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Background: Real-time monitoring of generator impedance drop is not considered in CLOSE protocol pulmonary vein (PV) isolation (PVI) in patients with atrial fibrillation (AF). We verified whether additional information of impedance drop could minimize ablation index required for PVI using modified CLOSE protocol (target ablation index ≥ 500 on anterior wall and ≥400 on posterior wall along with inter-lesion distance of 3-6 mm and maximum power of 35 W) without any adverse effect of procedural data and efficacy., Methods: Sixty consecutive Japanese AF patients [paroxysmal AF: 43 (72 %) patients] underwent first-time PVI with modified CLOSE protocol with real-time monitoring of impedance drop (impedance-guided modified CLOSE protocol). Ablation tags were colored according to impedance drop and ablation was immediately terminated before reaching target ablation index if impedance drop of ≥10 Ω was confirmed. Ablation index needed for PVI, first-pass PVI rate, other procedural data, and atrial tachyarrhythmia recurrence were evaluated., Results: Mean ablation index and impedance drop on anterior and posterior walls were 437.6 ± 43.5 Ω and 10.2 ± 2.6 Ω and 393.3 ± 27.4 Ω and 9.3 ± 2.2 Ω, respectively. First-pass PVI per PV pair was accomplished in 90/120 (75 %). No complications occurred. PV gaps after first-pass ablation were locationally most often found on right posterior wall than on the other parts (p < 0.001). There were no differences in mean contact force, impedance drop, and ablation index between walls with and without PV gaps after first-pass PV ablation. During a mean follow-up of 24 ± 9 months, survival from atrial tachyarrhythmia recurrence was 51/60 (85 %) patients., Conclusions: Using additional generator impedance drop information may be useful to minimize radiofrequency current application to accomplish PVI with modified CLOSE protocol while maintaining efficacy and safety in Japanese AF population., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Idiopathic multicentric Castleman disease (iMCD) is a rare lymphoproliferative disorder, and only a few cases have been reported to be complicated with autoimmune hemolytic anemia (AIHA). A 43-year-old man who presented with multiple swollen lymph nodes was diagnosed with iMCD. He was also diagnosed with AIHA based on laboratory findings, including the results of a bone marrow aspiration study. The patient was treated with tocilizumab; however, the effect was limited, probably due to anti-drug antibodies. Tocilizumab was therefore switched to rituximab, and his anemia was improved. Complication with AIHA should be carefully considered when iMCD patients present with severe anemia.

Stress-induced inflammatory responses in the portal system are characterized by elevations in serum concentrations of interleukin-6 (IL-6) and endotoxins such as lipopolysaccharides (LPS). LPS translocation from the intestinal to the capillary lumen occurs via LPS endocytosis by the capillary endothelium. Because the capillary endothelium of the small intestinal submucosa is fenestrated, we determined the role of pore modifications within the fenestrated endothelium in relaying inflammatory stress responses in the portal vein. We evaluated changes in the diameter and density of endothelial pores of the lamina propria of intestinal villi induced by continuous light (CL) exposure for 48 h and the correlation between these changes and serum IL-6 concentration in the portal vein in a rat model. We found significant increases in both the pore diameter and density, accompanied by a significant increase in portal IL-6 concentration; these changes were significantly attenuated by pretreatment with propranolol, a beta adrenergic receptor antagonist. In contrast, intravenous noradrenaline administration mimicked CL-induced modifications of the diameter and density of pores and the elevation of portal vein IL-6 concentration. These findings suggested that stress-induced inflammatory responses in the portal system may be a part of the modifications of the endothelial pores triggered by sympathetic activation.

