PKC-θ is selectively enriched in T cells and specifically translocates to immunological synapse where it mediates critical T cell receptor signals required for T cell activation, differentiation, and survival. T cells deficient in PKC-θ are defective in their ability to differentiate into inflammatory effector cells that mediate actual immune responses whereas, their differentiation into regulatory T cells (Treg) that inhibits the inflammatory T cells is enhanced. Therefore, the manipulation of PKC-θ activity can shift the ratio between inflammatory effector T cells and inhibitory Tregs, to control T cell-mediated immune responses that are responsible for autoimmunity and allograft rejection. Indeed, PKC-θ-deficient mice are resistant to the development of several Th2 and Th17-dependent autoimmune diseases and are defective in mounting alloimmune responses required for rejection of transplanted allografts and graft-versus-host disease. Selective inhibition of PKC-θ is therefore considered as a potential treatment for prevention of autoimmune diseases and allograft rejection. T cells that are newly migrated out of thymus are naïve T cells incapable of mediating immune responses. Engagement of antigens with their T cell receptors (TCR) initiates the activation and differentiation programs that transform naïve T cells into inflammatory Th1, Th2, and Th17 effector cells or regulatory T cells (Treg), both of which participate in actual immune responses. The interference with molecules involved in T cell activation and differentiation is therefore considered an effective strategy to control the overwhelming immune responses that mediate autoimmunity and allograft rejection. However, most molecules involved in the processes of T cell activation and differentiation are not likely to be good targets for interference or inhibition because they also play essential roles in other cell types and signaling pathways. The ideal targets should meet at least the following criteria: (1) they selectively regulate T cell function; (2) small molecule inhibitors of them are easy to isolate or develop; (3) rather than inhibit, they actually promote Treg function. Ideally, inhibition of the target molecule should inhibit inflammatory T cells, and at the same time, enhance the suppressive function of Tregs. In this review, we summarize the evidence that supports PKC-θ as an excellent target for development of immunosuppressive agents.2+ and diacylglycerol (DAG); novel PKCs, including PKC-δ, θ, η, and ε, whose activation is dependent on DAG but is independent of Ca2+; and the atypical PKCs, PKC-ζ and λ, whose activation occurs independently of both Ca2+ and DAG. PKC-θ was first cloned as a novel PKC predominantly expressed in skeleton muscle , the stable cell–cell junction formed between T cells and antigen-presenting cells , 1998. T2+ mobilizer and DAG, the PKC-θ activator  Lck , which lctivator . In addictivator . Previouctivator . Howeverctivator . Upon acctivator . Severalctivator . Studiesctivator . AP-1 isctivator . Althougctivator . Li et al anergy . Several/ − mice . Althougtivation , whereastivation . Therefotivation . InhibitL that intrinsically increases resistance to apoptosis  can also activate the NF-κB pathway and it was indeed found that TLR-mediated signals can overcome the requirement for PKC-θ in T cell activation and the development of autoimmune myocarditis  that was lethal to WT mice failed to cause death due to liver injury in PKC-θ− / − mice  results from the mistaken attack on healthy liver cells by an individual’s own immune system . In mice/ − mice . Correspepatitis , and thuirrhosis . Inhibitin vitro mixed lymphocyte reaction of PKC-θ− / − T cells  model . BMT is MV virus . Moreovein vivo and selective PKC-θ inhibitors are believed to have the potential for clinical application in the treatment of autoimmunity and prevention of allograft rejection. However, PKC-θ function in T cell-mediated immune responses is dependent on the mouse models used. Therefore, the mechanisms involved in each of the diseases should be carefully examined. More questions need to be addressed prior to the clinical application of PKC-θ inhibitors including how the inhibition of PKC-θ affects the function of other tissues in vivo. It is encouraging to report that many pharmaceutical companies have developed selective PKC-θ inhibitors, and therefore many PKC-θ-regulated functions can be evaluated using these inhibitors instead of PKCθ− / − mice, which have potential developmental caveat. With the availability of PKC-θ inhibitors, it is now possible to test their efficacy in mouse models of human autoimmune diseases including EAE and arthritis, which are likely to lead to clinical trials of PKC-θ-based treatments for human diseases.PKC-θ controls fundamental functions of T cells including activation, differentiation, and survival via NF-κB, AP-1, and NFAT pathways. PKC-θ also regulates T cell-mediated immune responses The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


To investigate the clinical importance of increased integrin αvβ3 expression in the endometrium following the surgical treatment for hydrosalpinx, a total of 60 patients with hydrosalpinx and 30 patients with fallopian tube obstruction were recruited. In the implantation window, immunohistochemistry was performed to detect integrin αvβ3 expression in the endometrium of the hydrosalpinx patients before and after surgery and of patients with fallopian tube obstruction. In the implantation window, integrin αvβ3 expression levels in the endometrium of hydrosalpinx patients before surgery were significantly lower compared to those in patients with fallopian tube obstruction (P<0.05). However, there were no marked differences in integrin αvβ3 expression in the implantation window between hydrosalpinx patients after surgical intervention and patients with fallopian tube obstruction (P>0.05). Furthermore, for patients with hydrosalpinx, integrin αvβ3 expression levels in the implantation window were dramatically increased after surgery (P<0.05). Hydrosalpinx decreases integrin αvβ3 expression in the endometrium in the implantation window, and integrin αvβ3 may be an important factor influencing the endometrial receptivity of hydrosalpinx patients. Surgical treatment for hydrosalpinx can improve integrin αvβ3 expression in the endometrium during implantation. Under the influence of steroid from the ovaries, the endometrium undergoes periodical changes. Thus, the embryos can implant in the endometrium only during the proper phase . BlastocIn vitro fertilization-embryo transfer (IVF-ET) was initially applied in women with tubal factor infertility. However, numerous studies have shown that the hydrosalpinx can reduce the implantation and pregnancy rates .All patients were aged <40 years and had a regular menstrual cycle. Endocrine examinations revealed normal levels and the basal body temperature was biphasic. Hormones were not administered within 6 months before the start of the study. Cases presenting with endometriosis, uterine fibroids, polycystic ovary syndrome, ovarian cancer, infertility of unknown causes, immune infertility, chronic systemic disease, sexually transmitted disease and trophoblastic disease, and cases with a positive status for smoking and drinking were excluded from the study. Cases associated with a spouse presenting with male infertility were also excluded.Bilateral or unilateral hydrosalpinx was diagnosed by hysterosalpingography (HSG) or laparoscopy (LAP) and untrasonography. Fallopian tube obstruction was diagnosed by HSG or LAP, and ultrasonography was performed to exclude the presence of hydrosalpinx.Vaginal ultrasound-guided hydrosalpinx aspiration, laparoscopic salpingostomy, laparoscopic proximal tubal ligation or laparoscopic salpingectomy was performed.The LH peak was measured by using LH strip from Day 10 of the menstrual cycle. In addition, transvaginal ultrasonography and the test of serum sex hormones were also performed. At Days 7–8 after ovulation, the endometrium was collected at the bottom of the uterus by using a curette, and the samples were washed in normal saline to remove blood. Samples were fixed in fixation solution, embedded in paraffin and sectioned. Pathological examination was carried out to confirm that the endometrium was in the secretory phase. For patients with hydrosalpinx, the endometrium was collected during the implantation window before and after surgery; collection of endometrium was performed once in patients with fallopian tube obstruction.Mouse anti-human integrin αvβ3 monoclonal antibody (Abcam) (1:80) was used for immunohistochemistry which was performed according to the manufacturer’s instructions.Five fields were randomly selected from each section at magnification ×4,000, and the integrated optical density (IOD) was determined by using the Image-Pro Plus 5.1 Chinese software.The IOD was expressed as means ± standard deviation (SD). Statistical analysis was performed with SPSS version 13.0. A value of two-tailed P<0.05 was considered statistically significant.Under light microscopy, integrin αvβ3 was mainly expressed on the membrane and in the cytoplasm of the endometrial gland epithelial cells, while the endometrial interstitium had weak integrin αvβ3 expression. In hydrosalpinx patients, integrin αvβ3 expression levels were significantly different at the times before and after surgery (P<0.05). Before surgery, integrin αvβ3 expression in the endometrium of the hydrosalpinx patients  was markThe histologically normal endometrium dos not always have a normal function and does not always reflect normal receptivity. Currently, indicators for the evaluation of the endometrium are limited. There are numerous cytokines and molecules that are being applied to evaluate the successful implantation of embryos. In the present study, we employed integrin αvβ3 as a marker of emdometrial receptivity. To date, few studies have been conducted to investigate the effect of hydrosalpinx on integrin αvβ3 expression in the endometrium.et al , fibronectin (FN), vitroneetin (VN) and the Arg-Gly-Asp (RGD) in the human complement C3. The C terminal is intracellular and short. Different α and β subunits have distinct structures of the C terminal. Dou et al  determinet al  , perlecaet al  proposedBefore endometrial receptivity is established and after endometrial receptivity subsides, the expression of the estrogen receptor (ER) and progesterone receptor (PR) in the endometrial epithelial cells displays a decreasing tendency which depends on progesterone. Failure of progesterone regulation may significantly affect endometrial receptivity . Progestet al (et al (Our results showed that integrin αvβ3 expression in hydrosalpinx patients before surgery was markedly lower than that in patients with fallopian tube obstruction. After surgical intervention for hydrosalpinx, integrin αvβ3 expression was comparable between patients in the two groups. In addition, when compared with the level in patients before surgery, integrin αvβ3 expression was dramatically increased in the hydrosalpinx patients after surgery. These findings suggest that hydrosalpinx inhibits the integrin αvβ3 expression in the endometrium during the implantation window, which is upregulated following surgical intervention. These findings were consistent with previous studies. Lessey and Castelbaum  found thet al  also drel (et al  investigTaken together, the endometrium undergoes periodic changes which vary among individuals. Accurate evaluation of endometrial receptivity is basic for its improvement. In the present study, we investigated the effect of hydrosalpinx on expression in the endometrium. Our results demonstrate that hydrosalpinx influences integrin αvβ3 expression in the endometrium during the implantation window, reduces the receptivity of the endometrium for the implantation of the embryo and compromises the ability to maintain pregnancy. After surgical treatment for hydrosalpinx, integrin αvβ3 expression in the endometrium is increased.


