Ex Vivo Vascular Imaging and Perfusion Studies of Normal Kidney and Tumor Vasculature

This work describes a comprehensive study of the vascular tree and perfusion characteristics of normal kidney and renal cell carcinoma. Methods: Nephrectomy specimens were perfused ex-vivo, and the regional blood flow was determined by infusion of radioactive microspheres. The vascular architecture was characterized by micronized barium sulphate infusion. Kidneys were subsequently sagitally sectioned, and autoradiograms were obtained to show the perfusate flow in relation to adjacent contact X-ray angiograms. Vascular resistance in defined tissue compartments was quantified, and finally, the tumor vasculature was 3D reconstructed via the micro-CT technique. Results show that the vascular tree of the kidney could be distinctly defined, and autoradiograms disclosed a high cortical flow. The peripheral resistance unit of the whole perfused specimen was 0.78 ± 0.40 (n = 26), while that of the renal cortex was 0.17 ± 0.07 (n = 15 with 114 samples). Micro-CT images from both cortex and medulla defined the vascular architecture. Angiograms from the renal tumors demonstrated a significant vascular heterogeneity within and between different tumors. A dense and irregular capillary network characterized peripheral tumor areas, whereas central parts of the tumors were less vascularized. Despite the dense capillarity, low perfusion through vessels with a diameter below 15 µm was seen on the autoradiograms. We conclude that micronized barium sulphate infusion may be used to demonstrate the vascular architecture in a complex organ. The vascular resistance was low, with little variation in the cortex of the normal kidney. Tumor tissue showed a considerable vascular structural heterogeneity with low perfusion through the peripheral nutritive capillaries and very poor perfusion of the central tumor, indicating intratumoral pressure exceeding the perfusion pressure. The merits and shortcomings of the various techniques used are discussed.

ALK signaling primes the DNA damage response sensitizing ALK-driven neuroblastoma to therapeutic ATR inhibition

High-risk neuroblastoma (NB) is a significant clinical challenge. MYCN and Anaplastic Lymphoma Kinase (ALK), which are often involved in high-risk NB, lead to increased replication stress in cancer cells, suggesting therapeutic strategies. We previously identified an ATR (ataxia telangiectasia and Rad3-related)/ALK inhibitor (ATRi/ALKi) combination as such a strategy in two independent genetically modified mouse NB models. Here, we identify an underlying molecular mechanism, in which ALK signaling leads to phosphorylation of ATR and CHK1, supporting an effective DNA damage response. The importance of ALK inhibition is supported by mouse data, in which ATRi monotreatment resulted in a robust initial response, but subsequent relapse, in contrast to a 14-d ALKi/ATRi combination treatment that resulted in a robust and sustained response. Finally, we show that the remarkable response to the 14-d combined ATR/ALK inhibition protocol reflects a robust differentiation response, reprogramming tumor cells to a neuronal/Schwann cell lineage identity. Our results identify an ability of ATR inhibition to promote NB differentiation and underscore the importance of further exploring combined ALK/ATR inhibition in NB, particularly in high-risk patient groups with oncogene-induced replication stress.

Distinct Cholesterol Localization in Glioblastoma Multiforme Revealed by Mass Spectrometry Imaging

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor in adults and is highly resistant to chemo- and radiotherapies. GBM has been associated with alterations in lipid contents, but lipid metabolism reprogramming in tumor cells is not fully elucidated. One of the key hurdles is to localize the lipid species that are correlated with tumor growth and invasion. A better understanding of the localization of abnormal lipid metabolism and its vulnerabilities may open up to novel therapeutic approaches. Here, we use time-of-flight secondary ion mass spectrometry (ToF-SIMS) to spatially probe the lipid composition in a GBM biopsy from two regions with different histopathologies: one region with most cells of uniform size and shape, the homogeneous part, and the other with cells showing a great variation in size and shape, the heterogeneous part. Our results reveal elevated levels of cholesterol, diacylglycerols, and some phosphatidylethanolamine in the homogeneous part, while the heterogeneous part was dominated by a variety of fatty acids, phosphatidylcholine, and phosphatidylinositol species. We also observed a high expression of cholesterol in the homogeneous tumor region to be associated with large cells but not with macrophages. Our findings suggest that ToF-SIMS can distinguish in lipid distribution between parts within a human GBM tumor, which can be linked to different molecular mechanisms.

Involvement of GABAA receptors containing α6 subtypes in antisecretory factor activity on rat cerebellar granule cells studied by two-photon uncaging

The antisecretory factor (AF) is an endogenous protein that counteracts intestinal hypersecretion and various inflammation conditions in vivo. It has been detected in many mammalian tissues and plasma, but its mechanisms of action are largely unknown. To study the pharmacological action of the AF on different GABA_A receptor populations in cerebellar granule cells, we took advantage of the two‐photon uncaging method as this technique allows to stimulate the cell locally in well‐identified plasma membrane parts. We compared the electrophysiological response evoked by releasing a caged GABA compound on the soma, the axon initial segment and neurites before and after administering AF‐16, a 16 amino acids long peptide obtained from the amino‐terminal end of the AF protein. After the treatment with AF‐16, we observed peak current increases of varying magnitude depending on the neuronal region. Thus, studying the effects of furosemide and AF‐16 on the electrophysiological behaviour of cerebellar granules, we suggest that GABA_A receptors, containing the α₆ subunit, may be specifically involved in the increase of the peak current by AF, and different receptor subtype distribution may be responsible for differences in this increase on the cell.

Multimodal chemical imaging of a single brain tissue section using ToF-SIMS, MALDI-ToF and immuno/histochemical staining

Cluster ion beam ToF-SIMS and/or MALDI-ToF mass spectrometry imaging (using 1,5-DAN matrix via sublimation) of a single coronal rat brain tissue section followed by classical- or immuno- histochemical staining faclilated a new multimodal chemical imaging workflow allowing complementary correlation of the lipid molecular ion images with the immuno/histological features within cerebellum region of the same brain tisue section.

Dark-field microscopy enhance visibility of CD31 endothelial staining

A simple dark field microscopy technique was used for visualization of blood vessels in normal human renal tissues and carcinoma. Phase contrast condenser ring apt for high power objectives was combined with a 10x objective in order to create a dark field illumination of the specimens examined. The endothelial lining of the vessels had been stained by using CD31 monoclonal antibodies combined with conventional peroxidase immunohistochemistry. The final DAB addition used for this technique induced an intense light scatter in the dark field microscope. This scattered light originating from the endothelial lining made the walls of the bright vessels easily detectable from the dark background.

Elevated intracranial pressure after head trauma can be suppressed by antisecretory factor-a pilot study

Background

Control of intracranial pressure (ICP) is a key element in neurointensive care for directing treatment decisions in patients with severe traumatic brain injury (TBI). The anti-inflammatory protein antisecretory factor (AF) has been demonstrated to reduce experimentally induced high ICP in animal models. This report describes the first steps to investigate the uptake, safety, and influence of AF for reduction of elevated ICP in patients with TBI in a clinical setting.

