Characteristic transfer of colostral components into cerebrospinal fluid via serum in neonatal pigs

Unlocking the power of Lactoferrin: Exploring its role in early life and its preventive potential for adult chronic diseases

Nutrition during the early postnatal period exerts a profound impact on both infant development and later-life health. Breast milk, which contains lactoferrin, a dynamic protein, plays a crucial role in the growth of various biological systems and in preventing numerous chronic diseases. Based on the relationship between early infant development and chronic diseases later in life, this paper presents a review of the effects of lactoferrin in early life on neonates intestinal tract, immune system, nervous system, adipocyte development, and early intestinal microflora establishment, as well as the preventive and potential mechanisms of early postnatal lactoferrin against adult allergy, inflammatory bowel disease, depression, cancer, and obesity. Furthermore, we summarized the application status of lactoferrin in the early postnatal period and suggested directions for future research.

Lactoferrin and Its Potential Impact for the Relief of Pain: A Preclinical Approach

Pain is one of the most disabling symptoms of several clinical conditions. Neurobiologically, it is classified as nociceptive, inflammatory, neuropathic and dysfunctional. Opioids and nonsteroidal anti-inflammatory drugs (NSAIDs) are conventionally prescribed for the treatment of pain. Long-term administration of opioids results in the loss of analgesic efficacy, leading to increased dosage, tolerance, and addiction as the main drawbacks of their use, while the adverse effects of NSAIDs include gastric ulcer formation, intestinal bleeding, acute kidney injury, and hepatotoxicity. Lactoferrin is an iron-binding, anti-inflammatory glycoprotein that displays analgesic activities associated, in part, by interacting with the low-density lipoprotein receptor-related protein (LRP), which may result in the regulation of the DAMP-TRAF6-NFκB, NO-cGMP-ATP K⁺-sensitive channel and opioid receptor signaling pathways. This review summarizes and discusses for the first time the analgesic effects of lactoferrin and its presumable mechanisms based on pre-clinical trials. Given its anti-nociceptive and anti-inflammatory properties, lactoferrin may be used as an adjunct to enhance the efficacy and to decrease the tolerogenic effects of canonical therapeutic drugs prescribed for pain treatment.

Staphylococcus epidermidis sepsis induces hypercoagulability in preterm pigs

Gram positive bacteria are a cause of sepsis in human preterm infants, and associates with high mortality and hemostatic dysfunction. It is unknown whether bovine colostrum may protect against sepsis and prevent hemostatic dysfunction. The current study was part of an overall sepsis study investigating Staphylococcus epidermidis (SE) induced sepsis in premature pigs including investigation of the effect of feeding bovine colostrum. The specific hypothesis of this study was that the hemostatic response would be hypercoagulable in septic pigs compared to non-infected controls, and that feeding bovine colostrum would increase the hypercoagulant response. Thromboelastography, activated partial thromboplastin time, prothrombin time and fibrinogen concentration were characterized in SE infected pigs, SE infected pigs fed bovine colostrum, and uninfected controls. All pigs were followed for 24 h. In addition, the same parameters were evaluated in a group of premature pigs and a group of full born pigs all followed for 11 days. SE septic premature pigs were characterized by increased clot strength and decreased fibrinolysis, significantly low platelet count and high fibrinogen concentration. Feeding bovine colostrum did not affect the hemostatic response. Compared to full born pigs, preterm newborn pigs demonstrated reduced clot strength, prolonged prothrombin time and low fibrinogen concentration. In all pigs, the fibrinogen concentration increased 11 days post-partum. To conclude, SE induced sepsis in premature pigs resulted in hypercoagulability. Bovine colostrum did not mitigate the hemostatic response. A hypocoagulable hemostatic response was present in healthy preterm pigs compared to full born pigs, similar to previous reports in infants.

Bioactive Whey Protein Concentrate and Lactose Stimulate Gut Function in Formula-fed Preterm Pigs

OBJECTIVE

Formula feeding is associated with compromised intestinal health in preterm neonates compared with maternal milk, but the mechanisms behind this are unclear. We hypothesized that the use of maltodextrin and whey protein concentrates (WPCs) with reduced bioactivity owing to thermal processing are important factors.

