Practical implications of the 2019 Nobel Prize in Physiology or Medicine: from molecular adaptation to hypoxia to novel anti-anemic drugs in the clinic

The 2019 Nobel Prize for Medicine or Physiology was assigned to three prestigious physician-scientists, Gregg L. Semenza, William G. Kaelin, and Peter J. Ratcliffe, who clarified the molecular mechanisms of hypoxia adaptation. This viewpoint traces their fundamental findings, which have paved the way for the development of innovative drugs for a wide range of common diseases, including cancer and anemia.

Fatal respiratory infection due to ST308 VIM-1-producing Pseudomonas aeruginosa in a lung transplant recipient: case report and review of the literature

Background

Data regarding the prevalence of metallo-β-lactamases (MBLs) among Pseudomonas aeruginosa isolates in cystic fibrosis patients are scarce. Furthermore, there is limited knowledge on the effect of MBL production on patient outcomes. Here we describe a fatal respiratory infection due to P. aeruginosa producing VIM-type MBLs in a lung transplant recipient and the results of the subsequent epidemiological investigation.

Case presentation

P. aeruginosa isolates collected in the index patient and among patients temporally or spatially linked with the index patient were analyzed in terms of antibiotic susceptibility profile and MBL production. Whole-genome sequencing and phylogenetic reconstruction were also performed for all P. aeruginosa isolates producing VIM-type MBLs. A VIM-producing P. aeruginosa strain was identified in a lung biopsy of a lung transplant recipient with cystic fibrosis. The strain was VIM-1-producer and belonged to the ST308. Despite aggressive treatment, the transplant patient succumbed to the pulmonary infection due to the ST308 strain. A VIM-producing P. aeruginosa strain was also collected from the respiratory samples of a different cystic fibrosis patient attending the same cystic fibrosis center. This isolate harbored the blaVIM-2 gene and belonged to the clone ST175. This patient did not experience an adverse outcome.

Conclusions

This is the first description of a fatal infection due to P. aeruginosa producing VIM-type MBLs in a lung transplant recipient. The circulation of P. aeruginosa isolates harboring MBLs pose a substantial risk to the cystic fibrosis population due to the limited therapeutic options available and their spreading potential.

Deep vein thrombosis in SARS-CoV-2 pneumonia-affected patients within standard care units: Exploring a submerged portion of the iceberg

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An association between COVID-19 and venous thromboembolism (VTE) is now recognized.

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The prevalence of VTE is high in COVID-19 patients hospitalized in standard care units.

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The prevalence of VTE is high even though thromboprophylaxis and in patients estimated at low risk.

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A high index of suspicion for VTE is crucial in patients with SARS-CoV-2 infection.

Pneumonic versus Nonpneumonic Exacerbations of Chronic Obstructive Pulmonary Disease

Patients with chronic obstructive pulmonary disease (COPD) often suffer acute exacerbations (AECOPD) and community-acquired pneumonia (CAP), named nonpneumonic and pneumonic exacerbations of COPD, respectively. Abnormal host defense mechanisms may play a role in the specificity of the systemic inflammatory response. Given the association of this aspect to some biomarkers at admission (e.g., C-reactive protein), it can be used to help to discriminate AECOPD and CAP, especially in cases with doubtful infiltrates and advanced lung impairment. Fever, sputum purulence, chills, and pleuritic pain are typical clinical features of CAP in a patient with COPD, whereas isolated dyspnea at admission has been reported to predict AECOPD. Although CAP may have a worse outcome in terms of mortality (in hospital and short term), length of hospitalization, and early readmission rates, this has only been confirmed in a few prospective studies. There is a lack of methodologically sound research confirming the impact of severe AECOPD and COPD + CAP. Here, we review studies reporting head-to-head comparisons between AECOPD and CAP + COPD in hospitalized patients. We focus on the epidemiology, risk factors, systemic inflammatory response, clinical and microbiological characteristics, outcomes, and treatment approaches. Finally, we briefly discuss some proposals on how we should orient research in the future.

Oxidative stress biomarkers in Fabry disease: is there a room for them?

BACKGROUND

Fabry disease (FD) is an X-linked lysosomal storage disorder, caused by deficient activity of the alpha-galactosidase A enzyme leading to progressive and multisystemic accumulation of globotriaosylceramide. Recent data point toward oxidative stress signalling which could play an important role in both pathophysiology and disease progression.

