Understanding mechanisms of hypertension in systemic lupus erythematosus

Leptin antagonism attenuates hypertension and renal injury in an experimental model of autoimmune disease

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that is characterized by B- and T-lymphocyte dysfunction and altered cytokine production, including elevated levels of the adipocytokine leptin. Leptin has various immunomodulatory properties, including promoting the expansion of proinflammatory T lymphocytes and the proliferation and survival of B cells. In the present study, we hypothesized that leptin antagonism would improve B- and T-cell dysfunction and attenuate hypertension in an experimental model of SLE, the NZBWF1 mouse. To test this hypothesis, 28-week-old female control and SLE mice were administered 5 mg/kg of murine leptin superantagonist (LA) or vehicle via ip injection every other day for four weeks. Analysis of peripheral blood immune cell populations showed no changes in total CD45R+ B and CD3+ T cell percentages after treatment with LA. However, SLE mice treated with LA had an improved CD4/CD8 ratio and decreased CD3+CD4-CD8- double negative (DN) T cells. Blood pressure was higher in SLE than in control, and treatment with LA decreased blood pressure in SLE mice. Treatment with LA also delayed the onset of albuminuria and decreased glomerulosclerosis in SLE mice. Renal immune cell infiltration was significantly higher in SLE mice as compared with control, but LA treatment was associated with decreased levels of renal CD4+ T cells. In conclusion, these data suggest that leptin plays a pathogenic role in the development of hypertension in SLE, in part, by promoting the expansion of inflammatory DN T cells and the infiltration of T cells into the kidneys.

Role of Inflammatory Processes in the Brain-Body Relationship Underlying Hypertension

PURPOSE OF REVIEW

Essential hypertension is a huge health problem that significantly impacts worldwide population in terms of morbidity and mortality. Idiopathic in its nature, elevated blood pressure results from a complex interaction between polygenic components and environmental and lifestyle factors. The constant growth in the burden of hypertension is at odds with expectations, considering the availability of therapeutic strategies. Hence, there is an endless need to further investigate the complexity of factors contributing to blood pressure elevation.

RECENT FINDINGS

Recent data indicate that bidirectional interactions between the nervous system and the immune system alter inflammation in the brain and periphery, contributing to chronic hypertension. These findings indicate that the nervous system is both a direct driver of hypertension and also a target of feedback that often elevates blood pressure further. Similarly, the immune system is both target and driver of the blood pressure increases. The contributions of the feedback loops among these systems appear to play an important role in hypertension. Together, recent mechanistic studies strongly suggest that the interactions among the brain, immune system, and inflammation affect the participation of each system in the pathogenesis of hypertension, and thus, all of these systems must be considered in concert to gain a full appreciation of the development and potential treatments of hypertension.

Targeting the gut microbiota with dietary fibers: a novel approach to prevent the development cardiovascular complications linked to systemic lupus erythematosus in a preclinical study

This study is to investigate whether dietary fiber intake prevents vascular and renal damage in a genetic mouse model of systemic lupus erythematosus (SLE), and the contribution of gut microbiota in the protective effects. Female NZBWF1 (SLE) mice were treated with resistant-starch (RS) or inulin-type fructans (ITF). In addition, inoculation of fecal microbiota from these experimental groups to recipient normotensive female C57Bl/6J germ-free (GF) mice was performed. Both fiber treatments, especially RS, prevented the development of hypertension, renal injury, improved the aortic relaxation induced by acetylcholine, and the vascular oxidative stress. RS and ITF treatments increased the proportion of acetate- and butyrate-producing bacteria, respectively, improved colonic inflammation and integrity, endotoxemia, and decreased helper T (Th)17 proportion in mesenteric lymph nodes (MLNs), blood, and aorta in SLE mice. However, disease activity (splenomegaly and anti-ds-DNA) was unaffected by both fibers. T cell priming and Th17 differentiation in MLNs and increased Th17 infiltration was linked to aortic endothelial dysfunction and hypertension after inoculation of fecal microbiota from SLE mice to GF mice, without changes in proteinuria and autoimmunity. All these effects were lower in GF mice after fecal inoculation from fiber-treated SLE mice. In conclusion, these findings support that fiber consumption prevented the development of hypertension by rebalancing of dysfunctional gut-immune system-vascular wall axis in SLE.

Metabolic Modulators in Cardiovascular Complications of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multifactorial disorder with contributions from hormones, genetics, and the environment, predominantly affecting young women. Cardiovascular disease is the primary cause of mortality in SLE, and hypertension is more prevalent among SLE patients. The dysregulation of both innate and adaptive immune cells in SLE, along with their infiltration into kidney and vascular tissues, is a pivotal factor contributing to the cardiovascular complications associated with SLE. The activation, proliferation, and differentiation of CD4+ T cells are intricately governed by cellular metabolism. Numerous metabolic inhibitors have been identified to target critical nodes in T cell metabolism. This review explores the existing evidence and knowledge gaps concerning whether the beneficial effects of metabolic modulators on autoimmunity, hypertension, endothelial dysfunction, and renal injury in lupus result from the restoration of a balanced immune system. The inhibition of glycolysis, mitochondrial metabolism, or mTORC1 has been found to improve endothelial dysfunction and prevent the development of hypertension in mouse models of SLE. Nevertheless, limited information is available regarding the potential vasculo-protective effects of drugs that act on immunometabolism in SLE patients.

Weaning Maintenance Therapy in Lupus Nephritis: For Whom, When, and How?

