Short chain fatty acids may elicit an innate immune response from preadipocytes: a potential link between bacterial infection and inflammatory diseases

Short chain fatty acids (SCFAs) such as acetate, propionate and butyrate are produced by bacterial fermentation of dietary fiber. The highest concentrations of SCFAs in the body are found in the colon. Elevated dietary acetate has been shown to have anti-inflammatory effects in mouse models of colitis and inflammatory diseases in peripheral tissues. The details of how dietary SCFAs stimulate reduced inflammation in peripheral tissues have not been determined. I suggest that SCFA concentrations in peripheral tissues are generally not sufficient to locally produce a significant anti-inflammatory effect from immune cells. Moreover it is possible that elevated SCFA levels in peripheral tissues may actually stimulate an inflammatory response. The hypothesis is presented that preadipocytes and other cells with immune function such as fibroblasts in peripheral tissues elicit an inflammatory innate immune response when exposed to SCFAs at millimolar concentrations. A role for SCFAs in activating an immune response in preadipocytes is possible given the expression of a SCFA receptor in these cells, the demonstration that adipocytes and preadipocytes have immunity related functions, the observation that 2mM SCFAs stimulated the expression of monocyte chemoattractant protein-1 (MCP-1) mRNA from 3T3-L1 preadipocytes and that concentrations of SCFAs can reach elevated levels at sites of bacterial infection. A SCFA-induced inflammatory response from preadipocytes and other cells with immune function, such as fibroblasts, may provide a further contributing factor linking bacterial infection to the development of insulin resistance and the severity of inflammatory diseases such as atherosclerosis.     

Inhibition of polymorphonuclear leukocyte chemotaxis by streptokinase-streptodornase

Leukotaxis of circulating polymorphonuclear leukocytes (PMN's) appears to be a critical step in the generation of local inflammatory reactions. The present studies demonstrate a reversible, dose-dependent inhibition of PMN chemotaxis by streptokinase-streptodornase (SK-SD). This inhibition does not appear to depend upon the presence of lymphocytes or the release of chemokinetic humoral factors and phagocytic and bactericidal capacities of PMN's are unaffected by the doses of SK-SD employed.     

Microbiologic response to treatment of bacterial vaginosis with topical clindamycin or metronidazole

To compare the frequencies, concentrations, and antimicrobial susceptibilities of vaginal microbes isolated from women with bacterial vaginosis (BV) before and after therapy, 119 nonpregnant women aged 18 to 45 with clinical and Gram stain evidence of BV were randomized to receive intravaginal clindamycin or metronidazole. Vaginal swabs were collected at baseline and 7 to 12 days, 35 to 45 days, and 70 to 90 days following therapy for quantitative vaginal culture. For the 99 women completing all four visits, statistical analyses were performed comparing differences in vaginal microflora between the two treatment arms and between visits in the same treatment group. Antimicrobial susceptibility testing using the agar dilution method was performed for anaerobic gram-negative rods. Although both therapies resulted in decreased colonization by Gardnerella vaginalis and Mycoplasma hominis, only metronidazole treatment resulted in a significant decrease in the frequency and concentration of Prevotella bivia and black-pigmented Prevotella species. Of the 865 anaerobic gram-negative rods evaluated for susceptibility, only 3 (0.3%) were resistant to metronidazole, whereas clindamycin resistance increased significantly for P. bivia and black-pigmented anaerobic gram-negative rods persisting following clindamycin therapy. Clindamycin-resistant subpopulations of P. bivia and black-pigmented Prevotella species emerged 7 to 12 days after therapy even among women colonized initially by clindamycin-susceptible strains. These resistant subpopulations persisted at high frequencies (42 to 50%) 70 to 90 days following therapy. The two topical agents for treatment of BV have differing microbiologic effects on the vaginal microflora. The emergence of clindamycin-resistant anaerobic gram-negative rods following therapy is of concern.     