Cells are constantly exposed to a large variety of lipids. Traditionally, these molecules were thought to serve as simple energy storing molecules. More recently it has been realized that they can also initiate and regulate signaling events that will decisively influence development, cellular differentiation, metabolism and related functions through the regulation of gene expression. Multicellular organisms dedicate a large family of nuclear receptors to these tasks. These proteins combine the defining features of both transcription factors and receptor molecules, and therefore have the unique ability of being able to bind lipid signaling molecules and transduce the appropriate signals derived from lipid environment to the level of gene expression. Intriguingly, the members of a subfamily of the nuclear receptors, the peroxisome proliferator-activated receptors (PPARs) are able to sense and interpret fatty acid signals derived from dietary lipids, pathogenic lipoproteins or essential fatty acid metabolites. Not surprisingly, Peroxisome proliferator-activated receptors were found to be key regulators of lipid and carbohydrate metabolism. Unexpectedly, later studies revealed that Peroxisome proliferator-activated receptors are also able to modulate inflammatory responses. Here we summarize our understanding on how these transcription factors/receptors connect lipid metabolism to inflammation and some of the novel regulatory mechanisms by which they contribute to homeostasis and certain pathological conditions. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease. ► PPARs and lipid environment form a regulatory circuit. ► Fatty acid derived molecules can regulate inflammation through PPARs. ► PPARs have anti-inflammatory roles in a number of inflammatory diseases. ► A number of outstanding questions about the biology of PPARs are still unanswered. Treatment of rodents with these compounds also increased the rate of β-oxidation of fatty acids and caused hepatomegaly and carcinogenesis, which did not occur in humans 2Inflammation is a multistep process by which the host responds to the perturbation of homeostasis. Microbial infections, injuries or altered physiological conditions all have the potential to trigger an inflammatory reaction. Upon elimination of the source of inflammation, a resolution phase ensues in which the damaged surrounding tissue is repaired and homeostasis is restored. Inflammatory reactions can be divided into acute inflammation, which is resolved in a relatively short time, hours or days, and chronic inflammation, which occurs over a longer period of time. Typically, chronic inflammatory reactions develop gradually from an acute reaction if the host is not able to eliminate the inflammatory inducer . For instance, saturated fatty acids and different classes of polyunsaturated fatty acids (PUFAs) were demonstrated to modulate inflammation An inflammatory reaction can be regulated in a number of different ways. The detection and interpretation of inflammatory signals, the response of the activated immune cells (such as cytokine release), the reaction of the surrounding tissue to inflammatory agents and to immune mediators as well as the resolution/repair phase are all targets of regulatory mechanisms. Interestingly, several regulatory mechanisms of the inflammatory reaction were demonstrated to be influenced by lipid molecules. Due to the fact that PPARs are specialized receptors to detect fatty acid derived signal molecules, they are key candidate for being the receptors that transduce a fraction of the lipid mediated inflammatory signaling events. Indeed, several instances were identified in which certain fatty acid derived molecules were shown to activate PPARs and modulate inflammation The role of PPARs in inflammation is especially relevant in the case of metabolic syndrome and atherosclerosis. These are diseases of lipid (and glucose) metabolism with an underlying inflammatory component. Metabolic syndrome is a cluster of symptoms  that are often associated and significantly increase cardiovascular risk. Currently two main competing theories are proposed that could explain the emergence of impaired glucose tolerance in these patients. The lipotoxicity theory Due to their role in the above medical conditions, the metabolic roles of PPARs have been the target of intensive research. As their functions in inflammation slowly emerged, an increasing number of studies were devoted to dissect the role of PPARs in different types of inflammation, as well .3As already noted, PPARs belong to the nuclear receptor hormone superfamily. These proteins are transcription factors that are not only able to bind to DNA and regulate gene expression but they also serve as intracellular receptors by binding lipid molecules. This superfamily emerged in the early metazoan evolution and underwent an intensive evolutionary divergence 4Xenopus and other vertebrate genomes Xenopus. Mammalian PPARβ/δ, however, showed considerable divergence at the sequence level from the Xenopus PPARβ. Because of the lesser degree of sequence homology, this subtype in the mammals was alternatively named as PPARβ, PPARδ, FAAR, NUC1 or PPARβ/δ.As noted earlier, there are three subtypes of PPARs in vertebrates, PPARα (NR1C1), PPARβ/δ (NR1C2) and PPARγ (NR1C3). Mouse PPARα was cloned first, which was followed by the cloning of all three subtypes from 4.1in vitro transactivation assays. In these cellular assays nuclear receptors are expressed ectopically in cells and the candidate ligands are used to activate the receptors. A marker of the transactivation activity of the nuclear receptor is then measured. This marker could be e.g. a known target gene for the corresponding receptor, or a signal that derives from an expression construct where a PPAR target sequence linked to a core promoter and a reporter (e.g. luciferase) gene. The second class of methods comprises biophysical techniques that measure the physical binding of candidate ligands to the receptors , the Ligand Induced Complex (LIC) assay or the Coactivator Dependent Receptor Ligand Assay (CARLA)). The detailed description of these methods is outside the scope of this review. However, it is important to note that both classes of techniques carry their own weaknesses. When a candidate ligand causes enhanced gene expression in transactivation assays it is difficult to determine whether the candidate ligand itself binds to the receptor. Alternative explanations for the enhanced transactivation activity can be that the candidate ligand is actually a precursor of a true ligand, or that it initiates signaling events that will culminate in generating an unidentified ligand. The weakness of the biophysical methods is that although they provide a direct proof for the binding of a candidate ligand to the receptor, they do not guarantee that these molecules are present in the cells at high enough concentrations to serve as effective endogenous ligands. Indeed, most of the putative ligands are required to be present in vivo at such a high concentrations to efficiently activate PPARs that their function as bona fide PPAR ligands is often questioned. This leads to the paradox situation that although numerous ligands are suspected to be PPAR activators, the real identity of true endogenous ligands of PPARs is still very much debated. Here we provide a short summary of the major groups of the candidate PPARs ligands. More detail regarding the ligands of different PPAR subtypes will be provided in the corresponding sections.PPARs were originally described as orphan nuclear receptors, but soon a plethora of potential endogenous ligands were described. There are two major class of assays used to identify ligands. One class is represented by e.g. estrogen receptor or glucocorticoid receptor) that bind a very limited number of highly specific ligands at high affinity. This promiscuous ligand binding of PPARs is also reflected in the size of the ligand binding pocket of the PPAR proteins. The ligand binding pocket of PPARs is characteristically larger than that of classic nuclear receptors. It is possible that the unusually large ligand binding pocket enables PPARs to bind such a variety of different ligands.Due to the fact that three subtypes do not show strict ligand specificity, it is logical to discuss the ligands of all PPAR subtypes together . If a cee.g. α-linolenic acid with C18:3, or docosahexaenoic acid with C22:6), and certain ω6-polyunsaturated fatty acids (such as linoleic acid with C18:2 and arachidonic acid with C20:4). Certain saturated fatty acids (such as myristic acid with C14:0 and stearic acid with C18:0) were also found to bind to PPARα. The finding that dietary fatty acids can bind to and activate nuclear receptors and regulate gene expression akin to small molecule endocrine hormones caused a paradigm shift in how we think about the role of dietary fatty acids. Another group of PPAR ligands comprises the conversion products of essential fatty acids (mainly arachidonic acid) by lipoxygenases or cyclooxygenases. The best examples for eicosanoids that are possibly PPARα ligands are hydroxyeicosatetraenoic acids (e.g. 8(S)-HETE) and leukotriene B4 (LTB4), while prostacyclin (PGI2) Molecules that were found to bind physically to PPARs include polyunsaturated fatty acids (PUFAs) such as certain ω3-polyunsaturated fatty acids (bona fide endogenous ligands? To answer this question it would be necessary to know which candidate molecules are present intracellularly at a concentration that is in good agreement with their dissociation constant (Kd) values. Not only is this a technically extremely challenging task, but it is not fully understood how these lypophilic molecules are transported across the cell membrane, stored or metabolized in the cells. It is possible that certain candidate ligands that are present at low extracellular concentrations (which would seemingly preclude them from being endogenous ligands) can reach high concentrations locally. Among the candidate ligands listed above, the polyunsaturated fatty acids that can bind to PPARs are potentially true endogenous ligands for PPARα. It is less certain if any of the saturated fatty acids can work as ligands for PPARs. The eicosanoids (such as 8(S)-HETE for PPARα, 15d-PGJ2 for PPARγ and 15-HETE for PPARβ/δ) are often cited as lipid metabolites that have the potential to reach high enough concentrations to activate PPARs bona fide ligand(s) for PPARs is highly controversial.Which of the above mentioned candidate ligands are PPARs also have synthetic ligands that can easily be used to interrogate the transcriptional activities of the PPARs in cells that express different subtypes of PPARs. All three subtypes have highly (but not exclusively) specific agonists 4.2PPARs form heterodimers with their obligate partners, the members of another subfamily of nuclear receptors, RXRs . According to the simplified model, upon ligand binding PPAR/RXR heterodimers recognize and bind to specific DNA sequences, called PPAR response elements (PPRE) All three PPAR subtypes are believed to bind to canonical DR1 elements. Due to the fact that certain cell types express more than one PPAR subtype, the question arises what determines PPAR binding to a certain DR1 element in these cells e.g. 9-cis retinoic acid or various fatty acids). It is possible that in cells in which there is no PPAR ligand available but RXR ligands are present, functional PPAR-RXR heterodimers can still bind to DR1 elements and regulate gene expression. When and to what extent this might happen is a complex question, and could be influenced by the target gene, the cell type and possibly by uncharacterized fine features of DR1 elements A further twist in the recognition of DR1 elements by PPAR-RXR heterodimers is the fact that the heterodimeric partner, RXR, is also a nuclear receptor and has its own cognate ligand  specific for the most part, it is also well documented that there are agonist effects that are mediated by the other PPARs or not mediated by PPARs at all, especially when these agonist are applied at very high concentrations.