Epidemiology of pathogens causing acute diarrhea in patients presenting to the emergency departments in 4 hospitals in Lebanon

Acute diarrhea is a prevalent disease worldwide and a cause of mortality in low and middle-income countries. In previous studies, the causative enteropathogen is found in 38% to 58% of patients, leaving a considerable diagnostic gap. In this study, we intend to determine the pathogenic agents responsible for acute diarrhea in patients presenting to the Emergency Departments of several Lebanese hospitals. A total of 100 stool samples were collected between June 2022 and June 2023 from patients presenting with acute diarrhea to the Emergency Departments. Pathogens were detected by multiplex polymerase chain reaction. The average age for the patients was 53 years old. All patients presented with diarrhea, 15 of them had fever associated. In total, 46 patients were admitted to the hospital (70%), among them 80% received Intravenous antibiotics. Campylobacter was the most common agent detected in 36%, followed by Rotavirus 19%, and Noroviruses 15%. The rest was detected at lower percentages. Bacteria accounted for 49% of cases, viruses for 39%, and parasitic infection 6%. Acute diarrhea epidemiology is understudied in Lebanon. This study is the first Lebanese data about acute diarrhea pathogens. Avoiding overuse of antibiotics in bacterial versus viral infections can be achieved while prevention campaigns can raise awareness about food and water safety at the community level.

Antimicrobial effects of chlorine dioxide in a hospital setting

Chlorine dioxide is a powerful disinfectant with strong antibacterial properties. We conducted a study at different sites of the Lebanese American University Medical Center-Rizk Hospital to determine the efficacy of the ECOM air mask in decreasing the particle load. Air cultures were obtained from three different locations, namely the patients' elevator, visitors' elevator and mobile clinic and the number of colonies grown on each type of agar was determined. We also measured particle counts at the three sites both at baseline and after placement of the ECOM air mask. After 7 days of ECOM air mask use, the numbers of colonies grown on all types of media was decreased by 20-100% versus the baseline values. The counts of particles of different diameters (0.3, 0.5 and 5 µm) were decreased at all three sampled sites. This study highlighted the efficacy of the ECOM air mask. The utility of the gaseous form of ClO2 as an antiseptic in the hospital setting appears promising.

Lower odds of COVID-19-related mortality in hospitalised patients with type II diabetes mellitus: A single-centre study

BACKGROUND

COVID-19 infection in patients with type 2 diabetes mellitus (T2DM) -a chronic illness in Lebanon-is not well described.

METHODS

This was a single-centre retrospective observational study of 491 patients, including 152 patients with T2DM, who were hospitalised for COVID-19 between 20 August 2020 and 21 April 2021. Data on clinical characteristics, laboratory and radiological findings and outcomes were collected from the electronic medical records. Clinical characteristics and in-hospital mortality between patients with and without T2DM infected with COVID-19 using multivariate analysis were compared.

RESULTS

Patients with T2DM were significantly older than those without T2DM (mean age, 68.7 vs. 60.3 years). Patients with T2DM were more likely to present with a body temperature of <38.3°C (83.9% vs. 69.9%) and less likely to present with chest pain (3.9% vs. 9.1%) and sore throat (2.0% vs. 6.8%). Patients with T2DM were more likely to be hypertensive (76.35% vs. 41%) and dyslipidaemic (58.6% vs. 25.7%) and had more frequent underlying coronary artery disease (33.6% vs. 12.4%). The rates of patients with creatinine levels of ≥1.17 mg/L and troponin T levels of ≥4 ng/dL were higher in the T2DM group than in the non-T2DM group (30.4% vs. 15% and 93.3% vs. 83.1%, respectively). Patients with T2DM were more likely to be admitted to the intensive care unit (ICU) (34.2% vs. 22.1%), require invasive ventilation (18.4% vs. 10.3%) and receive vasopressors (16.4% vs. 10.0%). Increasing age and the use of invasive ventilation and vasopressors were associated with higher odds of mortality (odds ratio (OR), 1.08, 9.95 and 19.83, respectively), whereas longer ICU stay was associated with lower odds of mortality (OR, 0.38). The odds of mortality were lower in the T2DM group than in the non-T2DM group (OR, 0.27).

CONCLUSION

Among patients hospitalised for COVID-19, those with T2DM were older, presented with milder symptoms and had more comorbidities and higher troponin T levels compared with those without T2DM. Despite the worse clinical course, the patients with T2DM had lower odds of mortality than those without T2DM.

Evolution of COVID-19 infection characteristics in a Lebanese cohort of inpatients during different pandemic periods

This study aims to describe COVID-19 patients characteristics, laboratory and imaging results, and the different outcomes of patients admitted to the Lebanese American University Medical Center-Rizk Hospital over a period of 9 months. In this observational retrospective study, data were obtained from electronic medical records of 491 male and female patients from the ages of 17 to 97. Analysis of the patients was performed in 3 periods: August 2020 to October 20 November 202020 to January 2021 and February 2021 to April 2021 corresponding with 3 waves of newly diagnosed cases during this period. The sample showed a male predominance with an average age of 63. The average hospitalization length was 10.1 days. The majority of patients were discharged to quarantine. The distribution of hospitalized cases was significantly correlated to the monthly distribution of newly COVID-19 cases in Lebanon. There was no significant difference in patient's characteristics between the 3 periods of the study (gender, age, body mass index, smoking, and medical conditions). Clinical presentations of the patients varied between the 3 periods. Similarly, the course and outcome of infection varied. Patients received less oxygen during period 1, while more patients were cured during period 3. This study presents the first Lebanese cohort of COVID-19 patients with their medical background, clinical presentation, laboratory results, radiological findings and course of infection with its outcome. It also shows how the relations between the medical manifestation of the COVID-19 pandemic and the socio-political measures of infection control are deeply intertwined.

