Abstract:
Disclosed is a product and method for transplanting biological fluids into a host animal (including humans) that have been collected from donor animals. These biological fluids have been purified and processed so that they are acellular, sterile, pathogen free, and a form that can be stored for considerable periods of time without degradation. In one embodiment, synovial fluid is harvested from a large number of donors to produce the transplantation compound. Donor fluid is collected from a number of joints per animal, and initially screened for obvious abnormalities (clarity, color, viscosity . . . etc.) and accepted or rejected on a joint-by-joint basis at the time of collection. The collected fluid is frozen in the field. Once in a laboratory setting, the fluid is warmed and spun down in a centrifuge. The supernate is collected, filtered, and mixed in large batches while the permeate is discarded. The supernate is re-frozen, lyophilized (freeze-dried) to form a cake and packaged as an individual dose under vacuum. The product is sterile, stable, has a long shelf life and can be readily reconstituted and injected into a joint.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 10/727,893, entitled “Method Of Treating Mammalian Joint Maladies By Biological Fluid Transplantation,” filed Dec. 3, 2003 by Charles P. Meader, which was based upon and claims the benefit of U.S. Provisional Patent Application Ser. No. 60/430,999, filed Dec. 3, 2002, by Charles P. Meader and Paul V. Christofferson, entitled “Method for Treating Mammalian Joint Maladies by Biological Fluid Transplantation,” both of which are hereby specifically incorporated herein by reference for all that they disclose and teach. 
    
