Urinary tract cytology showing variant morphology and divergent differentiation.

Urothelial carcinoma represents a diverse group of tumours with distinct histologic subtypes, each exhibiting unique cytomorphologic features, architectural growth patterns, and/or well-developed aberrant differentiation. In fact, there are more than 13 subtypes of urothelial carcinoma recognized in the 2022 WHO classification of tumours in the urinary tract. The identification of these subtypes is crucial for an accurate diagnosis of urothelial carcinoma, and many have important clinical implications. Variant/divergent features may coexist with conventional high-grade urothelial carcinoma (HGUC) or present with 100% variant morphology. In urinary tract cytology (UTC), urothelial carcinoma can display divergent differentiation, such as squamous, glandular, or small cell carcinoma differentiation. The use of cell block preparations and immunohistochemistry with available residual urine can enhance diagnostic accuracy. On the other hand, identifying urothelial carcinoma variants, including nested, micropapillary, and plasmacytoid subtypes, poses significant challenges in UTC. Many cases of these variants are only detected retrospectively after variant histology has been established from resection specimens. Moreover, some variants exhibit features inconsistent with the diagnostic criteria for HGUC according to the Paris System for Reporting Urinary Tract Cytology. Nevertheless, the rarity of pure variant morphology and the occurrence of some false negatives for these variant cases are essential to maintain the specificity of UTC overall. This review covers the histology, cytomorphology, and important clinical aspects observed in urothelial carcinoma exhibiting divergent differentiation and various urothelial carcinoma variants detected in UTC.

Effects of Heme Oxygenase-1 on c-Kit-Positive Cardiac Cells.

Heme oxygenase-1 (HO-1) is one of the most powerful cytoprotective proteins known. The goal of this study was to explore the effects of HO-1 in c-kit-positive cardiac cells (CPCs). LinNEG/c-kitPOS CPCs were isolated and expanded from wild-type (WT), HO-1 transgenic (TG), or HO-1 knockout (KO) mouse hearts. Compared with WT CPCs, cell proliferation was significantly increased in HO-1TG CPCs and decreased in HO-1KO CPCs. HO-1TG CPCs also exhibited a marked increase in new DNA synthesis during the S-phase of cell division, not only under normoxia (21% O2) but after severe hypoxia (1% O2 for 16 h). These properties of HO-1TG CPCs were associated with nuclear translocation (and thus activation) of Nrf2, a key transcription factor that regulates antioxidant genes, and increased protein expression of Ec-SOD, the only extracellular antioxidant enzyme. These data demonstrate that HO-1 upregulates Ec-SOD in CPCs and suggest that this occurs via activation of Nrf2, which thus is potentially involved in the crosstalk between two antioxidants, HO-1 in cytoplasm and Ec-SOD in extracellular matrix. Overexpression of HO-1 in CPCs may improve the survival and reparative ability of CPCs after transplantation and thus may have potential clinical application to increase efficacy of cell therapy.

Cytomorphology of monomorphic spindle epithelial tumor with thymus-like elements: A case with local recurrence after subtotal resection.

Spindle epithelial tumor with thymus-like elements (SETTLE) is a rare biphasic thyroid tumor with low malignant potential that has a distinct morphology. Despite fine needle aspiration (FNA) being a common method for evaluating thyroid nodules and lymph nodes, there are limited cytologic descriptions of SETTLE in the literature due to its rarity. As a result, SETTLE is frequently underdiagnosed or misdiagnosed as medullary carcinoma, thymoma, teratoma, synovial sarcoma, or solitary fibrous tumor, among others. We present a case of a 28-year-old man with a history of a hemithyroidectomy diagnosed as SETTLE found to have a neck nodule along the strap muscle suspicious for recurrence 5 years post-surgery. The ultrasound-guided FNA cytology specimen of the neck nodule showed loosely cohesive, monomorphous ovoid to spindled cells with scant cytoplasm and nuclei with fine to granular chromatin. In addition, there were occasional clusters of cells with a papillary configuration. The tumor cells were associated with magenta, amorphous extracellular material. Immunocytochemical staining of the cell block material revealed that tumor cells were positive for p63, cytokeratin AE1/3, and CK8/18 and negative for TTF-1 and thyroglobulin. Overall, the morphological and immunocytochemical findings were consistent with a local recurrence of SETTLE. The subsequent left anterior strap mass excision revealed a 4 cm encapsulated tumor consistent with SETTLE. Because ofits rarity and low level of awareness, SETTLE poses a diagnostic and therapeutic challenge. We herein present the cytologic findings of monomorphic SETTLE and highlight the potential cytomorphologic and immunophenotypic pitfalls. We also highlight how tumors with high-risk features can be a therapeutic challenge.

