POS0249 THE EFFECT OF NASAL STAPHYLOCOCCUS AUREUS COLONIZATION ON DISEASE ACTIVITY AND THE EFFECT OF ANTIBIOTIC TREATMENT IN PATIENTS WITH ANCA ASSOCIATED VASCULITIS; A RETROSPECTIVE COHORT STUDY

Background:

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) is a necrotizing vasculitis, predominantly affecting small or medium vessels with few or no immune deposits. Ear, nose and throat (ENT) involvement in AAV is frequently present. AAV has a relapsing-remitting disease course. A factor that has been associated with induction of relapses is nasal Staphylococcus aureus (S. aureus) colonization. This alleged association between nasal colonization and induction of relapses has resulted in the use of antibiotics. However, the effect of antibiotic treatment on disease activity remains controversial. Some studies showed a beneficial effect of antibiotic treatment whereas other studies found no effect of antibiotic treatment on disease activity.

Objectives:

The aim of this study was to identify the role of nasal S. aureus colonization and the effect of systemic or local antibiotic treatment on disease activity in patients with AAV.

Methods:

Clinical, laboratory and histological data from all AAV patients with ENT involvement, diagnosed in two medical centers between 1981 and 2020, were retrospectively collected. Nasal S. aureus colonization was defined as at least one positive nasal swab during follow-up. Data on systemic (cotrimoxazole and azithromycin) and local antibiotics (mupirocin) use was collected. Disease activity was divided into systemic and local disease activity. Systemic disease activity consisted of history of relapses, relapse number per patient years and Birmingham vasculitis activity score version 3 (BVAS3) at last visit. Local disease activity included history of ENT relapses, development of saddle nose deformity or subglottic stenosis during follow-up.

Results:

Two-hundred and thirteen patients were included in the analysis. Median follow-up time was 8 (IQR 3 -17) years. S. aureus colonization was tested in 100 (46.9%) cases of which 44 patients tested positive. Only one patient developed a subglottic stenosis, and 13 patients developed a saddle nose deformity during follow-up. Systemic and local disease activity at baseline and at last visit were comparable between patients with and without and S. aureus colonization. Regression analysis showed no difference in relapse number per patient year between AAV patients colonized with S. aureus versus non-colonized patients (RR 2.03; 95%CI, 0.97 – 4.26, p=0.06). This also accounted for local ENT relapses (OR 0.134; 95%CI 0.06-1.47, p=0.14) and saddle nose deformity (OR 0.61; 95%CI 0.04-10.68, p=0.74). Twenty-eight (13.1%) S. aureus positive patients received antibiotics aimed at eradication of S. aureus. Twenty-two (10.3%) received cotrimoxazole, 2 (0.9%) received azithromycin and 17 (8.0%) patients received mupirocin ointment. No significant difference was found between the treated versus non-treated group with regard to systemic and local disease activity.

Conclusion:

Nasal S. aureus colonization does not influence systemic or local disease activity. Antibiotic eradication treatment did not modify disease activity in this study.

Table 1.

Effect of AB treatment on disease activity of 40 AAV patients with ENT involvement and S. aureus colonization

Disease activityAntibiotic treatmentP-valueYes (n=28)No (n=12)Systemic symptomsHistory of one or more relapses, n (%)18 (47.4%)4 (10.5%)0.635Relapse number per patient years, median (IQR) *0.11 (0-0.18)0.17 (0.02 – 0.26)0.346BVAS3 last visit, median (IQR)1 (0-4)1 (0-4)0.932Local symptomsHistory of one or more ENT relapses, n(%) *9 (33.3%)3 (11.1%)0.438Development of saddle nose deformity during follow-up, n (%) *4 (12.1%)0 (0%)0.367

Values are median (interquartile range IQR) or n (%). BVAS3: Birmingham Vasculitis Activity Score version 3; ANCA: Anti-Neutrophilic Cytoplasmic Autoantibody; AAV: ANCA associated vasculitis; ENT: ear, nose and throat. * More than 10% missings in analysis. For an overview of the number of included patients per analysis, see supplementary table B.

Disclosure of Interests:

None declared

Relationship between enteric pathogens and acute gastroenteritis disease severity: a prospective cohort study

OBJECTIVES

To evaluate the relationship between individual bacterial and viral pathogens and disease severity.

METHODS

Children <18 years with three or more episodes of vomiting and/or diarrhoea were enrolled in two Canadian paediatric emergency departments between December 2014 and August 2016. Specimens were analysed employing molecular panels, and outcome data were collected 14 days after enrolment. The primary outcome was severe disease over the entire illness (symptom onset until 14-day follow-up), quantified employing the Modified Vesikari Scale (MVS) score. The score was additionally analysed in two other time periods: index (symptom onset until enrolment) and follow-up (enrolment until 14-day follow-up).

RESULTS

Median participant age was 20.7 (IQR: 11.3, 44.2) months; 47.4% (518/1093) and 73.4% (802/1093) of participants had index and total MVS scores ≥11, respectively. The most commonly identified pathogens were rotavirus (289/1093; 26.4%) and norovirus (258/1093; 23.6%). In multivariable analysis, severe disease over the entire illness was associated with rotavirus (OR = 9.60; 95%CI: 5.69, 16.19), Salmonella (OR = 6.61; 95%CI: 1.50, 29.17), adenovirus (OR = 2.53; 95%CI: 1.62, 3.97), and norovirus (OR = 1.43; 95%CI: 1.01, 2.01). Pathogens associated with severe disease at the index visit were: rotavirus only (OR = 6.13; 95%CI: 4.29, 8.75), Salmonella (OR = 4.59; 95%CI: 1.71, 12.29), adenovirus only (OR = 2.06; 95%CI: 1.41, 3.00), rotavirus plus adenovirus (OR = 3.15; 95%CI: 1.35, 7.37), and norovirus (OR = 0.68; 95%CI: 0.49, 0.94). During the follow-up period, rotavirus (OR = 2.21; 95%CI: 1.50, 3.25) and adenovirus (OR = 2.10; 95%CI: 1.39, 3.18) were associated with severe disease.

CONCLUSIONS

In children presenting for emergency department care with acute gastroenteritis, pathogens identified were predominantly viruses, and several of which were associated with severe disease. Salmonella was the sole bacterium independently associated with severe disease.

