Evaluation of glomerular sirtuin-1 and claudin-1 in the pathophysiology of nondiabetic focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is the leading cause of nephrotic syndrome, which is characterized by podocyte injury. Given that the pathophysiology of nondiabetic glomerulosclerosis is poorly understood and targeted therapies to prevent glomerular disease are lacking, we decided to investigate the tight junction protein claudin-1 and the histone deacetylase sirtuin-1 (SIRT1), which are known to be involved in podocyte injury. For this purpose, we first examined SIRT1, claudin-1 and podocin expression in kidney biopsies from patients diagnosed with nondiabetic FSGS and found that upregulation of glomerular claudin-1 accompanies a significant reduction in glomerular SIRT1 and podocin levels. From this, we investigated whether a small molecule activator of SIRT1, SRT1720, could delay the onset of FSGS in an animal model of adriamycin (ADR)-induced nephropathy; 14 days of treatment with SRT1720 attenuated glomerulosclerosis progression and albuminuria, prevented transcription factor Wilms tumor 1 (WT1) downregulation and increased glomerular claudin-1 in the ADR + SRT1720 group. Thus, we evaluated the effect of ADR and/or SRT1720 in cultured mouse podocytes. The results showed that ADR [1 µM] triggered an increase in claudin-1 expression after 30 min, and this effect was attenuated by pretreatment of podocytes with SRT1720 [5 µM]. ADR [1 µM] also led to changes in the localization of SIRT1 and claudin-1 in these cells, which could be associated with podocyte injury. Although the use of specific agonists such as SRT1720 presents some benefits in glomerular function, their underlying mechanisms still need to be further explored for therapeutic use. Taken together, our data indicate that SIRT1 and claudin-1 are relevant for the pathophysiology of nondiabetic FSGS.

Understanding yellow fever-associated myocardial injury: an autopsy study.

BACKGROUND: Yellow fever (YF) is a viral hemorrhagic fever, endemic in parts of South America and Africa. There is scarce evidence about the pathogenesis of the myocardial injury. The objective of this study is to evaluate the cardiac pathology in fatal cases of YF. METHODS: This retrospective autopsy study included cases from the São Paulo (Brazil) epidemic of 2017-2019. We reviewed medical records and performed cardiac tissue histopathological evaluation, electron microscopy, immunohistochemical assays, RT-qPCR for YF virus (YFV)-RNA, and proteomics analysis on inflammatory and endothelial biomarkers. FINDINGS: Seventy-three confirmed YF cases with a median age of 48 (34-60) years were included. We observed myocardial fibrosis in 68 (93.2%) patients; cardiomyocyte hypertrophy in 68 (93.2%); endothelial alterations in 67 (91.8%); fiber necrosis in 50 (68.5%); viral myocarditis in 9 (12.3%); and secondary myocarditis in 5 (6.8%). Four out of five patients with 17DD vaccine-associated viscerotropic disease presented with myocarditis. The cardiac conduction system showed edema, hemorrhages and endothelial fibrinoid necrosis. Immunohistochemistry detected CD68-positive inflammatory interstitial cells and YFV antigens in endothelial and inflammatory cells. YFV-RNA was detected positive in 95.7% of the cardiac samples. The proteomics analysis demonstrated that YF patients had higher levels of multiple inflammatory and endothelial biomarkers in comparison to cardiovascular controls, and higher levels of interferon gamma-induced protein 10 (IP-10) in comparison to sepsis (p = 0.01) and cardiovascular controls (p < 0.001) in Dunn test. INTERPRETATION: Myocardial injury is frequent in severe YF, due to multifactorial mechanisms, including direct YFV-mediated damage, endothelial cell injury, and inflammatory response, with a possible prominent role for IP-10. FUNDING: This study was funded by Fundação de Amparo à Pesquisa do Estado de São Paulo, Bill and Melinda Gates Foundation, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

Bevacizumab-Associated Thrombotic Microangiopathy Treated with Eculizumab: A Case Report.

