Osteoprotegerin Is Essential for the Development of Endothelial Dysfunction Induced by Angiotensin II in Mice.

Opinions on the effects of osteoprotegerin (OPG) have evolved over the years from a protein protecting the vasculature from calcification to a cardiovascular risk factor contributing to inflammation within the vascular wall. Nowadays, the link between OPG and angiotensin II (Ang II) appears to be particularly important. In this study, the endothelial function was investigated in OPG-knockout mice (B6.129.S4-OPG, OPG-) and wild-type (C57BL/6J, OPG+) mice under basic conditions and after Ang II exposure by assessing the endothelium-dependent diastolic response of aortic rings to acetylcholine in vitro. A further aim of the study was to compare the effect of Ang II on the expression of cytokines in the aortic wall of both groups of mice. Our study shows that rings from OPG- mice had their normal endothelial function preserved after incubation with Ang II, whereas those from OPG+ mice showed significant endothelial dysfunction. We conclude that the absence of OPG, although associated with a pro-inflammatory cytokine profile in the vascular wall, simultaneously protects against Ang II-induced increases in pro-inflammatory cytokines in the murine vascular wall. Our study also demonstrates that the absence of OPG can result in a decrease in the concentration of pro-inflammatory cytokines in the vascular wall after Ang II exposure. The presence of OPG is therefore crucial for the development of Ang II-induced inflammation in the vascular wall and for the development of Ang II-induced endothelial dysfunction.

The role of PCSK9 in heart failure and other cardiovascular diseases-mechanisms of action beyond its effect on LDL cholesterol.

Proprotein convertase subtilisin/kexin type-9 (PCSK9) is a protein that regulates low-density lipoprotein (LDL) cholesterol metabolism by binding to the hepatic LDL receptor (LDLR), ultimately leading to its lysosomal degradation and an increase in LDL cholesterol (LDLc) levels. Treatment strategies have been developed based on blocking PCSK9 with specific antibodies (alirocumab, evolocumab) and on blocking its production with small regulatory RNA (siRNA) (inclisiran). Clinical trials evaluating these drugs have confirmed their high efficacy in reducing serum LDLc levels and improving the prognosis in patients with atherosclerotic cardiovascular diseases. Most studies have focused on the action of PCSK9 on LDLRs and the subsequent increase in LDLc concentrations. Increasing evidence suggests that the adverse cardiovascular effects of PCSK9, particularly its atherosclerotic effects on the vascular wall, may also result from mechanisms independent of its effects on lipid metabolism. PCSK9 induces the expression of pro-inflammatory cytokines contributing to inflammation within the vascular wall and promotes apoptosis, pyroptosis, and ferroptosis of cardiomyocytes and is thus involved in the development and progression of heart failure. The elimination of PCSK9 may, therefore, not only be a treatment for hypercholesterolaemia but also for atherosclerosis and other cardiovascular diseases. The mechanisms of action of PCSK9 in the cardiovascular system are not yet fully understood. This article reviews the current understanding of the mechanisms of PCSK9 action in the cardiovascular system and its contribution to cardiovascular diseases. Knowledge of these mechanisms may contribute to the wider use of PCSK9 inhibitors in the treatment of cardiovascular diseases.

Ferroptosis, Acyl Starvation, and Breast Cancer.