No impact of early real-time PCR screening for respiratory viruses on length of stay and use of antibiotics in elderly patients hospitalized with symptoms of a respiratory tract infection in a single center in Norway

We tested the hypothesis that the results of real-time polymerase chain reaction (PCR) analyses for respiratory viruses would reduce antibiotic treatment and length of stay in elderly patients hospitalized with respiratory infections. Within 24 h of hospital admission, a total of 922 patients aged ≥60 years were interviewed for symptoms of ongoing respiratory tract infection. Symptomatic patients were swabbed for oropharyngeal/nasopharyngeal presence of viral pathogens immediately by members of the study group. During a 2-month period, non-symptomatic volunteers among interviewed patients were swabbed as well (controls). Oropharyngeal/nasopharyngeal swabs were analyzed with real-time PCR for nine common respiratory viruses. A total of 147 out of 173 symptomatic patients and 56 non-symptomatic patients (controls) agreed to participate in the study. The patients were allocated to three cohorts: (1) symptomatic and PCR-positive (S/PCR+), (2) symptomatic and PCR-negative (S/PCR−), or (3) non-symptomatic and PCR-negative (control). There were no non-symptomatic patients with a positive PCR result. A non-significant difference in the frequency of empiric antibiotic administration was found when comparing the S/PCR+ to the S/PCR− cohort; 16/19 (84 %) vs. 99/128 (77 %) (χ² = 0.49). Antibiotic treatment was withdrawn in only two patients in the S/PCR+ cohort after receiving a positive viral diagnosis. The length of stay did not significantly differ between the S/PCR+ and the S/PCR− groups. We conclude that, at least in our general hospital setting, access to early viral diagnosis by real-time PCR had little impact on the antimicrobial treatment or length of hospitalization of elderly patients.

Neutralization of LPS or blockage of TLR4 signaling prevents stress-triggered fetal loss in murine pregnancy

Maternal stress can cause loss of both histocompatible (syngeneic) and histoincompatible (semiallogeneic) embryos in pregnant mice. Stress increases abortogenic Th1 cytokines and reduces levels of anti-abortogenic Th2 cytokines, progesterone levels, and T regulatory cell activity. While physiological levels of interferon-γ promote vascular remodeling at the feto-maternal interface, an overshooting Th1 cytokine response requires a Toll-like receptor (TLR)-mediated "danger signal" such as lipopolysaccharide (LPS). Interestingly, stress can enhance permeability of mucosal membranes to entry of bacterial products and promote transmucosal migration of commensal bacteria. We hypothesized that bacterial component such as LPS may provide the danger signal through which stress triggers maternal immune activation, subsequently resulting in fetal rejection. Blocking the TLR4 receptor for LPS or neutralization of LPS using bactericidal permeability increasing protein abrogate fetal loss due to sonic stress challenge in DBA/2J-mated CBA/J mice. These treatments prevented stress-triggered immune responses in the decidua, upregulated Treg cells, and reduced the frequency of mature dendritic cells in uterine-draining lymph nodes but not in the uterus. Interestingly, anti-TLR4 treatment only partly ameliorated stress-induced endocrine responses, such as increased hypothalamic corticotropin releasing hormone and vasopressin mRNA expression but not decrease of serum progesterone. Galectin-1 knock-out mice were more susceptible to stress-triggered complete implantation failure rather than fetal loss, which was also abolished by LPS neutralization. Insights provided in this paper shed new light on the mechanisms by which stress affects pregnancy outcome and introduce microbial-derived LPS as a mediator within the cascade of stress-triggered immune and endocrine events during pregnancy.

Swabbing for respiratory viral infections in older patients: a comparison of rayon and nylon flocked swabs

The purpose of this study was to compare the sampling efficacy of rayon swabs and nylon flocked swabs, and of oropharyngeal and nasopharyngeal specimens for the detection of respiratory viruses in elderly patients. Samples were obtained from patients 60 years of age or above who were newly admitted to Sorlandet Hospital Arendal, Norway. The patients were interviewed for current symptoms of a respiratory tract infection. Using rayon swabs and nylon flocked swabs, comparable sets of mucosal samples were harvested from the nasopharynx and the oropharynx. The samples were analysed using real-time polymerase chain reaction (PCR) methods. A total of 223 patients (mean age 74.9 years, standard deviation [SD] 9.0 years) were swabbed and a virus was recovered from 11% of the symptomatic patients. Regardless of the sampling site, a calculated 4.8 times higher viral load (95% confidence interval [CI] 1.3-17, p = 0.017) was obtained using the nylon flocked swabs as compared to the rayon swabs. Also, regardless of the type of swab, a calculated 19 times higher viral load was found in the samples from the nasopharynx as compared to the oropharynx (95% CI 5.4-67.4, p < 0.001). When swabbing for respiratory viruses in elderly patients, nasopharyngeal rather than oropharyngeal samples should be obtained. Nylon flocked swabs appear to be more efficient than rayon swabs.

Transthoracic fine-needle aspiration in the aetiological diagnosis of community-acquired pneumonia

Clin Microbiol Infect 2010; 16: 909–911

Abstract

To investigate the safety and practicability of conducting transthoracic fine‐needle aspiration (TFNA) in a general hospital setting, we applied the TFNA procedure to 20 patients hospitalized with community‐acquired pneumonia (CAP) within 36 h of admission. Also, a preliminary assessment was made of the potential value of adding TFNA to conventional methods of diagnostic microbiology. TFNA was easy to perform and caused little discomfort, and no serious adverse events were observed. In spite of ongoing antimicrobial treatment, a likely aetiological diagnosis was established for 14 of 20 (70%) of the patients. TFNA may provide important additional information on the aetiology of CAP.

Stress-induced neurogenic inflammation in murine skin skews dendritic cells towards maturation and migration: key role of intercellular adhesion molecule-1/leukocyte function-associated antigen interactions

The skin continuously serves as a biosensor of multiple exogenous stressors and integrates the resulting responses with an individual's central and peripheral endogenous response systems to perceived stress; it also acts to protect against external challenges such as wounding and infection. We have previously shown in mice that stress induces nerve growth factor- and substance P-dependent neurogenic inflammation, which includes the prominent clustering of MHC class II(+) cells. Because the contribution of dendritic cells (DCs) in response to stress is not well understood, we examined the role of DCs in neurogenic inflammation in murine skin using a well-established murine stress model. We show that sound stress increases the number of intradermal langerin(+) and CD11c(+) DCs and induces DC maturation, as indicated by the up-regulated expression of CD11c, MHC class II, and intercellular adhesion molecule-1 (ICAM-1). Blocking of ICAM-1/leukocyte function-associated antigen-1 interactions significantly abrogated the stress-induced numeric increase, maturation, and migration of dermal DCs in vivo and also reduced stress-induced keratinocyte apoptosis and endothelial cell expression of ICAM-1. In conclusion, stress exposure causes a state of immune alertness in the skin. Such adaptation processes may ensure protection from possible infections on wounding by stressors, such as attack by predators. However, present-day stressors have changed and such adaptations appear redundant and may overrun skin homeostasis by inducing immune dermatoses.

