The leukocyte integrin antagonist Del-1 inhibits IL-17-mediated inflammatory bone loss.

Aging is linked to greater susceptibility to chronic inflammatory diseases, several of which, including periodontitis, involve neutrophil-mediated tissue injury. Here we found that aging-associated periodontitis was accompanied by lower expression of Del-1, an endogenous inhibitor of neutrophil adhesion dependent on the integrin LFA-1, and by reciprocal higher expression of interleukin 17 (IL-17). Consistent with that, IL-17 inhibited gingival endothelial cell expression of Del-1, thereby promoting LFA-1-dependent recruitment of neutrophils. Young Del-1-deficient mice developed spontaneous periodontitis that featured excessive neutrophil infiltration and IL-17 expression; disease was prevented in mice doubly deficient in Del-1 and LFA-1 or in Del-1 and the IL-17 receptor. Locally administered Del-1 inhibited IL-17 production, neutrophil accumulation and bone loss. Therefore, Del-1 suppressed LFA-1-dependent recruitment of neutrophils and IL-17-triggered inflammatory pathology and may thus be a promising therapeutic agent for inflammatory diseases.

Evolving Concepts of Pain Management in Elderly Patients.

PURPOSE OF REVIEW: The elderly population typically suffer from a variety of diseases that mostly reflect the degenerative changes linked with the aging process. These diseases may be exacerbated by acute pain or by an abrupt aggravation of previously stable chronic pain. RECENT FINDINGS: Physical and psychological changes associated with aging may influence one's experience of pain and, as a result, the severity of pain. Pain treatment in the elderly can be complex and is often a budgetary burden on the nation's health care system. These difficulties arise, in part, because of unanticipated pharmacodynamics, changed pharmacokinetics, and polypharmacy interactions. Therefore, it is critical to integrate a multidisciplinary team to develop a management strategy that incorporates medical, psychological, and surgical methods to control persistent pain conditions. It is in this critical process that pain prediction models can be of great use. The purpose of pain prediction models for the elderly is the use of mathematical models to predict the occurrence and intensity of pain and pain-related conditions. These mathematical models employ a vast quantity of data to ascertain the many risk factors for the development of pain problems in the elderly, whether said risks are adjustable or not. These models will pave the way for more informed medical decision making that are based on the findings of thousands of patients who have previously experienced the same illness and related pain conditions. However, future additional research needs to be undertaken to build prediction models that are not constrained by substantial legal or methodological limitations.

"An unprecedented occurrence: a case report of pulmonary hypertension manifestation in Donohue syndrome".

INTRODUCTION: Donohue syndrome (DS), also referred to as leprechaunism, is a remarkably uncommon autosomal recessive disorder that primarily affects the endocrine system. Its incidence rate is exceedingly low, with only 1 case reported per 4 million live births. The syndrome is distinguished by a series of characteristic clinical features. CASE PRESENTATION: We present a case of a twenty-month-old male with DS who experienced a range of dysmorphic and clinical features with the involvement of multiple systems. These features include skin hyperpigmentation, hypertrichosis, distinct facial features, abdominal distension, and microcephaly, with the involvement of the endocrine, renal, respiratory, and cardiac systems. CONCLUSION: The primary features of DS involve severe insulin resistance and growth abnormalities, the association with pulmonary hypertension (PHTN) has not been reported before. This finding adds more complexity to the condition. To the best of the author's knowledge, this is the first report for a patient with DS who has PHTN. Further investigation is required since the mechanisms behind the development of PHTN in DS are not entirely understood. Shedding light on this association will contribute to better management strategies and outcomes for affected patients.

Osteochondrolipoma of the foot treated by surgical excision: a case report and literature review.

