Assessing unintended effects of a mammary-specific transgene at the whole animal level in host and non-target animals

Risk assessment in transgenic plants is intrinsically different than that for transgenic animals; however both require the verification of proper transgene function and in conjunction, an estimate of any unintended effects caused by expression of the transgene. This work was designed to gather data regarding methodologies to detect pleiotropic effects at the whole animal level using a line of transgenic goats that produce the antimicrobial protein human lysozyme (hLZ) in their milk with the goal of using the milk to treat childhood diarrhea. Metabolomics was used to determine the serum metabolite profile of both the host (lactating does) and non-target organism (kid goats raised on control or hLZ milk) prior to weaning (60 days), at weaning (90 days) and 1 month post-weaning (120 days). In addition, intestinal histology of the kid goats was also carried out. Histological analysis of intestinal segments of the pre-weaning group revealed significantly wider duodenal villi (p = 0.014) and significantly longer villi (p = 0.028) and deeper crypts (p = 0.030) in the ileum of kid goats consuming hLZ milk. Serum metabolomics was capable of detecting differences over time but revealed no significant differences in metabolites between control and hLZ fed kids after correction for false discovery rate. Serum metabolomics of control or hLZ lactating does showed only one significant difference in an unknown metabolite (q = 0.0422). The results as a whole indicate that consumption of hLZ milk results in positive or insignificant intestinal morphology and metabolic changes. This work contributes to the establishment of the safety and durability of the hLZ mammary-specific transgene.

Consuming transgenic goats' milk containing the antimicrobial protein lysozyme helps resolve diarrhea in young pigs

Childhood diarrhea is a significant problem in many developing countries and E. coli is a main causative agent of diarrhea in young children. Lysozyme is an antimicrobial protein highly expressed in human milk, but not ruminant milk, and is thought to help protect breastfeeding children against diarrheal diseases. We hypothesized that consumption of milk from transgenic goats which produce human lysozyme (hLZ-milk) in their milk would accelerate recovery from bacterial-induced diarrhea. Young pigs were used as a model for children and infected with enterotoxigenic E. coli. Once clinical signs of diarrhea developed, pigs were fed hLZ-milk or non-transgenic control goat milk three times a day for two days. Clinical observations and complete blood counts (CBC) were performed. Animals were euthanized and samples collected to assess differences in histology, cytokine expression and bacterial translocation into the mesenteric lymph node. Pigs consuming hLZ-milk recovered from clinical signs of infection faster than pigs consuming control milk, with significantly improved fecal consistency (p = 0.0190) and activity level (p = 0.0350). The CBC analysis showed circulating monocytes (p = 0.0413), neutrophils (p = 0.0219), and lymphocytes (p = 0.0222) returned faster to pre-infection proportions in hLZ-milk fed pigs, while control-fed pigs had significantly higher hematocrit (p = 0.027), indicating continuing dehydration. In the ileum, pigs fed hLZ-milk had significantly lower expression of pro-inflammatory cytokine IL-8 (p = 0.0271), longer intestinal villi (p<0.0001), deeper crypts (p = 0.0053), and a thinner lamina propria (p = 0.0004). These data demonstrate that consumption of hLZ-milk helped pigs recover from infection faster, making hLZ-milk an effective treatment of E. coli-induced diarrhea.

Dissecting the role of milk components on gut microbiota composition

The composition of human milk is tailored to contribute to the development of the gastrointestinal (GI) tract of newborns and infants. Importantly, human milk contains the antimicrobial compounds lysozyme and lactoferrin that are thought to contribute to the formation of a health-promoting microbiota. As these protective factors are lacking in the milk of dairy animals, we genetically engineered goats expressing human lysozyme in their milk and have recently reported a new animal model to dissect out the role of milk components on gut microbiota formation. Using the pig as a more human-relevant animal model, we demonstrated that consumption of lysozyme-rich milk enriched the abundance of bacteria associated with GI health and decreased those associated with disease, much like human milk. This work demonstrated that the pig is a valid animal model for gut microbiome studies on the effects of dietary components on microbiota composition, host-microbe interactions and state of the intestine.

