Challenges in Diagnosing COVID-19-Associated Pulmonary Aspergillosis in Critically Ill Patients: The Relationship between Case Definitions and Autoptic Data.

Critically ill COVID-19 patients can develop invasive pulmonary aspergillosis (CAPA). Considering the weaknesses of diagnostic tests/case definitions, as well as the results from autoptic studies, there is a debate on the real burden of aspergillosis in COVID-19 patients. We performed a retrospective observational study on mechanically ventilated critically ill COVID-19 patients in an intensive care unit (ICU). The primary objective was to determine the burden of CAPA by comparing clinical diagnosis (through case definitions/diagnostic algorithms) with autopsy results. Twenty patients out of 168 (11.9%) developed probable CAPA. Seven (35%) were females, and the median age was 66 [IQR 59-72] years. Thirteen CAPA patients (65%) died and, for six, an autopsy was performed providing a proven diagnosis in four cases. Histopathology findings suggest a focal pattern, rather than invasive and diffuse fungal disease, in the context of prominent viral pneumonia. In a cohort of mechanically ventilated patients with probable CAPA, by performing a high rate of complete autopsies, invasive aspergillosis was not always proven. It is still not clear whether aspergillosis is the major driver of mortality in patients with CAPA.

Placental pathology in COVID-19 affected pregnant women: A prospective case-control study.

INTRODUCTION: During pregnancy, SARS-CoV-2 infection may cause an abnormal development of the placenta, thus influencing maternal and fetal outcomes. Few studies have reported data on placental morphology and histology in infected pregnant patients, although not compared with carefully matched controls. The aim of this study is to compare placental morphology and histology of pregnant women affected by SARS-CoV-2 to non-infected controls. METHODS: This is a prospective multicenter case-control study on 64 pregnant women affected by SARS-CoV-2 who delivered at term or late-preterm. Data were collected about pregnancy course, maternal and fetal outcomes, placental biometry and macro- and microscopical morphology. 64 not-infected women were identified as controls, matched by age, body mass index and ethnicity. RESULTS: Cases and controls had similar fetal and maternal outcomes. No significant differences were observed in placental macro- or microscopical morphology between the two groups. In the cases treated with antivirals, chloroquine, LMWH or antibiotics, placentas were heavier but not more efficient than the non-treated, since the fetal/placental weight ratio did not differ. Moreover, delayed villous maturation was more frequent in treated women, although not significantly. The newborns whose mothers received oxygen therapy as treatment had higher levels of umbilical cord pO2 at birth. DISCUSSION: In this prospective case-control study, SARS-CoV-2 infection during the third trimester did not influence placental histological pattern. Pharmacological and oxygen therapy administered to women affected by this viral infection could impact maternal and fetal outcomes and be associated to placental histological alterations.

Fungal aneurism of the right posterior inferior cerebellar artery (PICA).

In this case-report, the Authors show the case of a sudden death occurred in a 38-year-old woman submitted to surgical excision of a right acoustic neurinoma. At the autopsy, was detected a cerebral hemorrhage with multifocal localization by a ruptured rare fungal aneurysm of the Posterior Inferior Cerebellar Arthery (PICA). The PCR analysis, carried out on formalin-fixed paraffin-embedded tissue, identified the Aspergillus Penicillioides as the involved pathogen. We discuss the main points of infectious aneurysms, being a potential neurosurgical complication.

5-ALA Fluorescence in Case of Brain Abscess by Aggregatibacter Mimicking Glioblastoma.