Method

Four patients with severe TBI (Glasgow Coma Scale < 9) that required neurointensive care with ICP monitoring due to signs of refractory intracranial hypertension were investigated. One hundred milliliters of Salovum®, a commercially available egg yolk powder with high contents of AF peptides, was administrated either via nasogastric (patients 1 and 2) or rectal tube (patients 2, 3, and 4) every 8 h for 2 to 3 days as a supplement to the conventional neurointensive care. ICP was registered continuously. Plasma levels of AF were measured by enzyme-linked immunosorbent assay (ELISA) to confirm that Salovum® was absorbed appropriately into the bloodstream.

Results

In the first two patients, we observed that when delivered by the nasogastric route, there was an accumulation of the Salovum® solution in the stomach with difficulties to control ICP due to impaired gastric emptying. Therefore, we tested to administer Salovum® rectally. In the third and fourth patients, who both showed radiological signs of extensive brain edema, ICP could be controlled during the course of rectal administration of Salovum®. The ICP reduction was statistically significant and was accompanied by an increase in blood levels of AF. No adverse events that could be attributed to AF treatment or the rectal approach for Salovum® administration were observed.

Conclusions

The outcomes suggest that AF can act as a suppressor of high ICP induced by traumatic brain edema. Use of AF may offer a new therapeutic option for targeting cerebral edema in clinical practice.

Antisecretory factor AF-16 improves vascular access to a rat mammary tumour

Tumor tissue often has an insufficient nutritional supply, in part due to compression of the vascular network from an increased interstitial fluid pressure. We have shown that the antisecretory factor peptide AF-16 can reduce this pressure in experimental rat breast tumors. In this work we studied if AF-16 administration opened up to an increased vascular volume in these tumors. Sprague-Dawley rats were given dimethylbenxanthracene and developed mammary tumors which were studied. Evans Blue was used as an intravascular volume indicator. Under anesthesia the rats were given AF-16 or solvent intranasally, and Evans Blue was injected i.v. 45 min later. Tumors and various organs were dissected and Evans Blue was extracted and colorimetrically quantified. Tumors had a significantly higher vascular volume after AF-16 administration as compared to other organs. Liver and renal vascular volumes were also increased but to a lesser degree than in the tumors. The results indicate that AF16 could be a candidate for increasing vascular access for chemotherapy in cancer therapy.

Brain region-specific amyloid plaque-associated myelin lipid loss, APOE deposition and disruption of the myelin sheath in familial Alzheimer's disease mice

There is emerging evidence that amyloid beta (Aβ) aggregates forming neuritic plaques lead to impairment of the lipid-rich myelin sheath and glia. In this study, we examined focal myelin lipid alterations and the disruption of the myelin sheath associated with amyloid plaques in a widely used familial Alzheimer's disease (AD) mouse model; 5xFAD. This AD mouse model has Aβ₄₂ peptide-rich plaque deposition in the brain parenchyma. Matrix-assisted laser desorption/ionization imaging mass spectrometry of coronal brain tissue sections revealed focal Aβ plaque-associated depletion of multiple myelin-associated lipid species including sulfatides, galactosylceramides, and specific plasmalogen phopshatidylethanolamines in the hippocampus, cortex, and on the edges of corpus callosum. Certain phosphatidylcholines abundant in myelin were also depleted in amyloid plaques on the edges of corpus callosum. Further, lysophosphatidylethanolamines and lysophosphatidylcholines, implicated in neuroinflammation, were found to accumulate in amyloid plaques. Double staining of the consecutive sections with fluoromyelin and amyloid-specific antibody revealed amyloid plaque-associated myelin sheath disruption on the edges of the corpus callosum which is specifically correlated with plaque-associated myelin lipid loss only in this region. Further, apolipoprotein E, which is implicated in depletion of sulfatides in AD brain, is deposited in all the Aβ plaques which suggest apolipoprotein E might mediate sulfatide depletion as a consequence of an immune response to Aβ deposition. This high-spatial resolution matrix-assisted laser desorption/ionization imaging mass spectrometry study in combination with (immuno) fluorescence staining of 5xFAD mouse brain provides new understanding of morphological, molecular and immune signatures of Aβ plaque pathology-associated myelin lipid loss and myelin degeneration in a brain region-specific manner. Read the Editorial Highlight for this article on page 7.

Spatial Lipidomics Reveals Region and Long Chain Base Specific Accumulations of Monosialogangliosides in Amyloid Plaques in Familial Alzheimer's Disease Mice (5xFAD) Brain

Ganglioside metabolism is significantly altered in Alzheimer's disease (AD), which is a progressive neurodegenerative disease prominently characterized by one of its pathological hallmarks, amyloid deposits or "senile plaques". While the plaques mainly consist of aggregated variants of amyloid-β protein (Aβ), recent studies have revealed a number of lipid species including gangliosides in amyloid plaques along with Aβ peptides. It has been widely suggested that long chain (sphingosine) base (LCBs), C18:1-LCB and C20:1-LCB, containing gangliosides might play different roles in neuronal function in vivo. In order to elucidate region-specific aspects of amyloid-plaque associated C18:1-LCB and C20:1-LCB ganglioside accumulations, high spatial resolution (10 μm per pixel) matrix assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS) of gangliosides in amyloid plaques was performed in hippocampal and adjacent cortical regions of 12 month old 5xFAD mouse coronal brain sections from two different stereotaxic coordinates (bregma points, -2.2 and -2.7 mm). MALDI-IMS uncovered brain-region (2 and 3D) and/or LCB specific accumulations of monosialogangliosides (GMs): GM1, GM2, and GM3 in the hippocampal and cortical amyloid plaques. The results reveal monosialogangliosides to be an important component of amyloid plaques and the accumulation of different gangliosides is region and LCB specific in 12 month old 5xFAD mouse brain. This is discussed in relation to amyloid-associated AD pathogenesis such as lipid related immune changes in amyloid plaques, AD specific ganglioside metabolism, and, notably, AD-associated impaired neurogenesis in the subgranular zone.

On-Tissue Chemical Derivatization of Catecholamines Using 4-( N-Methyl)pyridinium Boronic Acid for ToF-SIMS and LDI-ToF Mass Spectrometry Imaging

The analysis of small polar compounds with ToF-SIMS and MALDI-ToF-MS have been generally hindered by low detection sensitivity, poor ionization efficiency, ion suppression, analyte in-source fragmentation, and background spectral interferences from either a MALDI matrix and/or endogenous tissue components. Chemical derivatization has been a well-established strategy for improved mass spectrometric detection of many small molecular weight endogenous compounds in tissues. Here, we present a devised strategy to selectively derivatize and sensitively detect catecholamines with both secondary ion ejection and laser desorption ionization strategies, which are used in many imaging mass spectrometry (IMS) experiments. Chemical derivatization of catecholamines was performed by a reaction with a synthesized permanent pyridinium-cation-containing boronic acid molecule, 4-( N-methyl)pyridinium boronic acid, through boronate ester formation (boronic acid-diol reaction). The derivatization facilitates their sensitive detection with ToF-SIMS and LDI-ToF mass spectrometric techniques. 4-( N-Methyl)pyridinium boronic acid worked as a reactive matrix for catecholamines with LDI and improved the sensitivity of detection for both SIMS and LDI, while the isotopic abundances of the boron atom reflect a unique isotopic pattern for derivatized catecholamines in MS analysis. Finally, the devised strategy was applied, as a proof of concept, for on-tissue chemical derivatization and GCIB-ToF-SIMS (down to 3 μm per pixel spatial resolution) and LDI-ToF mass spectrometry imaging of dopamine, epinephrine, and norepinephrine in porcine adrenal gland tissue sections. MS/MS using collision-induced dissociation (CID)-ToF-ToF-SIMS was subsequently employed on the same tissue sections after SIMS and LDI mass spectrometry imaging experiments, which provided tandem MS information for the validation of the derivatized catecholamines in situ. This methodology can be a powerful approach for the selective and sensitive ionization/detection and spatial localization of diol-containing molecules such as aminols, vic-diols, saccharides, and glycans along with catecholamines in tissue sections with both SIMS and LDI/MALDI-MS techniques.

