Case report: Thirty-year progression of an EMPF1 encephalopathy due to defective mitochondrial and peroxisomal fission caused by a novel de novo heterozygous DNM1L variant.

Mutations in DNM1L (DRP1), which encode a key player of mitochondrial and peroxisomal fission, have been reported in patients with the variable phenotypic spectrum, ranging from non-syndromic optic atrophy to lethal infantile encephalopathy. Here, we report a case of an adult female patient presenting with a complex neurological phenotype that associates axonal sensory neuropathy, spasticity, optic atrophy, dysarthria, dysphasia, dystonia, and ataxia, worsening with aging. Whole-exome sequencing revealed a heterozygous de novo variant in the GTPase domain of DNM1L [NM_001278464.1: c.176C>A p.(Thr59Asn)] making her the oldest patient suffering from encephalopathy due to defective mitochondrial and peroxisomal fission-1. In silico analysis suggested a protein destabilization effect of the variant Thr59Asn. Unexpectedly, Western blotting disclosed profound decrease of DNM1L expression, probably related to the degradation of DNM1L complexes. A detailed description of mitochondrial and peroxisomal anomalies in transmission electron and 3D fluorescence microscopy studies confirmed the exceptional phenotype of this patient.

Clinical course and challenging management of early COVID-19 infection after heart transplantation: case report of two patients.

BACKGROUND: There are limited data on Coronavirus disease 2019 (COVID-19) in solid organ transplant patients, especially in heart transplant recipients, with only a few case reports and case series described so far. Heart transplant recipients may be at particular high risk due to their comorbidities and immunosuppressed state. CASE PRESENTATION: This report describes the clinical course and the challenging management of early COVID-19 infection in two heart transplant recipients who tested positive for the SARS-CoV-2 virus in the perioperative period of the transplant procedure. The two patients developed a severe form of the disease and ultimately died despite the initiation of an antiviral monotherapy with hydroxychloroquine coupled with the interruption of mycophenolate mofetil. CONCLUSIONS: These two cases illustrate the severity and poor prognosis of COVID-19 in the perioperative period of a heart transplant. Thorough screening of donors and recipients is mandatory, and the issue of asymptomatic carriers needs to be addressed.

COVID-19-associated Nephropathy Includes Tubular Necrosis and Capillary Congestion, with Evidence of SARS-CoV-2 in the Nephron.

Background: Kidney damage has been reported in patients with COVID-19. Despite numerous reports about COVID-19-associated nephropathy, the factual presence of the SARS-CoV-2 in the renal parenchyma remains controversial. Methods: We consecutively performed 16 immediate (≤3 hours) postmortem renal biopsies in patients diagnosed with COVID-19. Kidney samples from five patients who died from sepsis not related to COVID-19 were used as controls. Samples were methodically evaluated by three pathologists. Virus detection in the renal parenchyma was performed in all samples by bulk RNA RT-PCR (E and N1/N2 genes), immunostaining (2019-nCOV N-Protein), fluorescence in situ hybridization (nCoV2019-S), and electron microscopy. Results: The mean age of our COVID-19 cohort was 68.2±12.8 years, most of whom were male (69%). Proteinuria was observed in 53% of patients, whereas AKI occurred in 60% of patients. Acute tubular necrosis of variable severity was found in all patients, with no tubular or interstitial inflammation. There was no difference in acute tubular necrosis severity between the patients with COVID-19 versus controls. Congestion in glomerular and peritubular capillaries was respectively observed in 56% and 88% of patients with COVID-19, compared with 20% of controls, with no evidence of thrombi. The 2019-nCOV N-Protein was detected in proximal tubules and at the basolateral pole of scattered cells of the distal tubules in nine out of 16 patients. In situ hybridization confirmed these findings in six out of 16 patients. RT-PCR of kidney total RNA detected SARS-CoV-2 E and N1/N2 genes in one patient. Electron microscopy did not show typical viral inclusions. Conclusions: Our immediate postmortem kidney samples from patients with COVID-19 highlight a congestive pattern of AKI, with no significant glomerular or interstitial inflammation. Immunostaining and in situ hybridization suggest SARS-CoV-2 is present in various segments of the nephron.