Lupus nephritis (LN) is one of the main determinants of the severity of systemic lupus erythematosus (SLE). LN flares can lead to organ damage with chronic kidney disease (CKD) or even end-stage kidney disease (ESKD) and impair patients' survival. The "treat-to-target" strategy, which aims at obtaining and maintaining remission or low disease activity of SLE to alleviate symptoms and prevent organ damage, also refers to the control of residual activity in the kidney. But damage in SLE can also come from treatments, and toxicities related to long-term use of treatments should be prevented. This may contribute to the frequent nonadherence in patients with SLE. The de-escalation or even weaning of treatments whenever possible, or "think-to-untreat" (T2U) strategy, is to be considered in patients with LN. This possibility of treatment weaning in LN was explored in retrospective cohorts, on the basis of long-term clinical remission. It was also proposed prospectively with a kidney-biopsy-based approach, combining clinical and pathologic remission to secure treatment weaning. The WIN-Lupus trial was the first randomized controlled trial comparing the continuation to the discontinuation of maintenance immunosuppressive therapy (IST) after 2 to 3 years in patients with LN in remission. It showed a higher risk of severe SLE flares in patients who discontinued treatment, but also a possibility of weaning without flare in some patients, who need to be better identified. We propose here a narrative review of the available literature on the weaning of treatment in LN and discuss how to secure a T2U strategy.

Renal TLR-7/TNF-α pathway as a potential female-specific mechanism in the pathogenesis of autoimmune-induced hypertension

Hypertension is prevalent in patients with systemic lupus erythematosus (SLE). The goal of the current study is to track the pathogenesis of hypertension and renal injury in SLE, identify contributory mechanisms, and highlight differences in disease development among sexes. Mean arterial pressure was measured in conscious male and female SLE (NZBWF1) and control (NZW) mice at 34-35 wk of age using indwelling arterial catheters. Measures of renal injury, renal inflammation, and renal hemodynamics were used to monitor the potential contributors to latent sex differences. Both male and female SLE mice were hypertensive at 35 wk of age, and the hypertension was linked to renal injury in females, but not in males. A known contributor of renal pathology in SLE, Toll-like receptor (TLR)-7, and its downstream effector, the proinflammatory cytokine tumor necrosis factor (TNF)-α, were lower in male SLE mice than in females. Male SLE mice also had higher glomerular filtration rate (GFR) and lower renal vascular resistance (RVR) than females. Our data suggest that although hypertension in female SLE mice is associated with renal mechanisms, hypertension in male SLE mice may develop independent of renal changes. Future studies will continue to dissect sex-specific factors that should be considered when treating patients with hypertension with underlying chronic inflammation and/or autoimmunity.NEW & NOTEWORTHY There is a high prevalence of hypertension in male and female SLE; however, male SLE mice are hypertensive without renal involvement. The development of hypertension in female SLE mice is renocentric and strongly associated with injurious renal mechanisms like the TLR-7→TNF-α pathway. This clear difference in the pathogenesis among the sexes could have a significant impact on how we treat patients with hypertension with underlying chronic autoimmune/inflammatory diseases.

Dual Costimulatory and Coinhibitory Targeting with a Hybrid Fusion Protein as an Immunomodulatory Therapy in Lupus Nephritis Mice Models

Systemic lupus erythematosus is a complex autoimmune disorder mostly mediated by B-cells in which costimulatory signals are involved. This immune dysregulation can cause tissue damage and inflammation of the kidney, resulting in lupus nephritis and chronic renal failure. Given the previous experience reported with CTLA4-Ig as well as recent understanding of the PD-1 pathway in this setting, our group was encouraged to evaluate, in the NZBWF1 model, a human fusion recombinant protein (Hybri) with two domains: CTLA4, blocking the CD28—CD80 costimulatory pathway, and PD-L2, exacerbating the PD-1–PD-L2 coinhibitory pathway. After achieving good results in this model, we decided to validate the therapeutic effect of Hybri in the more severe MRL/lpr model of lupus nephritis. The intraperitoneal administration of Hybri prevented the progression of proteinuria and anti-dsDNA antibodies to levels like those of cyclophosphamide and reduced the histological score, infiltration of B-cells, T-cells, and macrophages and immune deposition in both lupus-prone models. Additionally, Hybri treatment produced changes in both inflammatory-related circulating cytokines and kidney gene expression. To summarize, both in vivo studies revealed that the Hybri effect on costimulatory-coinhibitory pathways may effectively mitigate lupus nephritis, with potential for use as a maintenance therapy.

Lymphatics in Cardiovascular Physiology

The lymphatic vessels play an essential role in maintaining immune and fluid homeostasis and in the transport of dietary lipids. The discovery of lymphatic endothelial cell-specific markers facilitated the visualization and mechanistic analysis of lymphatic vessels over the past two decades. As a result, lymphatic vessels have emerged as a crucial player in the pathogenesis of several cardiovascular diseases, as demonstrated by worsened disease progression caused by perturbations to lymphatic function. In this review, we discuss the major findings on the role of lymphatic vessels in cardiovascular diseases such as hypertension, obesity, atherosclerosis, myocardial infarction, and heart failure.

Retrospective evaluation of systemic hypertension in dogs with nonassociative (primary) immune-mediated hemolytic anemia (December 2016 to April 2019): 26 cases

OBJECTIVE

To report the prevalence of arterial hypertension in a population of dogs with nonassociative immune-mediated hemolytic anemia (IMHA) on presentation and during hospitalization. To determine the relationships of systolic blood pressure (SBP) with mortality and a prognostic indicator, the canine hemolytic anemia objective score.

