Methods to study xenografted human cancer in genetically diverse mice.

Xenografting human cancer tissues into mice to test new cures against cancers is critical for understanding and treating the disease. However, only a few inbred strains of mice are used to study cancers, and derivatives of mainly one strain, mostly NOD/ShiLtJ, are used for therapy efficacy studies. As it has been demonstrated when human cancer cell lines or patient-derived tissues (PDX) are xenografted into mice, the neoplastic cells are human but the supporting cells that comprise the tumor (the stroma) are from the mouse. Therefore, results of studies of xenografted tissues are influenced by the host strain. We previously published that when the same neoplastic cells are xenografted into different mouse strains, the pattern of tumor growth, histology of the tumor, number of immune cells infiltrating the tumor, and types of circulating cytokines differ depending on the strain. Therefore, to better comprehend the behavior of cancer in vivo, one must xenograft multiple mouse strains. Here we describe and report a series of methods that we used to reveal the genes and proteins expressed when the same cancer cell line, MDA-MB-231, is xenografted in different hosts. First, using proteomic analysis, we show how to use the same cell line in vivo to reveal the protein changes in the neoplastic cell that help it adapt to its host. Then, we show how different hosts respond molecularly to the same cell line. We also find that using multiple strains can reveal a more suitable host than those traditionally used for a "difficult to xenograft" PDX. In addition, using complex trait genetics, we illustrate a feasible method for uncovering the alleles of the host that support tumor growth. Finally, we demonstrate that Diversity Outbred mice, the epitome of a model of mouse-strain genetic diversity, can be xenografted with human cell lines or PDX using 2-deoxy-D-glucose treatment.

Cold stress during room temperature housing alters skeletal response to simulated microgravity (hindlimb unloading) in growing female C57BL6 mice.

Laboratory mice are typically housed at temperatures below the thermoneutral zone for the species, resulting in cold stress and premature cancellous bone loss. Furthermore, mice are more dependent upon non-shivering thermogenesis to maintain body temperature during spaceflight, suggesting that microgravity-induced bone loss may be due, in part, to altered thermogenesis. Consequently, we assessed whether housing mice at room temperature modifies the skeletal response to simulated microgravity. This possibility was tested using the hindlimb unloading (HLU) model to mechanically unload femora. Humeri were also assessed as they remain weight bearing during HLU. Six-week-old female C57BL6 (B6) mice were housed at room temperature (22 °C) or near thermoneutral (32 °C) and HLU for 2 weeks. Compared to baseline, HLU resulted in cortical bone loss in femur, but the magnitude of reduction was greater in mice housed at 22 °C. Cancellous osteopenia in distal femur (metaphysis and epiphysis) was noted in HLU mice housed at both temperatures. However, bone loss occurred at 22 °C, whereas the bone deficit at 32 °C was due to failure to accrue bone. HLU resulted in cortical and cancellous bone deficits (compared to baseline) in humeri of mice housed at 22 °C. In contrast, fewer osteopenic changes were detected in mice housed at 32 °C. These findings support the hypothesis that environmental temperature alters the skeletal response to HLU in growing female mice in a bone compartment-specific manner. Taken together, species differences in thermoregulation should be taken into consideration when interpreting the skeletal response to simulated microgravity.

Genetically diverse mouse platform to xenograft cancer cells.

The lack of genetically diverse preclinical animal models in basic biology and efficacy testing has been cited as a potential cause of failure in clinical trials. We developed and characterized five diverse RAG1 null mouse strains as models that allow xenografts to grow. In these strains, we characterized the growth of breast cancer, leukemia and glioma cell lines. We found a wide range of growth characteristics that were far more dependent on strain than tumor type. For the breast cancer cell line, we characterized the spectrum of xenograft/tumor growth at structural, histological, cellular and molecular levels across each strain, and found that each strain captures unique structural components of the stroma. Furthermore, we showed that the increase in tumor-infiltrating myeloid CD45+ cells and the amount of circulating cytokine IL-6 and chemokine KC (also known as CXCL1) is associated with a higher tumor size in different strains. This resource is available to study established human xenografts, as well as difficult-to-xenograft tumors and growth of hematopoietic stems cells, and to decipher the role of myeloid cells in the development of spontaneous cancers.

Harms and Contributors of Leaving Against Medical Advice in Patients With Infective Endocarditis.

