The antisecretory factor: synthesis, anatomical and cellular distribution, and biological action in experimental and clinical studies

Antisecretory factor in breastmilk is associated with reduced incidence of sepsis in preterm infants

BACKGROUND

Antisecretory Factor (AF) is a protein present in breastmilk that regulates inflammatory processes. We aimed to investigate the level of AF in mothers' own milk (MOM) in relation to sepsis and other neonatal morbidities in preterm infants.

METHODS

Samples of breastmilk and infant plasma were collected at 1, 4, and 12 weeks after birth from 38 mothers and their 49 infants born before 30 weeks gestation. AF-compleasome in MOM was determined by a sandwich enzyme-linked immunosorbent assay (ELISA) and inflammatory markers in infant plasma by a panel of 92 inflammatory proteins. Neonatal treatments and outcomes were recorded.

RESULTS

The level of AF in MOM week 1 was lower for infants with later sepsis compared to no sepsis (p = 0.005). Corrected for nutritional intake of MOM, higher levels of AF decreased the risk for sepsis, OR 0.24. AF in MOM week 1 was negatively correlated to inflammatory proteins in infant plasma week 4, markedly IL-8, which was also associated with infant sepsis. Overall, higher AF levels in MOM was associated with fewer major morbidities of prematurity.

CONCLUSION

Mother's milk containing high levels of antisecretory factor is associated with reduced risk for sepsis and inflammation in preterm infants.

IMPACT

High level of antisecretory factor (AF) in mothers' own milk is associated with less risk for later sepsis in preterm infants. Receiving mothers' milk with low AF levels during the first week after birth is correlated with more inflammatory proteins in infant's plasma 2-4 weeks later. Human breastmilk has anti-inflammatory properties, and antisecretory factor in mothers' own milk is a component of potential importance for infants born preterm. The findings suggest that food supplementation with AF to mothers of preterm infants to increase AF-levels in breastmilk may be a means to decrease the risk of inflammatory morbidities of prematurity.

Lifestyle and dietary interventions for Ménière's disease

BACKGROUND

Ménière's disease is a condition that causes recurrent episodes of vertigo, associated with hearing loss and tinnitus. Lifestyle or dietary modifications (including reducing the amount of salt or caffeine in the diet) are sometimes suggested to be of benefit for this condition. The underlying cause of Ménière's disease is unknown, as is the way in which these interventions may work. The efficacy of these different interventions at preventing vertigo attacks, and their associated symptoms, is currently unclear.

OBJECTIVES

To evaluate the benefits and harms of lifestyle and dietary interventions versus placebo or no treatment in people with Ménière's disease.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 14 September 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in adults with Ménière's disease comparing any lifestyle or dietary intervention with either placebo or no treatment. We excluded studies with follow-up of less than three months, or with a cross-over design (unless data from the first phase of the study could be identified).  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were: 1) improvement in vertigo (assessed as a dichotomous outcome - improved or not improved), 2) change in vertigo (assessed as a continuous outcome, with a score on a numerical scale) and 3) serious adverse events. Our secondary outcomes were: 4) disease-specific health-related quality of life, 5) change in hearing, 6) change in tinnitus and 7) other adverse effects. We considered outcomes reported at three time points: 3 to < 6 months, 6 to ≤ 12 months and > 12 months. We used GRADE to assess the certainty of evidence for each outcome.  MAIN RESULTS: We included two RCTs, one related to diet, and the other related to fluid intake and sleep. In a Swedish study, 51 participants were randomised to receive 'specially processed cereals' or standard cereals. The specially processed cereals are thought to stimulate the production of anti-secretory factor - a protein that reduces inflammation and fluid secretion. Participants received the cereals for three months. The only outcome reported by this study was disease-specific health-related quality of life.  The second study was conducted in Japan. The participants (223) were randomised to receive abundant water intake (35 mL/kg/day), or to sleep in darkness (in an unlit room for six to seven hours per night), or to receive no intervention. The duration of follow-up was two years. The outcomes assessed were 'improvement in vertigo' and hearing.  As these studies considered different interventions we were unable to carry out any meta-analysis, and for almost all outcomes the certainty of the evidence was very low. We are unable to draw meaningful conclusions from the numerical results.

AUTHORS' CONCLUSIONS

The evidence for lifestyle or dietary interventions for Ménière's disease is very uncertain. We did not identify any placebo-controlled RCTs for interventions that are frequently recommended for those with Ménière's disease, such as salt restriction or caffeine restriction. We identified only two RCTs that compared a lifestyle or dietary intervention to placebo or no treatment, and the evidence that is currently available from these studies is of low or very low certainty. This means that we have very low confidence that the effects reported are accurate estimates of the true effect of these interventions. Consensus on the appropriate outcomes to measure in studies of Ménière's disease is needed (i.e. a core outcome set) in order to guide future studies in this area and enable meta-analyses of the results. This must include appropriate consideration of the potential harms of treatment, as well as the benefits.

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.

Invited review: strategic adoption of antibiotic-free pork production: the importance of a holistic approach

The discovery of the use of antibiotics to enhance growth in the 1950s proved to be one of the most dramatic and influential in the history of animal agriculture. Antibiotics have served animal agriculture, as well as human and animal medicine, well for more than seven decades, but emerging from this tremendous success has been the phenomenon of antimicrobial resistance. Consequently, human medicine and animal agriculture are being called upon, through legislation and/or marketplace demands, to reduce or eliminate antibiotics as growth promotants and even as therapeutics. As explained in this review, adoption of antibiotic-free (ABF) pork production would represent a sea change. By identifying key areas requiring attention, the clear message of this review is that success with ABF production, also referred to as "no antibiotics ever," demands a multifaceted and multidisciplinary approach. Too frequently, the topic has been approached in a piecemeal fashion by considering only one aspect of production, such as the use of certain feed additives or the adjustment in health management. Based on the literature and on practical experience, a more holistic approach is essential. It will require the modification of diet formulations to not only provide essential nutrients and energy, but to also maximize the effectiveness of normal immunological and physiological capabilities that support good health. It must also include the selection of effective non-antibiotic feed additives along with functional ingredients that have been shown to improve the utility and architecture of the gastrointestinal tract, to improve the microbiome, and to support the immune system. This holistic approach will require refining animal management strategies, including selection for more robust genetics, greater focus on care during the particularly sensitive perinatal and post-weaning periods, and practices that minimize social and environmental stressors. A clear strategy is needed to reduce pathogen load in the barn, such as greater emphasis on hygiene and biosecurity, adoption of a strategic vaccine program and the universal adoption of all-in-all-out housing. Of course, overall health management of the herd, as well as the details of animal flows, cannot be ignored. These management areas will support the basic biology of the pig in avoiding or, where necessary, overcoming pathogen challenges without the need for antibiotics, or at least with reduced usage.