METHODS

We have examined oxidative stress biomarkers [Advanced Oxidation Protein Products (AOPP), Ferric Reducing Antioxidant Power (FRAP), thiolic groups] in blood samples from 60 patients and 77 healthy controls.

RESULTS

AOPP levels were higher in patients than in controls (p < 0.00001) and patients presented decreased levels of antioxidant defences (FRAP and thiols) with respect to controls (p < 0.00001). In a small group of eight treatment-naïve subjects with FD-related mutations, we found altered levels of oxidative stress parameters and incipient signs of organ damage despite normal lyso-Gb3 levels.

CONCLUSIONS

Oxidative stress occurs in FD in both treated and naïve patients, highlighting the need of further research in oxidative stress-targeted therapies. Furthermore, we found that oxidative stress biomarkers may represent early markers of disease in treatment-naïve patients with a potential role in helping interpretation of FD-related mutations and time to treatment decision.

Genetic and Clinical Heterogeneity in Thirteen New Cases with Aceruloplasminemia. Atypical Anemia as a Clue for an Early Diagnosis

Aceruloplasminemia is a rare autosomal recessive genetic disease characterized by mild microcytic anemia, diabetes, retinopathy, liver disease, and progressive neurological symptoms due to iron accumulation in pancreas, retina, liver, and brain. The disease is caused by mutations in the Ceruloplasmin (CP) gene that produce a strong reduction or absence of ceruloplasmin ferroxidase activity, leading to an impairment of iron metabolism. Most patients described so far are from Japan. Prompt diagnosis and therapy are crucial to prevent neurological complications since, once established, they are usually irreversible. Here, we describe the largest series of non-Japanese patients with aceruloplasminemia published so far, including 13 individuals from 11 families carrying 13 mutations in the CP gene (7 missense, 3 frameshifts, and 3 splicing mutations), 10 of which are novel. All missense mutations were studied by computational modeling. Clinical manifestations were heterogeneous, but anemia, often but not necessarily microcytic, was frequently the earliest one. This study confirms the clinical and genetic heterogeneity of aceruloplasminemia, a disease expected to be increasingly diagnosed in the Next-Generation Sequencing (NGS) era. Unexplained anemia with low transferrin saturation and high ferritin levels without inflammation should prompt the suspicion of aceruloplasminemia, which can be easily confirmed by low serum ceruloplasmin levels. Collaborative joint efforts are needed to better understand the pathophysiology of this potentially disabling disease.

A Five-Step Vascular Ultrasound Examination in Heart Failure: The First Two Years of the "ABCDE" G-SIUMB Multicenter Study 2018-2022

The aim of this study is the creation of a 5-step ultrasound examination to evaluate and monitor Heart Failure (HF) patients during hospitalization and follow-up. "ABCDE" is the acronym of an Italian multicentre study composed of a consecutive sample of HF patients admitted from the Emergency to the Internal Medicine/Geriatric Departments of several Italian hospitals. The "ABCDE" score includes the evaluations of A, the Ankle-brachial index (ABI), B, the B-lines, C, the Carotid intima media thickness (CIMT), D, the Diameter of the abdominal aorta and of the inferior cave vein and E, the echocardiographic assessment of the ejection fraction. This paper reports the preliminary results. Up to now, the "ABCDE" multicenter study seems an exciting opportunity to create an integrative ultrasound approach in HF. The definitive confirmation of these preliminary results and the effective usefulness of the "ABCDE" will be available in 2022, at the end of the study.

Red Blood Cell Susceptibility to Lipid Peroxidation, Membrane Lipid Composition, and Antioxidant Enzymes in Continuous Ambulatory Peritoneal Dialysis Patients

Objective

To investigate the overall susceptibility of red blood cells (RBC) to lipid peroxidation from patients on continuous ambulatory peritoneal dialysis (CAPD).

Methods

The following parameters were measured: RBC malondialdehyde (MDA) production after oxidative stress with H2O2, RBC antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), and RBC membrane lipid composition. The levels of plasma vitamin E and serum selenium were also as sayed.

Patients

Eleven patients on continuous ambulatory peritoneal dialysis. Twenty-one healthy blood donors of similar age were used as normal controls.

