S100B: a multifunctional role in cardiovascular pathophysiology

Glial cell activity in cardiovascular diseases and risk of acute myocardial infarction

Growing evidence indicates that the pathophysiological link between the brain and heart underlies cardiovascular diseases, specifically acute myocardial infarction (AMI). Astrocytes are the most abundant glial cells in the central nervous system and provide support/protection for neurons. Astrocytes and peripheral glial cells are emerging as key modulators of the brain-heart axis in AMI, by affecting sympathetic nervous system activity (centrally and peripherally). This review, therefore, aimed to gain an improved understanding of glial cell activity and AMI risk. This includes discussions on the potential role of contributing factors in AMI risk, i.e., autonomic nervous system dysfunction, glial-neurotrophic and ischemic risk markers [glial cell line-derived neurotrophic factor (GDNF), astrocytic S100 calcium-binding protein B (S100B), silent myocardial ischemia, and cardiac troponin T (cTnT)]. Consideration of glial cell activity and related contributing factors in certain brain-heart disorders, namely, blood-brain barrier dysfunction, myocardial ischemia, and chronic psychological stress, may improve our understanding regarding the pathological role that glial dysfunction can play in the development/onset of AMI. Here, findings demonstrated perturbations in glial cell activity and contributing factors (especially sympathetic activity). Moreover, emerging AMI risk included sympathovagal imbalance, low GDNF levels reflecting prothrombic risk, hypertension, and increased ischemia due to perfusion deficits (indicated by S100B and cTnT levels). Such perturbations impacted blood-barrier function and perfusion that were exacerbated during psychological stress. Thus, greater insights and consideration regarding such biomarkers may help drive future studies investigating brain-heart axis pathologies to gain a deeper understanding of astrocytic glial cell contributions and unlock potential novel therapies for AMI.

Salivary S100 calcium-binding protein beta (S100B) and neurofilament light (NfL) after acute exposure to repeated head impacts in collegiate water polo players

Blood-based biomarkers of brain injury may be useful for monitoring brain health in athletes at risk for concussions. Two putative biomarkers of sport-related concussion, neurofilament light (NfL), an axonal structural protein, and S100 calcium-binding protein beta (S100B), an astrocyte-derived protein, were measured in saliva, a biofluid which can be sampled in an athletic setting without the risks and burdens associated with blood sampled by venipuncture. Samples were collected from men’s and women’s collegiate water polo players (n = 65) before and after a competitive tournament. Head impacts were measured using sensors previously evaluated for use in water polo, and video recordings were independently reviewed for the purpose of validating impacts recorded by the sensors. Athletes sustained a total of 107 head impacts, all of which were asymptomatic (i.e., no athlete was diagnosed with a concussion or more serious). Post-tournament salivary NfL was directly associated with head impact frequency (RR = 1.151, p = 0.025) and cumulative head impact magnitude (RR = 1.008, p = 0.014), while controlling for baseline salivary NfL. Change in S100B was not associated with head impact exposure (RR < 1.001, p > 0.483). These patterns suggest that repeated head impacts may cause axonal injury, even in asymptomatic athletes.

Role of Biomarkers in the Integrated Management of Melanoma

Melanoma, which is an aggressive skin cancer, is currently the fifth and seventh most common cancer in men and women, respectively. The American Cancer Society reported that approximately 106,110 new cases of melanoma were diagnosed in the United States in 2021, with 7,180 people dying from the disease. This information could facilitate the early detection of possible metastatic lesions and the development of novel therapeutic techniques for melanoma. Additionally, early detection of malignant melanoma remains an objective of melanoma research. Recently, melanoma treatment has substantially improved, given the availability of targeted treatments and immunotherapy. These developments have highlighted the significance of identifying biomarkers for prognosis and predicting therapy response. Biomarkers included tissue protein expression, circulating DNA detection, and genetic alterations in cancer cells. Improved diagnostic and prognostic biomarkers are becoming increasingly relevant in melanoma treatment, with the development of newer and more targeted treatments. Here, the author discusses the aspects of biomarkers in the real-time management of patients with melanoma.

Expression and related mechanisms of miR-330-3p and S100B in an animal model of cartilage injury

Objective

To investigate the roles of and relationship between microRNA (miR)-330-3p and S100 calcium-binding protein B (S100B) in an animal model of cartilage injury.

