Lymphatic endothelial cell immunohistochemical markers for evaluation of the intestinal lymphatic vasculature in dogs with chronic inflammatory enteropathy

Primary small intestinal lymphangiosarcoma in a dog presenting with a segmental partial mesenteric volvulus

A 3-year-old Great Dane presented with a history of chronic vomiting and diarrhoea. Abdominal computed tomography followed by exploratory laparotomy revealed a perforated, segmental partial mesenteric volvulus, affecting an abnormal section of distal jejunum, which was resected. Histopathology and immunohistochemistry results were consistent with jejunal lymphangiosarcoma. This case represents the first report of primary small intestinal lymphangiosarcoma in dogs and the importance of immunohistochemistry for definitive diagnosis.

Nomogram to predict feeding intolerance in critically ill children

Feed intolerance (FI) is significantly associated with poor prognosis in critically ill patients. This study aimed to understand the characteristics of children with FI and identify the factors predicting FI in critically ill children. This retrospective cohort study was conducted between January 2017 and June 2022 in the Pediatric Intensive Care Unit of a specialized children's hospital. Eighteen factors, including age, body mass index for age z-score (BAZ) < -2, paediatric index of mortality (PIM)3 score, Glasgow coma scale score, mechanical ventilation (MV), enteral nutrition delay, vasoactive drugs, sedatives, sepsis, heart disease, neurological disease, hypokalemia, arterial PH < 7.35, arterial partial pressure of oxygen (PaO2), blood glucose, hemoglobin, total protein, and albumin, were retrieved to predict FI. The outcome was FI during PICU stay. During the study period, a total of 854 children were included, of which 215 children developed FI. Six predictors of FI were selected: PIM3 score, MV, sepsis, hypokalemia, albumin, and PaO2. Multivariate logistic regression analysis showed that higher PIM3 score, MV, sepsis, hypokalemia, and lower PaO2 were independent risk factors for FI, whereas higher albumin was an independent protective factor for FI. The C-index of the predictive nomogram of 0.943 was confirmed at internal validation to be 0.940, indicating a good predictive value of the model. Decision curve analysis shows good clinical applicability of the nomogram in predicting FI.    Conclusion: The nomogram was verified to have a good prediction performance based on discrimination, calibration, and clinical decision analysis. What is Known: • Research has demonstrated that gastrointestinal (GI) dysfunction is not only a fundamental element of Multiple Organ Dysfunction Syndrome (MODS), but also the initiator of MODS. • Previous study has demonstrated a significant association between FI and poor prognosis in critically ill patients. What is New: • We excluded patients with primary gastrointestinal tract disease from our study, and we observed an incidence of FI of 25.2% in the Pediatric Intensive Care Unit (PICU). • Our study revealed that PIM3 score, MV, sepsis, hypokalemia, albumin, and PaO2 are significant predictors of FI.

Analysis of fecal microbial profiles in dogs with intestinal lymphangiectasia

Intestinal lymphangiectasia (IL) is a common complication in dogs. This study analyzed intestinal microbiota using 16S rRNA amplicon analysis as candidate factors that strongly influence the small intestinal lymphatic vessels in dogs with and without IL. Twelve dogs were included, of which six were diagnosed with lymphoplasmacytic enteritis, four with small-cell lymphoma, and two with large-cell lymphoma. Seven of these dogs had IL, whereas five did not. First, the microbial diversity analyzed by Faith pd index was significantly decreased in dogs with IL compared to dogs without IL. Then, the relative amounts of each bacterial taxa were compared between dogs with and without IL using Linear discriminant analysis effect size analysis. At the genus level, the Ruminococcus gnavus group significantly increased in dogs with IL compared to dogs without IL. A total of four genera, including Ruminococcus torques group and Faecalibacterium, which produce butyrate, significantly decreased in dogs with IL. This study showed decreased intestinal bacterial diversity and several alterations of intestinal microbiota, including a decrease in butyrate-producing bacteria in dogs with IL, compared to dogs without IL.