METHOD

Ninety-two cesarean-delivered preterm pigs were fed increasing doses of formulas for 5 days (24-120 mL · kg · day). In experiment 1, 4 groups of pigs (n = 15-16) were fed lactose- or maltodextrin-dominant formulas (lactose/maltodextrin ratios 3:1 or 1:3, respectively), containing WPC with either high or low levels of IgG (WPC1 or WPC2, respectively). In experiment 2, 2 groups of pigs (n = 15-16) were fed lactose-dominant formulas with either a bioactive WPC (BioWPC, produced by reduced thermal-processing) or a conventional WPC (ConWPC).

RESULTS

In experiment 1, pigs fed formula with WPC1 had higher villi, hexose absorption, and lactase activity in small intestine, relative to WPC2, but predominantly with the lactose-dominant formula (all P < 0.05). In experiment 2, the BioWPC product had higher bioactivity, as indicated by higher IgG, lactoferrin, and TGF-β2 levels, and better enterocyte proliferation in vitro. Pigs fed the BioWPC formula showed better feeding tolerance and higher intestinal villi and lactase activity (all P < 0.05). The BioWPC formula-fed pigs also had greater physical activity (P < 0.05 on day 4) and tended to show improved hexose absorption and decreased gut permeability (both P ≤ 0.09).

CONCLUSIONS

Infant formulas containing lactose as the main carbohydrate, and WPC with reduced thermal processing, may support gut maturation and health in sensitive, preterm neonates.

Appearance of immunoglobulin G in the plasma of piglets following intake of colostrum, with or without a delay in sucking

The intake of immunoglobulin G (IgG) by sucking piglets from colostrum was estimated over the first 24 h of sucking by the weigh-suck-weigh technique using experimentally determined correction factors for metabolic and urinary losses and was related to appearance of IgG in piglet plasma. Colostrum immunoglobulin G (IgG) concentrations declined rapidly from 61 mg/ml at the start of sucking to 9·0 mg/ml after 24 h sucking. IgG was first detected in piglet plasma after 4 h sucking, increased to a maximum after 12 to 16 h sucking and thereafter declined. In piglets allowed to suck from birth, there was no significant relationship between estimated IgG intake and plasma IgG concentration suggesting that IgG intake did not limit acquisition of IgG by the piglet. When sucking was delayed by 8 or 12 h, colostrum intakes by piglets were not different from piglets allowed immediate access to the udder but IgG intakes were significantly (P< 0·001) decreased. Total plasma IgG (g/kg live weight) did not decline significantly as a result of delayed sucking. In conclusion, under the experimental conditions employed, the appearance of IgG in piglet plasma was limited by factors other than by colostrum IgG intake.

Intestinal receptor targeting for peptide delivery: an expert's personal perspective on reasons for failure and new opportunities

The technology has been available more than 25 years that would enable the oral delivery of vaccines, proteins and peptides, thus avoiding the need for injection. To this day, injection is still the mode of delivery, yet not the main mode of choice. This review focuses on several of the potential modes for oral delivery of peptides, proteins and vaccines. Additionally, the review will provide the reader with an insight into the problems and potential solutions for several of these modes of oral delivery of peptides and proteins.

Anti-nociceptive effect of bovine milk-derived lactoferrin in a rat lumbar disc herniation model

STUDY DESIGN

An experimental animal study.

OBJECTIVE

We evaluated the efficacy of lactoferrin (LF) compared with diclofenac to reduce the pain, using a rat lumbar disc herniation model.

SUMMARY OF BACKGROUND DATA

LF is a multifunctional protein that is found in milk. Recent studies have reported that LF reduces nociception in various experimental models.

METHODS

Rats were operated on the left L5 vertebral arch. The left L5 nerve root and dorsal root ganglion (DRG) were exposed by a L5 partial laminectomy. An L-shaped stainless steel rod was inserted from the laminectomy toward the intervertebral foramen to compress the nerve root. In addition, nucleus pulposus from coccygeal discs was applied on the nerve root. At 1 day before operation, all rats were tested regarding the withdrawal threshold of the left plantar surface using von Frey filaments to determine baseline values. Additional von Frey tests were performed on postoperative days 3, 7, 14, and 21. Thirty minutes before each test except for baseline, the rats received LF (100 mg/kg), diclofenac (10 mg/kg), or saline by intraperitoneal injection (n = 6).

RESULTS

As compared with the control group, thresholds of rats in the diclofenac group were significantly higher on postoperative days 3 and 7. However, on postoperative days 14 and 21, there were no significant differences. Thresholds of rats in the LF group were significantly higher on all postoperative days compared with the control group.