Adipose tissue and body composition in women six years after gestational diabetes: factors associated with development of type 2 diabetes

Factors differentiating women at highest risk of progression to type 2 diabetes mellitus (T2DM) after gestational diabetes mellitus (GDM) are incompletely known. Our aim was to characterize adipose tissue and body composition in relation to glucose metabolism in women with a history of GDM and to identify factors associated with development of T2DM. We examined glucose tolerance (OGTT), insulin sensitivity (HOMA-IR), body composition (anthropometry, air displacement plethysmography), and blood chemistry in 39 women 6 years after GDM. An adipose tissue biopsy was obtained to assess the size, number, and lipolytic activity of adipocytes, and adipokine release and density of immune cells and blood vessels in adipose tissue. Normal glucose tolerance (NGT) was identified in 31 women and impaired glucose metabolism (IGM) in 8. Women with IGM had higher BMI/fat mass, and related expected adipose tissue features, than women with NGT. Ethnicity was similar in the groups, but numerically there was a higher proportion of European women in the NGT group and a higher proportion of non-European women in the IGM group. BMI was the best discriminator of NGT versus IGM (multivariable logistic regression: OR = 1.34, P < 0.01). Waist-to-height ratio and adipocyte volume were most strongly associated with HOMA-IR (multivariable linear regression: R² = 0.656, P < 0.001). After adjustment for BMI/ethnicity, women with IGM had increased serum adipocyte fatty acid-binding protein, weight gain after index pregnancy, and a lower proportion of fat-free mass. These factors, together with high BMI, abdominal fat distribution, and enlarged adipocytes, may increase the risk of progression to T2DM after GDM.

Free lipid and computerized determination of adipocyte size

The size distribution of adipocytes in a suspension, after collagenase digestion of adipose tissue, can be determined by computerized image analysis. Free lipid, forming droplets, in such suspensions implicates a bias since droplets present in the images may be identified as adipocytes. This problem is not always adjusted for and some reports state that distinguishing droplets and cells is a considerable problem. In addition, if the droplets originate mainly from rupture of large adipocytes, as often described, this will also bias size analysis. We here confirm that our ordinary manual means of distinguishing droplets and adipocytes in the images ensure correct and rapid identification before exclusion of the droplets. Further, in our suspensions, prepared with focus on gentle handling of tissue and cells, we find no association between the amount of free lipid and mean adipocyte size or proportion of large adipocytes.

Dual polarity MALDI imaging mass spectrometry on the same pixel points reveals spatial lipid localizations at high-spatial resolutions in rat small intestine

Sensitive laser desorption/ionization obtained via a sublimation-coated 1,5-diaminonaphthalene (1,5-DAN) matrix allowed dual polarity MALDI-IMS analysis on the same pixel points across the jejunal mucosal region in rat small intestine which yielded high-spatial-resolution (10 μm) ion images of several lipid species correlated with the same histological features.

TRPA1 Mechanoreceptors Mediate the IL-6 Response to a Single PD Dwell in the Rat

BACKGROUND

The development of modern, biocompatible peritoneal dialysis (PD) fluids has not entirely eliminated the local pro-inflammatory effects of PD fluid administration. The present study was performed in order to establish the importance of known signaling pathways connected to mechano-, osmo- and chemo-sensors of the transient receptor potential (TRP) family for the acute inflammatory response to PD.

METHODS

Rats were exposed to a single 4-hour dwell of lactate-buffered, 2.5% glucose, filter-sterilized PD fluid through an implanted PD catheter. In some groups, the PD dwell was preceded by intravenous administration of blockers of TRPV1 (BCTC), TRPA1 (HC030031), or neurokinin 1 (NK1) (Spantide II) receptors. Cytokine messenger ribonucleic acid (mRNA) expressions were quantified in tissue biopsies (real-time polymerase chain reaction [qPCR]), and cytokine concentrations were quantified in dialysate samples by enzyme-linked immunosorbent assay (ELISA). Tissue expressions of TRPV1, TRPA1, and NK1 were evaluated immuno-histochemically.

RESULTS

The PD dwell induced peritoneal synthesis of Il1b, Tnf, and Il6 and a secretion of interleukin-6 (IL-6) into the dialysate. The catheter implantation already induced the transcription of Il1b and Tnf but did not significantly affect Il6 transcription. The Il6 response to the PD dwell could be virtually eliminated by blocking TRPA1 but was not affected by TRPV1 blockade. Blocking the substance P receptor, NK1, produced an insignificant trend towards Il6 inhibition. TRPA1 and NK1 showed a stronger immuno-reactivity than TRPV1 on cells of the peritoneal tissue.

CONCLUSION

The results show that IL-6 synthesis and secretion were connected to acute PD fluid exposure, and this response was triggered by TRPA1 receptors, possibly located to non-neuronal cells.

Macrophage Phenotype Is Associated With the Regenerative Response in Experimental Replacement of the Porcine Esophagus

A porcine model for bridging circumferential defects in the intrathoracic esophagus has been developed in order to improve the treatment of children born with long-gap esophageal atresia. The aim of this study was to identify factors beneficial for tissue regeneration in the bridging area in this model and to describe the histological progression 20 days after replacement with a silicone-stented Biodesign mesh. Resection of 3 cm of intrathoracic esophagus and replacement with a bridging graft was performed in six newly weaned piglets. They were fed through a gastrostomy for 10 days, and then had probe formula orally for another 10 days prior to sacrifice. Two out of six piglets had stent loss prior to sacrifice. In the four piglets with the stent in place, a tissue tube, with visible muscle in the wall, was seen at sacrifice. Histology showed that the wall of the healing area was well organized with layers of inflammatory cells, in-growing vessels, and smooth muscle cells. CD163+ macrophages was seen toward the esophageal lumen. In the animals where the stent was lost, the bridging area was narrow, and histology showed a less organized structure in the bridging area without the presence of CD163+ macrophages. This study indicates that regenerative healing was seen in the porcine esophagus 20 days after replacement of a part of the intrathoracic esophagus with a silicone-stented Biodesign mesh, if the bridging graft is retained. If the graft is lost, the inflammatory pattern changes with invasion of proinflammatory, M1 macrophages in the entire wall, which seems to redirect the healing process toward scar formation.

