Adipose-Derived Stem Cells Promote Intussusceptive Lymphangiogenesis by Restricting Dermal Fibrosis in Irradiated Tissue of Mice.

Currently, there is no definitive treatment for lymphatic disorders. Adipose-derived stem cells (ADSCs) have been reported to promote lymphatic regeneration in lymphedema models, but the mechanisms underlying the therapeutic effects remain unclear. Here, we tested the therapeutic effects of ADSC transplantation on lymphedema using a secondary lymphedema mouse model. The model was established in C57BL/6J mice by x-irradiation and surgical removal of the lymphatic system in situ. The number of lymphatic vessels with anti-lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) immunoreactivity increased significantly in mice subjected to transplantation of 7.5 × 105 ADSCs. X-irradiation suppressed lymphatic vessel dilation, which ADSC transplantation could mitigate. Proliferative cell nuclear antigen staining showed increased lymphatic endothelial cell (LEC) and extracellular matrix proliferation. Picrosirius red staining revealed normal collagen fiber orientation in the dermal tissue after ADSC transplantation. These therapeutic effects were not related to vascular endothelial growth factor (VEGF)-C expression. Scanning electron microscopy revealed structures similar to the intraluminal pillar during intussusceptive angiogenesis on the inside of dilated lymphatic vessels. We predicted that intussusceptive lymphangiogenesis occurred in lymphedema. Our findings indicate that ADSC transplantation contributes to lymphedema reduction by promoting LEC proliferation, improving fibrosis and dilation capacity of lymphatic vessels, and increasing the number of lymphatic vessels via intussusceptive lymphangiogenesis.

Reaching every child with rotavirus vaccine: Report from the 10th African rotavirus symposium held in Bamako, Mali.

The Center for Vaccine Development - Mali (CVD - Mali), the World Health Organization's regional office in Africa (WHO/AFRO), and the CVD at the University of Maryland School of Medicine hosted the 10th African Rotavirus Symposium in Bamako, Mali on 1-2 June 2016. The symposium is coordinated by WHO/AFRO, the Regional Rotavirus Reference Laboratories, and the African Rotavirus Network (ARN), with support from the Bill & Melinda Gates Foundation. The event brings together leading rotavirus researchers, scientists, and policy-makers from across Africa and the world. Over 150 participants, from 31 countries, including 27 in Africa, joined forces to address the theme "Reaching Every Child in Africa with Rotavirus Vaccines." This symposium, the first in francophone Africa, occurred at an unprecedented time when 33 African countries had introduced rotavirus vaccines into their national immunization programs. The symposium concluded with a Call to Action to introduce rotavirus vaccines in the 21 remaining African countries, to increase access in countries with existing vaccination programs, and to continue surveillance and research on rotavirus and other diarrheal diseases.

Paediatric Active Enhanced Disease Surveillance inaugural annual report, 2014.

INTRODUCTION: The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is a hospital-based active surveillance system employing prospective case ascertainment of selected uncommon vaccine preventable diseases and potential adverse events following immunisation (AEFI). PAEDS enhances other Australian surveillance systems by providing prospective detailed clinical and laboratory data for the same child. METHODS: Specialist surveillance nurses screen hospital admissions, emergency department records, laboratory and other data, to prospectively identify hospitalised children aged under 15 years in 5 paediatric tertiary referral hospitals in New South Wales, Victoria, South Australia, Western Australia and Queensland. Standardised protocols and case definitions are used across all sites. Conditions under surveillance include vaccine preventable diseases: acute flaccid paralysis, varicella, pandemic and seasonal influenza and pertussis, and potential AEFIs: febrile seizures and intussusception. PAEDS also conducts surveillance for acute childhood encephalitis. RESULTS: Since August 2007, PAEDS has recruited a total of 6,227 hospitalised cases in total, for all conditions. From January to December 2014, there were 1,220 cases recruited across all conditions. Key outcomes include: enhanced acute flaccid paralysis surveillance to reach World Health Organization targets; supporting varicella and influenza vaccination in children; confirmation of a known low risk of febrile seizures following the 1st dose of measles-mumps-rubella vaccine but no increased risk of febrile seizures after measles-mumps-rubella-varicella vaccine, and a slightly increased risk of developing intussusception 1-7 days after rotavirus vaccination in infants aged less than 3 months. Acute childhood encephalitis data facilitated rapid investigation and response to the enterovirus 71 outbreak in 2013-2014. CONCLUSIONS: PAEDS provides unique policy-relevant data. This is the first of planned PAEDS annual reports to Communicable Diseases Intelligence.