BACKGROUND: At present, the differential diagnosis of magnetic resonance imaging enhancing lesions can still be challenging. Preoperative imaging is a valuable tool characterized by high informative value, even if false-positive and false-negative results are possible. In this context, 5-aminolevulenic acid (5-ALA) represents a significant adjunct in glioblastoma (GBM) surgery displaying an assumed specific accumulation only in tumor cells. However, it was anecdotally reported that in some cases it can also be detected in nonneoplastic lesions mimicking GBM, thus potentially leading to misdiagnosis. Moreover, precise identification of involved pathogens from intraoperative brain samples may remain difficult. We report the case of an abscess from Aggregatibacter mimicking a GBM both during preoperative imaging and intraoperatively, since showing 5-ALA fluorescence. CASE DESCRIPTION: A 54-year-old man presented with intense cephalalgia, vomiting, and scotomas in his left eye. Brain magnetic resonance imaging demonstrated a right temporo-occipital rim-enhancing mass, highly suggestive of a GBM, and for this reason the patient underwent 5-ALA-guided complete removal. Histopathologic analysis proved the lesion to be a bacterial abscess from Aggregatibacter as confirmed by polymerase chain reaction on bacterial deoxyribonucleic acid. CONCLUSIONS: 5-ALA fluorescence may not be specifically involved only in malignant tumor cells, thus raising the suspect for alternative diagnoses to GBM and inviting caution into fluorescence-guided surgery.

Gastrointestinal basidiobolomycosis: An emerging mycosis difficult to diagnose but curable. Case report and review of the literature.

BACKGROUND: Gastrointestinal basidiobolomycosis (GIB) is a rare mycosis affecting almost exclusively immunocompetent subjects. METHODS: We describe a case of GIB caused by Basidiobolus ranarum in a 25-year-old Italian immunocompetent man resident in Ireland who presented a 2-month history of epigastric pain. Suspecting colon cancer he underwent a right hemicolectomy subsequently leading to a diagnosis of GIB by means of molecular biology. After surgery a 9-month therapy with itraconazole was employed with a good outcome. A review of medical literature regarding GIB cases published in the period 1964-2017 is presented. RESULTS: One-hundred and two cases of GIB were included in this analysis. The disease was observed predominantly in male gender (74.5%) and children (41.2%). Abdominal pain was the single most common complaint (86.3%) followed by fever (40.2%) and evidence of an abdominal mass (30.4%). Peripheral blood eosinophilia was detected in 85.7% of cases. Most of the patients were diagnosed in Saudi Arabia (37.2%) followed by USA (21.6%) and Iran (20.6%). Surgery plus antifungal therapy was employed in the majority of patients (77.5%). An unfavourable outcome was documented globally in 18.6% of patients. CONCLUSIONS: GIB seems to be an emerging intestinal mycosis among immunocompetent patients living in the Middle East and Arizona.

Diagnosis of Louse-Borne Relapsing Fever despite Negative Microscopy in Two Asylum Seekers from Eastern Africa.

We report two cases of louse-borne relapsing fever observed at our Institution in June 2016. Both patients were young asylum seekers from Africa who had recently arrived in Milan, Italy. Notably, direct microscopic examination of peripheral blood smears was repeatedly negative for the presence of spirochetes and the diagnosis, supported by clinical and epidemiologic evidence, required molecular confirmation by polymerase chain reaction amplification of DNA extracted from blood and sequencing of the amplified products.

Leptin-dependent STAT3 phosphorylation in postnatal mouse hypothalamus.