Sudden cardiogenic shock mimicking fulminant myocarditis in a surviving teenager affected by severe acute respiratory syndrome coronavirus 2 infection.

In the context of the coronavirus disease 2019 pandemic, myocardial injury is a relatively frequent finding. Progression to cardiogenic shock has been rarely described, especially in healthy young patients. The underlying mechanisms are to date controversial. A previously healthy 18-year-old female teenager affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) developed fulminant cardiogenic shock requiring a prompt extracorporeal membrane oxygenation support. Cardiac involvement was predominant compared with the pulmonary one. Myocardial biopsies were performed; and in order to clarify the pathophysiology of the acute heart failure, optical and transmission electron microscopy study was realized. Two additional immunohistology techniques were developed in order to (i) detect a SARS-CoV-2 recombinant fusion nucleoprotein by using a specific antibody and (ii) study fractalkine expression induced by activated endothelium because this molecule is well known to be elevated in patients with severe cytokine release syndrome. SARS-CoV-2 genome was not detected in the myocardium. Even if the clinical presentation, laboratory markers, and cardiac imaging techniques strongly suggested fulminant myocarditis, histology and immunohistology were not fully consistent with this diagnosis according to the Dallas criteria. Although rare suspected coronavirus particles were found by transmission electron microscopy in the cardiac endothelium, neither significant immunoreactivity for the viral nucleocapsid protein nor image suggestive of endotheliitis was detected. Intense endothelial immunoreactivity pattern for fractalkine expression was observed. From a clinical point of view, the left ventricular systolic function gradually improved, and the patient survived after a long stay in the intensive care unit. Our observations suggest that a massive cytokine storm induced by SARS-CoV-2 infection was the main cause of the cardiogenic shock, making a direct viral injury pathway very unlikely.

Bi-allelic AEBP1 mutations in two patients with Ehlers-Danlos syndrome.

The Ehlers-Danlos syndromes (EDSs) are a clinically and molecularly diverse group of heritable connective tissue disorders caused by defects in a wide range of genes. Recently, bi-allelic loss-of-function mutations in the adipocyte enhancer-binding protein 1 (AEBP1) gene were reported in three families with an autosomal recessive EDS-like condition characterized by thin and hyperextensible skin, poor wound healing with prominent atrophic scarring, joint hypermobility and osteoporosis. Using whole exome sequencing, we identified novel bi-allelic AEBP1 variants in two unrelated adult patients, previously diagnosed with an undefined EDS type, which shows important clinical resemblance to several other EDS subtypes. Our patients present with similar cutaneous and musculoskeletal features as the previously reported patients. They also show unreported clinical features, including pectus deformity, premature aged appearance, sparse and frizzled hair, fatigue and pain. AEBP1 is ubiquitously expressed and encodes the secreted aortic carboxypeptidase-like protein (ACLP) that can bind fibrillar collagens and assist in collagen polymerization. Transmission electron microscopy studies on the patients' skin biopsies show ultrastructural alterations in collagen fibril diameter and appearance, underscoring an important role for ACLP in collagen fibril organization. This report further expands the clinical, molecular and ultrastructural spectrum associated with AEBP1 defects and highlights the complex and variable phenotype associated with this new EDS variant.

Tumor ZAC1 expression is associated with the response to somatostatin analog therapy in patients with acromegaly.

