Low-grade inflammation and tryptophan-kynurenine pathway activation are associated with adverse cardiac remodeling in primary hyperparathyroidism: the EPATH trial

Association between primary hyperparathyroidism and cardiovascular outcomes: A systematic review and meta-analysis

BACKGROUND

Excess parathyroid hormone (PTH) is associated with an increased risk of cardiovascular disease (CVD).

PURPOSE

We aimed to evaluate the correlation between primary hyperparathyroidism (PHPT) and CVD or cardiovascular (CV) death.

DATA SOURCES

Comprehensive searches of PubMed, Embase and ClinicalTrials.gov until May 20, 2023 with the following keywords: "primary hyperparathyroidism," "cardiovascular disease," and "mortality."

STUDY SELECTIONS

Cohort studies and randomized controlled trials comparing PHPT patients to the general population and those who had received parathyroidectomy (PTX) to those who did not.

DATA EXTRACTION

Three investigators independently extracted data and assessed study quality.

DATA SYNTHESIS

Eleven cohort studies and one randomized controlled trial were identified, including 264,227 PHPT patients with or without PTX, and the average age reported in the studies was 62 years. PHPT was associated with a higher risk of total death (RR 1.39 [95 % confidence interval (CI) 1.23-1.57) and CV death (RR 1.61 [95 % CI 1.47-1.78]) than the general population. However, there was no significant difference in CVD risk between patients with PHPT and the general population (RR 1.73 [95 % CI 0.87-3.47]). When compared to patients without PTX, PTX had a lower risk of CV death (RR 0.75 [95 % CI 0.71-0.80]), total death (RR 0.64 [95 % CI 0.60-0.70]) and CVD (RR 0.92 [95 % CI 0.90-0.94]).

LIMITATION

High heterogeneity among the included articles, and most of them were retrospective and older studies.

CONCLUSIONS

PHPT was associated with higher risk of total death and CV death while PTX was associated with lower risk of total death, CV death, and CVD.

Identification of immune-related genes and small-molecule drugs in hypertension-induced left ventricular hypertrophy based on machine learning algorithms and molecular docking

Background

Left ventricular hypertrophy (LVH) is a common consequence of hypertension and can lead to heart failure. The immune response plays an important role in hypertensive LVH; however, there is no comprehensive method to investigate the mechanistic relationships between immune response and hypertensive LVH or to find novel therapeutic targets. This study aimed to screen hub immune-related genes involved in hypertensive LVH as well as to explore immune target-based therapeutic drugs.

Materials and methods

RNA-sequencing data from a mouse model generated by angiotensin II infusion were subjected to weighted gene co-expression network analysis (WGCNA) to identify core expression modules. Machine learning algorithms were applied to screen immune-related LVH characteristic genes. Heart structures were evaluated by echocardiography and cardiac magnetic resonance imaging (CMRI). Validation of hub genes was conducted by RT-qPCR and western blot. Using the Connectivity Map database and molecular docking, potential small-molecule drugs were explored.

Results

A total of 1215 differentially expressed genes were obtained, most of which were significantly enriched in immunoregulation and collagen synthesis. WGCNA and multiple machine learning strategies uncovered six hub immune-related genes (Ankrd1, Birc5, Nuf2, C1qtnf6, Fcgr3, and Cdca3) that may accurately predict hypertensive LVH diagnosis. Immune analysis revealed that fibroblasts and macrophages were closely correlated with hypertensive LVH, and hub gene expression was significantly associated with these immune cells. A regulatory network of transcription factor-mRNA and a ceRNA network of miRNA-lncRNA was established. Notably, six hub immune-related genes were significantly increased in the hypertensive LVH model, which were positively linked to left ventricle wall thickness. Finally, 12 small-molecule compounds with the potential to reverse the high expression of hub genes were ruled out as potential therapeutic agents for hypertensive LVH.

