Insights into the knowledge of complex diseases: Environmental infectious/toxic agents as potential etiopathogenetic factors of systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease secondary to three cardinal pathological features: immune-system alterations, diffuse microangiopathy, and fibrosis involving the skin and internal organs. The etiology of SSc remains quite obscure; it may encompass multiple host genetic and environmental -infectious/chemical-factors. The present review focused on the potential role of environmental agents in the etiopathogenesis of SSc based on epidemiological, clinical, and laboratory investigations previously published in the world literature. Among infectious agents, some viruses that may persist and reactivate in infected individuals, namely human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), and parvovirus B19 (B19V), and retroviruses have been proposed as potential causative agents of SSc. These viruses share a number of biological activities and consequent pathological alterations, such as endothelial dysfunction and/or fibroblast activation. Moreover, the acute worsening of pre-existing interstitial lung involvement observed in SSc patients with symptomatic SARS-CoV-2 infection might suggest a potential role of this virus in the overall disease outcome. A variety of chemical/occupational agents might be regarded as putative etiological factors of SSc. In this setting, the SSc complicating silica dust exposure represents one of the most promising models of study. Considering the complexity of SSc pathogenesis, none of suggested causative factors may explain the appearance of the whole SSc; it is likely that the disease is the result of a multifactorial and multistep pathogenetic process. A variable combination of potential etiological factors may modulate the appearance of different clinical phenotypes detectable in individual scleroderma patients. The in-deep investigations on the SSc etiopathogenesis may provide useful insights in the broad field of human diseases characterized by diffuse microangiopathy or altered fibrogenesis.

Detection of SARS-CoV-2 and Other Infectious Agents in Lower Respiratory Tract Samples Belonging to Patients Admitted to Intensive Care Units of a Tertiary-Care Hospital, Located in an Epidemic Area, during the Italian Lockdown

The aim of this study was the detection of infectious agents from lower respiratory tract (LRT) samples in order to describe their distribution in patients with severe acute respiratory failure and hospitalized in intensive care units (ICU) in an Italian tertiary-care hospital. LRT samples from 154 patients admitted to ICU from 27 February to 10 May 2020 were prospectively examined for respiratory viruses, including SARS-CoV-2, bacteria and/or fungi. SARS-CoV-2 was revealed in 90 patients (58.4%, 72 males, mean age 65 years). No significant difference was observed between SARS-CoV-2 positives and SARS-CoV-2 negatives with regard to sex, age and bacterial and/or fungal infections. Nonetheless, fungi were more frequently detected among SARS-CoV-2 positives (44/54, 81.4%, p = 0.0053). Candida albicans was the overall most frequently isolated agent, followed by Enterococcus faecalis among SARS-CoV-2 positives and Staphylococcus aureus among SARS-CoV-2 negatives. Overall mortality rate was 40.4%, accounting for 53 deaths: 37 among SARS-CoV-2 positives (mean age 69 years) and 16 among SARS-CoV-2 negatives (mean age 63 years). This study highlights the different patterns of infectious agents between the two patient categories: fungi were prevalently involved among SARS-CoV-2-positive patients and bacteria among the SARS-CoV-2-negative patients. The different therapies and the length of the ICU stay could have influenced these different patterns of infectious agents.

Human respiratory viruses, including SARS-CoV-2, circulating in the winter season 2019-2020 in Parma, Northern Italy

OBJECTIVES

The aim of this study was to determine the prevalence of respiratory virus infections, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), during the winter period December 2019 to March 2020, via a tertiary care hospital-based survey in Parma, Northern Italy.

METHODS

A total of 906 biological samples from the respiratory tract were analysed by both conventional assays (including culture) and molecular assays targeting nucleic acids of SARS-CoV-2 and other respiratory viruses.

RESULTS

Overall, 474 samples (52.3%) were positive for at least one virus, with a total of 583 viruses detected. Single infections were detected in 380 (80.2%) samples and mixed infections were detected in 94 (19.8%). Respiratory syncytial virus (138/583, 23.7%) and rhinovirus (130/583, 22.3%) were the most commonly identified viruses, followed by SARS-CoV-2 (82/583, 14.1%). Respiratory syncytial virus predominated until February, with 129 detections; it then decreased drastically in March to only nine detections. SARS-CoV-2 was absent in the study area until February 26, 2020 and then reached 82 detections in just over a month. SARS-CoV-2 was found in mixed infections in only three cases, all observed in children younger than 1 year old.

CONCLUSIONS

This study showed a completely different trend between SARS-CoV-2 and the 'common' respiratory viruses: the common viruses mostly affected children, without any distinction according to sex, while SARS-CoV-2 mostly affected adult males.