INTRODUCTION: Patients leaving against medical advice (AMA) are commonly encountered in hospital medicine. The problem is prevalent worldwide and across all fields of medicine. A retrospective study of 47,583 patients reported a 3.3% AMA rate in 2015. OBJECTIVES: In this retrospective study, we aimed (1) to study the demographic, clinical, and laboratory parameters of infective endocarditis (IE) patients leaving AMA. We also compared (2) the various risk factors and outcomes of these patients with IE patients who completed treatment. RESULTS: A total of 111 patients diagnosed with IE were recruited for 36 months. Of the 74 patients with available details, 32 patients (29%) left AMA during their treatment. The mean age of patients leaving AMA was 39, and among those who left AMA, 66% were females. As compared with patients completing therapy, patients leaving AMA tend to have higher comorbidities, including injection drug use (68.1% versus 31.9%), prior IE (83.3% versus 16.7%), and chronic hepatitis C (72.4% versus 27.8%). Rates of consumption of substances of abuse were higher among those who left AMA. Patients leaving AMA also had higher psychiatric comorbidities (63% versus 37.5%), history of leaving AMA (70.5% versus 29.5%), and consumption of more than 2 substances of abuse. Morbidity was higher in patients leaving AMA. There was a statistically significant association between the development of distal embolus ( P < 0.001), the need for recurrent admissions ( P = 0.002), recurrent bacteremia ( P < 0.001), developing new embolus ( P < 0.001), and overall morbidity ( P = 0.002) among IE patients leaving AMA. CONCLUSIONS: Infective endocarditis patients leaving AMA tend to be younger females. These patients have prior comorbidities of injection drug use, prior IE, multiple psychiatric comorbidities, drug use, and multiple socioeconomic issues. Patients leaving AMA tend to develop further non-Central nervous system embolic events, recurrent bacteremia, and require frequent admissions. Morbidity in these patients was higher.

Predictors, patterns and outcomes following Infective endocarditis and stroke.

Patients with infective endocarditis can have multiple neurological manifestations.  Cerebrovascular events (CVE) in patients with IE can be hemorrhagic or embolic.  Multiple factors are known to predispose to CVE and increased mortality in patients with IE.  In this study, we aimed to describe various outcomes among patients with IE and CVE.  We retrospectively analyzed 160 patients with definite IE.  Among these, patients with radiological evidence of CVE were included.  Clinical, radiological, echocardiographic details were obtained.  Outcome studied were the requirement of intensive care unit care, the requirement of mechanical ventilation, prolonged course of antibiotics, prolonged duration of hospital stay, the requirement of surgical intervention, and mortality.  In this study, 16 [10%] of patients with IE were identified to have a CVE.  The mean age of the patients was 55, and 87.5% of them were male.  25% of patients had prior IE.  IE involving left-sided valves were predominant, with the involvement of mitral valve reported in 62.5% of patients.  More than half of the patient's had details of magnetic resonance imaging (MRI) of the brain.  CVE were mostly ischemic, anterior circulation predominant, multiple, and bilateral.  In patients with IE and CVE morbidity including the requirement of ICU care, prolonged antibiotics course, and the requirement of surgical intervention contributed to increased duration of hospital stay.  In conclusion, CVE in patients with IE tends to present as multiple infarcts predominantly located over anterior circulation.  IE patients with CVE tend to have higher morbidity and mortality.

Quantifying and reporting cardiac findings in imaging of COVID-19 patients.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection continues to be a public health emergency and a pandemic of international concern. As of April 31st,  the reported cases of COVID-19 are three million in 186 countries. Reported case fatality has crossed 200 thousand among which more than fifty thousand has been in the USA. Most patients present with symptoms of fever, cough, and shortness of breath following exposure to other COVID-19 patients. Respiratory manifestations predominate in patients with mild, moderate, severe illness. Imaging of patients with COVID-19 consistently reports various pulmonary parenchymal involvement. In this article we wanted to reinforce and review the various reported imaging patterns of cardiac and mediastinal involvement in COVID-19 patients. Among patients with COVID 19 who underwent various imaging of chest various cardiac findings including pericardial effusion, myocarditis, cardiomegaly has been reported. Most of these findings have been consistently reported in patients with significant acute myocardial injury, and fulminant myocarditis. Acute biventricular dysfunction has also been reported with subsequent improvement of the same following clinical improvement. Details of cardiac MRI is rather limited. In a patient with clinical presentation of acute myocarditis, biventricular myocardial interstitial edema, diffuse biventricular hypokinesia, increased ventricular wall thickness, and severe LV dysfunction has been reported. Among patients with significant clinical improvement in LV structure and function has also been documented. With increasing number of clinical cases, future imaging studies will be instrumental in identifying the various cardiac manifestations, and their relation to clinical outcome.

Loss of TRP53 (p53) accelerates tumorigenesis and changes the tumor spectrum of SJL/J mice.