−/− animals are not viable and die in utero due to the deleterious effects of PPARγ deficiency in placentation. As a corollary, deficiency in PPARγ (and partly in PPARβ/δ) can be studied in heterozygous animals or in mice in which the PPARγ gene is disrupted by a Cre/lox mediated deletion only in certain cell types e.g. macrophages, T cells or adipocytes, are viable and breed easily, but often show increased susceptibility to different experimentally induced diseases. A recently applied strategy used to circumvent the deleterious effects of placental PPARγ deficiency makes it possible to generate full body PPARγ knockout animals in which PPARγ functions are preserved in placental trophoblasts but lost in virtually all embryonic tissues. In these mouse models the Cre recombinase was under the control of the Mox or the Sox2 promoter PPAR functions can also be studied in animal models of disease. There are genetically modified mouse strains available for each PPAR. Whole body knockout of PPARα causes relatively minor phenotypes in unchallenged animals Finally, clinical studies, medical practice and human genetics are also important sources of information that can help dissect the functions of PPARs. Millions of people worldwide have been treated with synthetic agonists of PPARγ for impaired glucose tolerance, or with PPARα agonists to normalize serum lipid levels. Statistical analysis of the incidence of diseases where PPARs are implicated can corroborate or refute results derived from cellular or animal studies.4.4in vivo studies suggest that PPARs can exert their anti-inflammatory effects by several distinct molecular mechanisms  that have direct inflammatory roles. Alternatively, it is also possible that PPARs modulate inflammatory processes indirectly by altering lipid metabolism. According to this scenario, PPARs would directly modify the intra-, and extracellular pool of lipid molecules available in the body, and this altered lipid environment would initiate secondary regulatory processes. Such a mechanism is described in human dendritic cells (DCs) 5There are two distinct isoforms of PPARγ, termed PPARγ1 and PPARγ2, which are transcribed from the same gene. PPARγ2 differs by an extra N terminal motif (28 amino acids in human or 30 in mouse) 5.1The canonical PPAR activity is the ligand dependent transactivation, in which liganded PPARγ forms heterodimers with RXR, and the PPARγ/RXR heterodimers recruit a large protein complex of co-activators required for the regulation of transcription. With the help of these co-activators, PPARγ/RXR heterodimers bound to PPREs in the enhancers of target genes will modulate the activity of the basal transcription machinery. This classic transactivation mechanism is well characterized at the molecular level. It is believed that such ligand mediated PPARγ transactivation usually results in the upregulation and not repression of the target genes.There are alternative mechanisms by which PPARγ can regulate gene expression. These alternative mechanisms are especially important for the understanding of the regulation of immune response by PPARγ. The reason behind this is that it is very difficult to interpret the role of PPARγ in the immune system solely based on the classic transactivation model. No canonical inflammatory regulators have been described so far that are robustly upregulated by agonist activated PPARγ. Moreover, at least a subset of the anti-inflammatory effects of PPARγ is due to ligand dependent gene repression, which is difficult to reconcile with the classic model of the agonist action of positive regulation of gene expression.trans-repression if PPARγ action is not mediated by its binding to canonical PPRE target DNA sequences. Maybe the best characterized model is the case of ligand dependent transrepression of inflammatory genes. According to this model e.g. NOS2 (inducible nitric oxide synthase 2)) that keeps these genes repressed in the absence of inflammatory signals. For an efficient expression of NOS2 upon LPS (lipopolysaccharide) induced TLR4 (toll-like receptor 4) activation, two requirements must be met. First, the inhibitory complex must be removed from the promoter, and only then can the key immune regulator NF-κB (nuclear factor kappa-light chain-enhancer of activated B cells) activate NOS2 expression. The removal of the inhibitory complex is normally carried out by the ubiquitin proteasome system. In cells that receive concomitant PPARγ ligand and LPS treatments, a fraction of the liganded PPARγ will be SUMOylated on lysine K365. The SUMOylated PPARγ will not be able to bind its regular heterodimerization partner, RXR. Instead, it will bind to the repressor complex located on the promoter of inflammatory genes. The binding of PPARγ to these repressor complexes will block the ubiquitination and hence the efficient removal of the repressors. As a result, ligand bound PPARγ will maintain the repression on the promoter of inflammatory genes, such as iNOS2, even in the presence of active TLR4 signaling. Other forms of transrepression also exist. PPARγ was shown to bind directly other transcription factors, such as NF-κB or activator protein 1 (AP-1) trans-repression of other transcription factors, play important roles in ligand-induced repression. Furthermore, the in vivo relevance and the contribution of these proposed mechanisms to the inhibition of gene expression remains to be further established.There are a number of distinct mechanisms responsible for ligand-dependent gene repression by PPARγ, all occur through the indirect regulatory effects of ligand binding. The resulting negative regulation of gene repression is termed 5.2via the action of MAP kinases, as witnessed by the enhanced expression of the robust PPARγ target gene, aP2  The consequence of ligand mediated activation of PPARγ can be modulated by phosphorylation. The first study described the phosphorylation of PPARγ2 at serine-112 by MAP kinases. This phosphorylation, which reduced the transcriptional activity of PPARγ e.g. in the regulation of inflammation. This is possible because cdk5 was reported to modify the antiproliferative effect of PPARγ Recently a novel mechanism for the posttranslational modification of PPARγ was described 5.3via transrepression of other transcription factors Myeloid cells were the first immune cells in which the expression and the function of PPARγ were studied. Murine bone marrow derived and peritoneal macrophages, as well as human monocytic cells (U937) were included in these analyses. Bone marrow macrophages expressed PPARγ at very low levels, but thioglycolate elicited peritoneal macrophages showed a marked upregulation of PPARγ. Additionally, IFN-γ (interferon-gamma) activated macrophages that also received PPARγ ligand treatment phenotypically resembled resting macrophages. The idea was tested if PPARγ is a negative regulator of macrophage differentiation and activation. It was found that treatment of IFN-γ activated macrophages with the synthetic ligand rosiglitazone or with the endogenous ligand 15d-PGJ2 blunted the expression of inflammatory genes, such as the inducible nitric oxide synthase, gelatinase B and scavenger receptor A genes. Interestingly, a number of target sites for immunologically relevant transcription factors ) were detected in the proximal and distal promoters of the regulated genes. This suggested that liganded PPARγ acted In two other early studies human monocytes, the human myelomonocytic cell lines THP1 and HL60 and murine lymph node macrophages −/− macrophages via PPARγ independent mechanisms. Another caveat in interpreting these and other data is the fact that the observed gene expression changes are not in line with the classical model of positive regulation of target genes by ligand activated PPARγ. Clearly, other models of PPARγ actions, such as ligand dependent or independent trans-activation could be responsible for at least a subset of gene expression changes mediated by PPARγ. When the gene expression changes in rosiglitazone treated or untreated murine peritoneal macrophages per se, but is more likely a downstream effector of the IL-4 signaling pathway in vivo function is probably linked to IL-4/IL-13 driven processes. These cells have a documented role in immunity against parasites The above papers laid the foundation for the field that has seen an ever increasing number of publications on PPARγ functions in myeloid cells since then. Paradoxically, these studies also shed light on the controversies of the field. One such controversy is that 15d-PGJ2, the candidate endogenous ligand used in these and other studies is not a very specific PPARγ ligand. Additionally, the ligand concentration used to inhibit inflammatory responses were higher than it would be expected based on the Kd value for the ligands. For these reasons the involvement of the other PPAR subtypes  in mediating the effects of PPARγ ligands could not be excluded. These points are very well illustrated by the findings that showed that 15d-PGJ2 and TZD drugs were similarly effective in inhibiting LPS induced inflammatory cytokine release in wild type as well as in PPARγAfter the characterization of PPARγ in macrophages, a closely related cell type, dendritic cells (DC) came to the spotlight of PPARγ research. Dendritic cells are professional antigen presenting cells that regulate both the innate and adaptive arms of the immune response. Murine immature and mature splenic DCs were shown to express PPARγ via a third mechanism. IL-4 signaling in these cells is transduced predominantly by the JAK/STAT6 pathway. It was found that upon simultaneous PPARγ and IL-4 activation of macrophages STAT6 was able to bind PPARγ and modified its DNA binding and transcriptional activity e.g. during PMA activation of the monocytic THP1 cell line, during the in vitro differentiation of human peripheral monocytes into DCs, or during the early stages of murine bone marrow derived macrophage differentiation (unpublished observation). The above features of PPARγ activity in myeloid cells raise the interesting question of which are the physiologically relevant PPARγ responsive cells in vivo. It is possible that the typical model cell types that are used to study macrophage/DC PPARγ activity; bone marrow derived macrophages, peritoneal macrophages and monocyte derived macrophages/DCs  do not represent well the true PPARγ responsive cell populations.There are several questions that are raised by the results from studying PPARγ in myeloid cells, including macrophages and DCs. One interesting observation is that the level of PPARγ expression and the activity of PPARγ, even when synthetic ligands are present, do not show strong correlation. Murine peritoneal macrophages express relatively high