Stem cell challenges and opportunities.

Hepatocyte-like cells (HLCs) generated from human pluripotent stem cells (PSCs) exhibit hepatocytic properties in vitro; however, their engraftment and functionality in vivo remain unsatisfactory. Despite optimization of differentiation protocols, HLCs did not engraft in a mouse model of liver injury. In contrast, organ-derived hepatocytes reproducibly formed colonies in the liver injury mouse model. As an extension of the phenomenon observed in hematopoietic stem cells giving rise to colonies within the spleen, commonly referred to as "colony-forming units in spleen (CFU-s)", we hypothesize that "colony-forming units in liver (CFU-L)" serves as a reliable indicator of stemness, engraftment, and functionality of hepatocytes. The uniform expression of the randomly inactivated gene in a single colony, as reported by Sugahara et al. 2022, suggests that the colonies generated by isolated hepatocytes likely originate from a single cell. We, therefore, propose that CFU-L can be used to quantify the number of "hepatocytes that engraft and proliferate in vivo" as a quantitative assay for stem cells that utilize colony-forming ability, similar to that observed in hematopoietic stem cells.

Weight of evidence approach using a TK gene mutation assay with human TK6 cells for follow-up of positive results in Ames tests: a collaborative study by MMS/JEMS.

BACKGROUND: Conflicting results between bacterial mutagenicity tests (the Ames test) and mammalian carcinogenicity tests might be due to species differences in metabolism, genome structure, and DNA repair systems. Mutagenicity assays using human cells are thought to be an advantage as follow-up studies for positive results in Ames tests. In this collaborative study, a thymidine kinase gene mutation study (TK6 assay) using human lymphoblastoid TK6 cells, established in OECD TG490, was used to examine 10 chemicals that have conflicting results in mutagenicity studies (a positive Ames test and a negative result in rodent carcinogenicity studies). RESULTS: Two of 10 test substances were negative in the overall judgment (20% effective as a follow-up test). Three of these eight positive substances were negative after the short-term treatment and positive after the 24 h treatment, despite identical treatment conditions without S9. A toxicoproteomic analysis of TK6 cells treated with 4-nitroanthranilic acid was thus used to aid the interpretation of the test results. This analysis using differentially expressed proteins after the 24 h treatment indicated that in vitro specific oxidative stress is involved in false positive response in the TK6 assay. CONCLUSIONS: The usefulness of the TK6 assay, by current methods that have not been combined with new technologies such as proteomics, was found to be limited as a follow-up test, although it still may help to reduce some false positive results (20%) in Ames tests. Thus, the combination analysis with toxicoproteomics may be useful for interpreting false positive results raised by 24 h specific reactions in the assay, resulting in the more reduction (> 20%) of false positives in Ames test.

Renal Failure Found during the Follow-up of Sarcoidosis: The Relevance of a Delay in the Diagnosis of Concurrent Hypercalcemia.

We herein present a case of relapsed sarcoidosis with a deteriorated renal function accompanied by hypercalcemia, nephrolithiasis, and a ureteral stone in a woman with a history of ocular sarcoidosis. The ocular involvement appeared to be well controlled for a long period of time with a topical ophthalmic steroid; however, we believe that the absence of apparent recrudescence could have led to the delay in our diagnosis of relapse of the disease during the follow-up period. The conundrums regarding longitudinal surveillance for both evaluating the disease activity and determining the necessity of therapeutics are also discussed.

Therapeutic Challenges to End-Stage Kidney Disease in a Patient with Tetralogy of Fallot.

In this report, we describe the case of an end-stage kidney disease patient with tetralogy of Fallot (TOF). A 33-year-old female with TOF was admitted to our hospital with complaints of general fatigue and appetite loss probably due to uremic milieu. She was ultimately treated with peritoneal dialysis (PD) with a favorable clinical course. TOF patients with chronic kidney disease are not exceptional, although the currently available information regarding the association between TOF and renal failure severe enough to require dialysis treatment is limited. We also discuss the complex processes of how and why PD was selected as a mode of chronic renal replacement therapy in this case.

Henoch-Schönlein purpura complicated with severe gastrointestinal bleeding.

Bleeding from the gastrointestinal tract is one of the common determinants of morbidity and mortality in the ordinary clinical setting. The gastrointestinal involvement of Henoch-Schönlein purpura (HSP) has often been described as self-limiting, with no long-term morbidity. In this report, we describe our experience with a male HSP patient who presented with abdominal pain, loss of appetite and deteriorated renal function associated with nephrotic syndrome. Despite the use of aggressive immunomodulatory treatments, including corticosteroids and plasmapheresis, he developed lethal gastrointestinal hemorrhage. We believe that the accumulation of more experience with additional cases similar to ours is mandatory for the establishment of optimal management for HSP patients with severe gastrointestinal manifestations.