Effect of antisecretory factor, given as a food supplement to adult patients with severe traumatic brain injury (SASAT): protocol for an exploratory randomized double blind placebo-controlled trial

Background

Traumatic brain injury (TBI) constitutes a global epidemic. Overall outcome is poor, with mortality ranging from 10 to 70% and significant long-term morbidity. Several experimental reports have claimed effect on traumatic edema, but no clinical trials have shown effect on edema or outcome. Antisecretory factor, an endogenous protein, is commercially available as Salovum®, which is classified as a medical food by the European Union and has shown effect in experimental trauma models and feasibility with signs of effect in 2 pilot case series. The aim of this study is to assess the effect of antisecretory factor in adult patients with severe traumatic brain injury as measured by 30-day mortality, treatment intensity level (TIL), and intracranial pressure (ICP).

Methods/design

This is a single-center, double-blind, randomized, placebo-controlled clinical phase 2 trial, investigating the clinical superiority of Salovum® given as a food supplement to adults with severe TBI (GCS < 9), presenting to the trauma unit at Tygerberg University Hospital, Cape Town, South Africa, that are planned for invasive ICP monitoring and neurointensive care, will be screened for eligibility, and assigned to either treatment group (n = 50) or placebo group (n = 50). In both groups, the primary outcome will be 30-day mortality, recorded via hospital charts, follow-up phone calls, and the population registry. Secondary outcomes will be treatment intensity level (TIL), scored from hospital charts, and ICP registered from hospital data monitoring.

Trial registration

ClinicalTrials.gov NCT03339505. Registered on September 17, 2017.

Protocol version 3.0 from November 13, 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06275-z.

Intratumoral administration of the antisecretory peptide AF16 cures murine gliomas and modulates macrophage functions

Glioblastoma has remained the deadliest primary brain tumor while its current therapy offers only modest survival prolongation. Immunotherapy has failed to record notable benefits in routine glioblastoma treatment. Conventionally, immunotherapy relies on T cells as tumor-killing agents; however, T cells are outnumbered by macrophages in glioblastoma microenvironment. In this study, we explore the effect of AF16, a peptide from the endogenous antisecretory factor protein, on the survival of glioma-bearing mice, the tumor size, and characteristics of the tumor microenvironment with specific focus on macrophages. We elucidate the effect of AF16 on the inflammation-related secretome of human and murine macrophages, as well as human glioblastoma cells. In our results, AF16 alone and in combination with temozolomide leads to cure in immunocompetent mice with orthotopic GL261 gliomas, as well as prolonged survival in immunocompromised mice. We recorded decreased tumor size and changes in infiltration of macrophages and T cells in the murine glioma microenvironment. Human and murine macrophages increased expression of proinflammatory markers in response to AF16 treatment and the same effect was seen in human primary glioblastoma cells. In summary, we present AF16 as an immunomodulatory factor stimulating pro-inflammatory macrophages with a potential to be implemented in glioblastoma treatment protocols.

Upregulation of the endogenous peptide antisecretory factor enhances hippocampal long-term potentiation and promotes learning in wistar rats

Antisecretory Factor (AF) is an endogenous peptide known for its powerful antisecretory and anti-inflammatory properties. We have previously shown that AF also acts as a neuromodulator of GABAergic synaptic transmission in rat hippocampus in a way that results in disinhibition of CA1 pyramidal neurons. Disinhibition is expected to facilitate the induction of long-term potentiation (LTP), and LTP is known to play a crucial role in learning and memory acquisition. In the present study we investigated the effect of AF on LTP in CA3-CA1 synapses in rat hippocampus. In addition, endogenous AF plasma activity was upregulated by feeding the rats with specially processed cereals (SPC) and spatial learning and memory was studied in the Morris Water Maze (MWM). We found that LTP was significantly enhanced in the presence of AF, both when added exogenously in vitro as well as when upregulated endogenously by SPC-feeding. In the presence of the GABA_A-receptor antagonist picrotoxin (PTX) there was however no significant enhancement of LTP. Moreover, rats fed with SPC demonstrated enhanced spatial learning and short-term memory, compared with control animals. These results show that the disinhibition of GABAergic transmission in the hippocampus by the endogenous peptide AF enhances LTP as well as spatial learning and memory.

Changes in Antisecretory Factor in Human Milk During the Postpartum and Length of Gestation

BACKGROUND

Preterm infants are more susceptible to inflammatory complications than term infants. Human milk contains numerous bioactive components protecting the newborn infant. Antisecretory factor, a protein regulating secretory and inflammatory processes by complex binding with complement factors, is present in human milk.

RESEARCH AIMS

To describe antisecretory factor (1) in mother's own milk in term and preterm infants; and (2) in donor milk before and after Holder pasteurization.

METHODS

The study was prospective, longitudinal, explorative, and descriptive. Antisecretory factor-compleasome was determined using sandwich enzyme-linked immunosorbent assay in longitudinal human milk samples over 12 weeks from mothers (N = 87) of term (n = 41) and of preterm (n = 46) infants and 20 anonymized donor human milk samples before and after Holder pasteurization.

RESULTS

Antisecretory factor-compleasome was overall higher in colostrum versus mature milk (p < .001) and no difference was found in term or preterm colostrum (p = .82). In mature milk, compleasome was higher and more variable in the preterm group (p = .01). After Holder pasteurization, compleasome levels increased (p < .001).

CONCLUSION

Antisecretory factor followed the pattern of other immunological factors with high levels in colostrum. After preterm birth, levels of antisecretory factor were higher and more variable in mature milk. Holder pasteurization did not degrade antisecretory factor, indicating preserved anti-inflammatory properties in donor human milk.

Interventions for preventing mastitis after childbirth

BACKGROUND

Despite the health benefits of breastfeeding, initiation and duration rates continue to fall short of international guidelines. Many factors influence a woman's decision to wean; the main reason cited for weaning is associated with lactation complications, such as mastitis. Mastitis is an inflammation of the breast, with or without infection. It can be viewed as a continuum of disease, from non-infective inflammation of the breast to infection that may lead to abscess formation.