Effect of combination of prophylactic or therapeutic anticoagulation with aspirin on the outcomes of hospitalized COVID-19 patients: An observational retrospective study

Regimens for managing thromboembolic complications of COVID-19 are still not very well established. The present study compares the clinical characteristics and outcomes of patients hospitalized with COVID-19 receiving different anticoagulation regimens with and without aspirin. This is a retrospective observational study of 491 patients hospitalized for COVID-19 from August 2020 to April 2021. Data regarding clinical characteristics, laboratory findings, and outcomes of patients receiving different anticoagulation with and without aspirin regimens was collected, according to which 5 patient groups were defined: received no anticoagulation (NAA), prophylactic anticoagulation with (PA) or without aspirin (PAA) and therapeutic anticoagulation with (TA) or without aspirin (TAA). The average age was highest in the TAA group. Desaturation was highest in the TA and TAA groups. Diabetes, hypertension, dyslipidemia and coronary artery disease were the most prevalent in aspirin groups (PAA and TAA) as was heart failure in the TA and TAA groups and cancer in the TA and PAA groups. Elevated troponin was observed in the PAA and TAA groups. TA and TAA patients received oxygen therapy, needed ICU admission overall, and required invasive ventilation and vasopressors the most. Prophylactic anticoagulation groups (PA and PAA) had the highest patient survival rates. Patients with severe COVID-19 infections were more likely to receive higher, therapeutic, anticoagulation doses. Aspirin was given to patients with preexisting comorbidities, but it had no statistically significant impact on the outcomes of the different groups. Groups receiving prophylactic anticoagulation had the best survival outcomes.

The Silent Threat: A Case of Iatrogenic Asymptomatic Aortic Dissection Post Coronary Artery Bypass Grafting

Asymptomatic aortic dissection (AD) is a rare but potentially life-threatening complication that can occur following coronary artery bypass graft (CABG) surgery. While CABG is a well-established surgical procedure for managing multivessel coronary artery disease, it can inadvertently predispose patients to the development of AD, especially in those with pre-existing aortic pathology. The pathophysiology underlying AD after CABG is multifactorial, with factors, such as atherosclerosis, manipulation of the aorta during surgery, and hemodynamic stress, playing significant roles. Notably, the absence of symptoms poses a diagnostic challenge, as patients may remain unaware of the underlying condition until a catastrophic event occurs. Therefore, a high index of suspicion and vigilant postoperative monitoring are crucial in identifying asymptomatic AD. Diagnostic modalities including imaging techniques, such as computed tomography angiography (CTA), magnetic resonance imaging (MRI), and echocardiography, play pivotal roles in confirming the diagnosis and determining the extent of the dissection. Prompt surgical intervention is generally recommended in symptomatic patients or those with evidence of impending complications. We hereby present a case report of a patient who presented with asymptomatic AD post CABG surgery and discuss the pathophysiology, presentation, diagnostic workup, and treatment options.

A Journey From Cardiology to Oncology Reveals a Rare Case of Primary Intimal Sarcoma in a Patient With Dyspnea: A Case Report

Primary intimal sarcoma of the pulmonary artery is a rare and aggressive malignancy that arises from the intimal layer of the pulmonary artery. It typically presents with nonspecific symptoms such as dyspnea, chest pain, and hemoptysis, making early diagnosis challenging. Computed tomography (CT) and magnetic resonance imaging (MRI) are useful in identifying the tumor's location and extent. A definitive diagnosis is established by biopsy, either via surgical resection or percutaneous needle biopsy. However, diagnosis can be difficult due to the rarity of the disease and the need for specialized expertise in interpreting pathology specimens. Treatment of primary intimal sarcoma of the pulmonary artery involves surgical resection, followed by adjuvant chemotherapy and radiation therapy. Despite aggressive treatment, the prognosis remains poor, with a median survival of approximately two years. However, early detection and aggressive multimodal therapy can improve outcomes. We hereby report a rare case of primary intimal sarcoma of the pulmonary artery and discuss its pathophysiology, presentation, diagnostic approach, and treatment options.

Pneumonia, Arthritis, and Liver Injury: A Cardiac Diagnostic Conundrum

A 40-year-old intravenous cocaine user presented with non-specific symptoms, including fever, headache, myalgias, and fatigue. After being provisionally diagnosed with rhinosinusitis and discharged on antibiotics, the patient returned with shortness of breath, dry cough, and persistent high-grade fevers. Initial workup showed multifocal pneumonia, acute liver injury, and septic arthritis. Blood cultures were positive for methicillin-sensitive staphylococcus aureus (MSSA) which led to the evaluation of endocarditis with a transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE). TEE was performed as the initial diagnostic imaging test, and it did not show any evidence of valvular vegetation. However, given the persistence of the patient's symptoms and clinical suspicion of infective endocarditis, TTE was performed which showed a 3.2 cm vegetation on the pulmonic valve with severe insufficiency, leading to a diagnosis of pulmonic valve endocarditis. The patient was treated with antibiotics and underwent a pulmonic valve replacement surgery, which showed a large vegetation on the ventricle portion of the pulmonic valve that was replaced with an interspersed tissue valve. The patient was discharged in stable condition after improvement of symptoms and normalization of liver function enzymes. It is important to note that TTE should be considered initially as a diagnostic tool in such cases. Sometimes, a TEE may not be required if the TTE provides a sufficient assessment.

Acute Colonic Pseudo-Obstruction in a Patient With COVID-19 Pneumonia: A Case Report

Coronavirus disease (COVID-19) is primarily a respiratory illness caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. However, the disease is also known to cause a range of extrapulmonary manifestations, including gastrointestinal (GI) symptoms such as nausea, vomiting, and diarrhea. The exact mechanisms by which the virus causes extrapulmonary manifestations are not fully understood, but it is theorized that the virus can enter cells in other organs including the GI tract, through the angiotensin-converting enzyme 2 (ACE2) receptor. This can result in inflammation and damage to the affected organs. In rare cases, COVID-19 can also cause acute colonic pseudo-obstruction (ACPO), a condition characterized by symptoms of bowel obstruction but without a physical obstruction present. Acute colonic pseudo-obstruction is a serious and potentially life-threatening complication of COVID-19 that requires prompt recognition and treatment to prevent further complications such as bowel ischemia and perforation. We hereby present a case report of a patient with COVID-19 pneumonia developing ACPO and discuss the suggested pathophysiology, diagnostic approach, and treatment options.

