重组人乳铁蛋白对缺铁性贫血大鼠铁营养状况的改善作用

目的研究从转基因牛乳中分离纯化的重组人乳铁蛋白(rhLf)对缺铁性贫血(IDA)大鼠铁营养状况是否具有改善作用。方法雌性断乳Wistar大鼠喂饲低铁饲料建立IDA模型,按造模结束时Hb和体重随机分为6组,即模型对照组(A组),0.375、0.75和2.25g/kg BW rhLf组(B、C、D组),0.011g/kg BW乳酸亚铁组(E组),0.375g/kg BW rhLf与0.011g/kg BW乳酸亚铁联合补充组(F组),每组12只,每天一次性灌胃给予受试物,连续8周。检测指标包括动物一般情况、体重变化、Hb和RBC、游离原卟啉(FEP)、血清铁(SI)、总铁结合力(TIBC)、运铁蛋白饱和度(TS)、血清铁蛋白(SF)、血清Cu和血清Zn。结果与A组相比,E、F组大鼠一般情况明显改善,体重、RBC、Hb、SI、TS和SF显著增加,FEP、TIBC和血清Zn降低,机体铁营养状态基本恢复正常;D组上述指标较A组同样有显著性差异,但改善程度低于E、F组,动物仍处于缺铁状态;C组RBC较A组显著增加,FEP和血清Zn显著降低,其他指标无差异;B组仅血清Zn显著低于A组,其他指标无差异。E、F两组比较时,F组SI、TS和SF均显著高于E组,TIBC低于E组。结论单纯补充rhLf对IDA大鼠铁营养状况具有一定程度的改善作用,但较乳酸亚铁弱;乳酸亚铁与rhLf联合应用时改善机体铁营养状况的作用强于单纯补充乳酸亚铁或rhLf,同时可减轻亚铁离子导致的不良反应。     

Bovine lactoferrin digested with human gastrointestinal enzymes inhibits replication of human echovirus 5 in cell culture

Many infant formulas are enriched with lactoferrin (Lf) because of its claimed beneficial effects on health. Native bovine Lf (bLf) is known to inhibit in vitro replication of human enteroviruses, a group of pathogenic viruses that replicate in the gut as their primary infection site. On the basis of a model digestion and human gastrointestinal enzymes, we hypothesized that bLf could retain its antiviral properties against enterovirus in the gastrointestinal tract, either as an intact protein or through bioactive peptide fragments released by digestive enzymes. To test our hypothesis, bLf was digested with human gastric juice and duodenal juice in a 2-step in vitro digestion model. Two gastric pH levels and reduction conditions were used to simulate physiological conditions in adults and infants. The antiviral activity of native bLf and of the digested fractions was studied on echovirus 5 in vitro, using various assay conditions, addressing several mechanisms for replication inhibition. Both native and digested bLf fractions revealed a significant inhibitory effect, when added before or simultaneously with the virus onto the cells. Furthermore, a significant stronger sustained antiviral effect was observed when bLf was fully digested in the gastric phase with fast pH reduction to 2.5, compared with native bLf, suggesting the release of antiviral peptides from bLf during the human digestion process. In conclusion, this study demonstrates that bLf may have a role in the prevention of human gastrointestinal virus infection under physiological conditions and that food containing bLf may protect against infection in vivo.     

Lactoferrin and the newborn: current perspectives

Neonatal sepsis and necrotizing enterocolitis (NEC) are associated with significant mortality and morbidity. Inflammation secondary to sepsis and NEC increases morbidity, especially those related to the lung, brain and eye. Therapeutic strategies that target inflammation and decrease the emergence of antibiotic resistance are urgently needed. Lactoferrin (Lf) is a multifunctional protein that modulates inflammation, cell growth and differentiation and has broad antimicrobial activity. Studies evaluating the efficacy and safety of Lf in the prevention of neonatal sepsis and NEC are currently in progress, and one completed study shows significant promise. In this article, the functions of this multifunctional molecule and current clinical evidence for its use in the newborn are reviewed. Lf prophylaxis and therapy may have a significant impact in improving clinical outcomes of vulnerable preterm neonates.     