OBJECTIVES

To assess the effectiveness of preventive strategies (for example, breastfeeding education, pharmacological treatments and alternative therapies) on the occurrence or recurrence of non-infective or infective mastitis in breastfeeding women post-childbirth.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (3 October 2019), and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials of interventions for preventing mastitis in postpartum breastfeeding women. Quasi-randomised controlled trials and trials reported only in abstract form were eligible. We attempted to contact the authors to obtain any unpublished results, wherever possible.  Interventions for preventing mastitis may include: probiotics, specialist breastfeeding advice and holistic approaches.   DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trials for inclusion and risk of bias, extracted data and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 10 trials (3034 women). Nine trials (2395 women) contributed data. Generally, the trials were at low risk of bias in most domains but some were high risk for blinding, attrition bias, and selective reporting. Selection bias (allocation concealment) was generally unclear. The certainty of evidence was downgraded due to risk of bias and to imprecision (low numbers of women participating in the trials). Conflicts of interest on the part of trial authors, and the involvement of industry funders may also have had an impact on the certainty of the evidence. Most trials reported our primary outcome of incidence of mastitis but there were almost no data relating to adverse effects, breast pain, duration of breastfeeding, nipple damage, breast abscess or recurrence of mastitis. Probiotics versus placebo Probiotics may reduce the risk of mastitis more than placebo (risk ratio (RR) 0.51, 95% confidence interval (CI) 0.35 to 0.75; 2 trials; 399 women; low-certainty evidence). It is uncertain if probiotics reduce the risk of breast pain or nipple damage because the certainty of evidence is very low. Results for the biggest of these trials (639 women) are currently unavailable due to a contractual agreement between the probiotics supplier and the trialists. Adverse effects were reported in one trial, where no woman in either group experienced any adverse effects. Antibiotics versus placebo or usual care The risk of mastitis may be similar between antibiotics and usual care or placebo (RR 0.37, 95% CI 0.10 to 1.34; 3 trials; 429 women; low-certainty evidence). The risk of mastitis may be similar between antibiotics and fusidic acid ointment (RR 0.22, 95% CI 0.03 to 1.81; 1 trial; 36 women; low-certainty evidence) or mupirocin ointment (RR 0.44, 95% CI 0.05 to 3.89; 1 trial; 44 women; low-certainty evidence) but we are uncertain due to the wide CIs. None of the trials reported adverse effects. Topical treatments versus breastfeeding advice The risk of mastitis may be similar between fusidic acid ointment and breastfeeding advice (RR 0.77, 95% CI 0.27 to 2.22; 1 trial; 40 women; low-certainty evidence) and mupirocin ointment and breastfeeding advice (RR 0.39, 95% CI 0.12 to 1.35; 1 trial; 48 women; low-certainty evidence) but we are uncertain due to the wide CIs. One trial (42 women) compared topical treatments to each other. The risk of mastitis may be similar between fusidic acid and mupirocin (RR 0.51, 95% CI 0.13 to 2.00; low-certainty evidence) but we are uncertain due to the wide CIs. Adverse events were not reported. Specialist breastfeeding education versus usual care The risk of mastitis (RR 0.93, 95% CI 0.17 to 4.95; 1 trial; 203 women; low-certainty evidence) and breast pain (RR 0.93, 95% CI 0.36 to 2.37; 1 trial; 203 women; low-certainty evidence) may be similar but we are uncertain due to the wide CIs. Adverse events were not reported. Anti-secretory factor-inducing cereal versus standard cereal The risk of mastitis (RR 0.24, 95% CI 0.03 to 1.72; 1 trial; 29 women; low-certainty evidence) and recurrence of mastitis (RR 0.39, 95% CI 0.03 to 4.57; 1 trial; 7 women; low-certainty evidence) may be similar but we are uncertain due to the wide CIs. Adverse events were not reported. Acupoint massage versus routine care Acupoint massage probably reduces the risk of mastitis compared to routine care (RR 0.38, 95% CI 0.19 to 0.78;1 trial; 400 women; moderate-certainty evidence) and breast pain (RR 0.13, 95% CI 0.07 to 0.23; 1 trial; 400 women; moderate-certainty evidence). Adverse events were not reported. Breast massage and low frequency pulse treatment versus routine care Breast massage and low frequency pulse treatment may reduce risk of mastitis (RR 0.03, 95% CI 0.00 to 0.21; 1 trial; 300 women; low-certainty evidence). Adverse events were not reported.

AUTHORS' CONCLUSIONS

There is some evidence that acupoint massage is probably better than routine care, probiotics may be better than placebo, and breast massage and low frequency pulse treatment may be better than routine care for preventing mastitis. However, it is important to note that we are aware of at least one large trial investigating probiotics whose results have not been made public, therefore, the evidence presented here is incomplete. The available evidence regarding other interventions, including breastfeeding education, pharmacological treatments and alternative therapies, suggests these may be little better than routine care for preventing mastitis but our conclusions are uncertain due to the low certainty of the evidence. Future trials should recruit sufficiently large numbers of women in order to detect clinically important differences between interventions and results of future trials should be made publicly available.

The antisecretory peptide AF-16 may modulate tissue edema but not inflammation in experimental peritonitis induced sepsis

Sepsis is a life-threatening condition due to a dysregulated immunological response to infection. Apart from source control and broad-spectrum antibiotics, management is based on fluid resuscitation and vasoactive drugs. Fluid resuscitation implicates the risk of volume overload, which in turn is associated with longer stay in intensive care, prolonged use of mechanical ventilation and increased mortality. Antisecretory factor (AF), an endogenous protein, is detectable in most tissues and in plasma. The biologically active site of the protein is located in an 8-peptide sequence, contained in a synthetic 16-peptide fragment, named AF-16. The protein as well as the peptide AF-16 has multiple modulatory effects on abnormal fluid transport and edema formation/resolution as well as in a variety of inflammatory conditions. Apart from its' anti-secretory and anti-inflammatory characteristics, AF is an inhibitor of capillary leakage in intestine. It is not known whether the protein AF or the peptide AF-16 can ameliorate symptoms in sepsis. We hypothesized that AF-16 decreases the degree of hemodynamic instability, the need of fluid resuscitation, vasopressor dose and tissue edema in fecal peritonitis. To test the hypothesis, we induced peritonitis and sepsis by injecting autologous fecal solution into abdominal cavity of anesthetized pigs, and randomized (in a blind manner) the animals to intervention (AF-16, n = 8) or control (saline, n = 8) group. After the onset of hemodynamic instability (defined as mean arterial pressure < 60 mmHg maintained for > 5 minutes), intervention with AF-16 (20 mg/kg (50 mg/ml) in 0.9% saline) intravenously (only the vehicle in the control group) and a protocolized resuscitation was started. We recorded respiratory and hemodynamic parameters hourly for twenty hours or until the animal died and collected post mortem tissue samples at the end of the experiment. No differences between the groups were observed regarding hemodynamics, overall fluid balance, lung mechanics, gas exchange or histology. However, liver wet-to-dry ratio remained lower in AF-16 treated animals as compared to controls, 3.1 ± 0.4, (2.7-3.5, 95% CI, n = 8) vs 4.0 ± 0.6 (3.4-4.5, 95% CI, n = 8), p = 0.006, respectively. Bearing in mind the limited sample size, this experimental pilot study suggests that AF-16 may inhibit sepsis induced liver edema in peritonitis-sepsis.

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.