Plasma-assisted surface modification of organic biopolymers to prevent bacterial attachment

Despite many synthetic biomaterials having physical properties that are comparable or even superior to those of natural body tissues, they frequently fail due to the adverse physiological reactions they cause within the human body, such as infection and inflammation. The surface modification of biomaterials is an economical and effective method by which biocompatibility and biofunctionality can be achieved while preserving the favorable bulk characteristics of the biomaterial, such as strength and inertness. Amongst the numerous surface modification techniques available, plasma surface modification affords device manufacturers a flexible and environmentally friendly process that enables tailoring of the surface morphology, structure, composition, and properties of the material to a specific need. There are a vast range of possible applications of plasma modification in biomaterial applications, however, the focus of this review paper is on processes that can be used to develop surface morphologies and chemical structures for the prevention of adhesion and proliferation of pathogenic bacteria on the surfaces of in-dwelling medical devices. As such, the fundamental principles of bacterial cell attachment and biofilm formation are also discussed. Functional organic plasma polymerised coatings are also discussed for their potential as biosensitive interfaces, connecting inorganic/metallic electronic devices with their physiological environments.     

Prevalence of bacterial vaginosis in antenatal women

Bacterial vaginosis is an established risk factor in pregnant women for premature rupture of membranes and preterm delivery. This study was carried out to find out the prevalence of Bacterial Vaginosis (BV) in antenatal women with vaginal discharge and the effect of treatment with Metronidazole gel on pregnancy outcome. One hundred and fifty symptomatic and fifty asymptomatic women in second trimester of pregnancy in the age group of 20-30 years were included in the study. Gram stained smears of vaginal discharge were examined for evidence of BV with a scoring system by Nugent et al and was found to be positive in 38.5% in symptomatic antenatal women. Intravaginal metronidazole gel application was found to be an effective therapeutic option. Incidence of preterm labour was more in untreated cases.     

Inhibition of human eosinophil chemotaxis by IgA paraproteins

Sera from patients with IgA myeloma inhibit normal human eosinophil chemotaxis. No correlation was noted between inhibition and the absolute concentration of IgA or - light-chain type. Eosinophil chemotactic inhibitory activity was associated with isolated IgA paraproteins and was found to be cell directed and stable at 56° C. Pepsin digestion of IgA paraproteins resulted in loss of both IgA Fc fragment and eosinophil chemotactic inhibitory activity. Polymeric IgA accounted for most of the inhibitory activity as evidenced by sucrose density gradient centrifugation studies and a loss of inhibitory activity following dithiothrietol reduction and iodoacetamide alkylation which converted polymeric IgA to monomeric IgA. Comparative studies with neutrophils showed that both neutrophil and eosinophil chemotaxis and chemokinesis were effectively inhibited by IgA paraproteins. The mechanisms of suppression of eosinophil and neutrophil chemotaxis by IgA paraproteins appear to be similar and possibly may involve a membrane receptor for IgA.     

Inhibition of eosinophil chemotaxis by a new antiallergic compound (cetirizine)

The in vivo inhibitory effect of a new antiallergic, anti-H1 drug, cetirizine, on eosinophil attraction at skin sites challenged with various stimuli has been recently suggested. In the present work, we confirmed that this molecule, at therapeutical concentration, has a potent inhibitory action on eosinophil response to different chemoattractant mediators such as platelet-activating factor (PAF acether) and N-formyl methionyl leucyl phenyl alanyl in vitro. Another anti-H1 drug, polaramine, did not show this effect at the same concentration. These findings suggest that cetirizine in addition to its antihistaminic effect could also play a direct inhibitory effect on eosinophil recruitment. Moreover, cetirizine was not toxic for eosinophils and did not induce degranulation, as shown by the absence of peroxidase release. Comparison between cetirizine and a PAF acether antagonist (BN 52021) suggested that cetirizine did not act by a PAF receptor-blocking activity.     