To maintain their growth rate, cancer cells must secure a supply of fatty acids, which are necessary for building cell membranes and maintaining energy processes. This is one of the reasons why tissues with intensive fatty acid metabolism, such as the mammary gland, are more likely to develop tumors. One natural or induced defense process against cancer is ferroptosis, which interferes with normal fatty acid metabolism. This leads to the oxidation of polyunsaturated fatty acids, which causes a rearrangement of the metabolism and damages cell membranes. As a consequence of this oxidation, there is a shortage of normal polyunsaturated fatty acids, which disturbs the complicated metabolism of fatty acids. This imbalance in metabolism, resulting from the deficiency of properly structured fatty acids, is called, by these authors, "acyl starvation." When cancer cells are exposed to alternating hypoxia and reoxygenation, they often develop resistance to neoadjuvant therapies. Blocking the stearoyl-CoA desaturase - fatty acid-binding protein 4 - fatty acid translocase axis appears to be a promising pathway in the treatment of breast cancer. On the one hand, the inhibition of desaturase leads to the formation of toxic phospholipid hydroperoxides in ferroptosis, whereas on the other hand, the inhibition of fatty acid-binding protein 4 and translocase leads to a reduced uptake of fatty acids and disruption of the cellular transport of fatty acids, resulting in intracellular acyl starvation. The disruption in the metabolism of fatty acids in cancer cells may augment the effectiveness of neoadjuvant therapy. SIGNIFICANCE STATEMENT: Regulation of the metabolism of fatty acids in cancer cells seems to be a promising therapeutic direction. Studies show that the induction of ferroptosis in cancer cells, combined with use of neoadjuvant therapies, effectively inhibits the proliferation of these cells. We link the process of ferroptosis with apoptosis and SCD1-FABP4-CD36 axis and propose the term "acyl starvation" for the processes leading to FA deficiency, dysregulation of FA metabolism in cancer cells, and, most importantly, the appearance of incorrect proportions FAs.

Placental expression of Fatty Acid Desaturases 1, 2 and 3 in selected pregnancy pathologies.

Intrauterine development is a key period in human life. The foetal progress largely depends on the function of the placenta, whose responsibility is transportation and biosynthesis of fatty acids. Desaturation enzymes play a key role in placental fatty acid metabolism. Expression of genes coding for desaturases may be associated with pregnancy abnormalities. The objective of this study was to determine the transcriptional activity of the placental genes Fatty Acid Desaturases 1, 2 and 3 (FADS 1, 2 and 3) in women who gave birth to the infants appropriate for gestational age, large for gestational age, small for gestational age, with intrauterine growth restriction and born preterm. 34 pregnant women aged 21-37 years old participated in the study. The placental samples were taken from a site located 2-3 cm away from the umbilical cord attachment. The collected tissue sections were stored in RNAlater according to the manufacturer's protocol, until required for molecular analysis. The expression profiles of FADS1, FADS2 and FADS3 were determined with RT-qPCR. There was no difference in FADS1 and FADS2 expression between the groups. However, the differences in the expression of the FADS3 were found. Analysis of the FADS1, FADS2 and FADS3 transcription showed significant differences between most of the examined groups. Our findings suggest that the transcriptional activity of FADS genes changes with the severity of intrauterine disorders and is associated with foetal lipid disorders linked to a greater accumulation of fat in the foetal tissues.

SGLT-2 Inhibitors in Cancer Treatment-Mechanisms of Action and Emerging New Perspectives.

A new group of antidiabetic drugs, sodium-glucose cotransporter 2 inhibitors (SGLT-2 inhibitors), have recently been shown to have anticancer effects and their expression has been confirmed in many cancer cell lines. Given the metabolic reprogramming of these cells in a glucose-based model, the ability of SGLT-2 inhibitors to block the glucose uptake by cancer cells appears to be an attractive therapeutic approach. In addition to tumour cells, SGLT-2s are only found in the proximal tubules in the kidneys. Furthermore, as numerous clinical trials have shown, the use of SGLT-2 inhibitors is well-tolerated and safe in patients with diabetes and/or heart failure. In vitro cell culture studies and preclinical in vivo studies have confirmed that SGLT-2 inhibitors exhibit antiproliferative effects on certain types of cancer. However, the mechanisms of this action remain unclear. Even in those tumour cell types in which SGLT-2 is present, there is sometimes an SGLT-2-independent mechanism of anticancer action of this group of drugs. This article presents the current state of knowledge of the potential mechanisms of the anticancer action of SGLT-2 inhibitors and their possible future application in clinical oncology.