Body fat mass and the proportion of very large adipocytes in pregnant women are associated with gestational insulin resistance

Background/Objectives:

Pregnancy is accompanied by fat gain and insulin resistance. Changes in adipose tissue morphology and function during pregnancy and factors contributing to gestational insulin resistance are incompletely known. We sought to characterize adipose tissue in trimesters 1 and 3 (T1/T3) in normal weight (NW) and obese pregnant women, and identify adipose tissue-related factors associated with gestational insulin resistance.

Subjects/Methods:

Twenty-two NW and 11 obese women were recruited early in pregnancy for the Pregnancy Obesity Nutrition and Child Health study. Examinations and sampling of blood and abdominal adipose tissue were performed longitudinally in T1/T3 to determine fat mass (air-displacement plethysmography); insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR); size, number and lipolytic activity of adipocytes; and adipokine release and density of immune cells and blood vessels in adipose tissue.

Results:

Fat mass and HOMA-IR increased similarly between T1 and T3 in the groups; all remained normoglycemic. Adipocyte size increased in NW women. Adipocyte number was not influenced, but proportions of small and large adipocytes changed oppositely in the groups. Lipolytic activity and circulating adipocyte fatty acid-binding protein increased in both groups. Adiponectin release was reduced in NW women. Fat mass and the proportion of very large adipocytes were most strongly associated with T3 HOMA-IR by multivariable linear regression (R²=0.751, P<0.001).

Conclusions:

During pregnancy, adipose tissue morphology and function change comprehensively. NW women accumulated fat in existing adipocytes, accompanied by reduced adiponectin release. In comparison with the NW group, obese women had signs of adipocyte recruitment and maintained adiponectin levels. Body fat and large adipocytes may contribute significantly to gestational insulin resistance.

Novel rat models to study primary genital herpes simplex virus-2 infection

In this study we describe that six rat models (SD, WIST, LEW, BN, F344 and DA) are susceptible to intravaginal herpes simplex virus-2 (HSV-2) infection after pre-treatment with progesterone. At a virus dose of 5 × 10(6) PFU of HSV-2, all rat models were infected presenting anti-HSV-2 antibodies, infectious virus in vaginal washes, and HSV-2 DNA genome copies in lumbosacral dorsal root ganglia and the spinal cord. Most of the LEW, BN, F344, and DA rats succumbed in systemic progressive symptoms at day 8-14 post infection, but presented no or mild genital inflammation while SD and WIST rats were mostly infected asymptomatically. Infected SD rats did not reactivate HSV-2 spontaneously or after cortisone treatment. In an HSV-2 virus dose reduction study, F344 rats were shown to be most susceptible. We also investigated whether an attenuated HSV-1 strain (KOS321) given intravaginally, could protect from a subsequent HSV-2 infection. All LEW, BN, and F344 rats survived a primary HSV-1 infection and no neuronal infection was established. In BN and F344 rats, anti-HSV-1 antibodies were readily detected while LEW rats were seronegative. In contrast to naïve LEW, BN, and F344 rats where only 3 of 18 animals survived 5 × 10(6) PFU of HSV-2, 23 of 25 previously HSV-1 infected rats survived a challenge with HSV-2. The described models provide a new approach to investigate protective effects of anti-viral microbicides and vaccine candidates, as well as to study asymptomatic primary genital HSV-2 infection.

The anterior commissure is a pathway for contralateral spread of herpes simplex virus type 1 after olfactory tract infection

Herpes simplex encephalitis (HSE), targeting the limbic system, is the most common cause of viral encephalitis in the Western world. Two pathways for viral entry to the central nervous system (CNS) in HSE have been suggested: either via the trigeminal nerve or via the olfactory tract. This question remains unsettled, and studies of viral spread between the two brain hemispheres are scarce. Here, we investigated the olfactory infection as a model of infection and tropism of herpes simplex virus 1 (HSV-1), the causative agent of HSE, in the CNS of rats. Rats were instilled with HSV-1 in the right nostril and sacrificed 1-6 days post-infection, and tissues were analysed for viral spread using immunohistochemistry and quantitative PCR (qPCR). After nasal instillation, HSV-1 infected mitral cells of the olfactory bulb (OB) on the right side only, followed by limbic encephalitis. As a novel finding, the anterior commissure (AC) conveyed a rapid transmission of virus between the right and the left OB, acting as a shortcut also between the olfactory cortices. The neuronal cell population that conveyed the viral infection via the AC was positive for the water channel protein aquaporin 9 (AQP9) by immunohistochemistry. Quantification of AQP9 in cerebrospinal fluid samples of HSE patients showed increment as compared to controls. We conclude that the olfactory route and the AC are important for the spread of HSV-1 within the olfactory/limbic system of rats and furthermore, we suggest that AQP9 is involved in viral tropism and pathogenesis of HSE.

Uptake of the antisecretory factor peptide AF-16 in rat blood and cerebrospinal fluid and effects on elevated intracranial pressure

Background

AF-16 is a 16-amino-acid-long peptide derived from the amino-terminal part of the endogenous protein, antisecretory factor (AF). AF-16 in vivo has been shown to regulate dysfunctions in the water and ion transport system under various pathological conditions and also to counteract experimentally increased tissue pressure.

Methods

Rats were subjected to a cryogenic brain injury in order to increase the intracranial pressure (ICP). The distribution of AF-16 in blood and CSF after intravenous or intranasal administration was determined in injured and control rats. ICP was monitored in freely moving, awake rats, by means of an epidural pressure transducer catheter connected to a wireless device placed subcutaneously on the skull. The continuous ICP registrations were achieved by means of telemetry.

Results

Intranasal administration of AF-16 resulted in a significantly higher CSF concentrations of AF-16 in injured than in control rats, 1.3 versus 0.6 ng/ml, whereas no difference between injured and control rats was seen when AF-16 was given intravenously. Rats subjected to cryogenic brain injury developed gradually increasing ICP levels. Intranasal administration of AF-16 suppressed the increased ICP to normal values within 30 min.

Conclusion

Optimal AF-16 concentrations in CSF are achieved after intranasal administration in rats subjected to a cryogenic brain injury. The ability of AF-16 to suppress an increased ICP was manifested.

Antisecretory factor effectively and safely stops childhood diarrhoea: a placebo-controlled, randomised study

AIM

We studied the response to high doses of egg yolk containing antisecretory factor (B221® , Salovum®) in young children with acute diarrhoea, presenting to the Children's Hospital, Lahore, Pakistan.

METHODS

In a randomised, placebo-controlled trial, 36 children aged 7 to 60 months with acute diarrhoea of unknown aetiology, with mild-to-moderate dehydration, were randomised to the Salovum® or placebo groups. Initially, 16 grams of Salovum® or ordinary egg yolk (placebo) mixed in oral rehydration salts was given, followed by 8 g every 5 h until recovery. The number and consistency of stools were recorded.

RESULTS

The two groups were comparable in age, gender, duration of diarrhoea, hydration and nutritional status, although the proportion with watery stools was higher in the Salovum® group (p = 0.04). Reduction in the frequency of stools was seen at 7 versus 18 h (p < 0.0001) and normalising of stool consistency was 10 versus 18 h, p < 0.03) in the Salovum® and placebo groups. The overall effect was 35 versus 70 h in the two groups (p = 0.001). No side effects were reported.