DESIGN

Retrospective observational study (December 2016 to April 2019).

SETTING

University teaching hospital.

ANIMALS

Twenty-six clinical dogs presenting to the ICU with nonassociative (primary) IMHA and a control group of 23 clinical dogs with idiopathic epilepsy hospitalized in the ICU for seizure treatment or monitoring.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Hypertension was defined as SBP ≥ 160 mm Hg and severe hypertension as SBP ≥ 180 mm Hg. Mean SBP was significantly increased in IMHA dogs (161 mm Hg, SD = 21) compared to ICU control dogs (138 mm Hg, SD = 14; P < 0.005). Hypertension was present in 13 of 26 (50.0%) dogs across the period of hospitalization and was severe in three of 26 (11.5%). During at least 1 day of hospitalization, 18 of 26 (69.2%) dogs were hypertensive and eight of 26 (34.6%) were severely hypertensive. Hypertension was not associated with short-term mortality or canine hemolytic anemia objective score.

CONCLUSIONS

In this retrospective study, hypertension was more prevalent in dogs with nonassociative IMHA than a control population of ICU-hospitalized dogs. An association between autoimmune conditions and hypertension has been previously reported in people but not within a canine population. Hypertension in dogs may have an inflammatory or autoimmune etiology. SBP should be monitored closely in canine IMHA, in case antihypertensive treatment is required.

Trimethylamine N-Oxide Promotes Autoimmunity and a Loss of Vascular Function in Toll-like Receptor 7-Driven Lupus Mice

Plasma levels of trimethylamine N-oxide (TMAO) are elevated in lupus patients. We analyzed the implication of TMAO in autoimmunity and vascular dysfunction of the murine model of systemic lupus erythematosus (SLE) induced by the activation of the Toll-like receptor (TLR)7 with imiquimod (IMQ). Female BALB/c mice were randomly divided into four groups: untreated control mice, control mice treated with the trimethylamine lyase inhibitor 3,3-dimethyl-1-butanol (DMB), IMQ mice, and IMQ mice treated with DMB. The DMB-treated groups were administered the substance in their drinking water for 8 weeks. Treatment with DMB reduced plasma levels of TMAO in mice with IMQ-induced lupus. DMB prevents the development of hypertension, reduces disease progression (plasma levels of anti-dsDNA autoantibodies, splenomegaly, and proteinuria), reduces polarization of T lymphocytes towards Th17/Th1 in secondary lymph organs, and improves endothelial function in mice with IMQ-induced lupus. The deleterious vascular effects caused by TMAO appear to be associated with an increase in vascular oxidative stress generated by increased NADPH oxidase activity, derived in part from the vascular infiltration of Th17/Th1 lymphocytes, and reduced nrf2-driven antioxidant defense. In conclusion, our findings identified the bacterial-derived TMAO as a regulator of immune system, allowing for the development of autoimmunity and endothelial dysfunction in SLE mice.

Gut Microbiota Has a Crucial Role in the Development of Hypertension and Vascular Dysfunction in Toll-like Receptor 7-Driven Lupus Autoimmunity

Our group has investigated the involvement of gut microbiota in hypertension in a murine model of systemic lupus erythematosus induced by Toll-like receptor (TLR)-7 activation. Female BALB/c mice were randomly assigned to four experimental groups: an untreated control (CTR), a group treated with the TLR7 agonist imiquimod (IMQ), IMQ-treated with vancomycin, and IMQ-treated with a cocktail of broad-spectrum antibiotics. We carried out faecal microbiota transplant (FMT) from donor CTR or IMQ mice to recipient IMQ or CTR animals, respectively. Vancomycin inhibited the increase in blood pressure; improved kidney injury, endothelial function, and oxidative stress; and reduced T helper (Th)17 infiltration in aortas from IMQ-treated mice. The rise in blood pressure and vascular complications present in IMQ mice were also observed in the CTR mice recipients of IMQ microbiota. Reduced relative populations of Sutterella and Anaerovibrio were associated with high blood pressure in our animals, which were increased after stool transplantation of healthy microbiota to IMQ mice. The reduced endothelium-dependent vasodilator responses to acetylcholine induced by IMQ microbiota were normalized after interleukin-17 neutralization. In conclusion, gut microbiota plays a role in the TLR7-driven increase in Th17 cell, endothelial dysfunction, vascular inflammation, and hypertension. The vascular changes induced by IMQ microbiota were initiated by Th17 infiltrating the vasculature.

Cardiovascular disease prevention in individuals with underlying chronic inflammatory disease

PURPOSE OF REVIEW

Patients with chronic inflammatory disease have an increased risk of cardiovascular disease. This article reviews the current evidence of cardiovascular prevention in three common systemic inflammatory disorders (SIDs): psoriasis, rheumatoid arthritis, and systemic lupus erythematosus.

RECENT FINDINGS

General population cardiovascular risk assessment tools currently underestimate cardiovascular risk and disease-specific risk assessment tools are an area of active investigation. A disease-specific cardiovascular risk estimator has not been shown to more accurately predict risk compared with the current guidelines. Rheumatoid arthritis-specific risk estimators have been shown to better predict cardiovascular risk in some cohorts and not others. Systemic lupus erythematosus-specific scores have also been proposed and require further validation, whereas psoriasis is an open area of active investigation. The current role of universal prevention treatment with statin therapy in patients with SID remains unclear. Aggressive risk factor modification and control of disease activity are important interventions to reduce cardiovascular risk.