BACKGROUND Bevacizumab is an approved targeted therapy for metastatic cancer treatment. It can have adverse effects on multiple organs. Despite its low incidence, thrombotic microangiopathy (TMA) is the most severe complication. TMA has been associated with complement dysregulation, and treatment with eculizumab can be effective, despite the paucity of literature on eculizumab therapy for bevacizumab-associated TMA. To date, 10 cases have been reported, with less than half of them including a kidney biopsy. We present a new case of bevacizumab-associated TMA successfully treated with eculizumab, along with kidney biopsy records and an overview of mechanisms underlying TMA development in bevacizumab-treated patients. CASE REPORT A female patient diagnosed with metastatic breast cancer who was treated with bevacizumab in conjunction with chemotherapy was admitted to the hospital for acute kidney injury requiring hemodialysis, microangiopathic hemolytic anemia, and thrombocytopenia. TMA was diagnosed and was later confirmed by a kidney biopsy. Primary causes for TMA, such as ADAMTS13 deficiency and shiga toxin associated hemolytic-uremic syndrome, were ruled out, and the patient's condition was ultimately found to be triggered by exposure to bevacizumab. After discontinuing bevacizumab and receiving 4 weekly doses of eculizumab, kidney function and hematological parameters improved. CONCLUSIONS Bevacizumab-associated TMA can be reversed or attenuated in some patients with the use of eculizumab (inhibiting complement system overactivation), possibly reducing time to recovery, with fewer long-term sequelae. This additional case encourages future clinical trials to evaluate the safety and efficacy of eculizumab in cases of TMA associated with bevacizumab.

Time to Recurrence as a Prognostic Factor in Parathyroid Carcinoma.

Background: Parathyroid carcinoma (PC) is a rare and challenging disease without clearly understood prognostic factors. Adequate management can improve outcomes. Characteristics of patients treated for PC over time and factors affecting prognosis were analyzed. Methods: Retrospective cohort study including surgically treated patients for PC between 2000 and 2021. If malignancy was suspected, free-margin resection was performed. Demographic, clinical, laboratory, surgical, pathological, and follow-up characteristics were assessed. Results: Seventeen patients were included. Mean tumor size was 32.5 mm, with 64.7% staged as pT1/pT2. None had lymph node involvement at admission, and 2 had distant metastases. Parathyroidectomy with ipsilateral thyroidectomy was performed in 82.2%. Mean postoperative calcium levels were different between patients who developed recurrence vs those who did not (P = .03). Six patients (40%) had no recurrence during follow-up, 2 (13.3%) only regional, 3 (20%) only distant, and 4 (26.6%) both regional and distant. At 5 and 10 years, 79% and 56% of patients were alive, respectively. Median disease-free survival was 70 months. Neither Tumor, Nodule, Metastasis system nor largest tumor dimension (P = .29 and P = .74, respectively) were predictive of death. En bloc resection was not superior to other surgical modalities (P = .97). Time between initial treatment and development of recurrence negatively impacted overall survival rate at 36 months (P = .01). Conclusion: Patients with PC can survive for decades and have indolent disease course. Free margins seem to be the most important factor in initial surgery. Recurrence was common (60%), but patients with disease recurrence within 36 months of initial surgery had a lower survival rate.

Chronic exposure to cigarette smoke transiently worsens the disease course in a mouse model of pulmonary paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) may present as an acute/subacute clinical form, characterized by a progressive disease arising from the airborne initial infection, or, most often, as an asymptomatic or subclinical infection that may manifest later during an individual's life, the chronic form. Epidemiological studies show the existence of a strong association between smoking and the development of the chronic form. Current evidence demonstrates that cigarette smoke (CS) has immunosuppressive properties that could be implicated in the increasing susceptibility to the chronic form of PCM. To address this issue, we developed a murine model of a non-progressive pulmonary form of PCM that was exposed to CS at a magnitude that mimicked a moderate smoker. The chronic CS exposure started after 2 weeks and lasted up until 20 weeks post-infection, with the aim of mimicking human natural history, since it is estimated that individuals from endemic areas are infected early in life. The control group consisted of infected but not CS-exposed mice. We assessed the lung fungal burden (colony forming units [CFU]) and the area affected by the granulomatous inflammatory response, fungal dissemination to spleen and liver, and, by immunohistochemistry, the presence of CD4 and CD8 lymphocytes, CD68 and MAC-2 macrophages, and IFN-γ, IL-10 and TNF expressing cells within the granulomatous response. We detected a CS effect as early as 2 weeks after exposure (four weeks post-infection) when the lung CFU of exposed animals was significantly higher than in their non-exposed counterparts. At 12 weeks, the CS-exposed animals presented a more severe disease, as witnessed by the persistent higher lung fungal load (although it did not reach statistical significance [ p = 0.054]), greater dissemination to other organs, greater affected area of the lung, decreased IFN-γ/IL-10 ratio, and higher TNF expression within the granulomas, compared with CS-non-exposed mice. The number of CD4 and CD8 lymphocytes infiltrating the granulomas was similar between both mice groups, but there was a decrease in the number of MAC-2+ macrophages. No difference was noted in the CD68+ macrophage number. However, the follow-up in week 20 showed that the immunological effects of exposure to CS ceased, with both CS and NCS mice showing the same infectious features, i.e., a trend for resolution of the infection. In conclusion, we show that chronic CS-exposure alters the course of the disease in an experimental model of subclinical pulmonary PCM, confirming the epidemiological link between CS-exposure and the chronic form of PCM. However, we also show that this effect is transitory, being detected between 4- and 12-weeks post-infection but not thereafter. The possible immune mechanisms that mediate this effect and the reasons for its transitory effect are discussed.