Analysis of Emergency Medical Response Team Performance during the International Winter Championships in Emergency Medicine.

Background and Objectives: Conducting advanced life support (ALS) according to the guidelines of the European Resuscitation Council (ERC) requires medical personnel to implement the appropriate emergency actions. In particular, these actions include chest compressions, airway management, artificial ventilation, defibrillation and the administering of medicines. An appropriate training system enables members of medical response teams (MRT) to acquire the essential knowledge and skills necessary to correctly conduct cardiopulmonary resuscitation (CPR). One way to improve the quality of interventions by MRT personnel is participation in emergency medicine championships. Materials and Methods: The research analysed assessment cards for tasks carried out during the International Winter Championships in Emergency Medicine in the years 2013-2020. The assessed tasks were prepared and led by European Resuscitation Council instructors of advanced life support. During ten-minute scenarios of simulated sudden cardiac arrest (SCA) in adults, the judges assessed the compliance of procedures with current ERC guidelines. This research analysed the performance of 309 teams from Poland made up of paramedics from medical response units from all over the country. Results: In most cases, the study showed significant differences in the percentage of correctly performed procedures between years. Most often, the highest percentage of correctly performed procedures was recorded in 2019 and 2020. The lowest percentage of correctly performed procedures was most often recorded in 2013. In subsequent years, the percentage of use of tracheal intubation decreased (from 54.76% to 31.25%) in favour of an increase in the use of supraglottic airway device SAD (from 35.71% to 59.38%). Conclusions: The research has shown that in subsequent years of the Championships, the quality of the majority of assessed procedures carried out by members of MRT gradually improved. The research authors also observed that in subsequent years, the percentage of intubations decreased in favour of SAD.

The Influence of Graphene Content on the Antibacterial Properties of Polycaprolactone.

This work contains an analysis of the impact of modifying a bioresorbable polymer-polycaprolactone (PCL)-with various additives on its antibacterial properties. To this end, samples of PCL filament containing various content levels of graphene (GNP), 0.5%, 5%, 10%, were obtained using injection molding. Polymer samples without additives were used for comparison. The next step was to assess the antimicrobial impact of the preparations under study against the following microorganisms: Staphylococcus aureus ATCC 25293, Escherichia coli ATCC 25922, Candida albicans ATCC 10231. Effective bactericidal activity of PCL with small amount of GNP, especially against C. albicans and S. aureus was confirmed. A decrease in this property or even multiplication of microorganisms was observed in direct proportion to the graphene content in the samples.

Open craniocerebral trauma in a patient at work: A case report.

BACKGROUND: Craniocerebral injuries belong to the category of bodily injuries which are characterised by high mortality and a high percentage of permanent effects in the form of disability. The likelihood of this injury exists in the workplace too. Performing works at a height or using high-pressure or mechanical machinery exposes employees to a higher risk of a craniocerebral injury. CASE REPORT: This case study deals with the topic of open craniocerebral trauma suffered by a 20-year-old man who was wearing no head protection at his place of work. It details the management of this trauma at the site of the accident, during transfer to the hospital and during hospitalisation. CONCLUSION: Fast transport, effective diagnostics and implementation of surgical treatment contributed to a good final result.

Osteoprotegerin and RANKL-RANK-OPG-TRAIL signalling axis in heart failure and other cardiovascular diseases.