Pitfalls in Urinary Tract Cytopathology.

Urine cytopathology is a cost-effective method to diagnose and follow patients with high grade urothelial carcinoma (HGUC). However, some benign, reactive and metaplastic changes may mimic HGUC and pose a diagnostic challenge for cytopathologists. Summary: Our comprehensive review focuses on summarizing common pitfalls encountered in urine cytopathology, based largely on the experience of the senior author (AC) utilising the diagnostic criteria described in the 2nd edition of The Paris system (TPS) for reporting urinary tract cytopathology and in recent published literature. These include urothelial tissue fragments, instrumented samples, degenerative changes, treatment effects, viral cytopathic changes, iatrogenic and metaplastic changes. Our aim is to provide a clear understanding of these challenges to assist cytopathologists in making accurate diagnoses. Key Message: It's crucial for cytopathologists to recognize benign, reactive and metaplastic lesions that could resemble HGUC. Awareness of these cytological features is essential to minimise diagnostic errors.

Physiological Oxygen Tension Enhances Competence and Functional Properties of Murine Cardiac Mesenchymal Cells.

Cardiac mesenchymal cells (CMCs), a newly-discovered and promising type of progenitor cells, are effective in improving cardiac function in rodents after myocardial infarction. Stem/progenitor cells are usually cultured at atmospheric O2 tension (21%); however, the physiologic O2 tension in the heart is ~5%, raising the concern that 21% O2 may cause toxicity due to oxidative stress. Thus, we compared mouse CMCs cultured at 21% or 5% O2 beginning at passage 2. At passage 5, CMCs underwent severe hypoxic stress (1% O2 for 24 h). Compared with CMCs cultured at 21% O2, culture at 5% O2 consistently improved cell morphology throughout 5 passages, markedly decreased cell size, increased cell number, shortened cell doubling time, and dramatically reduced lactate dehydrogenase release from CMCs into culture media after hypoxic stress. Furthermore, culture at 5% O2 increased telomerase activity and telomere length, implying that 21% O2 tension impairs telomerase activity, resulting in telomere shortening and decreased cell proliferation. Thus far, almost all preclinical and clinical studies of cell therapy for the heart disease have used atmospheric (21%) O2 to culture cells. Our data challenge this paradigm. Our results demonstrate that, compared with 21% O2, 5% O2 tension greatly enhances the competence and functional properties of CMCs. The increased proliferation rate at 5% O2 means that target numbers of CMCs can be achieved with much less time and cost. Furthermore, since this increased proliferation may continue in vivo after CMC transplantation, and since cells grown at 5% O2 are markedly resistant to severe hypoxic stress, and thus may be better able to survive after transplantation into scarred regions of the heart where O2 is very low, culture at 5% O2 may enhance the reparative properties of CMCs (and possibly other cell types). In conclusion, our data support a change in the methods used to culture CMCs and possibly other progenitor cells.

Cardiac Mesenchymal Cells Cultured at Physiologic Oxygen Tension Have Superior Therapeutic Efficacy in Heart Failure Caused by Myocardial Infarction.