CONCLUSION

High doses of AF in the form of Salovum® effectively and safely reduce childhood diarrhoea of a likely broad aetiology.

The peptide AF-16 decreases high interstitial fluid pressure in solid tumors

BACKGROUND

The high interstitial fluid pressure (IFP) in solid tumors restricts the access to nutrients, oxygen and drugs.

MATERIAL AND METHODS

We investigated the ability of the peptide AF-16, involved in water and ion transfer through cell membranes, to lower the IFP in two different solid rat mammary tumors, one chemically induced, slowly growing, and the other transplantable, and rapidly progressing having high cellularity. AF-16 was administered either in the tumor capsule, intranasally or intravenously. The IFP was measured by a miniature fiber optic device.

RESULTS

AF-16 significantly lowered the IFP in both the slowly and the rapidly progressing tumors, whether administrated locally or systemically. The AF-16 induced IFP reduction was maximal after 90 min, lasted at least 3 h, and returned to pretreatment levels in less than 24 h. Topical AF-16 transiently reduced the IFP in the DMBA tumors from 17.7 ± 4.2 mmHg to 8.6 ± 2.1 mmHg.

CONCLUSION

We conclude that AF-16 transiently and reversibly lowered the high IFP in solid tumors during a few hours, which might translate into improved therapeutic efficacy.

Piglet model for studying esophageal regrowth after resection and interposition of a silicone stented small intestinal submucosa tube

PURPOSE

To investigate the use and subsequent healing of a silicone stented small intestinal submucosa (SIS) tube as a full-circumference replacement following surgical resection of the esophagus in piglets.

MATERIAL AND METHODS

Three centimeters of the intrathoracic esophagus was replaced with a silicone stented SIS tube (Cook Medical) in 6 growing piglets. The esophageal stent was retained for 4 weeks. Esophageal dilations were performed, if needed, after stent removal.

RESULTS

The piglets were sacrificed 1-17 weeks after surgery. Recurrent dilations were needed after stent removal. Histology showed that the gap between the resection margins was filled with new loose connective tissue consisting of fibroblasts and few inflammatory cells. In this tissue, intense angiogenesis was seen at the early time points, which then gave way to the proliferation of immature-looking smooth-muscle-like cells in the submucosa, which appeared to stem from the pericytes of the ingrowing capillaries.

CONCLUSIONS

Through using a stented SIS tube as a circumferential esophageal replacement in a piglet model, this study suggests that pericytes from ingrowing capillaries may play a role in the remodeling of the SIS mesh. It remains to be seen if this process gives a favorable end result because stricture formation after stent removal remains a problem.

Adipose tissue has aberrant morphology and function in PCOS: enlarged adipocytes and low serum adiponectin, but not circulating sex steroids, are strongly associated with insulin resistance

CONTEXT

Comprehensive characterization of the adipose tissue in women with polycystic ovary syndrome (PCOS), over a wide range of body mass indices (BMIs), is lacking. Mechanisms behind insulin resistance in PCOS are unclear.

OBJECTIVE

To characterize the adipose tissue of women with PCOS and controls matched pair-wise for age and BMI, and to identify factors, among adipose tissue characteristics and serum sex steroids, that are associated with insulin sensitivity in PCOS.

DESIGN/OUTCOME MEASURES

Seventy-four PCOS women and 31 controls were included. BMI was 18-47 (PCOS) and 19-41 kg/m(2) (controls). Anthropometric variables, volumes of subcutaneous/visceral adipose tissue (magnetic resonance imaging; MRI), and insulin sensitivity (clamp) were investigated. Adipose tissue biopsies were obtained to determine adipocyte size, lipoprotein lipase (LPL) activity, and macrophage density. Circulating testosterone, free testosterone, free 17β-estradiol, SHBG, glycerol, adiponectin, and serum amyloid A were measured/calculated.

RESULTS

Comparison of 31 pairs revealed lower insulin sensitivity, hyperandrogenemia, and higher free 17β-estradiol in PCOS. Abdominal adipose tissue volumes/distribution did not differ in the groups, but PCOS women had higher waist-to-hip ratio, enlarged adipocytes, reduced adiponectin, and lower LPL activity. In regression analysis, adipocyte size, adiponectin, and waist circumference were the factors most strongly associated with insulin sensitivity in PCOS (R(2)=0.681, P < 0.001).

CONCLUSIONS

In PCOS, adipose tissue has aberrant morphology/function. Increased waist-to-hip ratio indicates abdominal/visceral fat accumulation, but this is not supported by MRI. Enlarged adipocytes and reduced serum adiponectin, together with a large waistline, rather than androgen excess, may be central factors in the pathogenesis/maintenance of insulin resistance in PCOS.

Antisecretory factor-inducing therapy improves the clinical outcome in patients with Ménière's disease

CONCLUSION

Intake of antisecretory factor (AF)-inducing SPC-flakes significantly reduced vertigo in patients suffering from Ménière's disease (MD). The positive effect may be due to a modulation of the transport of water and ions in the endolymphatic space.

OBJECTIVE

To evaluate the effects of a 3-month treatment period with SPC-flakes in patients suffering from MD.

PATIENTS AND METHODS

A prospective, double-blind, placebo-controlled study was performed. A total of 51 adult patients with MD were included in the study: 27 subjects treated with SPC-flakes and 24 subjects with control cereals. The patients received SPC-flakes or control cereals (1 g per kg body weight per 24 h in two servings) for 3 months. Otoneurological examinations were carried out before and after this period.

RESULTS

The severity of MD was classified according to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) grading system. Fourteen of the 27 patients randomized to intake of the AF-inducing SPC-flakes reported decreased vertigo, compared with 2 of 24 in the control group (p < 0.001). No consistent change in the otoneurological examinations could be demonstrated in any of the groups of patients.

Development of monoclonal antibodies for detection of Antisecretory Factor activity in human plasma

Antisecretory Factor (AF) is expressed in most tissues and can be demonstrated in plasma and other body fluids. Most of the AF in plasma is in an inactive form and activation of AF occurs after exposure to bacterial toxins or after intake of various dietary components. Patients with chronic diseases involving disturbances in inflammatory and secretory processes may benefit from an AF-inducing diet. The aim of the present study was to develop an in vitro assay for the analysis of AF-activity in human plasma. Monoclonal antibodies were raised against a native form of AF prepared from human placenta. Nine clones of the monoclonal antibodies recognizing AF and AF peptides were identified. With the aid of these antibodies, we developed a sensitive ELISA method for direct detection of AF-activity in human plasma. The AF activity in plasma from five healthy volunteers was low, 0.112+/-0.022 (absorbance at 405 nm), before intake of the AF-inducing diet with the SPC-Flakes, and increased significantly (p<0.05) to 0.444+/-0.068 after >or=6 weeks on the diet. A comparison of the plasma-AF values, obtained by the bioassay and the immunogenic assay (indirect ELISA), shows that there is a significant correlation (r=0.85) between the values from the two methods. The results indicate that the ELISA measures AF-activity and has the potential to be an important tool for the analysis of AF-activity in further clinical studies on AF-therapy.

