Retinal vascular dynamics: A window for observing an irregular heartbeat. A case report.

OBJECTIVE: We aimed to characterize several aspects of retinal vascular dynamics in a patient with arrythmia in order to elicit additional diagnostic information on microvascular dysfunction. METHODS: A 68-year-old male patient with arrythmia and an age- and gender-matched control subject underwent ocular examination including dynamic retinal vessel assessment with flicker light provocation. Retinal vessel diameters were measured continuously following a standard protocol (IMEDOS Systems, Jena, Germany). The data were evaluated using methods of signal analysis. RESULTS: Retinal vessel response following flicker provocation as well as local structural and functional behavior of retinal vessels were comparable between both individuals. The arrhythmia case demonstrated irregular arterial and venous heart rate (HR) pulsation with an average frequency of 1 Hz. Moreover, the case showed a higher magnitude and larger periods of low-frequency retinal vessel oscillations as well as lower periodicity of both HR pulsations and low-frequency vasomotions. CONCLUSIONS: Besides numerical examination of irregular HR pulsations in case of arrhythmia, from the direct noninvasive assessment of retinal vessel dynamics one can derive more detailed information on microvascular function including the whole spectrum of retinal arterial and venous pulsations and vasomotions. This may have implications for health screening not limited to atrial fibrillation.

British Journal of Biomedical Science in 2017: What have we learned?

In 2017 the British Journal of Biomedical Science published 35 articles in the various disciplines that comprise biomedical science. These were 6 reviews, 22 original articles, 6 'In Brief' short reports and one guideline. Of these, the majority were in clinical chemistry (one review, six data papers), microbiology (one review, four data papers), cellular pathology (four data papers) and virology (one review, two data papers). There were two data papers in transfusion science, whilst haematology, cytopathology and immunology were each represented by one review and one data paper. Reflecting the increasing complexity of the laboratory, five data papers crossed barriers between traditional disciplines, and so may be described as multidisciplinary. The present report will summarise key aspects of these publications.

Relationship between renal function and circulating microparticles, soluble P-selectin and E-selectin levels in atrial fibrillation.

Atrial fibrillation (AF) and chronic kidney disease are closely related, and any associated risk of stroke and thromboembolism due to AF is increased by concurrent renal dysfunction. The mechanism(s) for this include abnormalities in platelets and endothelial cells. We hypothesized relationships between levels of circulating platelet microparticles (PMPs, defined by CD42b), soluble P selectin (both reflecting platelet activation), soluble E-selectin (reflecting endothelial activation) and endothelial/platelet microparticles (EPMPs, defined by CD31) with progressive renal dysfunction. Blood samples were obtained from 160 anticoagulated AF patients. Microparticles were measured by flow cytometry, soluble E and P selectin levels by ELISA. Renal function was determined by estimated glomerular filtration rate (eGFR). EPMP levels demonstrated a linear increased trend across quartiles of eGFR (p = 0.034) and CKD stage (p < 0.001), and correlated with eGFR and serum creatinine (p < 0.01). PMPs, P-selectin and E-selectin levels were not significantly different across groupings of renal dysfunction, and no significant correlations with eGFR were evident (p = 0.186, p = 0.561, p = 0.746 respectively). Stepwise multivariable regression analysis demonstrated that worsening renal function was an independent predictor of EPMP levels (p < 0.001). In well-anticoagulated AF patients, there is potential relationship between endothelial function (as judged by elevated EPMP levels, with no change in PMPs) and renal function. Other markers of prothombotic state or cellular activation (PMP, P-selectin and E-selectin levels) were not significantly different across the various degree of renal dysfunction. Renal function must be addressed when measuring EPMP levels.

British Journal of Biomedical Science in 2016. What have we learned?

In 2016, the British Journal of Biomedical Science published 36 reports outlining specific advances in each of the various disciplines within biomedical science. These were one review, 25 original articles, 9 'In Brief' reports and one letter to the Editor. Of these, the majority were in blood science (5 in biochemistry, 7 in haematology and 2 in immunology) and infection science (8 in microbiology, 2 in virology) with a smaller number in cellular sciences (6 in cellular pathology and 2 in cytopathology). Three reports considered both biochemistry and immunology, while another reported an advance in the identification of chromosomal abnormalities. The present report will summarise key aspects of these publications that are of greatest relevance to laboratory scientists.