Objective: Gout, caused by hyperuricaemia, is a multifactorial disease. Although genome-wide association studies (GWASs) of gout have been reported, they included self-reported gout cases in which clinical information was insufficient. Therefore, the relationship between genetic variation and clinical subtypes of gout remains unclear. Here, we first performed a GWAS of clinically defined gout cases only., Methods: A GWAS was conducted with 945 patients with clinically defined gout and 1213 controls in a Japanese male population, followed by replication study of 1048 clinically defined cases and 1334 controls., Results: Five gout susceptibility loci were identified at the genome-wide significance level (p<5.0×10(-8)), which contained well-known urate transporter genes (ABCG2 and SLC2A9) and additional genes: rs1260326 (p=1.9×10(-12); OR=1.36) of GCKR (a gene for glucose and lipid metabolism), rs2188380 (p=1.6×10(-23); OR=1.75) of MYL2-CUX2 (genes associated with cholesterol and diabetes mellitus) and rs4073582 (p=6.4×10(-9); OR=1.66) of CNIH-2 (a gene for regulation of glutamate signalling). The latter two are identified as novel gout loci. Furthermore, among the identified single-nucleotide polymorphisms (SNPs), we demonstrated that the SNPs of ABCG2 and SLC2A9 were differentially associated with types of gout and clinical parameters underlying specific subtypes (renal underexcretion type and renal overload type). The effect of the risk allele of each SNP on clinical parameters showed significant linear relationships with the ratio of the case-control ORs for two distinct types of gout (r=0.96 [p=4.8×10(-4)] for urate clearance and r=0.96 [p=5.0×10(-4)] for urinary urate excretion)., Conclusions: Our findings provide clues to better understand the pathogenesis of gout and will be useful for development of companion diagnostics., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Gout is a common disease resulting from hyperuricemia which causes acute arthritis. Recently, genome-wide association studies revealed an association between serum uric acid levels and a common variant of leucine-rich repeat-containing 16A (LRRC16A) gene. However, it remains to be clarified whether LRRC16A contributes to the susceptibility to gout. In this study, we investigated the relationship between rs742132 in LRRC16A and gout. A total of 545 Japanese male gout cases and 1,115 male individuals as a control group were genotyped. rs742132 A/A genotype significantly increased the risk of gout, conferring an odds ratio of 1.30 (95 % CI 1.05-1.60; p = 0.015). LRRC16A encodes a protein called capping protein ARP2/3 and myosin-I linker (CARMIL), which serves as an inhibitor of the actin capping protein (CP). CP is an essential element of the actin cytoskeleton, which binds to the barbed end of the actin filament and regulates its polymerization. In the apical membrane of proximal tubular cells in the human kidney, the urate-transporting multimolecular complex (urate transportsome) is proposed to consist of several urate transporters and scaffolding proteins, which interact with the actin cytoskeleton. Thus, if there is a CARMIL dysfunction and regulatory disability in actin polymerization, urate transportsome may be unable to operate appropriately. We have shown for the first time that CARMIL/LRRC16A was associated with gout, which could be due to urate transportsome failure.

The α3(V) chain is poorly characterized among type V collagen chains. Pro-α3(V) collagen is expressed in newly synthesized bone as well as in the superficial fascia of developing muscle. Present study examined the expression in a mouse model of wound healing. Real-time reverse transcriptase polymerase chain reaction and in situ hybridization revealed transient expression of pro-α3(V) chain at a lower level than other fibrillar collagen genes after injury. Immunohistochemistry showed a similar expression pattern in the injured skin. In addition, electron microscopy showed that pro-α3(V) chain was localized in the amorphous nonfibrillar region, but not in fine or dense fibrils. The pro-α3(V) chain co-localized with heparan sulfate, which appeared in the skin after injury and might bind via an acidic segment of the pro-α3(V) chain. The matrix containing the pro-α3(V) chain may therefore be needed for the initiation of wound healing.

Myofibroblast transdifferentiation plays a crucial role in the development and progression of renal tubulointerstitial fibrosis. However, the significance of α-smooth muscle actin (α-SMA) expression, which is the major morphological characteristic of myofibroblasts, remains to be determined in detail. The effect of α-SMA expression on fibrosis tissue was examined by using a fibrosis model (collagen gel) in vitro. The transdifferentiation of fibroblasts into myofibroblasts was triggered in the culture medium with 0.5% fetal bovine serum (FBS)+transforming growth factor (TGF)-β1, but not with 10% FBS+TGF-β1. The TGF-β1-induced gel contraction caused by myofibroblasts was greater than that by fibroblasts. Gel contraction by myofibroblasts involved the Ca²+-dependent myosin light chain kinase pathway, as well as the activation of Rho kinase and p38 mitogen-activated protein kinase (MAPK). Taken together, these findings suggest that α-SMA expression in renal interstitial fibroblasts, i.e., myofibroblast transdifferentiation, accelerates the contraction of the tubulointerstitial fibrosis tissue via the Ca²+-dependent pathway, in addition to the pathways involved in fibroblast contraction; this event may lead to renal atrophy and renal failure.

