Long-term viable chimeric nephrons generated from progenitor cells are a reliable model in cisplatin-induced toxicity.

Kidney organoids have shown promise as evaluation tools, but their in vitro maturity remains limited. Transplantation into adult mice has aided in maturation; however, their lack of urinary tract connection limits long-term viability. Thus, long-term viable generated nephrons have not been demonstrated. In this study, we present an approachable method in which mouse and rat renal progenitor cells are injected into the developing kidneys of neonatal mice, resulting in the generation of chimeric nephrons integrated with the host urinary tracts. These chimeric nephrons exhibit similar maturation to the host nephrons, long-term viability with excretion and reabsorption functions, and cisplatin-induced renal injury in both acute and chronic phases, as confirmed by single-cell RNA-sequencing. Additionally, induced human nephron progenitor cells differentiate into nephrons within the neonatal kidneys. Collectively, neonatal injection represents a promising approach for in vivo nephron generation, with potential applications in kidney regeneration, drug screening, and pathological analysis.

Evaluation of the ability of human induced nephron progenitor cells to form chimeric renal organoids using mouse embryonic renal progenitor cells.

The number of patients with end-stage renal failure is increasing annually worldwide and the problem is compounded by a shortage of renal transplantation donors. In our previous research, we have shown that transplantation of renal progenitor cells into the nephrogenic region of heterologous fetuses can induce the development of nephrons. We have also developed transgenic mice in which specific renal progenitor cells can be removed by drugs. By combining these two technologies, we have succeeded in generating human-mouse chimeric kidneys in fetal mice. We hope to apply these technologies to regenerative medicine. The quality of nephron progenitor cells (NPCs) derived from human pluripotent stem cells is important for the generation of chimeric kidneys, but there is currently no simple evaluation system for the chimerogenic potential of human NPCs. In this study, we focused on the fact that the re-aggregation of mouse renal progenitor cells can be used for nephron formation, even when merged into single cells. First, we examined the conditions under which nephron formation is likely to occur in mice during re-aggregation. Next, to improve the differentiation potential of human NPCs derived from pluripotent stem cells, NPCs were sorted using Integrin subunit alpha 8 (ITGA8). Finally, we demonstrated chimera formation between different species by mixing mouse cells with purified, selectively-induced human NPCs under optimum conditions. We observed these chimeric organoids at different time points to learn about these human-mouse chimeric structures at various stages of renal development. We found that the rate of chimera formation was affected by the purity of the human NPCs and the cell ratios used. We demonstrated that chimeric nephrons can be generated using a simple model, even between distant species. We believe that this admixture of human and mouse renal progenitor cells is a promising technology with potential application for the evaluation of the chimera formation abilities of NPCs.

Characteristics of Gastric Stasis due to Deformation after Endoscopic Submucosal Dissection in the Lower Part of the Stomach.

INTRODUCTION: Gastric stasis due to deformation occurs after endoscopic submucosal dissection in the lower part of the stomach. Endoscopic balloon dilation can improve gastric stasis due to stenosis; however, endoscopic balloon dilation cannot improve gastric stasis due to deformation. Furthermore, the characteristics of gastric stasis due to deformation are unknown. This study aimed to evaluate the characteristics of gastric stasis due to deformation after endoscopic submucosal dissection in the lower part of the stomach, focusing on the differences between stenosis and deformation. METHODS: We retrospectively reviewed 41 patients with gastric stasis after endoscopic submucosal dissection in the lower part of the stomach. We evaluated the characteristics of cases with gastric stasis due to deformation, such as the risk factors of deformation and the rate of deformation in each group with risk factors. RESULTS: Deformation was observed in 12% (5/41) of the patients with gastric stasis. All cases of deformation had a circumferential extent of the mucosal defect greater than 3/4. The number of cases with pyloric dissection was significantly lower in the deformation group than in the non-deformation group (0% vs. 72%; p = 0.004). The deformation group also had a significantly higher number of cases with angular dissection than the non-deformation group (100% vs. 17%; p < 0.001). Moreover, the deformation cases had a significantly larger specimen diameter (p < 0.001). Deformation was observed only in cases with angular and non-pyloric dissections. Deformation was not observed in cases with angular and pyloric dissections. CONCLUSIONS: All cases of gastric stasis due to deformation had a circumferential extent of the mucosal defect greater than 3/4. Deformation was also likely to occur in cases with a larger dissection that exceeded the angular region without pyloric dissection.