TRANSGENIC ANIMALS IN AGRICULTURE

The first reports on the effects of human growth hormone in transgenic mice, engendered speculation about how genetic engineering could be applied to improve livestock for use in agriculture. However, 30 years later this promise has yet to be realised as there are no GE animals approved for food consumption anywhere in the world. Initial work mostly either concentrated on the production of animals (sheep and swine) with deregulated growth hormone (GH) genes or represented work to improve our understanding of gene constructs for the control of gene expression. Although a variety of GH transgenic lines of livestock were successfully produced, most had compromised health and were not suitable for further development. However, several lines of transgenic farm animals and fish could be potentially useful genotypes for use in production agriculture, including GH pigs, phytase pigs, lysozyme goats, lactoferrin cows, and lactalbumin pigs. To date, none of these lines have yet been approved for human consumption and thus have not made it into production. Many of these lines have been placed in frozen storage or have been lost and would need to be redeveloped. The reasons for this are varied and include simply retirement of the developer, through to insufficient funds, pressure from anti-biotechnology activists, lack of a regulatory process, public opposition, or lack of a perceived need by industry. The combination of these factors has led to a virtual cessation of research and development of transgenic animals for use in agriculture in North America, Europe, and Australia, early leaders in developing this technology, and the emergence of programs in places such as Brazil and China, where the next generation of GE animals for agriculture will be developed. However, recent advances in the methodology to produce transgenic animals, such as the use of transposons or site-directed nucleases such as TALENs, may lead to renewed efforts to develop targeted GE animals for use in agriculture.

Short communication: Identification of coagulase-negative staphylococcus species from goat milk with the API Staph identification test and with transfer RNA-intergenic spacer PCR combined with capillary electrophoresis

Coagulase-negative staphylococci (CNS) are the most commonly isolated bacteria from goat milk, but they have often been identified with phenotypic methods, which may have resulted in misclassification. The aims of this paper were to assess the amount of misclassification of a phenotypic test for identifying CNS species from goat milk compared with transfer RNA intergenic spacer PCR (tDNA-PCR) followed by capillary electrophoresis, and to apply the tDNA-PCR technique on different capillary electrophoresis equipment. Milk samples were collected from 416 does in 5 Californian dairy goat herds on 3 occasions during lactation. In total, 219 CNS isolates were identified at the species level with tDNA-PCR and subjected to the API 20 Staph identification test kit (API Staph; bioMérieux, Durham, NC). If the same species was isolated multiple times from the same udder gland, only the first isolate was used for further analyses, resulting in 115 unique CNS isolates. According to the tDNA-PCR test, the most prevalent CNS species were Staphylococcus epidermidis, Staphylococcus caprae, and Staphylococcus simulans. Typeability with API staph was low (72%). Although the API Staph test was capable of identifying the majority of Staph. epidermidis and Staph. caprae isolates, sensitivity for identification of Staph. simulans was low. The true positive fraction was high for the 3 most prevalent species. It was concluded that the overall performance of API Staph in differentiating CNS species from goat milk was moderate to low, mainly because of the low typeability, and that genotypic methods such as tDNA-PCR are preferred.

Vignettes from the field of mathematical biology: the application of mathematics to biology and medicine

The application of mathematical models in biology and medicine has a long history. From the sparse number of papers in the first half of the twentieth century with a few scientists working in the field it has become vast with thousands of active researchers. We give a brief, and far from definitive history, of how some parts of the field have developed and how the type of research has changed. We describe in more detail just two examples of specific models which are directly related to real biological problems, namely animal coat patterns and the growth and image enhancement of glioblastoma brain tumours.

Glioblastoma brain tumours: estimating the time from brain tumour initiation and resolution of a patient survival anomaly after similar treatment protocols

A practical mathematical model for glioblastomas (brain tumours), which incorporates the two key parameters of tumour growth, namely the cancer cell diffusion and the cell proliferation rate, has been shown to be clinically useful and predictive. Previous studies explain why multifocal recurrence is inevitable and show how various treatment scenarios have been incorporated in the model. In most tumours, it is not known when the cancer started. Based on patient in vivo parameters, obtained from two brain scans, it is shown how to estimate the time, after initial detection, when the tumour started. This is an input of potential importance in any future controlled clinical study of any connection between cell phone radiation and brain tumour incidence. It is also used to estimate more accurately survival times from detection. Finally, based on patient parameters, the solution of the model equation of the tumour growth helps to explain why certain patients live longer than others after similar treatment protocols specifically surgical resection (removal) and irradiation.