level of PPARγ, yet they were shown to be rather unresponsive to ligand treatment. There must be other mechanisms, such as the availability of other regulators, co-factors or signaling molecules, that can regulate the responsiveness of PPARγ. This phenomenon might be linked to the fact that a robust PPARγ response can be seen in these cells if they also receive simultaneous IL-4 treatment, which was thought to be mediated by an enhanced PPARγ expression in the presence of IL-4 Other immune cells such as T cells were shown to express PPARγ1 +/− animals which showed no difference in the T cell compartment when compared to wild type mice exhibited enhanced B cell proliferative responses to stimulation. Contrary to earlier findings, B cells of PPARγ+/− animals exhibited increased viability.PPARγ expression was also detected in B cells PPARγ expression was also described in isolated primary natural killer (NK) cells and in NK cell lines 5.4via the modulation of gene expression. It is, however, difficult to predict the in vivo consequences of PPARγ activation solely based on the results obtained from in vitro studies. First, immune responses can be regulated by many non-cell autonomous mechanisms, and activation of PPARγ in isolated population of target cells fails to detect these regulatory circuits. Second, it is possible that the cell types that can be isolated and cultured in a reasonable quantity do not represent the cell types in which in vivo activation of PPARγ has important functions. For these reasons, animal models of disease have been used to elucidate the physiological or pathological roles of PPARγ.Studying PPARγ activation in isolated primary cells or in cell lines can reveal important regulatory mechanisms by which lipids can influence inflammatory responses of the investigated cell type Inflammatory bowel diseases (IBD) (Crohn's disease and ulcerative colitis) are inflammatory conditions in which the role of PPARγ was investigated. There are several murine models for the generation of an intestinal inflammation reminiscent in some aspects to different forms of human IBD. IL-10 knockout mice develop intestinal inflammation spontaneously, while intrarectal administration of dextran sodium sulfate (DSS) or 2,4,6-trinitrobenzene sulfonic acid (TNBS) in wild type mice reliably induces ulcerative colitis. The involvement of PPARγ in inflammatory bowel diseases was investigated in several mouse models and the general picture emerged that PPARγ activity protected from IBD. Due to the fact that PPARγ is normally expressed in both colonic epithelial cells and in resident macrophages of the colonic mucosa, PPARγ activity in both cell types had the potential capacity to ameliorate disease progression. The chemically induced inflammation model was used in mice heterozygous for PPARγ via the reduction of Th17 T cell differentiation Experimental autoimmune encephalomyelitis is an animal model of brain inflammation, in which the role of PPARγ in the regulation of inflammation can be studied. EAE in rodents is accompanied by demyelination. This characteristic of EAE makes it be a useful model for human multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM). The first experiments demonstrated that the endogenous ligand 15d-PGJ2 and the TZD drugs troglitazone and ciglitazone were able to ameliorate experimentally induced EAE Experimental autoimmune myocarditis is another model in which the potential involvement of PPARγ was investigated. When autoimmune myocarditis was induced in Lewis rats by immunization with cardiac myosin, administration of synthetic PPARγ ligands ameliorated disease severity. It was suggested that the inhibition of the expansion of autoreactive T cells and a shift in the Th1/Th2 balance were responsible for the beneficial effects of the agonist treatment −/− cells worsened the outcome of atherosclerosis, strongly suggesting a role for PPARγ in macrophages involved in lesion formation Two medical conditions that develop due to dysregulation of lipid metabolism, atherosclerosis and metabolic syndrome have an underlying chronic inflammatory component. Due to the fact that PPARγ regulates lipid metabolism and also has anti-inflammatory activities, it is a reasonable target in studies that dissect lipid metabolism derived and inflammatory components of these diseases. Li et al. found that rosiglitazone treatment of high fat diet fed animals lead to a reduction of the lesion areas in high fat diet fed LDL-receptor knockout mice. Surprisingly, the beneficial effect of PPARγ activation was detectable only in male mice −/−, PPARβ/δ−/− or LXRα−/−  hematopoietic cells. It was also found that the main site of the insulin sensitizing activity of ligand activated PPARγ was, in fact, adipose tissue Unexpectedly, macrophage PPARγ was shown to be a regulator of insulin sensitivity in two metabolic studies 5.5Human PPARγ mutations and single nucleotide polymorphisms (SNPs) were associated with metabolic and inflammatory diseases. Barroso et al. examined all the coding exons of PPARγ 1 and 2 in 85 unrelated patients with severe insulin resistance Several single nucleotide polymorphisms (SNPs) of PPARγ were identified. The most commonly studied SNP, Pro12Ala, has firmly been demonstrated to influence metabolic status of patients 6PPARα expression was predominantly found in the liver, but was also found to be expressed in cardiac myocytes, proximal tubular epithelial cells of kidney, skeletal muscle, large intestine epithelium, endothelial and smooth muscle cells as well as immune cells including macrophages, lymphocytes and granulocytes 6.1bona fide ligands. As already mentioned, dietary fatty acids can bind to and activate PPARα. Consequently, there is an intriguing possibility that our diet directly influences our immune system by activating transcription factors and therefore regulating gene expression. The classical model described in the PPARγ section for agonist activated PPAR transactivation is also applicable to PPARα. Similarly to PPARγ, there is hardly any immunologically relevant gene whose positive regulation by PPARα can be explained by the classical, agonist mediated transactivation model. The only notable exception may be the case of IL-4 regulation in lymphocytes It is important to note that PPARα is the only subtype of PPARs whose candidate endogenous ligands are indeed most likely Similarly to PPARγ, PPARα can also regulate gene expression by a variety of transrepression mechanisms. Ligand dependent transrepression was demonstrated in aortic smooth muscle cells in vivo, and if PPARα agonists could be used in combination therapies with glucocorticoids to alleviate inflammatory conditions.Interestingly, a new twist in the mode of transrepression was described by Bougarne et al. 6.2Several posttranslational modifications were described for PPARα. Insulin mediates the phosphorylation of Ser12 and Ser21, which enhance the transactivation capacity of PPARα 6.3The expression of PPARα has been reported in several immunologically relevant cell types. In human monocyte derived macrophages it was found that ligand activation of PPARα induced apoptosis 6.4−/− mice showed prolonged inflammation when arachidonic acid or its metabolite LTB4 were used to trigger inflammation, but the same effect did not occur when a distinct inflammatory agent, phorbol esther was used. Due to the fact that the LTB4 is not only an inflammatory molecule but also an efficient ligand for PPARα, the results suggested the existence of a negative feedback mechanism limiting the duration inflammation.The first report that suggested that PPARα could control inflammation Interestingly, PPARα showed a dual role in the LPS induced endotoxic shock model in vitro.Other animal experimental models also suggested that PPARα has an anti-inflammatory role. In a murine model of human asthma Delayre-Orthez et al. examined the role of PPARα in another airway inflammation model −/− animals exhibited enhanced production of TNFα, IL-1β in the pleural exudate. Interestingly, D'Agostino et al. demonstrated that the acute intracerebroventricular administration of an endogenous PPARα ligand, palmitoylethanolamide, had potent anti-inflammatory effects in the carrageenan-induced paw edema model when palmitoylethanolamide was administered prior to the carrageenan injection In the carrageenan-induced paw edema and carrageenan-induced pleurisy models of inflammation, Cuzzocrea et al. found that deletion of PPARα led to an increased paw edema and pleural exudate formation and neutrophil infiltration Several experiments suggest a potential role of PPARα in colonic inflammation and maintenance of mucosal tissue homeostasis. In the IL-10 knockout mice model, Lee et al. demonstrated that the PPARα ligand fenofibrate could decrease colonic INF-γ and IL-17 expression and leukocyte infiltration Other studies investigated the role of PPARα in mouse model of atopic dermatitis. Atopic dermatitis can develop in mice following topical sensitization and challenge with ovalbumin or oxazolone. Staumont-Sallé et al. described that PPARα deficient mice showed enhanced dermal recruitment of inflammatory cells, IgG2a and IgE production, epidermal thickening as well as lung inflammation and airway hyperresponsiveness following sensitization with ovalbumin The role of PPARα in experimental autoimmune encephalomyelitis was also investigated.−/− animals. PPARα expression in CD4+ T cells was found to be higher in male than in female mice, suggesting sex specific role of PPARα in T cells mediated autoimmunity Lovett-Racke et al. demonstrated that PPARα agonists could be used to ameliorate disease progression The liver is the centre of the lipid and carbohydrate metabolism as well an important regulator of inflammation. Acute phase proteins are among the key molecules by which liver is able to modulate inflammation are. PPARα was demonstrated to influence systemic inflammatory responses by regulation of the acute phase response. The PPARα ligand fenofibrate inhibited the expression of IL-6 induced acute phase response proteins including fibrinogen-a, -b and -g, serum amyloid A and haptoglobin in the liver of wild type but not in PPARα knockout mice. As an additional proof for the role of PPARα in acute phase response, fenofibrate treated hyperlipidemic patients were shown to have decreased plasma concentration of fibrinogen, C-reactive protein, serum amyloid A, plasminogen and a2 macroglobulin +/+ ApoE−/− littermates −/− mice following bone marrow transplantation from PPARα−/− mice showed increased size of atherosclerotic lesions in aorta compared to LDLR−/− mice with wild type derived bone marrow, suggesting complex role of PPARα in development of atherosclerosis PPARα has the potential to affect atherosclerosis at two levels. First, PPARα is a regulator of lipid metabolism, and the loss of PPARα function causes higher than normal levels of atherogenic lipoproteins. Alternatively, PPARα could impact the inflammatory component of atherosclerosis. Tordjman et al. demonstrated that PPARα/ApoE double knockout mice showed higher serum level of atherogenic lipoproteins, but decreased aortic atherosclerotic lesions, lowered insulin resistance and blood pressure as compared to PPARα−/−, but not in wild-type animals Similarly to PPARγ, it is possible that PPARα activity also modulates obesity associated inflammation either through its metabolic activity or anti-inflammatory