Erythrocytes from patients with ST-elevation myocardial infarction induce cardioprotection via the purinergic P2Y13 receptor and nitric oxide signalling

Background

Red blood cells (RBC) are suggested to act as important mediators in the regulation of cardiovascular function by exporting nitric oxide (NO) bioactivity and ATP under hypoxic/ischemic conditions. In addition, RBCs are known to protect from ischemia-reperfusion injury via the export of NO bioactivity in experimental settings. However, it remains unknown if such beneficial effects of RBCs are protective in patients with acute myocardial infarction.

Purpose

To investigate whether RBCs from patients with ST-elevation myocardial infarction (STEMI) protect against myocardial ischemia-reperfusion injury and whether such effect involves activation of purinergic and NO signalling in the RBCs.

Methods

RBCs were collected from patients with STEMI undergoing primary percutaneous coronary intervention and age- and gender-matched healthy controls. The RBCs were administered into the coronary circulation of isolated Langendorff-perfused rat hearts at the onset of global ischemia for 25 min followed by reperfusion of 60 min. Recovery of left ventricular developed pressure (LVDP) during reperfusion and infarct size were determined. All animal experiments and procedures were performed according to the guidelines by the U.S National Institutes of Health (NIH publication no 85–23, revised 1996). The present study was performed following The Code of Ethics of the World Medical Association outlined in the Declaration of Helsinki of 1975 and revised in 1983 for experiments that involve human subjects.

Results

Administration of RBCs from STEMI patients improved recovery of LVDP and reduced infarct size in hearts subjected to ischemia-reperfusion in comparison with RBCs from healthy controls (Figure 1A, B). Pre-incubation of the RBCs with the NO synthase (NOS) inhibitor L-NAME (Figure 1C, D) and the inhibitor of the NO receptor soluble guanylyl cyclase (sGC) ODQ abolished the cardioprotective effect of RBCs from STEMI patients. The cardioprotective effect was also attenuated by inhibition of cardiac cGMP-dependent protein kinase (PKG). Further, the purinergic P2Y13 receptor antagonist MRS2211 (Figure 1E, F), but not the P1 receptor antagonist 8PT applied to RBCs, attenuated the cardioprotection induced by RBCs from STEMI patients. Moreover, administration of RBCs from healthy subjects pre-incubated with a cell permeable ATP analogue improved post-ischemic recovery of LVDP and reduced infarct size. This cardioprotective effect was abolished by co-incubation of the RBCs with ODQ (Figure 2) and MRS2211.

Conclusion

Our findings demonstrate a novel function of RBCs in patients with STEMI that provides protection against myocardial ischemia-reperfusion injury via the activation of P2Y13 receptor and the NO-sGC pathway in RBCs and cardiac PKG.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Lung Foundation; Swedish Research Council

Red blood cells induce endothelial dysfunction in patients with ST-elevation myocardial infarction and elevated C-reactive protein

Background

The important role of inflammation in atherosclerotic plaque progression and instability leading to myocardial infarction has been widely demonstrated. C-reactive protein (CRP) has been shown to be of predictive value in atherosclerotic cardiovascular disease. The red blood cell (RBC) is an important regulator of cardiovascular function through nitric oxide bioactivity and oxidative stress in ischemic heart disease. Also, arginase-1 has been shown to greatly influence nitric oxide bioactivity in RBCs and to cause endothelial dysfunction. However, the mechanisms by which RBCs regulate vascular function in patients with myocardial infarction and its relation to inflammation and arginase-1 remain unknown.

Objective

The study aimed to investigate the effect of RBCs on endothelial function in patients with ST-elevation myocardial infarction (STEMI) and its possible association with systemic inflammation and arginase-1.

Material and methods

Blood samples were collected from patients with STEMI within 36 h after admission and from age-matched healthy controls. RBCs were incubated with isolated rat aortic segments for 18 h after which the aortas were assessed for endothelium-dependent and endothelium-independent relaxations using wire myographs and application of acetylcholine and nitroprusside, respectively. The vascular response was evaluated in relation to the level of inflammation defined as CRP &lt;2 and ≥2 mg/L at admission. The levels of 4-hydroxynonenal (4-HNE; a marker of oxidative stress formed by lipid peroxidation) and the expression of arginase-1 were visualized in rat aortas following incubation with RBCs by immunohistochemistry. All handling and procedures regarding human subjects and sampling were performed according to the Declaration of Helsinki. All animal experiments and procedures were performed according to the guidelines by the U.S National Institutes of Health (NIH publication no 85–23, revised 1996).

Results

RBCs from patients with STEMI and elevated CRP (≥2 mg/L, mean of 9.6 mg/L) induced significant impairment of endothelium-dependent relaxation compared to RBCs from patients with STEMI and low CRP (&lt;2 mg/L, mean of 1.0 mg/L) and to the healthy controls (Fig. 1). Endothelium-independent relaxations did not differ between the groups. Immunohistochemical staining of the aorta revealed that incubation with RBCs from patients with STEMI and high CRP increased the expression of 4-HNE and arginase-1 compared to incubation of RBCs from healthy controls and patients with STEMI and low CRP (Fig. 2).

Conclusion

RBCs from patients with STEMI and elevated CRP induce endothelial dysfunction and increase the expression of 4-HNE and arginase-1, indicating that inflammation is involved in the mechanism by which RBCs induce endothelial dysfunction in STEMI.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Lung foundation

Transcatheter tricuspid valve intervention techniques and procedural steps for the treatment of tricuspid regurgitation: a review of the literature

Severe tricuspid regurgitation (TR) is an undertreated common pathology associated with significant morbidity and mortality. Classically, surgical repair or valve replacement were the only therapeutic options and are associated with up to 10% postprocedural mortality. Transcatheter tricuspid valve interventions are a novel and effective therapeutic option for the treatment of significant TR. Several devices have been developed with different mechanisms of action. They are classified as annuloplasty devices, replacement devices, caval valve implantation and coaptation devices. In this review, we provide a step-by-step description of the procedural steps and techniques of every device along with video support.

