Incidence of Acute Rejection Compared With Endomyocardial Biopsy Complications for Heart Transplant Patients in the Contemporary Era.

BACKGROUND: The reference standard of detecting acute rejection (AR) in adult heart transplant (HTx) patients is an endomyocardial biopsy (EMB). The majority of EMBs are performed in asymptomatic patients. However, the incidence of treated AR compared with EMB complications has not been compared in the contemporary era (2010-current). METHODS: The authors retrospectively analyzed 2769 EMBs obtained in 326 consecutive HTx patients between August 2019 and August 2022. Variables included surveillance versus for-cause indication, recipient and donor characteristics, EMB procedural data and pathological grades, treatment for AR, and clinical outcomes. RESULTS: The overall EMB complications rate was 1.6%. EMBs performed within 1 mo after HTx compared with after 1 mo from HTx showed significantly increased complications (OR, 12.74, P < 0.001). The treated AR rate was 14.2% in the for-cause EMBs and 1.2% in the surveillance EMBs. We found the incidence of AR versus EMB complications was significantly lower in the surveillance compared with the for-cause EMB group (OR, 0.05, P < 0.001). We also found the incidence of EMB complications was higher than treated AR in surveillance EMBs. CONCLUSIONS: The yield of surveillance EMBs has declined in the contemporary era, with a higher incidence of EMB complications compared with detected AR. The risk of EMB complications was highest within 1 mo after HTx. Surveillance EMB protocols in the contemporary era may need to be reevaluated.

Benefit versus Risk of Endomyocardial Biopsy for Heart Transplant Patients in the Contemporary Era.

Background: The reference standard of detecting acute rejection (AR) in adult heart transplant (HTx) patients is an endomyocardial biopsy (EMB). The majority of EMBs are performed in asymptomatic patients. However, the benefit of diagnosing and treating AR compared to the risk of EMB complications has not been compared in the contemporary era (2010-current). Methods: The authors retrospectively analyzed 2,769 EMB obtained in 326 consecutive HTx patients between August 2019 and August 2022. Variables included surveillance versus for cause indication, recipient and donor characteristics, EMB procedural data and pathologic grades, treatment for AR, and clinical outcomes. Results: The overall EMB complication rate was 1.6%. EMBs performed within 1 month after HTx compared to after 1 month from HTx showed significantly increased complications (OR = 12.74, p < 0.001). The treated AR rate was 14.2% in the for cause EMBs and 1.2% in the surveillance EMBs. We found the benefit/risk ratio was significantly lower in the surveillance compared to the for cause EMB group (OR = 0.05, p < 0.001). We also found the benefit to be lower than risk in surveillance EMBs. Conclusions: The yield of surveillance EMBs has declined, while for cause EMBs continued to demonstrate a high benefit/risk ratio. The risk of EMB complications was highest within 1 month after HTx. Surveillance EMB protocols in the contemporary era may need to be re-evaluated.

Comparison of two donor-derived cell-free DNA tests and a blood gene-expression profile test in heart transplantation.

BACKGROUND: Donor-derived cell-free DNA (dd-cfDNA) testing is an emerging screening modality for noninvasive detection of acute rejection (AR). This study compared the testing accuracy for AR of two commercially available dd-cfDNA and gene-expression profiling (GEP) testing in heart transplant (HTx) recipients. METHODS: This is a retrospective, observational study of HTx only patients who underwent standard and expanded single nucleotide polymorphism (SNP) dd-cfDNA between October 2020 to January 2022. Comparison with GEP was also performed. Assays were compared for correlation, accurate classification, and prediction for AR. RESULTS: A total of 428 samples from 112 unique HTx patients were used for the study. A positive standard SNP correlated with the expanded SNP assay (p < .001). Both standard and expanded SNP tests showed low sensitivity (39%, p = 1.0) but high specificity (82% and 84%, p = 1.0) for AR. GEP did not improve sensitivity and showed worse specificity (p < .001) compared to standard dd-cfDNA. CONCLUSION: We found no significant difference between standard and expanded SNP assays in detecting AR. We show improved specificity without change in sensitivity using dd-cfDNA in place of GEP testing. Prospective controlled studies to address how to best implement dd-cfDNA testing into clinical practice are needed.

Net energy prediction and energy efficiency of feed for broiler chickens.

Global consumption of chicken meat has increased at a faster rate than any other animal protein source, and thus refinements in energy formulation techniques for feed have continued to gain importance. Formulation of animal feed based on net energy (NE) has been implemented in ruminants and pigs but not in poultry. A closed-circuit respiratory calorimetry system was employed on 25- to 28-day-old broilers fed 19 diets formulated with varying nutrient composition to produce equations to predict NE and apparent metabolizable energy (AME) efficiency of feed for broiler chickens. Performance, energy and N balance, respiratory quotient, and energy utilization were measured in the birds. Linear regression analysis was performed to generate prediction equations for dietary energy content and AME efficiency. The NE content was positively related to AME and ether extract, but negatively to crude protein. The study generated equations that can accurately predict NE, and NE/AME using AME value and chemical composition of feeds. The NE prediction equations were further validated on a separate set of diets with high correlation (r = 0.99) and accuracy. The outcomes are an important step for the broiler industry to adapt to an NE system in place of AME systems for the formulation of broiler chicken feeds following robust validation experiments.

