Tear Lactoferrin Research Articles

Comparison of hydrogel contact lens patients with and without the symptom of dryness

Two groups of hydrogel contact lens-wearing patients were compared. One group of 32 patients had the symptom of drying while wearing their contact lenses, whereas the second group of 26 patients were comfortable with the lenses with no feeling of dryness. The patients were asked to fill out a modified McMonnies questionnaire, and the tear prism height, tear film breakup time, fluorescein and rose bengal staining, and lactoferrin level were measured. There were marked differences in the patients' responses to the questions concerning their sensitivity to smoke and environmental irritants, dryness of other mucous membranes, irritation on awakening, and the use of rewetting drops. The patients with the symptoms of drying indicated more problems in all these areas. There was a significant decrease in tear film breakup time and lactoferrin levels and more fluorescein staining in the symptomatic group, but no measurable difference in tear prism height between the groups.

Tear function parameters in keratoconjunctivitis sicca with and without the association of Sjögren's syndrome.

In a group of patients with keratoconjunctivitis sicca (KCS) associated with Sjögren's syndrome (SJ) a significant decrease in tear fluid lactoferrin concentration and tear film break-up time was demonstrated in comparison with a matched group in which KCS was not associated with any systemic disease. The Schirmer values were also lower in the SJ of patients and these differences almost reached statistical significance. None of these parameters in itself appeared to be of any clinical value to differentiate between KCS that was or was not associated with SJ. The combination of the tear fluid lactoferrin concentration, the Schirmer I test values and the tear film break-up time, however, provide a basis for differential diagnosis that is clinically of some value.

Lactoferrin and serum albumin in the conjunctival fluid of eyes operated for senile cataract

The concentrations of serum albumin (SA) in the conjunctival fluid were measured in 25 patients before surgery and in the post-operative period following cataract extraction. We found a significant increase in mean tear fluid SA concentration on the first post-operative day. The SA concentration remained high during the first 3 pre-operative levels. No correlation between the post-operative concentration profile of tear fluid SA and earlier findings of the tear lactoferrin (LF) profile of the same group of patients (Jensen et al. 1985) could be shown, although a trend towards an inverse relationship was apparent from the graphs. Pre-operatively, we found a significant positive correlation between age and concentration of SA in the conjunctival fluid (P less than 0.05) which might be interpreted as an increase in leakage from conjunctival vessels with age. This would, at least partly, explain the decreasing LF concentration with age (Jensen et al. 1986; McGill et al. 1984). It is concluded that transudate/exudate from the conjunctival vessels, represented by the change in the SA concentration in the conjunctival fluid, might be responsible for an initial post-operatively reduced concentration of LF and possibly other lacrimal gland proteins.

Guinea pig tears contain lactoferrin and transferrin

The ironbinding protein lactoferrin is one of the main proteins in human tears. Until now no animal models are available to investigate the exact role of this protein on the ocular surface. We have therefore started investigations concerning the presence of ironbinding proteins in various laboratory animals. In this report the presence of lactoferrin and transferrin in guinea pig tears was investigated using an iron-binding assay, Ouchterlony immunodiffusion, ELISA and immunoblotting techniques. Guinea pig tears contain a weak ironbinding activity, which is markedly lower than that observed in human tears. Lactoferrin and transferrin were identified using the fact that guinea pig lactoferrin reacts with monoclonal and polyclonal anti human lactoferrin antibodies and that guinea pig serum transferrin reacts with an anti rabbit transferrin serum. SDS-PAGE and immunoblotting showed that, guinea pig lactoferrin and transferrin have a similar molecular weight of approximately 75 kD, which is however, definitely smaller than that of human lactoferrin and transferrin (80 kD). The amount of lactoferrin in guinea pig tears, measured in an ELISA using anti human lactoferrin antisera, was very low (equalling 600 mg/ml of human lactoferrin immunoreactivity). Transferrin in guinea pig tears was measured with an ELISA in 10 guinea pigs and resulted in a mean concentration of 22.3 micrograms/ml. The species comparisons performed until now indicate that human tears remain unique in their high content of lactoferrin.