Do we have to perform a renal biopsy? Clinical dilemmas in a case with nephrotic syndrome.

Renal biopsy is one of the pivotal diagnostic tools used in the field of nephrology. A morphological analysis of the kidney may also be of value for the overall management of patients with diabetic nephropathy. However, the indications for renal biopsy differ considerably among nephrologists, and no global consensus regarding performing this procedure among diabetic patients with various renal manifestations has yet been achieved. In this report, we would like to describe our serendipitous experience with a male type 2 diabetic patient presenting with nephrotic syndrome complicated by concurrent gastric carcinoma. We also discuss several conundrums that arose in the current case, which had an impact on our diagnostic and therapeutic decisions.

Anti-glomerular basement membrane glomerulonephritis complicated by thrombocytopenia.

Rapidly progressive glomerulonephritis (RPGN) is characterized by the rapid deterioration of the renal function associated with crescent formation on renal biopsies. This report describes a case of RPGN caused by anti-glomerular basement membrane (GBM) glomerulonephritis in an elderly man with severe thrombocytopenia and a platelet count of 1.4 × 10(4)/µL. Thrombotic microangiopathy (TMA) and heparin-induced thrombocytopenia (HIT) were implicated in the severe decrease in platelets. This report also discusses the pathological background and clinical management of TMA and HIT among patients with anti-GBM glomerulonephritis.

Characteristics of urinary and serum soluble Klotho protein in patients with different degrees of chronic kidney disease.

BACKGROUND: Klotho is a single-pass transmembrane protein, which appears to be implicated in aging. The purpose of the present study was to characterize the relationship between the soluble Klotho level and renal function in patients with various degrees of chronic kidney disease (CKD). METHODS: The levels of soluble Klotho in the serum and urine obtained from one hundred thirty-one CKD patients were determined by a sandwich enzyme-linked immunosorbent assay system. RESULTS: The amount of urinary excreted Klotho during the 24 hr period ranged from 1.6 to 5178 ng/day (median 427 ng/day; interquartile range [IR] 56.8-1293.1), and the serum Klotho concentration ranged from 163.9 to 2123.7 pg/ml (median 759.7 pg/ml; IR 579.5-1069.1). The estimated glomerular filtration rate (eGFR) was significantly correlated with the log-transformed values of the amount of 24 hr urinary excreted Klotho (r = 0.407, p < 0.01) and the serum Klotho levels (r = 0.232, p < 0.01). However, a stepwise multiple regression analysis identified eGFR to be a variable independently associated only with the log-transformed value of the amount of 24-hr urinary excreted Klotho but not with the log-transformed serum Klotho concentration. Despite the strong correlation between random urine protein-to-creatinine ratio and the 24 hr urinary protein excretion (r = 0.834, p < 0.01), a moderate linear association was observed between the log-transformed value of the amount of 24 hr urinary excreted Klotho and that of the urinary Klotho-to-creatinine ratio (Klotho/Cr) in random urine specimens (r = 0.726, p < 0.01). CONCLUSIONS: The amount of urinary Klotho, rather than the serum Klotho levels, should be linked to the magnitude of the functioning nephrons in CKD patients. The use of random urine Klotho/Cr as a surrogate for the amount of 24-hr urinary excreted Klotho needs to be evaluated more carefully.

Successful treatment of a mesangial proliferative glomerulonephritis with interstitial nephritis associated with Castleman's disease by an anti-interleukin-6 receptor antibody (tocilizumab).

We report a case of mesangial proliferative glomerulonephritis with interstitial nephritis associated with multicentric Castleman's disease (MCD) successfully treated with an anti-interleukin-6 receptor antibody (tocilizumab). This mesangial proliferative glomerulonephritis with interstitial nephritis was resistant to methylprednisolone treatment; however, it was markedly improved with tocilizumab, which was administered intravenously at a dose of 8 mg/kg every 2 weeks. These results suggest that tocilizumab is effective for the treatment of mesangial proliferative glomerulonephritis with interstitial nephritis associated with MCD.

Is there a link between diabetic glomerular injury and crescent formation? A case report and literature review.