Leptin, a hormone produced by adipose tissue, reduces food intake and boosts energy expenditure via activation of the JAK2-STAT3 signalling pathway in adult mammal hypothalamic neurons. It is found in blood early after birth, peaking around postnatal day (P) 10. The hypothalamus of neonatal mice administered intraperitoneal leptin (3 mg/kg of body weight) was investigated for phospho-STAT3-positive cells to gain insights into the timing of maturation of the leptin signal transduction system. Leptin responsiveness was first detected in arcuate nucleus, where it was faint at P1 and evident from P5. It was then identified in medial preoptic area, anterior hypothalamus, retrochiasmatic area, dorsomedial nucleus and premammillary nucleus from P7, and in ventromedial nucleus and lateral hypothalamus from P11. From P13 onwards, hypothalamic P-STAT3 staining was indistinguishable from that of adult mice. Significant hypothalamic STAT3 activation was also detected by Western blotting at P11 and P15. The level of activation seen in adults was comparable to that observed at P15 although, remarkably, leptin-induced feeding reduction is observed only after the fourth postnatal week. Neuronal and glial markers and double-labelling immunohistochemistry showed that leptin-stimulated hypothalamic cells that had already reached their final position in a given area or nucleus were neurons; however, leptin responsiveness preceded positivity for the neuronal markers, suggesting a not fully differentiated status. Interestingly, leptin also increased P-STAT3 and c-Fos immunoreactivity in a distinctive and transient (from P5 to P13) cell population found in the dorsal part of the third ventricle and in subependymal position. These cells did not express mature or immature neuronal or glial markers. Their ultrastructural appearance, though suggestive of differentiating cells, was not conclusive for a specific phenotype.

Leptin increases axonal growth cone size in developing mouse cortical neurons by convergent signals inactivating glycogen synthase kinase-3beta.

We examined the effects of the adipose hormone leptin on the development of mouse cortical neurons. Treatment of neonatal and adult mice with intraperitoneal leptin (5 mg/kg) induced extracellular signal-regulated kinase (ERK) 1/2 phosphorylation in pyriform and entorhinal cortex neurons. Stimulation of cultured embryonic cortical neurons with leptin evoked Janus kinase 2 and ERK1/2 phosphorylation and activated the downstream effector 90-kDa ribosomal protein S6 kinase. Moreover, leptin elicited the phosphorylation of the phosphatidylinositol 3-kinase effector Akt and evoked Ser-9 phosphorylation of glycogen synthase kinase-3beta (GSK3beta), an event inactivating this kinase. Leptin-mediated GSK3beta phosphorylation was prevented by the MEK/ERK inhibitor PD98059, the phosphatidylinositol 3-kinase inhibitor LY294002, or the protein kinase C inhibitor GF109203X. Exposure of cortical neurons to leptin also induced Ser-41 phosphorylation of the neuronal growth-associated protein GAP-43, an effect prevented by LY294002 and GF109203X but not by PD98059. Ser-41-GAP-43 phosphorylation is usually high in expanding axonal growth cones. Neurons exposed to 100 ng/ml leptin for 72 h displayed reduced rate of growth cone collapse, a shift of growth cone size distribution toward higher values, and a 4-fold increase in mean growth cone surface area compared with control cultures. The leptin-induced growth cone spreading was hampered in cortical neurons from Lepr(db/db) mice lacking functional leptin receptors; it was associated with localized Ser-9-GSK3beta phosphorylation and mimicked by the GSK3beta inhibitor SB216763. At concentrations preventing GSK3beta phosphorylation, PD98059, LY294002, or GF109203X reversed the leptin-induced growth cone surface enlargement. We concluded that the leptin-mediated regulation of growth cone morphogenesis in cortical neurons relies on upstream regulators of GSK3beta activity.

The hydrolipidic ratio in age-related maturation of adipose tissues.

The hydrolipidic ratio (HLR) expresses the amount of water and fat in a tissue. HLR can be studied non-invasively in the living organism and can be mapped in different areas of the body with high spatial and temporal resolution. In the present work we have evaluated the HLR in different adipose tissue depots in young or adult rats using tissue arrays of fat fragments by 1H-spectroscopy. In young animals, the highest percentage of water (33%) was found in the interscapular brown adipose tissue (iBAT). Mesenteric fat (mWAT) also appeared highly hydrated (24%). The deposits composed of epididymal, retroperitoneal and pelvic white adipose tissue (eWAT, rWAT and pWAT, respectively) contained an amount of water ranging from 14% to 17%. In adult animals, a reduction of the water content was found in all the depots. In e/r/pWAT, the age-related maturation was characterized by large changes in adipocyte diameter accompanied by a small change in HLR. In the iBAT, the maturation was accompanied by small change in adipocyte diameter and a greater diminution of HLR. mWAT showed an intermediate pattern between e/r/pWAT and iBAT. In all the studied depots, an age-related increase in leptin expression was found. This increase was relatively low in iBAT (40%) and high in the e/r/pWAT (204-273%). The work expand the knowledge about the physiological significance of the HLR by 1H-spectroscopy.