    
     BACKGROUND OF THE INVENTION 
     a. Field of the Invention 
     The present invention relates generally to treating maladies in mammalian joints and more specifically to transplanting biological fluids in mammalian joints for therapeutic benefit. 
     b. Description of the Background 
     Various methods of treating joint maladies have been attempted dating back to the origins of human and veterinary medicine. Most of these treatments fall under the realm of either medicines or modalities. Medicinal treatments typically involve the adding of some type of chemical agent, either topically or systemically to the affected patient. Modality treatments such as heat, ice, electrical stimulation, physical manipulation or the like are performed on the affected joint or surrounding tissue. The modality treatments seek to induce a physiological change in the targeted area that stimulates or promotes healing. The transplantation of biological fluids from one part of a single host to another, in order to affect a therapeutic state, has been attempted for at least 30 years. 
     For example, synovial fluid has been harvested from “good” joints in horses and transplanted into “bad” joints of the same animal with limited success. One of the primary drawbacks in using this technique is that it assists one joint at the expense of others. By using the synovial fluid from donor animals to transplant into the affected joint of an ailing recipient, a new series of challenges come into play. Transmittal of pathogens, disease and infection to the recipient, as well as various negative immunological responses of the host to donor tissue can arise. If any cellular component of the donor animal fluid or other contaminant is exchanged, infection and/or rejection issues can arise that can be more detrimental to the animal than the malady that was initially being treated. The use of donor fluids that have been screened for pathogens and cellular components has been contemplated with limited success mainly due to the volatility and shelf life of the biological fluids. Synovial fluid, for example, begins to degrade within hours of being removed from the host and conventional preservation techniques have not been able to suspend this deterioration in a manner that is conducive to practical use. A method is therefore needed to preserve synovial fluids for extended periods to allow these fluids to be stored and transplanted in other animals at a later time. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the disadvantages and limitations of the prior art by providing a method of transplanting biological fluids into a host animal (including humans) that have been collected from donor animals. These biological fluids have been purified and processed so that they are acellular, sterile, pathogen free, and a form that can be stored for considerable periods of time without degradation. In one embodiment, synovial fluid is harvested from a large number of donors to produce the transplantation compound. Donor fluid is collected from a number of joints per animal, and initially screened for obvious abnormalities (clarity, color, viscosity . . . etc.) and accepted or rejected on a joint-by-joint basis at the time of collection. The collected fluid is frozen in the field. Once in a laboratory setting, the fluid is warmed and spun down in a centrifuge. The supernate is collected, filtered, and mixed in large batches while the permeate is discarded. The supernate is re-frozen, lyophilized (freeze-dried) to form a cake and packaged as an individual dose under vacuum. The product is sterile, stable, has a long shelf life and can be readily reconstituted and injected into a joint. 
     The present invention may therefore comprise a solid that can be reconstituted to provide a replacement fluid for use in treating a joint malady of an animal made by the process comprising: collecting synovial from donor animals; removing impurities, cellular and pathogenic components from the synovial fluid to create a purified synovial fluid; and, lyophilizing the purified synovial fluid. 
     The present invention may also comprise a method of treating a joint malady of an animal by intraarticularly injecting a purified synovial fluid in the joint space of the animal, the purified synovial fluid made by the process of: collecting synovial from donor animals; removing impurities, cellular and pathogenic components from the synovial fluid to create a purified synovial fluid; lyophilizing the purified synovial fluid; and, reconstituting the purified synovial fluid to approximately its original volume. 
     The present invention may also comprise a method of manufacturing a concentrated solid that can be reconstituted to provide a replacement fluid for use in treating a joint malady of an animal comprising: collecting synovial from donor animals, removing impurities, cellular and pathogenic components from said synovial fluid; lyophilizing said purified synovial fluid to form a solid; and, packaging said lyophilized solid in a manner so as to provide said lyophilized solid that is reconstitutable to serve as an injectable replacement fluid. 
     Numerous benefits may be afforded by the disclosed embodiments and include the ability to treat a variety of joint maladies in a manner which does not rely on systemic oral or injected medications to affect a systemic response to a particular localized problem. In many circumstances of joint disease and disorder, the synovial fluid is adversely affected. Whether it is a case of degradation to the existing make-up of the fluid, a contamination or dilution from blood, plasma or other body fluid, or an insufficient amount of synovia present within the joint capsule, all of these adversities may be improved by the addition or transplantation of high-quality synovial fluid. The present invention provides a product that can act as this replacement, with significant longevity and effectiveness and can be provided in a sterile and convenient manner. The freeze-dried synovial fluid cake may also be reconstituted or mixed with various other therapeutic agents, before being injected into the joint capsule, further enhancing the salutary benefits of the treatment. 
     The present invention has been tested on equine donors and recipients with good success. The equine archetype is a particularly relevant animal model for this technology because there is a significant market for joint therapy in sporting horses dumpers and racers), with a readily available source of equine fluid donors found in slaughterhouses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, 
         FIG. 1  is a drawing showing the equine skeletal anatomy displaying typical harvest sites for donor synovial fluid. 
         FIG. 2  is a table showing the constituents of synovial fluid vs. blood plasma. 
         FIG. 3  is a flowchart showing steps for harvesting synovial fluid for later processing from the joints of horses. 
         FIG. 4  is a flowchart showing steps for processing, lyophilizing and packaging synovial fluid in a pyrogen free and aseptic manner. 