Antisecretory Factor May Reduce ICP in Severe TBI-A Case Series

Traumatic brain injury (TBI) constitutes a global epidemic. Overall outcome is poor, with mortality ranging from 10 to 70% and significant long-term morbidity. Several experimental reports have claimed effect on traumatic edema, but all clinical trials have failed. Antisecretory factor, an endogenous protein, is commercially available as Salovum®, which is classified as a medical food by the European Union and has been proven effective in experimental trauma models. It has, however, previously not been tested in humans with severe TBI. We hereby report a case series of five adult patients with severe TBI, treated with Salovum. The objective of the intervention was to evaluate safety and, if possible, its effect on intracranial pressure and outcome. Patients received 1 g Salovum per kilo of body weight divided into six doses per 24 h. Each dose was administered through the nasogastric tube. Patients were scheduled for 5 days of treatment with Salovum. Intracranial pressure was controlled in all patients. In three of five patients, intracranial pressure could be controlled with Salovum and deep sedation (no barbiturates), except during periods of gastroparesis. Five of five patients had a favorable short-term outcome, and four of five patients had a favorable long-term outcome. No toxicity was observed. We conclude that at least three of the five treated patients experienced an effect of Salovum with signs of reduction of intracranial pressure and signs of clinical benefit. In order to validate the potential of antisecretory factor in TBI, a prospective, randomized, double-blind, placebo-controlled trial with Salovum has been initiated. Primary outcome for the trial is 30-day mortality; secondary outcomes are treatment intensity level, intracranial pressure, and number of days at the neurointensive care unit.

Does the antisecretory peptide AF-16 reduce lung oedema in experimental ARDS?

Background: Acute respiratory distress syndrome (ARDS) is an acute inflammatory condition with pulmonary capillary leakage and lung oedema formation. There is currently no pharmacologic treatment for the condition. The antisecretory peptide AF-16 reduces oedema in experimental traumatic brain injury. In this study, we tested AF-16 in an experimental porcine model of ARDS.Methods: Under surgical anaesthesia 12 piglets were subjected to lung lavage followed by 2 hours of injurious ventilation. Every hour for 4 hours, measurements of extravascular lung water (EVLW), mechanics of the respiratory system, and hemodynamics were obtained.Results: There was a statistically significant (p = 0.006, two-way ANOVA) reduction of EVLW in the AF-16 group compared with controls. However, this was not mirrored in any improvement in the wet-to-dry ratio of lung tissue samples, histology, inflammatory markers, lung mechanics, or gas exchange.Conclusions: This pilot study suggests that AF-16 might improve oedema resolution as indicated by a reduction in EVLW in experimental ARDS.

The Antisecretory Factor in Plasma and Breast Milk in Breastfeeding Mothers-A Prospective Cohort Study in Sweden

Inflammation and infection postpartum threaten the mother and her infant. Human milk provides a defense for the infant, but inflammatory complications like mastitis may lead to the cessation of breastfeeding. Antisecretory factor (AF) has a role in the regulation of secretory processes and inflammation. The objective of the study was to describe AF-levels in plasma and breast milk, and in relation to breast complications. Breastfeeding mothers (n = 95) were consecutively recruited at a Well Baby Clinic in Umeå, Sweden. At inclusion four weeks postpartum, samples of venous blood (10 mL) and breast milk (10 mL) were collected. Active AF was analyzed with ELISA using a monoclonal antibody mAb43, and was detected in all samples of plasma and breast milk with a positive correlation (Spearman coefficient = 0.40, p < 0.001; Pearson correlation = 0.34, p < 0.01). High AF-levels in plasma correlated with high AF-levels in breast milk. The results suggest a co-regulation between active AF in plasma and breastmilk, and/or a local regulation of AF in the breast. Further studies are needed to determine the pathways for the activation of AF-levels in breast milk and plasma.

Increased level of compleasomes in cerebrospinal fluid of patients with herpes simplex encephalitis

Herpes simplex encephalitis (HSE) is a common cause of viral encephalitis (HSV-1) characterised by pronounced inflammation and elevated intracranial pressure. We have shown in a rat model that HSV-1 infection causes an interaction between complement factors and proteasomes, leading to formation of proteasome/complement complexes (compleasomes). Exposure of the proteasome regulatory subunit antisecretory factor 1 (AF1) leads to a decrease in intracranial pressure. The aim of this study was to evaluate the acute and prolonged formation of compleasomes in cerebrospinal fluid (CSF) from patients with HSE. Cerebrospinal fluid samples (n = 55) from 24 HSE patients were analysed for compleasome complexes. Samples from healthy controls (n = 23) and patient controls (n = 27) served as baseline information. Sandwich enzyme-linked immunosorbent assay (ELISA) for proteasomes and their complex formation with complement factor 3 or 4, and Western blot for C3 activation were performed on CSF samples. Increased compleasome formation, both presenting as an initial formation and showing exposure of subunit AF1 in the compleasomes, was found in CSF samples drawn from patients with HSE compared with samples from the control groups (p < 0.0005). The total protein CSF concentration was equal in all groups. The levels were higher in the acute phase compared with late in the disease course (p < 0.0005). Complement 3 breakdown product iC3b was detected in CSF samples of the HSE patients. The early increased formation of compleasomes in CSF suggests that this complex may be involved in host defence against HSE.

Antisecretory Factor-Mediated Inhibition of Cell Volume Dynamics Produces Antitumor Activity in Glioblastoma

Interstitial fluid pressure (IFP) presents a barrier to drug uptake in solid tumors, including the aggressive primary brain tumor glioblastoma (GBM). It remains unclear how fluid dynamics impacts tumor progression and can be targeted therapeutically. To address this issue, a novel telemetry-based approach was developed to measure changes in IFP during progression of GBM xenografts. Antisecretory factor (AF) is an endogenous protein that displays antisecretory effects in animals and patients. Here, endogenous induction of AF protein or exogenous administration of AF peptide reduced IFP and increased drug uptake in GBM xenografts. AF inhibited cell volume regulation of GBM cells, an effect that was phenocopied in vitro by the sodium-potassium-chloride cotransporter 1 (SLC12A2/NKCC1) inhibitor bumetanide. As a result, AF induced apoptosis and increased survival in GBM models. In vitro, the ability of AF to reduce GBM cell proliferation was phenocopied by bumetanide and NKCC1 knockdown. Next, AF's ability to sensitize GBM cells to the alkylating agent temozolomide, standard of care in GBM patients, was evaluated. Importantly, combination of AF induction and temozolomide treatment blocked regrowth in GBM xenografts. Thus, AF-mediated inhibition of cell volume regulation represents a novel strategy to increase drug uptake and improve outcome in GBM. Mol Cancer Res; 16(5); 777-90. ©2018 AACR.