Faecal calprotectin and lactoferrin values during irradiation of prostate cancer correlate with chronic radiation proctitis: Results of a prospective study

Objective. Acute proctitis and chronic radiation proctitis are relevant complications of pelvic radiation. The purpose of this study was to investigate two markers of gut inflammation during and after irradiation for prostate cancer to evaluate a correlation between acute and chronic proctitis. Material and methods. Two patient groups were analysed. In group 1, stool samples from 20 patients were collected before therapy, every week during therapy, at the end of therapy, and 13 and 27 months after therapy. Group 2 comprised 47 patients who had undergone irradiation 40 months earlier. Toxicity was determined by common toxicity criteria (CTC) and the LENT soma scale. Calprotectin and lactoferrin values were determined by ELISA. Results. In group 1, acute values for both faecal markers were significantly correlated with chronic proctitis symptoms and all patients with chronic toxicity had acute proctitis symptoms with elevated faecal values. In group 2, where stool samples were solely collected 40 months after irradiation, the Pearson square test showed both a significant correlation between calprotectin and lactoferrin values and toxicity after 40 months. Conclusions. Within a group of 19 patients followed for two years after irradiation for prostate cancer, and 47 patients tested 40 months after irradiation, increased faecal values of calprotectin and lactoferrin were significantly correlated with the occurrence of chronic proctitis. This observation should be confirmed in an expanded study.     

Lactoferrin in the gingival crevice as a marker of polymorphonuclear leucocytes in periodontal diseases

Abstract This study examined lactoferrin (LF) levels in gingival crevicular fluid (GCF) and set out to test the hypothesis that LF could act as a marker of crevicular polymorphonuclear leucocytes (PMN), Therefore, 2 experiments were conducted: (a) to quantify total LF (ng/30 s sample) in GCF; (b) to correlate LF levels (ng/μl) and PMN numbers (PMNs/μl) in gingival crevicular washings (GCW). GCF was collected from 71 sites in a total of 22 patients. These sites were classified on the basis of clinical indices of gingivitis (GI) and pocket depth (PD) into three clinical groups:‘healthy’, ‘gingivitis’ and ‘periodontitis’. GCWs were obtained from an additional 63 sites in 21 patients. LF in GCF and GCWs was assayed by a sandwich ELISA. Total leucocyte and differential counts were performed on the GCWs. GCF LF (ng/30 s) correlated positively with GI (r=0.418, p<0.001), PD (r=0.415, p<0.001) and GCF volume (r=0.624, p<0.001). Gingivitis (n=21) and periodontitis sites (n=24) demonstrated significantly higher (p<0.05) total GCF LF than healthy (n=26) sites. In GCWs LF (ng/μl) showed stronger correlations with clinical indices (GI: r=0.452, PD: r=0.513, p<0.001) than did PMN numbers (PMNs/μl) (GI: r=0.279, PD: r=0.388, p<0.05). LF correlated strongly with PMNs in GCWs (r=0.531, p<0.001) and provides a simple and effective marker of crevicular PMN numbers.     

Chemotactic Activity of LTB4 in Man

An improved skin window chamber technique has been developed and used for a quantitative study of the chemotactic effect of leukotriene B4 (LTB4). LTB4 (0.5 microM) was exposed to a skin window on the forearm of eight healthy volunteers, while phosphate buffered saline served as control in a skin window on the other forearm. Skin window exudates and samples of blood draining the skin window areas were collected after 1, 2, 4, 8, and 24 h. The samples were quantitated for the different types of leukocytes as well as the intra- and extracellular concentration of the eosinophilic cationic protein and lactoferrin as markers of eosinophil and neutrophil granulocytes. A significantly increased migration of neutrophil granulocytes into the skin window chamber containing LTB4 was found from the 2nd to the 8th hour after the initial LTB4 exposure. The eosinophils reached a significant peak at the 4th hour. The rise in the actual number of eosinophil cells did not reach significance, whereas measurements of the eosinophilic cationic protein in the cellular fraction of the exudate exhibited a significant increase as a reflection of the number of eosinophils. This highlights the potential clinical value of eosinophilic cationic protein measurements to reveal eosinophilia instead of the traditional eosinophil counts. Extracellular eosinophilic cationic protein and lactoferrin did not change significantly in the LTB4-exposed skin window, implying that LTB4 does not activate the eosinophils and neutrophils to exocytosis of their enzymes. The present in vivo results support the concept of LTB4 being a potent chemoattractant to neutrophil and less so to eosinophil granulocytes in humans, a chemoattractant that recruits the leukocytes but does not seem to activate them.     