SUMMARY

A comprehensive approach that includes cardiovascular risk factor modification, control of systemic inflammation, and increased patient and physician awareness is needed in cardiovascular prevention of chronic inflammation. Clinical trials are currently underway to test whether disease-specific anti-inflammatory therapies will reduce cardiovascular risk.

Systematic review and meta-analysis of cardiovascular risk in rheumatological disease: Symptomatic and non-symptomatic events in rheumatoid arthritis and systemic lupus erythematosus

Although each autoimmune disease is associated with specific tissue or organ damage, rheumatic diseases share a pro-inflammatory pattern that might increase cardiovascular risk. Retrospective and prospective studies on patients affected by systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) highlighted the concept of "accelerated atherosclerosis". Therefore, the purpose of this systematic review and meta-analysis is the assessment of symptomatic or asymptomatic cardiovascular events among patients with rheumatic diseases as RA and SLE. The literature research obtained all manuscripts published in the English language between 2015 and 2019 for a total of 2355 manuscripts. After selection through inclusion and exclusion criteria, four articles examined cardiovascular risk in RA patients, 8 in SLE patients, and 2 in RA and SLE patients. Patients with SLE had a RR of 1.98 (95% CI: 1.18-3.31) of symptomatic cardiovascular events compared to the unexposed cohort. The meta-regression analysis showed that younger patient (age per year increase β = -0.12 95%CI: -0.20, -0.4), belonging to studies conducted in continent different from America (β = -0.89; -95% CI: 1.67, -0.10), after 2000 (β = 0.87; 95% CI: 0.09, 1.65) and with a higher quality score 0.80 (95% CI: 0.31, 1.29) had a higher risk of cardiovascular events. In patients with RA, the RR of cardiovascular events was 1.55 (95% CI: 1.18-2.02). These data are helpful to implement cardiovascular preventive strategies among people suffering from rheumatologic diseases to decrease the incidence of cardiovascular events. However, these implementation needs to build a higher network between rheumatologists and primary care healthcare workers to furnish the same information to patients and monitor their preventive practice compliance.

Gut microbiota contributes to the development of hypertension in a genetic mouse model of systemic lupus erythematosus

BACKGROUND AND PURPOSE

Hypertension is an important cardiovascular risk factor that is prevalent in the systemic lupus erythematosus patient population. Here, we have investigated whether intestinal microbiota is involved in hypertension in a genetic mouse model of systemic lupus erythematosus.

EXPERIMENTAL APPROACH

Twenty-six-week-old female NZW/LacJ (control) and NZBWF1 (F1 hybrid of New Zealand Black and New Zealand White strains; systemic lupus erythematosus) mice were treated for 6 weeks with a broad-spectrum antibiotic mixture or with vancomycin. Faecal microbiota transplantation was performed from donor systemic lupus erythematosus group to recipient to germ-depleted or germ-free mice.

KEY RESULTS

Antibiotic treatment inhibited the development of hypertension and renal injury, improved endothelial dysfunction and vascular oxidative stress, and decreased aortic Th17 infiltration in NZBWF1 mice. High BP and vascular complications found in systemic lupus erythematosus mice, but not autoimmunity, kidney inflammation and endotoxemia, were reproduced by the transfer of gut microbiota from systemic lupus erythematosus donors to germ-free or germ-depleted mice. Increased proportions of Bacteroides were linked with high BP in these mice. The reduced endothelium-dependent vasodilator responses to acetylcholine and the high BP induced by microbiota from hypertensive systemic lupus erythematosus mice were inhibited after IL-17 neutralization.

CONCLUSION AND IMPLICATIONS

Changes in T-cell populations, endothelial function, vascular inflammation and hypertension driven by a genetic systemic lupus erythematosus background can be modified by antibiotic-induced changes in gut microbiota. The vascular changes induced by hypertensive systemic lupus erythematosus microbiota were mediated by Th17 infiltration in the vasculature.

Toll-like receptor 7-driven lupus autoimmunity induces hypertension and vascular alterations in mice

OBJECTIVE

To investigate whether toll-like receptor 7 (TLR7) activation induces an increase in blood pressure and vascular damage in wild-type mice treated with the TLR7 agonist imiquimod (IMQ).

METHODS

Female BALB/c mice (7-9 week old) were randomly assigned to two experimental groups: an untreated control group and a group treated topically with IMQ (IMQ-treated) for 4 or 8 weeks. A group of IMQ-treated mice that take a combination of the antioxidants tempol and apocynin, and another treated IL-17-neutralizing antibody were also performed.

RESULTS

TLR7 activation gradually increased blood pressure, associated with elevated plasma levels of anti-dsDNA autoantibodies, splenomegaly, hepatomegaly, and severe expansion of splenic immune cells with an imbalance between proinflammatory T cells and regulatory T cells. TLR7 activation induced a marked vascular remodeling in mesenteric arteries characterized by an increased media--lumen ratio (≈40%), and an impaired endothelium-dependent vasorelaxation in aortas from wild-type mice after 8 weeks of treatment. In addition, an increased ROS production, as a result of the upregulation of NADPH oxidase subunits, and an enhanced vascular inflammation were found in aortas from IMQ-treated mice. These functional and structural vascular alterations induced by IMQ were improved by antioxidant treatment. Anti-IL-17 treatment reduced blood pressure and improved endothelial dysfunction in IMQ-treated mice.

