COVID-19 and Africa: Surviving between a rock and a hard place.

With over 575,000 deaths and about 13.3 million cases globally, the COVID-19 pandemic has had a terrible impact globally during the 6 months since cases were first detected in China. Conscious of the many challenges presented in settings with abundance of resources and with robust health systems, where mortality has been significant and transmission difficult to control, there was a logical concern to see how the virus could impact African countries, and their fragile and weak health systems.

[COVID-19 and Africa: Surviving between a rock and a hard place].

With over 575,000 deaths and about 13.3 million cases globally, the COVID-19 pandemic has had a terrible impact globally during the 6 months since cases were first detected in China. Conscious of the many challenges presented in settings with abundance of resources and with robust health systems, where mortality has been significant and transmission difficult to control, there was a logical concern to see how the virus could impact African countries, and their fragile and weak health systems.

Polybacterial Periodontal Pathogens Alter Vascular and Gut BH4/nNOS/NRF2-Phase II Enzyme Expression.

Periodontal disease is a highly prevalent chronic inflammatory disease and is associated with complex microbial infection in the subgingival cavity. Recently, American Heart Association supported a century old association between periodontal disease and atherosclerotic vascular disease. We have recently shown that polybacterial periodontal infection led to aortic atherosclerosis and modulation of lipid profiles; however the underlying mechanism(s) has not been yet demonstrated.

Myxomavirus anti-inflammatory chemokine binding protein reduces the increased plaque growth induced by chronic Porphyromonas gingivalis oral infection after balloon angioplasty aortic injury in mice.

Thrombotic occlusion of inflammatory plaque in coronary arteries causes myocardial infarction. Treatment with emergent balloon angioplasty (BA) and stent implant improves survival, but restenosis (regrowth) can occur. Periodontal bacteremia is closely associated with inflammation and native arterial atherosclerosis, with potential to increase restenosis.

Active invasion of Porphyromonas gingivalis and infection-induced complement activation in ApoE-/- mice brains.

Periodontal disease is a polymicrobial inflammatory disease that leads to chronic systemic inflammation and direct infiltration of bacteria/bacterial components, which may contribute to the development of Alzheimer's disease. ApoE-/- mice were orally infected (n = 12) with Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Fusobacterium nucleatum as mono- and polymicrobial infections. ApoE-/- mice were sacrificed following 12 and 24 weeks of chronic infection.

Active invasion of oral and aortic tissues by Porphyromonas gingivalis in mice causally links periodontitis and atherosclerosis.

Atherosclerotic vascular disease is a leading cause of myocardial infarction and cerebrovascular accident, and independent associations with periodontal disease (PD) are reported. PD is caused by polymicrobial infections and aggressive immune responses. Genomic DNA of Porphyromonas gingivalis, the best-studied bacterial pathogen associated with severe PD, is detected within atherosclerotic plaque.

Bis-enoxacin blocks rat alveolar bone resorption from experimental periodontitis.

Periodontal diseases are multifactorial, caused by polymicrobial subgingival pathogens, including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Chronic periodontal infection results in inflammation, destruction of connective tissues, periodontal ligament, and alveolar bone resorption, and ultimately tooth loss. Enoxacin and a bisphosphonate derivative of enoxacin (bis-enoxacin) inhibit osteoclast formation and bone resorption and also contain antibiotic properties.

Invasion of oral and aortic tissues by oral spirochete Treponema denticola in ApoE(-/-) mice causally links periodontal disease and atherosclerosis.

Treponema denticola is a predominantly subgingival oral spirochete closely associated with periodontal disease and has been detected in atherosclerosis. This study was designed to evaluate causative links between periodontal disease induced by chronic oral T. denticola infection and atherosclerosis in hyperlipidemic ApoE(-/-) mice.

Polymicrobial infection with major periodontal pathogens induced periodontal disease and aortic atherosclerosis in hyperlipidemic ApoE(null) mice.

Periodontal disease (PD) and atherosclerosis are both polymicrobial and multifactorial and although observational studies supported the association, the causative relationship between these two diseases is not yet established. Polymicrobial infection-induced periodontal disease is postulated to accelerate atherosclerotic plaque growth by enhancing atherosclerotic risk factors of orally infected Apolipoprotein E deficient (ApoE(null)) mice. At 16 weeks of infection, samples of blood, mandible, maxilla, aorta, heart, spleen, and liver were collected, analyzed for bacterial genomic DNA, immune response, inflammation, alveolar bone loss, serum inflammatory marker, atherosclerosis risk factors, and aortic atherosclerosis.

Polymicrobial infection with periodontal pathogens specifically enhances microRNA miR-146a in ApoE-/- mice during experimental periodontal disease.

Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia are periodontal pathogens associated with the etiology of adult periodontitis as polymicrobial infections. Recent studies demonstrated that oral infection with P. gingivalis induces both periodontal disease and atherosclerosis in hyperlipidemic and proatherogenic ApoE(-/-) mice.

Role of Porphyromonas gingivalis phosphoserine phosphatase enzyme SerB in inflammation, immune response, and induction of alveolar bone resorption in rats.

Porphyromonas gingivalis secretes a serine phosphatase enzyme, SerB, upon contact with gingival epithelial cells in vitro. The SerB protein plays a critical role in internalization and survival of the organism in epithelial cells. SerB is also responsible for the inhibition of interleukin-8 (IL-8) secretion from gingival epithelial cells infected with P.

Role for beta1 integrins in cortical osteocytes during acute musculoskeletal disuse.

The mammalian skeleton adjusts bone structure and strength in response to changes in mechanical loading, however the molecular and cellular mechanisms governing this process in vivo are unknown. Terminally differentiated osteoblasts, the osteocytes, are presumptive mechanosensory cells for bone, and cell culture studies demonstrate that beta1 integrins participate in mechanical signaling. To determine the role of beta1 integrins in osteoblasts in vivo, we used the Cre-lox system to delete beta1 integrin from cells committed to the osteoblast lineage.

CcpA regulates central metabolism and virulence gene expression in Streptococcus mutans.

CcpA globally regulates transcription in response to carbohydrate availability in many gram-positive bacteria, but its role in Streptococcus mutans remains enigmatic. Using the fructan hydrolase (fruA) gene of S. mutans as a model, we demonstrated that CcpA plays a direct role in carbon catabolite repression (CCR).

Effects of basic fibroblast growth factor and a prostaglandin E2 receptor subtype 4 agonist on osteoblastogenesis and adipogenesis in aged ovariectomized rats.

Unlabelled: bFGF stimulates osteo- and adipogenesis concurrently at skeletal sites with red but not with fatty marrow, whereas a PGE2 receptor subtype 4 agonist has bone anabolic effects at both skeletal sites and decreases adipose tissue within red and fatty marrow.

Introduction: Basic fibroblast growth factor (bFGF) stimulates osteogenesis at skeletal sites with hematopoietic but not with fatty marrow. The prostaglandin E2 (PGE2) receptor subtype 4 agonist (EP4A) stimulates osteogenesis at the former skeletal sites, but its effects at fatty marrow sites are unknown.

PTH stimulates bone formation in mice deficient in Lrp5.

Unlabelled: Lrp5 deficiency decreases bone formation and results in low bone mass. This study evaluated the bone anabolic response to intermittent PTH treatment in Lrp5-deficient mice. Our results indicate that Lrp5 is not essential for the stimulatory effect of PTH on cancellous and cortical bone formation.