In vivo release of the antimicrobial peptide hLF1‐11 from calcium phosphate cement

We studied the release of human lactoferrin 1‐11 (hLF1‐11), a potent antimicrobial peptide, in an animal model. Calcium phosphate cement with 50 mg/g hLF1‐11 was injected into the femoral canal of 12 rabbits. One, 3, and 7 days later, four animals were terminated, and the femora excised. Sections of bone and cement were removed for histological analysis. We used liquid chromatography‐mass spectrometry/mass spectrometry for semiquantitative determination of the hLF1‐11 concentration. Blood samples were drawn for leukocyte count and differentiation to identify a potential immunomodulating effect of hLF1‐11. After an initial burst release, the hLF1‐11 concentration in cement and bone decreased steadily. This in vivo release profile is consistent with earlier in vitro studies. Tissue ingrowth into the cement, without signs of inflammation or necrosis, was observed. Leukocytosis or a shift in leukocyte differentiation did not occur. The carrier released over 99% of the hLF1‐11, resulting in peak concentrations at the cement–bone interface. This indicates that hLF1‐11 could become a valuable prophylactic agent in osteomyelitis treatment. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:531–538, 2008     

The relation of different inflammatory cell types to the various parenchymal components of rejecting kidney allografts

Histochemical and immunoperoxidase techniques were used to characterize the spatial relationships of various inflammatory cell types to the different transplant structures in human renal allograft rejection. T lymphocytes were identified by acid α-naphthyl acetate esterase (ANAE) staining, plasma cells by intracyto-plasmic immunoglobulin, mononuclear phagocytes by intracytoplasmic 'dispersed' ANAE reaction and/or lysozyme staining and granulocytes by intra-cellular lactoferrin. In the two cases of acute rejection the infiltrate around the blood vessels consisted mainly of lymphocytes, whereas the infiltrate around the tubules and within the glomerular tufts consisted mainly of mononuclear phagocytes. In acute rejection only a few plasma cells and granulocytes were seen. In the single case of chronic rejection studied, the lymphocytes were no longer concentrated exclusively around the blood vessels, but diffusely distributed throughout the kidney parenchyma. The different distribution of various inflammatory cells may reflect differences in the functions of these cell types in graft destruction.     

Sorrento studies of diet and fecal flora in the newborn

The fecal flora of a breast-fed baby is very different from that of a bottle-fed baby. This paper reviews five previous studies, performed at this hospital concerning the effect of various dietary components (whey proteins, casein, lactoferrin, iron, nucleotides) on the fecal flora. The babies received either breast milk or one of the test formulas from birth. Fecal samples were examined by quantitative microbiological methods at 4 and 14 days and at various intervals thereafter. By 14 days differences in the fecal flora were established. Among breast-fed babies bifidobacteria, lactobacilli and staphylococci were predominant organisms, whereas in the formula-fed babies the predominant organisms were enterococci, coliforms, and Bacteroides. A whey-based formula without bovine lactoferrin, iron or nucleotides gave a flora a little closer to but still remote from the breast-fed one. Despite extensive modification of cow's milk in the manufacture of a modern infant formula, the fecal flora of bottle-fed babies remains substantially different from that of breast-fed babies.     

Serum Myeloperoxidase and Lactoferrin in Neutropenia

Radioimmunosorbent assays for determination of serum content of the neutrophil proteins myeloperoxidase and lactoferrin are described. Serial studies were performed in patients with neutropenia. In 2 cases of cyclic neutropenia the myeloperoxidase level showed slight variations within the normal range during the cycle while lactoferrin displayed a clear correlation with neutrophil counts. In 1 case with persistent agranulocytosis myeloperoxidase was normal but lactoferrin was extremely low. During the regeneration phase of drug-induced neutropenia neutrophil counts and serum lactoferrin increased in a parallel fashion. Since serum myeloperoxidase was normal during profounded neutropenia it is suggested to derive primarily from myeloperoxidase-rich granulopoietic precursor cells of the marrow. Serum lactoferrin on the other hand seems to derive from leakage of more mature granulopoietic cells of blood and marrow. Studies of neutrophil proteins of serum may aid in evaluation of neutropenic patients.