The Role of Ion Transporters in the Pathophysiology of Infectious Diarrhea

Every year, enteric infections and associated diarrhea kill millions of people. The situation is compounded by increases in the number of enteric pathogens that are acquiring resistance to antibiotics, as well as (hitherto) a relative paucity of information on host molecular targets that may contribute to diarrhea. Many forms of diarrheal disease depend on the dysregulation of intestinal ion transporters, and an associated imbalance between secretory and absorptive functions of the intestinal epithelium. A number of major transporters have been implicated in the pathogenesis of diarrheal diseases and thus an understanding of their expression, localization, and regulation after infection with various bacteria, viruses, and protozoa likely will prove critical in designing new therapies. This article surveys our understanding of transporters that are modulated by specific pathogens and the mechanism(s) involved, thereby illuminating targets that might be exploited for new therapeutic approaches.

Antisecretory Factor Modulates GABAA Receptor Activity in Neurons

The antisecretory factor is an endogenous protein found in all mammalian tissues investigated so far. It acts by counteracting intestinal hypersecretion and various forms of inflammation, but the detailed mechanism of antisecretory factor (AF) action is unknown. We tested neuronal GABA_A receptors by means of AF-16, a potent AF peptide derived from amino acids 36-51 from the NH₂ part of AF. Cultured rat cerebellar granule cells were used, and the effects on the GABA-mediated chloride currents were determined by whole-cell patch clamp. Both the neurotransmitter GABA and AF-16 were added by perfusion of the experimental system. A 3-min AF-16 preincubation was more efficacious than 30 s in significantly elevating the rapidly desensitizing GABA-activated chloride current. No effect was found on the tonic, slowly desensitizing current. The GABA-activated current increase by AF-16 demonstrated a low k of 41 pM with a maximal increase of 37% persisting for some minutes after AF washout, independent from GABA concentration. This indicates an effect on the maximal stimulation (E%_Max) excluding an altered affinity between GABA and its receptor. An immunocytochemical fluorescence approach with anti γ2 subunit antibodies demonstrated an increased expression of GABA_A receptors. Thus, both the electrophysiological and the immunofluorescence approach indicate an increased appearance of GABA_A receptors on the neuronal membrane. The rationale of the experiments was to test the effect of AF on a defined neuronal population of GABA_A receptors. The implications of the results on the impact of AF on the enteric nervous system or on brain function are discussed.

Intranasal Administration of the Antisecretory Peptide AF-16 Reduces Edema and Improves Cognitive Function Following Diffuse Traumatic Brain Injury in the Rat

A synthetic peptide with antisecretory activity, antisecretory factor (AF)-16, improves injury-related deficits in water and ion transport and decreases intracranial pressure after experimental cold lesion injury and encephalitis although its role in traumatic brain injury (TBI) is unknown. AF-16 or an inactive reference peptide was administrated intranasally 30 min following midline fluid percussion injury (mFPI; n = 52), a model of diffuse mild-moderate TBI in rats. Sham-injured (n = 14) or naïve (n = 24) animals were used as controls. The rats survived for either 48 h or 15 days post-injury. At 48 h, the animals were tested in the Morris water maze (MWM) for memory function and their brains analyzed for cerebral edema. Here, mFPI-induced brain edema compared to sham or naïve controls that was significantly reduced by AF-16 treatment (p < 0.05) although MWM performance was not altered. In the 15-day survival groups, the MWM learning and memory abilities as well as histological changes were analyzed. AF-16-treated brain-injured animals shortened both MWM latency and swim path in the learning trials (p < 0.05) and improved probe trial performance compared to brain-injured controls treated with the inactive reference peptide. A modest decrease by AF-16 on TBI-induced changes in hippocampal glial acidic fibrillary protein (GFAP) staining (p = 0.11) was observed. AF-16 treatment did not alter any other immunohistochemical analyses (degenerating neurons, beta-amyloid precursor protein (β-APP), and Olig2). In conclusion, intranasal AF-16-attenuated brain edema and enhanced visuospatial learning and memory following diffuse TBI in the rat. Intranasal administration early post-injury of a promising neuroprotective substance offers a novel treatment approach for TBI.

Interaction of Proteasomes and Complement C3, Assay of Antisecretory Factor in Blood

Antisecretory factor (AF) is a protein complex which inhibits inflammation and regulates fluid transport. In this article, two new immunoassays (ELISA) are developed. The first ELISA establishes a 26S proteasome concentration of 0.41±0.03 μg/mL in normal plasma; the second ELISA discloses the binding of proteasomes to complement factor C3. The latter test values increased about tenfold following intake of processed cereals, paralleling with the old AF ELISA. The proteasome/C3 complex is purified and shown to expose hidden antisecretory peptide sequence and contain the inactive C3c protein. These findings might explain the antisecretory and anti-inflammatory effect during AF complex formation.

Mass spectrometric profiling of lipids in intestinal tissue from rats fed cereals processed for medical conditions

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used for lipid profiling of intestine tissue sections from rats fed specially processed cereals and rats fed ordinary feed as a control. This cereal is known to increase the activity of antisecretory factor in plasma and the exact mechanism for the activation process at the cellular level is unclear. ToF-SIMS has been used to track food induced changes in lipid content in intestinal tissue sections to gain insight into the possible mechanisms involved. Data from 20 intestine sections belonging to four different rats from each group of control and specially processed cereals-fed rats were obtained using the stage scan macroraster with a lateral resolution of 5 μm. Data were subsequently subjected to orthogonal partial least squares discriminant analysis. The data clearly show that changes of certain lipids are induced by the specially processed cereal feed. Scores plots show a well-defined separation between the two groups. The corresponding loading plots reveal that the groups separate mainly due to changes of vitamin E, phosphocholine, and phosphosphingolipid fragments, and that for the c18:2 fatty acid. The observed changes in lipids might give insight into the working mechanisms of antisecretory factor in the body, and this has been successfully used to understand the working mechanism of specially processed cereal-induced antisecretory factor activation in intestine.

The role of antisecretory factor in pancreatic exocrine secretion: studies in vivo and in vitro

NEW FINDINGS

What is the central question of this study? Antisecretory factor, an endogenous protein detected in many tissues of the body, is known as an inhibitor of intestinal secretion, but its role in pancreatic exocrine secretory function has not yet been investigated. What is the main finding and its importance? In a rodent model, we show that antisecretory factor reduces pancreatic exocrine secretion, probably via its direct action on the pancreatic acini and via modulation of the enteropancreatic reflexes involving cholecystokinin and sensory nerves. Antisecretory factor (AF) regulates ion and water transport through the intestinal cell membrane. Antisecretory factor inhibits intestinal secretion, but its effect on the exocrine pancreas has not yet been shown. We investigated the effect of AF on pancreatic amylase secretion in vivo and in vitro using pancreatic acini isolated by collagenase digestion. For the in vivo study, Wistar rats were surgically equipped with silicone catheters, inserted into the pancreaticobiliary duct and into the duodenum. Capsaicin was used to deactivate the sensory nerves in turn to assess their involvement in the effects of AF on the exocrine pancreas. Antisecretory factor (1, 3 or 10 μg kg(-1) i.p.) was given in basal conditions or following stimulation of pancreatic secretion with diversion of pancreaticobiliary juice. For the in vitro study, rat pancreatic acini were incubated in the presence of increasing doses of AF (from 10(-8) to 10(-5)  m) alone or in combination with caerulein (10(-12)  m). Cytoplasmic cholecystokinin 1 (CCK1 ) receptor protein was detected by Western blot and immunoprecipitation studies. Antisecretory factor markedly reduced the output of pancreatic amylase both in basal conditions and when stimulated by diversion of pancreaticobiliary juice. Deactivation of the sensory nerves with capsaicin completely reversed the inhibitory effects of AF on the exocrine pancreas. Caerulein-induced enzyme secretion from the pancreatic acini was inhibited by AF, whereas basal secretion was unaffected. Administration of AF to the rats significantly diminished the synthesis of CCK1 receptor protein. We conclude that AF inhibits pancreatic exocrine secretion indirectly via sensory nerves and directly decreases amylase release from isolated pancreatic acini. The direct inhibitory action of AF on the exocrine pancreas could be related, at least in part, to a reduction of CCK1 receptors on pancreatic acinar cells.