Probing the effects of stress mediators on the human hair follicle: substance P holds central position

Stress alters murine hair growth, depending on substance P-mediated neurogenic inflammation and nerve growth factor (NGF), a key modulator of hair growth termination (catagen induction). Whether this is of any relevance in human hair follicles (HFs) is completely unclear. Therefore, we have investigated the effects of substance P, the central cutaneous prototypic stress-associated neuropeptide, on normal, growing human scalp HFs in organ culture. We show that these prominently expressed substance P receptor (NK1) at the gene and protein level. Organ-cultured HFs responded to substance P by premature catagen development, down-regulation of NK1, and up-regulation of neutral endopeptidase (degrades substance P). This was accompanied by mast cell degranulation in the HF connective tissue sheath, indicating neurogenic inflammation. Substance P down-regulated immunoreactivity for the growth-promoting NGF receptor (TrkA), whereas it up-regulated NGF and its apoptosis- and catagen-promoting receptor (p75NTR). In addition, MHC class I and beta2-microglobulin immunoreactivity were up-regulated and detected ectopically, indicating collapse of the HF immune privilege. In conclusion, we present a simplistic, but instructive, organ culture assay to demonstrate sensitivity of the human HF to key skin stress mediators. The data obtained therewith allow one to sketch the first evidence-based biological explanation for how stress may trigger or aggravate telogen effluvium and alopecia areata.

Further exploring the brain-skin connection: stress worsens dermatitis via substance P-dependent neurogenic inflammation in mice

A neurogenic component in atopy and allergy is evident and potentially of great pathogenic relevance. Stress was recently shown to activate elements of this component and is vividly discussed as a cause of exacerbation. However, to date, scientific proof of stress-induced neuronal plasticity and neuro-immune interaction in atopy or allergy remains lacking. Here we show early evidence that exposure to sound stress and atopic dermatitis-like allergic dermatitis (AD) equipotently raise the number of cutaneous nerve fibers containing the prototypic stress neuropeptide substance P (SP) in mice. Stress increases AD readout parameters by at least 30% (eosinophil infiltration, vascular cell adhesion molecule-positive blood vessels, epidermal thickness). This dramatic pathologic exacerbation is associated with increased neurogenic inflammation (degranulated mast cells; interstitial neuropeptidergic dense core granules, mast cell apoptosis, endothelial gaping). Key features of AD exacerbation could not be induced in mice lacking the neurokinin-1 SP receptor (NK1). Interestingly, stress had no significant additional effect on CD4+ cell number, but shifted the cytokine profile toward TH2 in skin. Thus, we conclude that stress primarily exacerbates AD via SP-dependent cutaneous neurogenic inflammation and subsequent local cytokine shifting and should be considered as a therapeutic target, while it offers a convincing pathogenic explanation to affected patients and their frustrated physicians alike.

Stress induces substance P in vagal sensory neurons innervating the mouse airways

BACKGROUND

Tachykinins-like substance P (SP) have been shown to play an important role in initiating and perpetuating airway inflammation. Furthermore, they are supposed to be released into tissues in response to stress.

OBJECTIVE

The aim of this study was to investigate the effects of stress alone or in combination with allergic airway inflammation on SP expression in sensory neurons innervating the mouse airways.

METHODS

Balb/c mice were systemically sensitized to ovalbumin (OVA), followed by allergen aerosol exposure, and compared with non-sensitized controls. Additionally, OVA-sensitized and -challenged and non-sensitized mice were exposed to sound stress. SP expression in airway-specific and overall vagal sensory neurons of the jugular and nodose ganglion complex was analysed using retrograde neuronal tracing in combination with immunohistochemistry. Preprotachykinin A (PPT-A) mRNA, the precursor for SP, was quantified in lung tissue by real-time PCR. Bronchoalveolar lavage (BAL) fluid was obtained, and cell numbers and differentiation were determined.

RESULTS

Stress and/or allergic airway inflammation significantly increased SP expression in retrograde-labelled vagal sensory neurons from the mouse lower airways compared with controls [stress: 15.7+/-0.8% (% of retrograde-labelled neurons, mean+/-SEM); allergen: 17.9+/-0.4%; allergen/stress: 13.1+/-0.7% vs. controls: 6.3+/-0.3%]. Similarly, SP expression increased in overall vagal sensory neurons identified by the neuronal marker protein gene product (PGP) 9.5 [stress: 9.3+/-0.6% (% of PGP 9.5-positive neurons, means+/-SEM); allergen: 12.5+/-0.4%; allergen/stress: 10.2+/-0.4% vs. controls: 5.1+/-0.3%]. Furthermore, stress significantly increased PPT-A mRNA expression in lung tissue from OVA-sensitized and -challenged animals, and immune cells were identified as an additional source of SP in the lung by immunohistochemistry. Associated with enhanced neuronal SP expression, a significantly higher number of leucocytes were found in the BAL following allergen exposure. Further, stress significantly increased allergen-induced airway inflammation identified by increased leucocyte numbers in BAL fluids.

CONCLUSION

The central event of sound stress leads to the stimulation of SP expression in airway-specific neurons. However, in sensitized stressed mice an additional local source of SP (probably inflammatory cells) might enhance allergic airway inflammation.

Evaluation of the pharmacokinetic interaction between fluvastatin XL and cyclosporine in renal transplant recipients

OBJECTIVE

To assess the pharmacokinetic interaction between cyclosporine and extended-release fluvastatin (fluvastatin XL), 80 mg for 7 days, in stable renal transplant recipients.

METHODS

This was a single-center, open-label study. 17 renal transplant recipients received their standard cyclosporine therapy (Days 1 - 9) plus a once-daily single oral dose of fluvastatin XL, 80 mg (Days 2 - 8). Blood samples were collected and cyclosporine (whole blood) and fluvastatin (plasma) concentrations determined by radioimmunoassay and HPLC fluorescence detection, respectively. Pharmacokinetic parameters were calculated using non-compartment analysis and fluvastatin results were compared with historical controls.