Conclusion

This study identified and validated six hub immune-related genes that may play essential roles in hypertensive LVH, providing new insights into the potential pathogenesis of cardiac remodeling and novel targets for medical interventions.

Metabolic profile of blood serum in experimental arterial hypertension

The etiology of essential hypertension is intricate, since it employs simultaneously various body systems related to the regulation of blood pressure in one way or another: the sympathetic nervous system, renin-angiotensin-aldosterone and hypothalamic-pituitary-adrenal systems, renal and endothelial mechanisms. The pathogenesis of hypertension is influenced by a variety of both genetic and environmental factors, which determines the heterogeneity of the disease in human population. Hence, there is a need to perform research on experimental models - inbred animal strains, one of them being ISIAH rat strain, which is designed to simulate inherited stress-induced arterial hypertension as close as possible to primary (or essential) hypertension in humans. To determine specific markers of diseases, various omics technologies are applied, including metabolomics, which makes it possible to evaluate the content of low-molecular compounds - amino acids, lipids, carbohydrates, nucleic acids fragments - in biological samples available for clinical analysis (blood and urine). We analyzed the metabolic profile of the blood serum of male ISIAH rats with a genetic stress-dependent form of arterial hypertension in comparison with the normotensive WAG rats. Using the method of nuclear magnetic resonance spectroscopy (NMR spectroscopy), 56 metabolites in blood serum samples were identified, 18 of which were shown to have significant interstrain differences in serum concentrations. Statistical analysis of the data obtained showed that the hypertensive status of ISIAH rats is characterized by increased concentrations of leucine, isoleucine, valine, myo-inositol, isobutyrate, glutamate, glutamine, ornithine and creatine phosphate, and reduced concentrations of 2-hydroxyisobutyrate, betaine, tyrosine and tryptophan. Such a ratio of the metabolite concentrations is associated with changes in the regulation of glucose metabolism (metabolic markers - leucine, isoleucine, valine, myo-inositol), of nitric oxide synthesis (ornithine) and catecholamine pathway (tyrosine), and with inflammatory processes (metabolic markers - betaine, tryptophan), all of these changes being typical for hypertensive status. Thus, metabolic profiling of the stress-dependent form of arterial hypertension seems to be an important result for a personalized approach to the prevention and treatment of hypertensive disease.

Stress and Kynurenine-Inflammation Pathway in Major Depressive Disorder

Major depressive disorder (MDD) is one of the most prevalent disorders and causes severe damage to people's quality of life. Lifelong stress is one of the major villains in triggering MDD. Studies have shown that both stress and MDD, especially the more severe conditions of the disorder, are associated with inflammation and neuroinflammation and the relationship to an imbalance in tryptophan metabolism towards the kynurenine pathway (KP) through the enzymes indoleamine-2,3-dioxygenase (IDO), which is mainly stimulated by pro-inflammatory cytokines and tryptophan-2,3-dioxygenase (TDO) which is activated primarily by glucocorticoids. Considering that several pathophysiological mechanisms of MDD underlie or interact with biological processes from KP metabolites, this chapter addresses and discusses the function of these mechanisms. Activities triggered by stress and the hypothalamic-pituitary-adrenal (HPA) axis and immune and inflammatory processes, in addition to epigenetic phenomena and the gut-brain axis (GBA), are addressed. Finally, studies on the function and mechanisms of physical exercise in the KP metabolism and MDD are pointed out and discussed.