         FIG. 5  is a flowchart showing detailed steps for lyophilizing synovial fluid in a pyrogen free and aseptic manner. 
         FIG. 6  is a product insert for Nor-Syn-E® a single dose, lyophilized replacement for normal equine synovial fluid. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While this invention is susceptible to embodiment in many different forms, there is shown in the drawings and will be described herein in detail specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not to be limited to the specific embodiments described. 
       FIG. 1  is drawing showing the equine skeletal anatomy displaying typical harvest sites for donor synovial fluid. Typically, but not by way of exclusion, both radio carpal (knee) and humeral radial (elbow) joints on the forelimbs, and both tibial tarsal (hock) and femoral tibial (stifle) joints are harvested. These joints are the most accessible and yield the most fluid at approximately 5 cc of synovial fluid per joint. 
       FIG. 2  is a table showing the constituents of synovial fluid versus blood plasma. Synovia is the fluid present in certain joints that are consequently termed “synovial.” Similar fluid is present in bursae and in synovial sheaths. Synovial fluid, the chief functions of which are joint lubrication and nourishment of the articular cartilage, is a sticky viscous fluid, often with an egg white consistency. It is usually slightly alkaline and ranges from colorless to deep yellow. The color and viscosity vary with species of animal and type of joint. For example, fluid from a large joint is usually less viscous and cellular than from small joints. Synovial fluid viscosity also varies inversely with temperature, being more viscous at lower temperatures. 
     Synovial fluid is an ultrafiltrate of plasma. Most of the synovial fluid&#39;s ions and molecules are present in plasma. The principal constituent that distinguishes synovial fluid from other dialysate is the glycoprotein mucin. This component of synovial fluid has been identified as hyaluranon or hyaluronic acid (HA), a non-sulfated mucopolysaccharide that is produced by the synovial cells lining the membranous portion of the joint cavity. Hyaluronic acid is responsible for the viscosity of synovial fluid and is present at about 0.5 mg/ml in normal joint fluid. Synovial fluid is usually slightly alkaline, having a pH of approximately 7.6. Hyaluronie acid is normally bound to a protein to form what is called Hyaluronate protein. The protein, moiety is an important lubrication factor (HA is linked to about 2% protein). 
     As further outlined in  FIG. 2 , the other constituents of synovial fluid are those that are normally present in blood plasma. Synovial fluid also normally contains a few cells, mostly mononuclear, derived from the lining tissue (the cells appear to be more numerous in fluid from smaller joints.) Many pathological processes, infections, rheumatic disorders, autoimmune disorders, and neoplasms affect the synovial membranes, and they generally alter the cellular content of the fluid. 
     The viscosity of synovial fluid is due almost entirely to the hyaluronic acid, the viscosity of which increases exponentially with increasing concentrations. Solutions of more than 1 percent may form gels. The viscosity of synovial fluid decreases to that of water if the hyaluronic acid is removed by precipitation with enzymes, if it is hydrolyzed enzymatically, or if its polymerization is destroyed by enzymes or by physical processes. Hyaluronic acid is normally bound to protein to form what is termed hyaluronate protein. The glycoprotein lubricin is made by certain synovial cells and lubricates the articular surfaces of the joint. Further detail regarding synovial fluid and their associated membranes can be found in Appendix A which is herein incorporated by reference. 
       FIG. 3  is a flowchart showing steps for harvesting synovial fluid for later processing  300  from the joints of horses. Once a suitable donor has been selected, a particular joint is selected at step  302  for harvesting. In horses, this is typically a knee or elbow joint on the forelimb or a hock or stifle joint on the hind limb. The joint capsule is then penetrated at step  304  with a 1½-inch, 18-gauge needle attached to a 12 cc sterile syringe. The contents of the joint capsule are then aspirated into the syringe at step  306  and the contents are visually inspected for acceptability at step  308 . Three main constituents are used to determine the acceptability criteria at step  332  for the donor fluid. The color of the fluid should be clear to pale yellow, and should be clear with and contain no signs of blood, tissue, cells, debris or the like. The viscosity of the fluid should roughly be in the range of 5 to 1 at the lower limit, to 10 to 1 at the upper limit. Any sign of unacceptability at step  310  with regards to this criteria results in immediately discarding the fluid at step  314  and starting the process over by selecting a new joint at step  302 . 
     If the acceptance criteria are met, and the fluid is deemed acceptable at step  312 , the entire content of the joint capsule is aspirated and the needle is withdrawn from the joint at step  316 . The fluid is then transferred from the syringe and placed into a commercially available container for biological fluid collection such as a Vacutainer™ tube. Typically, a 10 cc Vacutainer tube containing 1 cc of 100 mg of Gentomicin (0.9%) as a preservative is used. It is then determined if the Vacutainer has is at capacity at step  320 . If that Vacutainer is not full at step  322 , the process is repeated at step  326  by selecting the next joint at step  302 . If the Vacutainer is at capacity at step  324 , it is then packed in dry ice for preservation during short-term storage and shipping at step  328 . The Vacutainers are removed from the dry ice shipping and placed in a freezer at −80° F. at step  330  for storage. 
       FIG. 4  is a flowchart showing steps for processing, lyophilizing and packaging synovial fluid in a pyrogen free and aseptic manner  400 . Once the synovial fluid is collected from the donor animals, it is processed by initially warming the samples to 4° C. at step  402 . The Vacutainers containing the synovial fluid are spun down by centrifuge at step  404  until all the permeate is separated in the bottom of the Vacutainer tube. The supernate is then collected at step  406  and the permeate (pellicle) is discarded at step  408 . At this point, the contents of each Vacutainer are sampled and are Wrights stain tested to determine quality and suitability at step  410 . Other quality control tests can be performed at this time at step  412 , and may include sterility testing for bacteria, molds and fungi. Samples are also pulled to determine protein content using a refractometer at step  414 . The supernate is consolidated  416  and mechanically filtered through a series of successively tighter pore size filters, starting at approximately 8 μm and going down to 0.45 μm at step  418 . The filtered supernate is then collected and placed in ½ or one liter batches. These batches are returned to the freezer for storage at −80° F. at step  420 . The processed synovial fluid is then ready for lyophilization and packaging at step  422 . 