POS1465 COMPLICATED QUESTIONS YET SIMPLE ANSWERS. A CASE OF THIAMIN DEFICIENCY MISTAKEN FOR SJOGREN’S SYNDROME

Background

Sialosis is a non inflammatory nor neoplastic expansion of the salivary glands. it is a common mimicker for obstructive, inflammatory and malignant salivary gland disorders.(1) It had been described in acromegaly, vitamin A, and Thiamin deficiency and in amylophagia and bulimia.(2-5) Imaging should be normal in Sialosis(6) Here we describe a case of Sialosis due to Vitamin deficiency who was treated for a few months with anti-tuberculous and anti inflammatory drugs.

Objectives

To raise awareness about this cause of parotid swelling and encourage practice of exclusion prior to treatment.

Methods

A 30 year old lady with no significant past medical history presented to us with 2 years of slowly progressive, non tender bilateral facial swellings, with no excess or reduced salivation and no pain upon eating, she had negative history of preceding upper respiratory tract infection. the condition was associated with feeling a lump in her right axilla, and cervical region, there was no fever or systemic manifestations. she consulted a surgeon during that period, an exisional biopsy of the lump revealed the presence of fatty lumps, she was then prescribed antituberculosis medications since her symptoms were vague and because TB is quite common in Iraq. She denied any improvement with these medications. She then was prescribed treatment with hydroxyChloroquin and prednisolone by another physician assuming she had sjogren’s syndrome. When we saw the patient she was extremely distressed and depressed, had bilateral diffused parotid swellings, along with submandibular swelling, no mass could be felt during the exam, her mandibles and neck appeared large, she had normal tear film production and negative eye test, with no articular or muscular abnormalities.

Results

Her Labs were negative, and ultrasound for the parotids revealed enlarged glands with normal texture, MRI showed enlarged both parotids and submandibular glands with no other abnormality, minor salivary gland biopsy showed normal tissue with no inflammatory cell infiltrates. she had normal thyroid, parathyroid and growth hormone levels, normal metabolic panel and denied history of Alcohol consumption of Bulimia, but rarely consumed meat. a trial of Vitamin A, Thiamin and pilocarpine was started, the patient reported regression in the size of the swellings after 2 weeks of therapy but then developed mucosal dryness, afterwards, Vitamin A was stopped, she developed bone pain with normal bone markers and for that reason, pilocarpine was stopped. despite stopping these medicines, the size continued to regress on thiamin supplement alone, and she was prescribed anxiolytics and antidepressants by a Neurologist.

Figure 1.

Showing the appearance A, before and B after one month of treatment.

Conclusion

Sialosis can be a manifestation of variable metabolic and endocrine conditions and it should be kept in mind when facing a patient with parotid swelling being a potentially treatable cause.

References

[1]References in Sialosis: 35 cases of persistent parotid swelling from two countries - British Journal of Oral and Maxillofacial Surgery [Internet]. [cited 2022 Jan 20]. Available from: https://www.bjoms.com/article/S0266-4356(08)00040-5/references

[2]Salivary Swelling | Iowa Head and Neck Protocols [Internet]. [cited 2022 Jan 20]. Available from: https://medicine.uiowa.edu/iowaprotocols/salivary-swelling

[3]Yu YH, Park YS, Kim SH, Son BK, Jun DW, Jo YJ, et al. Sialadenosis in a Patient with Alcoholic Fatty Liver Developing after Heavy Alcohol Drinking. Korean J Gastroenterol. 2009 Jul 31;54(1):50–4.

[4]Scully C, Eveson J. Sialosis and necrotising sialometaplasia in bulimia; a case report. International Journal of Oral and Maxillofacial Surgery. 2004 Dec 1;33(8):808–10.

[5]Scully C, Bagán JV, Eveson JW, Barnard N, Turner FM. Sialosis: 35 cases of persistent parotid swelling from two countries. British Journal of Oral and Maxillofacial Surgery. 2008 Sep;46(6):468–72.

[6]Sialosis | Radiology Reference Article | Radiopaedia.org [Internet]. [cited 2022 Jan 20]. Available from: https://radiopaedia.org/articles/sialosis-1

Disclosure of Interests

None declared

Erythrocytes induce vascular dysfunction in COVID-19

Background

Vascular injury has been implicated as a major cause of clinical complications in patients with coronavirus disease 2019 (COVID-19). Autopsy studies have revealed destruction of the endothelial cell lining, which might explain cardiovascular alterations arising from the infection. However, data demonstrating endothelial dysfunction during ongoing infection are sparse, and the underlying mechanisms are still largely unknown. Red blood cells (RBCs) are affected by COVID-19 with alterations in their structure and function, possibly contributing to vascular injury via increased oxidative stress.

Purpose

To determine the presence of endothelial dysfunction in patients with COVID-19 and to explore the RBC as a possible mediator of such dysfunction.

Methods

The study was performed on 17 patients hospitalized for moderate COVID-19 infection and age- and sex-matched healthy subjects. Inclusion criteria of the COVID-19 patients were PCR-verified SARS-CoV2 infection, pulmonary infiltrates on x-ray, oxygen demand during hospital stay and ≤ one cardiovascular co-morbidity. Microvascular endothelial function in vivo was assessed with a pulse amplitude tonometry device on each index finger at baseline and during reactive hyperemia and expressed as reactive hyperemia index (RHI). RBCs from COVID-19 patients (C19-RBCs) and healthy subjects (H-RBCs) were incubated with isolated rat aortic segments for evaluation of endothelium-dependent and -independent relaxation.