A Pregnant Woman with IgA Nephropathy Showing Histological Preeclampsia Findings without Hypertension Treated with Steroids: A Case Report and Literature Review.

A 35-year-old woman pregnant with twins developed nephrotic syndrome (NS) at 33 weeks' gestation, but her blood pressure remained within the normal range throughout gestation and puerperium. At 34 weeks' gestation, she delivered healthy twins via Caesarean section. After delivery, she developed massive proteinuria (21.1 g/day) and severe hypoalbuminemia (1.0 g/dL). A renal biopsy performed 19 days after delivery revealed IgA nephropathy (IgAN) and preeclampsia. She was treated with steroids, and the NS gradually resolved. This is a rare case of massive gestational proteinuria with IgAN and preeclampsia pathologically that did not meet the clinical criteria for preeclampsia.

Development of a Cryopreservation Technique for Xenogeneic Kidney Grafts: Evaluation Using a Mouse Model.

To align the xeno-metanephros and renal progenitor cell timing for transplantation treatments, cryopreservation techniques and an efficient transportation of regenerated renal products such as xeno-metanephroi and renal progenitor cells should be established. Therefore, we propose a novel method of xenogeneic regenerative medicine for patients with chronic kidney disease by grafting porcine fetal kidneys injected with human renal progenitor cells. To develop a useful cryopreserve system of porcine fetal kidney and human renal progenitor cells, we examined the cryopreservation of a fetal kidney implanted with renal progenitor cells in a mouse model. First, we developed a new method for direct cell injection under the capsule of the metanephros using gelatin as a support for unzipped fetal kidneys. Then, we confirmed in vitro that the nephrons derived from the transplanted cells were regenerated even after cryopreservation before and after cell transplantation. Furthermore, the cryopreserved chimeric metanephroi grew, and regenerated nephrons were observed in NOD. We confirmed that even in cryopreserved chimeric metanephroi, transplanted cell-derived nephrons as well as fresh transplants grew.

Generation of functional chimeric kidney containing exogenous progenitor-derived stroma and nephron via a conditional empty niche.

Generation of new kidneys can be useful in various research fields, including organ transplantation. However, generating renal stroma, an important component tissue for structural support, endocrine function, and kidney development, remains difficult. Organ generation using an animal developmental niche can provide an appropriate in vivo environment for renal stroma differentiation. Here, we generate rat renal stroma with endocrine capacity by removing mouse stromal progenitor cells (SPCs) from the host developmental niche and transplanting rat SPCs. Furthermore, we develop a method to replace both nephron progenitor cells (NPCs) and SPCs, called the interspecies dual replacement of the progenitor (i-DROP) system, and successfully generate functional chimeric kidneys containing rat nephrons and stroma. This method can generate renal tissue from progenitors and reduce xenotransplant rejection. Moreover, it is a safe method, as donor cells do not stray into nontarget organs, thus accelerating research on stem cells, chimeras, and xenotransplantation.

Chest computer tomography is safe without additional interrogation or monitoring for modern cardiac implantable electrical devices.

INTRODUCTION: Whether diagnostic computed tomography (CT) scans to cardiac implantable electronic devices (CIED) is safe in recent models remains unknown. METHODS: A two-centers observational study. Over 14 years, consecutive 2362 chest CT scans (1666 pacemakers [PMs], 145 cardiac resynchronization therapy PM, 316 implantable cardioverter-defibrillator, and 233 cardiac resynchronization therapy defibrillator) were interrogated and monitored upon imaging. RESULTS: Electromagnetic interference occurred only in a few old models: InSync 8040 (n = 14), InSync III Marquis (n = 1), and Kappa (n = 4), which resulted no adverse events. CONCLUSION: CIEDs, especially recent ones, are confirmed safe on chest CT.

Generation of heterozygous PKD1 mutant pigs exhibiting early-onset renal cyst formation.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease, manifesting as the progressive development of fluid-filled renal cysts. In approximately half of all patients with ADPKD, end-stage renal disease results in decreased renal function. In this study, we used CRISPR-Cas9 and somatic cell cloning to produce pigs with the unique mutation c.152_153insG (PKD1insG/+). Pathological analysis of founder cloned animals and progeny revealed that PKD1insG/+ pigs developed many pathological conditions similar to those of patients with heterozygous mutations in PKD1. Pathological similarities included the formation of macroscopic renal cysts at the neonatal stage, number and cystogenic dynamics of the renal cysts formed, interstitial fibrosis of the renal tissue, and presence of a premature asymptomatic stage. Our findings demonstrate that PKD1insG/+ pigs recapitulate the characteristic symptoms of ADPKD.