A Paradigmatic Interplay between Human Cytomegalovirus and Host Immune System: Possible Involvement of Viral Antigen-Driven CD8+ T Cell Responses in Systemic Sclerosis

Human cytomegalovirus (HCMV) is a highly prevalent opportunistic agent in the world population, which persists as a latent virus after a primary infection. Besides the well-established role of this agent causing severe diseases in immunocompromised individuals, more recently, HCMV has been evoked as a possible factor contributing to the pathogenesis of autoimmune diseases such as systemic sclerosis (SSc). The interplay between HCMV and immune surveillance is supposed to become unbalanced in SSc patients with expanded anti-HCMV immune responses, which are likely involved in the exacerbation of inflammatory processes. In this study, blood samples from a cohort of SSc patients vs. healthy subjects were tested for anti-HCMV immune responses (IgM, IgG antibodies, and T cells to peptide pools spanning the most immunogenic HCMV proteins). Statistically significant increase of HCMV-specific CD8+ T cell responses in SSc patients vs. healthy subjects was observed. Moreover, significantly greater HCMV-specific CD8+ T cell responses were found in SSc patients with a longer disease duration and those with higher modified Rodnan skin scores. Given the known importance of T cells in the development of SSc and that this virus may contribute to chronic inflammatory diseases, these data support a relevant role of HCMV-specific CD8+ T cell responses in SSc pathogenesis.

Human cytomegalovirus reactivation from latency: validation of a "switch" model in vitro

Background

Human cytomegalovirus (HCMV) is an opportunistic pathogen leading to severe and even fatal diseases in ‘at-risk’ categories of individuals upon primary infection or the symptomatic reactivation of the endogenous virus. The mechanisms which make the virus able to reactivate from latency are still matter of intense study. However, the very low number of peripheral blood monocytes (an important latent virus reservoir) harbouring HCMV DNA makes it very difficult to obtain adequate viral quantities to use in such studies.

Thus, the aim of the present study was to demonstrate the usefulness of human THP-1 monocytes, mostly employed as HCMV latent or lytic infection system, as a reactivation model.

Methods

THP-1 monocytes were infected with HCMV TB40E strain (latency model) at multiplicities of infection (MOI) of 0.5, 0.25 or 0.125. After infection, THP-1 aliquots were differentiated into macrophages (reactivation model). Infections were carried out for 30 h, 4, 6 and 7 days. Viral DNA evaluation was performed with viable and UV-inactivated virus by q-Real-Time PCR. RNA extracted from latency and reactivation models at 7 days post-infection (p.i.) was subjected to RT-PCR to analyse viral latency and lytic transcripts. To perform viral progeny analysis and titration, the culture medium from infected THP-1 latency and reactivation models (7 days p.i.) was used to infect human fibroblasts; it was also checked for the presence of exosomes.

For viral progeny analysis experiments, the Towne strain was also used.

Results

Our results showed that, while comparable TB40E DNA amounts were present in both latent and reactivation models at 30 h p.i., gradually increased quantities of viral DNA were only evident in the latter model at 4, 6, 7 days p.i.. The completion of the lytic cycle upon reactivation was also proved by the presence of HCMV lytic transcripts and an infectious viral yield at 7 days p.i.

Conclusions

Our data demonstrate the effectiveness of THP-1 cells as a “switch” model for studying the mechanisms that regulate HCMV reactivation from latency. This system is able to provide adequate quantities of cells harbouring latent/reactivated virus, thereby overcoming the intrinsic difficulties connected to the ex vivo system.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0634-z) contains supplementary material, which is available to authorized users.

Abstract 4652: Wide antiproliferative and proapoptotic activity of the natural prenyl-flavonoid Xanthohumol and its derivatives on cancer cells, peripheral blood mononuclear cells, and human primary endothelial cells

Chemo-preventive drugs are molecules able to prevent or retard cancer development and progression. Recently, diet flavonoids have been recognized as chemo- and angio-preventive agents. Among these, Xanthohumol (XN), is the principal prenylated chalcone of the female inflorescence of the hop plant (Humulus lupulus L.) with chemo-/angio-preventive properties. The biological effects of the chalcones mostly depend on their chemical structure, whose variations influence their anti-tumor effects. In order to identify novel potential chemo-/angio-preventive agents, we analyzed the effects of seven synthetic derivatives of XN on tumor and normal cells. We used different tumor cell lines (lymphoma, colon and prostate cancer cell lines) and healthy human primary cells (mononuclear cells isolated from peripheral blood (PBMCs) and umbilical vein endothelial cells (HUVEC)). XN derivatives have a lower IC50 on both cancer and normal cells as compared to XN. XN10 exerts the highest anti-proliferative activity in cancer and normal primary cells and we therefore focused our experiments on this compound in comparison with XN master molecule. Interestingly, the IC50 values for XN10 are two-three fold higher in primary cells than tumor cells, suggesting an anti-tumor effect of XN10 which spares healthy cells both from peripheral blood and the microenvironment. The treatment with XN10 leads to apoptosis as demonstrated in lymphoma cell lines by PARP-1 cleavage and dose-dependent caspase-3 activation. Preliminary data also show that XN downregulates the enzyme cyclooxygenase-1 while inducing a DNA damage as demonstrated by the increase of the specific marker γ-H2AX in the cell lysates treated with the indicated drugs. We then treated both PBMCs and HUVECs with XN and XN10 in a range of 1-20μM for 48 hr. XN10 affects PBMCs and HUVEC cells viability starting at lower doses (1 μM) than the parental molecule. 20μM XN mainly decreases monocyte population whereas XN10 affects both