Understanding Sabiá virus infections (Brazilian mammarenavirus).

BACKGROUND: Only two naturally occurring human Sabiá virus (SABV) infections have been reported, and those occurred over 20 years ago. METHODS: We diagnosed two new cases of SABV infection using metagenomics in patients thought to have severe yellow fever and described new features of histopathological findings. RESULTS: We characterized clinical manifestations, histopathology and analyzed possible nosocomial transmission. Patients presented with hepatitis, bleeding, neurological alterations and died. We traced twenty-nine hospital contacts and evaluated them clinically and by RT-PCR and neutralizing antibodies. Autopsies uncovered unique features on electron microscopy, such as hepatocyte "pinewood knot" lesions. Although previous reports with similar New-World arenavirus had nosocomial transmission, our data did not find any case in contact tracing. CONCLUSIONS: Although an apparent by rare, Brazilian mammarenavirus infection is an etiology for acute hemorrhagic fever syndrome. The two fatal cases had peculiar histopathological findings not previously described. The virological diagnosis was possible only by contemporary techniques such as metagenomic assays. We found no subsequent infections when we used serological and molecular tests to evaluate close contacts.

Bilateral Wilms' tumor in a child with Denys-Drash syndrome: novel frameshift variant disrupts the WT1 nuclear location signaling region.

OBJECTIVES: Wilm's Tumor (WT) is the most common pediatric kidney cancer. Whereas most WTs are isolated, approximately 5% are associated with syndromes such as Denys-Drash (DDS), characterized by early onset nephropathy, disorders of sex development and predisposition to WT. CASE PRESENTATION: A 46,XY patient presenting with bilateral WT and genital ambiguity without nephropathy was heterozygous for the novel c.851_854dup variant in WT1 gene sequence. This variant affects the protein generating the frameshift p.(Ser285Argfs*14) that disrupts a nuclear localization signal (NLS) region. CONCLUSIONS: This molecular finding is compatible with the severe scenario regarding the Wilm's tumor presented by the patient even though nephropathy was absent.

Chronic exposure to cigarette smoke transiently worsens the disease course in a mouse model of pulmonary paracoccidioidomycosis