The concentration of lactoferrin in tears of normals and of diabetics.

The tear lactoferrin content and the tear secretion rate was determined in 105 normal subjects (age range: 15-93 years) and 21 diabetic patients (age 21-78 years). Tear sampling was performed using glass capillaries and the lactoferrin concentration in tears was tested employing an enzyme-linked immunosorbent assay. Tear secretion rate was measured using standardized Halberg filter paper placed in the inferior fornix for 5 min. The lactoferrin level of normal tears showed a significant inverse correlation with age, the mean value of the 8th decade (0.81 mg/ml) constituting only about half the value of the lactoferrin level found in the 3rd decade (1.48 mg/ml). The tear secretion rate also displayed a significant decrease with age, but no correlation could be demonstrated between the tear secretion rate and lactoferrin concentration. No difference was found in lactoferrin level between men and women. We were not able to demonstrate any correlation between lactoferrin content of tears and the duration of diabetes in the 21 diabetic subjects, and there was no difference between the level of lactoferrin in normal tears compared to the concentration in diabetic tears. No difference was found between the tear secretion rate in normals and in diabetics.

Bacteriology and tear protein profiles of the dry eye.

The concentrations of tear lysozyme, lactoferrin, ceruloplasmin, IgA, and IgG have been estimated in patients with dry eyes at the same time as semiquantitative bacterial culture was performed of the conjunctivae and lids. Staphylococcal isolations were quantified and biotyped. There was no increased conjunctival colonisation by any particular biotype of Staphylococcus aureus or Staph. epidermidis, and similar numbers of conjunctivae were sterile as in controls (33%); neither were any pathogens such as pneumococci or haemophili isolated. We consider that the conjunctiva of the dry eye, without the lacrimal secretion components of lysozyme and lactoferrin, has an alternative protective antibacterial mechanism which is derived from serum proteins via chronically inflamed vessels.

The concentration of lactoferrin in tears during post-operative ocular inflammation.

Tear concentration of lactoferrin (LF) was measured by an ELISA technique and followed in 25 patients undergoing cataract surgery. The pre-operative concentration of LF in tears was 773 +/- 60 micrograms/ml (+/- SE) (range: 407-1514 micrograms/ml). On the first day following surgery, there was a significant decrease in tear LF concentration to 377 +/- 45 micrograms/ml followed by a gradual return to the initial value during a post-operative observation period of twelve days. There was an inverse linear relationship between the LF concentration and the tear secretion rate measured by a modified Schirmer I test (1 min) suggesting a constant LF secretion rate by the tear glands. The contribution of LF from neutrophils to the tear fluid seems to be of minor importance. Since LF has known antibacterial and anti-inflammatory effects, our results may contribute to a further understanding of the microbial vulnerability or resistance of the eye following surgical procedures.

Separation of human tear proteins by high performance liquid chromatography.

The optimal conditions for separating human tear proteins by high performance liquid chromatography (HPLC) using a Waters I-125 gel filtration column were investigated. Several elution buffers were tested including phosphate buffer alone and phosphate buffer to which varying amounts of NaCl or 0.1% Tween was added. The combination of phosphate buffer (pH 5.28), 0.5 M NaCl and 0.1% Tween gave the best resolution and a recovery of 90% of the proteins applied. Tear lactoferrin was shown to adhere to the column packing when the molarity of the elution buffer was not high enough. Using optimal conditions, the tear proteins IgA, lactoferrin and lysozyme were identified in distinct peaks after a preparative HPLC run. When used in combination with Schirmer strips as a tear sampling method, HPLC was shown to be a rapid, simple and reproducible way of investigating the composition of tear proteins.

Lactoferrin levels in normal human tears.