CD19+/CD20+ and CD14+/CD33+ cells in parallel with the increase of apoptosis and caspase activation. Further, in HUVECs, XN activates AMPK in a time and dose-dependent manner with a peak of activation after 5 minutes of exposure up to 1h, independently from LKB1 activation. Activation of AMPK signalling pathway by XN was confirmed by ACC phosphorylation at Ser-79 at the same timepoints. In this cellular context, XN modulates AMPK downstream target, mTOR and eNOS, particularly inhibiting eNOS phosphorylation. Collectively, our data show that XN and its novel derivative XN10 exert a strong antiproliferative activity on a variety of tumor cell lines and normal cells. XN10 features the strongest pro-apoptotic activity yet causing the most dramatic cytotoxic effect on normal cells. Moreover, XN activity seems to involve AMPK activation, in HUVEC cells.

Citation Format: Katiuscia Dallaglio, Valentina Fragliasso, Cristina Gallo, Raffaele Frazzi, Clara Maccari, Armando Rossello, Adriana Albini. Wide antiproliferative and proapoptotic activity of the natural prenyl-flavonoid Xanthohumol and its derivatives on cancer cells, peripheral blood mononuclear cells, and human primary endothelial cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4652. doi:10.1158/1538-7445.AM2015-4652

Linezolid levels in a patient with biliary tract sepsis, severe hepatic failure and acute kidney injury on sustained low-efficiency dialysis (SLED)

We report on a patient with biliary sepsis due to Vancomycin-resistant Enterococcus faecium (VRE) treated with linezolid (LNZ), who had both hepatic failure and acute kidney injury requiring daily sustained low-efficiency dialysis (SLED), a new intermittent, prolonged diffusive modality of renal replacement therapy for ICU patients. Following cholecystostomy and peritoneal drain insertion, serum, bile and peritoneal fluid serial samples were simultaneously collected for LNZ concentration measurement (chromatography/mass spectrometry). Unusually high serum antibiotic levels (20 mg/L or more) were achieved as early as 36 hours since the start of LNZ administration, owing to relatively low hepatic clearance. Serum LNZ leveled off after commencing SLED, apparently reaching steady state levels. The lowest values of Cmin in bile was 5.86 mg/L; the average serum and bile AUC0-12 over the observation period were 204 mg/L*h and 276 mg/L*h, with a AUC0-24/MIC ratio of 227 h and 307 h, respectively. The excellent biliary pharmacodynamic exposure suggests that standard-dose LNZ might represent a valuable choice in severe biliary infection, even in the presence of hepatic failure, when the patients receive highly efficient modalities of renal replacement therapy.

The patient with a severe degree of metabolic acidosis: a deductive analysis

This teaching exercise demonstrates how principles of physiology might help in identifying the cause of a particularly severe case of metabolic acidosis and making appropriate decisions about therapy. The patient's plasma pH was 7.00 and their plasma bicarbonate concentration was 2 mmol/l. Because the time course of the patient's illness was believed to be <24 h, this suggested that a large quantity of acid had been added to the body in this short time period, but the medical team managing the case could not identify any acid that could have been produced rapidly by endogenous processes, or was ingested by the patient. Moreover, there was a question about how such a very low arterial PCO(2) (8 mmHg) could be sustained. Even once the diagnosis was made, there were issues to resolve concerning therapy. These included questions about how much sodium bicarbonate to administer, and what dangers might arise during this therapy. The missing links in this interesting story emerge during a discussion between the medical team and their imaginary mentor, Professor McCance.

[Intensive care and resuscitation: visits to hospitalized patients]

The nurse's opinion and their feelings and attitudes toward the parents visits in coronary (CCU) and intensive care (ICU) units was evaluated. A questionnaire with closed questions was sent to 60 coronary care and intensive care units respectively. 50 questionnaires (41.6% were returned). Patients access to the wards is very dishomogeneous, with greater variability among ICUs. On average, patients are allowed to visit their relatives 1.35 hour/day, divided in two entry times. Only in 19% of wards (38 wards) there are exceptions to these rules. Nurses are not allowed to give any kind of information to relatives in 25% of wards, because this is considered a doctors' task. Probably the part of the limitations to the access of the relatives are due to organizative problems, but, according to the nurses, there are major opportunities for improvement.