Identification of flotillin-1 as an interacting protein for antisecretory factor

Antisecretory factor (AF) also named S5a/Rpn10 was originally identified through its capacity to inhibit intestinal hypersecretion and was later shown to be a component in the proteasome complex. AF is also a potent anti-inflammatory agent and can act as a neuromodulator. In this study we used yeast two-hybrid screens, with yeast strain PJ692A transformed with the bait vector pGBKT7 (AF aa 1-105) against yeast strain Y187 pretransformed with human brain or placenta cDNA libraries, to identify AF-binding proteins. Flotillin-1 was identified as a specific interacting factor with AF. Immunohistochemistry showed co-localization of AF and flotillin-1 in nervous tissue. Flotillin-1 is an integral membrane protein and a component of lipid rafts, a membrane specialization involved in transport processes. Intracellular AF may affect secretory processes by regulating the localization of signal proteins to lipid rafts.

Differential expression of intestinal membrane transporters in cholera patients

Vibrio cholerae causes the cholera disease through secretion of cholera toxin (CT), resulting in severe diarrhoea by modulation of membrane transporters in the intestinal epithelium. Genes encoding membrane-spanning transporters identified as being differentially expressed during cholera disease in a microarray screening were studied by real-time PCR, immunohistochemistry and in a CaCo-2 cell model. Two amino acid transporters, SLC7A11 and SLC6A14, were upregulated in acute cholera patients compared to convalescence. Five other transporters were downregulated; aquaporin 10, SLC6A4, TRPM6, SLC23A1 and SLC30A4, which have specificity for water, serotonin (5-HT), magnesium, vitamin C and zinc, respectively. The majority of these changes appear to be attempts of the host to counteract the secretory response. Our results also support the concept that epithelial cells are involved in 5-HT signalling during acute cholera.

Broad up-regulation of innate defense factors during acute cholera

We used a whole-genome microarray screening system (Affymetrix human GeneChips covering 47,000 different transcripts) to examine the gene expression in duodenal mucosa during acute cholera. Biopsies were taken from the duodenal mucosa of seven cholera patients 2 and 30 days after the onset of diarrhea, and the gene expression patterns in the acute- and convalescent-phase samples were compared pairwise. Of about 21,000 transcripts expressed in the intestinal epithelium, 29 were defined as transcripts that were up-regulated and 33 were defined as transcripts that were down-regulated during acute cholera. The majority of the up-regulated genes characterized were found to have an established or possible role in the innate defense against infections; these genes included the LPLUNC1, LF, VCC1, TCN1, CD55, SERPINA3, MMP1, MMP3, IL1B, LCN2, SOCS3, GDF15, SLPI, CXCL13, and MUC1 genes. The results of confirmative PCR correlated well with the microarray data. An immunohistochemical analysis revealed increased expression of lactoferrin in lamina propria cells and increased expression of CD55 in epithelial cells, whereas increased expression of the SERPINA3 protein (alpha1-antichymotrypsin) was detected in both lamina propria and epithelial cells during acute cholera. The expression pattern of CD55 and SERPINA3 in cholera toxin (CT)-stimulated Caco-2 cells was the same as the pattern found in the intestinal mucosa during acute cholera, indicating that the activation of the CD55 and SERPINA3 genes in intestinal epithelium was induced by CT. In conclusion, during acute cholera infection, innate defense mechanisms are switched on to an extent not described previously. Both direct effects of CT on the epithelial cells and changes in the lamina propria cells contribute to this up-regulation.

Detection of elafin as a candidate biomarker for ulcerative colitis by whole-genome microarray screening

The cause of ulcerative colitis (UC) is largely unknown. Microarray studies are an efficient way of investigating the various genes involved. Here, we have used whole-genome microarrays to clarify the clinical picture and to identify new biomarkers for improved diagnosis. Rectal biopsies were taken from five UC patients and five matched controls, and RNA transcripts were prepared. After labeling, each sample was individually applied to the microarray chips. All transcripts that were more than 10-fold up-regulated in all five patients were analyzed further in seven additional patients and seven controls using quantitative polymerase chain reaction. Of 47,000 transcripts examined, 4 were highly up-regulated in all patients: those encoding elafin, a secreted protease inhibitor, the ion and amino acid transporter B (SLC6A14), and the metabolic enzyme aldolase B, as well as a recently identified transcript named similar to numb-interacting homolog. The up-regulation of these transcripts appears to follow the progression of the disease because elevated expression was detected in the proximal part of the colon in patients with total colitis but not in patients with left-sided colitis. Immunohistologic examination showed very distinct differences in the expression of elafin. Extensive expression was detected in enterocytes and goblet cells of the affected mucosa, whereas there was no detectable expression in unaffected mucosa and in healthy controls. The results implicate four transcripts and proteins of special interest as possible targets for pharmacologic interference and as biomarkers in UC. Of these, elafin may be of special interest because it is a secreted protein that may be measured in body fluids.

Immunohistochemical staining patterns using epitope-specific antibodies indicate conformation variants of antisecretory factor/S5a in the CNS

Antisecretory factor (AF/S5a/Rpn10) was originally identified through its ability to counteract pathological secretion. AF is also a potent anti-inflammatory agent, a neuromodulator, and an important component of the proteasome. Human AF has a calculated molecular mass of 41 kDa and a pI of 4.7. No family of AF-like proteins has been identified. AF has multiple functions in the cell, and different functional forms could exist as a result of post-translational modifications. Epitope-specific antibodies covering the entire length of AF were used to investigate whether modified forms of AF could be detected in the porcine spinal cord by Western blots, 2D gels, and immunohistochemistry (IHC). Western blot and 2D gels showed that all antisera detected a single protein with very similar molecular mass and pI. However, IHC resulted in an epitope-specific subcellular staining pattern. Antisera recognizing epitopes in the N-terminal part of AF, containing the antisecretory activity, showed a more restricted localisation than antisera directed at the C-terminal part, containing the ubiquitin-binding sites. We suggest that AF can exist in several conformational variants, perhaps due to differences in redox state and/or pH in the various cellular compartments. Such conformational changes could be of functional importance.

Separation of human adipocytes by size: hypertrophic fat cells display distinct gene expression

Enlarged adipocytes are associated with insulin resistance and are an independent predictor of type 2 diabetes. To understand the molecular link between these diseases and adipocyte hypertrophy, we developed a technique to separate human adipocytes from an adipose tissue sample into populations of small cells (mean 57.6+/-3.54 microm) and large cells (mean 100.1+/-3.94 microm). Microarray analysis of the cell populations separated from adipose tissue from three subjects identified 14 genes, of which five immune-related, with more than fourfold higher expression in large cells than small cells. Two of these genes were serum amyloid A (SAA) and transmembrane 4 L six family member 1 (TM4SF1). Real-time RT-PCR analysis of SAA and TM4SF1 expression in adipocytes from seven subjects revealed 19-fold and 22-fold higher expression in the large cells, respectively, and a correlation between adipocyte size and both SAA and TM4SF1 expression. The results were verified using immunohistochemistry. In comparison with 17 other human tissues and cell types by microarray, large adipocytes displayed by far the highest SAA and TM4SF1 expression. Thus, we have identified genes with markedly higher expression in large, compared with small, human adipocytes. These genes may link hypertrophic obesity to insulin resistance/type 2 diabetes.