Osteoprotegerin (OPG) is a glycoprotein involved in the regulation of bone remodelling. OPG regulates osteoclast activity by blocking the interaction between the receptor activator of nuclear factor kappa B (RANK) and its ligand (RANKL). More and more studies confirm the relationship between OPG and cardiovascular diseases. Numerous studies have confirmed that a high plasma concentration of OPG and a low concentration of tumour necrosis factor-related apoptosis inducing ligand (TRAIL) together with a high OPG/TRAIL ratio are predictors of poor prognosis in patients with myocardial infarction. A high plasma OPG concentration and a high ratio of OPG/TRAIL in the acute myocardial infarction are a prognostic indicator of adverse left ventricular remodelling and of the development of heart failure. Ever more data indicates the participation of OPG in the regulation of the function of vascular endothelial cells and the initiation of the atherosclerotic process in the arteries. Additionally, it has been shown that TRAIL has a protective effect on blood vessels and exerts an anti-atherosclerotic effect. The mechanisms of action of both OPG and TRAIL within the cells of the vascular wall are complex and remain largely unclear. However, these mechanisms of action as well as their interaction in the local vascular environment are of great interest to researchers. This article presents the current state of knowledge on the mechanisms of action of OPG and TRAIL in the circulatory system and their role in cardiovascular diseases. Understanding these mechanisms may allow their use as a therapeutic target in cardiovascular diseases in the future.

Analysis of the antibacterial properties of polycaprolactone modified with graphene, bioglass and zinc-doped bioglass.

PURPOSE: Innovative biomedical filaments for 3D printing in the form of short and biodegradable composite sticks modified with various additives were used to prepare biomaterials for further nasal implants. As the respiratory tract is considered to be potentially exposed to contamination during the implantation procedure there is a need to modify the implant with an antibacterial additives. The purpose of this work was to analyze the effect of biodegradable polymer - polycaprolactone (PCL) modification with various additives on its antibacterial properties. METHODS: PCL filament modified with graphene (0.5, 5, 10% wt.), bioglass (0.4% wt.) and zinc-doped bioglass (0.4% wt.) were used to print spatial biomaterials using FDM 3D printer. Pure polymer biomaterials without additives were used as reference samples. The key task was to assess the antimicrobial impact of the prepared biomaterials against the following microorganisms: Staphylococcus aureus ATCC 25293, Escherichia coli ATCC 25922, Candida albicans ATCC 10231. RESULTS: The research results point to a significant antibacterial efficacy of the tested materials against S. aureus and C. albicans, which, however, seems to decrease with increasing graphene content in the filaments. A complete lack of antibacterial efficacy against E. coli was determined. CONCLUSIONS: The tested biomaterials have important antibacterial properties, especially against C. albicans. The obtained results showed that biomaterials made of modified filaments can be successfully used in implantology, where a need to create temporary tissue scaffolds occurs.

Patient knowledge at the Respiratory Ward of the Railway Hospital in Wilkowice-Bystra about preventive treatments to combat house dust mites and alleviate allergy symptoms.

House dust mite allergy is a serious problem that affects about six million people in Poland and if left untreated could be the reason for the development of bronchial asthma. The main purpose of this study was to analyse how aware the patients in the respiratory ward were about the prevention of allergic diseases caused by house dust mites and the prophylactic measures that can be taken. The study took place between September 2018 and November 2018 and involved 109 patients, hospitalised in the Respiratory Ward of the Railway Hospital in Wilkowic-Bystra, who had been diagnosed with asthma and house dust mite allergy. People between 51 and 60 years of age comprised the largest group of respondents. A diagnostic survey method was utilised for the study, whereby the survey data was collected by way of a questionnaire completed by the participants. Most people (45.0%) experience an increase in allergy symptoms when cleaning the house and when sleeping at night (35.0%). Over half of the respondents (59.0%) believe, that the main places in which dust mites are found in the home are rugs, blankets and bedding. According to respondents (40.0%), prophylactic treatments against dust mite allergy at home are effective in alleviating the symptoms. Most respondents use preventive measures to combat house dust mites and relieve allergy symptoms. The main source of information about the prevention of allergic diseases is a doctor.

Local electromechanical alterations determine the left ventricle rotational dynamics in CRT-eligible heart failure patients.