Modelling projections for the uptake of edoxaban in an European population to 2050: effects on stroke, thromboembolism, and health economics perspectives.

AIMS: In the coming decades, the number of Europeans with atrial fibrillation (AF) is set to rise as the population ages, and so with it will the number of strokes. The risk of thromboembolism (principally stroke and systemic embolism) and death can be reduced by the use of the vitamin K antagonists (VKA, e.g. warfarin) and more so by non-VKA oral anticoagulants (NOACs) such as edoxaban. METHODS AND RESULTS: We modelled the effect of the increasing use of edoxaban in preference to warfarin in a European AF population from both clinical and economic perspectives. We estimate that the introduction of NOACs in 2010 eliminated over 88 000 thromboembolisms and deaths annually, of which over 17 000 were ischaemic strokes. At a 1-year cost of €30k per ischaemic stroke, this strategy saved €510 million annually. Should the use of edoxaban increase from 11% in 2013 to 75% by 2030, we expect that rate of thromboembolism and death will fall from 5.67 to 5.42 total events per million patients per year, which will further eliminate over 12 000 of these events annually. At an inflation-adjusted 1-year cost of approximately €35k per ischaemic stroke, this will save €44.5 million each year. At a conservative rate of increase in the AF population of 2.2-fold from 2005, in 2050 there will be around 180 000 AF-related ischaemic strokes that, at an inflation-adjusted cost of around €62k per stroke, sums to €11 116 million. Should the rate of AF rise 2.6-fold from 2005, then in 2050 there will be 214 500 ischaemic strokes that will cost around €13 300 million. CONCLUSION: Our data point to a substantial increase in the human and economic cost burden of AF and so emphasize the need to reduce this burden. This may be achieved by the increased use of oral anticoagulants, particularly with the NOACs such as edoxaban.

Effects of non-vitamin K antagonist oral anticoagulants on fibrin clot and whole blood clot formation, integrity and thrombolysis in patients with atrial fibrillation.

Non-vitamin K antagonist oral anticoagulants (NOACs) are replacing warfarin and heparins in several clinical situations. With varying modes of action, the effects of NOACs on thrombus formation, integrity, and lysis is unknown. To determine whether two techniques of thrombelastography (TEG) and a micro-plate assay (MPA) provide novel data on thrombus formation, integrity and lysis in those taking a NOACs compared to warfarin and a control group taking aspirin. We assessed thrombogenesis, clot integrity and fibrinolysis in blood (TEG) and plasma (MPA) from 182 atrial fibrillation patients-50 on aspirin, 50 on warfarin, and 82 on a NOAC (17 apixaban, 19 dabigatran and 46 rivaroxaban). Eleven of 16 TEG indices and 4 of 5 MPA indices differed (p ≤ 0.01) between those on aspirin, warfarin or a NOAC. Three TEG indices and 4 MPA indices differed (p < 0.01) between the NOACs. Time to initiation of clot formation was most rapid on apixaban, then rivaroxaban and slowest on dabigatran. The rate of clot formation was most rapid on dabigatran, then apixaban, and slowest on rivaroxaban. Clot density was greatest on rivaroxaban, then apixaban, but weakest on dabigatran. The rate of clot dissolution was most rapid in apixaban, then dabigatran, and slowest on rivaroxaban. The TEG and MPA identify major differences in thrombogenesis and fibrinolysis in different NOACs. These techniques may have value in investigating the effects of these drugs on haemostasis in a clinical setting, and in identifying those in need of targeted therapy.

The rolling evolution of biomedical science as an essential tool in modern clinical practice.

The British Journal of Biomedical Science is committed to publishing high-quality original research that represents a clear advance in the practice of biomedical science, and reviews that summarise recent advances in the field of biomedical science. The overall aim of the Journal is to provide a platform for the dissemination of new and innovative information on the diagnosis and management of disease that is valuable to the practicing laboratory scientist. The Editorial that follows describes the Journal and provides a perspective of its aims and objectives.