Methods

This study included 30 New Zealand male rabbits randomly divided into three groups: an intervention group, a model group and a sham surgery control group. Modelling was performed in the intervention and model groups, but in the sham surgery group, only the skin was cut. After modelling, the intervention and model groups were injected with the miR-330-3p overexpression vector GV268-miR-330-3p or the control GV268-N-ODN vector, respectively, twice a week for 7 weeks.

Results

Levels of interleukin-1β and tumour necrosis factor-α in the synovial fluid were significantly higher in the model group than in the intervention and control groups. The level of miR-330-3p in the cartilage tissue was significantly higher in the control group than in the model group but it was significantly lower compared with the intervention group. Levels of S100B, fibroblast growth factor receptor 1 and fibroblast growth factor-2 in the cartilage tissue of rabbits in the model group were significantly higher compared with the control and intervention groups.

Conclusion

These findings demonstrate that the upregulation of miR-330-3p can inhibit the expression of S100B.

Long non-coding RNAs in cardiac hypertrophy

Cardiac hypertrophy (CH) is generally considered adaptive responses that may occur after myocardial infarction, pressure overload, volume overload, inflammatory heart muscle disease, or idiopathic dilated cardiomyopathy, whereas long-term stimulation eventually leads to heart failure (HF). However, the current molecular mechanisms involved in CH are unclear. Recently, increasing evidences reveal that long non-coding RNAs (lncRNAs) play vital roles in CH. Different lncRNAs can promote or inhibit the pathological process of CH by different mechanisms, while the regulation of lncRNAs expression can improve CH. Thus, CH-related lncRNAs may become a novel field of research on CH.

Diagnostic and Prognostic Biomarkers for Myocardial Infarction

The incidence of myocardial infarction (MI) increases every year worldwide. Better diagnostic and prognostic biomarkers for clinical applications are the consistent pursuit of MI research. In addition to electrocardiogram, echocardiography, coronary angiography, etc., circulating biomarkers are essential for the diagnosis, prognosis, and treatment effect monitoring of MI patients. In this review, we assessed both strength and weakness of MI circulating biomarkers including: (1) originated from damaged myocardial tissues including current golden standard cardiac troponin, (2) released from non-myocardial tissues due to MI-induced systems reactions, and (3) preexisted in blood circulation before the occurrence of MI event. We also summarized newly reported MI biomarkers. We proposed that the biomarkers preexisting in blood circulation before MI incidents should be emphasized in research and development for MI prevention in near future.

Clinical and prognostic value of tumor volumetric parameters in melanoma patients undergoing 18F-FDG-PET/CT: a comparison with serologic markers of tumor burden and inflammation

BACKGROUND

To investigate the association of tumor volumetric parameters in melanoma patients undergoing 18F-FDG-PET/CT with serologic tumor markers and inflammatory markers and the role as imaging predictors for overall survival.

METHODS

A patient cohort with advanced melanoma undergoing 18F-FDG-PET/CT for planning metastasectomy between 04/2013 and 01/2015 was retrospectively included. The volumetric PET parameters whole-body MTV and whole-body TLG as well as the standard uptake value (SUV) peak were quantified using 50%-isocontour volumes of interests (VOIs) and then correlated with the serologic parameters lactate dehydrogenase (LDH), S-100 protein, c-reactive protein (CRP) and alkaline phosphatase (AP). PET parameters were dichotomized by their respective medians and correlated with overall survival (OS) after PET/CT. OS was compared between patients with or without metastases and increased or not-increased serologic parameters.

RESULTS

One hundred seven patients (52 female; 65 ± 13.1yr.) were included. LDH was strongly associated with MTV (rP = 0.73, p <  0.001) and TLG (rP = 0.62, p <  0.001), and moderately associated with SUVpeak (rP = 0.55, p <  0.001). S-100 protein showed a moderate association with MTV (rP = 0.54, p <  0.001) and TLG (rP = 0.48, p <  0.001) and a weak association with SUVpeak (rP = 0.42, p <  0.001). A strong association was observed between CRP and MTV (rP = 0.66, p <  0.001) and a moderate to weak association between CRP and TLG (rP = 0.53, p <  0.001) and CRP and SUVpeak (rP = 0.45, p <  0.001). For differentiation between patients with or without metastases, receiver operating characteristic (ROC) analysis revealed a cut-off value of 198 U/l for serum LDH (AUC 0.81, sensitivity 0.80, specificity 0.72). Multivariate analysis for OS revealed that both MTV and TLG were strong independent prognostic factors. TLG, MTV and SUVpeak above patient median were accompanied with significantly reduced estimated OS compared to the PET parameters below patient median (e.g. TLG: 37.1 ± 3.2 months vs. 55.9 ± 2.5 months, p <  0.001). Correspondingly, both elevated serum LDH and S-100 protein were accompanied with significantly reduced OS (36.5 ± 4.9 months and 37.9 ± 4.4 months) compared to normal serum LDH (49.2 ± 2.4 months, p = 0.01) and normal S-100 protein (49.0 ± 2.5 months, p = 0.01).

