Cardiovascular disease (CVD) is the leading cause of death worldwide. The most dangerous life‐threatening symptoms of CVD are myocardial infarction and stroke. The causes of CVD are not entirely clear, and new therapeutic targets are still being sought. One of the factors involved in CVD development among vascular damage and oxidative stress is chronic inflammation. It is known that hyaluronic acid plays an important role in inflammation and is regulated by numerous stimuli, including proinflammatory cytokines. The main receptors for hyaluronic acid are CD44 and RHAMM. These receptors are membrane proteins that differ in structure, but it seems that they can perform similar or synergistic functions in many diseases. Both RHAMM and CD44 are involved in cell migration and wound healing. However, their close association with CVD is not fully understood. In this review, we describe the role of both receptors in CVD.

Glioblastomas (GBM) are the most common, primary brain tumors in adults. Despite advances in neurosurgery and radio- and chemotherapy, the median survival of GBM patients is 15 months. Recent large-scale genomic, transcriptomic and epigenetic analyses have shown the cellular and molecular heterogeneity of GBMs, which hampers the outcomes of standard therapies. We have established 13 GBM-derived cell cultures from fresh tumor specimens and characterized them molecularly using RNA-seq, immunoblotting and immunocytochemistry. Evaluation of proneural (OLIG2, IDH1^R132H, TP53 and PDGFRα), classical (EGFR) and mesenchymal markers (CHI3L1/YKL40, CD44 and phospho-STAT3), and the expression of pluripotency (SOX2, OLIG2, NESTIN) and differentiation (GFAP, MAP2, β-Tubulin III) markers revealed the striking intertumor heterogeneity of primary GBM cell cultures. Upregulated expression of VIMENTIN, N-CADHERIN and CD44 at the mRNA/protein levels suggested increased epithelial-to-mesenchymal transition (EMT) in most studied cell cultures. The effects of temozolomide (TMZ) or doxorubicin (DOX) were tested in three GBM-derived cell cultures with different methylation status of the MGMT promoter. Amongst TMZ- or DOX-treated cultures, the strongest accumulation of the apoptotic markers caspase 7 and PARP were found in WG4 cells with methylated MGMT, suggesting that its methylation status predicts vulnerability to both drugs. As many GBM-derived cells showed high EGFR levels, we tested the effects of AG1478, an EGFR inhibitor, on downstream signaling pathways. AG1478 caused decreased levels of phospho-STAT3, and thus inhibition of active STAT3 augmented antitumor effects of DOX and TMZ in cells with methylated and intermediate status of MGMT. Altogether, our findings show that GBM-derived cell cultures mimic the considerable tumor heterogeneity, and that identifying patient-specific signaling vulnerabilities can assist in overcoming therapy resistance, by providing personalized combinatorial treatment recommendations.

Opioid peptides and their G protein-coupled receptors are important regulators within the cardiovascular system, implicated in the modulation of both heart and vascular functions. It is known that naloxone—an opioid antagonist—may exert a hypertensive effect. Recent experimental and clinical evidence supports the important role of inflammatory mechanisms in hypertension. Since opioids may play a role in the regulation of both blood pressure and immune response, we studied these two processes in our model. We aimed to evaluate the effect of selective and non-selective opioid receptor antagonists on blood pressure and T-cell activation in a mouse model of high swim stress-induced analgesia. Blood pressure was measured before and during the infusion of opioid receptor antagonists using a non-invasive tail–cuff measurement system. To assess the activation of T-cells, flow cytometry was used. We discovered that the non-selective antagonism of the opioid system by naloxone caused a significant elevation of blood pressure. The selective antagonism of μ and κ but not δ opioid receptors significantly increased systolic blood pressure. Subsequently, a brief characterization of T-cell subsets was performed. We found that the blockade of μ and δ receptors is associated with the increased expression of CD69 on CD4 T-cells. Moreover, we observed an increase in the central memory CD4 and central memory CD8 T-cell populations after the δ opioid receptor blockade. The antagonism of the μ opioid receptor increased the CD8 effector and central memory T-cell populations.

The opioid system is well-known for its role in modulating nociception and addiction development. However, there are premises that the endogenous opioid system may also affect blood pressure. The main goal of the present study was to determine the impact of different endogenous opioid system activity and its pharmacological blockade on blood pressure. Moreover, we examined the vascular function in hyper- and hypoactive states of the opioid system and its pharmacological modification. In our study, we used two mouse lines which are divergently bred for high (HA) and low (LA) swim stress-induced analgesia. The obtained results indicated that individuals with low endogenous opioid system activity have higher basal blood pressure compared to those with a hyperactive opioid system. Additionally, naloxone administration only resulted in the elevation of blood pressure in HA mice. We also showed that the hypoactive opioid system contributes to impaired vascular relaxation independent of endothelium, which corresponded with decreased guanylyl cyclase levels in the aorta. Together, these data suggest that higher basal blood pressure in LA mice is a result of disturbed mechanisms in vascular relaxation in smooth muscle cells. We believe that a novel mechanism which involves endogenous opioid system activity in the regulation of blood pressure will be a promising target for further studies in hypertension development.

Opioids are a challenging class of drugs due to their dual role. They alleviate pain, but also pose a risk of dependency, or trigger constipation, particularly in cancer patients, who require the more potent painkillers in more advanced stages of the disease, closely linked to pain resulting from general inflammation, bone metastases, and primary or secondary tumour outgrowth-related nerve damage. Clinicians’ vigilance considering treatment with opioids is necessary, bearing in mind extensive data accumulated over decades that have reported the contribution of opioids to immunosuppression, tumour progression, or impaired tissue regeneration, either following opioid use during surgical tumour resection and post-surgical pain treatment, or as a result of other diseases like diabetes, where chronic wounds healing constitutes a challenge. During last few years, an increasing trend for seeking relationships between opioids and epithelial–mesenchymal transition (EMT) in cancer research can be observed. Transiently lasting EMT is desirable during wound healing, but in cancer, or vital organ fibrogenesis, EMT appears to be an obstacle to overcome, forcing to adjust treatment strategies that would reduce the risk for worsening of the disease outcome and patient prognosis. The same opioid may demonstrate promoting or inhibitory effect on EMT, dependently on various conditions in particular clinical cases. We have summarized current findings on this issue to uncover some rules that govern opioid-mediated EMT induction or repression; however, many aspects still remain to be elucidated.

Background: The endogenous opioid system plays a pivotal role in numerous physiological processes and is implicated in a range of diseases, including atherosclerosis, a condition contributing to nearly 50% of deaths in Western societies. Objectives: This study investigates the effects of opioid receptor blockade, using naloxone, on the plasma lipid profile and atherosclerosis progression. Methods: ApoE^−/− mice with advanced atherosclerosis were treated with naloxone for seven days, and the effects on atherosclerotic plaque development and liver steatosis were evaluated. Results: A proteomic analysis of liver samples post-treatment identified 38 proteins with altered abundance. The results revealed that naloxone treatment led to an increase in HDL cholesterol, a lipid fraction associated with protective cardiovascular effects. Furthermore, naloxone did not influence the progression of atherosclerotic plaques or the development of liver steatosis. Conclusions: In conclusion, while short-term naloxone treatment in mice with advanced atherosclerosis does not alter overall atherosclerotic plaque progression or liver steatosis, the observed elevation in HDL cholesterol and the extensive changes in liver protein abundance underscore the complex and multifaceted role of the opioid system in lipid metabolism and cardiovascular health. These findings provide a foundation for further exploration of opioid receptor antagonists as modulators of lipid profiles and potential contributors to cardiovascular therapy.