British Journal of Biomedical Science in 2015: what have we learned?

In 2015, the British Journal of Biomedical Science published 47 reports on topics relating to the various disciplines within biomedical science. Of these, the majority were in infection science (15 in microbiology and two in virology) and blood science (seven in biochemistry, four in haematology, three in immunology and one in transplantation), with a smaller number in cellular sciences (four reports) and with one review across disciplines. The present report will summarise key aspects of these publications that are of greatest relevance to laboratory scientists.

The Number of GT(n) Repeats in the Hemeoxygenase-1 Gene Promoter is Increased in Pediatric Heart Failure but is Unrelated to Renal, Antioxidant and Anti-inflammatory Markers.

Products of hemeoxygenase (HO)-1 have anti-inflammatory and antioxidant functions. The HO-1 promoter has a variable number of GT(n) repeats: A low number (n < 23) is associated with high transcriptional activity in response to oxidative stress. We hypothesized that the frequency of GT(n) repeats in pediatric heart failure (HF) reflects plasma biomarkers of different disease processes: the soluble receptor for advance glycation end products (sRAGE, marking cellular activation), oxLDL (oxidative stress), NGAL (impaired renal function), HIF-1α (hypoxia) and hsCRP (inflammation). Sixty HF children [aged 4-14 years, 30 with HF due to idiopathic dilated cardiomyopathy (IDCM), 30 due to chronic renal failure (CRF)] were compared to 20 healthy controls (HC). Leukocyte HO-1 GT(n) repeats were determined by PCR, plasma markers by ELISA or nephelometry. The number of GT(n) repeats in the HF patients was higher than the number of repeats in the controls, with no difference between the patient groups (p < 0.001). sRAGE, oxLDL, HIF-1α, NGAL and hsCRP were higher in both HF groups compared to HC (all p < 0.01). IDCM had higher sRAGEs and HIF-1α compared to CRF patients (p < 0.01). NGAL was higher in CRF compared to IDCM (p < 0.01). None of the plasma/serum markers correlated with the number of GT(n) repeats in any group. The number of HO-1 promoter GT(n) polymorphism is increased in both IDCM and CRF children with HF, but is unrelated to plasma markers of different pathological processes. This casts doubts on the clinical value of the number of GT(n) repeats in pediatric HF.

Plasma CX3CL1 levels and long term outcomes of patients with atrial fibrillation: the West Birmingham Atrial Fibrillation Project.

BACKGROUND: There is growing evidence that chemokines are potentially important mediators of the pathogenesis of atherosclerotic disease. Major atherothrombotic complications, such as stroke and myocardial infarction, are common among atrial fibrillation (AF) patients. This increase in risk of adverse events may be predicted by a score based on the presence of certain clinical features of chronic heart failure, hypertension, age 75 years or greater, diabetes and stroke (the CHADS2 score). Our objective was to assess the prognostic value of plasma chemokines CCL2, CXCL4 and CX3CL1, and their relationship with the CHADS2 score, in AF patients. METHODS: Plasma CCL2, CXCL4 and CX3CL1 were measured in 441 patients (59% male, mean age 75 years, 12% paroxysmal, 99% on warfarin) with AF. Baseline clinical and demographic factors were used to define each subject's CHADS2 score. Patients were followed up for a mean 2.1 years, and major adverse cardiovascular and cerebrovascular events (MACCE) were sought, being the combination of cardiovascular death, acute coronary events, stroke and systemic embolism. RESULTS: Fifty-five of the AF patients suffered a MACCE (6% per year). Those in the lowest CX3CL1 quartile (≤ 0.24 ng/ml) had fewest MACCE (p = 0.02). In the Cox regression analysis, CX3CL1 levels >0.24 ng/ml (Hazard ratio 2.8, 95% CI 1.02-8.2, p = 0.045) and age (p = 0.042) were independently linked with adverse outcomes. The CX3CL1 levels rose directly with the CHADS2 risk score (p = 0.009). The addition of CX3CL1 did not significantly increased the discriminatory ability of the CHADS2 clinical factor-based risk stratification (c-index 0.60 for CHADS2 alone versus 0.67 for CHADS2 plus CX3CL1 >0.24 ng/ml, p = 0.1). Aspirin use was associated with lower levels of CX3CL1 (p = 0.0002) and diabetes with higher levels (p = 0.031). There was no association between CXCL4 and CCL2 plasma levels and outcomes. CONCLUSION: There is an independent association between low plasma CX3CL1 levels and low risk of major cardiovascular events in AF patients, as well as a linear association between CX3CL1 plasma levels and CHADS2-defined cardiovascular risk. The potential for CX3CL1 in refining risk stratification in AF patients merits consideration.