Left ventricle, LV wringing wall motion relies on physiological muscle fiber orientation, fibrotic status, and electromechanics (EM). The loss of proper EM activation can lead to rigid-body-type (RBT) LV rotation, which is associated with advanced heart failure (HF) and challenges in resynchronization. To describe the EM coupling and scar tissue burden with respect to rotational patterns observed on the LV in patients with ischemic heart failure with reduced ejection fraction (HFrEF) left bundle branch block (LBBB). Thirty patients with HFrEF/LBBB underwent EM analysis of the left ventricle using an invasive electro-mechanical catheter mapping system (NOGA XP, Biosense Webster). The following parameters were evaluated: rotation angle; rotation velocity; unipolar/bipolar voltage; local activation time, LAT; local electro-mechanical delay, LEMD; total electro-mechanical delay, TEMD. Patients underwent late-gadolinium enhancement cMRI when possible. The different LV rotation pattern served as sole parameter for patients' grouping into two categories: wringing rotation (Group A, n = 6) and RBT rotation (Group B, n = 24). All parameters were aggregated into a nine segment, three sector and whole LV models, and compared at multiple scales. Segmental statistical analysis in Group B revealed significant inhomogeneities, across the LV, regarding voltage level, scar burdening, and LEMD changes: correlation analysis showed correspondently a loss of synchronization between electrical (LAT) and mechanical activation (TEMD). On contrary, Group A (relatively low number of patients) did not present significant differences in LEMD across LV segments, therefore electrical (LAT) and mechanical (TEMD) activation were well synchronized. Fibrosis burden was in general associated with areas of low voltage. The rotational behavior of LV in HF/LBBB patients is determined by the local alteration of EM coupling. These findings serve as a strong basic groundwork for a hypothesis that EM analysis may predict CRT response.Clinical trial registration: SUM No. KNW/0022/KB1/17/15.

Sodium glucose cotransporter 2 inhibitors: mechanisms of action in heart failure.

Diabetes is a key independent risk factor in the development of heart failure (HF) and a strong, adverse prognostic factor in HF patients. HF remains the primary cause of hospitalisation for diabetics and, as previous studies have shown, when HF occurs in these patients, intensive glycaemic control does not directly improve the prognosis. Recent clinical studies assessing a new class of antidiabetic drugs, sodium-glucose cotransporter 2 inhibitors (SGLT2is) showed some unexpected beneficial results. Patients treated with SGLT2is had a significant decrease in both cardiovascular (CV) and all-cause mortality and less hospitalisations due to HF compared to those given a placebo. These significant clinical benefits occurred quickly after the drugs were administered and were not solely due to improved glycaemic control. These groundbreaking clinical trials' results have already changed clinical practice in the management of patients with diabetes at high CV risk. These trials have triggered numerous experimental studies aimed at explaining the mechanisms of action of this unique group of drugs. This article presents the current state of knowledge about the mechanisms of action of SGLT2is developed for the treatment of diabetes and which, thanks to their cardioprotective effects, may, in the future, become a treatment for patients with HF.

Various aspects of inflammation in heart failure.

Despite significant advances in the prevention and treatment of heart failure (HF), the prognosis in patients who have been hospitalised on at least one occasion due to exacerbation of HF is still poor. Therefore, a better understanding of the underlying pathophysiological mechanisms of HF is crucial in order to achieve better results in the treatment of this clinical syndrome. One of the areas that, for years, has aroused the interest of researchers is the activation of the immune system and the elevated levels of biomarkers of inflammation in patients with both ischaemic and non-ischaemic HF. Additionally, it is intriguing that the level of circulating pro-inflammatory biomarkers correlates with the severity of the disease and prognosis in this group of patients. Unfortunately, clinical trials aimed at assessing interventions to modulate the inflammatory response in HF have been disappointing, and the modulation of the inflammatory response has had either no effect or even a negative effect on the HF prognosis. The article presents a summary of current knowledge on the role of immune system activation and inflammation in the pathogenesis of HF. Understanding the immunological mechanisms pathogenetically associated with left ventricular remodelling and progression of HF may open up new therapeutic possibilities for HF.