CONCLUSION

Our results demonstrate that TLR7 activation induces the development of hypertension and vascular damage in BALB/c mice, and further underscore the increased vascular inflammation and oxidative stress, mediated in part by IL-17, as key factors contributing to cardiovascular complications in this TLR7-driven lupus autoimmunity model.

Proliferative Glomerulonephritis: Risk Factor for Hypertension in Lupus

Studies report a high prevalence of hypertension in lupus, reaching up to 74%. The incidence of hypertension in SLE patients is increased with the severity of the kidney damage. This work was carried out with the objective of determining the prevalence of hypertension in lupus nephritis and to seek the existence of an association between the presence of a proliferative glomerulonephritis and hypertension. Patients and Methods. This was a case-control study, carried out in the nephrology department of the Aristide Le Dantec University Hospital in Dakar. All records of patients with lupus nephritis over a 10-year period, from January 01, 2007, to December 31, 2016, were included. Results. During the study period, out of 64 lupus nephritis records collected, 28 patients had hypertension, for a hospital prevalence of 43.75%. The mean age of the patients was 30.64 years ± 10.44. There were 24 women and 4 men. The mean systolic blood pressure was 156 mmHg (110–220) and the mean diastolic blood pressure was 100 mmHg (80–130). The mean serum creatinine was 29.48 mg/l ± 24.99. The mean proteinuria was 4.50 g/24 h ± 2.87. Hypertriglyceridemia was observed in one patient. Hypercholesterolemia was present in 3 patients. HDL levels were normal in all patients and elevated LDL levels were noted in all 4 patients. None of our patients had diabetes. Class III was found in 11 cases, class IV in 14 cases, pure class V in 2 cases, and class II in 1 case. Hypertension was associated with the presence of proliferative glomerulonephritis (odds ratio, 7.45; 95% CI, 1.9 to 29.1; p=0.002). Conclusion. Hypertension is common in lupus nephritis. The presence of a proliferative glomerulonephritis is a risk factor for the development of arterial hypertension. Screening and adequate management of hypertension are essential for the prevention of the progression of chronic kidney disease in lupus.

Class switching and high-affinity immunoglobulin G production by B cells is dispensable for the development of hypertension in mice

AIMS

Elevated serum immunoglobulins have been associated with experimental and human hypertension for decades but whether immunoglobulins and B cells play a causal role in hypertension pathology is unclear. In this study, we sought to determine the role of B cells and high-affinity class-switched immunoglobulins on hypertension and hypertensive end-organ damage to determine if they might represent viable therapeutic targets for this disease.

METHODS AND RESULTS

We purified serum immunoglobulin G (IgG) from mice exposed to vehicle or angiotensin (Ang) II to induce hypertension and adoptively transferred these to wild type (WT) recipient mice receiving a subpressor dose of Ang II. We found that transfer of IgG from hypertensive animals does not affect blood pressure, endothelial function, renal inflammation, albuminuria, or T cell-derived cytokine production compared with transfer of IgG from vehicle infused animals. As an alternative approach to investigate the role of high-affinity, class-switched immunoglobulins, we studied mice with genetic deletion of activation-induced deaminase (Aicda-/-). These mice have elevated levels of IgM but virtual absence of class-switched immunoglobulins such as IgG subclasses and IgA. Neither male nor female Aicda-/- mice were protected from Ang II-induced hypertension and renal/vascular damage. To determine if IgM or non-immunoglobulin-dependent innate functions of B cells play a role in hypertension, we studied mice with severe global B-cell deficiency due to deletion of the membrane exon of the IgM heavy chain (µMT-/-). µMT-/- mice were also not protected from hypertension or end-organ damage induced by Ang II infusion or deoxycorticosterone acetate-salt treatment.

CONCLUSIONS

These results suggest that B cells and serum immunoglobulins do not play a causal role in hypertension pathology.

Innate Immune Mechanisms of Arterial Hypertension and Autoimmune Disease

The immune system is indispensable in the development of vascular dysfunction and hypertension. The interplay between immune cells and the vasculature, kidneys, heart, and blood pressure regulating nuclei in the central nervous system results in a complex and closely interwoven relationship of the immune system with arterial hypertension. A better understanding of this interplay is necessary for optimized and individualized antihypertensive therapy. Our review article focuses on innate cells in hypertension and to what extent they impact on development and preservation of elevated blood pressure. Moreover, we address the association of hypertension with chronic autoimmune diseases. The latter are ideally suited to learn about immune-mediated mechanisms in cardiovascular disease leading to high blood pressure.

Contribution of Th17 cells to tissue injury in hypertension

PURPOSE OF REVIEW

Hypertension has been demonstrated to be a chief contributor to morbidity and mortality throughout the world. Although the cause of hypertension is multifactorial, emerging evidence, obtained in experimental studies, as well as observational studies in humans, points to the role of inflammation and immunity. Many aspects of immune function have now been implicated in hypertension and end-organ injury; this review will focus upon the recently-described role of Th17 cells in this pathophysiological response.

RECENT FINDINGS

Studies in animal models and human genetic studies point to a role in the adaptive immune system as playing a contributory role in hypertension and renal tissue damage. Th17 cells, which produce the cytokine IL17, are strongly pro-inflammatory cells, which may contribute to tissue damage if expressed in chronic disease conditions. The activity of these cells may be enhanced by physiological factors associated with hypertension such as dietary salt or Ang II. This activity may culminate in the increased sodium retaining activity and exacerbation of inflammation and renal fibrosis via multiple cellular mechanisms.