Extreme replacement of skeletal muscles by adipose tissue was found in an 86-year old Japanese male cadaver during dissection practice for medical students at Oita University School of Medicine. Especially, the bilateral sartorius muscles looked overall like adipose tissue. The man had suffered from diabetes mellitus, renal failure, hypertension and hypothyroidism before his death. He was also an alcohol drinker. He had been bedridden late in life. The cause of death was renal failure. In microscopy, the adipose tissue-like sartorius muscle was shown to consist of leptin-positive adipocytes with a small number of degenerated muscle fibers. Fatty replacement, or fatty degeneration, appears to result from endocrine and metabolic disorders, and being bedridden leads to muscle atrophy and damage, although the origin of the adipocytes which emerged in the degenerated muscles is unknown.

Background: Epiplakin (EPPK) belongs to the plakin family of cytolinker proteins and, resembling other members of the plakin family such as BPAG1 (an autoantigen of bullous pemphigoid) and plectin, EPPK has plakin repeat domains (PRDs) that bind to intermediate filaments. Elimination of EPPK by gene targeting in mice resulted in the acceleration of keratinocyte migration during wound healing. EPPK is expressed in proliferating keratinocytes at wound edges and, in view of its putative function in binding to keratin, we postulated that the keratin network in EPPK-null (EPPK(-/-)) mice might be disrupted during wound healing., Objective: To examine this hypothesis and to determine the precise localization of EPPK in relation to keratin filaments, we compared the non-wounded and wounded epidermis of wild-type and EPPK(-/-) mice., Methods: Non-wounded epidermis and wounded epidermis from wild-type and EPPK(-/-) mice were examined by immunofluorescence staining and electron microscopy before and after double immunostaining., Results: EPPK was colocalized with keratin 17 (K17) more extensively than with other keratins examined in wounded epidermis. The expression of K5, K10, K6, and K17 was the same in EPPK(-/-) mice after wounding as in normal mice, but diameters of keratin filaments were reduced in EPPK(-/-) keratinocytes. Electron microscopy after immunostaining revealed that EPPK colocalized with K5, K10 and K6 after wounding in wild-type mice., Conclusion: Our data indicate that EPPK accelerates keratin bundling in proliferating keratinocytes during wound healing and suggest that EPPK might contribute to reinforcement of keratin networks under mechanical stress., (Copyright © 2010 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Rat ascitic-type hepatoma AH7974 cells express CXCR4 mRNA and protein at high levels and also show vigorous migratory responses to its ligand CXCL12. We have shown that AMD3100 (a specific CXCR4 antagonist) effectively reduced tumor invasion into the milky spot in Sprague-Dawley rats inoculated with AH7974 cells. A histological analysis revealed that the milky spots from AMD3100-treated rats were both smaller and consisted of fewer constituent cells and blood vessels than those from the AH7974 inoculated rats. Alkaline phosphatase staining also showed a statistically significant reduction in the area of the milky spots in the AMD3100-treated rats in comparison to the AH7974 inoculated rats (P < 0.0001). Green fluorescence protein (GFP)-tagged AH7974 cells were constructed to detect the localization of the tumor cells in the milky spots. There were fewer GFP-tagged AH7974 cells in the AMD3100-treated rats than in the AH7974 inoculated rats. The number of eosinophils and mast cells increased in the milky spots of AH7974-inoculated rats, and angiogenesis was also seen. In comparison, both cell proliferation and angiogenesis were inhibited in the milky spots of the AMD3100-treated rats. Collectively, our results strongly suggest that the CXCR4/CXCL12 axis plays an important role in the development of peritoneal carcinomatosis. As such, CXCR4 may be a potential therapeutic target for peritoneal carcinomatosis.