Comparison of standard and over-the-head method of chest compressions during cardiopulmonary resuscitation - a simulation study.

BACKGROUND: Maintaining highly effective cardiopulmonary resuscitation (CPR) can be particularly difficult when artificial ventilation using a bag-valve-mask device, combined with chest compression have to be carried out by one person. The aim of the study is to compare the quality of CPR conducted by one paramedic using chest compression from the patient's side with compression conducted from the 'over-the-head' position. METHODS: The subject of the study were two methods of CPR - 'standard' (STD) and 'over-the-head' (OTH). The STD method consisted of cycles of 30 chest compressions from the patient's side, and two attempts at artificial ventilation after moving round to behind the patient's head. In the OTH method, both compressions and ventilations were conducted from behind the patient's head. RESULTS: Both CPR methods were conducted by 38 paramedics working in medical response teams. Statistical analysis was conducted on the data collected, giving the following results: the average time of the interruptions between compression cycles (STD 9.184 s, OTH 7.316 s, p < 0.001); the depth of compression 50-60 mm (STD 50.65%, OTH 60.22%, p < 0.001); the rate of compression 100-120/min. (STD 46.39%, OTH 53.78%, p < 0.001); complete chest wall recoil (STD 84.54%, OTH 91.46%, p < 0.001); correct hand position (STD 99.32%, OTH method 99.66%, p < 0.001). A statistically significant difference was demonstrated in the results to the benefit of the OTH method in the above parameters. The remaining parameters showed no significant differences in comparison to reference values. CONCLUSIONS: The higher quality of CPR in the simulated research using the OTH method by a single person justifies the use of this method in a wider range of emergency interventions.

Serum Concentrations of Osteogenesis/Osteolysis-Related Factors and Micro-RNA Expression in ST-Elevation Myocardial Infarction.

BACKGROUND: Atherosclerosis and bone metabolism share similar molecular and cellular mechanisms. This study aims to evaluate (1) serum concentration of osteogenesis/osteolysis factors panel (Dickkopf-related protein 1 (DKK-1), TNF-α, N-terminal atrial natriuretic peptide (NT-proANP), thrombospondin-2 (TSP-2), osteoprotegerin (OPG), osteocalcin (OCN), osteopontin (OPN), fibroblast growth factor 23 (FGF-23), soluble receptor activator of nuclear factor-kappaB ligand (sRANKL), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), proprotein convertase subtilisin/kexin type 9 (PCSK9)), (2) serum expression levels of micro-RNA- (miR-) 24-1 and miR-6802, and (3) assess their correlation with myocardial injury and LV remodeling and function in the acute phase of STEMI and after 3 months. METHODS: Study enrolled 25 STEMI patients (mean age 55.4 ± 8.96 years). Blood samples were collected 4 days and 3 months after myocardial infarction. Serum concentrations of osteogenesis/osteolysis factors were measured using the Luminex assay. Analysis of miR-24-1, and miR-6802 expression was performed with qPCR. LV function and remodeling were assessed by MRI during index hospitalization and 3 months later. RESULTS: There were no significant differences in serum levels of osteogenesis/osteolysis factors and expression of miR-24-1 and miR-6802 between the acute phase and 3-month follow-up. The levels were similar in patients with at least ≥5% improvement of LVEF (n = 10) and those without improvement. There was a negative correlation between the OPG serum level and LVEF during the acute phase of myocardial infarction. CONCLUSIONS: In STEMI patients, serum concentrations of osteogenesis/osteolysis factors, as well as miR-24-1 and miR-6802 expression, do not change significantly within the 3-month follow-up and are not correlated with LV remodeling and function.

Self-regulation of the inflammatory response by peroxisome proliferator-activated receptors.