Using commercially available reagents we developed an enzyme-linked immunosorbent assay to measure lactoferrin in normal human tears. Tears obtained from 38 normal human subjects contained a mean lactoferrin content of 2.2 mg/ml (g/l). No differences in the mean level of lactoferrin were found when tears were collected by either Schirmer tear strips or by glass capillaries after short tear gas stimulation. Tear lactoferrin levels were not influenced by age or sex of the subjects investigated in this study. We found that lactoferrin represents approximately 25% by weight of the total tear proteins.

Conjunctivitis Sicca-Reply

<h3>In Reply.</h3> —I appreciate Dr Lambert's concern for data analysis. While I did not go into detail regarding the diagnosis of conjunctivitis sicca in my nine cases, I stated that all had Schirmer test values of less than 10 mm of wetting in five minutes. I also referred to their subjective symptoms and their response to a tear substitute. Were this the central theme of my study, I would have included such aspects as tear osmolarity and lactoferrin content studies recently reported by Farris^1,2with rose bengal stain, lysozyme content, and electrophoresis (older criteria), which Dr Lamberts does not mention. From his own article, to which he does allude, I might also include the dimensions and qualities of the tear strip as visualized at the slit lamp. Yet the latter, as described by the authors themselves, are even more subjective and variable than are the Schirmer test readings. With

Inhibition of the classical complement system by tear lactoferrin

Inhibition of the classical complement system by tear lactoferrin

A polyacrylamide-gel electrophoretic study of human tear proteins.

The protein composition of normal and pathological tears was studied by polyacrylamide-gel (disc) electrophoresis. Polyacrylamide-gel electrophoresis was shown to detect at least 14 fractions in 2-10 microliters of native tears. A comparison was made between the protein composition of normal tears and serum. The most characteristic bands in the tear-protein pattern were identified by parallel electrophoresis of tears, serum, human milk and purified egg-white lysozyme. The identified fractions were specific tear prealbumin, serum albumin, transferrin, lactoferrin and lysozyme. An unidentified major tear-protein component was also described. The tear-protein pattern was divided into six zones: (1) prealbumin zone; (2) post-albumin zone; (3) post-transferrin zone; (4) macroglobulin zone; (5) basic globulin zone; (6) prelactoferrin zone. A significant rise in the level of serum albumin and transferrin was demonstrated in tears from cases of acute catarrhal conjunctivitis. The optimal circumstances were discussed under which major and minor tear components and basic and acidic tear proteins can be determined simultaneously. Polyacrylamide-gel electrophoresis is recommended as a useful method to study the various diseases of the anterior segment of the eye.

Inhibition of hemolytic complement activity by lactoferrin in tears

As previously reported human tears contain an anticomplementary factor capable of inhibiting total hemolytic complement activity in human tears. In order to elucidate the nature of this anticomplementary effect several techniques were used. Partial isolation of the anticomplementary factor in human tears by sucrose gradient ultracentrifugation and immunization of rabbits with the isolated fraction yielded an antiserum with a specificity for lactoferrin. The sedimentation profile of a major part of the anticomplementary effect in human tears coincided with that of lactoferrin. Further evidence that the anticomplementary activity was associated with lactoferrin was obtained by isolating lactoferrin from human tears by anion exchange chromatography. This resulted in an isolated fraction, containing anticomplementary activity, showing one band on SDS-polyacrylamide gel electrophoresis and which was identified as lactoferrin by immunochemical means. At a concentration of 4·8 μg/ml, isolated tear lactoferrin, could inhibit 50% of the hemolytic complement activity present in diluted human serum (containing 1·5 total hemolytic complement units). These findings thus show that a major part of the anticomplementary effect present in human tears is associated with lactoferrin. Ths suggests that lactoferrin, besides its known antibacterial properties may also have an anti-inflammatory function in preventing activation of the complement system on the external surface of the eye.