Tryptophan was metabolized into beneficial metabolites against coronary heart disease or prevented from producing harmful metabolites by the in vitro drug screening model based on Clostridium sporogenes

In our previous study of 2,130 Chinese patients with coronary heart disease (CHD), we found that tryptophan (TRP) metabolites contributed to elevated risks of death. Many TRP-derived metabolites require the participation of intestinal bacteria to produce, and they play an important role in the pathogenesis of metabolic diseases such as CHD. So it is necessary to metabolize TRP into beneficial metabolites against CHD or prevent the production of harmful metabolites through external intervention. Indole-3-butyric acid (IBA) may be a key point of gut microbiota that causes TRP metabolism disorder and affects major adverse cardiovascular events in CHD. Therefore, this study aimed to develop a method based on in vitro culture bacteria to evaluate the effects of IBA on specific microbial metabolites quickly. We detected the concentrations of TRP and its metabolites in 11 bacterial strains isolated from feces using liquid chromatography–mass spectrometry, and selected Clostridium sporogenes as the model strain. Then, IBA was used in our model to explore its effect on TRP metabolism. Results demonstrated that the optimal culture conditions of C. sporogenes were as follows: initial pH, 6.8; culture temperature, 37°C; and inoculum amount, 2%. Furthermore, we found that IBA increases the production of TRP and 5-HIAA by intervening TRP metabolism, and inhibits the production of KYNA. This new bacteria-specific in vitro model provides a flexible, reproducible, and cost-effective tool for identifying harmful agents that can decrease the levels of beneficial TRP metabolites. It will be helpful for researchers when developing innovative strategies for studying gut microbiota.

Plasma metabolomics provides new insights into the relationship between metabolites and outcomes and left ventricular remodeling of coronary artery disease

BACKGROUND

Coronary artery disease (CAD) is a metabolically perturbed pathological condition. However, the knowledge of metabolic signatures on outcomes of CAD and their potential causal effects and impacts on left ventricular remodeling remains limited. We aim to assess the contribution of plasma metabolites to the risk of death and major adverse cardiovascular events (MACE) as well as left ventricular remodeling.

RESULTS

In a prospective study with 1606 Chinese patients with CAD, we have identified and validated several independent metabolic signatures through widely-targeted metabolomics. The predictive model respectively integrating four metabolic signatures (dulcitol, β-pseudouridine, 3,3',5-Triiodo-L-thyronine, and kynurenine) for death (AUC of 83.7% vs. 76.6%, positive IDI of 0.096) and metabolic signatures (kynurenine, lysoPC 20:2, 5-methyluridine, and L-tryptophan) for MACE (AUC of 67.4% vs. 59.8%, IDI of 0.068) yielded better predictive value than trimethylamine N-oxide plus clinical model, which were successfully applied to predict patients with high risks of death (P = 0.0014) and MACE (P = 0.0008) in the multicenter validation cohort. Mendelian randomisation analysis showed that 11 genetically inferred metabolic signatures were significantly associated with risks of death or MACE, such as 4-acetamidobutyric acid, phenylacetyl-L-glutamine, tryptophan metabolites (kynurenine, kynurenic acid), and modified nucleosides (β-pseudouridine, 2-(dimethylamino) guanosine). Mediation analyses show that the association of these metabolites with the outcomes could be partly explained by their roles in promoting left ventricular dysfunction.

CONCLUSIONS

This study provided new insights into the relationship between plasma metabolites and clinical outcomes and its intermediate pathological process left ventricular dysfunction in CAD. The predictive model integrating metabolites can help to improve the risk stratification for death and MACE in CAD. The metabolic signatures appear to increase death or MACE risks partly by promoting adverse left ventricular dysfunction, supporting potential therapeutic targets of CAD for further investigation.

Kynurenine Pathway Metabolites as Potential Clinical Biomarkers in Coronary Artery Disease

Coronary artery disease (CAD) is one of the leading cause of mortality worldwide. Several risk factors including unhealthy lifestyle, genetic background, obesity, diabetes, hypercholesterolemia, hypertension, smoking, age, etc. contribute to the development of coronary atherosclerosis and subsequent coronary artery disease. Inflammation plays an important role in coronary artery disease development and progression. Pro-inflammatory signals promote the degradation of tryptophan via the kynurenine pathway resulting in the formation of several immunomodulatory metabolites. An unbalanced kynurenic pathway has been implicated in the pathomechanisms of various diseases including CAD. Significant improvements in detection methods in the last decades may allow simultaneous measurement of multiple metabolites of the kynurenine pathway and such a thorough analysis of the kynurenine pathway may be a valuable tool for risk stratification and determination of CAD prognosis. Nevertheless, imbalance in the activities of different branches of the kynurenine pathway may require careful interpretation. In this review, we aim to summarize clinical evidence supporting a possible use of kynurenine pathway metabolites as clinical biomarkers in various manifestations of CAD.