effects. Induction of obesity with high-fat diet in PPARα knockout or wild type mice suggested that PPARα protected against obesity-induced chronic inflammation in the liver. Plasma markers of liver injury and inflammation, including serum amyloid A and alanine aminotransferase activity, were increased in high-fat diet fed PPARα7Among the PPARs, PPARβ/δ has been the least studied subtype so far. However, important advances were made in recent years in understanding the metabolic and inflammatory functions of PPARβ/δ. PPARβ/δ is expressed almost ubiquitously 7.1The involvement of PPARβ/δ in the regulation of lipid metabolism has been well established based on knockout and overexpression studies in transgenic mice 7.2e.g. monocyte chemoattractant protein 5 (MCP-5/CCL12), IL-1β, TNFα, IL-6 and VCAM-1 (vascular cell adhesion molecule 1) Several inflammatory cell types express PPARβ/δ. PPARβ/δ activity in macrophages was thoroughly studied due to the connection of PPARβ/δ to atherosclerosis. Several inflammatory genes are regulated by PPARβ/δ in murine macrophages, 7.3−/− animals showed impaired infiltration of immune cells to the site of the injury, which resulted in delayed healing. On the other hand, PPARβ/δ+/− heterozygous animals exhibited a hyperproliferative keratinocyte reaction.Skin inflammation and wound healing was the first inflammatory model in which the role of PPARβ/δ was investigated. Michalik et al. found that all PPARs were expressed in the skin during fetal development of mice The involvement of PPARβ/δ in atherosclerosis was also investigated Leishmania major was impaired in cells that received PPARβ/δ ligand treatment. These results suggested again that PPARγ and PPARβ/δ, but not PPARα, are regulators of the M2 macrophage development.Interestingly, PPARβ/δ also influenced the development of alternatively activated macrophages (M2 macrophage). Arg1, an M2 marker gene that is under PPARγ regulation in murine myeloid cells −/− animals displayed more inflammatory foci in the central nervous system. This was partly due to an expanded population of CD4+ cells that produced both IFN-γ and IL-17. PPARβ/δ ligand treatment of wild type CD4+ cells in serum-free medium resulted in a decreased production of IFN-γ by wild type but not PPARβ/δ−/− cells.Another animal model in which PPARβ/δ shows overlapping functions with other PPARs is EAE −/− animals, these mice developed a lupus erythematosus-like autoimmune disease.Recently, another aspect of the anti-inflammatory role of PPARβ/δ was revealed 8via these proteins. However, in spite of the wealth of the sometimes conflicting pieces of information available, key issues are still unresolved. These include the true nature of ligand(s) and the way it/they are generated, the predominant mechanisms of action, the genomic loci regulated along with target genes and the tissue and disease specific contribution of the individual receptors to cellular function and diseases. Further progress will be fuelled by emerging novel approaches and methodologies such as in vivo ligand detection and determination and single cell biophysical and microscopic technologies to detect ligand–receptor and ligand–co-factor interactions in vivo. Systematic efforts to determine genomic binding sites, the identity of co-binding transcription regulators and associated histone marks to reveal the predominant mechanisms of action including the often overlooked transcriptional repression are also needed. Finally the field needs to go down the painstaking path of evaluating the role of each of the three receptors in individual cell types using advanced mouse genetics approaches combined with disease models to truly define the regulated gene sets and pathways. These along with clinical advances can provide us with the insights into the intricate relationship between lipids, receptors and inflammation. Identification of mechanisms of endogenous ligand generation and the direct target genes of each of the receptors in every relevant tissue would be particularly useful in order to identify new therapeutic targets for the biotech and pharma industries. Such new developments would provide further and a much needed boost for the field.PPARs are a truly fascinating set of molecules. They represent a direct link between changes in the intracellular lipid milieu and the expression of the genome. It is intriguing to see how literature on the activity of these transcription factors is broadening, largely due to the availability of synthetic ligands, animal models and drugs acting


Lama glama) and alpaca (Vicugna pacos) are the only large domesticated animals indigenous to the Americas. Pastoralism occupies a fundamental economic, social and religious role in Andean life. Today, camelid livestock are confined to the ecozone of the puna , while their presence on the Pacific coast during pre-Hispanic times is attested by archaeological skeletal remains. This study aims to document herding practices on the northern Peruvian coast during the Early Intermediate Period (200 BC-600 AD) by gaining insights into diet, location of breeding and mobility of archaeological camelids from the funerary and ritual contexts of two Mochica sites, Uhle Platform in Huacas de Moche and El Brujo. The three first early years and the long-term life histories of the animals were documented by the combined bulk analysis of bone collagen (δ13Ccol and δ15Ncol) and bone structural carbonate (δ13Cbone and δ18Obone) and the serial analysis of structural carbonate of molar tooth enamel (δ13Cenamel and δ18Oenamel). Mochica camelids were bred in the low and/or middle valleys, unlike their modern counterparts, who are restricted to highland puna C3 pastures. Archaeological camelids had diverse and complex life histories, usually with substantial maize foddering. An ontogenetic switch in diet and possible residential mobility during the course of life were identified for some specimens. Although the inference of geographic origin from δ18Obone and δ18Oenamel values was limited because of the lack of understanding of the influence of environmental and biological factors, tooth enamel analysis has great potential for exploring camelid herding practices and Andean pastoralism. Our study suggested that Mochica herders adapted their practices to the difficult lowland environment and that herding practices were varied and not restricted to breeding at higher altitudes. The role of maize in different aspects of the economic life of the Mochicas is also underlined.Llama ( Vicugna pacos) and llamas (Lama glama) were domesticated 4,000–6,000 years ago, and experienced an intensification in livestock management from at least the end of the Early Horizon (900–400 BC) Andean pastoralism and the establishment of trade routes between different ecological zones, the so-called concept of Andean verticality, is one of the foundations for the emergence of complex societies in the pre-Hispanic world puna that comprises plateaus above 3,500 masl, and more precisely between 3,900 and 4,500 masl Puna conditons are characterized by hypoxia, low intra-annual variation in temperature but daily variation as high as 20°C and a higher precipitation rate than that of the lower western slopes of the Andes  which are naturally conducive to llama and alpaca breeding. The optimum life conditions for llamas and alpacas vary according to the function the animal serves bofedales pasturelands at higher altitudes than llama herds. The presence of domestic camelids in remote and dramatically different habitats, like the Pacific coast – characterized by a higher mean temperature and higher seasonal variations in temperature than the puna and almost no precipitation – is attested by skeletal remains, textiles and iconography from at least 200 BC onwards bofedales of the puna. Only a few habitats located in the lower part of the valleys, fog oases (lomas) developing in the foothills, or irrigated fields could have provided pastures rich enough to sustain large herds. Maize foddering, diet supplements comprising marine resources  or seasonal transhumance to mid-altitude valleys could have been used to compensate low food availability. Therefore, the breeding of flocks in an environment radically different from their original environment during pre-Hispanic times raises questions about the nature and the location of the dietary resources necessary to maintain animals and the seasonal or year-round nature of their keep. Furthermore, the presence of camelid remains on the north coast is not in itself indicative of local herding. With the exception of juveniles (under two years old) that have not been documented to travel long distances puna and subsequently brought to the coast. In order to answer these questions and document the management systems developed by coastal breeders it is essential to reconstruct camelid diet and zone of growth.Today, camelid husbandry is essentially restricted to the highlands 13C), nitrogen (δ15N), oxygen (δ18O) and strontium (87Sr/86Sr) in human and animal remains found in archaeological contexts are a primary source of information on the life history of humans and animals. The scope of isotopic analyses is still limited in South America compared to other regions but it is growing rapidly. The western slopes of the Andes present a wide variety of ecological zones 18O water data remains to be established on a local scale 13C and δ15N values that enable, for instance, the identification of maize consumption 13C and δ15N values, as well as δ18O and 87Sr/86Sr values (that rely on climate and geology) can also be used to assess animal mobility between geographical areas that present distinct isotopic values Measurements of stable isotopes of carbon  was used to retrospectively record the animals’ early life histories. Enamel δ13C and δ18O values were compared to those of bone apatite (δ13Cbone and δ18Obone) and to δ13C and δ15N values for bone collagen (δ13Ccol and δ15Ncol), to document diachronic changes in diet and growth location.The serial analysis of tooth enamel has been used successfully in different regions of the world to document herding practices The Mochica territory ranged from the Piura Valley to the Huarmey Valley on the northern coast of Peru . Mochicagarúa, which occur between May and December, and the resurgence of the underground water network Lomas develop on the foothills between 200 and 1,000 masl and present specific vegetation which is particularly attractive to wildlife and game. The northern boundary of the lomas is located on the foothills of the Cerro Campana, a few kilometers from the modern city of Trujillo. The rivers and the valleys are the most active and dynamic components of the coastal environment and have been classified as oases by Dollfus lomas, river mouths and valleys, the arid desert environment of the coast is not conducive to agriculture and permanent domestic animal herding. The sustainability of diversified agriculture was made possible by the development of a complex irrigation system formed of canals, which undoubtedly constituted one of the bases for the expansion of the Mochicas into each valley At the latitude of the Moche region, the coast is a zone approximately 25 km wide, bordered to the west by a cool and rich ocean and to the east by the foothills of the Andes . The coaThe site of Huacas de Moche is located on the left bank of the Moche Valley, 4 km from Trujillo . It compThe site of El Brujo is located 