Role of innate immunity and altered intestinal motility in LPS- and MnCl2-induced intestinal intussusception in mice.

Intestinal intussusception (ISS) commonly causes intestinal obstruction in children. One mechanism that has been proposed to cause ISS is inflammation-induced alteration of intestinal motility. We investigated whether innate inflammatory factors or altered motility is required for induction of ISS by LPS. We compared rates of ISS among BALB/c and C57BL/6 mice, mice lacking lymphocytes or depleted of phagocytes, or mice with defects in the Toll-like receptor 4 (TLR4) signaling pathway following administration of LPS or the Ca(2+) analog MnCl2. At 6 or 2 h after administration of LPS or MnCl2, respectively, mice underwent image analysis to assess intestinal contraction rate or laparotomy to identify ISS. LPS-induced ISS (LPS-ISS) was observed in BALB/c mice, but not in C57BL/6 mice or any BALB/c mice with disruptions of TLR4 signaling. LPS-induced serum TNF-α, IL-6, and nitric oxide (NO) and intestinal NO levels were similar in BALB/c and C57BL/6 mice. The rate of LPS-ISS was significantly reduced in phagocyte-depleted, but not lymphocyte-deficient, mice. Intestinal contraction rates were reduced in LPS-ISS-susceptible BALB/c mice, but not in LPS-ISS-resistant C57BL/6 or TLR4 mutant mice, suggesting a role for reduced intestinal contraction rate in LPS-ISS susceptibility. This was tested with MnCl2, a Ca(2+) antagonist that reduced intestinal contraction rates and induced ISS, irrespective of mouse strain. Therefore, LPS-ISS is initiated by innate immune signaling that requires TLR4 and phagocytes but may be independent of TNF-α, IL-6, and NO levels. Furthermore, alteration of intestinal motility, specifically, reduced intestinal contraction rate, is a key factor in the development of ISS.

Potential intussusception risk versus benefits of rotavirus vaccination in the United States.

BACKGROUND: International data show a low-level increased risk of intussusception associated with rotavirus vaccination. Although US data have not documented a risk, we assumed a risk similar to international settings and compared potential vaccine-associated intussusception cases with benefits of prevention of rotavirus gastroenteritis by a fully implemented US rotavirus vaccine program. METHODS: To calculate excess intussusception cases, we used national data on vaccine coverage and baseline intussusception rates, and assumed a vaccine-associated intussusception relative risk of 5.3 (95% confidence interval [CI]: 3.0-9.3) in the first week after the first vaccine dose, the risk seen in international settings. We used postlicensure vaccine effectiveness data to calculate rotavirus disease burden averted. RESULTS: For a US birth cohort of 4.3 million infants, vaccine-associated intussusception could cause an excess 0.2 (range: 0.1-0.3) deaths, 45 (range: 21-86) hospitalizations and 13 (range: 6-25) cases managed in short-stay or emergency department settings. Vaccination would avert 14 (95% CI: 10-19) rotavirus-associated deaths, 53,444 (95% CI: 37,622-72,882) hospitalizations and 169,949 (95% CI: 118,161-238,630) emergency department visits. Summary benefit-risk ratios for death and hospitalization are 71:1 and 1093:1, respectively. CONCLUSIONS: The burden of severe rotavirus disease averted due to vaccination compared with the vaccine-associated intussusception events offers a side-by-side analysis of the benefits and potential risks. If an intussusception risk similar to that seen internationally exists in the United States, it is substantially exceeded by the benefits of rotavirus disease burden averted by vaccination.

Impact of rotavirus vaccines on rotavirus disease.

Rotaviruses are the most common cause of acute gastroenteritis in young children worldwide. Both licensed rotavirus vaccines (Rotarix™ [RV1] and RotaTeq™ [RV5]) are effective and safe. Studies from countries that have included RV1 or RV5 in the national immunization programs have demonstrated their safety and sustained efficacy under real-life circumstances. A significant decline in acute gastroenteritis-related deaths among Latin American children was observed after the introduction of RV1 and RV5 vaccines. Both vaccines were able to decrease the number of cases of rotavirus acute gastroenteritis and of severe rotavirus diseases. Vaccination was also associated with a dramatic reduction in hospitalizations and outpatient visits for all-cause acute gastroenteritis. Indirect protection after infant mass vaccination has been strongly suggested. Moreover, postlicensure safety studies assessed rare adverse events (rates <1 in 50,000), such as intussusception.