CONCLUSIONS

Tumor volumetric parameters in 18F-FDG-PET/CT serve as prognostic imaging biomarkers in patients with advanced melanoma which are associated with established serologic tumor markers and inflammatory markers.

Interactions Among Regulatory Non-coding RNAs Involved in Cardiovascular Diseases

Non-coding RNAs (ncRNAs) are important regulatory players in human cells that have been shown to modulate different cellular processes and biological functions through controlling gene expression, being also involved in pathological conditions such as cardiovascular diseases. Among them, long non-coding RNAs (lncRNAs) and circular (circRNAs) could act as competing endogenous RNAs (ceRNAs) sequestering other ncRNAs. This entangled network of interactions has been reported to trigger the decay of the targeted ncRNAs having important roles in gene regulation. Growing evidences have been demonstrated that the regulatory mechanism underlying the crosstalk between different ncRNA species, namely lncRNAs, circRNAs and miRNAs has also an important role in the pathophysiological processes of cardiovascular diseases. In this chapter, the main regulatory relationship among lncRNAs, circRNAs and miRNAs were summarized and their role in the control and development of cardiovascular diseases was highlighted.

The long noncoding RNA XIST protects cardiomyocyte hypertrophy by targeting miR-330-3p

Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are implicated in numerous kinds of cardiovascular diseases, and their vital role in regulating cardiac hypertrophy still needs to be explored. In this study, we demonstrated that lncRNA X-inactive specific transcript (XIST) was upregulated in hypertrophic cardiac of mice and phenylephrine (PE)-treated cardiomyocytes. Next, we observed that inhibition of XIST induced hypertrophic response of cardiomyocyte and overexpression of XIST attenuated cardiomyocyte hypertrophy induced by PE. Furthermore, through online predictive tools and functional experiments, we demonstrated that XIST and S100B were targets of miR-330-3p. XIST and miR-330-3p suppressed each other in a reciprocal way in cardiomyocytes. Additionally, XIST promoted S100B expression through harboring the complementary binding sites with miR-330-3p, eventually prevented cardiac hypertrophy. In conclusion, our findings revealed a novel molecular mechanism that XIST/miR-330-3p/S100B pathway modulates the progression of cardiomyocyte hypertrophy.

Correlation between Amitriptyline-Induced Cardiotoxic Effects and Cardiac S100b Protein in Isolated Rat Hearts

BACKGROUND

Amitriptyline is an important cause of mortality due to its cardiovascular toxicity.

AIMS

To investigate the changes in levels of cardiac S100b protein on amitriptyline-induced cardiotoxicity and also to examine the correlation between amitriptyline-induced cardiotoxic effects and cardiac S100b protein in an isolated rat heart model.

STUDY DESIGN

Animal experimentation, isolated heart model.

METHODS

After a stabilization period, isolated hearts were randomized to two groups (n=5 and n=7). In the control group, isolated hearts were subjected to an infusion of 5% dextrose for 60 minutes. In the amitriptyline group, 5.5×10^-5 M amitriptyline was infused for 60 minutes to achieve amitriptyline toxicity. After the infusion period, heart tissues were removed for histological examination.

RESULTS

In comparison to control treatment, amitriptyline infusion decreased left ventricular developed pressure (LVDP), dp/dtmax and heart rate (HR) and significantly prolonged QRS duration (p<0.05). The semiquantitative scores for S100b protein levels in amitriptyline-infused hearts were higher than in the control group (p<0.01). At the end of the experiment, in the amitriptyline-infused group, significant correlations were found between LVDP and S100b protein scores (r=-0.807, p=0.003) and between QRS duration and S100b protein scores (r=0.859, p=0.001).