Secretory diarrhoea: mechanisms and emerging therapies

Diarrhoeal disease remains a major health burden worldwide. Secretory diarrhoeas are caused by certain bacterial and viral infections, inflammatory processes, drugs and genetic disorders. Fluid secretion across the intestinal epithelium in secretory diarrhoeas involves multiple ion and solute transporters, as well as activation of cyclic nucleotide and Ca(2+) signalling pathways. In many secretory diarrhoeas, activation of Cl(-) channels in the apical membrane of enterocytes, including the cystic fibrosis transmembrane conductance regulator and Ca(2+)-activated Cl(-) channels, increases fluid secretion, while inhibition of Na(+) transport reduces fluid absorption. Current treatment of diarrhoea includes replacement of fluid and electrolyte losses using oral rehydration solutions, and drugs targeting intestinal motility or fluid secretion. Therapeutics in the development pipeline target intestinal ion channels and transporters, regulatory proteins and cell surface receptors. This Review describes pathogenic mechanisms of secretory diarrhoea, current and emerging therapeutics, and the challenges in developing antidiarrhoeal therapeutics.

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.

Enhanced cellular uptake of antisecretory peptide AF-16 through proteoglycan binding

Peptide AF-16, which includes the active site of Antisecretory Factor protein, has antisecretory and anti-inflammatory properties, making it a potent drug candidate for treatment of secretory and inflammatory diseases such as diarrhea, inflammatory bowel diseases, and intracranial hypertension. Despite remarkable physiological effects and great pharmaceutical need for drug discovery, very little is yet understood about AF-16 mechanism of action. In order to address interaction mechanisms, we investigated the binding of AF-16 to sulfated glycosaminoglycan, heparin, with focus on the effect of pH and ionic strength, and studied the influence of cell-surface proteoglycans on cellular uptake efficiency. Confocal laser scanning microscopy and flow cytometry experiments on wild type and proteoglycan-deficient Chinese hamster ovary cells reveal an endocytotic nature of AF-16 cellular uptake that is, however, less efficient for the cells lacking cell-surface proteoglycans. Isothermal titration calorimetry provides quantitative thermodynamic data and evidence for that the peptide affinity to heparin increases at lower pH and ionic strength. Experimental data, supported by theoretical modeling, of peptide-glycosaminoglycan interaction indicate that it has a large electrostatic contribution, which will be enhanced in diseases accompanied by decreased pH and ionic strength. These observations show that cell-surface proteoglycans are of general and crucial importance for the antisecretory and anti-inflammatory activities of AF-16.

Antisecretory factor (AF) exerts no effects on intracranial pressure (ICP) waves and ICP in patients with idiopathic normal pressure hydrocephalus and idiopathic intracranial hypertension

BACKGROUND

Antisecretory factor (AF) and derivates thereof counteract brain edema and inflammation, and normalize ICP dynamics. The aim of the present study was to assess whether AF normalized the abnormal ICP waves, indicative of impaired intracranial compliance, seen in patients with idiopathic normal pressure hydrocephalus (iNPH) and idiopathic intracranial hypertension (IIH). The hypothesis was that brain swelling contributes to the abnormal ICP waves.

METHODS

The study enrolled patients undergoing diagnostic ICP wave monitoring for either iNPH or IIH. The ICP waves and ICP were recorded continuously before and after oral administration of Salovum® (0.5 g/kg body weight/day divided by three doses), a freeze-dried egg yolk enriched in AF activity. Mean ICP wave amplitude (MWA), mean ICP wave rise time coefficient (MWRTC), and mean ICP were compared before and after Salovum® administration.

RESULTS

A total of 10 iNPH patients and 8 IIH patients were included. No significant changes in the ICP wave indices or ICP were seen after Salovum® administration. Neither any significant time-dependent effect was observed.

CONCLUSION

The lack of effect of Salovum® on ICP wave indices and ICP in iNPH and IIH may provide indirect evidence that brain swelling does not play a crucial role in the ICP wave indices or ICP of these conditions.

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.

Faecal analysis and plasma complement factor 3c levels at admission for an acute attack of ulcerative colitis are predictive of the need for colectomy

BACKGROUND

Ulcerative colitis is a chronic inflammation limited to the large bowel. Early identification of reliable predictive markers addressing the risk of need for colectomy in a severe attack of ulcerative colitis is of crucial importance.

OBJECTIVE

To evaluate faecal characteristics and peripheral blood tests as predictive markers for subsequent risk of colectomy in a severe attack of ulcerative colitis.

METHODS

This was an observational study. Samples were collected in a cohort of 18 patients with a severe attack of ulcerative colitis. A panel of selected variables was evaluated (faecal characteristics, peripheral blood samples including complement factor 3c, circulating cytokines and antisecretory factor) for ability to predict colectomy. The patients were observed for up to 58 months (median 37.5, range 0.5-58 months) and allocated to one of two groups depending on the clinical outcome on the basis of the need for colectomy.

RESULTS

Seven patients underwent colectomy. The present study showed a positive correlation between increased bowel movements (P=0.01), faecal weight/bowel movement (P=0.03) and complement factor 3c levels (P=0.01) and a need for later colectomy. None of the other laboratory markers investigated were shown to be predictive of risk for later colectomy.

CONCLUSION

Early faecal analysis and measurement of complement factor 3c may be useful as predictive markers of the need for colectomy related to a severe attack of ulcerative colitis.