The expression of inhibin beta B is high in human adipocytes, reduced by weight loss, and correlates to factors implicated in metabolic disease

Adipose tissue is an endocrine organ that produces and secretes adipokines. The aim of this study was to identify genes predominantly expressed in human subcutaneous adipocytes. For this purpose, an algorithm was developed and DNA microarray expression profiles from 33 human tissues and cell types were used to select genes. Inhibin beta B (INHBB; coding for the activin betaB subunit) was identified and high expression in adipocytes was confirmed by real-time PCR and immunohistochemistry. INHBB expression in adipose tissue was down regulated by diet-induced weight loss (p<0.001). Furthermore, INHBB expression was positively correlated to total (p<0.001) and subcutaneous (p<0.01) adipose tissue areas and serum levels of fasting insulin (p<0.01) and cholesterol (p<0.05). In conclusion, INHBB expression was high in human adipocytes, reduced by weight loss and adipose tissue INHBB mRNA levels correlated to metabolic risk factors. This suggests that activin B produced in adipocytes may play a role in the metabolic syndrome.

Prenatal exposure to interleukin-6 results in inflammatory neurodegeneration in hippocampus with NMDA/GABAA dysregulation and impaired spatial learning

During pregnancy, infection or immune responses induce cytokine release, which might influence fetal neurodevelopment, leading to neurodegenerative disease in adulthood. Because the hippocampus is a key area for learning and memory, we evaluated 4- and 24-wk-old rats for the effects of early and late prenatal exposure to interleukin-6 (IL-6) on hippocampal morphology, expression of mRNA for IL-6, the γ-aminobutyric acid receptor (GABAAα5), the NR1 subunit of the N-methyl-d-aspartate receptor, and glial fibrillary acidic protein (GFAP), caspase-3 protein and mRNA levels, and learning abilities. Late exposure increased serum IL-6 and hippocampal expression of IL-6 mRNA at 4 and 24 wk. All adult rats showed neuronal loss in the hilus and astrogliosis; males had losses mainly in the CA2 and CA3 regions, and females in CA1. Expression of GABAAα5, NR1, and GFAP mRNA increased in late-exposed males and females at 4 and 24 wk. mRNA and protein levels of the apoptosis marker caspase-3 were increased in all late-exposed rats except males at 4 wk. Evaluation of hippocampus-dependent working memory in the Morris water maze at 20 wk of age showed increases in escape latency and time spent near the pool wall in all IL-6 adult rats, especially females. These findings suggest that fetal IL-6 exposure, especially in late pregnancy, leads to increased IL-6 levels in the circulation and hippocampus, abnormalities of hippocampal structural and morphology, and decreased learning during adulthood.

Plasma cells and Fc receptors in human adipose tissue--lipogenic and anti-inflammatory effects of immunoglobulins on adipocytes

We have previously reported high immunoglobulin expression in human omental adipose tissue. The aim of this work was to investigate plasma cell density and Fc receptor (FcR) expression in human adipose tissue depots and in vitro effects of immunoglobulins on adipocyte function. Plasma cell density was higher in the visceral compared to the subcutaneous depot (10.0+/-1.56% and 5.2+/-0.98%, respectively, n=20, p<0.05). Microarray analysis revealed expression of four FcR genes in adipose tissue; FCGR2A, FCGR2B, FCER1G, and FCGRT. FCGR2A was highly expressed in adipocytes in both depots and this was verified by immunohistochemistry. Expression of IL-1beta and IL-6 was markedly reduced in adipocytes after incubation with the Fc moiety of immunoglobulin G (Fc) (p<0.01). Furthermore, Fc stimulated adipocyte lipogenesis as potently as insulin (p<0.05), but did not influence lipolysis. In conclusion, immunoglobulins produced by plasma cells in human adipose tissue could influence adipocyte metabolism and cytokine production.

Cholera toxin induces a transient depletion of CD8+ intraepithelial lymphocytes in the rat small intestine as detected by microarray and immunohistochemistry

Cholera toxin (CT), besides causing intestinal hypersecretion after intragastric administration or during cholera infection, affects a multitude of regulatory mechanisms within the gut mucosal network, including T cells. By use of microarray screening, real-time PCR, and immunohistochemistry, we demonstrate here a rapid depletion of jejunal CD8(+) intraepithelial lymphocytes (IEL) in rats after intragastric CT challenge. This depletion may depend on CT-induced migration of IEL, since it was associated with a progressive decrease of CD8(+) cells in the epithelium and a contemporary transient increase of such cells, preferentially at the base of the villi, in the lamina propria. A significant decrease in the total number of villous CD8(+) cells at 6 and 18 h after CT challenge was detected; this possibly reflects an efflux from the jejunal mucosa. The kinetics of the CD8(+) IEL demonstrate the return to normal intraepithelial position at original numbers already 72 h after the single CT dose. The induced migration seems to be dependent on the enzymatic A-subunit of CT, since challenge with neither sorbitol nor CT B-subunit did mimic the effects of CT on CD8(+) IEL. Furthermore, a decrease in the level of both RANTES transcript and protein was detected, most likely as a consequence of the CT-induced migration of CD8(+) IEL. These results point to a complex interaction between CT, epithelial cells, and IEL, resulting in a disturbance of the gut homeostasis, which might have relevance for the strong immunomodulatory effects of intragastrically administered CT.

Antisecretory factor modulates GABAergic transmission in the rat hippocampus

Antisecretory Factor (AF) is a protein that has been implicated in the suppression of intestinal hypersecretion and inflammation. Intestinal secretion and inflammation are partly under local and central neural control raising the possibility that AF might exert its action by modulating neural signaling. In the present study we have investigated whether AF can modulate central synaptic transmission. Evoked glutamatergic and GABAergic synaptic transmissions were investigated using extracellular recordings in the CA1 region of hippocampal slices from adult rats. AF (0.5 microg/ml) suppressed GABA(A)-mediated synaptic transmission by about 40% while having no effect on glutamatergic transmission. Per oral administration of cholera toxin as well as feeding of rats with a diet containing hydrothermally processed cereals, known to upregulate endogenous AF plasma activity, mimicked the effect of exogenously administered AF on hippocampal GABAergic transmission. Our results identify AF as a neuromodulator and further raise the possibility that the hippocampus and AF are involved in a gut-brain loop controlling intestinal secretion and inflammation.

Early disturbance of microvascular function precedes chemotherapy-induced intestinal injury

Intestinal injury 4-48 hr after cytotoxic therapy (etoposide phosphate, 100 mg/kg body weight [bw], intravenously [i.v.]) was studied in rats using ligated intestinal loops. Chromium-51 ethylenediaminetetraacetic acid ((51)Cr-EDTA) and rubidium-86 chloride ((86)RbCl) were deposited intraluminally to determine the extent of the increase in intestinal permeability and ion channel disruption. Evans Blue (EB) was used for detection of endothelial leakage. Intestinal morphology was documented. Endothelial dysfunction, as observed by an increased extravasation of EB, was evident already 4 hr after cytotoxic therapy. Intestinal epithelial injury, as observed by an increase in (51)Cr-EDTA permeation and a decrease in (86)Rb absorption, occurred after 48 hr. Finally, histology disclosed a reduced crypt cell proliferation, displayed as a decrease in Ki67-positive cells. The findings suggest that, in the development of intestinal injury after cytotoxic therapy, endothelial disruption is an early event, whereafter epithelial dysfunction and crypt stem cell arrest occur. This knowledge could be of importance in the design of future intervention trials.