Results

The MDA formation after H2O2 stimulation was normal in CAPD patients (0.79±0.1 μmol/gHb versus 0.78±0.1 in the control group). RBC from CAPD patients also showed a normal SOD activity, a more than adequate vitamin E status, and a peculiar pattern of membrane lipids, with reduced polyunsaturated fatty acids (p<0.001) and increased monounsaturated fatty acids (p<0.001). Both RBC GSH-Px activity, a selenium-dependent enzyme, and serum selenium levels were significantly lower in CAPD patients, and a significant positive correlation (r=0.68; p<0.02) between the two parameters was found.

Conclusions

This study found a normal sensitivity to oxidant stress in RBC from a group of CAPD patients, despite an impaired GSH-Px activity. The peculiar lipid pattern of RBC membrane, characterized by reduced PUFA and increased MUFA content, may contribute, in addition to adequate SOD activity and vitamin E status, to normal RBC lipid peroxidation.

Pentosan polysulfate to control hepcidin expression in vitro and in vivo

Hepcidin peptide is crucial in the regulation of systemic iron availability controlling its uptake from the diet and its release from the body storage tissues. Hepcidin dysregulation causes different human disorders ranging from iron overload (e.g. hemochromatosis) to iron deficiency (e.g. anemia). Hepcidin excess is common in the Anemia of Chronic Diseases or Anemia of Inflammation and in the genetic form of anemia named IRIDA; the pharmacological downregulation of hepcidin in these disorders could improve the anemia. Commercial heparins were shown to be strong inhibitors of hepcidin expression, by interfering with BMP6/SMAD pathway. The non-anti-coagulant heparins, modified to abolish the anti-thrombin binding site, were equally potent and could be used to improve iron status. To perform its anti-hepcidin activity heparin needs 2O- and 6O-sulfation and an average molecular weight (MW) up to 4000-8000 Dalton, depending on the sulfation level. The pentosane polysulfate (PPS), which shares with heparin a high degree of sulfation, is a compound with low anti-coagulant activity that is already in use for pharmaceutical treatment. In the present work we analyzed the anti-hepcidin activity of PPS in vitro and in vivo. We found that it acts as a strong inhibitor of hepcidin expression in HepG2 cells with an effect already visible after 2-3 h of treatment. It also suppressed hepcidin in mice in a dose dependent manner after 3 h and with a significant redistribution of systemic iron without evident side effects. PPS is also able to abolish the LPS dependent hepcidin upregulation similarly to that showed for heparin derivatives. These results suggest PPS as an interesting compound to control hepcidin in vivo.

Gain-of-function mutations in PIEZO1 directly impair hepatic iron metabolism via the inhibition of the BMP/SMADs pathway

Dehydrated hereditary stomatocytosis (DHS), or xerocytosis, is an autosomal dominant hemolytic anemia. Most patients with DHS carry mutations in the PIEZO1 gene encoding a mechanosensitive cation channel. We here demonstrate that patients with DHS have low levels of hepcidin and only a slight increase of ERFE, the erythroid negative regulator of hepcidin. We demonstrated that at the physiological level, PIEZO1 activation induced Ca²⁺ influx and suppression of HAMP expression in primary hepatocytes. In two hepatic cellular models expressing PIEZO1 WT and two PIEZO1 gain-of-function mutants (R2456H and R2488Q), we highlight altered expression of a few genes/proteins involved in iron metabolism. Mutant cells showed increased intracellular Ca²⁺ compared to WT, which was correlated to increased phosphorylation of ERK1/2, inhibition of the BMP-SMADs pathway, and suppression of HAMP transcription. Moreover, the HuH7 cells, treated with PD0325901, a potent inhibitor of ERK1/2 phosphorylation, reduced the phosphorylation of ERK1/2 with the consequent increased phosphorylation of SMAD1/5/8, confirming the link between the two pathways. Another "proof of concept" for the mechanism that links PIEZO1 to HAMP regulation was obtained by mimicking PIEZO1 activation by cell Ca²⁺ overload, by the Ca²⁺ ionophore A23187. There was strong down-regulation of HAMP gene expression after this Ca²⁺ overload. Finally, the inhibition of PIEZO1 by GsMTx4 leads to phenotype rescue. This is the first demonstration of a direct link between PIEZO1 and iron metabolism, which defines the channel as a new hepatic iron metabolism regulator and as a possible therapeutic target of iron overload in DHS and other iron-loading anemias.