Known as the guardian of the genome, transformation-related protein 53 (TRP53) is a well -known tumor suppressor. Here, we describe a novel TRP53 deficient mouse model on a tumor prone background-SJL/J mice. The absence of TRP53 (TRP53 nullizygosity) leads to a shift in the tumor spectrum from a non-Hodgkin's-like disease to thymic lymphomas and testicular teratomas at a very rapid tumor onset averaging ~12 weeks of age. In haplotype studies, comparing tumor prone versus tumor resistant Trp53 null mouse strains, we found that other tumor suppressor, DNA repair and/or immune system genes modulate tumor incidence in TRP53 null strains, suggesting that even a strong tumor suppressor such as TRP53 is modulated by genetic background. Due to their rapid development of tumors, the SJL/J TRP53 null mice generated here can be used as an efficient chemotherapy or immunotherapy screening mouse model.

Cerebrovascular events in COVID-19 patients.

Neurological manifestations in patients with COVID-19 are more frequently being reported. Cerebrovascular events have been reported in around 3% of patients. In this review we summarize the published literature on cerebrovascular events in patients with COVID-19 as available on the PubMed database. So far, 3 studies have reported cerebrovascular events. Cerebrovascular events were identified on screening patients with decreased consciousness or in the presence of focal neurological deficits. These events were common in elderly, critically ill patients and in patients with prior cardio-cerebrovascular comorbidities. The diagnosis of cerebrovascular events was confirmed with computed tomography of the brain in most studies reporting neurological events. Multiple pathological mechanisms have been postulated regarding the process of neurological and vascular injury among which cytokine storm is shown to correlate with mortality. Patients with severe illness are found to have a higher cardio- cerebrovascular comorbidity. With an increasing number of cases and future prospective studies, the exact mechanism by which these cerebrovascular events occur and attribute to the poor outcome will be better understood.

An Update on Pulmonary Hypertension in Coronavirus Disease-19 (COVID-19).

Coronavirus 19 disease (COVID-19) continues to be a pandemic with global implications.  Respiratory system involvement is the most common manifestation in symptomatic patients.  In this literature review, we describe the diagnosis, management, and implications of pulmonary hypertension (PH) among patients with COVID-19.  We defined pulmonary hypertension as increasing mean pulmonary artery pressure (mPAP) of ≥ 25 mm Hg at rest.  In our literature search, we identified 4 articles with details on pulmonary hypertension.  Among these, two reported various echocardiographic details for diagnosing pulmonary hypertension.  In 1 study evidence of pulmonary hypertension was noted in 13.4% of patients.  Patients with severe COVID-19 were reported to have a higher proportion of pulmonary hypertension as compared to mild COVID-19 disease [22% vs 2%].  Elevated pulmonary artery systolic pressure was significant in predicting mortality.  COVID-19 patients with chronic obstructive pulmonary disease, congestive heart failure, myocardial injury, pulmonary embolism, and prior pulmonary hypertension were at a higher risk of worsening pulmonary hypertension.  Multiple mechanisms for developing pulmonary hypertension that have been postulated are i) concomitant worsening myocardial injury, ii) cytokine storm, endothelial injury, hypercoagulability attributing to development of venous thromboembolism, iii) and the presence of thrombotic microangiopathy.  Among patients with severe COVID-19 disease and pulmonary hypertension, complications including acute respiratory distress syndrome, acute myocardial injury, the requirement of intensive care unit admission, the requirement of mechanical ventilation, and mortality are higher.

Thermoneutral housing attenuates premature cancellous bone loss in male C57BL/6J mice.

Mice are a commonly used model to investigate aging-related bone loss but, in contrast to humans, mice exhibit cancellous bone loss prior to skeletal maturity. The mechanisms mediating premature bone loss are not well established. However, our previous work in female mice suggests housing temperature is a critical factor. Premature cancellous bone loss was prevented in female C57BL/6J mice by housing the animals at thermoneutral temperature (where basal rate of energy production is at equilibrium with heat loss). In the present study, we determined if the protective effects of thermoneutral housing extend to males. Male C57BL/6J mice were housed at standard room temperature (22°C) or thermoneutral (32°C) conditions from 5 (rapidly growing) to 16 (slowly growing) weeks of age. Mice housed at room temperature exhibited reductions in cancellous bone volume fraction in distal femur metaphysis and fifth lumbar vertebra; these effects were abolished at thermoneutral conditions. Mice housed at thermoneutral temperature had higher levels of bone formation in distal femur (based on histomorphometry) and globally (serum osteocalcin), and lower global levels of bone resorption (serum C-terminal telopeptide of type I collagen) compared to mice housed at room temperature. Thermoneutral housing had no impact on bone marrow adiposity but resulted in higher abdominal white adipose tissue and serum leptin. The overall magnitude of room temperature housing-induced cancellous bone loss did not differ between male (current study) and female (published data) mice. These findings highlight housing temperature as a critical experimental variable in studies using mice of either sex to investigate aging-related changes in bone metabolism.