CONCLUSION

Analgesic effect of diclofenac reduced with time. However, the effect of LF continued during the whole experimental period. LF might become useful as pain-killer.

Persorption Mechanisms of Luminal Antigenic Particulates via Apoptotic Epithelial Cells of Intestinal Villi into Systemic Blood Circulation in Orally Immunized Rats

The possibility of persorption of prefixed bovine serum albumin-coated sheep erythrocytes (BSA-SEs) from mucous epithelial cells and its mechanisms were investigated in rats orally immunized by BSA for 14 consecutive days. On the day after the final oral immunization, the rats were duodenally perfused by BSA-SEs or non-coated SEs. BSA-SEs were also duodenally perfused in non-immunized rats. Thirty min after perfusion, BSA-SEs were significantly more engulfed by late-apoptotic-stage villous columnar epithelial cells in the orally immunized rats than those in other experiments. The specific antibody (SpAb) was detected on the surfaces of BSA-SEs in rats with oral immunization. In Peyer's patches of all animals, no SEs reached the follicle-associated epithelium, because of the close attachment of follicle-associated intestinal villi and the thick mucous layer. BSA-SEs were more frequently persorbed into portal blood in the orally immunized rats than in other rats. Small numbers of BSA-SEs or SEs were detected in the systemic blood of all animals. BSA-SEs were also histologically found in the blood vessels of the liver, but not in mesenteric lymph nodes. These findings suggest that sensitized antigenic particulates are taken up by late-apoptotic-stage villous columnar epithelial cells in the small intestine and are finally persorbed into the systemic blood circulation. The uptake of antigenic particulates might be mediated by its luminal SpAb.

Effect of beta-lactotensin on acute stress and fear memory

beta-Lactotensin (beta-LT) is a bioactive peptide derived from bovine milk beta-lactoglobulin and is a natural ligand for neurotensin receptors. We examined the effect of beta-LT on restraint stress and fear memory in mice. Mice subjected to acute restraint stress exhibited a decreased number of head-dips and increased head-dip latency compared to non-stressed controls in the hole-board test, reflecting increased stress-induced behaviors. However, prior administration of beta-LT improved the behaviors caused by stress. The anti-stress effect of beta-LT was blocked by levocabastine, a neurotensin receptor subtype 2 (NTR2) antagonist. In the fear-conditioning test, the duration of freezing responses by cued fear conditioning was significantly reduced in mice administered beta-LT compared with control mice. These results suggest that beta-LT has an anti-stress effect and promotes the extinction of fear memory, which may be mediated by NTR2.

Effects of lactoferrin supplementation on ileal and total tract nutrient digestibility, gastrointestinal microbial populations, and immune characteristics of ileal cannulated, healthy, adult dogs

Orally supplemented lactoferrin derived from bovine milk is purported to have beneficial effects on gut health of animals. Bovine lactoferrin (0, 60, or 120 mg/d) was fed to ileal cannulated, adult dogs in a replicated 3 x 3 Latin square design with 14 d periods. Control dogs tended (p = 0.06) to have higher fecal DM concentrations compared with dogs supplemented with 120 mg/d lactoferrin (34.5 vs. 32.9%). Fecal scores ranged from 3.0 - 3.3, suggesting that feces of all dogs was near the desired consistency, with dogs supplemented with 120 mg/d lactoferrin tending (p = 0.08) to have higher fecal scores. Ileal azoreductase activity tended (p < 0.10) to be higher in dogs supplemented with 60 or 120 mg/d lactoferrin (609 vs. 592 nmol/h per g ileal DM, respectively) as compared with unsupplemented dogs (272 nmol/h per g ileal DM). The following bacterial groups were measured: bifidobacteria, Campylobacter spp., Clostridium spp., eubacteria, Escherichia coli, Lactobacillus spp., Staphylococcus spp., and Streptococcus spp. Fecal streptococci concentrations were lower (p < 0.05) for dogs receiving 60 mg/d lactoferrin (8.60 log10 cfu/g fecal DM) as compared with unsupplemented dogs (9.19 log10 cfu/g fecal DM) or dogs receiving 120mg lactoferrin/d (9.43 log10 cfu/g fecal DM). Dogs supplemented with 120mg/d lactoferrin tended (p = 0.08) to have higher fecal indole concentrations as compared to unsupplemented dogs (1.80 vs. 1.46 micromol/g fecal DM). Because most bacterial groups measured were unaffected, it appears that lactoferrin did not exhibit prebiotic activity, and based on the data collected, lactoferrin also did not appear to have major effects on indices of health in the dog.