Calorie restriction promotes mitochondrial biogenesis by inducing the expression of eNOS.

Calorie restriction extends life span in organisms ranging from yeast to mammals. Here, we report that calorie restriction for either 3 or 12 months induced endothelial nitric oxide synthase (eNOS) expression and 3',5'-cyclic guanosine monophosphate formation in various tissues of male mice. This was accompanied by mitochondrial biogenesis, with increased oxygen consumption and adenosine triphosphate production, and an enhanced expression of sirtuin 1. These effects were strongly attenuated in eNOS null-mutant mice. Thus, nitric oxide plays a fundamental role in the processes induced by calorie restriction and may be involved in the extension of life span in mammals.

Regional-dependent increase of sympathetic innervation in rat white adipose tissue during prolonged fasting.

White adipose tissue (WAT) is innervated by the sympathetic nervous system. A role for WAT sympathetic noradrenergic nerves in lipid mobilization has been suggested. To gain insight into the involvement of nerve activity in the delipidation process, WAT nerves were investigated in rat retroperitoneal and epididymal depots after prolonged fasting. A significant increase in tyrosine hydroxylase (TH) content was found in epididymal and, especially, retroperitoneal WAT by Western blotting. Accordingly, an increased immunoreactivity for TH was detected by immunohistochemistry in epididymal and, especially, retroperitoneal vascular and parenchymal noradrenergic nerves. Neuropeptide Y (NPY)-containing nerves were found around arteries and in the parenchyma. Double-staining experiments and confocal microscopy showed that most perivascular and some parenchymal noradrenergic nerves also contained NPY. Detection of protein gene product (PGP) 9.5, a general marker of peripheral nerves, by Western blotting and PGP 9.5-TH by double-staining experiments showed significantly increased noradrenergic nerve density in fasted retroperitoneal, but not epididymal depots, suggesting that formation of new nerves takes place in retroperitoneal WAT in fasting conditions. On the whole, these data confirm the important role of sympathetic noradrenergic nerves in WAT lipid mobilization during fasting but also raise questions about the physiological role of regional-dependent nerve adjustments and their functional significance in relation to white adipocyte secretory products.

Reversible transdifferentiation of secretory epithelial cells into adipocytes in the mammary gland.

Mammalian breast adipose tissue is replaced by a milk-secreting gland during pregnancy; the reverse process takes place upon interruption of lactation. Morphological and bromodeoxyuridine studies provide indirect evidence that mouse mammary adipocytes transform into secretory epithelial cells during pregnancy and revert to adipocytes after lactation. By using the Cre-loxP recombination system we show that the mammary gland of whey acidic protein (WAP)-Cre/R26R mice, in which secretory epithelial cells express the lacZ gene during pregnancy, contains labeled adipocytes during involution. Conversely, adipocyte P2-Cre/R26R mice, in which adipocytes are labeled before pregnancy, contain labeled secretory epithelial cells during pregnancy. We conclude that reversible adipocyte-to-epithelium and epithelium-to-adipocyte transdifferentiation occurs in the mammary gland of adult mice during pregnancy and lactation.

Mitochondrial biogenesis by NO yields functionally active mitochondria in mammals.