The peroxisome proliferator-activated receptor (PPAR) family includes three transcription factors: PPARα, PPARß/δ, and PPARγ. PPAR are nuclear receptors activated by oxidised and nitrated fatty acid derivatives as well as by cyclopentenone prostaglandins (PGA2 and 15d-PGJ2) during the inflammatory response. This results in the modulation of the pro-inflammatory response, preventing it from being excessively activated. Other activators of these receptors are nonsteroidal anti-inflammatory drug (NSAID) and fatty acids, especially polyunsaturated fatty acid (PUFA) (arachidonic acid, ALA, EPA, and DHA). The main function of PPAR during the inflammatory reaction is to promote the inactivation of NF-κB. Possible mechanisms of inactivation include direct binding and thus inactivation of p65 NF-κB or ubiquitination leading to proteolytic degradation of p65 NF-κB. PPAR also exert indirect effects on NF-κB. They promote the expression of antioxidant enzymes, such as catalase, superoxide dismutase, or heme oxygenase-1, resulting in a reduction in the concentration of reactive oxygen species (ROS), i.e., secondary transmitters in inflammatory reactions. PPAR also cause an increase in the expression of IκBα, SIRT1, and PTEN, which interferes with the activation and function of NF-κB in inflammatory reactions.

The relevance of microRNA in post-infarction left ventricular remodelling and heart failure.

Myocardial infarction and post-infarction left ventricular remodelling involve a high risk of morbidity and mortality. For this reason, ongoing research is being conducted in order to learn the mechanisms of unfavourable left ventricular remodelling following a myocardial infarction. New biomarkers are also being sought that would allow for early identification of patients with a high risk of post-infarction remodelling and dysfunction of the left ventricle. In recent years, there has been ever more experimental data that confirms the significance of microRNA in cardiovascular diseases. It has been confirmed that microRNAs are stable in systemic circulation, and can be directly measured in patients' blood. It has been found that significant changes occur in the concentrations of various types of microRNA in myocardial infarction and heart failure patients. Various types of microRNA are also currently being intensively researched in terms of their usefulness as markers of cardiomyocyte necrosis, and predictors of the post-infarction heart failure development. This paper is a summary of the current knowledge on the significance of microRNA in post-infarction left ventricular remodelling and heart failure.

[Osteoprotegerin ­ is it only a cardiovascular risk marker?].

Osteoprotegerin is a glycoprotein contributing to the regulation of bone rebuilding. It has been documented that osteoprotegerin regulates the activity of osteoclasts by blocking the interaction between the receptor, activator nuclear factor kappa B (RANK) and its ligand (RANKL). Osteoprotegerin, by blocking the connection between RANKL and its receptor (RANK), inhibits the maturation of osteoclasts and osteoclastogenesis and because of this, it inhibits the osteolytic processes. The participation of osteoprotegerin in regulating the function of immune system cells has also been confirmed. More and more studies confirm, that osteoprotegerin is associated with cardiovascular diseases. In many studies it has been confirmed that high plasma concentration of osteoprotegerin and low concentration of TNF ­ related apoptosis inducing ligand (TRAIL) and high OPG/TRAIL ratio are predictors of a poor prognosis in patients with myocardial infarction. High plasma concentration and high OPG/TRAIL ratio in the acute phase of myocardial infarction are mainly prognostic indicators of adverse left ventricular remodelling and the development of postinfarction heart failure. In a group of patients with high plasma concentration of osteoprotegerin in the acute phase of myocardial infarction, it has also been established that there are a lower number of mesenchymal stem cells (MSC) recruited from bone marrow and circulating in peripheral blood. Pathogenic mechanisms which involve osteoprotegerin and which are responsible for both postinfarction left ventricular remodelling and prognosis after myocardial infarction are being researched amid great excitement. This is mainly because it offers the possibility of identifying the defence mechanisms which protect the left ventricular against adverse remodelling after myocardial infarction. This would offer us the possibility of using osteoprotegerin not only as a prognostic marker in cardiovascular diseases but also as a potential therapeutic target in cardiovascular diseases. This review presents the current knowledge about this.