Milk-derived lactoferrin may block tolerance to morphine analgesia

Lactoferrin (LF) is a multifunctional protein that is widely found in milk, blood, and other biological fluids. In the present study, we investigated the possibility that LF may block a tolerance to morphine-induced analgesia in the mouse. The nociceptive effect of bovine milk-derived LF (bLF) was estimated in the mouse tail-flick test. Although an intraperitoneal (100 mg/kg) or an oral (300 mg/kg) administration of bLF did not show remarkable analgesia, a combination with intraperitoneal administration of morphine (3 mg/kg) strikingly enhanced morphine-induced analgesia. Moreover, repeated administration of morphine at doses of 3 mg/kg (ip) or 5 mg/kg (ip) caused a tolerance to the morphine on the 5th or 7th day, respectively. In contrast, the combination of bLF (100 mg/kg, ip) with morphine (3 mg/kg, ip) retarded the development of tolerance to the 9th day, although bLF did not show any effect on the mice that had obtained tolerance to morphine. Furthermore, the potentiative effect of bLF was partially blocked by pre-treatment with N(G)-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide synthase (NOS) inhibitor, and completely blocked by 7-nitroindazole (7-NI), a selective neuronal NOS (nNOS) inhibitor. Methylene blue (MB), a guanylate cyclase (GC) inhibitor, also dose-dependently prevented the potentiative effect of bLF. These results suggest that bLF selectively activates nNOS and then accelerates NO production. The increased NO in turn modulates the GC activity and finally enhances the endogenous opioid system via cyclic guanosine monophosphate production. We conclude that bLF may block the development of tolerance to morphine in mice, possibly via the selective activation of nNOS.

Antinociceptive and antipyretic effects of a derivatized tetrapeptide from lactoferrin in rats

PEP1261, a tetrapeptide derivative used in this study, corresponds to residues 39-42 of human lactoferrin. The parent protein lactoferrin is known to exhibit antinociceptive activity and it regulates many aspects of inflammation. This study is aimed to evaluate the antinociceptive and antipyretic activities of PEP1261 in rats. PEP1261 exhibits a significant dose dependent antinociceptive activity with optimal effect at 40 mg/kg body weight (b.w.) (i.p.) in both tail-flick model and acetic acid induced writhing in rats. PEP1261 at the doses of 20 and 40 mg/kg b.w. (i.p.) is also observed to exhibit notable antipyretic effect in lipopolysaccharide-induced pyrexia in rats. In conclusion, the results suggest that PEP1261 possesses antinociceptive and antipyretic activities better than the control peptide KRDS.

Suppressive effects of milk-derived lactoferrin on psychological stress in adult rats

Lactoferrin (LF) is known as an iron-binding glycoprotein. It has been shown that bovine LF (bLF) is transported into cerebrospinal fluid via blood although its physiological effects in the central nervous system (CNS) are still unclear. In this study, a suppressive effect of bLF on psychological distress was investigated in adult rats. Intraperitoneal injection of bLF (100 mg/kg) reduced stressful behaviors in a conditioned fear-induced freezing test and an elevated plus-maze test. Interestingly, the suppressive effect of bLF was enhanced by pretreatment with electric foot-shock (FS). This suppressive effect of bLF in the elevated plus-maze test was reversed by pretreatment with naloxone, an opioid receptor antagonist, at a dose of 1 mg/kg (ip). N(omega)-nitro-l-arginine methyl ester (l-NAME), a nitric oxide synthase (NOS) inhibitor, also blocked the suppressive effect of bLF and foot-shock. In addition, combined application of a low dose of bLF (30 mg/kg, ip) and l-arginine (30 and 100 mg/kg, ip) showed significant potentiated effects on psychological stress. These results suggest that bLF has suppressive effects on psychological distress, especially under the condition of moderate stress. Furthermore, it is suggested that bLF possibly activates an endogenous opioidergic system via nitric oxide synthase activation.