Somatostatin analogs (SSA) with their potent antisecretory and antiproliferative effects are the main medical treatment option for patients with neuroendocrine tumors, such as gastroenteropancreatic and acromegaly-associated growth hormone secreting pituitary tumors. Although a good portion of acromegalic patients gets normalized after SSA treatment, strict hormonal control is not achieved in a sizeable proportion of these patients. The reasons for this incomplete response to SSA treatment are unclear. We have found that the tumor suppressor ZAC1 (LOT1/PLAGL1) is essential for the antiproliferative effect of SSA in pituitary tumor cells. The aim of the present retrospective cohort study was to determine whether ZAC1 immunoreactivity in archival somatotrophinoma tissue derived from 45 patients with acromegaly routinely pretreated with SSA before surgery, was associated with response to SSA (normalization of GH, IGF-I and presence of tumor shrinkage). All tumors displayed ZAC1 immunoreactivity [weak (+; n = 15), moderate (++; n = 16) and strong (+++; n = 14)]. A significant positive correlation was found between strong ZAC1 immunoreactivity and IGF-I normalization and presence of tumor shrinkage after SSA treatment, which was not affected by age at diagnosis, gender or duration of SSA treatment. These in vivo data combined with the antiproliferative properties of ZAC1/Zac1 provide evidence of a mechanistic role for this transcription factor on SSA induced tumor shrinkage and hormone normalization.

Immunoquantitative PCR for prion protein detection in sporadic Creutzfeldt-Jakob disease.

BACKGROUND: The most common human prion disorder is Creutzfeldt-Jakob disease (CJD); it includes sporadic, familial, iatrogenic, and variant subtypes. Diagnostic tests aim at detection with the highest specificity of very small deposits of abnormal prion protein (PrP). METHODS: We used immunoquantitative PCR (iqPCR) to detect proteinase K-resistant PrP (PrPRes) in tissue from the middle frontal gyrus of 7 patients with sporadic CJD and 7 non-CJD cases. We compared iqPCR with routine optimized ELISA, Western blotting, and immunohistochemical analyses. RESULTS: The 4 methods showed similar 100% sensitivity and specificity for the diagnosis of CJD. Along with high specificity, however, iqPCR had a threshold for PrP(Res) detection at least 10-fold lower than that of the classic ELISA. CONCLUSIONS: iqPCR is a new method for PrPRes detection that combines 100% specificity with a detection threshold at least 10-fold lower than classic techniques. This method may improve the detection of minute PrPRes deposits in tissues and body fluids and thus be useful for diagnostic and sterilization applications.

Vascular endothelial growth factor expression correlates with matrix metalloproteinases MT1-MMP, MMP-2 and MMP-9 in human glioblastomas.

Vascular endothelial growth factor (VEGF) is the major endothelial mitogen in central nervous system neoplasms and it is expressed in 64-95% of glioblastomas (GBMs). Tumour cells are the main source of VEGF in GBMs whereas VEGF receptors (VEGFR-1, its soluble form sVEGFR-1, VEGFR-2 and neuropilin-1) are expressed predominantly by endothelial cells. Infiltrating tumour cells and newly-formed capillaries progress through the extracellular matrix by local proteolysis involving matrix metalloproteinases (MMPs). Recent studies have shown that VEGF expression and bioavailability can be modulated by MMPs. We reported previously that the expression of MT1-MMP in human breast cancer cells was associated with an enhanced VEGF expression. We used quantitative RT-PCR, Western blot, gelatin zymography and immunohistochemistry to study the expression of VEGF, VEGFR-1, VEGFR-2, sVEGFR-1, neuropilin-1, MT1-MMP, MMP-2, MMP-9 and TIMP-2 in 20 human GBMs and 5 normal brains. The expression of these MMPs was markedly increased in most GBMs with excellent correlation between mRNA and protein levels; activated forms of MMP-2 and MMP-9 were present in 8/18 and 7/18 of GBMs. A majority of GBMs (17/20) also expressed high levels of VEGF, as previously reported, with strong correlation between VEGF and MT1-MMP gene expression levels, and double immunostaining showed that VEGF and MT1-MMP peptides co-localize in tumour and endothelial cells. Our results suggest that the interplay between metalloproteinases and VEGF previously described in experimental tumours may also be operative in human GBMs. Because of its dual ability to activate MMP-2 and to up-regulate VEGF, MT1-MMP might be of central importance in the growth of GBMs and represent an interesting target for anti-cancer treatments.