Impact of natural neuromedin-B receptor variants on iron metabolism

Iron overload heritability remains partly unexplained. By performing whole exome sequencing in three patients with a clinical phenotype of hemochromatosis not accounted by known genetic risk factors, we identified in all patients rare variants predicted to alter activity of Neuromedin-B receptor (NMBR). Coding NMBR mutations were enriched in 129 patients with hereditary hemochromatosis or iron overload phenotype, as compared to ethnically matched controls, including 100 local healthy blood donors and 1000Genomes project participants (15.5% vs 5%, P = .0038 at burden test), and were associated with higher transferrin saturation in regular blood donors (P = .04). Consistently, in 191 patients with nonalcoholic fatty liver, the most common low-frequency p.L390 M variant was independently associated with higher ferritin (P = .03). In 58 individuals, who underwent oral iron challenge, carriage of the p.L390 M variant was associated with higher transferrin saturation and lower hepcidin release. Furthermore, the circulating concentration of the natural NMBR ligand, Neuromedin-B, was reduced in response to iron challenge. It was also decreased in individuals carrying the p.L390 M variant and with hemochromatosis in parallel with increased transferrin saturation. In mice, Nmbr was induced by chronic dietary iron overload in the liver, gut, pancreas, spleen, and skeletal muscle, while Nmb was downregulated in gut, pancreas and spleen. Finally, Nmb amplified holo-transferrin dependent induction of hepcidin in primary mouse hepatocytes, which was associated with Jak2 induction and abolished by the NMBR antagonist PD168368. In conclusion, NMBR natural variants were enriched in patients with iron overload, and associated with facilitated iron absorption, possibly related to a defect of iron-induced hepcidin release.

Not Just Arterial Damage: Increased Incidence of Venous Thromboembolic Events in Cardiovascular Patients With Elevated Plasma Levels of Apolipoprotein CIII

Background

Apolipoprotein CIII (apo CIII) is a crucial player in triglyceride‐rich lipoprotein metabolism, but may also act pleiotropically, provoking inflammatory responses and stimulating coagulation. Elevated apoCIII plasma levels have been associated with increased activity of coagulation factors. Since these features of prothrombotic diathesis are linked with venous thromboembolism (VTE), we hypothesized that apo CIII plays a role in VTE.

Methods and Results

We recorded nonfatal VTE events in 1020 patients (age 63.3±11.4 years; 29.1% women) with or without coronary artery disease (79.1% with coronary artery disease and 20.9% without coronary artery disease) during a long follow‐up. Complete plasma lipid and apolipoproteins were available for all patients. Forty‐five patients (4.4%) experienced nonfatal VTE events during a median follow‐up period of 144 months. Apo CIII plasma concentration at enrollment was higher in patients with VTE compared with patients without VTE (12.2 [95% CI, 11.10–13.5] mg/dL vs 10.6 [95% CI, 10.4–10.9] mg/dL, respectively; P=0.011). Patients with apo CIII levels above the median value (10.6 mg/dL) exhibited an increased risk of VTE (incidence rate, 6.0 [95% CI, 4.0–8.0] vs 1.8 [95% CI, 0.7–2.9] VTE events/1000 person‐years; unadjusted hazard ratio [HR], 3.42 [95% CI, 1.73–6.75]; P<0.001). This association was confirmed after adjustment for sex, age, coronary artery disease diagnosis, body mass index, hypertension, and anticoagulant treatment at enrollment (HR, 2.66; 95% CI, 1.31–5.37 [P=0.007]), with inclusion of lipid parameters in the Cox model (HR, 3.74; 95% CI, 1.24–11.33 [P=0.019]), and even with exclusion of patients who died at follow‐up (HR, 3.92; 95% CI, 1.68–9.14 [P=0.002]) or patients taking anticoagulants (HR, 3.39; 95% CI, 1.72–6.69 [P<0.001]).

Conclusions

Our results suggest that high plasma apo CIII concentrations may predict an increased risk of VTE in patients with cardiovascular disease.