Growth hormone enhances arachidonic acid metabolites in a growth hormone transgenic mouse

In a transgenic growth hormone (GH) mouse model, highly elevated GH increases overall growth and decreases adipose depots while low or moderate circulating GH enhances adipose deposition with differential effects on body growth. Using this model, the effects of low, moderate, and high chronic GH on fatty acid composition were determined for adipose and hepatic tissue and the metabolites of 20:4n-6 (arachidonic acid) were characterized to identify metabolic targets of action of elevated GH. The products of Δ-9 desaturase in hepatic, but not adipose, tissue were reduced in response to elevated GH. Proportional to the level of circulating GH, the products of Δ-5 and Δ-6 were increased in both adipose and hepatic tissue for the omega-6 lipids (e.g., 20:4n-6), while only the hepatic tissues showed an increase for omega-3 lipids (e.g., 22:6n-3). The eicosanoids, PGE₂ and 12-HETE, were elevated with high GH but circulating thromboxane was not. Hepatic PTGS1 and 2 (COX1 and COX 2), SOD1, and FADS2 (Δ-6 desaturase) mRNAs were increased with elevated GH while FAS mRNA was reduced; SCD1 (stearoyl-coenzyme A desaturase) and SCD2 mRNA did not significantly differ. The present study showed that GH influences the net flux through various aspects of lipid metabolism and especially the desaturase metabolic processes. The combination of altered metabolism and tissue specificity suggest that the regulation of membrane composition and its effects on signaling pathways, including the production and actions of eicosanoids, can be mediated by the GH regulatory axis.

Lysozyme transgenic goats' milk positively impacts intestinal cytokine expression and morphology

In addition to its well-recognized antimicrobial properties, lysozyme can also modulate the inflammatory response. This ability may be particularly important in the gastrointestinal tract where inappropriate inflammatory reactions can damage the intestinal epithelium, leading to significant health problems. The consumption of milk from transgenic goats producing human lysozyme (hLZ) in their milk therefore has the potential to positively impact intestinal health. In order to investigate the effect of hLZ-containing milk on the inflammatory response, young pigs were fed pasteurized milk from hLZ or non-transgenic control goats and quantitative real-time PCR was performed to assess local expression of TNF-α, IL-8, and TGF-β1 in the small intestine. Histological changes were also investigated, specifically looking at villi width, length, crypt depth, and lamina propria thickness along with cell counts for intraepithelial lymphocytes and goblet cells. Significantly higher expression of anti-inflammatory cytokine TGF-β1 was seen in the ileum of pigs fed pasteurized milk containing hLZ (P = 0.0478), along with an increase in intraepithelial lymphocytes (P = 0.0255), and decrease in lamina propria thickness in the duodenum (P = 0.0001). Based on these results we conclude that consuming pasteurized milk containing hLZ does not induce an inflammatory response and improves the health of the small intestine in pigs.

Reverse-translational biomarker validation of Abnormal Repetitive Behaviors in mice: an illustration of the 4P's modeling approach

The NIMH's new strategic plan, with its emphasis on the "4P's" (Prediction, Pre-emption, Personalization, and Populations) and biomarker-based medicine requires a radical shift in animal modeling methodology. In particular 4P's models will be non-determinant (i.e. disease severity will depend on secondary environmental and genetic factors); and validated by reverse-translation of animal homologues to human biomarkers. A powerful consequence of the biomarker approach is that different closely related disorders have a unique fingerprint of biomarkers. Animals can be validated as a highly specific model of a single disorder by matching this 'fingerprint'; or as a model of a symptom seen in multiple disorders by matching common biomarkers. Here we illustrate this approach with two Abnormal Repetitive Behaviors (ARBs) in mice: stereotypies and barbering (hair pulling). We developed animal versions of the neuropsychological biomarkers that distinguish human ARBs, and tested the fingerprint of the different mouse ARBs. As predicted, the two mouse ARBs were associated with different biomarkers. Both barbering and stereotypy could be discounted as models of OCD (even though they are widely used as such), due to the absence of limbic biomarkers which are characteristic of OCD and hence are necessary for a valid model. Conversely barbering matched the fingerprint of trichotillomania (i.e. selective deficits in set-shifting), suggesting it may be a highly specific model of this disorder. In contrast stereotypies were correlated only with a biomarker (deficits in response shifting) correlated with stereotypies in multiple disorders, suggesting that animal stereotypies model stereotypies in multiple disorders.