Trends in intussusception hospitalizations among US infants before and after implementation of the rotavirus vaccination program, 2000-2009.

BACKGROUND: Although US data have not documented an intussusception risk with current rotavirus vaccines, international data indicate a possible low risk, primarily after the first dose. METHODS: Among infants in 26 US states comprising 75% of the birth cohort, we examined age-specific trends in population-level intussusception hospitalization rates before (2000-2005) and after (2007-2009) rotavirus vaccine introduction. RESULTS: Compared with 2000-2005 (35.3 per 100,000), the rate was greater in 2007 (39.0 per 100,000; rate ratio [RR], 1.10; 95% confidence interval [CI], 1.04-1.18), similar in 2008 (33.4 per 100,000; RR, 0.95; 95% CI, .89-1.01), and lower in 2009 (32.9 per 100,000; RR, 0.93; 95% CI, .87-.99). Among infants aged 8-11 weeks, compared with 2000-2005 (6.9 per 100,000), a small, significant increase was observed in each of 2007 (11.4 per 100,000; RR, 1.64; 95% CI, 1.08-2.50), 2008 (12.2 per 100,000; RR, 1.76; 95% CI, 1.17-2.65), and 2009 (11.0 per 100,000; RR, 1.59; 95% CI, 1.04-2.44). CONCLUSIONS: Following rotavirus vaccine introduction, a small increase in intussusception rates was seen among US infants aged 8-11 weeks, to whom most first doses of vaccine are given; no sustained population-level change in overall rates was observed.

Rotavirus vaccine: a review.

Worldwide, large proportion i.e., 37% of deaths due to diarrhea in young children is attributed to rotavirus. A monovalent P1A[8] G1 vaccine and a pentavalent bovine-human reassortant vaccine human rotavirus vaccine had shown good clinical efficacy without any increase in intussusception among vaccine recipients. WHO recommends that the first dose of rotavirus vaccine should be administered to infants up to age of 6-15 weeks irrespective of the prior history of rotavirus infection and the maximum age for administering the last dose of the vaccine should be 32 weeks. Booster doses are not recommended. The current update reviews the issues related to rotavirus vaccines and their usages like milestones in the development of rotavirus vaccines, concerns regarding their efficacy and cost-effectiveness, immunity after natural infection, potential for changes in virus strains, current recommendations, post marketing surveillance, and future challenges and scope for further research regarding rotavirus vaccines.

The new pentavalent rotavirus vaccine composed of bovine (strain WC3) -human rotavirus reassortants.

BACKGROUND: Infantile gastroenteritis caused by human rotaviruses is a prevalent disease throughout the world, causing dehydration and hospitalization in all countries. In developing countries, it is associated with a high mortality. A licensed vaccine against rotavirus was withdrawn because of a causal association with intussusception. A new vaccine has been developed and is a candidate for licensure. METHODS: To recount the early development and recent demonstration of the safety and efficacy of the new vaccine. A bovine rotavirus attenuated for humans was isolated and reassorted with human rotaviruses of serotypes G1-4 and P1 to create a pentavalent vaccine. Multiple placebo-controlled clinical trials, including one involving approximately 70,000 infants, were conducted in multiple developed countries. RESULTS: The pentavalent vaccine was well tolerated by infants less than 8 months of age, and the incidence of intussusception was similar among vaccine and placebo recipients. More than 90% of infants had a significant rise in serum antirotavirus IgA titer after 3 doses. Efficacy of 95% against severe disease causing hospitalization or emergency care was demonstrated, and pentavalent vaccine prevented 74% of all rotavirus disease. CONCLUSIONS: If widely used, pentavalent vaccine would control rotavirus disease in the United States and other developed countries and could also have a major effect in developing countries.

Human rotavirus infection in infants and young children with intussusception.

Human rotavirus was detected by electron microscopy in 11 of 30 infants and young children with intussusception (37% of subjects under study). Serologic complement fixation tests revealed evidence of infection with the rotavirus in 70% of the patients examined who eliminated the rotavirus in their stools. These results indicate that human rotavirus, in addition to adenovirus, may be an infectious agent causing intussusception in infants and young children.