Environmental and occupational exposure to lead as a potential risk factor for cardiovascular disease

We have evaluated current knowledge on relations between environmental and occupational exposure to lead with a strong emphasis on cardiovascular disease risk factors, such as the influence of lead compounds on lipid disturbances and arterial blood pressure. In addition, "novel" biochemical and vascular risk factors for cardiovascular diseases were discussed, as well as the combination of lead exposure and genetic predisposition to cardiovascular diseases. Occupationally and educationally, awareness of the unfavourable effects of lead on cardiovascular diseases risk factors should be emphasised. Indeed, accurate identification of the various mechanisms that might account for the effects of lead on the cardiovascular system should be of the highest priority in this field of research.

The importance of selenium and zinc deficiency in cardiovascular disorders

Cardiovascular diseases often linked with lifestyle are among the main causes of death, especially in the elderly population. The role of trace elements in health and disease has been emphasized in multiple scientific research. Moreover, supplementation of trace elements to improve health is becoming increasingly popular. The following paper presents current views on the relationship between the concentration of trace elements such as selenium and zinc in the body, as well as morphology and function of the cardiovascular system. Research discussing the effect of selenium and zinc supplementation on the function of the heart and blood vessels was also reviewed. The relationship between selenium and zinc concentration and morphology and function of the cardiovascular system is equally unclear, and therefore there is currently no scientific evidence for its supplementation for preventing cardiovascular diseases. It seems justified to continue scientific research on this subject due to the small number of experimental studies available on the topic of selenium and zinc deficiency and their impact on the cardiovascular system.

Radiological Cardiothoracic Ratio in Evidence-Based Medicine

The cardiothoracic ratio (CTR), expressing the relationship between the size of the heart and the transverse dimension of the chest measured on a chest PA radiograph, is a commonly used parameter in the assessment of cardiomegaly with a cut-off value of 0.5. A value of >0.5 should be interpreted as enlargement of the heart. The following review describes the current state of available knowledge in terms of contentious issues, limitations and useful aspects regarding the CTR. The review was carried out on the basis of an analysis of scientific articles available in the PubMed database, searched for using the following keywords: “CTR”, “cardiothoracic ratio”, “cardiopulmonary ratio”, “cardiopulmonary index”, and “heart-lung ratio”. According to the accumulated knowledge, the CTR can still be used as an important parameter that can be easily determined in establishing enlargement of the heart. However, an increased CTR does not directly relate to heart function. In the era following the development of diagnostic methods such as computed tomography, magnetic resonance imaging, and ultrasonography, CTR modifications based on these methods are used with varying clinical usefulness. It is important to consider the definition of the CTR and remember to base measurements on PA radiographs, as attempts to mark it in other projections face many limitations.

Obstructive sleep apnea as a predictor of reduced heart rate variability

PURPOSE

This study aimed to analyze the relationship between the occurrence of obstructive sleep apnea (OSA) and heart rate variability (HRV) in a group of patients with clinical suggestion of OSA.

METHODS

104 patients with clinical suspicion of OSA were qualified to participate in the study (age: 53.15 ± 13.43 years). All participants took part in a survey and were subjected to laboratory tests, 24-hour ECG Holter monitoring, and polysomnography. The participants were divided into groups depending on the criterion of the presence of OSA.

RESULTS

The analysis of time HRV demonstrated lower parameters of SDNN for the entire recording and a 15-minute fragment of daily activity, as well as a lower pNN50 for the entire recording in those patients with diagnosed OSA. A statistically significant difference was observed for the spectral analysis of the LF/HF which was higher in the participants with OSA during the 15-minute fragment of N3 sleep. A negative correlation was observed between AHI and the following parameters: SDSD from the entire Holter recording (r = -0.21, p < 0.05) and from the 15-minute fragment of daily activity (r = -0.19, p < 0.05), mRR from the fragment of N3 sleep (r = -0.19, p < 0.05) and VLF from the entire Holter recording (r = -0.26, p < 0.05). A statistically significant positive correlation between AHI and LF/HF in 15-minute fragments of N3 sleep was found (r = 0.26, p < 0.05).