Gene silencing in bovine zygotes: siRNA transfection versus microinjection

The aim of this study was to compare gene silencing in bovine zygotes when small interfering RNAs (siRNAs) were introduced into bovine zygotes by microinjection or lipid-based transfection. In Experiment 1, E-cadherin siRNA was injected at 100 or 375 µM and compared with PBS-injected and non-injected controls. Embryos were then cultured in vitro for 7 days and periodically assessed for development. For transfection, zona-free zygotes were incubated in transfection medium with siRNA for 1 h at 39°C and then cultured to Day 7. Injection of PBS or 375 µM E-cadherin siRNA resulted in a decrease in the number of embryos reaching the 8-cell stage (51.5% and 45.5%) or the blastocyst stage (39.0 and 32.5%) compared with non-injected controls (62.9 and 45.0%, respectively; P < 0.05). Messenger RNA abundance was suppressed by 36 and 46% when siRNA targeting E-cadherin was injected at 100 and 375 µM, respectively, compared with controls (P < 0.05). Transfection with 100 nM E-cadherin siRNA decreased development to the 8-cell stage (20.3 versus 53.0%) and blastocyst stage (7.2 versus 18.2%) compared with controls (P < 0.05). Messenger RNA relative abundance was not different between controls (non-transfected or transfected with GAPDH or scrambled siRNA). However, transfection of zygotes with 100 and 200 nM E-cadherin siRNA led to a 72 and 38% reduction, respectively, in E-cadherin mRNA relative abundance in Day 7 blastocysts compared with controls (P < 0.05).

Precision genetics for complex objectives in animal agriculture

Indirect modification of animal genomes by interspecific hybridization, cross-breeding, and selection has produced an enormous spectrum of phenotypic diversity over more than 10,000 yr of animal domestication. Using these established technologies, the farming community has successfully increased the yield and efficiency of production in most agricultural species while utilizing land resources that are often unsuitable for other agricultural purposes. Moving forward, animal well-being and agricultural sustainability are moral and economic priorities of consumers and producers alike. Therefore, these considerations will be included in any strategy designed to meet the challenges produced by global climate change and an expanding world population. Improvements in the efficiency and precision of genetic technologies will enable a timely response to meet the multifaceted food requirements of a rapidly increasing world population.

Welfare applications of genetically engineered animals for use in agriculture

The application of genetic engineering to food animals is often viewed as a means to further increase animal productivity without regard for the welfare of the resulting animals. We offer the perspective that, on the contrary, genetic engineering can, and is, being used to improve animal welfare in modern production systems. Several examples are cited from the current work in the field of animal genetic engineering that should be included in the debate over whether genetically engineered animals should be used in production agriculture. The current debate has slowed the advancement of this technology, which could play a key role in improving animal welfare and sustainability, without considering the potential benefits.

Consumption of pasteurized human lysozyme transgenic goats' milk alters serum metabolite profile in young pigs

Nutrition, bacterial composition of the gastrointestinal tract, and general health status can all influence the metabolic profile of an organism. We previously demonstrated that feeding pasteurized transgenic goats' milk expressing human lysozyme (hLZ) can positively impact intestinal morphology and modulate intestinal microbiota composition in young pigs. The objective of this study was to further examine the effect of consuming hLZ-containing milk on young pigs by profiling serum metabolites. Pigs were placed into two groups and fed a diet of solid food and either control (non-transgenic) goats' milk or milk from hLZ-transgenic goats for 6 weeks. Serum samples were collected at the end of the feeding period and global metabolite profiling was performed. For a total of 225 metabolites (160 known, 65 unknown) semi-quantitative data was obtained. Levels of 18 known and 4 unknown metabolites differed significantly between the two groups with the direction of change in 13 of the 18 known metabolites being almost entirely congruent with improved health status, particularly in terms of the gastrointestinal tract health and immune response, with the effects of the other five being neutral or unknown. These results further support our hypothesis that consumption of hLZ-containing milk is beneficial to health.

Increased gene targeting in Ku70 and Xrcc4 transiently deficient human somatic cells

The insertion of foreign DNA at a specific genomic locus directed by homologous DNA sequences, or gene targeting, is an inefficient process in mammalian somatic cells. Given the key role of non-homologous end joining (NHEJ) pathway in DNA double-strand break (DSB) repair in mammalian cells, we investigated the effects of decreasing NHEJ protein levels on gene targeting. Here we demonstrate that the transient knockdown of integral NHEJ proteins, Ku70 and Xrcc4, by RNAi in human HCT116 cells has a remarkable effect on gene targeting/random insertions ratios. A timely transfection of an HPRT-based targeting vector after RNAi treatment led to a 70% reduction in random integration events and a 33-fold increase in gene targeting at the HPRT locus. These findings bolster the role of NHEJ proteins in foreign DNA integration in vivo, and demonstrate that their transient depletion by RNAi is a viable approach to increase the frequency of gene targeting events. Understanding how foreign DNA integrates into a cell's genome is important to advance strategies for biotechnology and genetic medicine.