RESULTS

Treatment with fluvastatin XL, 80 mg for 7 days, had no significant effect on either the AUC0-12 (3,644 ng x h/ml in the absence of fluvastatin vs. 3,534 ng x h/ml in the presence of fluvastatin) or the Cmax of cyclosporine (983 ng/ml in the absence of fluvastatin vs. 945 ng/ml in the presence of fluvastatin). Co-administration of fluvastatin XL also had no effect on the tmax, t1/2 or apparent clearance (CL/F) of cyclosporine in renal transplant patients. The AUC and Cmax for fluvastatin XL in the presence of cyclosporine (AUC0-24 1,192 ng. x h/ml, Cmax 271 ng/ml) were approximately 2-fold higher compared with historical data for fluvastatin XL alone in healthy volunteers (AUC0-24 630 ng x h/ml, Cmax 102 ng/ml) but lower than the historical data for fluvastatin IR, 40 mg b.i.d. alone in healthy volunteers (AUC0-24 1,340 ng x h/ml, Cmax 443 ng/ml). Tmax, t1/2 and trough levels of fluvastatin in the presence of cyclosporine were also similar to the historical controls. Concomitant administration of cyclosporine and fluvastatin XL was well tolerated by renal transplant recipients.

CONCLUSIONS

Fluvastatin XL, 80 mg, and cyclosporine do not show clinically relevant pharmacokinetic interactions.

Stress and substance P but not the substance P-metabolite SP5-11 trigger murine abortion by augmenting TNF-alpha levels at the feto-maternal interface

In a well-established murine abortion model, stress is thought to trigger fetal rejection by inducing a proinflammatory immune response via substance P (SP), being tumour necrosis factor (TNF)-alpha-producing CD8+ T cells involved. Interestingly, the SP metabolite SP5-11 also binds to SP receptors and mediates SP-like effects on immune cells at sites of inflammation. No data were available regarding the effects of SP5-11 on pregnancy outcome in the CBA/J x DBA/2J abortion-prone combination. We investigated the influence of SP5-11 in contrast to stress or SP on the abortion rate and the cytokine production by lymphocytes as well as on the levels of CD8+ T cells. Stress and SP boosted the abortion rate and increased the percentage of type 1 [TNF-alpha, interferon-gamma, interleukin (IL)-12] and type 2 (IL-4 and IL-10) cytokine-producing lymphocytes in blood and decidua, predominantly CD8+ T cells. Interestingly, SP5-11 did not significantly affect the abortion rate or cytokine production in the decidua, while increasing the Th1 and Th2 cytokine production systemically. Our data suggest that stress and SP induce abortion by augmenting the local levels of TNF-alpha, which seems therefore to be a potent trigger of miscarriage. On the contrary, the SP metabolite SP5-11 only affects the systemic cytokine production without boosting the abortion rate in this experimental model.

Intercellular adhesion molecule-1/LFA-1 cross talk is a proximate mediator capable of disrupting immune integration and tolerance mechanism at the feto-maternal interface in murine pregnancies

Our understanding why a woman's immune system does not reject her histoincompatible fetus is still very limited. Distinct insights into the mechanisms involved in pregnancy maintenance may help us to prevent pregnancy complications, e.g., miscarriages or pre-eclampsia. Immune integration and tolerance at the feto-maternal interface appear to be indispensable for successful pregnancy maintenance. Little is known about the cross talk between ICAM-1, expressed on epithelium, endothelium, and APC, and its ligand, LFA-1, at the feto-maternal interface. However, based on the role of ICAM-1/LFA-1 in allograft acceptance or rejection upon transplantation, adhesion molecules are likely to interfere with successful pregnancy outcome. In this study, we tested the hypothesis that ICAM-1/LFA-1 pathways may be involved in pregnancy rejection in murine models. By blocking ICAM-1/LFA-1-mediated intercellular adhesion events, we show that fetal immune acceptance is restored in challenged pregnancies (e.g., upon exposure to sound stress), and adoptive transfer of LFA-1 cells into pregnant mice induces rejection only in abortion-prone mouse models. ICAM-1/LFA-1 cross talk leads to increased recruitment of proinflammatory cells to the implantation site, promotes dendritic cell maturation in the decidua, and subsequently induces additional local Th1 polarization via mature dendritic cells. Furthermore, our observations clearly point out that mechanisms of fetal tolerance, e.g., indoleamine 2,3-dioxygenase expression, presence of CD4+CD25bright regulatory T cells, and synthesis of asymmetric Abs, are ICAM-1/LFA-1 dependent. Hence, our data shed light on a hierarchical network of immune integration at the feto-maternal interface, in which ICAM-1/LFA-1 cross talk is clearly a proximate mediator capable of disrupting successful pregnancy maintenance.

Uptake of vitamin A in macrophages from physiologic transport proteins: role of retinol-binding protein and chylomicron remnants

Vitamin A plays an important role in reducing infectious disease morbidity and mortality by enhancing immunity, an effect that is partly mediated by macrophages. Thus, knowing how these cells take up vitamin A is important. The results in the present study demonstrate that J774 macrophages efficiently take up chylomicron remnant retinyl esters and retinol-binding protein (retinol-RBP) bound retinol by specific and saturable mechanisms. The binding of (125)I-RBP to plasma membrane vesicles demonstrated that the macrophage receptor had a similar binding affinity, as was discovered previously for other cells. The B(max) for the macrophages was smaller than the values reported for placenta, bone marrow, and kidney, but larger than that reported for liver. The J774 cells also bound and took up [(3)H]retinol-RBP. Approximately 50 to 60% of the uptake may compete with excess unlabeled retinol-RBP and approximately 30 to 40% with excess transtyrethin. Following the uptake of [(3)H]retinol-RBP, an extensive esterification occurred: After 5 hours of incubation, 77.8 +/- 3.9% (SD; n = 3) of the cellular radioactivity was recovered as retinyl esters. The J774 cells also demonstrated saturable binding of chylomicron remnant [(3)H]retinyl esters, and a continuous uptake at 37 degrees C followed by an extensive hydrolysis of the retinyl esters. Binding could be inhibited by approximately 50% by excess unlabeled low density lipoprotein (LDL). In addition, lipoprotein lipase increased the binding of chylomicron remnant [(3)H]retinyl esters by approximately 30% and the uptake of chylomicron remnant [(3)H]retinyl ester by more than 300%. Furthermore, because sodium chlorate reduced binding with 40% and uptake with 55%, the results suggest that proteoglycans are involved in the uptake. Thus, the results suggest that both LDL receptor and LDL-related protein are involved in the uptake of chylomicron remnant [(3)H]retinyl ester in macrophages.