CONCLUSIONS

The study group of patients with OSA is characterized by reduced HRV. The higher AHI constitutes an independent predictor of reduced HRV, both in the sympathetic and parasympathetic components, and the sympathetic-parasympathetic balance.

The influence of hypertension on daytime sleepiness in obstructive sleep apnea

Daytime sleepiness is a common symptom among hypertensive patients. The aim of this study was to determine subjective sleepiness assessed by Epworth Sleepiness Scale (ESS) and to asses sleep architecture in 304 patients with arterial hypertension. All patients underwent a standardized diagnostic overnight, polysomnography. The control group consisted of 67 normotensives. The hypertensive patients had a decreased sleep efficiency, mean and minimum oxygen saturation levels, and increased apnea/hypopnea index and oxygen desaturation index compared with normotensive patients. The lower ratio of N3 sleep, higher of N2 sleep, and decreased sleep efficiency was observed in hypertensives without obstructive sleep apnea (OSA). In the moderate to severe OSA groups, the total ESS score was significantly lower in hypertensives compared with normotensives. The ESS scores decreased with age in hypertensives, but not in normotensives. The study showed that ESS total score is lower in hypertensives than in normotensives with OSA, making the OSA more difficult to suspect. Thus, the low ESS score in hypertensives should not discourage further evaluation.

The expression of Toll-like receptors in patients with acute myeloid leukemia treated with induction chemotherapy

Toll-like receptors play an important role in the host defense against microorganisms. TLRs are mainly expressed in human immune-related cells, such as monocytes, neutrophils, macrophages, dendritic cells, T cells, B cells and NK cells. The expression or up-regulation of TLRs has been demonstrated in some tumors and tumor cell lines but the role of TLRs in pathogenesis and development of acute leukemias remains unclear. The aim of this study was to evaluate the expression of TLR2, TLR4 and TLR9 and their significance as prognostic factors in patients with acute leukemias treated with induction chemotherapy. 103 patients with newly diagnosed acute myeloid leukemia (AML) were evaluated (47 females and 56 males). The median age of patients was 51 years. Using quantitative reverse transcriptase PCR, the mRNA expression of genes TLR2, TLR4 and TLR9 was measured. The mRNA expression of TLR2 and TLR4 was significantly higher in patients with NR than in patients with CR and CRi. We especially observed that mRNA expression of TLR2 and TLR4 was significantly higher in patients with myelomonocytic and monoblastic acute leukemia than in patients with other types of AML. The mRNA expression of TLR2 and TLR4 was higher in AML patients than in healthy individuals, although there was no statistically significant difference. Patients with higher mRNA expression of TLR2 and TLR4 had significantly shorter OS than patients with lower mRNA expression of TLR2 and TLR4. Multivariate analysis showed that mRNA expression of TLR2 and the age of patients were independent factors associated with treatment response. Our results suggest that TLRs could be an independent prognostic factor for response rate after induction therapy in patients with acute myeloid leukemias.

Relation between occupational exposure to lead, cadmium, arsenic and concentration of cystatin C

Lead, cadmium and arsenic represent well recognized toxic agents which in a specific manner disturb function of cardiovascular system. Cystatin C has been accepted to be a significant prognostic factor for cardiovascular diseases. The study aimed at defining relationship between occupational exposure to lead, cadmium and arsenic on one hand and concentration of cystatin C on the other. The studies were performed on 282 men occupationally exposed to lead, cadmium and arsenic. Among the tested individuals several groups of persons were distinguished: exposed exclusively to lead (Pb group), cadmium (Cd group), arsenic (As group), to lead and cadmium (Pb/Cd group), to lead and arsenic (Pb/As group) or to cadmium and arsenic (Cd/As group). In all the individuals serum concentration of cystatin C was estimated. Concentration of cystatin C was found to be significantly higher in Pb group than in Cd and As groups, also in Pb/Cd group higher than in Cd group and in Pb/As group than in As group. Positive linear correlations were established between Pb concentration in blood (Pb-B) and serum concentration of cystatin C (r=0.59; p<0.05) as well as between urinary concentration of As (As-U) and serum concentration of cystatin C (r=0.41; p<0.05). Regression analysis demonstrated that higher blood level of lead, higher urinary level of arsenic, more advanced age and higher body mass index represented independent risk factors of an increased serum concentration of cystatin C in the group of persons exposed to lead, cadmium and arsenic.

