Group A Streptococcus Vaccine Targeting the Erythrogenic Toxins SpeA and SpeB Is Safe and Immunogenic in Rabbits and Does Not Induce Antibodies Associated with Autoimmunity

Group A streptococcus (GAS) is a global pathogen associated with significant morbidity and mortality for which there is currently no licensed vaccine. Vaccine development has been slow, mostly due to safety concerns regarding streptococcal antigens associated with autoimmunity and related complications. For a GAS vaccine to be safe, it must be ensured that the antigens used in the vaccine do not elicit an antibody response that can cross-react with host tissues. In this study, we evaluated the safety of our GAS vaccine candidate called VaxiStrep in New Zealand White rabbits. VaxiStrep is a recombinant fusion protein comprised of streptococcal pyrogenic exotoxin A (SpeA) and exotoxin B (SpeB), also known as erythrogenic toxins, adsorbed to an aluminum adjuvant. The vaccine elicited a robust immune response against the two toxins in the rabbits without any adverse events or toxicity. No signs of autoimmune pathology were detected in the rabbits' brains, hearts, and kidneys via immunohistochemistry, and serum antibodies did not cross-react with cardiac or neuronal tissue proteins associated with rheumatic heart disease or Sydenham chorea (SC). This study further confirms that VaxiStrep does not elicit autoantibodies and is safe to be tested in a first-in-human trial.

Decade-long mitral valve surgery trends and rheumatic heart disease: a review of mitral valve surgery in a large Chinese cardiovascular center

BACKGROUND

Despite being one of the few chronic secondary heart diseases that can be prevented, current epidemiological data on rheumatic heart disease (RHD) in China are unavailable. This study examined mitral valve (MV) surgery trends in a large Chinese cardiovascular center over the last 10 years and provided insight into the distribution of RHDs and their changes.

METHODS

Medical records of patients who underwent cardiac surgery, MV surgery, and MV surgery for rheumatic MV (rMV) disease at Beijing Anzhen Hospital between January 2010 and December 2019 were retrospectively reviewed. Patients' demographic and clinical characteristics were statistically analyzed among age groups.

RESULTS

Overall, 7,736 patients underwent rMV surgery and 87.5% were aged 40-70 years. The proportion of patients aged >60 years increased annually (P<0.05), and the proportion of patients in all other age groups decreased. The proportion of patients with rMV diseases among those with cardiac or mitral valve diseases decreased each year, but the absolute number of patients with rMV disease remained stable. Approximately 90% of patients who underwent rMV surgery were from northern China. The incidence of rMV disease among patients with mitral valve disease moderately correlated with the per capita gross regional product (Per-GRP), an indicator of living standards (r=-0.517, P<0.05).

CONCLUSIONS

RHD still exists in northern China and requires adequate resources for its management. The number of older patients with rMV disease presents a challenge for mitral valve surgery.

Differences in socio-demographic and risk factor profile, clinical presentation, and outcomes between patients with and without RHD heart failure in Sub-Saharan Africa: results from the THESUS-HF registry

Background

Rheumatic heart disease (RHD) was found in the THESUS-HF registry to be the third most common cause of acute heart failure (AHF) in Sub-Saharan Africa.

Methods

One thousand six patients with AHF from 9 Sub-Saharan African countries were recruited in THESUS-HF, of which 143 (14.3%) had RHD-AHF. Clinical characteristics and outcomes in patients with RHD-AHF and non-RHD-AHF were compared. Kaplan-Meier plots for time to all-cause death and/or HF readmission according to the presence of RHD-AHF and non-RHD-AHF were performed and survival distributions compared using the log-rank test. Cox regression was used to determine the hazard ratio of death to day 180 and death or readmission to day 60 after adjusting for confounders.

Results

Patients with RHD-AHF were younger, more often females, had higher rates of atrial fibrillation, had less hypertension, hyperlipidemia and diabetes, had lower BP, and higher pulse rate and better kidney function and echocardiographic higher ejection fraction larger left atria and more diastolic dysfunction. Patients with RHD-AHF had a numerically longer mean stay in the hospital (10.5 vs. 8.8 days) and significantly higher initial hospitalization mortality (9.1% vs. 3.4%).

Conclusions

In conclusion, patients with HF related to RHD were younger, have higher rate of atrial fibrillation and have a worse short-term outcome compared to HF related to other etiologies in Sub-Saharan Africa.