Neurogenic inflammation in stress-induced termination of murine hair growth is promoted by nerve growth factor

Recently, we have revealed the existence of a "brain-hair follicle axis" in murine skin and have identified the neuropeptide substance P (SP) as a key mediator of stress-induced hair growth inhibition in vivo. Published evidence suggests that increased numbers of SP-immunoreactive sensory fibers, as seen in the dermis of stressed mice in anagen-catagen transition, are a result of transient high levels of nerve growth factor (NGF). Thus, we now aimed at dissecting the role of NGF in stress-triggered hair growth termination in our murine model. By real time PCR and immunohistochemistry, stress-exposed mice showed an up-regulation of NGF and its low-affinity receptor p75NTR; the NGF high-affinity receptor TrkA was moderately down-regulated. On neutralization of NGF, premature onset of catagen, apoptosis, and increased number/activation of perifollicular mast cells and antigen-presenting cells, which reflects the skin response to stress, was significantly abrogated. Stress or subcutaneous injection of recombinant NGF (to mimic stress) resulted in an increased percentage of SP(+) neurons in dorsal root ganglia, as measured by retrograde tracing. Taken together, these data suggest that NGF is a central element in the perifollicular neurogenic inflammation that develops during the murine skin response to stress and antagonizing NGF may be a promising therapeutic approach to counter the negative effect of stress on hair growth.

Topical minoxidil counteracts stress-induced hair growth inhibition in mice

Stress has long been suspected as a possible cause of hair loss in various species, even though convincing experimental evidence has not been available. Recently, we have shown in a murine model that sonic stress alters hair growth and cycling in vivo, and have postulated the existence of a 'brain-hair follicle axis' (BHA). In order to study whether a clinically available and widely used topically active hair growth stimulator mitigates stress-triggered hair growth inhibition in this stress model, we have applied a 5% minoxidil solution. Female CBA/J mice were depilated and randomized in to two groups: control (n = 20) and sonic stress (n = 20). These groups were further divided and either treated daily with 5% minoxidil solution or vehicle alone. The stress group was exposed to sonic stress for 24 h starting 14 days after anagen induction by depilation. All mice were sacrificed 16 days after the depilation and assessed by quantitative histomorphometry. Sonic stress significantly increased the number of hair follicles with apoptotic cells and inhibited intrafollicular keratinocyte proliferation. In addition, the number of clusters of perifollicular MHC class II+ cells and degranulated perifollicular mast cells was significantly enhanced in the stressed mice. In accordance with previous findings, all stressed mice showed an advanced hair cycle progression towards catagen. All of these stress-induced hair growth inhibitory changes along the BHA were down-regulated by topical minoxidil application. This encourages one to explore clinically whether topical minoxidil is a safe and effective pharmacologic tool for the management of stress-associated telogen effluvium in humans.

Heme oxygenases in pregnancy II: HO-2 is downregulated in human pathologic pregnancies

PROBLEM

We previously reported a diminished expression of the heme-degrading enzymes heme oxygenases (HO)-1 and HO-2 in decidua and placenta from mice undergoing Th1-mediated abortion, strongly indicating the protective effect of HO in murine pregnancy maintenance. Here we investigated whether the expression of HO-1 and HO-2 is also reduced at the feto-maternal interface of pathologic human pregnancies.

METHOD OF STUDY

Immunohistochemistry was used to detect HOs expression in placental and decidual first-trimester tissue from patients with: spontaneous abortion (n = 14), choriocarcinoma (n = 14), hydatidiform mole (H-mole) (n = 12), compared with normally progressing pregnancies (n = 15). Further, we investigated early third-trimester decidual and placental tissue from patients with pre-eclampsia (n = 13) compared with fetal growth retardation (n = 14) as age-matched controls.

RESULTS

In first trimester tissue, we observed a significant reduction of HO-2 expression in invasive trophoblast cells, endothelial cells, and syncytiotrophoblasts in samples from patients with spontaneous abortion compared with normal pregnancy. H-mole samples showed a diminished expression of HO-2 in invasive trophoblast cells and endothelial cells in comparison with NP, whereas choriocarcinoma samples showed no significant differences compared with the control. In third trimester tissue, HO-2 was also reduced in syncytiotrophoblasts and invasive trophoblast cells from pre-eclampsia compared with samples from fetal growth retardation. HO-1 expression was diminished in all pathologies investigated; however, the differences did not reach levels of significance.

CONCLUSIONS

Our data indicate that HOs play a crucial role in pregnancy and low expression of HO-2, as observed in pathologic pregnancies, may lead to enhanced levels of free heme at the feto-maternal interface, with subsequent upregulation of adhesion molecules, allowing enhanced inflammatory cells migration to the feto-maternal interface.

Th1 cytokines and the prothrombinase fgl2 in stress-triggered and inflammatory abortion

PROBLEM

The immune system contributes to the outcome of pregnancy by complex immunological interactions. Cytokines especially influence the immune milieu pro or contra pregnancy. T helper 1 (Th1) cytokines [tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma)] cause inflammation and together are thought to threaten the maintenance of pregnancy. It has been proposed that increased levels of these Th1 cytokines activate coagulation via up-regulating the novel prothrombinase, fgl2. This study further investigates the Th1 cytokine up-regulation of fgl2 expression in a pathophysiological, stress induced abortion model, and an inflammatory, interleukin-12 (IL-12) triggered abortion model.

METHOD

The DBA/2J-mated CBA/J female mice were exposed to sonic sound stress or were injected with IL-12 during early gestation. On day 13.5 of pregnancy the uteri were removed and the resorption rate was calculated. We evaluated TNF-alpha, IFN-gamma, fgl2 as well as IL-12 messenger RNA (mRNA) expression in decidual samples of all mice by quantitative, real-time polymerase chain reaction (PCR).

RESULTS

A similar resorption rate of 24% was detected in stressed mice, as well as in IL-12 injected mice compared with approximately 11% in non-stressed, non-injected control mice. In stressed mice compared with controls, we observed on day 13.5 up-regulated TNF-alpha, unchanged IFN-gamma down-regulated fgl2, and a slightly increased levels of IL-12. In the IL-12 triggered abortion model, we observed up-regulated levels of TNF-alpha, IFN-gamma and fgl2.

CONCLUSION

These novel data suggest two distinct cytokine patterns leading to similar abortion rates. A physiological cascade associated with up-regulation of TNF-alpha, and an IL-12-triggered cascade characterized by persistent up-regulation of TNF-alpha and IFN-gamma as well as a persistent increase in fgl2.

Stress inhibits hair growth in mice by induction of premature catagen development and deleterious perifollicular inflammatory events via neuropeptide substance P-dependent pathways

It has been much disputed whether or not stress can cause hair loss (telogen effluvium) in a clinically relevant manner. Despite the paramount psychosocial importance of hair in human society, this central, yet enigmatic and controversial problem of clinically applied stress research has not been systematically studied in appropriate animal models. We now show that psychoemotional stress indeed alters actual hair follicle (HF) cycling in vivo, ie, prematurely terminates the normal duration of active hair growth (anagen) in mice. Further, inflammatory events deleterious to the HF are present in the HF environment of stressed mice (perifollicular macrophage cluster, excessive mast cell activation). This provides the first solid pathophysiological mechanism for how stress may actually cause telogen effluvium, ie, by hair cycle manipulation and neuroimmunological events that combine to terminate anagen. Furthermore, we show that most of these hair growth-inhibitory effects of stress can be reproduced by the proteotypic stress-related neuropeptide substance P in nonstressed mice, and can be counteracted effectively by co-administration of a specific substance P receptor antagonist in stressed mice. This offers the first convincing rationale how stress-induced hair loss in men may be pharmacologically managed effectively.