SUMMARY

Th17 cells are a distinct component of the adaptive immune system that may strongly enhance pathways leading to increased sodium reabsorption, elevated vascular tone and end-organ damage. Moreover, this pathway may lend itself towards specific targeting for treatment of kidney disease and hypertension.

Association of systemic lupus erythematosus with peripheral arterial disease: a meta-analysis of literature studies

OBJECTIVE

SLE patients have an increased cardiovascular morbidity and mortality. Contrasting data are available about the association between peripheral arterial disease (PAD) and SLE. We aimed to perform a meta-analysis of studies evaluating the association between SLE and PAD.

METHODS

Studies were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases according to preferred reporting items for systematic reviews and meta-analyses guidelines.

RESULTS

Eight studies reporting on 263 258 SLE patients and 768 487 controls showed that the prevalence of PAD was 15.8% (95% CI: 10.5%, 23.2%) in SLE patients and 3.9% (95% CI: 1.8%, 7.9%) in controls with a corresponding odds ratio of 4.1 (95% CI: 1.5, 11.6; P <0.001). In addition, five studies reporting on ankle-brachial index showed significantly lower values in 280 SLE patients as compared with 201 controls (mean difference: -0.018; 95% CI: -0.034, -0.001; P =0.033). Meta-regression models showed that age, hypertension and diabetes were inversely associated with the difference in the prevalence of PAD between SLE patients and non-SLE controls, whereas no effect for all the other clinical and demographic variables on the evaluated outcome was found.

CONCLUSION

SLE patients exhibit an increased prevalence of PAD and lower ankle-brachial index values as compared with non-SLE controls. This should be considered when planning prevention, interventional and rehabilitation strategies for these chronic patients with functional disability and poor long-term outcomes.

Management of cardiovascular disease in patients with systemic lupus erythematosus

INTRODUCTION

SLE is increasingly recognized as an important risk factor for cardiovascular disease. Premature CAD and several other cardiac manifestations are resulting in significant morbidity and premature death among young and older adults. There is a considerable unmet need for developing specific guidelines toward the primary and secondary prevention of cardiovascular disease in SLE patients.

AREAS COVERED

The authors describe the prevalence of various cardiovascular manifestations, associated with traditional and lupus-specific risk factors. They summarize the evidence behind various nonpharmacological and pharmacological options such as cardiac medications, antimalarials, anti-inflammatory, and immunosuppressant medications.

EXPERT OPINION

There is considerable literature claiming that the traditional Framingham score used to calculate the risk in the general population would not clearly predict the 10-year risk among SLE patients as they do not include lupus-specific risk factors such as accelerated inflammation, immunometabolic changes, thrombosis, vasospasm, vasculitis, and endothelial dysfunction into account. Identifying potential risk factors among SLE patients and treating hyperlipidemia regardless of their risk scores may be the first step in reducing mortality. Blocking lupus-specific inflammatory pathways by targeting validated biomarkers of pathogenesis has great future potential and more studies are needed on their cardiovascular benefits.

The impact of obesity on disease activity, damage accrual, inflammation markers and cardiovascular risk factors in systemic lupus erythematosus

BACKGROUND

We aimed to evaluate the relationships between obesity metrics including Body Mass Index (BMI), waist to height ratio (WtHR) and fat mass percentage, and disease activity, damage accrual, inflammation markers and traditional cardiovascular risk factors in SLE patients.

METHODS

A cross-sectional study was conducted on a sample of 275 patients (90.5% females; mean age 46.37±13.85 years). Disease activity was assessed with the SLE disease activity index (SLEDAI-2K), and disease-related organ damage was assessed using the SLICC/ACR damage index (SDI). Biochemical variables of lipids profile, high-sensitivity C-reactive protein (hs-CRP), homocysteine (Hcy), anti-dsDNA titers and complement components C3 and C4 serum levels were measured. Blood pressure and ankle-brachial index (ABI) were also calculated.

RESULTS

Significant differences were observed between normal-weight, overweight and obese patients in SLEDAI (2.60±2.48 vs. 2.71±2.65 vs. 3.84±3.02; P=0.004), SDI (0.76±1.10 vs. 1.09±1.24 vs. 1.57±1.54; P=0.002), hsCRP (2.15±2.93 vs. 3.24±3.63 vs. 5.30±5.63 mg/dL; P<0.001), complement C3 level (99.92±24.45 vs. 111.38±27.41 vs. 123.16±28.96 mg/dL; P<0.001), triglycerides serum levels (85.99±41.68 vs. 102.35±50.88 vs. 129.12±61.59 mg/dL; P<0.001) and systolic blood pressure (112.28±16.35 vs. 124.25±17.94 vs. 132.78±16.71 mmHg; P=0.001) after adjusting for age and sex.

CONCLUSIONS

Patients with SLE who are obese have worse disease activity and damage accrual, higher levels of inflammation markers hs-CRP and C3 complement, increased triglycerides serum levels and systolic blood pressure levels in comparison with overweight or normal weight SLE patients, supporting that optimizing weight in SLE patients should be a potential target to improve SLE outcomes.