Stem/progenitor cells are usually cultured at atmospheric O2 tension (21%); however, since physiologic O2 tension in the heart is ∼5%, using 21% O2 may cause oxidative stress and toxicity. Cardiac mesenchymal cells (CMCs), a newly discovered and promising type of progenitor cells, are effective in improving left ventricle (LV) function after myocardial infarction (MI). We have previously shown that, compared with 21% O2, culture at 5% O2 increases CMC proliferation, telomerase activity, telomere length, and resistance to severe hypoxia in vitro. However, it is unknown whether these beneficial effects of 5% O2 in vitro translate into greater therapeutic efficacy in vivo in the treatment of heart failure. Thus, murine CMCs were cultured at 21% or 5% O2. Mice with heart failure caused by a 60-min coronary occlusion followed by 30 days of reperfusion received vehicle, 21% or 5% O2 CMCs via echocardiography-guided intraventricular injection. After 35 days, the improvement in LV ejection fraction effected by 5% O2 CMCs was > 3 times greater than that afforded by 21% O2 CMCs (5.2 vs. 1.5 units, P < 0.01). Hemodynamic studies (Millar catheter) yielded similar results both for load-dependent (LV dP/dt) and load-independent (end-systolic elastance) indices. Thus, two independent approaches (echo and hemodynamics) demonstrated the therapeutic superiority of 5% O2 CMCs. Further, 5% O2 CMCs, but not 21% O2 CMCs, significantly decreased scar size, increased viable myocardium, reduced LV hypertrophy and dilatation, and limited myocardial fibrosis both in the risk and non-infarcted regions. Taken together, these results show, for the first time, that culturing CMCs at physiologic (5%) O2 tension provides superior therapeutic efficacy in promoting cardiac repair in vivo. This concept may enhance the therapeutic potential of CMCs. Further, culture at 5% O2 enables greater numbers of cells to be produced in a shorter time, thereby reducing costs and effort and limiting cell senescence. Thus, the present study has potentially vast implications for the field of cell therapy.

Effects of Interferon Beta in COVID-19 adult patients: Systematic Review.

BACKGROUND: The high rate of transmission and infection of coronavirus disease 2019 (COVID-19) is a public health emergency of major epidemiological concern. No definitive treatments have been established, and vaccinations have only recently begun. We aim to review the efficacy and safety of Interferon Beta (IFN-ß) in patients who have a confirmed COVID-19 diagnosis. MATERIALS AND METHODS: A search from PubMed, Science Direct, Cochrane, and Clinicaltrials.gov databases were conducted from December 2019 to December 2020 to review the efficacy and safety of IFN-ß in adult patients with COVID-19 confirmed. We included randomized controlled trials, case reports, and experimental studies. Correspondences, letters, editorials, reviews, commentaries, case control, cross-sectional, and cohort studies that did not include any new clinical data were excluded. RESULTS: Of the 66 searched studies, 8 were included in our review. These studies demonstrated that although IFN-ß did not reduce the time to clinical response, there was an increase in discharge rate at day 14 and a decrease in mortality at day 28. The time to negative reverse transcription polymerase chain reaction (RT-PCR) was shown to be significantly shortened in patients receiving IFN-ß, along with a lower nasopharyngeal viral load. Further, patients receiving IFN-ß had a less significant rise in IL-6. IFN-ß was shown to decrease intensive care unit (ICU) admission rate, the requirement of invasive ventilation in severe cases, and improve the survival rate compared to control groups. There were no severe adverse events reported. Our review found that patients who received early treatment with IFN-ß experienced significantly reduced length of hospitalization, mortality, ICU admission, and mechanical ventilation. A greater chance of clinical improvement and improved imaging studies was noted in patients who received IFN-ß. There were no reported deaths associated with the addition of IFN-ß. Further randomized trials involving more significant sample sizes are needed to better understand the effect of IFN-ß on survival in COVID-19. CONCLUSION: This review identified encouraging data and outcomes of incorporating IFN-ß to treat COVID-19 patients. IFN-ß has been shown to decrease hospital stay's overall length and decrease the severity of respiratory symptoms when added to the standard of care. Also, in some studies, it has been demonstrated to reduce the length of ICU stay, enhance survival rate, and decrease the need for invasive mechanical ventilation. There were minor side effects reported (neuropsychiatric symptoms and hypersensitivity reaction). However, randomized clinical trials with a large sample size are needed to assess IFN-ß's benefit precisely.