Results

COVID-19 patients displayed profound impairment in endothelial function in vivo with RHI 1.56 (1.30–1.81, median and interquartile range) compared to healthy subjects 2.36 (1.97–2.79, p&lt;0.001). C19-RBCs induced severe impairment in both endothelium-dependent (27% maximal relaxation) and -independent relaxations (54%) compared to H-RBCs (67% and 95% relaxation, respectively). Further, C19-RBCs induced upregulation of vascular arginase 1 (∼2 fold increase compared to H-RBCs) and markers of oxidative stress (∼6 fold). Consequently, inhibition of vascular arginase or superoxide attenuated the impairment in endothelial function induced by C19-RBCs. C19-RBCs were characterized by increased production of reactive oxygen species (∼1.4 fold) and reduced export of the nitric oxide metabolite nitrate. Following pre-incubation with interferon-γ, but not interleukin-6 or tumor necrosis factor-α, H-RBCs induced impairment in endothelial function.

Conclusions

This study demonstrates the presence of marked endothelial dysfunction in an otherwise mainly healthy patient group hospitalized for COVID-19, and clearly implicates a central role of the RBC as a mediator of endothelial injury through enhancement of reactive oxygen species and arginase. These data shed light on a new pathological mechanism underlying vascular dysfunction in COVID-19 patients and may lay the foundation for future therapeutic developments.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Lung foundationSwedish Research Council

Attenuated cardiac post-ischemic injury and endothelial dysfunction by stimulation of soluble guanylyl cyclase in red blood cells from patients with type 2 diabetes

Background

Reduced bioavailability of nitric oxide (NO) contributes to ischemic heart disease in type 2 diabetes (T2D). Red blood cells (RBCs) are known to produce NO bioactivity and to contain a functional soluble guanylyl cyclase (sGC) that is activated by NO. Recent studies revealed that RBCs from patients with T2D exacerbates ischemia-reperfusion (I/R) injury and induces endothelial dysfunction via a mechanism that is dependent on reduced export of NO bioactivity from RBCs. It remains unknown whether stimulation of sGC in RBCs from patients with T2D protects against myocardial I/R injury and endothelial dysfunction.

Purpose

To test the hypothesis that stimulation of sGC in RBCs from T2D patients protects against myocardial I/R injury and improves endothelial function.

Methods

RBCs collected from T2D patients and healthy subjects were incubated with vehicle or the sGC stimulator CYR715 before being administered to isolated Langendorff-perfused rat hearts subjected to 25 min global ischemia and 60 min reperfusion. Left ventricular developed pressure (LVDP) and infarct size were determined. In addition, isolated rat aortic rings were incubated with RBCs subsequent determination of endothelium-dependent relaxation (EDR).

Results

Administration of RBCs from T2D patients impaired post-ischemic recovery of LVDP and induced endothelial dysfunction in comparison with RBCs from healthy subjects (P&lt;0.001). Pre-incubation of RBCs from patients with T2D with CYR715 prior to administration to the isolated heart enhanced the recovery of LVDP (Fig.1A), reduced infarct size (Fig.1B), and attenuated endothelial dysfunction (Fig.1C). CYR715 did not induce cardioprotection in the absence of RBCs. The sGC inhibitor ODQ did not significantly affect cardiac recovery per se but totally abolished the protective effect of CYR715 (Fig.1A).

Conclusions

Stimulation of sGC in RBCs from patients with T2D protects against cardiac I/R injury and prevents development of endothelial dysfunction. Stimulation of the NO-sGC pathway in RBCs appears to be an attractive therapeutic strategy to prevent cardiovascular injury in T2D.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Lung Foundation, the Swedish Research Council

Remote ischemic conditioning fails to protect against ischemia-reperfusion injury in patients with untreated familial hypercholesterolemia

Background/Introduction

Remote ischemic conditioning (RIC) is the action of brief periods of ischemia to a remote tissue and has been suggested to protect against myocardial ischemia-reperfusion (IR) injury. The outcomes of clinical trials in terms of clinical endpoints and infarct size reduction have been variable, which may be related to influence of comorbidities on the effect of RIC. Animal studies suggest that hypercholesterolemia attenuates the cardioprotective effect of RIC, but no data from study on patients are available. Hence, our aim was to investigate the response of RIC on IR-induced endothelial dysfunction in patients with familial hypercholesterolemia (FH).

Purpose

To investigate if RIC protects against endothelial dysfunction induced by IR in patients with FH with high (≥5.5 mmol/L) and low (≤2.5 mmol/L) LDL-cholesterol levels.

Methods

All subjects with FH (n=12) with LDL ≥5.5 mmol/L, FH with LDL &lt;2.5 mmol/L (n=12), and age-matched healthy control subjects (n=12) participated in two protocols separated by at least one week. In both protocols, endothelium-dependent vasodilatation was assessed by determination of flow-mediated vasodilatation (FMD) of the brachial artery at baseline and again after 20 minutes of forearm ischemia and 20 minutes of reperfusion. Forearm ischemia was induced by inflating a blood pressure cuff on the upper arm to 200 mmHg. An additional inflatable cuff was placed around the left thigh. In one protocol (IR+sham), this cuff was left uninflated. In the second protocol (IR+RIC), it was inflated to 200 mmHg in four cycles of 5 minutes inflation and 5 min deflation with the first cycle starting at the onset of forearm ischemia.

Results

Plasma mean LDL-cholesterol was significantly higher in the FH group with high LDL (6.6±1.4 mmol/L) compared to the control group (2.4±0.7 mmol/L; p&lt;0.01) and the low LDL FH group (2.0±0.6 mmol/L; p&lt;0.001). FMD was markedly reduced (p&lt;0.05) in all subjects following IR+sham, indicating IR-induced endothelial dysfunction in all three groups. As expected, RIC prevented the reduction in FMD after IR in the control group (Fig 1). By contrast, in the FH group with high LDL, RIC failed to protect from IR-induced endothelial dysfunction. Thus, in this group the decrease in FMD was similar after IR+RIC and IR+ sham (Fig 1). In the FH group with LDL &lt;2.5 mmol/L, the decrease in FMD induced by IR was attenuated by RIC (p=0.05).