CONCLUSIONS

Higher blood level of lead and higher urinary level of arsenic represented independent risk factors of an increased serum concentration of cystatin C in the group of persons occupationally exposed to lead, cadmium and arsenic. Concentration of lead in blood was significantly influencing serum concentration of cystatin C. The highest mean serum concentration of cystatin C was detected in the group of foundry workers exposed simultaneously to lead and arsenic.

Clinical response to azacitidine therapy depends on microRNA-29c (miR-29c) expression in older acute myeloid leukemia (AML) patients

Acute myeloid leukemia (AML) is a heterogeneous disease with different clinical course and prognosis. microRNA-29 (miR-29) family of non-coding small RNAs can play an important role in pathogenesis of AML, but also can influence response to therapy.

The purpose of the study was to evaluate miR-29c expression in AML patients in relationship to clinical parameters and response to chemotherapy, including azacitidine.

Expression of microRNA-181 determines response to treatment with azacitidine and predicts survival in elderly patients with acute myeloid leukaemia

MicroRNAs (miRs) are small non-coding RNAs that play important roles in cell differentiation and survival. Abnormal expression of miRs has been demonstrated in numerous types of cancer, including acute myeloid leukaemia (AML). The aim of the present study was to evaluate miR-181 expression at diagnosis and following the completion of chemotherapy in AML patients, with regard to clinical response and outcome, particularly in patients treated with azacitidine. miR-181 expression was analysed using reverse transcription-quantitative polymerase chain reaction in 95 bone marrow specimens from newly diagnosed AML patients and in 20 healthy subjects for comparison. The results revealed upregulated miR-181 expression in the total cohort of AML patients, which was correlated with longer survival. However, in a subset of older AML patients treated with azacitidine, low miR-181 expression at diagnosis was a predictor for complete remission and prolonged survival. The findings indicated that miR-181 has an important role in AML and determines response to azacitidine treatment in older AML patients.

Concentration of Thyrotropic Hormone in Persons Occupationally Exposed to Lead, Cadmium and Arsenic

Thyroid hormones are essential for body homeostasis. The scientific literature contains restricted proofs for effects of environmental chemical factors on thyroid function. The present study aimed at evaluating the relationship between toxicological parameters and concentration of thyrotropic hormone in persons occupationally exposed to lead, cadmium and arsenic. The studies were conducted on 102 consecutive workers occupationally exposed to lead, cadmium and arsenic (mean age 45.08 ± 9.87 years). The estimated parameters characterizing occupational exposure to metals included blood cadmium concentration (Cd-B), blood lead concentration (Pb-B), blood zinc protoporphyrin concentration (ZnPP) and urine arsenic concentration (As-U). Thyroid function was evaluated using the parameter employed in screening studies, the blood thyrotropic hormone concentration (TSH). No differences were disclosed in mean values of toxicological parameters between the subgroup of persons occupationally exposed to lead, cadmium and arsenic with TSH in and out of the accepted normal values. Logistic regression demonstrated that higher blood total bilirubin concentrations (ORu = 4.101; p = 0.025) and higher Cd-B (ORu = 1.532; p = 0.027) represented independent risk factors of abnormal values of TSH in this group. In conclusion, in the group of workers exposed to lead, cadmium and arsenic, higher blood cadmium concentration seems to augment the risk of abnormal hormonal thyroid function.