BACKGROUND: Osteochondromas, classified as a new benign subtype of lipomas and characterised by chondroid and osseous differentiation, are rare lesions that have been infrequently reported in previous literature. The maxillofacial region was reported as the most frequent localization, with infrequent occurrence in the lower limb. This paper represents the first documented case report of osteochondrolipoma in the foot. CASE PRESENTATION: A 51-year-old male patient presented with a chief complaint of right foot pain at the plantar aspect, accompanied by the observation of swelling between the first and the second metatarsal shafts. His complaint of pain and swelling started 10 and 4 years prior, respectively. Since their onset, both symptoms have progressed in nature. Imaging revealved a large mass exhibiting a nonhomogenous composition of fibrous tissue and bony structures. Surgical intervention through total excision was indicated. CONCLUSION: Osteochodrolipoma is a benign lesion that can affect the foot leading to decreased functionality of the foot due to the pain and swelling. Surgical excision is the recommended approach for this lesion, providing both symptomatic relief and confirmation of the diagnosis through histopathological examination.

Avoidable emergency department visits among palliative care cancer patients: novel insights from Saudi Arabia and the Middle East.

BACKGROUND: Several studies emerging from developed countries have highlighted a significant number of potentially avoidable emergency department (ED) visits by cancer patients during the end-of-life period. However, there is a paucity of information from developing nations regarding palliative care practices and the utilization of the ED by palliative care patients. Herein, we aim to characterize ED admissions among patients receiving palliative care at our tertiary center in Saudi Arabia. METHODS: This is a retrospective, cross-sectional study evaluating ED visits amongst adult patients with advanced cancer who were receiving treatment under the palliative care department. This study took place over a period of 12 months from July 2021 through to July 2022. Three palliative care specialist physicians independently and blindly reviewed each patient's ED visits and determined whether the visit was avoidable or unavoidable. RESULTS: A total of 243 patients were included in the final analysis, of which 189 (78.1%) patients had unavoidable visits and 53 (21.9%) patient visits were classified as avoidable. A significantly higher proportion of breast cancer patients presented with unavoidable admissions (14.3% vs. 3.8%, P = 0.037) compared to other cancer types. The incidence of dyspnea (23.8% vs. 5.7%, P < 0.001) and fevers/chills (23.3% vs. 5.7%, P = 0.005) was significantly higher in patients with unavoidable visits. Patients with avoidable visits had a significantly greater proportion of visits for dehydration (13.2% vs. 2.1%, P = 0.002). Notably, although hospital stay was significantly longer in the unavoidable group (P = 0.045), mortality for palliative care patients-regardless of whether their ED visit was avoidable or unavoidable-was not statistically different (P=-0.069). CONCLUSION: To our knowledge, this is the largest and most comprehensive study from Saudi Arabia and the Middle East providing insights into the utilization of palliative care services in the region and the propensity of advanced cancer patients towards visiting the ED. Future studies ought to explore interventions to reduce the frequency of avoidable ED visits.

Treatment with onion bulb extract both prevents and reverses allergic inflammation in a murine model of asthma.

CONTEXT: Asthma presents a global health challenge. The main pharmacotherapy is synthetic chemicals and biological-based drugs that are costly, and have significant side effects. In contrast, use of natural products, such as onion (Allium cepa L., Amaryllidaceae) in the treatment of airway diseases has increased world-wide because of their perceived efficacy and little safety concerns. However, their pharmacological actions remain largely uncharacterized. OBJECTIVE: We investigated whether onion bulb extract (OBE) can (1) reverse established asthma phenotype (therapeutic treatment) and/or (2) prevent the development of the asthma phenotype, if given before the immunization process (preventative treatment). MATERIALS AND METHODS: Six groups of male Balb/c mice were established for the therapeutic (21 days) and five groups for the preventative (19 days) treatment protocols; including PBS and house dust mite (HDM)-challenged mice treated with vehicle or OBE (30, 60, and 100 mg/kg/i.p.). Airways inflammation was determined using cytology, histology, immunofluorescence, Western blot, and serum IgE. RESULTS: Therapeutic (60 mg/kg/i.p.) and preventative (100 mg/kg/i.p.) OBE treatment resulted in down-regulation of HDM-induced airway cellular influx, histopathological changes and the increase in expression of pro-inflammatory signaling pathway EGFR, ERK1/2, AKT, pro-inflammatory cytokines and serum IgE. DISCUSSION AND CONCLUSION: Our data show that OBE is an effective anti-inflammatory agent with both therapeutic and preventative anti-asthma effects. These findings imply that onion/OBE may be used as an adjunct therapeutic agent in established asthma and/or to prevent development of allergic asthma. However, further studies to identify the active constituents, and demonstrate proof-of-concept in humans are needed.