Conclusion

These observations suggest that RIC, which protects from IR-induced endothelial dysfunction in healthy controls, fails to protect from IR-induced endothelial dysfunction in patients with FH and LDL-cholesterol &gt;5.5 mmol/L. The protective effect of RIC is restored after treatment of hypercholesterolemia. This finding may have bearings on the clinical efficacy of RIC in patients with ST-elevation myocardial infarction.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Heart-lung foundation

Research reactor model for isotope production based on the design of VVER-440 reactors

The following work is an attempt to develop a model research reactor based on VVER-440 technologies, primarily for the production of radioisotopes used in nuclear medicine procedures. The article describes the basic design features of the model 10 MW multipurpose VVR reactor, including the features of reactor fuel, core, and related structures. A comparative analysis of targets for maximizing 99Mo production is also presented.

Patterns of suicide in Kuwait from 2014 to 2018

OBJECTIVES

Suicide is a public health problem in many countries around the world and is one of the top ten causes of death internationally. We performed a retrospective study from 2014 to 2018 to study the patterns of suicide in Kuwait.

STUDY DESIGN

After reviewing files from the General department of Criminal Evidence, we collected a total of 297 in our study period that were signed out as suicide fatalities.

METHODS

The relationship between demographic factors (e.g. age, sex, residential area) and suicides were studied using various statistical methodologies.

RESULTS

The majority of the 297 samples were in the age range of 19-35 years (180; 60.6%) and 36-65 years (107; 36%). Males constituted the majority of cases (241; 81.1%). The sample consisted of 20 different nationalities. More than half of the 297 samples were Indian (179; 60.2%), whereas Kuwaitis were a minority (22; 7.4%). Hanging was the preferred method of suicide in our study population (269; 90.6%). The governorate of Ahmadi had the highest death toll (89; 30%), followed by Farwaniyah (77; 25.9%) and Jahra (64; 21.5%).

CONCLUSION

The government of the State of Kuwait needs to target the group that has the largest number of fatalities by increasing education and awareness of employers and employees to the danger of this condition and the driving factors that lead people to it.

P6299Dietary nitrate restores cardiac ischemic tolerance in type 2 diabetic mice and protects against ischemia-reperfusion injury via soluble guanylate cyclase in red blood cells

Background

Inorganic nitrate has been shown to exert beneficial cardiovascular effects, which are thought to be mediated via sequential reduction of nitrate to nitrite and nitric oxide (NO). We have previously reported that hearts from type 2 diabetic db/db mice have impaired cardiac ischemic tolerance and that this effect involves reduced export of NO-like bioactivity from red blood cells (RBCs). It remains unknown whether nitrate supplementation may affect cardiac ischemic tolerance in diabetes through interference with RBC function.

Purpose

To test the hypothesis that dietary nitrate supplementation improves cardiac ischemic tolerance of hearts via an effect mediated through RBCs in type 2 diabetes.

Methods

Type 2 diabetic (db/db) and wild type (WT) mice on nitrate-free chow were treated with vehicle or nitrate (1 mM) in the drinking water for 4 weeks. Hearts were isolated and perfused using the Langendorff technique. After 30 min stabilization, the hearts were subjected to 40 min global ischemia followed by 60 min reperfusion. In protocol 1, isolated hearts from db/db and WT mice given vehicle or nitrate were perfused with buffer. In protocol 2, only hearts from untreated WT mice were used. Washed RBCs from WT or db/db mice treated with vehicle or nitrate were administered to WT hearts at the onset of ischemia with and without the soluble guanylyl cyclase (sGC) inhibitor (1H-[1,2,4] Oxadiazolo[4,3-a]quinoxalin-1-one, ODQ). In both protocols post-ischemic recovery of cardiac function was evaluated by determination of left ventricular developed pressure (LVDP).

Results

In Protocol 1, post-ischemic recovery of LVDP was impaired in hearts from db/db mice in comparison with hearts from WT mice (Fig. A). Dietary nitrate restored the ischemic tolerance of hearts from db/db mice but did not affect post-ischemic recovery of hearts from WT mice (Fig. A). In Protocol 2, administration of RBCs collected from vehicle-treated db/db mice significantly impaired post-ischemic recovery of hearts from WT mice (Fig. B). Notably, administration of RBCs from nitrate-treated db/db mice completely reversed the impairment of post-ischemic cardiac function induced by diabetic RBCs (Fig. B). Interestingly, post-ischemic cardiac function did not differ between hearts given RBCs from nitrate-treated db/db and WT mice (Fig. B). The protective effect of RBCs from nitrate-treated mice was abolished by pre-incubation of the RBCs with ODQ, an inhibitor of soluble guanylate cyclase (sGC) (Fig. C). By contrast, pretreatment of isolated WT hearts with ODQ failed to block the protective effect of RBCs from nitrate-treated mice (Fig C) indicating that sGC in the RBC but not in the heart is critical for nitrate-induced cardiac protection.

Conclusion

Dietary nitrate restores cardiac ischemic tolerance in db/db mice and protects the heart against ischemia–reperfusion injury via an RBC NO-sGC pathway.

Arginase inhibition improves endothelial function in patients with type 2 diabetes mellitus despite intensive glucose-lowering therapy

BACKGROUND

Arginase is implicated in the pathogenesis behind endothelial dysfunction in type 2 diabetes mellitus (T2DM) by its inhibition of nitric oxide formation. Strict glycaemic control is not sufficient to improve endothelial function or cardiovascular outcomes in patients with T2DM, thus other treatment strategies are needed. We hypothesized that arginase inhibition improves endothelial function beyond glucose-lowering therapy following glucose optimization in patients with poorly controlled T2DM.