Biomarkers of inflammation and left ventricular remodelling in psoriasis patients treated with infliximab

Objective: Psoriasis is an immune mediated disorder associated with T cell activation and cardiovascular disease (CVD). We explored the association of inflammation with left ventricular (LV) remodelling in psoriasis patients receiving treatment with the tumour necrosis factor-α (TNF-α) blocker infliximab. Methods: Psoriasis patients (n = 47, age 47 ± 14 years, 66% men) and 99 control subjects without psoriasis (age 47 ± 11 years, 72% men) were examined by echocardiography in a cross-sectional study. LV remodelling was assessed by LV mass index for height in the allometric power of 2.7. Serum concentrations of C-reactive protein (CRP), serum amyloid A (SAA), neopterin, kynurenine:tryptophan ratio (KTR) and the pyridoxic acid ratio (PAr) index were measured. Results: Serum concentration of neopterin (p = .007) was higher in psoriasis patients, while the other inflammatory biomarkers had similar levels. LV mass index was lower in patients than controls (35.6 ± 9.6 g/m^2.7 vs. 40.3 ± 9.8 g/m^2.7, p = .008). In the total study population, serum SAA (β = 0.18, p = .02), KTR (β = 0.20, p = .02) and the PAr index (β = 0.26, p = .002) were all associated with higher LV mass index independent of age, sex, body mass index, hypertension, smoking, renal function and psoriasis. Also in psoriasis patients, higher SAA level (β = 0.34, p = .02), KTR (β = 0.32, p = .02) and the PAr index (β = 0.29, p = .05) were associated with higher LV mass index independent of body mass index, hypertension and diabetes. Conclusion: Higher levels of the inflammatory biomarkers SAA, KTR and the PAr index were associated with greater LV mass index in psoriasis patients, indicating a role of chronic inflammation in LV remodelling evident even during treatment with TNF-α blockers.

Serum Inflammation-based Scores in Endocrine Tumors

CONTEXT

Serum inflammation-based scores reflect systemic inflammatory response and/or patients' nutritional status, and may predict clinical outcomes in cancer. While these are well-described and increasingly used in different cancers, their clinical usefulness in the management of patients with endocrine tumors is less known.

EVIDENCE ACQUISITION

A comprehensive PubMed search was performed using the terms "endocrine tumor," "inflammation," "serum inflammation-based score," "inflammatory-based score," "inflammatory response-related scoring," "systemic inflammatory response markers," "neutrophil-to-lymphocyte ratio," "neutrophil-to-platelet ratio," "lymphocyte-to-monocyte ratio," "Glasgow prognostic score," "neutrophil-platelet score," "Systemic Immune-Inflammation Index," and "Prognostic Nutrition Index" in clinical studies.

EVIDENCE SYNTHESIS

The neutrophil-to-lymphocyte ratio and the platelet-to-lymphocyte ratio are the ones most extensively investigated in patients with endocrine tumors. Other scores have also been considered in some studies. Several studies focused in finding whether serum inflammatory biomarkers may stratify the endocrine tumor patients' risk and detect those at risk for developing more aggressive and/or refractory disease, particularly after endocrine surgery.

CONCLUSIONS

In this review, we summarize the current knowledge on the different serum inflammation-based scores and their usefulness in predicting the phenotype, clinical aggressiveness, and disease outcomes and prognosis in patients with endocrine tumors. The value of such serum inflammation-based scores in the management of patients with endocrine tumors has been emerging over the last decade. However, further research is necessary to establish useful markers and their cut-offs for routine clinical practice for individual diseases.

