enhances both angiogenesis and arteriogenesis and improves survival after myocardial infarction.

BACKGROUND: Placental growth factor (PlGF), a homolog of vascular endothelial growth factor, is reported to stimulate angiogenesis and arteriogenesis in pathological conditions. It was recently demonstrated that PlGF is rapidly produced in myocardial tissue during acute myocardial infarction (MI). However, the effects of exogenous PlGF administration on the healing process after MI are not fully understood. The purpose of the present study was to examine whether PlGF treatment has therapeutic potential in MI. METHODS AND RESULTS: Recombinant human PlGF (rhPlGF: 10 microg) was administered continuously for 3 days in a mouse model of acute MI. rhPlGF treatment significantly improved survival rate after MI and preserved cardiac function relative to control mice. The numbers of CD31-positive cells and alpha-smooth muscle actin-positive vessels in the infarct area were significantly increased in the rhPlGF group. Endothelial progenitor cells (Flk-1(+)Sca-1(+) cells) were mobilized by rhPlGF into the peripheral circulation. Furthermore, rhPlGF promoted the recruitment of GFP-labeled bone marrow cells to the infarct area, but only a few of those migrating cells differentiated into endothelial cells. CONCLUSIONS: Exogenous PlGF plays an important role in healing processes by improving cardiac function and stimulating angiogenesis following MI. It can be considered as a new therapeutic molecule.

Acute myocardial infarction as a systemic prothrombotic condition evidenced by increased von Willebrand factor protein over ADAMTS13 activity in coronary and systemic circulation.

The aim of the present study is to clarify the roles of circulating ADAMTS13 and von Willebrand factor (VWF) in the formation of coronary artery thrombi in acute myocardial infarction (AMI). Twenty-six AMI patients, 37 age-matched healthy controls, and 20 young controls were studied. Plasma ADAMTS13 activity and levels of VWF antigen (VWF: Ag) and unusually large VWF multimer (UL-VWFM) were measured in the femoral vein (FV), aortic root (Ao), and coronary sinus (Cs) immediately before percutaneous coronary intervention (PCI) during the acute phase of AMI, as well as 6 months later. During the acute phase of AMI, plasma levels of VWF: Ag were similar in FV, Ao, and Cs, and were higher than those of age-matched control. In contrast, ADAMTS13 activity in three sampling points in AMI patients was similar to that of age-matched controls. Thus, the ratio of VWF: Ag to ADAMTS13 activity in the acute phase of AMI was significantly higher in all three sampled sites than that of age-matched controls. In the chronic phase, plasma levels of VWF: Ag, ADAMTS13 activity, and the ratio of VWF: Ag to ADAMTS13 activity were similar to those of age-matched controls. UL-VWFM was detected in the acute phase of AMI but not in the chronic phase. The present study showed that the plasma VWF: Ag levels are increased and ADAMTS13 activity is relatively decreased in both systemic and coronary circulation during the acute phase of AMI, suggesting that an imbalance between the enzyme and its substrate may play a role in the formation of occlusive thrombi in a coronary artery.

Blocking T-type Ca2+ channels with efonidipine decreased plasma aldosterone concentration in healthy volunteers.

Efonidipine can block both L- and T- type Ca2+ channels. In a previous in vitro study, we clarified that efonidipine dramatically suppresses aldosterone secretion from human adrenocortical tumor cells during angiotensin II (Ang II)- and K+-stimulation, whereas nifedipine, a dominant L-type Ca2+ channel antagonist, does not. This study was conducted to assess the in vivo effects of efonidipine and nilvadipine on the plasma aldosterone concentration. Placebo, 40 mg of efonidipine, or 2 mg of nilvadipine was administered to five healthy male volunteers. Hemodynamic parameters (pulse rate [PR] and blood pressure [BP]), plasma concentrations of neurohormonal factors (plasma renin activity, Ang II, aldosterone, and adrenocorticotropic hormone [ACTH]), and serum concentrations of Na+ and K+ were measured before and 6 h after administration of the agents. All three agents had little effect on PR and BP. Efonidipine and nilvadipine significantly increased plasma renin activity and Ang II. Both had little effect on ACTH, Na+, and K+. The plasma aldosterone concentration was significantly decreased after efonidipine treatment (88.3 +/- 21.3 to 81.6 +/- 24.9 pg/ml, p = 0.0407), whereas it was significantly increased after nilvadipine treatment (66.5 +/- 12.2 to 82.17 +/- 16.6 pg/ml, p = 0.0049). Placebo had little effect on neurohormonal factors. Efonidipine decreased plasma aldosterone concentration despite the increase in plasma renin activity and Ang II, suggesting that T-type Ca2+ channels may also play an essential role in the secretion of aldosterone in healthy human volunteers.

Usefulness of 16-slice multislice spiral computed tomography for follow-up study of coronary stent implantation.

BACKGROUND: Although multislice spiral computed tomography (MSCT) is a promising technique for non-invasive coronary angiography, its usefulness in patients with stent implantation remains unclear. The aim of the present study was to compare the usefulness of MSCT with that of invasive coronary angiography for evaluating coronary stent patency. METHODS AND RESULTS: Thirty-one patients were enrolled after coronary stent implantation. Sixteen-slice MSCT scans were performed (39.0+/-21.8 days) before follow-up coronary angiography. After assigning an image score based on luminal visibility (1= poor, 2= fair, 3= good), factors determing image quality were analyzed. Among 42 implanted stents, 33 (78%) were assigned an image score of 3, 2 (5%) a score of 2, and 7 (17%) a score of 1. Image scores among stents with diameters >or=3.5 mm were significantly (p<0.05) higher than among smaller stents (

Cardiac expression of placental growth factor predicts the improvement of chronic phase left ventricular function in patients with acute myocardial infarction.

OBJECTIVES: Our aim was to investigate cardiac expression of placental growth factor (PlGF) and its clinical significance in patients with acute myocardial infarction (AMI). BACKGROUND: Placental growth factor is known to stimulate wound healing by activating mononuclear cells and inducing angiogenesis. The clinical significance of PlGF in AMI is not yet known. METHODS: Fifty-five AMI patients and 43 control subjects participated in the study. Peripheral blood sampling was performed on days 1, 3, and 7 after AMI. Blood was also sampled from the coronary artery (CAos) and the coronary sinus (CS), before and after acute coronary recanalization. Cardiac expression of PlGF was analyzed in a mouse AMI model. RESULTS: In AMI patients, peripheral plasma PlGF levels on day 3 were significantly higher than in control subjects. Plasma PlGF levels just after recanalization were significantly higher in the CS than the CAos, which indicates cardiac production and release of PlGF. Peripheral plasma levels of PlGF on day 3 were negatively correlated with the acute phase left ventricular ejection fraction (LVEF), positively correlated with both acute phase peak peripheral monocyte counts and chronic phase changes in LVEF. Placental growth factor messenger ribonucleic acid expression was 26.6-fold greater in a mouse AMI model than in sham-operated mice, and PlGF was expressed mainly in endothelial cells within the infarct region. CONCLUSIONS: Placental growth factor is rapidly produced in infarct myocardium, especially by endothelial cells during the acute phase of myocardial infarction. Placental growth factor might be over-expressed to compensate the acute ischemic damage, and appears to then act to improve LVEF during the chronic phase.