Differential c-Fos expression in the newborn lamb nucleus tractus solitarius and area postrema following ingestion of colostrum or saline

Visceral stimuli and the gut-brain axis play a crucial role in the control of ingestion even in the neonate. The aim of this study was to assess the neuronal activation in the nucleus tractus solitarius (NTS) and the area postrema (AP) following nutritional and non-nutritional stimulations. Lambs received a single gastric infusion of colostrum or saline at 5% birth weight or were sham infused. Infusion of either liquid led to c-Fos-like immunoreactivity (c-FLI) in the NTS and AP. Differences were observed along the sections of the NTS rostro-caudal axis according to the nature of the stimulation, suggesting a specificity of certain afferents and/or NTS areas for nutritional or non-nutritional signals. In the AP, the neuronal activation induced by colostrum was much higher than that induced by saline. A higher number of TH-immunoreactive cells were activated following colostrum infusion, suggesting a specific involvement of the catecholaminergic pathway in the treatment of meal-related stimuli. In spite of functional convergence, the two medullary structures observed responded differently according to the stimulation, indicating a complementary role in the integration of visceral signals.

Evidence of lactoferrin transportation into blood circulation from intestine via lymphatic pathway in adult rats

Using adult rats, the characteristic transporting system for lactoferrin (LF) from intestinal lumen into the blood circulation was investigated. The rats were randomly divided into two groups, a non-collected thoracic lymph (NC) group and a collected thoracic lymph (LC) group. Peripheral blood and thoracic lymph were collected from a jugular vein and a thoracic lymph duct, respectively, under anaesthesia. Bovine LF (bLF) was infused into the duodenal lumen by needle over a 1-min period at a dose of 1 g kg(-1). The transported bLF in the plasma and lymph was assayed quantitatively by double-antibody enzyme-linked immunosorbent assay (ELISA). Morphological investigation was also carried out in the intestine, lymph node, and liver. Following intraduodenal administration of bLF, the transported bLF in the NC group was detected in the plasma, and reached a peak value at 2 h. Furthermore, the bLF concentration in the thoracic duct lymph fluid in the LC group increased significantly, and peaked 2 h after the administration. In addition, bLF was not detected in the plasma of the LC group. Immunohistochemical analysis clearly showed anti-bLF positive particles in the epithelial cells of the apical villi. The striated border and baso-lateral membrane were also bLF positive. These results suggest that intraduodenally infused bLF is transported into the blood circulation via the lymphatic pathway, not via portal circulation in adult rats.

Oral Administration of Lactoferrin Inhibits Inflammation and Nociception in Rat Adjuvant-Induced Arthritis

Lactoferrin (LF) is a ubiquitous protein which exists in milk, plasma, synovial fluids, cerebrospinal fluid and other biological fluids. LF is also well known as a natural immunomodulator. Recently, we found that bovine milk-derived LF (BLF) produced micro-opioid receptor-mediated analgesia. In this study, we examined whether oral administration of BLF causes anti-nociceptive and anti-inflammatory effects, and also whether it modulates LPS-induced TNF-alpha and IL-10 production in rat model of rheumatoid arthritis (RA), rat adjuvant arthritis. BLF was administrated once daily, starting 3 hr before (preventive experiment) or 19 days after (therapeutic experiment) adjuvant injection. In both experiments, BLF suppressed the development of arthritis and the hyperalgesia in the adjuvant-injected paw. The single-administered BLF produced a dose-dependent analgesia, which was reversed by naloxone, in the adjuvant arthritis rats. Both repeated and single administration of BLF suppressed TNF-alpha production and increased IL-10 production in the LPS-stimulated adjuvant arthritis rats. These results suggest that orally administered BLF has both preventive and therapeutic effects on the development of adjuvant-induced inflammation and pain. Moreover, the immunomodulatory properties of BLF, such as down-regulation of TNF-alpha and up-regulation of IL-10, could be beneficial in the treatment of RA. Thus, we concluded that LF can be safely used as a natural drug for RA patients suffering from joint pain.

Lactoferrin enhances opioid-mediated analgesia via nitric oxide in the rat spinal cord

Lactoferrin (LF) is a multifunctional protein that is found in milk, neutrophils, and other biological fluids, and its receptors have also been identified in the central nervous system. Recently, we found that bovine milk-derived LF (BLF) produced analgesia via a mu-opioid receptor-mediated response in the spinal cord. However, the precise mechanism of this analgesic effect remains unclear. In this study, spinally applied BLF produced analgesia that was reversed by coadministration with a nitric oxide (NO) synthase inhibitor, NG-nitro-l-arginine methyl ester, during phases 1 and 2 in the formalin test. Spinal coadministration of a mu-opioid receptor agonist, morphine, with a subeffective dose of BLF produced a much more highly potentiated analgesia than that produced by morphine alone during phases 1 and 2 in the formalin test. This potentiated analgesia by morphine with BLF was reversed by a mu-opioid receptor antagonist, d-Phe-Cys-Tyr-d-Trp-Orn-Thr-NH2, or by NG-nitro-l-arginine methyl ester. In the tail-flick test, continuous spinal infusion of morphine via an osmotic minipump over 6 days resulted in development of tolerance by day 4, but no tolerance of BLF was observed throughout the experiment. These results suggest that BLF acts as an enhancer of the spinal opioidergic system via an NO-mediated mechanism.