Glomerular crescents are most commonly associated with rapidly progressive crescentic glomerulonephritis; however, they also develop in response to a wide range of primary and secondary glomerular injuries. Since various kind of glomerulopathies occasionally overlay diabetic glomerular injuries, the presence of crescents in renal biopsy specimens of diabetics may have stimulated a search for etiologies other than diabetes. In this report, we describe an unusual case of diabetic glomerulosclerosis with peculiar extracapillary proliferation. Although such a relationship has so far been ignored in most of the literature, the etiological linkage between diabetic glomerulosclerosis and the development of crescents may not be exceptional. We have reviewed the previous literature and herein discuss the pathological implications of the development of crescents in patients with diabetic glomerulosclerosis. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3950457896920255.

The relationship between the soluble Klotho protein and the residual renal function among peritoneal dialysis patients.

BACKGROUND: Klotho has been investigated as an anti-aging protein that is predominantly expressed in the distal convoluted tubules in the kidneys and in the choroid plexus of the brain. The purpose of the present study was to determine the relationship between the soluble form of Klotho and renal function in chronic peritoneal dialysis (PD) patients, a relationship which remains poorly understood. METHODS: The soluble Klotho levels in the serum, urine, and peritoneal dialysate obtained from thirty-six PD patients were determined by a sandwich enzyme-linked immunosorbent assay system. RESULTS: The amount of urinary excreted soluble Klotho over 24 h ranged from 1.54 to 1774.4 ng/day (median 303.2 ng/day; interquartile range [IR] 84.1-498.5), while the serum soluble Klotho concentration ranged from 194.4 to 990.4 pg/ml (mean 553.7 ± 210.4 pg/ml). The amount of urinary Klotho excretion was significantly correlated with residual renal function. However, there was no apparent correlation between the serum soluble Klotho levels and the residual renal function. Klotho was also detected in the 24-h dialysate collections. There was a significant correlation between the peritoneal Klotho excretion and the amount of albumin contained in the dialysate collections (r = 0.798, p < 0.01). CONCLUSIONS: The total amount of urinary excreted Klotho, but not the serum level of soluble Klotho, may be a potential biomarker for assessing the residual renal function among PD patients. Whether our findings are also valid for chronic kidney disease patients overall should therefore be evaluated in greater detail.

Membranous nephropathy in an HIV-positive patient complicated with hepatitis B virus infection.

In ordinary settings, human immunodeficiency virus (HIV)-associated nephropathy should be considered when HIV infection is associated with heavy proteinuria. On the other hand, hepatitis B virus (HBV) may also play a role in the development of glomerular injury among patients with HIV infection, since HIV and HBV infections commonly occur together due to shared modes of transmission. We present here a case of nephrotic syndrome in an HIV-positive patient complicated with HBV infection. A renal biopsy revealed sparse granular deposits of immunoglobulin G in the subepithelial region, consistent with membranous nephropathy (MN) stage I. Moreover, immunostaining exhibited weak anti-hepatitis B core activity within glomeruli. These results led us to consider that HBV-associated MN might play a role in the development of nephrotic syndrome. Although anti-viral treatment for patients with HBV-associated MN has been suggested to be clinically effective, the use of two anti-HIV agents (tenofovir and emtricitabine), both of which have anti-HBV activities, was not effective for the patient's nephrotic syndrome, despite obtaining a decrease in the serum HBV-DNA levels. A lack of prospective data suggests that many decisions on the treatment of glomerulopathies with HIV infections are potentially empirical. Obviously, further studies and accumulated clinical experience are required to better determine the pathogenesis and management of HBV-associated MN among patients with HIV infections.

Differential transcriptional regulation of two distinct S-adenosylmethionine synthetase genes (SAM1 and SAM2) of Saccharomyces cerevisiae.

Expression of a number of genes encoding enzymes involved in phospholipid biosynthesis in yeast Saccharomyces cerevisiae is known to be repressed on the addition of myo-inositol and choline to the culture medium (inositol-choline regulation). All genes subject to this inositol-choline regulation have an octamer sequence 5'-CATRTGAA-3' in their upstream regions and those octamer sequences play an important role in this regulation. To confirm the role of the octamer sequence further, we studied the transcriptional regulation of two distinct S-adenosylmethionine synthetase genes (SAM1 and SAM2) of S. cerevisiae. Quantitative RT-PCR analysis showed that only the SAM2 gene was subject to the inositol-choline regulation, consistent with the fact that only the SAM2 gene has two octamer sequences in its upstream region. Furthermore, functional promoter analysis revealed that the proximal octamer sequence of the SAM2 gene has an essential role for this regulation.