Why do we test for urea electrolytes?

Urea and electrolytes are the most commonly requested biochemistry tests. They provide essential information on renal function, principally in excretion and homoeostasis. Creatinine levels are a major factor in determining the estimated glomerular filtration rate, which is the gold standard marker of kidney health. The tests' clinical value is in the diagnosis and management of acute kidney injury and chronic kidney disease, which, if left untreated, can lead to thrombosis and cardiovascular disease such as myocardial infarction and stroke.

Blood tests and age-related changes in older people.

Many age-related changes in health can be detected in blood tests. In particular, renal function deteriorates with age, and this is factored in when estimating the glomerular filtration rate. However, some symptoms may be wrongly attributed to old age, while some medication can mask, exacerbate or cause problems in older people. This article looks at specific areas of pathology to help practitioners use blood tests to understand, recognise and treat diseases in older patients.

Functions and diseases of red and white blood cells.

Red and white blood cells have two main functions: the carriage of oxygen; and defence against microbial attack. The full blood count is one of the most frequently requested routine blood tests; it provides key indices such as haemoglobin and the number of white cell subsets, and provides information to aid diagnosis of a range of conditions, including anaemia, infection, leukaemia, myeloma and lymphoma.

What is the purpose of liver function tests?

The liver is the body's largest single discrete organ. It has four major functions: metabolism and synthesis; excretion; storage; and the detoxification of potential poisons. These diverse functions mean that a single test does not give enough information to assess fully how the liver is functioning; at least five different liver function tests are required. This article, part 2 in a four-part series, discusses the information on acute and chronic liver disease that these tests can provide, and how disease affects liver function.

Vascular and platelet responses to aspirin in patients with coronary artery disease.

BACKGROUND: Variability in the response to aspirin (sometimes known as aspirin resistance) in modulating platelet activity is a potentially important clinical issue in coronary artery disease (CAD), but may be also be important in other areas of pathophysiology. MATERIALS AND METHODS: Testing the hypothesis of a relationship between aspirin resistance and vascular function, inflammation and coagulation, we recruited 175 stable CAD outpatients taking 75 mg aspirin daily. Indices were compared to 58 controls not taking aspirin. Platelet activity was assessed by light transmission aggregometry (LTA) to 0·5 mg/mL arachidonic acid (AA), plasma markers soluble P selectin and thromboxane (ELISA), and resting and AA stimulated membrane P selectin and PAC-1 expression (flow cytometry). Vascular function was assessed by arterial stiffness (Sphygmocor system), von Willebrand factor and soluble E selectin (ELISA), inflammation by high sensitivity CRP and interleukin-6, and coagulation by tissue factor and fibrin d-dimers levels (all immunoassay). RESULTS: The 5-min LTA response AA was superior to flow cytometry in discriminating the response of platelets to aspirin. Using the cut-off of 20% LTA response to AA, 32·6% of patients were aspirin resistant. The latter had higher soluble P selectin (P = 0·03), CRP (P = 0·029) and fibrin d-dimers (P = 0·01) compared to those who were aspirin sensitive. There was no relationship between aspirin response status and any vascular index. CONCLUSION: We conclude that LTA is a more sensitive marker of aspirin resistance than is flow cytometry for P-selectin and PCA-1, and that aspirin response has no influence on vascular function.