Clinical Impact of Different Reconstruction Methods on Remnant Gastric Cancer at the Anastomotic Site after Distal Gastrectomy.

BACKGROUND/AIMS: The anastomotic site after distal gastrectomy is the area most affected by duodenogastric reflux. Different reconstruction methods may affect the lesion characteristics and treatment outcomes of remnant gastric cancers at the anastomotic site. We retrospectively investigated the clinicopathologic and endoscopic submucosal dissection outcomes of remnant gastric cancers at the anastomotic site. METHODS: We recruited 34 consecutive patients who underwent endoscopic submucosal dissection for remnant gastric cancer at the anastomotic site after distal gastrectomy. Clinicopathology and treatment outcomes were compared between the Billroth II and non-Billroth II groups. RESULTS: The tumor size in the Billroth II group was significantly larger than that in the non-Billroth II group (22 vs. 19 mm; p=0.048). More severe gastritis was detected endoscopically in the Billroth II group (2 vs. 1.33; p=0.0075). Moreover, operation time was longer (238 vs. 121 min; p=0.004) and the frequency of bleeding episodes was higher (7.5 vs. 3.1; p=0.014) in the Billroth II group. CONCLUSION: Compared to remnant gastric cancers in non-Billroth II patients, those in the Billroth II group had larger lesions with a background of severe remnant gastritis. Endoscopic submucosal dissection for remnant gastric cancers in Billroth II patients involved longer operative times and more frequent bleeding episodes than that in patients without Billroth II.

Immunopathological analysis of the expression of glomerular exostosin 1 and exostosin 2 in Japanese patients with lupus nephritis.

Exostosin 1 and exostosin 2 (EXT1/EXT2) on glomerular basement membrane (GBM) were recently reported as novel putative antigens in secondary membranous nephropathy with autoimmune disease. However, the clinical significance of glomerular EXT1/EXT2 remains elusive in patients with lupus nephritis (LN). The immunofluorescence staining pattern of glomerular EXT1/EXT2 is also undetermined in membranous LN (MLN) or proliferative LN (PLN). We cross-sectionally analyzed patients with MLN (pure class V, n = 11) and PLN (class III, IV, and mixed class III/IV + V, n = 22) who underwent renal biopsies between 2010 and 2020 at Showa University Hospital. Glomerular EXT1/EXT2 expressions were evaluated by immunofluorescence. T-helper (Th) cell-related serum inflammatory cytokines were measured using enzyme-linked immunosorbent assay. The positivity for both EXT1/EXT2 was higher in patients with MLN than PLN (90.9% vs 63.6%, P = 0.212). MLN showed global and bright granular EXT1/EXT2 expressions along GBM, while PLN showed segmental and moderate expressions on GBM. Additionally, glomerular EXT1/EXT2 positivity was not associated with the degree of proteinuria or renal function in MLN and PLN patients, but the levels of serum anti-dsDNA antibody and circulating immune complexes were lower in patients with EXT1/EXT2-positive MLN than EXT1/EXT2-negative PLN. Moreover, serum complement levels and IL-4/IFN-γ ratios were elevated in EXT1/EXT2-positive MLN than EXT1/EXT2-negative PLN. Collectively, immunofluorescence staining for glomerular EXT1/EXT2 had characteristic patterns between MLN and PLN. Glomerular EXT1/EXT2 expressions tended to be high in Th2-dominant MLN patients without severe hypocomplementemia and elevated autoantibodies. Thus, EXT1/EXT2 might be involved in the unique developmental mechanism of MLN.

Timing of pyloric stenosis and effectiveness of endoscopic balloon dilation after pyloric endoscopic submucosal dissection.

BACKGROUND AND AIM: There have been studies on risk factors for stenosis after pyloric endoscopic submucosal dissection (ESD). However, the most appropriate strategies for the management of cases with these risk factors have not been established. This study aimed to investigate post-ESD management by evaluating the timing of stenosis and the effectiveness of endoscopic balloon dilation (EBD) after pyloric ESD. METHODS: We retrospectively reviewed cases of pyloric ESD. We first reassessed risk factors for stenosis in multivariate analysis and receiver operating characteristic curve and defined patients with the identified risk factors as the risk group. The primary outcome was the timing of stenosis in the risk group assessed by the Kaplan-Meier method. RESULTS: We reviewed 159 cases with pyloric ESD and observed pyloric stenosis in 25 cases. Cases with circumferential mucosal defect ≥ 76% were identified as the risk group. The stenosis-free probability in the risk group was 97% (95% confidence interval [CI]: 79-100%), 94% (95% CI: 76-98%), and 85% (95% CI: 66-93%) on days 7, 14, and 21, respectively. It decreased every week thereafter and did not significantly change after day 56. Twenty-three stenosis cases, except for conservative improvement, including six whole circumferential pyloric ESD cases, were improved by EBD without complications. CONCLUSIONS: Post-ESD stenosis often developed from the third to the eighth week. In all pyloric ESD cases, including whole circumferential pyloric ESD cases, pyloric stenosis was improved following EBD without complications.