CONCLUSION

Our results indicate that the S100b protein may be a helpful indicator or biomarker in studying the cardiotoxic effects of amitriptyline.

Biomarker value and pitfalls of serum S100B in the follow-up of high-risk melanoma patients

BACKGROUND AND OBJECTIVES

Serum levels of S100B are standard in monitoring advanced malignant melanoma patients in order to discriminate progressive from non-progressive disease. False-positive results lead to distress among patients and increase the amount of cost-intensive diagnostics. We therefore analyzed reported comorbid diseases as putative sources of excessive S100B release.

PATIENTS AND METHODS

Here, we report a single-center experience on serum S100B levels in 2,664 blood samples from 1,113 stage IB to IV melanoma patients (AJCC) who presented for follow-up examinations over a period of 24 months.

RESULTS

Overall, 295 (11%) of patients developed disease progression. In patients with a high tumor load, the rate of false-negative results was 30/185 (16%). The rate of false-positive results was 247/2369 (12%). One hundred and six false-positive results (69%) compared to 46 true-positive results (31%) were found in patients with cardiovascular diseases such as arrhythmia (50/32) or previous myocardial infarction (22/14). Moreover, obesity (85/14), liver cirrhosis (31/10), migraine (18/2), chronic kidney disease (13/2), and previous stroke (11/1) were found to be associated with false-positive S100B levels.

CONCLUSIONS

Serum S100B is a useful quantitative biomarker in routine follow-up of high-risk melanoma patients. While false-negative results are frequent in patients with low tumor load, false-positive results are associated with several comorbid diseases and warrant careful reevaluation.

Evaluating biomarkers in melanoma

The incidence of cutaneous melanoma has more than doubled over the last decades making it one of the fastest rising cancers worldwide. Improved awareness and early detection of malignant moles now permit earlier diagnosis aiming to decrease the likelihood of recurrence. However, it is difficult to identify those patients initially diagnosed with localized melanoma who subsequently develop metastatic disease. For this group, prognosis remains poor and clinical outcomes are variable and challenging to predict. Considerable efforts have focused on the search for novel prognostic tools, with numerous markers evaluated in the circulation and in tumor lesions. The most reliable predictors of patient outcome are the clinical and histological features of the primary tumor such as Breslow thickness, ulceration status, and mitotic rate. Elevated serum levels of the enzyme lactate dehydrogenase, likely to indicate active metastatic disease, are also routinely used to monitor patients. The emergence of novel immune and checkpoint antibody treatments for melanoma and increasing appreciation of key roles of the immune system in promoting or halting cancer progression have focused attention to immunological biomarkers. Validation of the most promising of these may have clinical applications in assisting prognosis, assessing endpoints in therapy, and monitoring responses during treatment.

Serum levels of protein S100B predict intracranial lesions in mild head injury

OBJECTIVES

This study was aimed to assess whether serum S100B levels at emergency department admission can be used to omit unnecessary computed tomography (CT) in patients with minor head injury (MHI).

DESIGN AND METHODS

Sixty consecutive patients with recent MHI were included in this study. Serum S100B measurement and CT scanning were performed in all patients within 3h from head injury.

RESULTS

A positive CT scan was present in 20 out of 60 subjects. Significantly higher values of protein S100B were found in CT positive than in CT negative patients (1.35 versus 0.48 μg/L; p<0.001). The area under the ROC curve for protein S100B was highly significant (AUC 0.80; p<0.001) and a S100B cut-off value of 0.38 μg/L displayed 100% sensitivity and 58% specificity.

CONCLUSIONS

Serum S100-B levels might allow to omit unnecessary CT in patients with pure MHI, thus reducing radiation exposure and saving healthcare resources.

Adipocytes as an Important Source of Serum S100B and Possible Roles of This Protein in Adipose Tissue

Adipocytes contain high levels of S100B and in vitro assays indicate a modulated secretion of this protein by hormones that regulate lipolysis, such as glucagon, adrenaline, and insulin. A connection between lipolysis and S100B release has been proposed but definitive evidence is lacking. Although the biological significance of extracellular S100B from adipose tissue is still unclear, it is likely that this tissue might be an important source of serum S100B in situations related, or not, to brain damage. Current knowledge does not preclude the use of this protein in serum as a marker of brain injury or astroglial activation, but caution is recommended when discussing the significance of changes in serum levels where S100B may function as an adipokine, a neurotrophic cytokine, or an alarmin.