Can the current monkeypox affect the heart? A systematic review of case series and case report.

BACKGROUND: Monkeypox is a zoonotic viral infection first reported in May 2022. Monkeypox cases present with prodromal symptoms, rash, and/or systemic complications. This study systematically reviews the monkeypox cases presented with any cardiac complications. METHODS: A systematic literature search was done to locate papers that discuss any cardiac complications associated with monkeypox; then, data were analyzed qualitatively. RESULTS: Nine articles, including the 13 cases that reported cardiac complications of the disease, were included in the review. Five cases previously had sex with men, and two cases had unprotected intercourse, which reveals the importance of the sexual route in disease transmission. All cases have a wide spectrum of cardiac complications, such as acute myocarditis, pericarditis, pericardial effusion, and myopericarditis. CONCLUSION: This study clarifies the potential for cardiac complications in monkeypox cases and provides avenues for future research to determine the underlying mechanism. Also, we found that the cases with pericarditis were treated with colchicine, and those with myocarditis were treated with supportive care or cardioprotective treatment (Bisoprolol and Ramipril). Furthermore, Tecovirimat is used as an antiviral drug for 14 days.

Early versus late discharge after transcatheter aortic valve replacement and readmissions for permanent pacemaker implantation.

OBJECTIVE: To examine the rate of readmission for permanent pacemaker (PPM) implantation with early versus late discharge after transcatheter aortic valve replacement (TAVR). BACKGROUND: There is a current trend toward early discharge after TAVR. However, paucity of data exists on the impact of such practice on readmissions for PPM implantation. METHODS: The Nationwide Readmission Database 2016-2018 was queried for all hospitalizations where patients underwent TAVR. Hospitalizations were stratified into early (Days 0 and 1) versus late (≥Day 2) discharge groups. Observations in which PPM was required in the index admission were excluded. Multivariable regression analyses involving patient- and hospital-related variables were utilized. The primary outcome was 90-day readmission for PPM implantation. RESULTS: The final analysis included 68,482 TAVR hospitalizations, 20,261 (29.6%) with early versus 48,221 (70.4%) with late discharge. Early discharge after TAVR increased over the study period (16.2% in 2016 vs. 37.9% in 2018, Ptrend < 0.01). Nevertheless, 90-day readmission for PPM implantation remained stable (1.8% in 2016 vs. 2.0% in 2018, Ptrend = 0.32). The 90-day readmission rate for PPM implantation (2.0% vs. 1.8%; adjusted odds ratio: 1.15; 95% confidence interval: 0.95-1.39; p = 0.15) and median time-to-readmission (5 days [interquartile range, IQR 3-9] vs. 5 days [IQR 3-14], p = 0.92) were similar with early versus late discharge. Similar rates were observed regardless of whether readmission was elective versus not. Early discharge was associated with lower hospitalization cost ($39,990 ± $13,681 vs. $46,750 ± $18,218, p < 0.01) compared with late discharge. CONCLUSION: In patients who did not require PPM during the index TAVR hospitalization, the rate of readmission for PPM implantation was similar with early versus late discharge.

Chronic liver disease in homeless individuals and performance of non-invasive liver fibrosis and injury markers: VALID study.