Techniques of orthotopic renal transplantation. II. Size-matched porcine grafts in monkey recipients.

PURPOSE: As a classical xenotransplantation model, porcine kidneys have been transplanted into the lower abdomen of non-human primates. However, we have improved upon this model by using size-matched grafting in the orthotopic position. The beneficial aspects and surgical details of our method are reported herein. METHODS: Donors were two newborn pigs (weighting 5 to 6 kg) and recipients were two cynomolgus monkeys (weighting, approximately, 7 kg). After bilateral nephrectomy, kidneys were cold-transported in Euro-Collins solution. The porcine kidney was transplanted to the site of a left nephrectomy and fixed to the peritoneum. RESULTS: Kidneys transplanted to the lower abdomen by the conventional method were more susceptible to torsion of the renal vein (two cases). In contrast, early-stage blood flow insufficiency did not occur in orthotopic transplants of theleft kidney. CONCLUSIONS: Size-matched porcine-primate renal grafting using our method of transplanting tothe natural position of the kidneys contributes to stable post-transplant blood flow to the kidney.

In vivo regeneration of neo-nephrons in rodents by renal progenitor cell transplantation.

Renal progenitor cells induced from pluripotent stem cells have attracted attention as a cell source for organ regeneration. Here, we report an in vivo protocol for the regeneration of urine-producing nephrons, i.e., neo-nephrons, in mice. We outline steps to transplant exogenous renal progenitor cells into the nephrogenic zone of transgenic mice and subsequently analyze these neo-nephrons. For complete details on the use and execution of this protocol, please refer to Fujimoto et al. (2020).

Reno-protective effect of IL-34 inhibition on cisplatin-induced nephrotoxicity in mice.

INTRODUCTION: Interleukin-34 (IL-34) shares a receptor (cFMS) with colony stimulating factor-1 (CSF-1), and these two ligands mediate macrophage proliferation. However, in contrast to CSF-1, the influence of IL-34 on tubular epithelial cells (TECs) injury remains unclear. We investigated the physiological effects of IL-34 on TEC damage caused by cisplatin nephrotoxicity (CP-N). METHODS: Mice were administered anti-mouse IL-34 antibody (anti-IL-34 Ab; 400 ng/kg) or vehicle from 1 day before and up to 2 days after CP-N induction. In vitro, mouse renal proximal TECs (MRPTEpiC) were cultured to analyze the inhibitory effects of IL-34 on CP-induced TEC apoptosis. RESULTS: Compared to vehicle treatment, anti-IL-34 Ab treatment significantly suppressed the intra-renal expression of IL-34 and its two receptors, cFMS and PTP-ζ, and significantly improved renal function, ameliorated tubulointerstitial injury, suppressed macrophage infiltration, and reduced apoptotic cell numbers in CP-N mice. It also significantly reduced the renal transcript levels of Kim-1, MIP-1/CCL3, TNF-α, and Bax in CP-N mice. Furthermore, anti-IL-34 Ab-treated CP-N mice showed less renal infiltration of F4/80+TNF-α+ cells. In vitro, stimulation with CP induced the expression of IL-34 and its two receptors in MRPTEpiC. Anti-IL-34 Ab treatment significantly suppressed CP-induced Bax expression with the degradation of ERK1/2 phosphorylation in damaged MRPTEpiC. CONCLUSIONS: IL-34 secreted from damaged TECs appeared to be involved in the progression of CP-N. Inhibition of IL-34 with neutralizing antibody directly prevented CP-induced TEC apoptosis by inhibiting the phosphorylation of ERK 1/2. Blocking of IL-34 appears to suppress the proliferation of cytotoxic macrophages, which indirectly attenuates CP-N. Thus, IL-34 represents a potential therapeutic target for TEC injury, and the inhibition of IL-34 might have a reno-protective effect.