Inhibition by histamine of platelet-activating-factor-induced neutrophil chemotaxis in bronchial asthma

Circulating human polymorphonuclear neutrophils are involved in asthma after their migration into the lung by local chemotactic factors. Investigation of the locomotion of neutrophils in Boyden chambers, showed that the chemotactic intensity of the platelet-activating factor (PAF) was similar in cells from healthy subjects and allergic asthmatics, although the optimal effect of the mediator was observed at 10(-6) M and 10(-8) M, respectively. Histamine had no direct chemoattractant effect on neutrophils but inhibited PAF-induced chemotaxis of neutrophils from healthy subjects and allergic asthmatics. This study provides additional evidence that neutrophils are involved in asthma, and points out the interaction between PAF and histamine in the migration of neutrophils to the lung.     

Dendritic cell activation and maturation induced by mucosal fluid from women with bacterial vaginosis

Dendritic cells (DC) at mucosal surfaces mature when exposed to "danger" signals such as LPS. Bacterial vaginosis (BV) is a prevalent alteration of the vaginal bacterial flora associated with preterm childbirth and increased risk for HIV acquisition. We examined the effect of mucosal fluid from women with BV or healthy flora on DC function. IL-12, IL-23 and p40 production by monocyte-derived dendritic cells (MDDC) were all induced by BV samples. Activation/maturation markers HLA-DR, CD40 and CD83 on MDDC incubated with BV CVL were also induced. BV CVL also decreased the endocytic ability of MDDC and increased proliferation of T cells in allogeneic MLR. Plasmacytoid dendritic cell (pDC) CD86 expression was induced by BV CVL. Healthy flora CVL had little effect in any of the tests. This study suggests that BV, but not healthy flora, affects local dendritic cell function in vivo suggesting a mechanism through which BV affects mucosal immunity.     

Reversible deficiency of antimicrobial polypeptides in bacterial vaginosis

Bacterial vaginosis is a common condition associated with increased risk of sexually transmitted diseases, including human immunodeficiency virus infections. In contrast, vulvovaginal candidiasis has a much weaker association with sexually transmitted diseases. We found that vaginal lavage fluid from women with bacterial vaginosis is deficient in antimicrobial polypeptides and antimicrobial activity compared to fluid from healthy women or women with vulvovaginal candidiasis. Effective treatment normalized the concentrations of antimicrobial polypeptides in both bacterial vaginosis and in vulvovaginal candidiasis, suggesting that the abnormalities were a result of the diseases. Unlike in vulvovaginal candidiasis, the neutrophil attractant chemokine interleukin-8 (IL-8) was not increased in bacterial vaginosis, accounting for low concentrations of neutrophil-derived defensins in vaginal fluid. In organotypic cultures of human vaginal epithelium containing dendritic cells, treatment with Lactobacillus jensenii, a typical vaginal resident, induced the synthesis of IL-8 mRNA and the epithelial human beta-defensin-2 mRNA, but a typical bacterial vaginosis pathogen, Gardnerella vaginalis, had no effect. When the two bacteria were combined, Gardnerella vaginalis did not interfere with the immunostimulatory effect of Lactobacillus jensenii. The loss of normal immunostimulatory flora in bacterial vaginosis is thus associated with a local deficiency of multiple innate immune factors, and this deficiency could predispose individuals to sexually transmitted diseases.     

Association of bacterial vaginosis with a history of second trimester miscarriage