60 km north of Trujillo, close to the village of Magdalena de Cao, in the lower part of the Chicama Valley , along tAll necessary permits were obtained for the described study, which complied with all relevant regulations. Permissions were obtained from the Ministerio de Cultura of Peru to study archaeological remains.Lama sp.) camelids and small camelids (Vicugna sp.). Only Lama sp. were identified in our two archaeological sites and were probably llamas. However, this does not preclude the presence of alpacas on the coast during pre-Hispanic times. Eight archeological camelid specimens curated at the site Museum of the Huacas de Moche  were selected from five graves and from one ceremonial context of the Uhle Platform , curated at the site Museum of El Brujo , were selected from four graves at El Brujo  and cattle (Bos Taurus) Bone and enamel form at different stages of an individual’s life and present different metabolic activities. Bone is constantly remodeled. Cogenetic bone collagen and structural carbonates remodel together and both provide a long-term isotopic signal. In humans, bone turnover varies between 10 to 30 years, depending on the age of the individual 18Obone and δ13Cbone values.Enamel and bone surfaces were mechanically cleaned to remove soft tissue, adherent soil or other contaminants by abrasion with a tungsten drill bit. Mechanical cleaning also detached the adherent cement on teeth and the outmost layer of bone, which is most susceptible to diagenetic contaminants. Cleaned bone samples were hand ground using an agate mortar and pestle and passed through a series of sieves. The finer fraction (<300 µm) was selected for determining δCrown height was measured for each tooth and the highest lobe was selected for sampling. Sequential sampling perpendicularly to the crown growth axis, from the apex to the enamel-dentine junction, was performed using a diamond drill bit. For El Brujo and modern camelid molars, each sample was a 1-mm-wide groove, taken from the buccal side through the whole thickness of the enamel layer . Uhle Pl−1) and 1M acetic acid , respectively, due to the higher susceptibility of bone to diagenetic contamination. The acetic acid treatment was used to remove exogenous carbonate and was carried out on both archaeological and modern specimens to ensure consistency when comparing results. All samples were then rinsed at least five times and oven-dried at 50°C. Bioapatite samples weighing 600 µg were reacted with 100% phosphoric acid at 70°C for 4 min in a Kiel IV device, interfaced with a Delta V Advantage isotope ratio mass spectrometer. Analytical precision was ±0.03 ‰ for δ13C (1σ) and ±0.05 ‰ for δ18O (1σ), based on the repeated analysis of an internal calcite standard (Marble LM), previously calibrated against NBS-19.Bone organic matter was eliminated using a NaOCl (2–3%) treatment. Then, both enamel and bone powder samples were purified with 0.1 M acetic acid , following Longin’s 13C and δ15N analysis. Analytical error was estimated to be 0.34 ‰ for δ13C and 0.02 ‰ for δ15N, based on replicate analysis of the international standard IAEA 600.Bone collagen samples (500 µg) were combusted using an Elemental Analyser Flash 2000, coupled with a Delta V Advantage (Thermo Scientific) isotope ratio mass spectrometer for δ13Ccol and δ15Ncol values remain constant until bone collagen yields fall to less than 1% of the total bone mass 13C and δ18O for bone values, they can be compared with the bone collagen yields to assess the influence of collagen loss on structural carbonate. δ13C values of bone structural carbonates can also be compared to those of bone collagen. In herbivores, the spacing (Δδ13Cbone-col) between the two tissues is 7.6±0.5 ‰ 18Oenamel and δ13Cenamel values The atomic C:N ratio, the carbon and nitrogen content, as well as the yield of collagen, are indicators that can be used to assess potential diagenetic alterations or contaminations of bone collagen. The atomic C:N ratio of unaltered bone collagen ranges from 2.9 to 3.6 13C and δ15N values are used for investigating past diet because 1) there is a direct relationship between the values of an animal’s tissues and that of its food 13C values of bone collagen (δ13Ccol) are generally 5‰ higher compared to those of consumed plants 13Cbone or δ13Cenamel values represent an average carbon input into the whole diet 13C (2–3 ‰) over bone apatite Measurements of δ13C values between plants using the C3  and C4 (Hatch-Slack) photosynthetic pathways 13C values 3 pathways but rely on dissolved inorganic instead of atmospheric CO2 and also have intermediate δ13C values. Many factors can affect the δ13C value of terrestrial plants, such as the canopy effect, water availability and soil salinity  13C linked to altitude – is not clear. In contrast with this negative relationship between vegetation δ13C values and elevation, a positive correlation was found in northern Peru 4 plants increases with the decrease of altitude and the puna is nearly devoid of C4 plants. Besides, the upper limit for maize cultivation ends at about 3,500 masl and puna crops are limited to C3 plant species. The altitudinal distribution of C4 plants is linked to temperature, sunlight and precipitation. Thus, the highlands can be characterized as an exclusively C3 plant habitat type and camelids are expected to present a pure C3 plant diet. Camelids grazing at low elevations have increased access to wild C4 plants or could have been fed C4 crops. C4 plant and mixed C3/C4 plant diets thus indicate that camelids were raised in the lowlands or intermediate lands. Nevertheless, because the many C3 plants that grow on the coast could have potentially provided fodder – various non-maize crops, pods or leaves –, a camelid with a pure C3 diet did not necessarily originate from the highlands. Finally, potential access to marine resources in the lowlands could also influence camelid δ13C values.The existence of geographic variations in isotopic values potentially enables us to distinguish whether camelids found in coastal sites were raised locally or in the highlands. Natural variations in δcamelids . A posit13Ccol values of –19.2±0.2 ‰ were measured for domestic camelids in southern Peru 13Cbone values of –12.0±0.4 ‰ were measured at La Raya (Peru) 13C values –were corrected by 1.5 ‰ to adjust for the Suess effect 13C values of pure C3 and pure C4-feeders can be predicted from the δ13C values of pre-industrial C3 and C4 plants and used to determine the proportions of C3 and C4 in the diet of archaeological specimens. The mean δ13C for pre-industrial C3 and C4 plants is estimated to be ∼–26 ‰ by correcting the average value of modern plants for fossil fuel effect (∼1.5 ‰). Szpak et al. 13C value of –10.3 ‰ to be appropriate for human palaeodietary models in the Central Andes. However, kernels are consumed by humans whereas the leaf was more likely to be consumed by camelids. A mean leaf value of –11.4 ‰, which is similar to the average values of wild C4 plants, thus appears more appropriate for camelid dietary studies. Using the +14 ‰ bioapatite-diet spacing and a collagen-diet spacing of 5 ‰, a C3 plant-based diet therefore results in an average δ13Cenamel of ∼–12 ‰, δ13Cbone of ∼–14 ‰ and a δ13Ccol of ∼–21‰. The mean δ13C of pre-industrial C4 plants is estimated to be ∼–11.5 ‰ and a pure C4-diet should result in an average δ13Cenamel of∼ +2.5 ‰, δ13Cbonel of 0 ‰ and a δ13Ccol of –6.5 ‰. The estimated δ13C values of pure C3 and pure C4-feeders were used as end-members in a simple mixing model for calculating the proportion of C4 in the diet of archaeological camelids .Mean δcamelids –2. Howev15N values are expected for domestic camelids feeding extensively on coastal or low-altitude forage, due to the consumption of terrestrial plants with relatively high δ15N values and the potential intake of marine resources 15N values were negatively correlated with altitude and mean annual precipitation along an altitudinal transect of the Moche Valley. The magnitude of difference between animals feeding on wild plants at lower (and drier) altitudes and animals feeding at higher (and wetter) altitudes has been estimated to be 4–6 ‰ 15Ncol values compared to modern puna camelids, suggesting that plants characterized by high δ15Ncol values can be naturally selected by wild camelids.Higher δ18O values of structural carbonate in bone and tooth enamel reflect the δ18O value of body water at body temperature. Body water oxygen comes mostly from drinking water and from food, and to a lesser extent from the atmosphere via inhalation, with a predictable fractionation 18O values of ingested water (δ18Od w) to the δ18O values of structural carbonate and phosphate phases of enamel have been developed in the literature. In this study, we used two equations (Eq. 1) The δ18Obone and δ18Oenamel values measured in pre-Hispanic remains can be compared to those of modern δ18O values for environmental water (δ18Oe w) for assessing an animal’s movement to different geographical areas and estimating the place of residence 18O values of meteoric water (δ18Om w) are theoretically transferred and retained in the body of living organisms, studies of modern precipitation provide some of the necessary baseline data for residential mobility studies 18Om w values are governed by the amount of rainfall, altitude, latitude, distance from the coast and temperature 16O during evaporation and the progressive loss of 18O during precipitation as air masses move inland and upwards 18Om w values, which tend to vary predictably across a landmass such as the Andean region in relation to local topography 18Om w is limited in the Central Andean region. Preliminary data obtained on an altitudinal transect along the Moche Valley indicate a difference as high as 14 ‰ between the coast and the highlands  . δ18Om w values for a specific geographical location can be estimated using the Online Isotopes in Precipitation Calculator (OPIC Version 2.2: http://www.waterisotopes.org/). This calculator takes into account the geographic location  to model the annual and monthly variations in δ18Om w for the entire globe 18Om w values, which are limited in the case of the Andes. OPIC predicted mean annual δ18Om w values are –11.8 ‰  and –12.8 ‰  for the puna of Tocra and Quiruvilca, respectively, and –4.8 ‰  for the coastal region of the modern city of Trujillo (−7°99′S).Basic Andean environmental trends do not seem to have changed over the past 2,000 years see . δ18Obon18O values of environmental water (δ18Oe w) are not solely tied to rainfall values, which complicates their use 18Oe w values within regions that may in fact exceed differences between regions 18Oe w values in the Central Andes have been reported to range from –6 to –3 ‰ on the coast, from –9 to –5 ‰ in the yunga (intermediate lands) and from –18 to –11 ‰ in the puna  do not ingest meteoric water but surface waters, or groundwater from wells. Environmental water comprises surface waters  and groundwater. The δ18Oe w and δ18Om w values, higher aridity and evaporation of surface water, camelids raised on the coast or at low altitudes should present higher δ18Obone and δ18Oenamel values than camelids raised in the highlands. Based on Eq. 1 and Eq. 2 and OPIC intra-annual variation in δ18Om w and IAEA/WMO δ18Oe w values, δ18Oenamel of animals living in the lowlands, yunga and puna can be predicted to vary from –5.8 to +0.5 ‰, –6.2 to –2.3 ‰ and –15 to –5.5 ‰, respectively. The enrichment of structural carbonate in enamel compared to that of bone structural carbonate has been estimated to be 1.7 ‰ in oxygen in pigs 18Oenamel to estimate δ18Obone values for animals living along the coast and in the yunga  to –8.9 ‰ (Areq-1), with mean tooth values ranging from –12.1±0.8 to –9.6±0.2 ‰  to 2.8 (M3 of UH-11). Maximum intra-individual variation is 3.3 ‰ for the three molars of UH-8. At El Brujo, δ13Cen values varied from –9.9 to –0.1 ‰ with mean tooth values varying from –8.1±0.2 to –1.4±0.4 ‰ (EBE1-1995). Intra-tooth variation ranged from 0.6 to 5.4 ‰ (EBT2-1995) while intra-individual variation was 4.7 ‰ for EBT2-1998 and 6.9 ‰ for EBE1-1995.For modern camelids, δ.6±0.2 ‰ –8. Intrapecimens –9–10. Fo18Oenamel values ranged from –10.1 (Areq-1) to –1.3 ‰ (Quiru-1), with mean tooth values ranging from –8.8±0.2 to –2.0±0.6 ‰  to 3.1 ‰ (EBT6-1994). Intra-tooth variation ranged from 0.3 to 2.8 ‰.Modern camelid δ.0±0.6 ‰ –8. Intraerlapped –9–10. U18Oenamel values  specimens. Archaeological camelids are discriminated from modern specimens by δ13C values measured in both organic and inorganic bone fractions. δ13Ccol and δ13Cbone values of modern specimens from the puna of Tocra  and Quiruvilca (Quiru-1) were consistent with predicted and previously measured values from the literature and all indicate the sole consumption of C3 plants  were higher.In the present study, the life history of Mochica archaeological camelids was reconstructed through the analysis of the stable isotope composition of bone and enamel and comparisons with modern highland  and from an adult (UH-8), their δ13Cenamel values were very similar to those of modern puna camelids , except for one adult from El Brujo (EBE1-1995), for which the C4 contribution increased by 50% between the second and third years of life  from Quiruvilca exhibited higher δ18Oenamel values than predicted values  that might have moved to a habitat characterized by lower δ18Oe w values or less arid conditions, probably at a higher altitude.The analysis of tooth enamel reveals more diverse and complex life histories for Mochica camelids than bone analysis. Whereas all the modern specimens had a pure C4 to 73% ; Fig. 7.camelids , Fig. 6. of life , Fig. 11d values , Fig. 7.puna all their life, as shown by the incorporation of C4 plants. However, the comparison between these two tissues also identified an ontogenetic switch in diet and possible residential mobility throughout life for three animals from the Uhle Platform . This ontogenetic switch indicates a pure  C3 diet during the first year of life, followed by a mixed C3-C4 plant diet afterwards. A pure C3 diet alone is not indicative of the animal’s geographic origin because C3 plants dominate in all habitats. Many C3 species that thrive on the coast could have potentially provided fodder – various non-maize crops, shrub leaves or pods − for camelids. Prosopis sp. remains have been reported from camelid coprolites dated of the Chimú Period 18Oenamel values for the two youngest camelids . Regarding the adult specimen (UH-8), the arid signal exhibited in the M1 δ18Oenamel values  suggests that this animal was bred in the lowlands where it switched diet during the second year of life . Furthermore, all juveniles were present locally at least several months before slaughtering. The probable pure C3 diet during early life for two young individuals from Uhle Platform (UH-4 and UH-7) raises questions concerning their geographic origin. These individuals could have either been raised locally or in the highlands. If so, they would have subsequently reached the coast during trips for product exchanges  between ecological zones. Although young individuals are not considered robust enough to carry large burdens during such trips Despite the importance of domestic camelids in the Mochica culture, management strategies and pastoralism remain poorly documented. In the present study, adults and juveniles of more than 1 year were analysed. Combined isotopic measurements of bone and tooth enamel clearly showed that all the adults and most juveniles spent their all life outside the puna during the Mochica period but also that of gregarious adult females. The latter do not travel during the gestation period, which lasts from eleven to twelve months At both El Brujo and Uhle Platform, animals used for funerary and ritual purposes were kept in the lower part of the valleys. Local herds were maintained both for slaughtering purposes and reproduction, as indicated by demographic data based on the study of archaeozoological remains and domestic camelid ethology Lomas are present close to Cerro Campana, between the Moche and Chicama valleys, and can be considered as a potential herding location, at least during the austral winter, as suggested for other sites in Peru 4 plants are relatively rare and high δ13Ccol (or δ13Cbone) values, such as those recorded at the Middle Horizon Wari-affiliated site of Conchopata 4 species, such as the saltgrass grama salada (Distichlis spicata), can locally form relatively large patches and pastures where herders could have taken their animals. C3 plants nevertheless dominate the Peruvian flora and it could be difficult for herders to find wild C4 pastures capable of contributing as much as 50–70% of the diet of some camelids. Maize but also marine algae can supplement the diet of wild or domestic herds 13Ccol and δ15Ncol values measured at the coastal sites of central and south Peru of La Paloma and Chilca were interpreted as lowland breeding, on the arid coast itself 15N values for marine plants compared to terrestrial plants 15Ncol values of archaeological camelids. Marine algae have a mean δ13C value of –15.0 ‰ 13Ccol and δ13Cbone values. Although this high proportion of marine algae seems unlikely, they may still have contributed to the camelid diet, along with C4 plants. This hypothesis cannot be ruled out by the isotopic tracers used in the present study.Camelid management outside the modern geographical range has been documented for middle valley areas in Andean regions where richer pasturelands are available and foddering might have been practiced during pre-Hispanic times 18Oenamel and δ18Obone values, but they might nevertheless provide insights into herding practices. A negative trend in the relationship between δ13Cenamel and δ18Oenamel values is observed when all archaeological teeth are considered, suggesting that there is no connection between aridity and dietary signals  grown at various altitudes from the arid coast to intermediate lands. Cultivation on the coast is rendered possible by the presence of irrigation networks supplied by rivers from the Andes, which have different δ18Oe w values from those predicted at local altitudes, as well as different precipitation rates and temperatures. The control of drinking by the herders is not only suggested by the absolute δ18Oenamel values, but also by the difference in the shape of isotopic intra-tooth profiles between archaeological and modern specimens. The two modern adult alpacas (Areq-1 and Quiru-1) were raised on natural puna pastures all year around, without fodder, and widescale geographic movement over throughout life. The intra-tooth cyclic variation in δ18Oenamel recorded in their M3 is linked to seasonal variation in temperature and δ18Oe w values 18Oenamel intra- tooth cyclic variations, independently of the proportion of C4 plants in their diet , but also that drinking water was not affected by seasonal variations, such as natural surface water and precipitation, but came from controlled sources such as wells or canals.The geographical origin of camelids appears difficult to assess from δ signals . A positeir diet –10. The puna. As the Mochica polities exerted their political and social power at the scale of the valleys, the provisioning of domestic camelids might also have been organized at this level. All animals were bred in the lowlands but had different life histories, with the exception of the three specimens  recovered from the same ceremonial context (Element 21) at the Uhle Platform. They shared similar trends in life histories despite differences in age and may represent a single ritual event  fields or at different elevations in the valleys. Maize played a key role in the political economy and has constituted a primary component of the diet of diverse Andean polities and cultures from at least the late Archaic al event . Part ofThe present study underlines the adaptive capacities of the Mochica people to their environment. Irrigation allowed for the development of extensive agriculture in a very arid environment. Herders also adapted their practices to this difficult environment. This study also emphasizes the role of maize in different aspects of Mochica economic life. Further work will be conducted on Mochica camelids from different valleys to confirm these first results and to compare herding practices on a regional scale. Strong relationships might have been established between two major religious centers, such as the Huacas de Moche and El Brujo, and their hinterlands. A better understanding of these relationships is required in order to describe how herd management was spatially organized. Camelids from domestic contexts should also be analysed to compare them with camelids from ritual contexts, to determine whether or not they have the same origin and to gain insights into meat exchange in the different Andean ecozones. Our study also indicates that diversity in herding practices existed in the lowlands, as already described for higher altitudes, even though only animals with similar functions  were analysed. Species-specific identification of llamas and alpacas was not possible from the osteological study of archaeological remains. This would, however, provide a better understanding of the relation between camelid functions and herding practices.18Oenamel values provide some information but inferences are limited so far because the environmental and biological factors that might influence δ18Oenamel values need to be better understood. The influence of the circulation of surface water that might mask the difference in δ18Oe w values between ecological zones, breastfeeding and milk consumption are some of the factors that have to be documented. The duration of tooth mineralization in domestic camelids would also need to be determined. Finally, a more precise reconstruction of the geographic location of pastureland and mobility is expected from the combination of the measurement of δ13C, δ15N and δ18Oenamel values with 87Sr/86Sr values.An increasing number of studies have used stable isotopic analyses to document camelid diet and herding practices in Peru, Chile and Argentina, during the pre-Hispanic period