Evaluation of the significance of cystatin C levels in patients suffering from coronary artery disease

OBJECTIVES

Cystatin C is a novel marker used in the diagnosis of preclinical chronic kidney disease (CKD). The aim of the study was to assess the role of cystatin C in the diagnosis of coronary artery disease.

MATERIAL AND METHODS

The study involved 63 patients of a mean age of 62.7 ± 9.5 years. The population was divided into two groups: Group I were patients with angiographically diagnosed coronary artery disease (CAD) with their first acute coronary syndrome (ACS, n = 45); Group II were patients who had clinically diagnosed coronary disease but were negative on angiography (n = 18). Cystatin C levels were measured before angiography in both groups; in Group I they were also measured 6 months after discharge.

RESULTS

Cystatin C levels were significantly higher in Group I (p = 0.01), and this depended on the type of CAD: non-ACS, non-ST elevated myocardial infarction (NSTEMI) or ST elevated myocardial infarction (STEMI) (p = 0.01). Cystatin C levels correlated inversely with the left ventricular ejection fraction in the whole study population (p = 0.003) and in patients with NSTEMI (p = 0.03). A high cystatin C level was found to be a risk factor for ACS (OR: 1.002 95% CI [1.00029-1.004], p = 0.02) and STEMI (OR: 1.0009 95% CI [0.99-1.002], p = 0.04) but not for NSTEMI (OR: 0.99 95% CI [0.99-1.0], p = 0.21. A ROC analysis revealed that there is a significantly higher risk of ACS above a cystatin C level of 727.85 ng/mL (OR: 5.5 CI [1.65-18.3], p = 0.004) and a significantly higher risk of STEMI above 915.22 ng/mL (OR: 5.9 CI [1.7-19.7], p = 0.003).

CONCLUSIONS

The available data suggest that a high cystatin C level is a risk factor for ACS and STEMI. This could play an important role in the early diagnosis and prevention of adverse cardiovascular events.

Heart rate variability and heart rate turbulence in patients with hematologic malignancies subjected to high-dose chemotherapy in the course of hematopoietic stem cell transplantation

BACKGROUND

In hematological malignancies, remissions and cures may be achieved by hematopoietic stem cell transplantation (HSCT) following high-dose chemotherapy (HDC). Cardiotoxicity of such therapy has not yet been fully elucidated. Noninvasive approaches allowing to evaluate an autonomic control of the heart function include analyses of both heart rate variability (HRV) and heart rate turbulence (HRT).

METHODS

In 38 patients with hematological malignancies, 24-hour electrocardiography Holter monitoring , with HRV and HRT analysis before HSCT (A test) and after HSCT (B test), was performed.

RESULTS

The 24-hour analysis of HRV demonstrated that SDNN, SDNNi, rMSSD, and pNN50 parameters were significantly lower after HSCT as compared to the results obtained before the transplantation (P < 0.05). For period of diurnal activity and for night hours, SDANN, SDNNi, rMSSD, and pNN50 were significantly lower in B test, as compared to the results of A test (P < 0.05). The analysis of HRT demonstrated that turbulence onset parameter was significantly higher, and turbulence slope parameter was significantly lower in B test, as compared to A test (P < 0.05). The multifactorial stepwise backward regression analysis indicated that administration of cyclophosphamide and carmustine and higher concentrations of blood cholesterol represented risk factors for decreased HRV. Cyclophosphamide and higher triglyceride levels represented independent risk factors for decreased HRT.

CONCLUSIONS

In patients with hematopoietic malignancies treated with HSCT, decreased HRV and HRT were observed after chemotherapy and stem cells administration.