A review of non-immune mediated kidney disease in systemic lupus erythematosus: A hypothetical model of putative risk factors

About half of patients with systemic lupus erythematosus (SLE) are diagnosed with lupus nephritis (LN). Patients with SLE are also at increased risk for diabetes, hypertension and obesity, which together account for >70% of end-stage renal disease in the general population. The frequencies of non-LN related causes of kidney disease, and their contribution to kidney disease development and progression among patients with SLE have been inadequately studied. We hypothesize that a substantial, and increasing proportion of kidney pathology in patients with SLE might not directly relate to LN but instead might be explained by non-immune mediated factors such as diabetes, hypertension, and obesity. The goal of the manuscript is to draw attention to hypertension, diabetes and obesity as potential alternative causes of kidney damage in patients with SLE. Further, we suggest that misclassification of kidney disease etiology in patients with SLE might have important ramifications for clinical trial recruitment, epidemiologic investigation, and clinical care. Future studies aiming to elucidate and distinguish discrete causes of kidney disease - both clinically and histologically - among patients with SLE are desperately needed as improved understanding of disease mechanisms is paramount to advancing therapeutic discovery. Collaboration among rheumatologists, pathologists, nephrologists, and endocrinologists, and the availability of dedicated research funding, will be critical to the success of such efforts.

Protective Effects of Probiotic Consumption in Cardiovascular Disease in Systemic Lupus Erythematosus

The prevalence of renal and cardiovascular disease (CVD) in patients with systemic lupus erythematosus (SLE) is higher than in general populations. Recently, a causal role of gut microbiota on the development of immune responses in SLE has been described. Probiotic consumption changes the composition of gut microbiota, preventing SLE progression. The aim of this review is to explore the role of the gut microbiota in the development of renal and cardiovascular disease in SLE and how probiotics could be a therapeutic option. Despite strong evidence on the beneficial effects of probiotics in the development of autoimmunity and nephritis in SLE, only a few studies described the protective effects of Lactobacillus in important risk factors for CVD, such as endothelial dysfunction and hypertension in mice. The preventive effects of probiotics in renal and CVD in humans have not been established yet.

Cyclophosphamide treatment for hypertension and renal injury in an experimental model of systemic lupus erythematosus

Cardiovascular disease is the major cause of mortality among patients with the autoimmune disorder systemic lupus erythematosus (SLE). Our laboratory previously reported that immunosuppression with mycophenolate mofetil, a common therapy in patients with SLE, attenuates the development of hypertension in an experimental model of SLE. Cyclophosphamide (CYC) is another common therapy for patients with SLE that has contributed to improved disease management; however, its impact on the development of hypertension associated with SLE is not clear. We tested whether treatment with CYC (25 mg/kg, once/week, IP injection) for 4 weeks would attenuate hypertension in an established female mouse model of SLE with hypertension (30-week-old NZBWF1 females). Plasma anti-dsDNA IgG levels, pathogenic for the disease, were lower in CYC-treated SLE mice compared to vehicle-treated SLE mice, suggesting efficacy of the therapy to suppress aberrant immune system function. Mean arterial pressure (MAP) was assessed by carotid artery catheters in conscious mice. Treatment did not attenuate the development of hypertension when compared to vehicle-treated SLE mice; however, urinary albumin excretion was lower in CYC-treated animals. Corresponding with the reduction in autoantibodies, data suggest that CYC treatment lowered circulating CD45R+ B cells. Paradoxically, circulating CD11b+ Ly6G+ neutrophils were increased in CYC-treated SLE mice compared to vehicle treated. Estrus cycling data also suggest that CYC treatment had an impact on ovarian function that may be consistent with reduced circulating estrogen levels. Taken together, these data suggest that CYC treatment attenuates autoantibody production and renal disease during SLE, but that the potential to affect MAP may be blunted by the increase in circulating neutrophils and CYC's impact on ovarian function.

Incidence and survival impact of pulmonary arterial hypertension among patients with systemic lupus erythematosus: a nationwide cohort study

Background

No population-based study has investigated the cumulative incidence of pulmonary arterial hypertension (PAH) in patients with newly diagnosed systemic lupus erythematosus (SLE) or the survival impact of PAH in this population.

Method

We used a nationwide database in Taiwan and enrolled incident SLE patients between January 1, 2000, and December 31, 2013. The cumulative incidence of PAH in the SLE patients and the survival of these patients were estimated by the Kaplan-Meier method. Potential predictors of the development of PAH were determined using a Cox proportional hazards regression model.

Results

Of 15,783 SLE patients, 336 (2.13%) developed PAH. The average interval from SLE diagnosis to PAH diagnosis was 3.66 years (standard deviation [SD] 3.36, range 0.1 to 13.0 years). Seventy percent of the patients developed PAH within 5 years after SLE onset. The 3- and 5-year cumulative incidence of PAH were 1.2% and 1.8%, respectively. Systemic hypertension was an independent predictor of PAH occurrence among the SLE patients (adjusted hazard ratio 2.27, 95% confidence interval 1.59–2.97). The 1-, 3-, and 5-year survival rates of SLE patients following the diagnosis of PAH were 87.7%, 76.8%, and 70.1%, respectively.

Conclusions

PAH is a rare complication of SLE and the majority of PAH cases occur within the first 5 years following SLE diagnosis. Systemic hypertension may be a risk factor for PAH development in the SLE population. The overall 5-year survival rate after PAH diagnosis was 70.1%.