Tumoral calcinosis due to severe hyperphosphatemia and secondary hyperparathyroidism without vascular calcification in a hemodialysis patient.

We report a case of a 32-year-old man who was undergoing chronic hemodialysis and had hyperphosphatemia and secondary hyperparathyroidism (SHPT) with multiple tumoral calcinosis (TC) lesions refractory to drug therapy. Total parathyroidectomy and autotransplantation were performed, and he recovered from TC within 3 months. Several soft-tissue calcifications were present, but neither computed tomography (CT) before diagnosis nor CT performed 12 months after surgery detected evidence of vascular calcification (VC), despite persistence of hyperphosphatemia. This patient had a high calcium (Ca) × phosphate (P) product and calciprotein particles, and high serum Ca and P levels are important risk factors for both TC and VC. P plays a crucial role in regulation of VC, but the absence of VC in our case suggests a specific circumstance in which VC does not progress even under a high phosphatemic state, and that P alone may be insufficient for VC progression. TC in our patient was probably due to severe SHPT and continuous high serum P and Ca × P product levels, but the absence of VC suggests that the pathophysiologic process leading to VC requires further investigation, particularly in chronic kidney disease.

A case of intravascular large B-cell lymphoma with renal involvement presenting with elevated serum ANCA titers.

We report the first case of intravascular large B-cell lymphoma (IVLBCL) presenting with vasculitis-like symptoms and elevated serum levels of anti-neutrophil cytoplasmic antibody (ANCA) diagnosed by renal biopsy. The patient exhibited low-grade fever, systemic inflammatory reactions, multiple lung lesions, and persistent proteinuria, which were closely correlated with changes in serum titers of proteinase-3- and myeloperoxidase-ANCA. Preemptive therapy with prednisolone alone partially attenuated these symptoms. Renal biopsy did not reveal histopathological findings suggestive of granulomatous or microscopic polyangiitis. Glomerular and peritubular capillaries were diffusely occluded by CD20-positive large atypical mononuclear cells, with focal foot process effacement of podocytes in the glomeruli. Based on the specific immunophenotype of infiltrated atypical cells, the patient was diagnosed with IVLBCL. Chemotherapy regimens for IVLBCL improved clinical symptoms and led to remission of proteinuria. The ANCA titers decreased in parallel with reductions in the serum levels of the soluble interleukin-2 receptor, suggestive of an association between changes in ANCA levels and IVLBCL-related vascular injuries.

Techniques of orthotopic renal transplantation. II. Size-matched porcine grafts in monkey recipients

ABSTRACT Purpose As a classical xenotransplantation model, porcine kidneys have been transplanted into the lower abdomen of non-human primates. However, we have improved upon this model by using size-matched grafting in the orthotopic position. The beneficial aspects and surgical details of our method are reported herein. Methods Donors were two newborn pigs (weighting 5 to 6 kg) and recipients were two cynomolgus monkeys (weighting, approximately, 7 kg). After bilateral nephrectomy, kidneys were cold-transported in Euro-Collins solution. The porcine kidney was transplanted to the site of a left nephrectomy and fixed to the peritoneum. Results Kidneys transplanted to the lower abdomen by the conventional method were more susceptible to torsion of the renal vein (two cases). In contrast, early-stage blood flow insufficiency did not occur in orthotopic transplants of theleft kidney. Conclusions Size-matched porcine-primate renal grafting using our method of transplanting tothe natural position of the kidneys contributes to stable post-transplant blood flow to the kidney.

Generation of Human Renal Vesicles in Mouse Organ Niche Using Nephron Progenitor Cell Replacement System.

Animal fetuses may be used for the regeneration of human organs. We have previously generated a transgenic mouse model that allows diphtheria toxin (DT)-induced ablation of Six2-positive nephron progenitor cells (NPCs). Elimination of existing native host NPCs enables their replacement with donor NPCs, which can generate neo-nephrons. However, this system cannot be applied to human NPCs, because DT induces apoptosis in human cells. Therefore, the present study presents a transgenic mouse model for the ablation of NPCs using tamoxifen, which does not affect human cells. Using this system, we successfully regenerate interspecies neo-nephrons, which exhibit urine-producing abilities, from transplanted rat NPCs in a mouse host. Transplantation of human induced pluripotent stem cell (iPSC)-derived NPCs results in differentiation into renal vesicles, which connect to the ureteric bud of the host. Thus, we demonstrate the possibility of the regeneration of human kidneys derived from human iPSC-derived NPCs via NPC replacement.