BACKGROUND/AIMS: Community-based assessment and management of chronic liver disease (CLD) in people who are homeless (PWAH) remain poorly described. We aimed to determine prevalence/predictors of CLD in PWAH and assess the performance of non-invasive liver fibrosis and injury markers. METHODS: The Vulnerable Adult LIver Disease (VALID) study provided a "one-stop" liver service based at homeless hostels. Our primary outcome was the prevalence of clinically significant hepatic fibrosis (CSHF; liver stiffness measurement (LSM) ≥8 kPa). RESULTS: Total individuals recruited were 127, mean ± SD age 47 ± 9.4 years, 50% (95% CI 41%-59%) and 39% (95% CI 31%-48%) having alcohol dependence and a positive HCV RNA respectively. CSHF was detected in 26% (95% CI 17%-35%), independent predictors being total alcohol unit/week (OR 1.01, 95% CI 1.00-1.02, P = .002) and HCV RNA positivity (OR 2.93, 95% CI 1.12-7.66, P = .029). There was moderate agreement between LSM and Enhanced Liver Fibrosis (ELF) score (kappa 0.536, P < .001) for CSHF as assessed by LSM ≥8 kPa. Those with CSHF had significantly higher levels of IFN-γ (P = .002), IL-6 (P = .001), MMP-2 (P = .006), ccCK-18 (P < .001) and ELF biomarkers (P < .001), compared to those without CSHF. Service uptake was ≥95%. Direct acting antiviral (DAA) treatment completion was 93% (95% CI 77%-99%), sustained virological response (SVR) being 83% (95% CI 64%-94%). CONCLUSION: There is a significant liver disease burden from HCV and alcohol in PWAH. Non-invasive liver fibrosis and injury markers can help in identifying such individuals in the community. Despite a challenging cohort, excellent service uptake and high DAA-based SVRs can be achieved.

The COVID-19 Pandemic: A Health Crisis Managed or a Panic Response with Disastrous Future Consequences?

In 1 year, COVID-19 spread rapidly worldwide affecting all societies and most age-groups. It has taken not only a toll of human lives (approaching 220 million people infected with 4.55 million reported deaths at time of writing) but also decimated every economy as countries struggle to control infection rates by introducing draconian lockdown and social distancing measures, bringing great suffering well beyond medical effects of the disease. A parallel pandemic has resulted in a deluge of information emanating from both scientific as well as international news media including social media platforms. Fact and fiction, reality, and perception have become entangled; the only realistic solution, both medically as well as politically, is concerted global vaccination (which is currently underway) to reduce further infection by introducing universal immunity. However, public controversy rages due to widespread apprehension regarding necessity, immediate risks, and long-term safety of what is perceived as "fast-tracked" medication. While some concerns may be justified, much is due to misconception and misunderstanding. This review highlights some of the issues concerning the handling of the COVID-19 crisis by governments worldwide, the medical and scientific communities, and the media and how this may have laid the foundations for a far greater medical, social, and economic burden in the coming years. We present comparative data to challenge current conceptions of this disease in the more general context of human health to provide a perspective that seems to have been lost in the general panic. We need more rational approaches to the handling of a disease which is unlikely to disappear from our spectrum of afflictions even after the magnifying glass has been removed.

The Effect of Delivery Systems on the Induction of T Helper 1 Cell Response to an ESAT6-Like Protein Rv3619c and Identification of Its Immunodominant Peptides.

OBJECTIVE: This study determined the effects of chemical adjuvants, incomplete Freund's adjuvant (IFA) and aluminum hydroxide (Alum), mycobacteria, and a DNA plasmid as delivery systems on the induction of protective Th1 (interferon-gamma (IFN-γ)) and nonprotective Th2 (IL-5) and Treg (IL-10) cytokine responses to Rv3619c and its peptides. Rv3619c is an immunodominant Mycobacterium tuberculosis-specific antigen and belongs to the early-secreted antigenic target of 6 kDa-family of proteins. Delivery systems are needed to deliver such antigens in animal models and induce protective immune responses. METHODS: The rv3619c gene was amplified from the genomic DNA of M. tuberculosis and cloned into appropriate vectors for expression in Escherichia coli, Mycobacterium smegmatis, and eukaryotic cells. Spleen cells from mice immunized with rv3619c using different delivery systems were stimulated in vitro with synthetic peptides (P1 to P6) of Rv3619c, and secreted cytokines were estimated by ELISA. RESULTS: The recombinant M. smegmatis and DNA plasmid induced the secretion of the protective cytokine IFN-γ in response to peptide-pool of Rv3619c and all the individual peptides, whereas rv3619c/IFA induced the secretion of IFN-γ in response to the peptide pool, and the peptides P5 and P6. However, the secretions of the nonprotective cytokines IL-5 and IL-10 were induced to none of the peptides with the delivery systems used. CONCLUSION: Rv3619c is a major antigen of M. tuberculosis with multiple immunogenic epitopes; however, immune responses to individual epitopes can vary based on delivery systems used.