Opioid mediated suppressive effect of milk-derived lactoferrin on distress induced by maternal separation in rat pups

The present study assessed the effects of bovine milk-derived lactoferrin (bLf) on distress activities induced by maternal separation in 5- to 18-day-old rat pups. The rat pups were injected with BSA (100 mg/kg, i.p.; control) or bLf (100 mg/kg, i.p.) 30 min before the behavioral test. Distress activity was estimated by means of recording body movements or ultrasonic vocalizations (USVs). After 5 min of maternal separation, bLf significantly (P<0.01) suppressed body movements, particularly in the 10-day-old pups. This suppressive effect of bLf was reversed by pretreatment with naloxone, CTOP, and norBNI at doses of 0.1-1 mg/kg. Additionally, USVs were also suppressed by bLf, which was reversed by pretreatment with naloxone. Inhibition of nitric oxide synthase (NOS) with nitro-L-arginine methyl ester (L-NAME) dose dependently (3-10 mg/kg) suppressed separation-induced USV production in 10-day-old pups. Interestingly, the suppressive effect of bLf was completely reversed by pretreatment with a low dose (1 mg/kg) of L-NAME, which did not affect the USVs with single application. These findings demonstrate that milk-derived bLf suppresses distress induced by maternal separation via an opioid-mediated mechanism. Furthermore, bLf possibly activates NOS, and an elevated nitric oxide may cause some modification of the opioid system.

Persorption of bovine lactoferrin from the intestinal lumen into the systemic circulation via the portal vein and the mesenteric lymphatics in growing pigs

The absorption and the transportation of intestinally administrated bovine lactoferrin (LF) were immunohistochemically and physiochemically investigated in the small intestine of growing pigs. At the apical halves of the small intestinal villi, bovine LF was absorbed by transcytosis as small vesicles through villous columnar epithelial cells. The presence of bovine LF-positive membranes of transcytotic vesicles suggests that the absorption was mediated by LF-binding factors on the epithelial cell membranes. Almost all of the absorbed bovine LF was demonstrated to be transported via the lymphatics and the portal vein into the systemic circulation. The LF-concentration in systemic circulation was significantly higher at 1 hr following intestinal administration of bovine LF. Bovine LF-positive lymphocytes also were transferred into the systemic circulation from intestine via the lymphatics and the portal vein.

Novel function of bovine milk-derived lactoferrin on antinociception mediated by mu-opioid receptor in the rat spinal cord

Lactoferrin (LF) is a multifunctional protein that is found in milk, neutrophils, and other biological fluids. Although LF and the LF receptor have been identified in the central nervous system (CNS), the physiological role of LF remains unknown. We found that bovine milk-derived LF (BLF) reduces nociception in various pain models, as shown by the formalin test, hot plate test, and acetic acid writhing test in rats. Intraperitoneal (i.p.) administration of BLF significantly inhibited nociception in these pain models. These antinociceptive effects were also confirmed in BLF-fed rats. The antinociceptive effects of BLF were blocked by naloxone treatment, even though prostaglandin E(2) (PGE(2)) production in the ascites fluid that accumulated during the writhing test was not affected by BLF. Intrathecal (i.t.) application of BLF caused marked antinociceptive effects that were reversed by co-administration of a specific mu-opioid receptor antagonist, D-Phe-Cys-Tyr-D-Trp-Orn-Thr-NH(2) (CTOP), or by naloxone during the formalin test. We conclude that LF possesses mu-opioid receptor-mediated antinociceptive activity in the spinal cord.