The aim of this study was to determine whether bacterial vaginosis(BV) is associated with a history of recurrent pregnancy loss.A total of 500 consecutive patients attending the RecurrentMiscarriage Clinic were screened for the presence of BV. Inwomen who had had at least one late miscarriage BV was foundtwice as commonly (27/130; 21%) as in women who had had onlyearly losses (31/370; 8%) (P<0.001). The difference was evenlarger (26 versus 8%) if women who had had term pregnancieswere excluded. Moreover, BV was found three times more commonlyin Afro-Caribbean women [17 (29%) of 58] than in Caucasian women[36 (9%) of 379] and, in both groups of women, BV was diagnosedat least twice as frequently in those with a history of at leastone late miscarriage than in those who had experienced firsttrimester pregnancy losses only (P<0.001). The conditionoccurred twice as often among smokers than non-smokers and,in both groups, it was at least twice as common in women witha history of at least one late miscarriage as in those who hadhad early pregnancy losses only (P<0.001). However, the relationshipbetween BV and smoking was independent of ethnic origin. Womenwho douched with chloroxylenol were mostly Afro-Caribbean andhad BV more than twice as often as women who did not douche.     

Risk factors for bacterial vaginosis: results from a cross-sectional study having a sample of 53,652 women

The aim of this study was to estimate the risk factors of bacterial vaginosis (BV) among rural married women of childbearing age in Anhui Province of China. A cross-sectional study was conducted and the method of stratified cluster sampling was used to identify a sample of 53,652 married women aged 18–49 years. All women were asked to complete an interviewer-administered standardized questionnaire, covering sociodemographic characteristics, history of menstruation, marriage and procreation, sexual life, personal hygienic behaviors, and reproductive tract infections (RTIs) knowledge, followed by the gynecological examination and laboratory inspection. A total of 53,286 married women aged 18–49 years were included in this analysis. The prevalence of BV was 11.99 % (6,391/53,286). Risk factors for BV included the minority nationality, women’s lower education levels, husband’s elder age, over 35 days of menstrual cycle, less than 3 days of menstruation, dysmenorrhea, usage of an intrauterine device (IUD), lack of RTIs knowledge, higher frequency of washing genitals before having sex with husband and changing underwear, lower frequency of sexual intercourse per month, and suffering from other RTIs. The results suggest that BV can be affected by many factors among rural married women of reproductive age, so comprehensive, scheduled programs at healthcare educations should be provided for women in order to prevent BV.     

Inhibition of neutrophil shape change by an inhibitor of chemotaxis

Human mononuclear cells exposed to staphylococcal peptidoglycan in serum-free culture rapidly produce an inhibitor of neutrophil chemotaxis which we have previously described. We found that this inhibitor of chemotaxis has its most potent effect on the inhibition of neutrophil shape change from a spherical to a polarized configuration. In order to quantify this shape change inhibition, we developed an assay using flow cytometric techniques. Neutrophils exposed to a chemoattractant simultaneously change their shape and decrease their forward angle light scattering intensity (delta FLS) with a correlation coefficient of 0.886 (p less than 0.001). In 51 experiments, neutrophils pretreated with the inhibitor of chemotaxis decreased their FLS by only 6.8 +/- 1.3 channels, while neutrophils pretreated with medium or control culture supernatants decreased theirs by 26.4 +/- 1.9 and 20.5 +/- 3.0 channels respectively (p less than 0.001). The factor which causes inhibition of shape change was indistinguishable from the inhibitor of chemotaxis by physical properties and chromatography. We conclude that this inhibitor of chemotaxis may act by inhibiting a physiologic step at or before shape change.     

Diagnosis of bacterial vaginosis by direct gram stain of vaginal fluid.