The purpose of this experiment is to examine the proliferative process of rat acinar cells after parotid duct ligation and reopening. Two experimental groups were observed. The first group was killed from 0 to 14 days after the duct ligation. In the second group, the duct was clipped for 14 days, and it was reopened. Following a period of from 2 to 28 days after removal of the clip, the glands were removed to perform a histological analysis, including hematoxylin-eosin (HE), immunofluorescent staining using HAM8 antibody, which recognizes connexin 32, and transmission electron microscopy (TEM). In the experimental gland from the 1st group at 6 days after ligation (I-6D), the acinar cells disappeared. In the tissue from the 2nd group 8 days after reopening (II-8D), newly formed acinar cells were found again. Lobular structure of the parotid glands recovered in the II-21D. HAM8 signals were observed between normal acinar cells, while they declined in the tissue from I-1D, and they were not observed in the I-2D. HAM8 signals were first observed in the II-25D and then subsequently returned to normal levels in the II-28D. These results suggest that the intercellular communication and functional recovery was not complete 25 days after reopening of the duct.In conclusion, the recovery of the acinar structure was recognized during an extended period of duct ligation, however, a time lag between the morphological and functional recovery was found to exist.

Tubulointerstitial fibrosis in diabetic nephropathy (DN) was investigated using an in vitro tissue model of remodeling, to determine the pathogenic mechanism of fibrosis that leads to renal atrophy, i.e., renal failure. The remodeling model consisted of a renal fibroblast-populated collagen lattice (FPCL). The overexpression of transforming growth factor (TGF)-beta1 in the diabetic kidney gave rise to FPCL contraction. FPCL relaxation was induced by the subsequent addition of cytochalasin D. The FPCL failed to contract when exposed to TGF-beta1 plus Y27632, a Rho kinase inhibitor. TGF-beta1 induced the phosphorylation of myosin light chains, and Y27632 blocked this activity. TGF-beta1-induced FPCL contraction was suppressed by the addition of 2,3-butanedione monoxime, a myosin ATPase inhibitor. As shown in the video, the contraction rate of the projections of the cells in the FPCL was significantly greater in the TGF-beta1 group than in the control group. Collectively, these results indicate that TGF-beta1-induced FPCL contraction is attributable to actin-myosin interactions in the fibroblasts through the activation of Rho kinase, the phosphorylation of myosin light chains, and the subsequent activation of myosin ATPase. We propose that via these mechanisms, tubulointerstitial fibrosis generates tissue contraction that leads to renal atrophy and renal failure in DN.

It is important to determine the biosynthesis process of collagen fibers to elucidate the mechanism by which granulation tissue is induced after injury. The purpose of this study is to investigate whether collagen microfibrils can be formed not only outside but also inside a cell. Fibroblast-like cells in granulation tissue resulting from incision and ligation were examined. The cells possessed vesicles containing collagen microfibrils. The vesicles were present in connection with Golgi apparatus or the rough endoplasmic reticulum. Furthermore, the vesicles were exhibited to be secretory granules with the secretory granule marker Rab3A. The fibroblast-like cells were also indicated to be myofibroblasts, using conventional transmission electron microscopy and immunoelectron microscopy for the myofibroblast marker alpha smooth muscle actin. In conclusion, it was demonstrated that collagen microfibrils could be formed in the cell in the case of collagen fiber overproduction.

The developmental mechanism of tubulointerstitial fibrosis in diabetic nephropathy (DN) has not been elucidated. Tubulointerstitial fibrosis, as well as glomerulosclerosis, occurs in DN. Myofibroblasts which overproduce extracellular matrix are present in the renal interstitium in diabetics, although they are almost never seen in normal kidneys. The myofibroblasts appear to originate from interstitial fibroblasts. In addition, transforming growth factor-beta1 (TGF-beta 1), which can evoke myofibroblast transformation, is detected in interstitial cells in the diabetic kidney, but not in the normal kidney. Taken together, these findings led us to speculate that TGF-beta 1 induces the transformation of interstitial fibroblasts into myofibroblasts, followed by tubulointerstitial fibrosis. Based on this speculation, we discuss the developmental mechanism of tubulointerstitial fibrosis in this review.