       FIG. 5  is a flowchart showing detailed steps for lyophilizing synovial fluid in a pyrogen free and aseptic manner  500 . The filtered supernate that has been processed and stored at −80° F. is thawed at step  502 . Batches of 100 ml of synovial fluid are then gently stirred using a stir bar while 100 ml of the stabilizer formulation is slowly added at step  504 . The stabilizer formulation comprises: 5 g Mannitol (5%), 5 g Glycine (5%) and qs 100 Ml using distilled water. An alternate stabilizer formulation may comprise: 5 g Mannitol (5%), 5 g Glycine (5%), 0.1 g Polysorbate 80 (0.1%) and qs 100 ml using distilled water. Additional alternate stabilizer formulations have been contemplated and may be used as suitable. Further detail regarding the study lyophilization formulations can be found in Appendix B, which is herein incorporated by reference. 
     The mixture is continuously stirred until uniform color and viscosity appear at step  506  (less than 5 minutes.) An 11 ml quantity of synovial fluid and stabilizer formulation mixture is placed in each of 20 ml vials and transferred to the lyophilizer  508 . One thermocouple is placed in randomly selected vials of solution, taking care to place of the thermocouple in the center, and touching the bottom of the vial at step  510 . The vials are frozen for a minimum of six hours at a shelf temperature of −45° C. at step  512 . The pressure is then reduced in the lyophilization chamber to less than 50 microns Hg at step  514 . The shelf temperature is controlled at −35° C. and held for 72 hours at step  516 . At this point the shelf temperature is increased to 0° C. and held for 12 hours at step  518  which is followed by an increase in the shelf temperature to 25° C. and held for an additional 12 hours at step  520 . With the lyophilization completed, stoppers are inserted in the vials while under full vacuum at step  522 . The final product of lyophilized synovial fluid is fully packaged, pathogen and pyrogen free. This product is a material that is a dense concentrate typically presented in a solid, semi-solid or cake like or powder form. This material is now ready for reconstitution as high-quality synovial fluid, with a shelf life of greater than 1 year when stored under refrigeration at 35° to 45° F. 
       FIG. 6  is a product insert for Nor-Syn-E® a single dose, lyophilized replacement for normal equine synovial fluid. 
     The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art. 
     Appendix A 
     Synovial membrane is a vascular connective tissue that lines the inner surface of the capsule but does not cover the bearing surfaces. It consists of formed elements such as cells and fibers, together with intercellular material called matrix or ground substance. The connective tissue cells (synoviocytes) that are adjacent to the joint cavity are grouped together in one to three layers to form a relatively smooth surface from which a variable number of folds—villi—and fat pads project onto the joint cavity. Immediately subjacent to these surface cells is a capillary network. Scanning electron microscopy demonstrates characteristic undulations of the surface and separation of the synoviocytes. Two types of synoviocytes (A&amp;B) have been described in a number of species. These types differ in their ultrastructure, and may represent different states of activity of the same cell type. The tissue immediately subjacent to these surface cells and capillary network may be fibrous, areolar, or fatty. It varies in thickness and contains fibroblasts, macrophages, mast cells, and fat cells as well as blood and lymphatic vessels and a few nerve fibers. If a synovial membrane is removed, a new synovial membrane may form from this underlying tissue or from the joint capsule. 
     The ground substance or matrix of any connective tissue when examined under the light microscope seems to be an amorphous substance. All ground substances contain complex compounds of high molecular weight, including mucopolysaccharides, a sulfate free compound termed hyaluronic acid. All mucopolysaccharides are complex asymmetric long-chain molecules that form viscous sols or even gels. They are attacked by a variety of enzymes usually called hyaluronidases. It is thought that basic units, probably disaccharides, are formed elsewhere and brought to connective tissue by the blood stream. In joints, synoviocytes synthesize these units into hyaluronic acid, probably chiefly by polymerization, that is, by a linking together of the basic units. This is an active energy-requiring process. It is not yet known, however, whether type A cells alone, or type B, or both, are responsible. 
     Appendix B 
     The Influence of Formulation Composition on the Stability of Freeze-Dried Equine Synovial Fluid 
     Summary 
     A study was carried out to compare the solid-state stability profile of five different formulations of equine synovial fluid at −20° C., and −80° C., and 5° C. over a period of eight weeks. A mucin clot test was used as a measure of product quality. Although the variability of the mucin clot test was a major limitation of this study, formulations containing 10% Mannitol and 10% Maltodextrin provided the best results as measured by clot quality over the course of the study. Polysorbate 80 and human serum albumin seems to offer no advantage. A formulation containing Mannitol and Glycine was nearly equivalent to the formulations containing Maltodextrin. The stability data did not support a clear conclusion as to whether there is a significant loss of activity during storage at either 5° C. or −20° C. Surprisingly, there appears to be a loss of clot quality with time during storage at −80° C. There is significant loss of activity during storage of the reconstituted product at room temperature. 
     Objective 
     The purpose of this experiment was to compare the solid-state stability of five different formulations of equine synovial fluid over an eight-week interval at temperatures of −80° C., −20° C., and 5° C. in order to identify the most promising formulation for further study. 
     Experimental 
     Materials 
     Equine synovial fluid (Lot 121399) was used as received from Dr. Paul Christofferson of Equine Bio-Tech Inc. Maltodextrin (M500) was from Grain Processing Corporation, Muscatine, IA. Mannitol and Glycine were analytical grade material from Mallinckrodt (Paris, KY). Polyexyethylene sorbitan monooleate (Tween 80) was from Sigma Scientific (St. Louis, MO). Human serum albumin was a gift from Bayer Corporation (Berkeley, CA). 
     Methods 
     Preparation of Formulations 
     The stabilizer systems used in this study were as follows: 
     Formulation # 1: 
     