ABSTRACT Paracoccidioidomycosis (PCM) may present as an acute/subacute clinical form, characterized by a progressive disease arising from the airborne initial infection, or, most often, as an asymptomatic or subclinical infection that may manifest later during an individual's life, the chronic form. Epidemiological studies show the existence of a strong association between smoking and the development of the chronic form. Current evidence demonstrates that cigarette smoke (CS) has immunosuppressive properties that could be implicated in the increasing susceptibility to the chronic form of PCM. To address this issue, we developed a murine model of a non-progressive pulmonary form of PCM that was exposed to CS at a magnitude that mimicked a moderate smoker. The chronic CS exposure started after 2 weeks and lasted up until 20 weeks post-infection, with the aim of mimicking human natural history, since it is estimated that individuals from endemic areas are infected early in life. The control group consisted of infected but not CS-exposed mice. We assessed the lung fungal burden (colony forming units [CFU]) and the area affected by the granulomatous inflammatory response, fungal dissemination to spleen and liver, and, by immunohistochemistry, the presence of CD4 and CD8 lymphocytes, CD68 and MAC-2 macrophages, and IFN-γ, IL-10 and TNF expressing cells within the granulomatous response. We detected a CS effect as early as 2 weeks after exposure (four weeks post-infection) when the lung CFU of exposed animals was significantly higher than in their non-exposed counterparts. At 12 weeks, the CS-exposed animals presented a more severe disease, as witnessed by the persistent higher lung fungal load (although it did not reach statistical significance [ p = 0.054]), greater dissemination to other organs, greater affected area of the lung, decreased IFN-γ/IL-10 ratio, and higher TNF expression within the granulomas, compared with CS-non-exposed mice. The number of CD4 and CD8 lymphocytes infiltrating the granulomas was similar between both mice groups, but there was a decrease in the number of MAC-2+ macrophages. No difference was noted in the CD68+ macrophage number. However, the follow-up in week 20 showed that the immunological effects of exposure to CS ceased, with both CS and NCS mice showing the same infectious features, i.e., a trend for resolution of the infection. In conclusion, we show that chronic CS-exposure alters the course of the disease in an experimental model of subclinical pulmonary PCM, confirming the epidemiological link between CS-exposure and the chronic form of PCM. However, we also show that this effect is transitory, being detected between 4- and 12-weeks post-infection but not thereafter. The possible immune mechanisms that mediate this effect and the reasons for its transitory effect are discussed.

Autopsy findings in a patient with primary systemic AL (kappa light chain) amyloidosis.

First described by Rokitansky in 1842, and further characterized by Virchow in 1854, amyloidosis is a disorder caused by amyloid deposition, a fibrillary insoluble protein. The clinical spectrum of amyloidosis is broad, as the amyloid deposition may virtually occur in all tissues. Herein, we report the case of a 66-year-old man with a long-lasting emaciating disease, diagnosed, at autopsy, with primary systemic amyloidosis. Amyloid protein deposition was found in many tissues and organs. The involvement of the vessels' wall rendered ischemic injury most prominent in the intestinal loops causing mesenteric ischemia. Despite the thorough organic involvement, the immediate cause of death was aspiration bronchopneumonia. Massive amyloid deposition was found in virtually all major organs, such as the heart, liver, kidneys, spleen, pancreas, adrenals, prostate, skin, and thyroid: the latter, a complication of the amyloidosis known as amyloid goiter. Post-mortem review of the deceased's laboratory workup showed a slightly abnormal kappa:lambda ratio in the blood; however, no clonal lymphoplasmacytic disorder was confirmed in the bone marrow and other lymphoreticular system organs either by the microscopic examination and immunohistochemical staining. Laser-capture microdissection and tandem mass spectrometry of the splenic tissue detected a peptide profile consistent with an immunoglobulin Kappa light chain. The presence of amyloid purpura favors the diagnosis of primary systemic amyloidosis.

Autopsy findings in a patient with primary systemic AL (kappa light chain) amyloidosis

First described by Rokitansky in 1842, and further characterized by Virchow in 1854, amyloidosis is a disorder caused by amyloid deposition, a fibrillary insoluble protein. The clinical spectrum of amyloidosis is broad, as the amyloid deposition may virtually occur in all tissues. Herein, we report the case of a 66-year-old man with a long-lasting emaciating disease, diagnosed, at autopsy, with primary systemic amyloidosis. Amyloid protein deposition was found in many tissues and organs. The involvement of the vessels' wall rendered ischemic injury most prominent in the intestinal loops causing mesenteric ischemia. Despite the thorough organic involvement, the immediate cause of death was aspiration bronchopneumonia. Massive amyloid deposition was found in virtually all major organs, such as the heart, liver, kidneys, spleen, pancreas, adrenals, prostate, skin, and thyroid: the latter, a complication of the amyloidosis known as amyloid goiter. Post-mortem review of the deceased's laboratory workup showed a slightly abnormal kappa:lambda ratio in the blood; however, no clonal lymphoplasmacytic disorder was confirmed in the bone marrow and other lymphoreticular system organs either by the microscopic examination and immunohistochemical staining. Laser-capture microdissection and tandem mass spectrometry of the splenic tissue detected a peptide profile consistent with an immunoglobulin Kappa light chain. The presence of amyloid purpura favors the diagnosis of primary systemic amyloidosis.