Rheumatic heart disease: current status of diagnosis and therapy

Rheumatic heart disease (RHD) is the only preventable cardiovascular disease which causes significant morbidity and mortality particularly in low- and middle-income countries. Early clinical diagnosis is key, the updated Jones criteria increases the likelihood of diagnosis in endemic settings, including the echo diagnosis of sub-clinical carditis, polyarthralgia and monoarthritis as well as amended thresholds of minor criteria. The mainstay of rheumatic heart valve disease (RHVD) is a thorough clinical and echocardiographic investigation while severe disease is managed with medical, interventional and surgical treatment. In this report we detail some of the more recent epidemiological findings and focus on the diagnostic and interventional elements of the specific valve lesions. Finally, we discuss some of the recent efforts to improve medical and surgical management for this disease. As we are already more than a year from the historic 2018 World Heart Organization Resolution against Rheumatic Fever and Rheumatic Heart Disease, we advocate strongly for renewed efforts to prioritize this disease across the endemic regions of the world.

Infective endocarditis in South Africa

Infective endocarditis (IE) is defined by infection of either a native or prosthetic heart valve, endocardial surface or any cardiac prosthetic device. It is a disease of both the developed and developing world, although IE has evolved in the developed world to a disease markedly different to the disease encountered in the developing world. IE in developed nations is mainly a disease of older patients with degenerative heart valve disease or cardiac prosthetic material, with virulent Staphylococci the most common causative organism. Data regarding the epidemiology of IE in South Africa, a developing country, is limited. The available data suggest it is still a disease of younger patients with rheumatic heart disease (RHD), associated with penicillin-sensitive Streptococcal infection. Although novel diagnostic techniques and improved therapeutic options has emerged, the 1-year mortality rate has remained high in both the developed and developing world at around 30%.

A predictor for mitral valve repair in patient with rheumatic heart disease: the bending angle of anterior mitral leaflet

Background

Mobility and flexibility of anterior mitral leaflet (AML) are considered to be the important factor for mitral valve (MV) repair in rheumatic population, we try to use the bending angle of AML to quantify its' mobility and flexibility and investigate whether it can predict the success of rheumatic MV repair or not.

Methods

Total 54 patients underwent rheumatic MV surgeries with mild lesions of subvalvular apparatus from August, 2017 to November, 2017 at the author institution, we divided the patients into MV repair and MV replacement groups which included directly MV replacement and repair attempt but failed repairing transfer to replacement intraoperatively. Patients' MV structure was carefully evaluated on transthoracic echocardiography (TTE) and scored by the Wilkins score (WS) preoperatively. The bending angle of AML was measured during systole and diastole at different level before surgery.

Results

The differences of patients' demographic characteristics between repair group and replacement group were not statistically significant (P value >0.05) and the differences among B-angle, T-angle, Bs-angle, C-angle of AML between repair group and replacement groups were not statistically significant (P value >0.05). Only BT-angle in repair group was significantly larger than that of replacement group (21.56°±3.84°, 10.29°±6.02°, respectively, P<0.001), therefore the BT-angle was tested as a predictor of reparability by observing the receiver operating characteristic (ROC) curve (ROC area: 0.944, standard error: 0.06, 95% CI: 0.826-1), BT-angle of AML on preoperative transthoracic echo of 15.5° or more predicts feasibility of rheumatic MV repair with 100% sensitivity and 85.7% specificity in patients with mild lesions of subvalvular apparatus. Logistic regression for a single area of calcification (diameter <0.8 cm) at commissure were shown that: β: 0.08, Exp (β): 1.083, P: 0.777>0.05, the minor single calcified area at commissure had no effect on reparability of rheumatic MV disease. The differences of total WS and each component score between repair group and replacement group were not statistically significant (P value >0.05). By observing the ROC curve for total WS (ROC area: 0.508), the WS cannot be a predictor for the rheumatic MV repair.

Conclusions

The bending angle of AML which was considered as quantification of mobility and flexibility of AML can be a predictor for MV repair in patients with rheumatic heart disease (RHD). The small single area of commissural calcification had no effect on reparability of rheumatic MV disease. WS cannot appropriately predict the outcome of rheumatic MV repair.

Young professionals for health development: the Kenyan experience in combating non-communicable diseases

Young individuals (below 35 years) comprise an estimated 60% of the global population. Not only are these individuals currently experiencing chronic, non-communicable diseases (NCDs), either living with or at risk for these conditions, but will also experience the long-term repercussions of the current NCD policy implementations. It is thus imperative that they meaningfully contribute to the global discourse and responses for NCDs at the local level. Here, we profile one example of meaningful engagement: the Young Professionals Chronic Disease Network (YPCDN). The YPCDN is a global online network that provides a platform for young professionals to deliberate new and innovative methods of approaching the NCD challenges facing our societies. We provide a case study of the 2-year experiences of a country chapter (Kenya) of the YPCDN to demonstrate the significance and impact of emerging leaders in addressing the new global health agenda of the 21st century.