         
         
           
             10% Mannitol 
             10% Maltodextrin
 
Formulation # 2:
 
             10% Mannitol 
             10% Maltodextrin 
             0.1% Polysorbate 80
 
Formulation # 3:
 
             10% Mannitol 
             0.1% Polysorbate 80
 
Formulation # 4:
 
             10% Mannitol 
             0.1% Polysorbate 80 
             2% serum albumin
 
Formulation # 5:
 
             5% Mannitol 
             5% Glycine 
             0.1% Polysorbate 80 
           
         
       
    
     Each stabilizer solution was mixed with an equal volume of synovial fluid, and 2 ml was filled into 5 ml vials. The product was freeze-dried by freezing overnight at −40° C., followed by drying for 48 hours at a shelf temperature of −35° C. and 12 hours at 25° C. 
     Product vials were stored at 5° C., −20° C., and −80° C. (control.) Each formulation was tested about every two weeks for a total of ten weeks. The freeze-dried solid was reconstituted with 1 ml of water prior to testing. 
     Mucin Clot Test 
     The reconstituted formulation (100 μL) was added, using an Eppendorf pipette, to 1 mL 10% v/v acetic acid in a 2 cm radius petri dish. The test is based on visual assessment of the morphology of the resulting mucin clot using criteria established by Ropes and Bauer (1953). The clot was compared with pictures from the above reference rating the clot as a, b, c, or d:
         a. A tight clump surrounded by a clear solution   b. A soft mass not as tightly clotted as category “a”   c. A clot that is dispersed over a relatively large area with no distinct shape. Some discrete pieces are dispersed within the clot area   d. A few ropy strands in a cloudy solution. No distinct clot is formed       

     Results and Discussion 
     Mucin clot test data from the stability study are shown in Tables I-III for 5° C., −20° C., and −80° C., respectively. Duplicate results are recorded where available. A second test was carried out using reconstituted solid from the same vial. The subjective nature of the mucin clot, test is a major limitation of the study, as can be seen from the data in these tables. Every attempt was made to use consistent technique; that is, attempting to expel the reconstituted solid at a constant rate into the acetic acid solution and placing the tip of the pipette just below the surface of the liquid. 
     Based on the SOC data (Table I), formulations 1 and 2 appear to be the best, even though clots as poor as “d” were observed at times during the stability study. Formulation 5 may be as good as formulations 1 and 2 however, considering the variability of the test method. Formulations 3 and 4 yielded, the poorest clots initially, and they remained the poorest clots throughout the study. The variability in the data do not allow a definitive conclusion as to whether there is a loss in the quality of the clot during storage at 5° C. 
     Table II summarizes the −20 C. data. Again, formulations 1 and 2 appeared to result in the best clots initially as well as at the end of the study, but clot quality as low as “d” was observed for formulation 1 and “c”-“d” for formulation 2. Formulation 5 was next, and formulations 3 and 4 were the worst. The data in Table II do not allow a clear conclusion as to whether there is a significant decrease in clot quality during storage of the freeze-dried solid. 
     Storage at −80° C. would not be expected to result in loss of activity during storage. However, as shown in Table III, all of the formulations showed poorer clots at the end of the study than at the beginning. The reason for this is not known at present. 
     Reconstituted stability data are summarized in Table IV, where reconstituted solids from the last time interval were examined within minutes after reconstitution and again after 19 hours at room temperature. There is a significant loss of clot quality, although the test method used does not allow a quantitative assessment. The data do support the conclusion that the product should be used as soon as practical after reconstitution. 
     CONCLUSIONS 
     Despite the limitations of the test method, the stability data at 5° C. and −20 C. support the conclusion that formulations 1 and 2 provide the best product, although no firm conclusions can be drawn as to whether there is a significant loss of activity during storage. Polysorbate 80 seems to offer no particular advantage, since it was present in both “goody’ and “bad” trial batches. Likewise, human serum albumin does not appear to offer any advantage. Maltodextrin does seem to help, but formulations 1 and 2 were only marginally better than formulation 5, which contains Mannitol, Glycine, and Polysorbate 80. 
     Reconstituted stability data show that the product should be used as soon as practical after reconstitution.