Lysozyme transgenic goats' milk influences gastrointestinal morphology in young pigs

Transgenesis provides a method of expressing novel proteins in milk to increase the functional benefits of milk consumption. Transgenic goats expressing human lysozyme (hLZ) at 67% of the concentration in human breast milk were produced, thereby enhancing the antimicrobial properties of goats' milk. The objective of this study was to investigate the impact of pasteurized milk containing hLZ on growth, the intestinal epithelium, and an enteropathogenic Escherichia coli (EPEC) infection in young weaned pigs. Pigs were placed into 4 groups and fed a diet of solid food and either control (nontransgenic) goats' milk or milk from hLZ-transgenic goats. Growth was assessed by weight gain. Nonchallenged pigs were necropsied after 6 wk, whereas the remaining pigs were necropsied at 7 wk following bacterial challenge. We determined the numbers of total coliforms and E. coli and examined small intestinal histology for all pigs. Complete blood counts were also determined pre- and postchallenge. Challenged pigs receiving hLZ milk had fewer total coliforms (P = 0.029) and E. coli (P = 0.030) in the ileum than controls. hLZ-fed pigs also had a greater duodenal villi width (P = 0.029) than controls. Additionally, nonchallenged hLZ-fed pigs had fewer intraepithelial lymphocytes per micron of villi height (P = 0.020) than nonchallenged controls. These results indicate that the consumption of pasteurized hLZ goats' milk has the potential to improve gastrointestinal health and is protective against an EPEC in young weaned pigs. These same benefits may occur in young children if they were to consume milk from hLZ-transgenic goats.

Birth of large calves that developed from in vitro-derived bovine embryos

High birth weights were observed in calves that developed from bovine embryos produced by in vitro maturation (IVM) and in vitro fertilization (IVF) procedures. After IVM and IVF, embryos were either co-cultured in vitro with oviductal epithelial cells or transferred into the sheep oviduct for development to the blastocyst stage. Blastocysts were transferred to the reproductive tracts of recipient heifers and cows for development to term. Birth weights and gestation periods were compared between calves that developed from in vitro-derived embryos and calves born after artificial insemination (AI) of cows in the herd from which recipient females were selected. Gestation periods were not different among the groups (P > 0.05), but calves that developed from IVM/IVF-derived embryos co-cultured in vitro were larger at birth than calves born from IVM/IVF-derived embryos that developed into blastocysts in the sheep oviduct and calves born from AI (P < 0.001). Dystocia and calf mortality were associated with large calf size at birth. These data were collected from an experiment designed for other purposes, and confounding variables and small sample size could have influenced the observed differences in birth weights. Nevertheless, the extreme birth weights of some calves suggest that abnormal prenatal growth occurs in some IVM/IVF-derived bovine embryos and that conditions for co-culture to the blastocyst stage may exacerbate the problem.

Human lysozyme expressed in the mammary gland of transgenic dairy goats can inhibit the growth of bacteria that cause mastitis and the cold-spoilage of milk

The addition of human milk components with intrinsic antimicrobial activity to livestock milk by genetic engineering has the potential to benefit milk safety and production as well as the health of the lactating animal. As a model for the dairy cow, we generated transgenic goats that expressed human lysozyme in their milk at 68% of the levels found in human milk. Milk from these transgenic animals had a bacteriostatic effect on both in vitro and in vivo growth of several microorganisms important to the dairy industry. In vitro, milk from transgenic animals was capable of slowing the growth of mastitis-causing strains of Escherichia coli (P < 0.02) and Staphylococcus aureus (P < 0.05) as well as the cold-spoilage organism Pseudomonas fragi (P < 0.02). The growth of an organism involved in cheese-making, Lactococcus lactis, was not affected by the presence of lysozyme in milk. The supplementation of control milk with purified lysozyme did not achieve the same inhibitory effect as milk from transgenic animals. In vivo, milk from transgenic animals supported less bacterial growth than control milk. This transgenic model demonstrates the possibilities offered by genetic engineering to enhance the antimicrobial nature of milk and the udder.