To determine whether bacterial vaginosis (BV), also known as nonspecific vaginitis, could be diagnosed by evaluating a Gram stain of vaginal fluid, we examined samples from 60 women of whom 25 had clinical evidence of BV and 35 had candidal vaginitis or normal examinations. An inverse relationship between the quantity of the Lactobacillus morphotype (large gram-positive rods) and of the Gardnerella morphotype (small gram-variable rods) was noted on Gram stain (P less than 0.001). When Gram stain showed a predominance (3 to 4+) of the Lactobacillus morphotype with or without the Gardnerella morphotype, it was interpreted as normal. When Gram stain showed mixed flora consisting of gram-positive, gram-negative, or gram-variable bacteria and the Lactobacillus morphotype was decreased or absent (0 to 2+), the Gram stain was interpreted as consistent with BV. Gram stain was consistent with BV in 25 of 25 women given a clinical diagnosis of BV and in none of 35 women with candidal vaginitis or normal examinations. Duplicate slides prepared from 20 additional specimens of vaginal fluid were stained by two methods and examined by three evaluators. Interevaluator interpretations and intraevaluator interpretations of duplicate slides were in agreement with one another and with the clinical diagnosis greater than or equal to 90% of the time. We concluded that a microscopically detectable change in vaginal microflora from the Lactobacillus morphotype, with or without the Gardnerella morphotype (normal), to a mixed flora with few or no Lactobacillus morphotypes (BV) can be used in the diagnosis of BV.     

Antibiotic resistance of Gardnerella vaginalis in recurrent bacterial vaginosis

Fifty strains of Gardnerella vaginalis isolated from 321 high vaginal swabs over a period of five months were tested for their antibiotic sensitivity. Sixty eight per cent of all isolates were resistant to metronidazole while 76% were sensitive to clindamycin. All the strains isolated from cases with recurrence of infection were resistant to metronidazole. Clindamycin therapy has a better clinical efficacy than metronidazole in cases of recurrent bacterial vaginosis.     

Mobiluncus species in bacterial vaginosis: aspects of pathogenesis

Mobiluncus is an anaerobic motile rod associated with bacterial vaginosis. In this work, luminol-enhanced chemiluminescence was used to study the ability of Mobiluncus spp. from the vaginas of women with bacterial vaginosis to induce, in the presence of normal adult serum, oxidative metabolism of polymorphonuclear leukocytes, which is an indirect measure of phagocytic activity. M. curtisii induced a significantly (p less than 0.05) lower response than M. mulieris, which indicates that M. curtisii escapes phagocytosis more easily. Indirect immunofluorescence assays showed IgG antibodies to M. curtisii at significantly (p less than 0.01) higher titres than to M. mulieris in women with bacterial vaginosis. The titres were higher in patients with bacterial vaginosis than in women without vaginosis and healthy men. No antibodies to Mobiluncus spp. of secretory IgA type were found in vaginal washings. These results indicate that M. curtisii is a more virulent species than M. mulieris, and agree with reports of M. curtisii found in postoperative and extragenital infections.     

Reliability of diagnosing bacterial vaginosis is improved by a standardized method of gram stain interpretation.

The purpose of the study was to examine intercenter variability in the interpretation of Gram-stained vaginal smears from pregnant women. The intercenter reliability of individual morphotypes identified on the vaginal smear was evaluated by comparing them with those obtained at a standard center. A new scoring system that uses the most reliable morphotypes from the vaginal smear was proposed for diagnosing bacterial vaginosis. This scoring system was compared with the Spiegel criteria for diagnosing bacterial vaginosis. The scoring system (0 to 10) was described as a weighted combination of the following morphotypes: lactobacilli, Gardnerella vaginalis or bacteroides (small gram-variable rods or gram-negative rods), and curved gram-variable rods. By using the Spearman rank correlation to determine intercenter variability, gram-positive cocci had poor agreement (0.23); lactobacilli (0.65), G. vaginalis (0.69), and bacteroides (0.57) had moderate agreement; and small (0.74) and curved (0.85) gram-variable rods had good agreement. The reliability of the 0 to 10 scoring system was maximized by not using gram-positive cocci, combining G. vaginalis and bacteroides morphotypes, and weighting more heavily curved gram-variable rods. For comparison with the Spiegel criteria, a score of 7 or higher was considered indicative of bacterial vaginosis. The standardized score had improved intercenter reliability (r = 0.82) compared with the Spiegel criteria (r = 0.61). The standardized score also facilitates future research concerning bacterial vaginosis because it provides gradations of the disturbance of vaginal flora which may be associated with different levels of risk for pregnancy complications.