The effect of statin therapy withdrawal on monocyte subsets.

BACKGROUND: Three functionally distinct monocyte subsets have been identified. Statins are of undoubted effect in atherosclerosis and have numerous pleiotropic effects that contribute to their clinical success, but the effect of these drugs on monocyte subsets is unclear. We hypothesised a beneficial effect of statins on key receptor expression by monocyte subsets. MATERIAL AND METHODS: Effects of temporal (2 weeks) cessation of statin therapy by 66 patients with stable coronary artery disease on monocyte subsets [CD14++CD16-CCR2+ (Mon1), CD14++CD16+CCR2+ (Mon2) and CD14+CD16++CCR2- (Mon3)], their aggregates with platelets and their expression of a number of receptors involved in inflammation (IL-6 receptor), adhesion [vascular cell adhesion molecule (VCAM)], angiogenesis [vascular endothelial growth factor (VEGF)] and repair were assessed by flow cytometry. RESULTS: Statin cessation did not lead to any significant changes in absolute numbers of monocyte subsets or the degree of their aggregation with platelets. All monocyte subsets showed significant downregulation of expression of vascular endothelial factor receptor 2, Tie2 and Toll-like receptor-4 (TLR4; all changes P < 0·01). Expression of CXCR4 was only reduced in Mon1 cells (P = 0·013). There was no significant change in the expression of CD14, CD16, CCR4, IL6 receptor and VCAM (all P = NS). CONCLUSIONS: Statin withdrawal does not affect counts of any of monocyte subsets, but leads to downregulation of expression of TLR4 and receptors related to angiogenesis on all subsets, as well as a decrease in density of CXCR4 expression on 'classical' Mon1. These data provide further support of pleiotropic effects of statins and their effects on monocyte pro-angiogenic and proreparative characteristics.

Angiogenin outperforms VEGF, EPCs and CECs in predicting Dukes' and AJCC stage in colorectal cancer.

BACKGROUND: Circulating endothelial cells (CECs), endothelial progenitor cells (EPCs), Willebrand factor (vWf), soluble E-selectin, vascular endothelial growth factor (VEGF) and angiogenin are of interest in cancer vascular biology. However, few studies have looked at more than one in combination. We set out to determine which would be best in predicting the Dukes' and American Joint Committee on Cancer (AJCC) scores in colorectal cancer patients. METHODS: We recruited 154 patients with colorectal cancer, 29 healthy controls and 26 patients with benign bowel disease. CD34(+) /CD45(-) /CD146(+) CECs and CD34(+) /CD45(-) /CD309[KDR](+) EPCs were measured by flow cytometry, plasma markers by ELISA. RESULTS: All research indices were raised in colorectal cancer (P < 0·05) compared to control groups. Although CECs (P < 0·05), EPCs (P < 0·01) and angiogenin (P < 0·01) increased stepwise across the four Dukes' stages and four AJCC stages, only angiogenin remained significant in multiple regression analysis (P = 0·003 for Dukes, P = 0·01 for AJCC). Angiogenin levels were higher in Dukes' stages C and D compared to stage A, and AJCC stages 4-6 and 7-10 compared to stage 1 (all P < 0·05). Adding a second research marker to angiogenin did not markedly improve this relationship. CONCLUSION: Although we found disturbances in endotheliod cells and plasma markers of the endothelium and growth factors, only angiogenin levels were independently associated with progression of the Dukes' stage and AJCC stage, with the association with Duke's stage being stronger. We suggest that angiogenin is a potential biomarker in risk stratification for colorectal cancer, and may aid clinical decision making.

The effect of melatonin on plasma markers of inflammation and on expression of nuclear factor-kappa beta in acetic acid-induced colitis in the rat.