METHODS AND RESULTS

Endothelial function was evaluated in 16 patients with poorly controlled T2DM (visit 1) and 16 age-matched controls using venous occlusion plethysmography. T2DM patients were re-evaluated (visit 2) after intensive glucose-lowering regimen. Endothelium-dependent (EDV) and -independent (EIDV) vasodilatations were evaluated before and after 120 min intra-arterial infusion of the arginase inhibitor N(ω)-hydroxy-nor-L-arginine (nor-NOHA). HbA1c was reduced from 87 ± 17 (visit 1) to 65 ± 11 mmol mol^-1 (visit 2, P < 0.001). Basal EDV, but not EIDV, was significantly lower in patients with T2DM than in healthy subjects (P < 0.05). EDV and EIDV were unaffected by glucose-lowering regimen in patients with T2DM. Arginase inhibition enhanced EDV in T2DM patients both at visit 1 and visit 2 (P < 0.01). There was no difference in improvement in EDV between the two occasions. EIDV was unaltered by nor-NOHA in T2DM at visit 1, but was slightly improved at visit 2.

CONCLUSIONS

Arginase inhibition improves endothelial function in patients with poorly controlled T2DM, which is maintained following glucose optimization. Thus, arginase inhibition is a promising therapeutic target beyond glucose lowering for improving endothelial function in T2DM patients.

Vagal nerve stimulation reduces infarct size via a mechanism involving the alpha-7 nicotinic acetylcholine receptor and downregulation of cardiac and vascular arginase

AIMS

Vagal nerve stimulation (VNS) protects from myocardial and vascular injury following myocardial ischaemia and reperfusion (IR) via a mechanism involving activation of alpha-7 nicotinic acetylcholine receptor (α7 nAChR) and reduced inflammation. Arginase is involved in development of myocardial IR injury driven by inflammatory mediators. The aim of the study was to clarify whether VNS downregulates myocardial and vascular arginase via a mechanism involving activation of α7 nAChR following myocardial IR.

METHODS

Anaesthetized rats were randomized to (i) sham-operated, (ii) control IR (30-min ischaemia and 2-h reperfusion, (iii) VNS throughout IR, (iv) the arginase inhibitor nor-NOHA+IR, (v) nor-NOHA+VNS+IR, (vi) selective α7 nAChR blockade by methyllycaconitine (MLA) followed by VNS throughout IR and (vii) MLA+IR.

RESULTS

Infarct size was reduced by VNS compared to control IR (41 ± 3% vs. 67 ± 2% of the myocardium at risk, P < 0.001). Myocardial IR increased myocardial and aortic arginase activity 1.7- and 3.1-fold respectively (P < 0.05). VNS attenuated the increase in arginase activity compared to control IR both in the myocardium and aorta (P < 0.05). MLA partially abolished the cardioprotective effect of VNS and completely abrogated the effect of VNS on arginase activity. Arginase inhibition combined with VNS did not further reduce infarct size.

CONCLUSION

Vagal nerve stimulation reduced infarct size and reversed the upregulation of arginase induced by IR both in the myocardium and aorta via a mechanism depending on α7 nAChR activation. The data suggest that the cardioprotective effect of VNS is mediated via reduction in arginase activity.

Abstract P3-07-21: Cytotoxic potential of the RG7388 MDM2-p53 binding antagonist and the GSK2830371 WIP1 inhibitor on MX-1 and MCF-7 human breast cancer cells

Background

The tumor suppressor p53 is a central hub in molecular signaling pathways that control the integrity of the human genome. The p53 protein functions as a transcription factor and increases the expression of many cellular genes which contribute to activation of cell cycle arrest, apoptosis and DNA repair. MDM2 is another important p53 target gene, and the MDM2 protein is capable of binding directly to p53 and directing it for degradation through the ubiquitin-dependent proteolytic pathway. Inhibition of MDM2 stabilizes p53 and MDM2 inhibitors are being explored clinically as therapies. Stabilization alone may not be enough to increase the activity of p53, and posttranslational modification of p53 by phosphorylation has been proposed to be an important contributory mechanism by which p53 becomes functionally active. Therefore maintaining the phosphorylated status of p53 in tumor cells may help to enhance its growth inhibitory and pro-apoptotic role. Wild type p53 – induced phosphatase (Wip1) is a serine – threonine phosphatase which dephosphorylates central players in the DNA damage response, including p53 and may be an additional target to enhance p53-dependent treatments. Therefore this work was focused on the effect of MDM2 (RG7388) and Wip1 (GSK2830371) inhibitors on MX-1 and MCF breast carcinoma cell lines. These two cell lines were recorded to have wild type TP53 status as well as high expression of Wip1.

Trial design

RG7388 and GSK2830371 were tested for growth inhibition on MX-1 and MCF-7 breast cancer cell lines using the sulforhodamine B (SRB) assay. The results were further confirmed and mechanism explored by western blotting using extracted protein from drug treated cell lines. Contradictory evidence regarding the TP53 mutation status of the MX-1 cell line was clarified by direct sequencing of MX-1 DNA.

Results

The MCF-7 cells responded to both RG7388 and GSK2830371 with GI50 value of 0.034 µM and 2.92 µM respectively. The MX-1 cells did not respond to either drug. The results of western blotting showed there was no expression of p53 in the MX-1 cell line. Failure to respond to RG7388and also no expression of p53 in western blotting made us suspicious about the TP53 status of the MX-1 cells. The direct sequencing results confirmed that there was a 5bp deletion in exon 4 of the TP53 gene of the MX-1 cells. The c.154_158delCAATG mutation creates a stop codon at the 54th aminoacid position and results in a truncated p53 protein (p.Gln52Valfs*3).

Conclusion

RG7388 and GSK2838371 showed cytotoxic effects on MCF-7 cells, whereas both RG7388 and GSK2838371 had no effect on the MX-1 cell line due to the truncated p53 and loss of p53 function. In conclusion, the potency of both drugs depends on the TP53 mutation status and they are likely to be mediated via p53-dependent growth inhibition and apoptosis. Further studies are needed to evaluate the combination effect of both drugs on TP53 wild type cell lines.

Citation Format: Manoharan V, Lunec J, Esfandiari A, Mahdi A, Wu C-E, Zanjirband M, Karunanayake EH, Tennekoon KH, De Silva S. Cytotoxic potential of the RG7388 MDM2-p53 binding antagonist and the GSK2830371 WIP1 inhibitor on MX-1 and MCF-7 human breast cancer cells [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-21.