Dynamics of intestinal metabolites and morphology in response to necrotic enteritis challenge in broiler chickens.

Despite the relatively small contribution to metabolizable energy that volatile fatty acids (VFAs) provide in chickens, these organic acids have been reported to play beneficial roles in the gastrointestinal tract (GIT) of birds, for example, inhibition of the growth of some pathogenic bacteria. However, information regarding the dynamics of these metabolites in the GIT of chickens is still scarce, especially under disease conditions such as necrotic enteritis (NE). Here, we investigated the dynamics of VFAs and lactic acid, and intestinal morphology in response to NE predisposing factors, that is, excessive dietary fishmeal and Eimeria inoculation, and causative agent Clostridium perfringens producing NetB toxin. The experiment was designed in a 2 × 2 × 2 factorial arrangement of treatments with or without: fishmeal feeding, Eimeria inoculation and C. perfringens challenge. The results showed that these factors significantly influenced composition and concentration of VFAs and lactic acids, pH and histomorphometry in one way or another. These changes may be important for the onset of NE or only the synergetic responses to micro environmental stress. Eimeria appeared to be more important than fishmeal in predisposing birds to NE, thus the application of Eimeria in NE challenge provides more consistent success in inducing the disease. The metabolic responses to various adverse factors such as excessive dietary fishmeal and Eimeria infection are complex. Thus, intensive efforts are required to better understand NE so as to achieve the control of the disease in the absence of antibiotics.

A Multifactorial Analysis of the Extent to Which Eimeria and Fishmeal Predispose Broiler Chickens to Necrotic Enteritis.

Necrotic enteritis (NE) is an important infectious disease in chickens. Predisposing factors play critical roles both in disease outbreaks in the field and in models for experimental induction of disease. Systematic manipulation and study of predisposing factors help to optimize methods for the experimental reproduction of disease. The nature of such factors may play a confounding role in challenge models and, therefore, warrant investigation to determine their importance in industry-relevant NE reproduction models. In the present study, we examined the roles of dietary fishmeal inclusion, Eimeria inoculation (E), and Clostridium perfringens challenge (C) on broiler growth performance and induction of NE infection. The results showed that E, preceding C, greatly increased the severity of NE induced in broiler chickens, but fishmeal addition played only a marginal role in the challenge model. Bird performance was significantly affected by all three factors during the 35-day experimental period. Fishmeal increased body weight, but statistically significant effects of fishmeal were not observed on feed conversion ratio (FCR) and feed intake. Both Eimeria and C. perfringens significantly reduced body weight gain and feed intake. E but not C led to significantly poorer FCR. These findings indicate that dietary fishmeal may be removed from the model to allow the performance results of challenged chicks to be equivalent to the performance of chicks in the field. In conclusion, the present study demonstrates that an NE challenge model without fishmeal is valid and removes bird performance bias in the model introduced by feeding high fishmeal diets, refining the model to facilitate the yield of more commercially relevant results.

Differential responses of cecal microbiota to fishmeal, Eimeria and Clostridium perfringens in a necrotic enteritis challenge model in chickens.

Clostridium perfringens causes enteric diseases in animals and humans. In poultry, avian-specific C. perfringens strains cause necrotic enteritis, an economically significant poultry disease that costs the global industry over $2 billion annually in losses and control measures. With removal of antibiotic growth promoters in some countries this disease appears to be on the rise. In experimental conditions used to study disease pathogenesis and potential control measures, reproduction of the disease relies on the use of predisposing factors such as Eimeria infection and the use of high protein diets, indicating complex mechanisms involved in the onset of necrotic enteritis. The mechanisms by which the predisposing factors contribute to disease progression are not well understood but it has been suggested that they may cause perturbations in the microbiota within the gastrointestinal tract. We inspected changes in cecal microbiota and short chain fatty acids (SCFA) induced by Eimeria and fishmeal, in birds challenged or not challenged with C. perfringens. C. perfringens challenge in the absence of predisposing factors did not cause significant changes in either the alpha or beta diversity of the microbiota nor in concentrations of SCFA. Moreover, there was no C. perfringens detected in the cecal microbiota 2 days post-challenge without the presence of predisposing factors. In contrast, both fishmeal and Eimeria caused significant changes in microbiota, seen in both alpha and beta diversity and also enabled C. perfringens to establish itself post challenge. Eimeria had its strongest influence on intestinal microbiota and SCFA when combined with fishmeal. Out of 6 SCFAs measured, including butyric acid, none were significantly influenced by C. perfringens, but their levels were strongly modified following the use of both predisposing factors. There was little overlap in the changes caused following Eimeria and fishmeal treatments, possibly indicating multiple routes for progressing towards clinical symptoms of necrotic enteritis.