BACKGROUND AND AIMS: Melatonin may be involved in gastrointestinal tract physiology and could affect inflammation-related gastrointestinal disorders. Rat models of ulcerative colitis imply melatonin is beneficial. To determine potential pathophysiological mechanisms, we assessed colonic nuclear factor-kappa beta expression and measured serum levels of pentraxin-3, lipid peroxides, and total thiols in an acetic acid model of this disease. MATERIALS AND METHODS: Thirty rats were divided into five groups: a control group, an acetic acid-induced colitis group, a group treated with melatonin before colitis induction, a group treated short-term after colitis induction, and a group treated long-term after colitis induction. After four weeks, blood samples were taken for measurement of pentraxin-3, lipid peroxide, and total thiols. Sections of the colon were taken for histopathological examination and immunohistochemical detection of nuclear factor-kappa beta expression. RESULTS: Melatonin administration reduced nuclear factor-kappa beta immunohistochemical expression, reduced serum levels of lipid peroxide and pentraxin-3, and maintained serum levels of total thiols. However, in long-term treatment the protective effect of melatonin was not as marked. CONCLUSION: Melatonin is effective in prevention and short-term treatment of the inflammatory process in acetic-acid induced colitis whereas the benefit of long-term treatment is unclear. Benefit may be linked to protection mechanisms against inflammatory processes by inhibiting the nuclear factor-kappa beta and conserving endogenous antioxidant reserves of total thiols, thus reducing the level of colonic damage possibly caused by lipid peroxides.

An observational study of endothelial function in early arthritis.

BACKGROUND: Endothelial dysfunction is present in established rheumatoid arthritis, but it is not clear at what stage of the disease this abnormality develops. We set out to determine whether endothelial damage/dysfunction is present in a group of patients with early arthritis (EA) (new onset inflammatory arthritis, EA). MATERIALS AND METHODS: Eighteen patients with EA, 48 healthy controls and 25 disease controls were recruited. Plasma was obtained for endothelial [von Willebrand factor (vWF) and soluble E-selectin] and angiogenesis markers (vascular endothelial growth factor and its receptor sFlt-1), adhesion molecules (intercellular adhesion molecule 1 and vascular cell adhesion molecule 1) and circulating endothelial cells (CECs, as a marker of endothelial damage). Microvascular endothelial function was assessed using laser Doppler perfusion imaging and macrovascular function using flow-mediated dilatation of the brachial artery. RESULTS: von Willebrand factor and CECs (both P < 0.05) were significantly elevated in EA suggesting endothelial dysfunction and damage but were unrelated to classical laboratory markers of inflammation C-reactive protein, erythrocyte sedimentation rate or IL6. No other biomarkers was elevated in EA. Microvascular and macrovascular abnormalities were confined to endothelium-independent (smooth muscle cell) responses. CONCLUSIONS: Endothelial damage/dysfunction is present early in the course of inflammatory arthritis but is not directly related to inflammation markers.

Blood and hair lead in children with different extents of iron deficiency in Karachi.

Childhood iron deficiency has a high incidence in Pakistan. Some but not all studies have shown that dietary iron deficiency may cause increased absorption of lead as both compete for the same transporters in the small intestine. Therefore, children in Pakistan, residing in heavily polluted cities like Karachi may be prone to lead poisoning. This hypothesis was tested by investigating blood and hair lead concentrations in children from Karachi who were divided into four groups of iron status; normal, borderline iron deficiency, iron deficiency and iron deficiency anaemia. A prospective observational study was conducted where 269 children were categorized into four groups of iron status using the World Health Organization criteria and one based on soluble transferrin receptor measurements. Blood iron status was determined using a full blood count, serum iron, ferritin, transferrin saturation and soluble transferrin receptor measurements. Blood lead was determined by graphite atomic absorption spectroscopy, whereas hair lead was assessed using an inductively coupled plasma atomic emission spectroscopy technique. Blood lead concentrations were significantly higher in children with iron deficiency anaemia (mean [95% confidence intervals] were 24.9 [22.6-27.2] µg/dL) compared to those with normal iron status (19.1 [16.8-21.4] µg/dL) using WHO criteria. In contrast, hair lead content was not significantly different in children of different iron status. Our findings reinforce the importance of not only reducing environmental lead pollution but also the development of national health strategies to reduce childhood iron deficiency in Pakistan.