The endogenous peptide antisecretory factor promotes tonic GABAergic signaling in CA1 stratum radiatum interneurons

Tonic GABAergic inhibition regulates neuronal excitability and has been implicated to be involved in both neurological and psychiatric diseases. We have previously shown that the endogenous peptide antisecretory factor (AF) decreases phasic GABAergic inhibition onto pyramidal CA1 neurons. In the present study, using whole-cell patch-clamp recordings, we investigated the mechanisms behind this disinhibition of CA1 pyramidal neurons by AF. We found that application of AF to acute rat hippocampal slices resulted in a reduction of the frequency, but not of the amplitude, of spontaneous inhibitory postsynaptic currents (sIPSCs) in CA1 pyramidal neurons. Miniature inhibitory postsynaptic currents (mIPSCs), recorded in the presence of tetrodotoxin (TTX), were however not affected by AF, neither in CA1 pyramidal cells, nor in stratum radiatum interneurons. Instead, AF caused an increase of the tonic GABA_A current in stratum radiatum interneurons, leaving the tonic GABAergic transmission in CA1 pyramidal cells unaffected. These results show that the endogenous peptide AF enhances tonic, but not phasic, GABAergic signaling in CA1 stratum radiatum interneurons, without affecting tonic GABAergic signaling in CA1 pyramidal neurons. We suggest that this increased tonic GABAergic signaling in GABAergic interneurons could be a mechanism for the AF-mediated disinhibition of pyramidal neurons.

Diet-induced antisecretory factor prevents intracranial hypertension in a dosage-dependent manner

Intake of specially processed cereal (SPC) stimulates endogenous antisecretory factor (AF) activity, and SPC intake has proven to be beneficial for a number of clinical conditions. The aim of the present study was to investigate the dosage relationship between SPC intake and plasma AF activity and to further correlate achieved AF levels to a biological effect. SPC was fed to rats in concentrations of 5, 10 or 15% for 2 weeks. A further group was fed 5% SPC for 4 weeks. AF activity and the complement factors C3c and factor H were analysed in plasma after the feeding period. Groups of rats fed the various SPC concentrations were subjected to a standardised freezing brain injury, known to induce increases in intracranial pressure (ICP). The AF activity in plasma increased after intake of SPC, in a dosage- and time-dependent manner. The complement factors C3c and factor H increased in a time-dependent manner. Measurements of ICP in animals fed with SPC prior to the brain injury showed that the ICP was significantly lower, compared with that of injured rats fed with a standard feed, and that the change was dose and time dependent. AF activity increases, in a dosage- and time-dependent manner, after intake of SPC. The inverse relationship between ICP after a head injury and the percentage of SPC in the feed indicate that the protective effect is, to a large extent, due to AF.

The peptide AF-16 and the AF protein counteract intracranial hypertension

Intracranial hypertension develops after, for example, trauma, stroke and brain inflammation, and contributes to increased morbidity, mortality, and persistent neuropsychiatric sequelae. Nonsurgical therapy offers limited relief. We investigated whether the peptide AF-16 and the endogenous protein Antisecretory Factor (AF) counteracted abnormal fluid transfer by cells, and lowered raised intracranial pressure (ICP). Adult rats, infected with an encephalitogenic Herpes simplex virus (HSV-1), developed after 5 days' sickness of increasing severity. AF-16 rescued all rats while vehicle treatment only saved 20%. AF-16 from day 4 reduced the ICP in HSV-1-infected rats from 30.7 to 14.6 mmHg and all survived without sequelae. A standardised closed head brain injury in rats raised the ICP. Continuous and intermittent AF-16 kept ICP at an almost normal level. A single dose of AF-16 maintained the raised ICP after a TBI lowered during 3-9 h. The AF protein, enriched in egg yolk, similarly lowered the post-traumatically raised ICP in rats. AF-16 also lowered the ICP in rabbits with diffuse brain injury. We conclude that the peptide AF-16 and the AF protein offer new approaches to treat raised ICP with no side effects.

Antisecretory factor as a potential health-promoting molecule in man and animals

Antisecretory factor (AF) is a protein secreted in plasma and other tissue fluids in mammals with proven antisecretory and anti-inflammatory activity; its immunohistological distribution suggests a role in the immune system. The expression level and the distribution of AF protein are altered during an immunological response. Exposure to bacterial toxins induces secretion of AF in plasma, probably reflecting a natural defence mechanism to agents causing diarrhoea, thereby contributing to a favourable clinical outcome and disease termination. An increase of AF levels in plasma by dietary means, such as specially processed cereals (SPC), has been demonstrated in human subjects and animals. Administration of SPC to patients affected by inflammatory bowel disease, gastroenteritis and Ménière's disease relieved symptoms and improved quality of life. A recent study showed the positive effect of SPC diet supplementation on prevention of the effects of exposure to low levels of blast overpressure in rats, reducing the extent of intracranial pressure increase and cognitive function impairment. AF-rich egg yolk powder improved health status in children suffering acute and chronic diarrhoea, reducing the frequency and increasing the consistency of stools. This kind of functional food could be used for prophylaxis in populations exposed to a high risk of morbidity and mortality caused by diarrhoea and as a complementary therapy in patients affected by chronic intestinal inflammatory disease to improve well-being. In pig husbandry AF-inducing diets, owing to their antisecretory activity and anti-inflammatory action, are a suitable option as an alternative to antibiotic growth promoters to counteract post-weaning diarrhoea.

Low-level blast raises intracranial pressure and impairs cognitive function in rats: prophylaxis with processed cereal feed

There is increasing evidence that even low levels of blast cause brain injury, but little is known about their thresholds and mechanisms. Exposure of rats to 10-60 kPa blasts elevate intracranial pressure (ICP) in a dose-dependent manner and impair cognitive function. We have evaluated a prophylactic measure against these brain injuries in a rat animal model, consisting of feeding them processed cereal. This type of feed is known to ameliorate disturbances in secretion of body fluids and to have anti-inflammatory effects. In humans, intake of processed cereals is effective against intestinal diarrhea and also reduces the symptoms of Ménière's disease. Rats were given either standard laboratory feed or processed cereal feed for 2 weeks before exposure to blast in a shock tube. The ICP was monitored at different time points up to 1 week after exposure to a 60-kPa blast, and for up to 24 h after exposure to a 30-kPa blast. Maximal ICP elevation was reached at 10 h in both groups. In the group of rats on standard feed exposed to 60 kPa, an ICP increase of 145% was noted at 10 h, and the corresponding increase in the rats fed processed cereal feed was only 50%. In rats exposed to a 30-kPa blast, those fed standard feed and processed cereal feed demonstrated increases of ICP of 80% and 40%, respectively. Cognitive function as measured by the Morris water maze was assessed in other groups of rats at 2 days after exposure to 10- or 30-kPa blasts. Their performance was significantly impaired at both exposure levels in rats on standard feed, but no functional impairment was seen in rats fed processed cereal feed.

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.

Effects of a supplementary diet with specially processed cereals in patients with short bowel syndrome

OBJECTIVE

Short bowel syndrome patients frequently experience impaired health-related quality of life. This syndrome is also associated with increased costs for the individuals concerned and the community. Intake of specially processed cereals has been demonstrated to decrease intestinal secretion. This study evaluates the effect of a supplementary diet with specially processed cereals compared with nonprocessed cereals.