Receptor-Mediated Transport of Lactoferrin into the Cerebrospinal Fluid via Plasma in Young Calves

Milk, especially colostrum, contains different kinds of macromolecules abundantly, such as immunoglobulin G (IgG), lactoferrin (Lf), transferrin (Tf), and growth factors. These are essential for the development and maintenance of health, which greatly depends on the absorption and transportation of macromolecules to the target organs. To evaluate the macromolecular transport, and concentrations in plasma and cerebrospinal fluid (CSF), colostrum was fed to newborn calves followed by milk and milk replacer, and maintained up to the 4th week under farm conditions. Plasma and CSF were collected at different times, and were analyzed for Lf, Tf, IgG and iron concentrations. Lf, Tf and IgG concentrations were steeply increased in plasma and CSF after colostrum feeding, and fluctuating patterns were observed during the experiments. Furthermore, intraduodenal administration of bovine Lf alone in young calf experiments revealed that the Lf concentration reached a peak at 4 hr, and was 7 and 4 times higher than preadministration in plasma and CSF, respectively. To explore the transport mechanism of Lf into CSF in young calves, epithelial membranes of the choroid plexus were prepared and a binding assay for Lf receptors (Lf-R) was carried out with 125I-Lf. The saturation kinetics revealed that the Bmax of epithelial membranes was 26.15 nmol/mg protein with a Kd of 0.11 microM, which also showed that Lf-R is saturable and specific. Scatchard plot transformation showed the presence of a single type of Lf-R in the choroid plexus. These results suggest that Lf is transported into the CSF through receptor mediated transcytosis in young calves, and that Lf may play an important role(s) in brain function.

Characteristic transfer of colostrum-derived biologically active substances into cerebrospinal fluid via blood in natural suckling neonatal pigs

The characteristic transfer of colostral components into cerebrospinal fluid (CSF) via serum after natural suckling has been studied by sodium dodecyl sulphate (SDS) electrophoresis, two-dimensional electrophoresis, immunoblot and enzyme linked immunosorbent assay methods in non-suckling pigs. Total protein concentrations in the serum increased immediately after first suckling, reached a peak value at 12 h, corresponding to a 2.3-fold compared with pre-suckling level. The protein concentration in CSF also increased and reached peak value at 6 h corresponding to 1.6-fold compared with presuckling level. IgG in serum not detected before suckling, increased steeply after suckling, IgG, IgM and IgA transported into the serum were observed in completely intact form by immunoblot method. The IgG transported into serum was quickly transferred into CSF after natural suckling in contrast to the case of bovine IgG. Serum concentration of transferrin was maintained at high level before suckling and was not changed by suckling. Transferrin also detected in CSF was not changed by suckling. Bovine lactoferrin (Lf) administered into the intestinal lumen was transported into serum (0.01%) and also detected in CSF after 6 h as undegraded form (3.1%). Thus, homologous IgG and bovine Lf are transported into CSF, suggesting that the transport of macromolecules into CSF is selective in neonatal pigs.

Transport of colostral macromolecules into the cerebrospinal fluid via plasma in newborn calves

The objective of this study was to investigate the transfer of bovine colostral macromolecules especially the lactoferrin (Lf), transferrin (Tf), immunoglobulin G (IgG), and epidermal growth factor (EGF) from the gastrointestinal tract to the cerebrospinal fluid (CSF) via systemic circulation in newborn calves. Cannulae were placed into the jugular vein and cisterna magna to collect blood and CSF, respectively at various time points. The colostrum, plasma, and CSF were analyzed by ELISA, SDS-PAGE, two-dimensional PAGE, and Western blotting. The concentration of total protein, Lf, Tf, and IgG in plasma averaged 47 mg, 204 ng, 101 microg and 15 microg/ml before colostrum feeding and increased to the peak values of 64 mg, 2413 ng, 820 microg, and 4608 microg/ml 8 h after feeding, respectively. Before colostral feeding CSF, total protein, Lf, Tf, and IgG averaged 0.44 mg, 10.3 ng, 0.31 microg, and 0.11 microg/ml, but peak values after feeding averaged 2.0 mg, 173 ng, 71 microg and 72 microg/ml after 10 h, respectively. Immunologically, six EGF-positive protein bands were detected in colostrum as well as in three bands higher density in plasma and CSF after colostral feeding. This study revealed that the colostral macromolecules were not only absorbed into the systemic circulation, but also some of them including Lf, Tf, IgG, and EGF-like proteins were transported into the CSF in a time-dependent manner through blood-CSF or blood-brain barrier of the newborn calves.