Heme oxygenase is downregulated in stress-triggered and interleukin-12-mediated murine abortion

Heme oxygenases (HOs) are responsible for heme degradation. Besides their enzymatic activities, HOs are involved in tissue protection. Failing upregulation of HOs has been linked to increased necrosis in inflammatory tissues. Interestingly, previously published data indicated that mice exposed to sonic stress during early gestation show an augmented production of decidual inflammatory T-helper 1 (Th1) cytokines, thus resulting in increased abortion rate. No data linked the Th1-inducer interleukin (IL)-12 with the event of abortion. As little is known about the role of HO in pregnancy maintenance, we evaluated the expression of decidual and placental HO-1 and HO-2 in the abortion-prone murine mating combination CBA/J x DBA/2 J with (1) CBA/J female control mice, (2) CBA/J mice exposed to stress during early gestation and (3) CBA/J females injected with recombinant IL-12. Decidual and placental HOs protein expression was analysed by immunohistochemistry and mRNA levels by real time polymerase chain reaction (PCR). As expected, an increased abortion rate was present in mice exposed to stress compared with the control. IL-12 injections also boosted the abortion rate compared with control mice, mimicking the effect of stress. HOs' proteins could be detected in placenta and decidua. Real time PCR revealed lower levels of HO-1 and HO-2 mRNA in stress-triggered and IL-12-injected mice. We conclude that increased Th1-cytokine levels during murine pregnancy may result in low expression of HO-1 and HO-2, thus leading to placental necrosis and foetal rejection.

Upregulation of decidual P-selectin expression is associated with an increased number of Th1 cell populations in patients suffering from spontaneous abortions

A multicascade of leukocyte-endothelial cell interactions is involved in the trafficking of inflammatory lymphocytes into tissue. The primary contact between leukocytes and endothelium is mediated by selectins. Ligands for P-Selectin are preferentially expressed on Th1 cells and thereby allow migration of these inflammatory cells through the vessel wall. Since a peripheral and local Th1-type cytokine profile is present in spontaneous human abortion (SA), opposed by a Th2 dominant situation in normal pregnancies (NP), we investigated (1) the phenotype of peripheral Th1 cells by flow cytometry, as well as the Th1-type cytokine levels by ELISA, (2) the decidual expression of P- and E-Selectin by immunohistochemistry (IHC), and (3) the phenotype of decidual immunocompetent cells by IHC in patients with NP or SA. We observed enhanced production of IFN-gamma and TNF-alpha in CD8(+), CD3(+), and CD56(+) blood cells, as well as an increase in the number of CCR5(+) cells in patients suffering from SA compared to those with NP. No difference was detectable with respect to the serum levels of the two cytokines. Using IHC methods, we observed increased staining intensity of P-Selectin(+) vessels in samples of SA patients. E-Selectin was only weakly expressed in decidual endothelial cells, with no difference between NP and SA. In SA samples, E-Selectin(+) stromal cells were exclusively present. We further detected increased numbers of decidual CD8(+), CD3(+), CCR5(+), and CD56(+) cells in SA patients. We propose that Th1 lymphocyte migration into decidua is enhanced in SA due to upregulated P-Selectin expression in decidual vessels. This increase of Th1-producing lymphocytes might be involved in the rejection of trophoblasts.

Indications for a 'brain-hair follicle axis (BHA)': inhibition of keratinocyte proliferation and up-regulation of keratinocyte apoptosis in telogen hair follicles by stress and substance P

It has long been suspected that stress can cause hair loss, although convincing evidence of this has been unavailable. Here, we show that in mice sonic stress significantly increased the number of hair follicles containing apoptotic cells and inhibited intrafollicular keratinocyte proliferation in situ. Sonic stress also significantly increased the number of activated perifollicular macrophage clusters and the number of degranulated mast cells, whereas it down-regulated the number of intraepithelial gd T lymphocytes. These stress-induced immune changes could be mimicked by injection of the neuropeptide substance P in nonstressed mice and were abrogated by a selective substance P receptor antagonist in stressed mice. We conclude that stress can indeed inhibit hair growth in vivo, probably via a substance P-dependent activation of macrophages and/or mast cells in the context of a brain-hair follicle axis.

Stress and immune mediators in miscarriage

BACKGROUND

Stress is thought to be abortogenic and psycho-neuro-immunological pathways have been suggested to be involved in triggering miscarriages. From experiments in pregnant mice exposed to stress some insights into the underlying mechanisms have been gained, delineating immunological imbalances as a cause of pregnancy failure. In order to test the validity of the conclusions drawn from murine experiments and the role of stress in human pregnancy loss, the following study was performed.

METHODS

We used an established perceived stress questionnaire and measured the stress score of women with a confirmed diagnosis of first trimester spontaneous abortion (n = 94). Decidual tissue was investigated by immunohistochemistry and in-situ hybridization to detect the presence and distribution of immunocompetent decidual cells [CD56(+) natural killer (NK) cells, CD8(+)and CD3(+) T cells, tryptase(+) mast cells (MCT(+)) and tumour necrosis factor (TNF)-alpha(+) cells]. The patient cohort was divided into women experiencing low or high levels of stress.

RESULTS

In the decidua of women with high stress scores we observed significantly higher numbers of MCT(+), CD8(+) T cells and TNF-alpha(+) cells per mm(2) tissue (P < or = 0.05). No significant differences between individuals with lower or higher stress scores could be observed with respect to decidual CD56(+) NK and CD3(+) T cells.

CONCLUSIONS

Using a questionnaire to score perceived stress in humans may be a valid approach to assess non-biased stress scores. Stress-triggered abortion in humans, identified by a questionnaire, can be linked to immunological imbalances.