Two necrotic enteritis predisposing factors, dietary fishmeal and Eimeria infection, induce large changes in the caecal microbiota of broiler chickens.

It is widely established that a high-protein fishmeal supplemented starter diet and Eimeria infection can predispose birds to the development of clinical necrotic enteritis symptoms following Clostridium perfringens infection. However, it has not been clearly established what changes these treatments cause to predispose birds to succumb to necrotic enteritis. We analysed caecal microbiota of 4 groups of broilers (n=12) using deep pyrosequencing of 16S rDNA amplicons: (1) control chicks fed a control diet, (2) Eimeria infected chicks fed control diet, (3) chicks fed fishmeal supplemented diet and lastly (4) both fishmeal fed and Eimeria infected chicks. We found that the high-protein fishmeal diet had a strong effect on the intestinal microbiota similar to the previously reported effect of C. perfringens infection. We noted major changes in the prevalence of various lactobacilli while the total culturable Lactobacillus counts remained stable. The Ruminococcaceae, Lachnospiraceae, unknown Clostridiales and Lactobacillaceae families were most affected by fishmeal with increases in a number of operational taxonomic units (OTUs) that had previously been linked to Crohn's disease and reductions in OTUs known to be butyrate producers. Eimeria induced very different changes in microbiota; Ruminococcaceae groups were reduced in number and three unknown Clostridium species were increased in abundance. Additionally, Eimeria did not significantly influence changes in pH, formic, propionic or isobutyric acid while fishmeal induced dramatic changes in all these measures. Both fishmeal feeding and Eimeria infection induced significant changes in the gut microbiota; these changes may play an important role in predisposing birds to necrotic enteritis.

Real-time PCR assay for Clostridium perfringens in broiler chickens in a challenge model of necrotic enteritis.

We compared ileal Clostridium perfringens quantification results produced by real-time PCR and culture-based methods in broiler chickens in a challenge model of necrotic enteritis. Assessment of the relative standard deviations (RSDs) revealed that the real-time PCR assay generated a smaller standard deviation and thus was more precise than the culture-based method. Linear regression analysis indicated that the bacterial counts of these two methods were highly correlated (R(2) = 0.845). We suggest that real-time PCR could be a replacement of the culture method for quantifying C. perfringens in the intestinal tracts of broiler chickens.

Optimized necrotic enteritis model producing clinical and subclinical infection of Clostridium perfringens in broiler chickens.

In this study we assessed the roles of Eimeria infection and dietary manipulation (feeding a diet with a high level of fishmeal) in an Australian necrotic enteritis (NE) challenge model in broiler chickens. An experiment was designed to test the hypothesis that Eimeria infection and dietary manipulation, i.e., inclusion of fishmeal in the diet, are necessary to induce NE experimentally. The results showed that the combination of Eimeria administration and fishmeal feeding had a significant effect on induction of clinical and subclinical Clostridium perfringens infection. The majority of the mortality that occurred during the second week of the trial was due to an NE outbreak following the C. perfringens challenge. The mortality rate of the birds was 12.00% for the high-fishmeal (HFM; 500 g/kg) group and 9.33% for the low-fishmeal (LFM; 250 g/kg) group when the birds were subjected to C. perfringens and Eimeria. Fishmeal alone did not induce significant mortality in birds challenged only with C. perfringens but showed a significantly higher C. perfringens count than the non-fishmeal (NFM) control group. Eimeria administration had a significant effect on NE-related mortality but did not have an effect on the C. perfringens count. In accordance with the time course of bird mortality, it can be determined that of the 3 successive days of oral gavage with C. perfringens, the first inoculation was essential for inducing NE, but the third had no additional effect on NE-related mortality. Also, reducing the fishmeal level from 500 to 250 g/kg had no negative impact on the reproducibility of the model. It may be concluded that NE can be consistently induced under experimental conditions by feeding broilers a diet containing 250 g/kg fishmeal, using a single inoculation with low numbers of Eimeria, administering one or two oral C. perfringens inoculations, and maintaining appropriate ambient temperatures and diets.

Erythema nodosum associated with diffuse, large B-cell non-Hodgkin lymphoma detected by FDG PET.

A patient is described with non-Hodgkin lymphoma and erythematous skin nodules suspected to be erythema nodosum. The patient underwent serial fluorodeoxyglucose (FDG) positron emission tomography (PET), which demonstrated normalization of FDG uptake by the lymphoma after 2 cycles of chemotherapy, but there was new abnormal uptake involving the subcutaneous tissues of the lower extremities. A typical skin lesion was sampled and showed the appearance of erythema nodosum with no evidence of lymphoma. The FDG uptake gradually diminished on serial PET imaging after treatment with nonsteroidal antiinflammatory drugs. In view of the recognized association of erythema nodosum with malignancy and the differential rate of response to chemotherapy, the lesions of erythema nodosum may be a source of a false-positive PET interpretation, and histologic assessment should be considered.