A microarray search for genes predominantly expressed in human omental adipocytes: adipose tissue as a major production site of serum amyloid A

To identify genes predominantly expressed in omental adipocytes, microarray expression profiles from 33 human tissues or cell types were analyzed, using an algorithm developed for identification of transcripts predominantly expressed in a certain tissue. Both known adipocyte-specific and more unexpected genes were among the 28 genes identified. To validate the approach, adipocyte expression of three of these genes, acute-phase serum amyloid A (A-SAA), aquaporin 7, and transport secretion protein-2.2, was compared with 17 other human tissues by real-time PCR. The unexpectedly high expression of A-SAA in adipocytes was further verified by Northern blot and immunohistochemistry. The liver, reported to be the main production site for A-SAA, displayed the second highest expression using microarray and real-time PCR. In obese subjects, adipose tissue mRNA and serum A-SAA levels were down-regulated during an 18-wk diet regime (P < 0.05 and P < 0.0001, respectively). A-SAA serum levels were highly correlated to adipose tissue mRNA levels (P < 0.001) and to the total (P < 0.0001) and sc (P < 0.0001) adipose tissue areas, as analyzed by computed tomography. We show that adipose tissue is a major expression site of A-SAA during the nonacute-phase reaction condition. This provides a direct link between adipose tissue mass and a marker for low-grade inflammation and cardiovascular risk.

Increased antisecretory factor reduces vertigo in patients with Ménière's disease: a pilot study

It has been hypothesized that the symptoms of vertigo in patients with Ménière's disease somehow are related to impaired production and/or transport of endolymph. Antisecretory factor (AF) is a protein known to affect transport processes in the intestine and it has been shown that intake of specially processed cereals (SPC) can increase endogenous AF synthesis. In a prospective open pilot study, 24 patients with severe Ménière's disease (functional level scale 5-6 according to the criteria of AAO-HNS) received SPC for 14-30 days. AF levels in plasma increased by 83% in 20 of the 24 patients studied. The attacks of rotatory vertigo were reduced, to final AAO-HNS functional level scale 1-3, in 12 patients and in three of these hearing was normalized. Twelve patients had no or minor effects of the treatment. The correlation between AF activity after treatment and the final AAO-HNS functional level scale was -0.65, P<0.001. Studies in rats using immunohistochemistry methods showed that AF was localized to the cochlea and the vestibule of the inner ear. The present results suggest that AF might be a new regulator of the endolymph.

Antisecretory factor counteracts secretory diarrhoea of endocrine origin

BACKGROUND

Dietary induction of antisecretory factor (AF) can reduce diarrhoea in patients with inflammatory bowel disease. Patients with neuroendocrine tumours may suffer from diarrhoea with a prominent secretory component. We studied if AF-therapy could affect this type of diarrhoea.

METHODS

Six patients with the midgut carcinoid syndrome and two with metastasizing medullary thyroid carcinoma (MTC) participated. Effects of intake of AF, in the form of AF-rich egg powder (AF-egg), and induction of endogenous AF-activity by intake of specially processed cereals (SPCs) were studied. In an initial open part of the study all patients received AF-egg for 4 weeks, followed by a double-blind crossover period with SPC and control cereals (CCs) for 6 weeks each. Daily number of bowel movements at the end of each treatment period was registered.

RESULTS

Treatment with AF-egg resulted in a decrease of bowel movements in seven patients (P<0.01). Registrations of bowel movements from both SPC and CC diet periods were obtained from five patients. The daily number of bowel movements was lower during the SPC-period compared to the period with CC (P<0.05). All patients had low levels of AF-activity in serum at baseline. During treatment with AF-egg, the mean level increased slightly. AF-activity was higher (P<0.05) after SPC compared to the CC diet.

CONCLUSIONS

In a group of patients with endocrine diarrhoea, AF-activity could be induced, and AF-therapy reduced the number of bowel movements.

Cholera toxin induces expression of ion channels and carriers in rat small intestinal mucosa

Cholera toxin causes cyclic adenosine monophosphate (cAMP)-induced electrolyte and water secretion in the small intestine. The toxin-induced change in gene expression in rat small intestine was evaluated with microarray technique and the results were confirmed by semiquantitative polymerase chain reaction (PCR). The transporter CNT2 for nucleosides was upregulated between 6 and 18 h after challenge, whereas the level of GLUT1 transporter for glucose became elevated at 6 h. Both changes probably facilitate uptake of these nutrients in the gut. At 18 h, the major chloride channel in the villus, ClC2, was upregulated. Aquaporin 8 was downregulated at 6 h and two mucin-producing genes were upregulated 18 h after toxin challenge. The expression was back to normal after 72 h, which is the turnover time for intestinal epithelial cells.

Cholera toxin protects against action by Clostridium difficile toxin A. The role of antisecretory factor in intestinal secretion and inflammation in rat

The protein antisecretory factor (AF) inhibits intestinal fluid secretion induced by the cholera toxin (CT) and Clostridium difficile toxin A (CDA). The present work investigated whether CT-induced AF protects against the enterotoxin action by CDA. Rats were pretreated perorally with CT or buffer as control, whereafter CDA-induced fluid secretion and cytotoxicity was tested in vivo in ligated intestinal loops; the mucosal level of AF was estimated using the Western blot technique. Rats given repeated peroral doses of CT became tolerant to CDA, the inhibition of fluid secretion and of cytotoxicity being 79% in eight out of nine animals. The repeated CT-treatment also induced long-lasting rise of AF in the mucosal epithelium. Recombinant AF given either perorally or intravenously inhibited both fluid secretion and cytotoxicity by CDA; similar results were obtained with a truncated 16-mer AF peptide.

IN CONCLUSION

peroral CT-treatment induced tolerance to CDA in rat small intestine. The tolerance was probably mediated by AF induced via action of cholera toxin on the enteric nervous and immune system.

Food-induced antisecretory factor activity is correlated with small bowel length in patients with intestinal resections

Specially processed cereals (SPC) can increase antisecretory factor (AF) activity in humans with an intact intestine. The aim of the present study was to investigate whether AF synthesis could be induced in patients who had been subjected to intestinal resections. Eight patients with varying extents of intestinal resections due to Crohn's disease and six healthy controls participated. All subjects received 54 g SPC daily for 2 weeks. Plasma AF activity was determined before, during and after the treatment period. Baseline diet and medications were kept unchanged. The patients registered the daily number of bowel movements. The SPC diet increased AF activity in all controls. In the patients there was a significant correlation between the length of the remaining small intestine and AF induction (r=0.94, p<0.01) and only those patients with a remaining small intestine of about 3 m reached AF values comparable to those in healthy subjects. It is concluded that small bowel length is related to the ability of humans to induce AF activity by dietary means.