Prostaglandin E2 sensitizes the cough reflex centrally via EP3 receptor-dependent activation of NaV 1.8 channels.

BACKGROUND: Cough hypersensitivity is a major characteristic feature associated with several types of cough, including chronic cough, but its underlying mechanisms remain to be fully understood. Inflammatory mediators, such as prostaglandin E2 (PGE2), have been implicated in both peripheral induction and sensitization of the cough reflex. In this study, using a conscious guinea pig model of cough, we investigated whether PGE2 can sensitize the cough reflex via central actions and, if so, via which mechanisms. METHODS: All drugs were administered by intracerebroventricular (i.c.v.) route and whole-body plethysmograph set-up was used for both induction, using aerosolized citric acid (0.2 M), and recording of cough. Immunohistochemistry was performed to confirm the expression of NaV 1.8 channels in the nucleus tractus solitarius (nTS). RESULTS: We show that both PGE2 and the non-selective EP1/EP3 agonist, sulprostone, dose-dependently enhanced the citric acid-induced cough (P ≤ 0.001, P ≤ 0.01, respectively). Pretreatment with the EP1 antagonist, ONO-8130, did not affect the sulprostone-induced cough sensitization, whilst the EP3 antagonist, L-798,106, dose-dependently inhibited this effect (P ≤ 0.05). Furthermore, treatment with either the EP2 agonist, butaprost or the EP4 agonist, L-902,688, had no effect on cough sensitization. Additionally, pretreatment with either the TRPV1 antagonist, JNJ-17203212 or the TRPA1 antagonist, HC-030031, alone or in combination, nor with the NaV 1.1, 1.2, 1.3, 1.4, 1.6 and 1.7 channel blocker, tetrodotoxin, had any effect on the cough. In contrast, pretreatment with the NaV 1.8 antagonist, A-803467, dose-dependently inhibited this effect (P ≤ 0.05). Furthermore, NaV 1.8 channels were shown to be expressed in the nTS. CONCLUSION: Collectively, our findings show that PGE2 sensitizes the cough reflex centrally via EP3 receptor-dependent activation of NaV 1.8 but independently of TRPV1,TRPA1 and TTX-sensitive sodium channel activation. These results indicate that PGE2 plays an important role in central sensitization of the cough reflex and suggest that central EP3 receptors and/or NaVv 1.8 channels may represent novel antitussive molecular targets.

The transcription factor T-bet regulates intestinal inflammation mediated by interleukin-7 receptor+ innate lymphoid cells.

Mice lacking the transcription factor T-bet in the innate immune system develop microbiota-dependent colitis. Here, we show that interleukin-17A (IL-17A)-producing IL-7Rα(+) innate lymphoid cells (ILCs) were potent promoters of disease in Tbx21(-/-)Rag2(-/-) ulcerative colitis (TRUC) mice. TNF-α produced by CD103(-)CD11b(+) dendritic cells synergized with IL-23 to drive IL-17A production by ILCs, demonstrating a previously unrecognized layer of cellular crosstalk between dendritic cells and ILCs. We have identified Helicobacter typhlonius as a key disease trigger driving excess TNF-α production and promoting colitis in TRUC mice. Crucially, T-bet also suppressed the expression of IL-7R, a key molecule involved in controlling intestinal ILC homeostasis. The importance of IL-7R signaling in TRUC disease was highlighted by the dramatic reduction in intestinal ILCs and attenuated colitis following IL-7R blockade. Taken together, these data demonstrate the mechanism by which T-bet regulates the complex interplay between mucosal dendritic cells, ILCs, and the intestinal microbiota.

Noninvasive Assessment of Schistosoma-Related Periportal Fibrosis.

Schistosomiasis affects nearly 250 million individuals in the world. Hepatosplenic schistosomiasis (HSS) results in periportal fibrosis (PPF) and portal hypertension (pHTN). Ultrasound has been extensively used for the diagnosis of Schistosoma-related PPF and a number of staging methods have been validated for this purpose such as Strickland classification and Niamey protocol. Nevertheless, the application of noninvasive techniques, particularly elastography modalities, has not been well explored. In this review, we describe the various noninvasive diagnostic tools for assessment of Schistosoma-related PPF including US parameters, serum biomarkers, and US-based elastography techniques. While elastography techniques have demonstrated value in the evaluation of HSS, the evidence remains limited with most studies recruiting a small number of patients. Longitudinal studies with larger sample size are required in order to devise robust criteria to accurately assess the performance of noninvasive techniques in the prediction of both regression and progression of the degree of PPF and identify their cost-effectiveness in community screening.