We recently found that long-term exposure to nitric oxide (NO) triggers mitochondrial biogenesis in mammalian cells and tissues by activation of guanylate cyclase and generation of cGMP. Here, we report that the NO/cGMP-dependent mitochondrial biogenesis is associated with enhanced coupled respiration and content of ATP in U937, L6, and PC12 cells. The observed increase in ATP content depended entirely on oxidative phosphorylation, because ATP formation by glycolysis was unchanged. Brain, kidney, liver, heart, and gastrocnemius muscle from endothelial NO synthase null mutant mice displayed markedly reduced mitochondrial content associated with significantly lower oxygen consumption and ATP content. In these tissues, ultrastructural analyses revealed significantly smaller mitochondria. Furthermore, a significant reduction in the number of mitochondria was observed in the subsarcolemmal region of the gastrocnemius muscle. We conclude that NO/cGMP stimulates mitochondrial biogenesis, both in vitro and in vivo, and that this stimulation is associated with increased mitochondrial function, resulting in enhanced formation of ATP.

Can endogenous gaseous messengers control mitochondrial biogenesis in mammalian cells?

Mitochondria have been identified as the site of oxidative energy metabolism and of numerous biosynthetic and degradative reactions, which depend on a distinctive mitochondrial structure, with different enzymes and reactions localised in discrete membranes and aqueous compartments. Synthesis and import of mitochondrial components are required for mitochondrial proliferation, but rather than producing new organelles, these processes may facilitate the growth of preexisting mitochondria. Recent evidence indicates that these events are regulated in a complex way by several agonists and environmental conditions, through activation of specific transcription factors and signaling pathways. Some of these are now being elucidated. Generation of nitric oxide (NO) appears to be a novel player in this scenario, possibly acting as a unifying molecular switch to trigger the whole process of the mitochondrial biogenesis.

Role of insulin and free fatty acids in the regulation of ob gene expression and plasma leptin in normal rats.

OBJECTIVE: It is under debate whether free fatty acids (FFAs) play an independent role in the regulation of adipose cell functions. In this study, we evaluated whether leptin secretion induced by FFA is due directly to an increased FFA availability or whether it is mediated by insulin levels. RESEARCH METHODS AND PROCEDURES: To test this hypothesis, we compared the effects of six different experimental designs, with different FFA and insulin levels, on plasma leptin: euglycemic clamp, euglycemic clamp + FFA infusion, FFA infusion alone, FFA + somatostatin infusion, somatostatin infusion alone, and saline infusion. RESULTS: Our results showed that euglycemic clamp, FFA infusion, or both in combination induced a similar increment of circulating leptin (3.31 +/- 0.30, 3.40 +/- 0.90, and 3.35 +/- 0.80 ng/mL, respectively). Moreover, the inhibition of FFA-induced insulin increase by means of somatostatin infusion completely abolished the rise of leptin in response to FFA (1.05 +/- 0.30 vs. 3.40 +/- 0.90 ng/mL, p < 0.001). DISCUSSION: In conclusion, our data showed that the effects of high FFA levels on plasma leptin were mediated by the rise of insulin concentration. These data confirm a major role for insulin in the regulation of leptin secretion from rat adipose tissue and support the hypothesis that leptin secretion is coupled to net triglyceride synthesis in adipose tissue.

Mitochondrial biogenesis in mammals: the role of endogenous nitric oxide.

Nitric oxide was found to trigger mitochondrial biogenesis in cells as diverse as brown adipocytes and 3T3-L1, U937, and HeLa cells. This effect of nitric oxide was dependent on guanosine 3',5'-monophosphate (cGMP) and was mediated by the induction of peroxisome proliferator-activated receptor gamma coactivator 1alpha, a master regulator of mitochondrial biogenesis. Moreover, the mitochondrial biogenesis induced by exposure to cold was markedly reduced in brown adipose tissue of endothelial nitric oxide synthase null-mutant (eNOS-/-) mice, which had a reduced metabolic rate and accelerated weight gain as compared to wild-type mice. Thus, a nitric oxide-cGMP-dependent pathway controls mitochondrial biogenesis and body energy balance.