Arterial-atrial coupling in untreated hypertension

Recently, there has been growing interest in an interplay of vascular mechanics and heart function (arterial-ventricular-atrial coupling). The contribution of arterial stiffness (AS) to left atrial (LA) enlargement is unclear. The aim of this study was to verify whether the association between carotid AS and LA volume in untreated arterial hypertension is independent of such confounders as age, sex, body mass index (BMI), blood pressure, left ventricular hypertrophy (LVH), left ventricular (LV) diastolic and systolic function. The study included 133 patients, among them 107 individuals with hypertension (51 men and 56 women, mean age 56.8 ± 10.3 years) and 26 matched controls. Each patient was subjected to echocardiography, ultrasonographic measurement of mean carotid intima-media thickness (IMT) and echo-tracking assessment of AS and wave reflection. LA volume was calculated by ellipsoid method. The indexed LA volume showed significant linear correlations with age (r = 0.32; p < 0.05), BMI (r = 0.21; p < 0.05), pulse pressure (r = 0.26; p < 0.05), B-type natriuretic peptide (r = 0.64; p < 0.05), LV end-diastolic volume (r = 0.42; p < 0.05), LV mass index (LVMI; r = 0.58; p < 0.05), septum thickness (r = 0.40; p < 0.05), posterior wall thickness (r = 0.34; p < 0.05), early filling wave of mitral inflow (E; r = 0.30; p < 0.05), early diastolic myocardial velocity of mitral annulus (e'; r = - 0.22; p < 0.05), E/e' ratio (r = 0.45; p < 0.05), IMT (r = 0.26; p < 0.05) and augmentation index (AI; r = 0.27; p < 0.05). Progressive multivariate analysis identified LVMI, age, AI and BMI as independent determinants of indexed LA volume in patients with arterial hypertension. The study showed the significant relationship between wave reflection expressed by AI and LA structural remodeling, which supports the hypothesis of arterial-atrial coupling in hypertension.

Electrocardiographic changes in workers occupationally exposed to lead

BACKGROUND

The significance of heavy metals in pathogenesis of the circulatory system diseases remains unresolved. The aim of the study was to evaluate electrocardiographic changes in workers occupationally exposed to lead without clinical presentation of cardiac involvement.

METHODS

A group of 60 smelters and refiners and 45 healthy men, as a control group, were enrolled. Twelve-lead electrocardiogram (ECG) and 24-hour Holter monitoring were performed. Further analysis included heart rate variability (HRV) in time and frequency domains and heart rate turbulence (HRT).

RESULTS

Analysis of 12-lead ECG recordings revealed various pathologies in 27 out of 60 men occupationally exposed to lead. Twenty-four-hour ECG Holter monitoring showed the higher mean heart rate in copper smelters than in healthy subjects (85.8 ± 14.1 bpm vs 72.6 ± 9.2 bpm; P < 0.05) and more premature supraventricular and ventricular contractions (298 ± 235 vs 27 ± 45; P < 0.05 and 152 ± 138 vs 18 ± 18; P < 0.05, respectively). The majority of time domain and frequency domain HRV parameters were significantly lower, and the LF:HF ratio was higher when compared with the control group. Turbulence onset was abnormal in six copper smelters and turbulence slope in five men exposed to lead.

CONCLUSIONS

Electrocardiographic evaluation showed that various heart rhythm disorders were more frequent in metallurgists, as compared to the control group, and the decreased HRV and abnormal parameters of HRT were observed. Noninvasive electrocardiographic evaluation could be a valuable method of the early prediction of cardiovascular disorders in men occupationally exposed to lead.

Environmental Factors as Modulators of the Relationship between Obstructive Sleep Apnea and Lesions in the Circulatory System

Obstructive sleep apnea (OSA) is a growing social problem, particularly in well-developed countries. It has been demonstrated that obstructive sleep apnea is a significant risk factor for cardiovascular diseases, including arterial hypertension, ischemic heart disease, heart failure, rhythm/conduction disturbances, as well as cerebral stroke. The pathophysiology of these diseases is complex and multifactorial. We present the current state of research on behavioral and environmental factors that influence the relationship between OSA and cardiovascular changes. We discuss the relationship between obesity, alcohol, sedatives, environmental tobacco smoke, allergic diseases and environmental pollution on the one hand and OSA on the other. In this context, the environment should be considered as an important modulator of the relationship between OSA and cardiovascular diseases.