Does Parathyroidectomy Affect the Neutrophil/Lymphocyte Ratio, a Systemic Inflammatory Marker?

Introduction

Primary hyperparathyroidism (PHPT) is an endocrinological disorder associated with increased systemic inflammation. This study aimed to examine the changes in the neutrophil/lymphocyte ratio (NLR), serum parathormone, serum corrected calcium, serum phosphate, and white blood cell (WBC) count ​​in patients with PHPT before and after parathyroidectomy.

Methods

A total of 37 patients who underwent successful parathyroidectomy for PHPT were included in the study. NLR, serum parathormone, serum corrected calcium, serum phosphate, and WBC count ​​were compared before parathyroidectomy and at the sixth postoperative month.

Results

The difference in the NLR, serum parathormone, serum corrected calcium, and serum phosphate values ​​before and after parathyroidectomy was statistically significant (p=0.019, p<0.001, p<0.001, and p<0.001, respectively), but there was no significant difference in the WBC count ​​(p=0.314). The correlation analysis performed before parathyroidectomy revealed a significant positive correlation between NLR and serum parathormone (r=0.519, p=0.001), serum corrected calcium (r=0.390, p=0.017) and WBC count (r=0.531, p=0.001), and a significant negative correlation between NLR and serum phosphate (r=-0.331).

Conclusion

In patients with PHPT, successful parathyroidectomy results in a decrease in NLR. Increased systemic inflammation in patients with PHPT can be reduced following parathyroidectomy.

Identification of biomarkers for essential hypertension based on metabolomics

AIM

Essential hypertension (EH) is one of the most important public health problems worldwide. However, the pathogenesis of EH is unclear and early diagnostic methods are lacking. Metabolomics demonstrates great potential for biomarker discovery and the mechanistic exploration of metabolic diseases.

DATA SYNTHESIS

This review included human and animal metabolomics studies related to EH in the PubMed and Web of Science databases between February 1996 and May 2020. The study designs, EH standards, and reported metabolic biomarkers were systematically examined and compared. The pathway analysis was conducted through the online software MetaboAnalyst 4.0. Twenty-two human studies and fifteen animal studies were included in this systematic review. There were many frequently reported biomarkers with consistent trends (e.g., pyruvate, lactic acid, valine, and tryptophan) in human and animal studies, and thus had potential as biomarkers of EH. In addition, several shared metabolic pathways, including alanine, aspartate, and glutamate metabolism, aminoacyl-tRNA biosynthesis, and arginine biosynthesis, were identified in human and animal metabolomics studies. These biomarkers and pathways, closely related to insulin resistance, the inflammatory state, and impaired nitric oxide production, were demonstrated to contribute to EH development.

CONCLUSIONS

This study summarized valuable metabolic biomarkers and pathways that could offer opportunities for the early diagnosis or prediction of EH and the discovery of the metabolic mechanisms of EH.

Effects of tryptophan, serotonin, and kynurenine on ischemic heart diseases and its risk factors: a Mendelian Randomization study

BACKGROUND/OBJECTIVES

Tryptophan is an essential amino acid that must be obtained from dietary items, such as dairy products, eggs, nuts, legumes, and grains, which are rich in tryptophan. It has also been suggested as a dietary supplement to improve mental health. Observationally plasma tryptophan is inversely associated with ischemic heart disease (IHD), however, its main metabolites, serotonin, and kynurenine are positively associated with IHD, which makes the effects of tryptophan difficult to infer. This study aimed to obtain less-confounded estimates of the associations of tryptophan and physiologically related factors (serotonin and kynurenine) with IHD, its risk factors and depression.