Lactoferrin protects neonatal rats from gut-related systemic infection

Lactoferrin is a milk protein that reportedly protects infants from gut-related, systemic infection. Proof for this concept is limited and was addressed during in vivo and in vitro studies. Neonatal rats pretreated orally with recombinant human lactoferrin (rh-LF) had less bacteremia and lower disease severity scores (P < 0.001) after intestinal infection with Escherichia coli. Control animals had 1,000-fold more colony-forming units of E. coli per milliliter of blood than treated animals (P < 0.001). Liver cultures from control animals had a twofold increase in bacterial counts compared with cultures from rh-LF-treated pups (P < 0.02). Oral therapy with rh-LF + FeSO(4) did not alter the protective effect. In vitro studies confirmed that rh-LF interacted with the infecting bacterium and rat macrophages. An in vitro assay showed that rh-LF did not kill E. coli, but a combination of rh-LF + lysozyme was microbicidal. In vitro studies showed that rat macrophages released escalating amounts of nitric oxide and tumor necrosis factor-alpha when stimulated with increasing concentrations of rh-LF. The in vitro studies suggest that rh-LF may act with other "natural peptide antibiotics" or may prime macrophages to kill E. coli in vivo.

Effects of pasteurization of colostrum on subsequent serum lactoferrin concentration and neutrophil superoxide production in calves

OBJECTIVE

To determine the effects of pasteurization of colostrum on serum lactoferrin concentration and neutrophil oxidative function by comparing values from calves given pasteurized (76 C, 15 minutes) colostrum versus calves given fresh frozen colostrum.

ANIMALS

8 Holstein bull calves were used to study the effects of pasteurization of colostrum on the absorption of lactoferrin and neutrophil oxidative burst. Three additional calves were used to study the effect of exogenous lactoferrin on neutrophil oxidative burst.

METHODS

Calves were fed fresh frozen or heat pasteurized colostrum (76 C for 15 minutes) via esophageal feeder within 4 hours of birth. Neutrophils were isolated from whole blood samples. Neutrophil oxidative burst was induced by phorbol ester (300 ng/ml) stimulation of cells (1 X 10(6) cells) at 37 C. Serum lactoferrin concentrations were compared, using immunoblot analysis. Serum IgG concentrations were determined by radial immunoassay. Comparisons were made between the use of the 2 types of colostrum in calves by measuring subsequent serum IgG and lactoferrin concentrations and neutrophil superoxide production.

RESULTS

Serum IgG and lactoferrin concentrations increased more in calves receiving fresh frozen colostrum. Neutrophil superoxide production was higher in neutrophils prepared from calves receiving fresh frozen colostrum. Colostral lactoferrin addition to neutrophil incubations resulted in increased oxidative burst.

CONCLUSIONS AND CLINICAL RELEVANCE

Compared with calves given fresh frozen colostrum, calves given pasteurized colostrum had decreased serum IgG and lactoferrin concentrations and neutrophil superoxide production 24 hours after administration. These results suggest that pasteurizing bovine colostrum at 76 C for 15 minutes has substantial effects on passive transfer of proteins and neutrophil function.

Characteristic transport of lactoferrin from the intestinal lumen into the bile via the blood in piglets

Lactoferrin is a major iron-binding protein in milk from several species, such as humans, monkeys, mice and sows. Using neonatal and weaner piglets, the characteristic transfer of lactoferrin from intestinal lumen into bile via the circulation was investigated. Bovine lactoferrin (1 or 3 g/kg body weight) was infused into the stomach through a polyethylene tube or into the duodenum through a duodenal catheter over 5 min. Peripheral blood and bile samples were collected after the infusion. Lactoferrin absorbed into plasma and bile were assayed quantitatively by double-antibody enzyme-linked immunosorbent assay, and homogeneity of bovine lactoferrin in plasma and bile was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting methods. Morphological investigation was carried out according to the peroxidase anti-peroxidase method. Following oral administration in neonatal pigs, bovine lactoferrin appeared in the blood circulation and reached a peak level after 2 h. It was confirmed immunohistochemically that lactoferrin was transported by endocytosis via the epithelial cells. Lactoferrin absorbed into the blood was also detected in the bile and reached a peak value 12 h after oral administration. Transportation of lactoferrin from the intestinal lumen into the bile via the bloodstream was also observed in weaner piglets. Lactoferrin transported into plasma and bile was confirmed to be the same substance as administrated lactoferrin by electrophoresis and immunoblotting methods. Lactoferrin transported into bile was re-absorbed into the blood in neonatal pigs. These results demonstrate that lactoferrin contained in milk is transported into the circulation from the intestinal lumen and excreted into the bile, suggesting the possibility of entero-hepatic circulation of lactoferrin in neonatal pigs.