Diarrhea with secondary decompensation is the main cause of morbidity and mortality in captive young rhesus macaque (Macaca mulatta) colonies. Approximately 25% of diarrhea cases with secondary decompensation are considered to be idiopathic chronic diarrhea. The purpose of this study was to investigate the suspected but not systematically examined association between rotavirus infection and diarrhea with secondary decompensation among young rhesus macaques at the California National Primate Research Center (CNPRC). Blood and stool samples were collected from 89 randomly selected young animals (age range: 6 months to 1.5 years) and were tested for the presence of rotavirus antibody, and rotavirus antigen, respectively, using enzyme-linked immunosorbent assays (ELISA's). Test and clinical data were analyzed using Fisher's exact tests and multivariate logistic regression model. Our analysis indicates that rotavirus is endemic among young outdoor-housed rhesus macaques at the CNPRC. Although the relationship between detectable rotavirus antigen in stool and symptomatic diarrhea with secondary decompensation was not significant, there was a significant association between rotavirus seropositivity and a history of diarrhea with secondary decompensation within the past 6 months. While our cross-sectional and case-control study suggests an association between rotavirus infection and diarrhea with secondary decompensation among captive rhesus macaques, more extensive longitudinal studies on larger cohorts and with more intensive sample collection are needed to confirm these findings.

Despite numerous therapeutic advances in pulmonary arterial hypertension, patients continue to suffer high morbidity and mortality, particularly considering a median age of 50 years. This article explores whether early, robust reduction of right ventricular afterload would facilitate substantial improvement in right ventricular function and thus whether afterload reduction should be a treatment goal for pulmonary arterial hypertension. The earliest clinical studies of prostanoid treatment in pulmonary arterial hypertension demonstrated an important link between lowering mean pulmonary arterial pressure (or pulmonary vascular resistance) and improved survival. Subsequent studies of oral monotherapy or sequential combination therapy demonstrated smaller reductions in mean pulmonary arterial pressure and pulmonary vascular resistance. More recently, retrospective reports of initial aggressive prostanoid treatment or initial combination oral and parenteral therapy have shown marked afterload reduction along with significant improvements in right ventricular function. Some data suggest that reaching threshold levels for pressure or resistance (components of right ventricular afterload) may be key to interrupting the self-perpetuating injury of pulmonary vascular disease in pulmonary arterial hypertension and could translate into improved long-term clinical outcomes. Based on these clues, the authors postulate that improved clinical outcomes might be achieved by targeting significant afterload reduction with initial oral combination therapy and early parenteral prostanoids.

Rationale: Oral treprostinil improves exercise capacity in patients with pulmonary arterial hypertension (PAH), but the effect on clinical outcomes was unknown.Objectives: To evaluate the effect of oral treprostinil compared with placebo on time to first adjudicated clinical worsening event in participants with PAH who recently began approved oral monotherapy.Methods: In this event-driven, double-blind study, we randomly allocated 690 participants (1:1 ratio) with PAH to receive placebo or oral treprostinil extended-release tablets three times daily. Eligible participants were using approved oral monotherapy for over 30 days before randomization and had a 6-minute-walk distance 150 m or greater. The primary endpoint was the time to first adjudicated clinical worsening event: death; hospitalization due to worsening PAH; initiation of inhaled or parenteral prostacyclin therapy; disease progression; or unsatisfactory long-term clinical response.Measurements and Main Results: Clinical worsening occurred in 26% of the oral treprostinil group compared with 36% of placebo participants (hazard ratio, 0.74; 95% confidence interval, 0.56-0.97; P = 0.028). Key measures of disease status, including functional class, Borg dyspnea score, and N-terminal pro-brain natriuretic peptide, all favored oral treprostinil treatment at Week 24 and beyond. A noninvasive risk stratification analysis demonstrated that oral treprostinil-assigned participants had a substantially higher mortality risk at baseline but achieved a lower risk profile from Study Weeks 12-60. The most common adverse events in the oral treprostinil group were headache, diarrhea, flushing, nausea, and vomiting.Conclusions: In participants with PAH, addition of oral treprostinil to approved oral monotherapy reduced the risk of clinical worsening.Clinical trial registered with www.clinicaltrials.gov (NCT01560624).