Bradykinin sensitizes the cough reflex via a B2 receptor dependent activation of TRPV1 and TRPA1 channels through metabolites of cyclooxygenase and 12-lipoxygenase.

BACKGROUND: Inhaled bradykinin (BK) has been reported to both sensitize and induce cough but whether BK can centrally sensitize the cough reflex is not fully established. In this study, using a conscious guinea-pig model of cough, we investigated the role of BK in the central sensitization of the cough reflex and in airway obstruction. METHODS: Drugs were administered, to guinea pigs, by the intracerebroventricular (i.c.v.) route. Aerosolized citric acid (0.2 M) was used to induce cough in a whole-body plethysmograph box, following i.c.v. infusion of drugs. An automated analyser recorded both cough and airway obstruction simultaneously. RESULTS: BK, administered by the i.c.v. route, dose-dependently enhanced the citric acid-induced cough and airway obstruction. This effect was inhibited following i.c.v. pretreatment with a B2 receptor antagonist, TRPV1 and TRPA1 channels antagonists and cyclooxygenase (COX) and 12-lipoxygenase (12-LOX) inhibitors. Furthermore, co-administration of submaximal doses of the TRPV1 and TRPA1 antagonists or the COX and 12-LOX inhibitors resulted in a greater inhibition of both cough reflex and airway obstruction. CONCLUSIONS: Our findings show that central BK administration sensitizes cough and enhances airway obstruction via a B2 receptor/TRPV1 and/or TRPA1 channels which are coupled via metabolites of COX and/or 12-LOX enzymes. In addition, combined blockade of TRPV1 and TRPA1 or COX and 12-LOX resulted in a greater inhibitory effect of both cough and airway obstruction. These results indicate that central B2 receptors, TRPV1/TRPA1 channels and COX/12-LOX enzymes may represent potential therapeutic targets for the treatment of cough hypersensitivity.

Permanent indwelling peritoneal catheters for palliation of refractory ascites in end-stage liver disease: A systematic review.

BACKGROUND & AIMS: The incidence and mortality from end-stage liver disease is increasing, with a minority eligible for liver transplantation. Ascites is the commonest complication of end-stage liver disease and large volume paracentesis (LVP) the accepted management strategy where refractory to medical treatment. In malignant ascites, permanent indwelling peritoneal catheters (PIPC) are an established palliative intervention. The aims are to describe available data using permanent indwelling peritoneal catheters in refractory ascites due to end-stage liver disease. METHODS: Using systematic review methodology, databases were searched (MEDLINE, EMBASE, CINAHL [The Cumulative Index to Nursing and Allied Health Literature], Google Scholar and Cochrane Database of Systematic Reviews from inception-March 2018), for studies combining ascites and palliative care. Inclusion and exclusion criteria were applied to results. RESULTS: Following initial and updated searches, 225 studies were identified for full text review, 18 were eligible for final analysis. The studies displayed heterogeneity in design, reported on different indwelling catheters and were overall of low quality. Only one pilot randomised controlled trial was identified, of PIPC versus LVP, recruiting one patient into each arm. Technical insertion success was 100%, with low rates of non-infectious complications (<12%), none life threatening. Rates of bacterial peritonitis were not unacceptably high (12.7%), considering this was an end-stage liver disease population and only a minority utilising long-term prophylactic antibiotics. Only one study attempted quality-of-life assessments; none addressed potential health economic benefits. CONCLUSIONS: Despite lack of well-designed studies, preliminary data suggests low significant complication rates; however safety and efficacy of permanent indwelling peritoneal catheters in end-stage liver disease remains to be confirmed. Further prospective randomised controlled trials are warranted, potentially translating permanent indwelling peritoneal catheters into improved palliative care in end-stage liver disease.