Patterns of proliferation and apoptosis during murine hair follicle morphogenesis

In this study, we have correlated cutaneous apoptosis and proliferation in neonatal mice during hair follicle morphogenesis. We have applied a novel triple- staining technique that uses Ki67 immunoreactivity as a marker of proliferation as well as TUNEL and Hoechst 33342 staining as apoptosis markers. We have also assessed the immunoreactivity of interleukin-1 beta-converting enzyme, caspase 1, a key enzyme in the execution of apoptosis, and of P-cadherin, which has been suggested as a key adhesion receptor in segregating proliferating keratinocytes. The TUNEL data were systematically compared with high resolution light microscopy and transmission electron microscopy data. Virtually all keratinocytes of the developing hair bud were strongly Ki67(+), suggesting that the hair bud is not an epidermal invagination but primarily the product of localized keratinocyte proliferation. As hair follicle development advanced, three distinct foci of proliferation became apparent: the distal outer root sheath around the hair canal, the mid outer root sheath, and the proximal hair matrix. Of these proliferating hair follicle keratinocytes only defined subsets expressed P-cadherin. TUNEL(+) cells in the hair follicle were not found before stage 5 of murine hair follicle morphogenesis. During the early stages of hair follicle development, interleukin-1 beta-converting enzyme immunoreactivity was present on all keratinocytes, but virtually disappeared from the proximal hair follicle epithelium later on. High resolution light microscopy/transmission electron microscopy revealed scattered and clustered apoptotic keratinocytes in all epithelial hair follicle compartments throughout hair follicle development, including its earliest stages. This highlights striking differences in the demarcation of apoptotic hair follicle keratinocytes between the TUNEL technique and high resolution light microscopy/transmission electron microscopy and suggests a role for apoptosis in sculpting the hair follicle even during early hair follicle development.

Pregnancy as a model of controlled invasion might be attributed to the ratio of CD3/CD8 to CD56

PROBLEM

Pregnancy can be considered as a model of successfully controlled tissue invasion. Cellular mediated immunity appears to regulate the controlled invasion of fetal trophoblast cells. In endometrium cancer, a dysregulation of invasive malignant cells can be observed. Since immunocompetent cells are known to be involved in recognition and rejection of 'non-self' antigens, we investigated the presence and distribution pattern of CD3, CD8, CD56, and CD68 positive cells in decidua from normal and failing pregnancies, compared with malignant and benign endometrium.

METHOD OF STUDY

Decidual tissue from first trimester normal pregnancies (NP; n = 15) and abortion (AB; n = 12), endometrial samples from premenopausal women (NE; n = 8), and endometrioid adenocarcinoma (EA; n = 8) were examined by immunohistochemistry using monoclonal antibody against large spectrum cytokeratin, and against the receptors CD3, CD8, CD56 and CD68, respectively.

RESULTS

In NP, we observed 32.5% CD3, 44.7% CD56, and 22.9% CD68+ cells. In AB, we found 36.9% CD3, 45.3% CD56, and 17.8% CD68+ cells. The differences in ratio between normal pregnancy and abortion were not statistically significant. In NE, we counted 39.5% CD3, 30.2% CD56 and 30.2% CD68 cells. In EA, we observed 47.9% CD3, 12.4% CD56 and 39.7% CD68+ cells. The decrease of CD56 positive cells in endometrioid adenocarcinoma was statistically significant. Interestingly, we found 4.1% of cells positive for CD8 in NP, 4.9% in AB, 22.7% in NE, and 48.2% in EA.

CONCLUSIONS

The increase of CD8 cells in NE, and particularly in EA, and decrease of CD56 cells, compared with NP or AB, suggests an interaction between CD8 cells and CD56 cells. Studying different pathological situations in the uterus, such as malignancies or ectopic pregnancies, might help us to understand the mechanisms involved in the maintenance of pregnancy.

[Improved function of the hand in persons with tetraplegia using electric stimulation via implanted electrodes]

Functional Electrical Stimulation (FES) is a controlled use of electrical stimulation of muscle contractions to obtain function. FES is utilised today in the treatment of spinal cord injured individuals for diaphragmatic pacing, bladder and bowel management, ejaculation, walking and hand function, as well as conditioning. We present The Freehand System, which consists of implanted electrodes to arm and hand muscles. This system has now been implanted in the first two Nordic tetraplegics. Candidates are tetraplegics with C5-6 lesions. After implantation it may take 6-8 months before the tetraplegic person can expect to use The Freehand System completely in daily life. The tetraplegic individual can choose between two grasps. The Freehand System can for some few very physically disabled tetraplegics be a good aid to increase their level of activities of daily living and independence. Continued development in the coming years may broaden the indications with benefit for more individuals.

Retinyl esters are hydrolyzed in early endosomes of J774 macrophages

The aim of the current study was to identify the subcellular compartment(s) responsible for the hydrolysis of chylomicron remnant-retinyl esters, in J774.1 cells. The cells were incubated with medium containing chylomicron remnant [(3)H]retinyl ester. Subcellular fractionation was used to separate early endosomes from late endosomes and lysosomes. About 26% and 80% of the total [(3)H]retinyl esters taken up by the J774 cells were hydrolyzed after 10 min and 60 min of chase, respectively. In the early endosomes, there was a 4-fold increase of radioactivity (nearly all radioactivity associated with retinyl esters) during the first 10 min of chase. The radioactivity in early endosomes was reduced by 43% from 10 min to 60 min and remained stable from 60 to 180 min of chase. From 10 to 60 min the amount of retinol in early endosomes increased from 44% to 82%, indicating an efficient hydrolysis of retinyl esters. Less than 10% and 5% of the total cell-associated radioactivity was found in the late endosomes and lysosomes during the entire chase period. In the chase medium, 84% of the total amount of retinoid released during 180 min was present already after 10 min. The percentage of retinol in the medium increased from 25% to 82% during incubation from 10 to 180 min. These data suggest that retinyl esters are endocytosed together with the chylomicron remnant particle and hydrolyzed in the early endosomes in this cell model.-Hagen, E., A. M. Myhre, T. E. Tjelle, T. Berg, and K. R. Norum. Retinyl esters are hydrolyzed in early endosomes of J774 macrophages.

A new role for neurotrophins: involvement of brain-derived neurotrophic factor and neurotrophin-4 in hair cycle control

Neurotrophins exert many biological effects not directly targeted at neurons, including modulation of keratinocyte proliferation and apoptosis in vitro. Here we exploit the cyclic growth and regression activity of the murine hair follicle to explore potential nonneuronal functions of neurotrophins in the skin, and analyze the follicular expression and hair growth-modulatory function of BDNF, NT-4, and their high-affinity receptor, TrkB. The cutaneous expression of BDNF and NT-4 mRNA was strikingly hair cycle dependent and peaked during the spontaneous, apoptosis-driven hair follicle regression (catagen). During catagen, BDNF mRNA and immunoreactivity, as well as NT-4-immunoreactivity, were expressed in the regressing hair follicle compartments, whereas TrkB mRNA and immunoreactivity were seen in dermal papilla fibroblasts, epithelial strand, and hair germ. BDNF or NT-4 knockout mice showed significant catagen retardation, whereas BDNF-overexpressing mice displayed acceleration of catagen and significant shortening of hair length. Finally, BDNF and NT-4 accelerated catagen development in murine skin organ culture. Together, our data suggest that BDNF and NT-4 play a previously unrecognized role in skin physiology as agents of hair growth control. Thus, TrkB agonists and antagonists deserve exploration as novel hair growth-modulatory drugs for the management of common hair growth disorders.

