Biomarkers of Pulmonary Hypertension Are Altered in Children with Down Syndrome and Pulmonary Hypertension

Association between serum levels of inflammatory mediators and periodontitis severity in people with down syndrome

Evidence suggests that individuals with Down syndrome (DS) have a high prevalence of periodontal disease (PD). Factors such as muscular hypotonia, macroglossia, intellectual deficits, and reduced motor coordination, often combined with inadequate dietary habits, contribute to the development of PD. Additionally, a compromised immune response may explain the altered inflammatory profile that affects the systemic and oral health of this population. This study aimed to analyze the relationship between serum levels of inflammatory cytokines (IFN-γ, IL-10, IL-17, IL-1β, IL-4, and TNF-α) and the severity of periodontitis in individuals with DS. We conducted a case-control study involving individuals with DS (n = 43) and non-syndromic individuals (n = 20). All participants underwent a clinical periodontal examination that included measurements of probing pocket depth (PPD), clinical attachment level (CAL), gingival bleeding index (GBI), and visible plaque index (VPI). Participants were classified into stages of periodontitis: stage 1 and stages 2-4, forming two subgroups within both the case and control groups. Serum levels of IFN-γ, IL-10, IL-17, IL-1β, IL-4, and TNF-α were compared between subgroups and analyzed as continuous variables for independent samples. We compared the four subgroups while considering the stage of periodontitis and the presence of DS. The relationship between DS and the stages 2-4 periodontitis with inflammatory marker levels was analyzed using linear regression models, adjusted for age and sex. The results showed no association between periodontitis severity and serum cytokine levels in any of the subgroups (P > 0.05). However, DS was associated with reduced serum levels of IFN-γ and increased serum levels of IL-10, IL-1β, IL-4, and TNF-α (P < 0.05). These findings suggest that individuals with DS have increased serum levels of inflammatory cytokines compared to non-syndromic individuals, regardless of the severity of periodontitis.

Cellular Communication Network Protein 2 in the Right Ventricle of Pulmonary Arterial Hypertension

Cellular communication network 2 (CCN2) is a secreted matricellular protein associated with pulmonary arterial hypertension (PAH) but has not been studied relative to PAH severity, outcomes, or right ventricle (RV) structure and function in a large human cohort and preclinical animal model. This study assessed the associations between CCN2 and PAH severity, survival, hemodynamic measurements, and cardiovascular dysfunction. Serum CCN2 levels were compared in 2548 adults with PAH and 216 controls. CCN2 levels in PAH patients were compared to functional and hemodynamic measurements, and survival outcomes. RV-pulmonary artery coupling and RV morphology were also assessed in a small subset of patients via pressure-volume loops and cardiac magnetic resonance imaging. In a preclinical PAH model, plasma CCN2 levels were compared between ventricles with PAH progression. CCN2 mRNA levels in both ventricles in the preclinical model were measured to compare with morphologic histologic variables. CCN2 serum levels were significantly higher in PAH compared to controls (p < 0.0001). Higher CCN2 levels were associated with reduced RV contractility (p = 0.003). Higher CCN2 levels were associated with worse 6MWD (p = 0.035), and higher risk of mortality or transplant (p = 0.025). In the preclinical model, prepulmonary CCN2 plasma levels increased with the progression of disease. CCN2 mRNA levels in the RV were associated with decreased RV capillary density (p = 0.015) and increased RV fibrosis (p = 0.045). Though more investigation is needed, it appears that CCN2 plays a role in the development of PAH and potentially in RV maladaptation in PAH.

Pulmonary Hypertension in Children with Down Syndrome: Results from the Pediatric Pulmonary Hypertension Network Registry

OBJECTIVE

To characterize distinct comorbidities, outcomes, and treatment patterns in children with Down syndrome and pulmonary hypertension in a large, multicenter pediatric pulmonary hypertension registry.

STUDY DESIGN

We analyzed data from the Pediatric Pulmonary Hypertension Network (PPHNet) Registry, comparing demographic and clinical characteristics of children with Down syndrome and children without Down syndrome. We examined factors associated with pulmonary hypertension resolution and a composite outcome of pulmonary hypertension severity in the cohort with Down syndrome.

RESULTS

Of 1475 pediatric patients with pulmonary hypertension, 158 (11%) had Down syndrome. The median age at diagnosis of pulmonary hypertension in patients with Down syndrome was 0.49 year (IQR, 0.21-1.77 years), similar to that in patients without Down syndrome. There was no difference in rates of cardiac catheterization and prescribed pulmonary hypertension medications in children with Down syndrome and those without Down syndrome. Comorbidities in Down syndrome included congenital heart disease (95%; repaired in 68%), sleep apnea (56%), prematurity (49%), recurrent respiratory exacerbations (35%), gastroesophageal reflux (38%), and aspiration (31%). Pulmonary hypertension resolved in 43% after 3 years, associated with a diagnosis of pulmonary hypertension at age <6 months (54% vs 29%; P = .002) and a pretricuspid shunt (65% vs 38%; P = .02). Five-year transplantation-free survival was 88% (95% CI, 80%-97%). Tracheostomy (hazard ratio [HR], 3.29; 95% CI, 1.61-6.69) and reflux medication use (HR, 2.08; 95% CI, 1.11-3.90) were independently associated with a composite outcome of severe pulmonary hypertension.

CONCLUSIONS

Despite high rates of cardiac and respiratory comorbidities that influence the severity of pulmonary hypertension, children with Down syndrome-associated pulmonary hypertension generally have a survival rate similar to that of children with non-Down syndrome-associated pulmonary hypertension. Resolution of pulmonary hypertension is common but reduced in children with complicated respiratory comorbidities.

Pulmonary Hypertension in the Population with Down Syndrome

Persons with Down syndrome (DS) have an increased reported incidence of pulmonary hypertension (PH). A majority of those with PH have associations with congenital heart disease (CHD) or persistent pulmonary hypertension of the newborn (PPHN); however, there are likely multifactorial contributions that include respiratory comorbidities. PH appears to be most commonly identified early in life, although respiratory challenges may contribute to a later diagnosis or even a recurrence of previously resolved PH in this population. Currently there are few large-scale, prospective, lifetime cohort studies detailing the impact PH has on the population with DS. This review will attempt to summarize the epidemiology and characteristics of PH in this population. This article will additionally review current known and probable risk factors for developing PH, review pathophysiologic mechanisms of disease in the population with DS, and evaluate current screening and management recommendations while suggesting areas for additional or ongoing clinical, translational, and basic science research.