A registry-based analysis revealed imprecise informal one-tiered trauma team activation (TTA) in a primary trauma centre. A two-tiered TTA protocol was introduced and analysed to examine its impact on triage precision and resource utilization.Interhospital transfers and patients admitted by non-healthcare personnel were excluded. Undertriage was defined as the fraction of major trauma victims (New Injury Severity Score over 15) admitted without TTA. Overtriage was the fraction of TTA without major trauma.P < 0·001) after system revision. Overall overtriage increased from 61·5 to 71·6 per cent, whereas the mean number of skilled hours spent per overtriaged patient was reduced from 6·5 to 3·5 (P < 0·001) and the number of skilled hours spent per major trauma victim was reduced from 7·4 to 7·1 (P < 0·001). Increasing age increased risk for undertriage and decreased risk for overtriage. Falls increased risk for undertriage and decreased risk for overtriage, whereas motor vehicle-related accidents showed the opposite effects. Patients triaged to a prehospital response involving an anaesthetist had less chance of both undertriage and overtriage.Of 1812 patients, 768 had major trauma. Overall undertriage was reduced from 28·4 to 19·1 per cent . Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.A two-tiered TTA protocol was associated with reduced undertriage and increased overtriage, while trauma team resource consumption was reduced. Registration number: NCT00876564 (Effective system to deal with local and distant trauma Early recognition of major trauma enables emergency medical services (EMS) to accurately triage and transport injured patients to an appropriate hospital. Field triage, however, remains a challenge due to occult injuries, the unpredictable evolution of symptoms and complexities of evaluating patients in difficult circumstances. A combined literature review and US national expert panel consensus resulted in ‘Guidelines for Field Triage of Injured Patients’Norway is sparsely populated with weather-dependent and time-consuming patient transport. Some 50 Norwegian hospitals receive patients with major injuries, most with low admission ratesIf patients with major injuries are deprived access to the possible benefits of immediate resuscitation and expert evaluation provided by a trauma team (undertriage), avoidable deaths may occurTableSUH is a 630-bed primary trauma centre for a mixed rural/urban population of approximately 330 000 inhabitants and the trauma referral centre for an additional 120 000 people living in Rogaland county in southwestern Norway. The hospital admits each year approximately 140 adult and paediatric patients with a New Injury Severity ScorePrehospital emergency care in the SUH catchment area is provided by on-call general practitioners, vehicle ambulance units staffed by paramedics and emergency medical technicians, and anaesthetist-manned rapid response cars and helicoptersTableTableThe Rogaland Trauma System Study Group was established by SUH in 2008 in cooperation with the Norwegian Air Ambulance Foundation research department. The group comprised clinical representatives from the emergency department, dispatch, surgery, anaesthesiology, and ground and air ambulance units in addition to researchers. They developed guidelines on field triage and TTA based on available evidenceThe trauma registry was upgraded to prospectively collect data necessary to compare practice after introduction of the two-tiered guidelines. The guidelines were launched on 3 February 2009 under the direction of the Rogaland Trauma System Study Group. Throughout the implementation period, instructors addressed specific aspects of the system revision during educational outreach visits. Information posters and periodical newsletters were used to increase understanding and awareness of the system revision.The trial was designed as a prospective interventional study utilizing SUH trauma registry data and was divided into an analysis of the ‘before’ period, which consisted of patients subject to the informal one-tiered practice (1 January 2004 to 31 December 2008), and an analysis of the ‘after’ period, which consisted of patients subject to the two-tiered TTA protocol (1 July 2009 to 31 December 2010). The implementation period (1 January 2009 to 30 June 2009) was excluded from the analysis.Tablea, b and c). The AIS 1998 catalogue was used for all patientsConsecutive patients admitted to SUH during the study period who were registered in the SUH trauma registry and assigned one or more AIS codes were included if they had major trauma (NISS over 15) and/or had been triaged to meet the trauma team . The Norwegian Social Science Data Services approved access to aggregate anonymous data on relevant patients in the hospital-based trauma registry (20 840 KS/LR). The study was registered in clinicaltrials.gov (NCT00876564).d in TableTablePatients were classified as major trauma victims if they had an NISS above 15TableIn addition to direct comparison of overtriage rates ‘before’ and ‘after’ system revision, skilled hours' expenditure on overtriage per major trauma victim was measured. For each member of the trauma team, 30 min per unnecessary activation was allocated  methodologyU test. Assumed predictors of overtriage and undertriage were tested in a multiple logistic regression analysis. All data were analysed using STATA/SE™ version 10.1  and StatView version 5.0.1 . Statistical significance was assumed for P < 0·050.Categorical variables were compared with Fisher's exact test, whereas continuous variables were analysed using the Mann–Whitney During the study period (1 January 2004 to 31 December 2010), 2327 patients were entered in the SUH trauma registry. Some 364 injured patients who were transferred to SUH from other hospitals, admitted by non-healthcare personnel or admitted during the new TTA criteria implementation period (1 January 2009 to 30 June 2009) were excluded. A further 151 patients who had neither sustained major trauma nor been triaged to a trauma team (true-negatives) were also excluded. In total, 1812 patients met the inclusion criteria and were enrolled in the study. There was a missing probability of survival for seven patients and lack of documentation of TTA criteria in 123, but otherwise data were complete.Tableversus blunt injuries did not change significantly between the two study periods.In the ‘after’ period, there was a significant increase in the proportion of traumas due to falls. The proportion of patients who met an anaesthetist before hospital decreased significantly and a higher proportion of the included patients had been triaged to receive a full or reduced trauma team. Median NISS score, proportion of patients with major trauma and number of deaths in ‘after’ patients were significantly lower.TableTriage categories of included patients are shown in P < 0·001). There was a 41·2 per cent relative reduction in undertriage rate in responses without anaesthetists, whereas the decrease in the low rate of undertriage performed by prehospital anaesthetists was not significant.In the ‘before’ period, 166 of the 585 patients with major trauma (28·4 per cent) were not triaged to a trauma team, and this fell to 35 of 183 (19·1 per cent) in the ‘after’ period (P < 0·001). The increase was most pronounced in prehospital responses with an anaesthetist, although responses without anaesthetists still had the highest rate (TableThe proportion of patients triaged to a trauma team who had not suffered major trauma increased from 670 of 1089 (61·5 per cent) in the ‘before’ study period to 374 of 522 (71·6 per cent) in the ‘after’ period (P < 0·001)  compared with 124 of 232 (53·4 per cent) in patients triaged to receive full teams (P < 0·001), whereas the number of skilled hours spent per major trauma victim was reduced from 7·4 to 7·1 (P < 0·001).The mean number of skilled hours spent per overtriaged patient was reduced from 6·5 to 3·5  and study period (‘after’ versus ‘before’). Results are shown in TableAfter initially finding an association between age and mistriage . The median age of patients who died was 80 (range 66–90) years and median NISS 46 (range 27–59). All had falls. For the total population of included patients, the W statistic (excess survivors per 100 patients compared with TRISS model predictions) did not change significantly: 2·123 (95 per cent c.i. 1·070 to 3·177) ‘before’ versus 2·510 (1·127 to 3·892) ‘after’.No deaths were registered in patients triaged to reduced teams. Median time from activation of reduced team to full team upgrade for the five affected patients was 11 (range 0–21) min. Median NISS was 17 (range 6–50), and one upgraded patient died. There were 12 deaths among undertriaged patients, eight (4·8 per cent) in the ‘before’ and four (11 per cent) in the ‘after’ study period (The present study found that the introduction of a formalized TTA protocol with a two-tiered response was associated with reduced undertriage and increased overtriage. Trauma team resource consumption was significantly reduced. For the study period as a whole, increasing age and falls increased risk for undertriage and decreased risk for overtriage, whereas motor vehicle-related accidents showed the opposite effects.Triage precision before implementation of the TTA protocol was poor. Informal activation of trauma teams did not correctly identify victims of major trauma. A relative reduction in overall undertriage of 32·6 per cent followed system revision. The current undertriage rate of 19·1 per cent is still considered unacceptable and continued efforts to further improve triage precision are essential. The death of one upgraded patient with an NISS of 50 emphasizes that the practice of upgrading a reduced team to a full team requires constant monitoring. There was a highly significant 41·2 per cent relative reduction in undertriage in prehospital responses without an anaesthestist but only a non-significant trend towards less undertriage when an anaesthetist was present. When studied in the logistic regression model, prehospital responses involving an anaesthetist had a higher overall triage precision with reduced risk for undertriage as well as overtriage. In the Norwegian prehospital system, anaesthetist-manned units normally attend patients considered severely injured by either dispatch or paramedic-manned units already at the scene, whereas paramedics respond to a considerably less preselected patient population. Direct comparison between the two EMS provider categories was therefore considered both unreasonable and counterproductive.This undertriage rate in responses without an anaesthestist remains high, but is also seen in other organized trauma systemset al.All 12 patients who died in the undertriaged group were over 66 years old and had falls. The logistic regression model showed that increasing age and falls were both found to increase risk for undertriage and decrease risk for overtriage. Velmahos It was expected that a reduction in undertriage would be accompanied by increased overtriage. Although TTA is beneficial for trauma victims, it may lead to suboptimal care for other patientsMuch emphasis has been put on mechanism of injury as a criterion for TTAet al.The present study has a number of limitations. The ‘before’ study period involved a review of trauma registry data restricted to variables already defined in the trauma registry. Missing documentation of TTA criteria remained a challenge throughout the study period. A short 18-month ‘after’ period compared with a 60-month long ‘before’ period increases the risk for type II errors. The study is also susceptible to the Hawthorne effectImplementation of system revisions can be a challenging enterprise with over 250 barriers identified in the literatureConverting from an informal one-tiered TTA to a formalized two-tiered TTA lowered the threshold for immediate access to high-quality trauma care by reducing undertriage rates. Although the introduction of a reduced trauma team increased the overtriage rate, the number of work hours spent per major trauma victim was reduced.