Do hair bulb melanocytes undergo apoptosis during hair follicle regression (catagen)?

The fate of the hair follicle pigmentary unit during the cyclical involution of anagen hair follicles is unknown. Using the C57BL/6 mouse model for hair research, hair follicle melanocytes were examined during the anagen-catagen transformation, comparing spontaneous and pharmacologically induced catagen development. This study shows that both spontaneous catagen and dexamethasone-induced catagen display similar changes in the pigmentary unit. Catagen hair follicles exhibited pigment incontinence in the dermal papilla and in selected outer root sheath keratinocytes. Melanocytes deleted by apoptosis were detected in spontaneous catagen and, more commonly, in dexamethasone-induced catagen, and were identified using transmission electron microscopy by the presence of free premelanosomes in affected cells lacking epithelial specializations, and by the colocalization of TUNEL positivity and tyrosinase-related protein-1 immunoreactivity. By contrast, cyclophosphamide-induced catagen was characterized by the initial retention of melanogenic and dendritic melanocytes in the presence of widespread keratinocyte apoptosis. Melanocyte incontinence and the ectopic distribution of melanin were more severe than in the other forms of catagen. Whereas much of this melanin was extruded, via the hair canal, to the skin surface, hair follicle-derived pigment was also detected within the epidermis, probably derived from pigment-carrying migrating outer root sheath keratinocytes from the proximal hair follicle. Thus, apoptosis may account, at least in part, for the loss of melanogenic melanocytes during spontaneous catagen. Although dexamethasone-induced catagen may provide a useful model for general hair pigmentation research, catagen induced by cyclophosphamide offers an interesting model for studying the response, and relative resistance, of melanocytes to chemical injury.

Generation and cyclic remodeling of the hair follicle immune system in mice

In this immunohistomorphometric study, we have defined basic characteristics of the hair follicle (HF) immune system during follicle morphogenesis and cycling in C57BL/6 mice, in relation to the skin immune system. Langerhans cells and gammadelta T cell receptor immunoreactive lymphocytes were the predominant intraepithelial hematopoietic cells in neonatal mouse skin. After their numeric increase in the epidermis, these cells migrated into the HF, although only when follicle morphogenesis was almost completed. In contrast to Langerhans cells, gammadelta T cell receptor immunoreactive lymphocytes entered the HF only via the epidermis. Throughout HF morphogenesis and cycling, both cell types remained strikingly restricted to the distal outer root sheath. On extremely rare occasions, CD4+ or CD8+ alphabetaTC were detected within the HF epithelium or the sebaceous gland. Major histocompatibility complex class II+, MAC-1+ cells of macrophage phenotype and numerous mast cells appeared very early on during HF development in the perifollicular dermis, and the percentage of degranulated mast cells significantly increased during the initiation of synchronized HF cycling (first catagen). During both depilation- and cyclosporine A-induced HF cycling, the numbers of intrafollicular Langerhans cells, gammadelta T cell receptor immunoreactive lymphocytes, and perifollicular dermal macrophages fluctuated significantly. Yet, no numeric increase of perifollicular macrophages was detectable during HF regression, questioning their proposed role in catagen induction. In summary, the HF immune system is generated fairly late during follicle development, shows striking differences to the extrafollicular skin immune system, and undergoes substantial hair cycle-associated remodeling. In addition, synchronized HF cycling is accompanied by profound alterations of the skin immune system.

N-3 fatty acids and chylomicron metabolism in the rat

Dietary n-3 fatty acids (FAs) reduce postprandial triacylglycerol concentrations in humans by unknown mechanisms. Our goals were to reproduce this phenomenon in the rat, and then to determine the mechanism. In an oral fat tolerance study two groups of rats were fed diets containing 2.1% ethyl esters of n-3 FA or olive oil for 2 weeks. After gavaging with emulsified soybean oil, the postprandial chylomicron triacylglycerol levels in the n-3 FA group were reduced by 40% (P < 0.05). The hypothesis that n-3 FA feeding reduced chylomicron production/secretion from the gut was tested by blocking chylomicron removal with Triton WR1339 before gavaging the rats with the fat load. This completely eliminated the hypochylomicronemic effect suggesting that chylomicron input was not inhibited by n-3 FAs. Chylomicron clearance was studied by injecting chylomicrons containing radioactive retinyl esters and triacylglycerol into rats from both groups. Pre-feeding with n-3 FAs accelerated the removal of chylomicron triacylglycerol and retinyl esters from the plasma with significantly lower fractions of dose remaining at 2, 4, and 8 min post-injection for both tracers. These findings suggest than n-3 FAs reduce postprandial chylomicronemia in the rat by accelerating chylomicron lipid clearance.

Comparison of the effect of fluvastatin, an hydroxymethyl glutaryl coenzyme A reductase inhibitor, and cholestyramine, a bile acid sequestrant, on lipoprotein particles defined by apolipoprotein composition

In a double-blind, parallel-group, randomized study, the effects of fluvastatin (FLUV) 20 and 40 mg/d on lipoprotein particle levels were compared with those of cholestyramine (CME) 16 g/d. Lipoparticles were defined by apolipoprotein composition as either those containing both apolipoprotein (apo) B and apo E or CIII (lipoprotein [Lp] E-B or Lp CIII-B) or those containing apo AI alone (Lp AI) or in association with apo AII (Lp AI-AII). After an 8-week dietary stabilization period, 100 hypercholesterolemic patients were treated with FLUV 20 mg/d for 6 weeks and 40 mg/d for an additional 6 weeks and were compared with 48 hypercholesterolemic subjects treated with CME 16 g/d. Treatment with FLUV (40 mg/d) or CME (16 g/d) for 12 weeks was associated with a significant reduction in plasma cholesterol and low-density lipoprotein (LDL) cholesterol and a significant increase in high-density lipoprotein (HDL) cholesterol. However, plasma triglyceride levels decreased following FLUV treatment, whereas they increased with CME. These changes were associated with a significant reduction in the levels of apo B (FLUV, -24%, P < .001; CME, -26%, P < .001), apo E (FLUV, -36%, P < .001; CME, -32%, P < .001), and apo CIII (FLUV, -21%, P < .001; CME, -6%, NS).(ABSTRACT TRUNCATED AT 250 WORDS)