Basal and Reflex Human Tear Analysis: II. Chemical Analysis: Lactoferrin and Lysozyme

Unstimulated basal tears and stimulated tears were collected from normal controls, keratoconjunctivitis sicca (KCS) patients, and contact lens (CL) wearers. Basal tear volume (Periopaper®) and reflex tear volume (Schirmer Strip®) were measured and tears eluted from their respective strip with a TMED-acetic acid buffer. Lactoferrin and lysozyme concentrations were measured in the eluates. Concentration of lysozyme in basal tears was: 65 ± 43 mg% in normals; 44 ± 26 mg% in KCS, and 81 ± 50 mg% in CL wearers. Concentration of lysozyme in reflex tears was: 160 ± 73 mg% in normals, 74 ± 41 mg% in KCS, and 186 ± 83 mg% in CL wearers. Concentration of lactoferrin in basal tears was 137 ± 102 mg% in normals, 154 ± 82 mg% in KCS, and 157 ± 80 mg% in CL wearers. Concentrations of lactoferrin in reflex tears was: 327 ± 187 mg% in normals; 171 ± 69 mg% in KCS, and 302 ± 160 mg% in CL wearers. The lactoferrin concentration in all tear samples was consistently higher (1.6–3.5 times) than lysozyme. In basal tears, lactoferrin concentrations were not significantly different in the three groups. In reflex tears, however, lactoferrin was significantly lower in KCS than normal or CL wearers. The concentration of lysozyme in both basal and reflex tears was significantly lower in the KCS when compared to normal or CL wearers. Lysozyme and lactoferrin concentrations in both basal and reflex tears were similar in CL wearers and normal controls. The sampling and elution of basal and reflex tears as described appears to be a feasible technique for analysis of lysozyme-and lactoferrin concentrations by the electroimmunodiffusion technique and has potential diagnostic value.

Lactoferrin in Human Ocular Tissues

The main lacrimal gland and accessory lacrimal tissue from seven autopsy cases, lacrimal biopsy specimens from three patients, and conjunctival biopsy specimens from ten patients were examined for lactoferrin by an immunohistologic technique. Lactoferrin was identified and localized to acinar epithelial cells of both main and accessory lacrimal tissue. Lactoferrin was not found in conjunctival tissue except within conjunctival neutrophils. Other possible sources of human tear lactoferrin were considered, but we concluded from our data that the primary source of lactoferrin in normal human tears is the acinar epithelium of the main and accessory lacrimal glands.

PH of the contents of the duodenal bulb in relation to duodenal ulcer.

<h3>BACKGROUND/AIMS</h3> Decreased tear volume in patients with chronic hepatitis C has been reported in the literature. Lactoferrin is abundantly present in human tears, the main source of which is the acini of the lacrimal glands. In this study tear lactoferrin levels were measured to investigate the dry eye condition of patients with chronic hepatitis C. <h3>METHODS</h3> Lactoferrin in tears/fluid was measured by a radial immunodiffusion assay in 42 patients with chronic hepatitis C. The rate of lacrimal secretion was determined by the cotton thread test. Rose bengal staining of the ocular surface was also performed. <h3>RESULTS</h3> Only three patients out of 42 complained of dry eye sensation and, in 31 patients, six showed positive results on the rose bengal staining test of the ocular surface. The lactoferrin concentration of tear fluid in the chronic hepatitis C group (1.42 (SD 0.56) mg/ml) was significantly lower than in the control group (1.90 (0.62) mg/ml; p &lt;0.00048). The cotton thread test results in the chronic hepatitis C group (12.9 (5.5) mm) were significantly lower than in the control group (17.9 (5.3) mm; p&lt;0.00048). Also, in the chronic hepatitis C group, tear lactoferrin concentration correlated with the results of the cotton thread test (<i>r</i> = 0.35, p&lt;0.05). <h3>CONCLUSION</h3> Chronic hepatitis C patients showed both decreased tear volume, and decreased tear lactoferrin concentration. These findings suggest that there may be dysfunction of the lacrimal glands in patients with chronic hepatitis C, which may account for the mild dry eye.