Chronic administration of nano-sized PAMAM dendrimers in vivo inhibits EGFR-ERK1/2-ROCK signaling pathway and attenuates diabetes-induced vascular remodeling and dysfunction.

We investigated whether chronic administration of nano-sized polyamidoamine (PAMAM) dendrimers can have beneficial effects on diabetes-induced vascular dysfunction by inhibiting the epidermal growth factor receptor (EGFR)-ERK1/2-Rho kinase (ROCK)-a pathway known to be critical in the development of diabetic vascular complications. Daily administration of naked PAMAMs for up to 4 weeks to streptozotocin-induced diabetic male Wistar rats inhibited EGFR-ERK1/2-ROCK signaling and improved diabetes-induced vascular remodeling and dysfunction in a dose, generation (G6 > G5) and surface chemistry-dependent manner (cationic > anionic > neutral). PAMAMs, AG1478 (a selective EGFR inhibitor), or anti-EGFR siRNA also inhibited vascular EGFR-ERK1/2-ROCK signaling in vitro. These data showed that naked PAMAM dendrimers have the propensity to modulate key (e.g. EGFR) cell signaling cascades with associated pharmacological consequences in vivo that are dependent on their physicochemical properties. Thus, PAMAMs, alone or in combination with vasculoprotective agents, may have a beneficial role in the potential treatment of diabetes-induced vascular complications.

LptO (PG0027) Is Required for Lipid A 1-Phosphatase Activity in Porphyromonas gingivalis W50.

Porphyromonas gingivalis produces outer membrane vesicles (OMVs) rich in virulence factors, including cysteine proteases and A-LPS, one of the two lipopolysaccharides (LPSs) produced by this organism. Previous studies had suggested that A-LPS and PG0027, an outer membrane (OM) protein, may be involved in OMV formation. Their roles in this process were examined by using W50 parent and the ΔPG0027 mutant strains. Inactivation of PG0027 caused a reduction in the yield of OMVs. Lipid A from cells and OMVs of P. gingivalis W50 and the ΔPG0027 mutant strains were analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Lipid A from W50 cells contained bis-P-pentaacyl, mono-P-pentaacyl, mono-P-tetraacyl, non-P-pentaacyl, and non-P-tetraacyl species, whereas lipid A from ΔPG0027 mutant cells contained only phosphorylated species; nonphosphorylated species were absent. MALDI-TOF/TOF tandem MS of mono-P-pentaacyl (m/z 1,688) and mono-P-tetraacyl (m/z 1,448) lipid A from ΔPG0027 showed that both contained lipid A 1-phosphate, suggesting that the ΔPG0027 mutant strain lacked lipid A 1-phosphatase activity. The total phosphatase activities in the W50 and the ΔPG0027 mutant strains were similar, whereas the phosphatase activity in the periplasm of the ΔPG0027 mutant was lower than that in W50, supporting a role for PG0027 in lipid A dephosphorylation. W50 OMVs were enriched in A-LPS, and its lipid A did not contain nonphosphorylated species, whereas lipid A from the ΔPG0027 mutant (OMVs and cells) contained similar species. Thus, OMVs in P. gingivalis are apparently formed in regions of the OM enriched in A-LPS devoid of nonphosphorylated lipid A. Conversely, dephosphorylation of lipid A through a PG0027-dependent process is required for optimal formation of OMVs. Hence, the relative proportions of nonphosphorylated and phosphorylated lipid A appear to be crucial for OMV formation in this organism.IMPORTANCE Gram-negative bacteria produce outer membrane vesicles (OMVs) by "blebbing" of the outer membrane (OM). OMVs can be used offensively as delivery systems for virulence factors and defensively to aid in the colonization of a host and in the survival of the bacterium in hostile environments. Earlier studies using the oral anaerobe Porphyromonas gingivalis as a model organism to study the mechanism of OMV formation suggested that the OM protein PG0027 and one of the two lipopolysaccharides (LPSs) synthesized by this organism, namely, A-LPS, played important roles in OMV formation. We suggest a novel mechanism of OMV formation in P. gingivalis involving dephosphorylation of lipid A of A-LPS controlled/regulated by PG0027, which causes destabilization of the OM, resulting in blebbing and generation of OMVs.