Increased Incidence of Ischemic Cerebrovascular Events in Cardiovascular Patients With Elevated Apolipoprotein CIII

Background and Purpose- Apo CIII (apolipoprotein CIII), a crucial regulator of lipoprotein metabolism, has been associated with increased activity of coagulation factors and thrombin generation and, in turn, with an increased risk of thromboembolic events in both arterial and venous districts. Thus, we hypothesized that it may affect the risk of acute ischemic cerebrovascular events in cardiovascular patients. Methods- We systematically checked medical records and quantified cerebral ischemic events in a cohort of 950 subjects (median age 65 with interquartile range, 55-79 years; 30.7% females) with or without angiographically defined coronary artery disease (CAD: 774 CAD and 176 CAD-free, respectively). All the subjects, enrolled between May 1999 and December 2006, were prospectively followed until death or July 31, 2018. Assessments of complete plasma lipid and apolipoprotein profiles, including Apo A-I, B, CIII, and E, were available for all subjects at enrollment. Results- After a median follow-up of 130 months (interquartile range, 69-189), 95 subjects (10%) suffered ischemic stroke/transient ischemic attack (TIA) events. Stroke/TIA subjects had higher Apo CIII plasma concentration (11.4; interquartile range: 9.3-14.4 mg/dL) at enrollment than those without stroke/TIA (10.4, interquartile range: 8.7-13.0 mg/dL). Subjects with Apo CIII levels above the median value (10.6 mg/dL) exhibited an ≈2-fold increased risk of stroke/TIA, even after adjustment for potential confounders, including sex, age, CAD diagnosis, hypertension, atrial fibrillation, oral anticoagulant treatment, and all plasma lipid parameters (hazard ratio: 2.23 [95% CI, 1.21-4.13]). This result was confirmed in CAD and CAD-free populations, separately, and even by a propensity score matching method, in which 98 CAD and 98 CAD-free subjects were one-to-one matched for all clinical and laboratory characteristics. Conclusions- These findings suggest that a high Apo CIII plasma concentration may predict an increased risk of ischemic stroke/TIA in cardiovascular patients.

Ultrasound as First Line Step in Anaemia Diagnostics

This review covers the role of ultrasonography as an essential non-invasive diagnostic approach when facing patients with anaemia, a common clinical problem. Abdomen ultrasound is well recognised as a first-line examination in the setting of blood loss, both acute and chronic. Less is clear about the additional opportunities, given by ultrasound in anaemia, due to the many other possible causes. Here we provide information on the utility of ultrasound in different contexts and a practical guide for clinicians facing anaemic patients.

Sialylated isoforms of apolipoprotein C-III and plasma lipids in subjects with coronary artery disease

BACKGROUND

Apolipoprotein C-III (ApoC-III), a key regulator of plasma triglyceride (TG), is present in three isoforms, i.e. non-sialylated (ApoC-III0), monosialylated (ApoC-III1) and disialylated (ApoC-III2). We aimed at quantifying the distribution of the ApoC-III glycoforms in patients with angiographically demonstrated coronary artery disease (CAD) according to levels of total ApoC-III plasma concentration.

METHODS

ApoC-III glycoforms were quantified by a specifically developed, high-resolution, mass spectrometry method in unrelated CAD patients. Lipoprotein lipase (LPL) activity was estimated by a fluorescence-based method.

RESULTS

In 101 statin-treated CAD patients, the absolute concentrations of the three glycoforms similarly increased across ApoC-III quartiles, but the proportion of ApoC-III1 rose whereas that of ApoC-III0 decreased progressively by increasing total ApoC-III concentrations. The proportion of ApoC-III2 was quite constant throughout the whole range of total ApoC-III. A higher proportion of ApoC-III1 reflected an unfavorable lipid profile characterized by high levels of TG, total and low density lipoprotein cholesterol, ApoE and reduced ApoA-I. The correlations between ApoC-III glycoforms and TG were confirmed in 50 statin-free CAD patients. High concentration of total ApoC-III was associated with low LPL activity, while no correlation was found for the relative proportion of glycoforms.

CONCLUSIONS

Specific patterns of ApoC-III glycoforms are present across different total ApoC-III concentrations in CAD patients. The inhibitory effect of ApoC-III on LPL appears related to total ApoC-III concentration, but not to the relative proportion of ApoC-III glycoforms.