A model for generating synthetic arterial blood pressure

A new model capable of simulating many important aspects of human arterial blood pressure (ABP) is proposed. Both data-driven approach and physiological principles have been applied to describe the time series of diastolic, systolic, dicrotic notch and dicrotic peak pressure points. Major static and dynamic features of the model can be prescribed by the user, including heart rate, mean systolic and diastolic pressure, and the corresponding physiological control quantities, such as baroreflex sensitivity coefficient and Windkessel time constant. A realistic ABP generator can be used to compile a virtual database of signals reflecting individuals with different clinical conditions and signals containing common artefacts. The ABP model permits to create a platform to assess a wide range of biomedical signal processing approaches and be used in conjunction with, e.g. Kalman filters to improve the quality of ABP signals.

Antibiotic resistance of Campylobacter jejuni and Campylobacter coli isolated from hog, beef, and chicken carcass samples from provincially inspected abattoirs in Ontario

Campylobacterjejuni is one of the most common causes of bacterial foodborne infection in the United States, and there are reports of resistance of Campylobacter spp. to antimicrobial agents used for the treatment of gastroenteritis. The purpose of this study was to determine the antimicrobial resistance patterns of Campylobacter spp. isolated from hog, beef, and chicken carcasses from provincially inspected abattoirs in Ontario. The agar dilution method was performed to measure antimicrobial resistance of the isolates. Antimicrobial resistance of Campylobacter isolates from hogs (n = 401), beef (n = 21), and chicken (n = 435) to ampicillin, azithromycin, chloramphenicol, ciprofloxacin, clindamycin, erythromycin, gentamicin, nalidixic acid, streptomycin, and tetracycline was determined. Resistance of chicken, hog, and beef isolates was 14.3, 18.2, and 9.5% to ampicillin; 17.9, 67.3, and 38.1% to azithromycin; 0, 0.5, and 0% to chloramphenicol; 3.7, 1.2, and 0% to ciprofloxacin; 2.3, 46.6, and 4.8% to clindamycin; 6.7, 43.6, and 4.8% to erythromycin; 0.2, 0, and 0% to gentamicin; 5.1, 10.7, and 0% to nalidixic acid; 13.6, 57.4, and 4.8% to streptomycin; and 52.6, 44.1, 42.9% to tetracycline, respectively. The hog isolates had the greatest resistance to seven of the ten antimicrobials tested. Results of this study confirm the existence of antimicrobial resistance of Campylobacter to various antimicrobial agents,especially ciprofloxacin and erythromycin, commonly used for treatment of campylobacteriosis in humans.

Antibiotic resistance of Salmonella isolated from hog, beef, and chicken carcass samples from provincially inspected abattoirs in Ontario

The emergence of antimicrobial-resistant Salmonella organisms, especially Salmonella Typhimurium DT104, has been reported in many countries, including the United States and Canada. The purposes of this study were to determine the antimicrobial resistance patterns of Salmonella isolated from hog, beef, and chicken carcasses from provincially inspected abattoirs in Ontario and to determine the agreement between the agar dilution method and the microbroth dilution method for measurement of antimicrobial resistance of the isolates. Antimicrobial resistance of Salmonella isolates from hogs (n = 71), beef (n = 24), and chicken (n = 295) to amikacin, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole, and tetracycline was determined using the two methods. None of the 390 isolates were resistant to ciprofloxacin at levels of 0.125 microg/ml. All chicken and hog isolates were sensitive to amikacin, whereas all beef isolates were sensitive to both amikacin and gentamicin. Multiple antimicrobial resistance (resistance to more than one antimicrobial) was found in 29% of bovine isolates and 42% of porcine isolates using both methods for testing and in 42% by the agar dilution and 33% by the microbroth dilution methods in the chicken isolates. Overall, there was good agreement between the two test methods for resistance to most of the antimicrobials, with disagreement found in the results in 1.3% of the isolates for ampicillin and sulfamethoxazole, 8.2% for streptomycin, 5.6% for cephalothin, and 1.0% of the isolates for tetracycline. The lack of agreement between the two test methods was found mostly among the chicken isolates.

The effects of static 3.0 T and 0.5 T magnetic fields and the echo-planar imaging experiment at 0.5 T on E. coli

Various mutant strains of Escherichia coli have been exposed to a homogeneous static magnetic field of either 0.5 T or 3.0 T and to the time varying magnetic fields found in echo-planar imaging experiments. No evidence of increased DNA damage was detected, even with bacterial strains disabled for DNA repair.

[Fructose malabsorption and dysfunctional gastrointestinal manifestations]

BACKGROUND

Individuals with impaired intestinal absorption of fructose may exhibit recurrent abdominal discomfort after the ingestion of fructose-containing foods. We report on patients with this disorder in whom the diagnosis was made by the fructose hydrogen breath test.

METHODS

We investigated 293 patients with recurrent abdominal pain, meteorism or diarrhea in connection with the ingestion of fruits, apple juice or soft drinks. Mixed expired air was collected before and at 30 minute intervals after a fructose load and analysed thereafter by a hydrogen sensitive electrochemical cell. Incomplete absorption of fructose was defined as a peak rise in breath hydrogen of > 20 ppm.

RESULTS

108 out of 293 patients showed an abnormal peak rise after fructose (mean 71.8 ppm, SD 31.4). This malabsorption of fructose was associated with clinical symptoms in 79 of them. Sensitivity and specificity of the fructose hydrogen breath test were 98 or 86 per cent respectively. 19 patients with an abnormal breath test and symptoms following fructose were reexamined after a load with equimolar concentrations of glucose and fructose. Hydrogen breath test was normal in all of them, none developed abdominal discomfort.

CONCLUSION

A considerable number of individuals suffer from dysfunctional gastrointestinal problems due to fructose malabsorption. The fructose hydrogen breath test is a simple, sensitive and noninvasive method for the diagnosis for this disorder. Possible means of treatment are dietary fructose restriction or a modification of the diet in which fructose-containing foods are exchanged for those with equal concentrations of glucose and fructose.