Consumption of milk from transgenic goats expressing human lysozyme in the mammary gland results in the modulation of intestinal microflora

Lysozyme is a key antimicrobial component of human milk that has several health-promoting functions including the development of a healthy intestinal tract. However, levels of lysozyme in the milk of dairy animals are negligible. We have generated transgenic dairy goats that express human lysozyme (HLZ) in their milk in an attempt to deliver the benefits of human milk in a continual fashion. To test the feasibility of this transgenic approach to achieve a biological impact at the level of the intestine, feeding trials were conducted in two animal models. Pasteurized milk from HLZ transgenic animals was fed to both kid goats (ruminant model) and young pigs (human model), and the numbers of total coliforms and Escherichia coli present in the small intestine were determined. Data from this proof-of-principle study demonstrate that milk from transgenic animals was capable of modulating the bacterial population of the gut in both animal models. Pigs that consumed pasteurized milk from HLZ transgenic goats had fewer numbers of coliforms and E. coli in their intestine than did those receiving milk from non-transgenic control animals. The opposite effect was seen in goats. Milk from these transgenic animals not only represent one of the first transgenic food products with the potential of benefiting human health, but are also a unique model to study the development and role of intestinal microflora on health, well-being and resistance to disease.

Transient depletion of Ku70 and Xrcc4 by RNAi as a means to manipulate the non-homologous end-joining pathway

Non-homologous end joining (NHEJ) is the major DNA double-strand break (DSB) repair pathway in mammalian cells and is likely responsible for the non-homologous integration of transgenes. In higher eukaryotes, this pathway predominates over the homologous recombination (HR) pathway and therefore may account for the low level of HR events that occur in mammalian cells. We evaluated the effects of transient RNAi-induced down-regulation of key components of the NHEJ pathway in human HCT116 cells. Treatment with siRNA targeting Ku70 and Xrcc4 reduced corresponding protein levels by 80-90% 48h after transfection, with a return to normal levels by 96h. Additionally, down-regulation of Ku70 and Xrcc4 resulted in a concomitant depletion of both Ku70 and Ku86 proteins. Biological consequences of transient RNAi-mediated depletion of Ku70 and Xrcc4 included sensitization to gamma radiation and a significant decrease in the expression of a linear GFP reporter gene. The results highlight the possibility of a successful means to manipulate the NHEJ pathway by RNAi.

Animal neuropsychology: Validation of the Intra-Dimensional Extra-Dimensional set shifting task for mice

Research in animal neuropsychology is providing an exciting new generation of behavioral tests for mice that promise to overcome many of the limitations of current high-throughput testing, and provide direct animal homologues of clinically important measures in human research. Set shifting tasks are some of the best understood and widely used human neuropsychological tasks, with clinical relevance to traumatic brain injury, schizophrenia, autism, obsessive compulsive disorder, trichotillomania, and many other disorders. Here we report the first successful modification of a human set shifting neuropsychological task, the Intra-Dimensional Extra-Dimensional (IDED) task, for use with mice. We presented mice with a series of compound discrimination and reversal tasks where one stimulus dimension consistently cued reward. Task performance improved with a new set of compound stimuli, as did reversal performance--indicating the formation of a cognitive-attentional set. We then overtrained a subset of the mice, and presented control and overtrained mice with a new compound discrimination where a novel stimulus dimension cued reward. As is the case in human control subjects, control mice persisted in responding to the now-incorrect stimulus dimension, performing poorly on this extra-dimensional shift compared with the previous intra-dimensional shift, thereby validating the task as a measure of set shifting. Furthermore, overtrained mice were impaired on this extra-dimensional shift compared with controls, further validating the task. The advantages and disadvantages of the IDED task compared to high-throughput approaches are discussed.

Quality of life after knee revision arthroplasty

BACKGROUND AND PURPOSE

Radiographic and clinical survival analyses of revision total knee replacement (TKR) are considered acceptable outcome measures. However, the full influence of revision knee replacement on the overall health status of patients remains poorly defined.

METHODS

We prospectively studied the health-related quality of life outcome in 94 patients who underwent revision knee replacement surgery over a 5-year period. Comparisons were drawn between the Nottingham health profile (NHP) scores and the Knee Society score pre-revision, and those obtained at 3 months, 1 year and 5 years after revision knee arthroplasty.

RESULTS

We found a significant improvement in Knee Society score and NHP pain scores 3 and 12 months after revision TKR (p < 0.05). No other modalities of the NHP showed a significant change. 5 years after surgery, pain was less than before revision (p = 0.2), but energy level was considered worse (p = 0.07). Knee Society scores were found to be higher pre- and postoperatively for patients undergoing revision for reasons other than sepsis than for patients with sepsis. Patients requiring implantation of a hinged prosthesis also had lower Knee Society scores than those patients receiving a non-hinged implant. Repeated revision was associated with a downward trend in Knee Society score with each surgical intervention.