METHODS

This investigation is a randomized double-blind, cross-over multicentre prospective study of 26 intestinal resected out patients, considered as short bowel syndrome patients. The patients were divided into groups A or B, in accordance with the first allocated treatment. Subgroup analyses of the underlying diagnoses and type of surgical procedure were performed. The studied parameters were faecal volume, nocturnal stools, abdominal pain/discomfort, health-related quality of life, peripheral blood tests and anthropometric data.

RESULTS

In both groups, intake of nonprocessed cereals significantly decreased the faecal volume. The subgroup analyses of patients with a history of ulcerative colitis (compared with Crohn's disease) and nonileostomy-operated procedure (compared with ileostomi-operated procedure) showed significantly decreased faecal volume during nonprocessed cereals intake. Peripheral blood tests, quality of life and anthropometry were not affected.

CONCLUSION

In this study, nonprocessed cereals seemed to be as effective as specially processed cereals in decreasing faecal volume in general and especially in ulcerative colitis patients (mainly operated with nonileostomy techniques). Our results indicate that use of supplementary cereals is safe for this group of patients, but should optimally include evaluation of the underlying diagnosis and the surgical method used.

The peptide AF-16 abolishes sickness and death at experimental encephalitis by reducing increase of intracranial pressure

Elevated intracranial pressure (ICP) is strongly aggravating the injury at brain inflammation, resulting in persistent neurological and psychiatric malfunctions. There is no efficient pharmacological treatment to achieve beneficial ICP reduction. Here, the peptide AF-16, comprising the amino terminal part of the endogenous protein Antisecretory Factor (AF), was used to suppress the raised ICP in experimental herpes simplex encephalitis (HSE) in rats. Intranasal instillation of the peptide AF-16 counteracted the ICP elevation and the prevalence of ICP spikes, abrogated the neurological morbidity, and abolished the mortality in a dose-dependent manner. AF-16, 25 microg twice daily intranasally, rescued all animals with HSE and abrogated neurological malfunction. In contrast, only 10% of the rats survived if treated with the vehicle. A single intranasal dose of 25 microg AF-16 to a rat displaying overt HSE symptoms reduced the ICP to normal levels within an hour. No effects on viral replication or antigen distribution were demonstrable. Thus, AF-16 abolished the prevalence of sickness signs, ICP elevation, neurological malfunctions and completely prevented deaths. We advocate use of AF-16 for suppression of elevated ICP.

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.

B 221, a medical food containing antisecretory factor reduces child diarrhoea: a placebo controlled trial

AIM

We investigated whether egg yolk in the form of B221 (Salovum), a medical food containing antisecretory factor (AF) might be used for treatment of acute and prolonged diarrhoea.

METHODS

240 children 6-24 months of age, half with acute diarrhoea (<7 days) and half with prolonged diarrhoea (> or = 7 days) were randomly given 2 g of B221 or placebo every 5 h for 3 days, added to an oral rehydration salt solution.

RESULTS

B221 reduced the number of stools in the acute diarrhoea group compared with placebo (day 3, p = 0.0054). Stools normalizing in consistency (day 3, p = 0.053) and recovery within 3 days was commoner in the B221 group (p < 0.001). A successful outcome was recorded in 82.8% in the B221 group, compared to 54.4% in the placebo group. In the group with prolonged diarrhoea the stool consistency normalized earlier in the patients receiving B221 than in the patients receiving placebo (p = 0.008). A successful outcome was obtained in 90.9% and 63.2%, (p = 0.0011) in the B221 and placebo-treated groups respectively.

CONCLUSION

B221, which is a medical food, can be used to significantly improve the condition of children with acute, as well as prolonged diarrhoea caused by a broad range of undefined pathogens.

Session 1: Feeding and infant development breast-feeding and immune function

The newborn receives, via the placenta, maternal IgG antibodies against the microbes present in its surroundings, but such antibodies have a pro-inflammatory action, initiating the complement system and phagocytes. Although the host defence mechanisms of the neonate that involve inflammatory reactivity are somewhat inefficient, this defence system can still have catabolic effects. Breast-feeding compensates for this relative inefficiency of host defence in the neonate by providing considerable amounts of secretory IgA antibodies directed particularly against the microbial flora of the mother and her environment. These antibodies bind the microbes that are appearing on the infant's mucosal membranes, preventing activation of the pro-inflammatory defence. The major milk protein lactoferrin can destroy microbes and reduce inflammatory responses. The non-absorbed milk oligosaccharides block attachment of microbes to the infant's mucosae, preventing infections. The milk may contain anti-secretory factor, which is anti-inflammatory, preventing mastitis in mothers and diarrhoea in infants. Numerous additional factors in the milk are of unknown function, although IL-7 is linked to the larger size of the thymus and the enhanced development of intestinal Tgammadelta lymphocytes in breast-fed compared with non-breast-fed infants. Several additional components in the milk may help to explain why breast-feeding can reduce infant mortality, protecting against neonatal septicaemia and meningitis. It is therefore important to start breast-feeding immediately. Protection is also apparent against diarrhoea, respiratory infections and otitis media. There may be protection against urinary tract infections and necrotizing enterocolitis, and possibly also against allergy and certain other immunological diseases, and tumours. In conclusion, breast-feeding provides a very broad multifactorial anti-inflammatory defence for the infant.

Nutritional management of gut health in pigs around weaning

Early weaning of piglets is often accompanied by a severe growth check and diarrhoea. It is well established that this process is multi-factorial and that post-weaning anorexia and undernutrition are major aetiological factors. Gastrointestinal disturbances include alterations in small intestine architecture and enzyme activities. Recent data indicate transiently-increased mucosal permeability, disturbed absorptive-secretory electrolyte balance and altered local inflammatory cytokine patterns after weaning. These responses appear to operate according to two distinct temporal patterns, an acute response followed by a long-lasting adaptation response. Pigs coexist with a diverse and dense commensal microbiota in their gastrointestinal tract. Most of these microbes are beneficial, providing necessary nutrients or protection against harmful pathogens for the host. The microbial colonisation of the porcine intestine begins at birth and follows a rapid succession during the neonatal and weaning period. Following the withdrawal of sow's milk the young piglets are highly susceptible to enteric diseases partly as a result of the altered balance between developing beneficial microbiota and the establishment of intestinal bacterial pathogens. The intestinal immune system of the newborn piglet is poorly developed at birth and undergoes a rapid period of expansion and specialisation that is not achieved before early (commercial) weaning. Here, new insights on the interactions between feed components, the commensal microbiota and the physiology and immunology of the host gastrointestinal tract are highlighted, and some novel dietary strategies are outlined that are focused on improving gut health. Prebiotics and probiotics are clear nutritional options, while convincing evidence is still lacking for other bioactive substances of vegetable origin.

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.