SUBJECTS/METHODS

We used a two-sample Mendelian Randomization study design. We used genetic instruments independently associated with tryptophan, serotonin, and kynurenine metabolites applied to a meta-analysis of the UK Biobank SOFT CAD study with the CARDIoGRAMplusC4D consortium (cases n ≤ 76,014 and controls n ≤ 264,785), and other consortia for risk factors including diabetes, lipids, and blood pressure, as well as for depression. We combined genetic variant-specific estimates using inverse variance weighting, with MR-Egger, the weighted median and MR-PRESSO as sensitivity analyses.

RESULTS

Tryptophan and serotonin were not associated with IHD. Kynurenine was nominally and positively associated with IHD (odds ratio 1.57 per standard deviation, 95% confidence interval 1.05-2.33) but not after correction for multiple comparisons. Associations with IHD risk factors and depression were null.

CONCLUSIONS

We cannot exclude the possibility that one of the main metabolites of tryptophan, kynurenine, might be positively associated with IHD. Further studies are needed to confirm any association and underlying mechanism.

Left Ventricular Hypertrophy: Roles of Mitochondria CYP1B1 and Melatonergic Pathways in Co-Ordinating Wider Pathophysiology

Left ventricular hypertrophy (LVH) can be adaptive, as arising from exercise, or pathological, most commonly when driven by hypertension. The pathophysiology of LVH is consistently associated with an increase in cytochrome P450 (CYP)1B1 and mitogen-activated protein kinases (MAPKs) and a decrease in sirtuins and mitochondria functioning. Treatment is usually targeted to hypertension management, although it is widely accepted that treatment outcomes could be improved with cardiomyocyte hypertrophy targeted interventions. The current article reviews the wide, but disparate, bodies of data pertaining to LVH pathoetiology and pathophysiology, proposing a significant role for variations in the N-acetylserotonin (NAS)/melatonin ratio within mitochondria in driving the biological underpinnings of LVH. Heightened levels of mitochondria CYP1B1 drive the ‘backward’ conversion of melatonin to NAS, resulting in a loss of the co-operative interactions of melatonin and sirtuin-3 within mitochondria. NAS activates the brain-derived neurotrophic factor receptor, TrkB, leading to raised trophic signalling via cyclic adenosine 3′,5′-monophosphate (cAMP)-response element binding protein (CREB) and the MAPKs, which are significantly increased in LVH. The gut microbiome may be intimately linked to how stress and depression associate with LVH and hypertension, with gut microbiome derived butyrate, and other histone deacetylase inhibitors, significant modulators of the melatonergic pathways and LVH more generally. This provides a model of LVH that has significant treatment and research implications.

Association between neutrophil-to-lymphocyte ratio and parathyroid hormone in patients with primary hyperparathyroidism

INTRODUCTION

Primary hyperparathyroidism (PHPT) is associated with adverse cardiovascular outcomes which may result from an increase in systemic inflammation. Previously we have shown that serum parathyroid hormone (PTH) levels are independently associated with inflammatory indicators. The neutrophil-to-lymphocyte ratio (NLR) is an inexpensive, widely available marker of inflammation. In the present study, we aimed to assess the longitudinal changes in NLR before and after parathyroidectomy.

MATERIAL AND METHODS

This retrospective study included 95 patients diagnosed with PHPT who underwent parathyroidectomy between 2006 and 2016. Follow-up complete blood counts were available in 31 patients.

RESULTS

At diagnosis, 43 (45%) patients presented with overt clinical symptoms and had higher serum calcium and PTH levels. Preoperative NLR was positively correlated with total white blood cell count (p = 0.001), serum calcium (p = 0.001), and PTH level (p = 0.013). The NLR was not associated with sex, age, comorbidities, or parathyroid weight. Among patients who were cured of PHPT, the median NLR decreased from 2.26 to 1.77 after parathyroidectomy (p = 0.037). There was no difference in hemoglobin, total white blood cells, or platelet count before and after surgery.

CONCLUSIONS

We found a positive correlation of preoperative NLR with calcium and PTH levels in PHPT patients. After curative parathyroidectomy, NLR modestly decreased without changes in other hematological parameters.