Expansion of regulatory T cells using low-dose interleukin-2 attenuates hypertension in an experimental model of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disorder that is characterized by prevalent hypertension, renal injury, and cardiovascular disease. Numerous studies have reported a low prevalence and/or impaired function of regulatory T (T_REG) cells in both patients with SLE and murine models of the disease. Evidence suggests that T_REG cell dysfunction in SLE results from a deficiency in IL-2. Recent studies have reported that low-dose IL-2 therapy expands T_REG cells in mouse models of SLE, but whether expanding T_REG cells protects against hypertension and renal injury during SLE is unclear. To examine this question, female SLE (NZBWF1) and control (NZW) mice were injected with vehicle or recombinant mouse IL-2 three times in 24 h followed by single maintenance doses every 5 days for 4 wk. Treatment with IL-2 effectively expanded T_REG cell populations in the peripheral blood, spleen, and kidneys. Circulating levels of anti-dsDNA IgG autoantibodies, a marker of SLE disease activity, were higher in SLE mice compared with control mice but were unaffected by IL-2 treatment. As previously reported by our laboratory, mean arterial pressure, measured in conscious mice by a carotid catheter, was higher in SLE mice than in control mice. Mean arterial pressure was significantly lower in IL-2-treated SLE mice compared with vehicle-treated SLE mice, suggesting that expanding T_REG cells using low-dose IL-2 attenuates the development of hypertension. While the mechanism for the protection against hypertension is unclear, it does not appear to be related to the delay of SLE disease progression.

Blood pressure control over time in childhood-onset systemic lupus erythematous

Introduction Hypertension (HTN) is prevalent in patients with systemic lupus erythematosus (SLE) and causes early cardiovascular aging and progression of renal and cardiac disease. The aim of this longitudinal retrospective study was to evaluate the prevalence of HTN, the follow-up blood pressure trends, and risk factors for HTN in a population-based cohort with childhood-onset SLE (cSLE). Methods Demographic and clinical data of consecutive visits from the baseline to the last visit were extracted from electronic medical records of patients with cSLE. Results A total of 110 patients with cSLE were identified with a median follow-up duration of 29.5 months; 19% had lupus nephritis (LN) at diagnosis. Further, 29% and 23% had HTN and preHTN at the baseline visit. Compared to those without HTN, patients with HTN had higher disease activity, obesity, more frequent LN, and lower eGFR. In multivariate analysis, the presence of LN, obesity, and high extra-renal disease activity were independent predictors of HTN at baseline. Conclusions While HTN is a known feature of LN, HTN is common and persistent in cSLE without LN, with about one-third of patients having uncontrolled elevated blood pressure almost three years after the onset of lupus. In addition to LN, obesity and high overall disease activity were independent predictors of HTN.

Hypertension as a cardiovascular risk factor in autoimmune rheumatic diseases

Evidence for the increased risk of cardiovascular morbidity and mortality in patients with chronic inflammatory and systemic autoimmune diseases has accumulated during the past 15 years. In these patients, an interplay between several mechanisms, including premature acceleration of subclinical atherosclerotic damage, inflammation, and dysregulation of the immune system, is involved in the induction and progression of atherosclerosis. Moreover, traditional cardiovascular risk factors are also likely to contribute, at least in part, to the excess cardiovascular risk. Among traditional cardiovascular risk factors, hypertension is an important predictor of cardiovascular events in the general population and in patients with chronic inflammatory and autoimmune diseases. Evidence supports the idea that the pathogenic mechanisms underlying the increased blood pressure in these diseases are multifactorial and not only related to the mechanical injury of the arterial wall. In particular, chronic inflammation and immune-mediated mechanisms have been demonstrated to affect blood-pressure control in patients with systemic autoimmune disease. In this Review, we discuss the available evidence on the relationship between hypertension and autoimmune diseases, and describe the multiple factors that might affect blood-pressure control in patients with chronic inflammatory and systemic autoimmune diseases. We also discuss the effect of hypertension and antirheumatic therapies on cardiovascular outcome.

Role of Inflammatory Diseases in Hypertension

Chronic inflammatory diseases (CID) are characterized by an increased risk of cardiovascular (CV) morbidity and mortality. Several mechanisms, including early acceleration of subclinical atherosclerotic damage, inflammatory markers and immune system deregulation factors, have been demonstrated to strictly interplay for development and progression of atherosclerosis. Moreover, traditional CV risk factors are likely to explain at least some of the excess of CV risk in these patients. Among traditional CV risk factors, compelling evidence suggests a higher incidence and prevalence of hypertension in patients with CID in comparison to the general population. Moreover, hypertension represents an important predictor of CV events in these patients. Pathogenic mechanisms underlying the rise of blood pressure in CID are multifactorial and still poorly investigated. Indeed, multiple disease-related factors may affect blood pressure control in these patients and hypertension may affect disease prognosis and increase CV risk. Better knowledge of the complex interplay between hypertension and CID will be important to elucidate pathogenic mechanisms and to improve CV outcome in these patients. Aim of this review is to highlight available evidence on the relationship between hypertension and CID and to elucidate the multiple factors that may affect blood pressure control in these disorders.

Direct measurement of B-cell receptor repertoire's composition and variation in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that is known to be associated with polyclonal B-cell hyper-reactivity. B-cell receptor (BCR) has a central role in B-cell development, activation, survival and apoptosis, and thus is a critical component of the regulation of both protective and autoreactive B cells. In this study, we applied multiplex PCR and Illumina high-throughput sequencing to study the composition and variation of the BCRs in peripheral blood mononuclear cells from SLE patients and healthy donors (NC). We found that SLE group displayed significantly shorter CDR3 average length (14.86±0.76aa vs 15.70±0.43aa), more arginine percentage of CDR3 amino acids (7.57±0.20% vs 7.32±0.19%) and poorer immunological diversity than the healthy ones. CDR3 sequence YGMDV present in all SLE samples may provide more information in generating more effective B-cell targeted diagnosis/therapies strategies.