Pathophysiology, Diagnosis, and Management of Canine Intestinal Lymphangiectasia: A Comparative Review

Intestinal lymphangiectasia was first described in the dog over 50 years ago. Despite this, canine IL remains poorly understood and challenging to manage. Intestinal lymphangiectasia is characterized by variable intestinal lymphatic dilation, lymphatic obstruction, and/or lymphangitis, and is a common cause of protein-losing enteropathy in the dog. Breed predispositions are suggestive of a genetic cause, but IL can also occur as a secondary process. Similarly, both primary and secondary IL have been described in humans. Intestinal lymphangiectasia is definitively diagnosed via intestinal histopathology, but other diagnostic results can be suggestive of IL. Advanced imaging techniques are frequently utilized to aid in the diagnosis of IL in humans but have not been thoroughly investigated in the dog. Management strategies differ between humans and dogs. Dietary modification is the mainstay of therapy in humans with additional pharmacological therapies occasionally employed, and immunosuppressives are rarely used due to the lack of a recognized immune pathogenesis. In contrast, corticosteroid and immunosuppressive therapies are more commonly utilized in canine IL. This review aims toward a better understanding of canine IL with an emphasis on recent discoveries, comparative aspects, and necessary future investigations.

Relationship between serum cobalamin concentration and endoscopic ileal appearance and histology in dogs with chronic inflammatory enteropathy

Background

It has not been determined whether ileal appearance differs among dogs with chronic inflammatory enteropathy (CIE) and different serum concentrations of cobalamin.

Objective

To compare endoscopic and histologic ileal findings in dogs with CIE and different serum cobalamin concentrations and then evaluate the correlation of ileal changes to cobalamin serum concentration using updated scoring systems to assess the ileum.

Animals

Sixty‐eight dogs with CIE.

Methods

Retrospective study. Frequency of ileal features and ileal histologic and endoscopic scores (IHS and IES) were obtained and compared among CIE dogs with severe hypocobalaminemia (SHC; <200 ng/L), hypocobalaminemia (HC; 200‐350 ng/L), or normocobalaminemia (NC; >350 ng/L). The correlation of IHS and IES with cobalamin was evaluated.

Results

Friability, villus atrophy, crypt dilatation, epithelial injury, and intraepithelial lymphocytes were more frequent in SHC than in NC dogs (all P ≤ .01). Median SHC‐IES (2; range, 0‐4) was higher than NC‐IES (1; range, 0‐5; P = .004). Median SHC‐IHS (6; range, 3‐9) was higher than HC‐IHS (4; range, 1‐7; P < .001) and NC‐IHS (3; range, 1‐8; P < .001). Cobalamin concentration correlated negatively with IES (ρ = −.34, P = .005) and IHS (ρ = −.58, P < .001).

Conclusions and Clinical Importance

Ileal features and involvement degree markedly differed when cobalamin was <200 or >350 ng/L in CIE dogs. With updated scales to assess the mucosa, greater ileal damage was associated with lower serum cobalamin concentration.

Evaluation of the degree and distribution of lymphangiectasia in full-thickness canine small intestinal specimens diagnosed with lymphoplasmacytic enteritis and granulomatous lymphangitis

Intestinal lymphangiectasia (IL) is often observed in dogs with chronic small intestinal diseases. Hypoplasia of the lymphatic vessel due to decreased lymphangiogenesis, which has been suggested in human idiopathic IL, may contribute to the pathogenesis of canine IL. This study aimed to evaluate the diameter and number of lymphatic vessels in full-thickness small intestinal specimens of dogs with IL. Immunohistochemical labeling of lymphatic endothelial cell markers was performed on retrospectively retrieved full-thickness small intestinal specimens. Sixteen dogs with histologically confirmed IL were included, of which 10 had lymphoplasmacytic enteritis (LPE), and six had granulomatous lymphangitis (GL). Nine dogs that died from non-gastrointestinal disorders and with little or no abnormalities in the small intestine were used as controls. Lymphatic vessel diameters in dogs with IL were significantly increased in all layers of the small intestine, including the villus lacteal, lamina propria, submucosa, muscularis, and mesentery, compared with controls (all P<0.01). There was no significant difference in the lymphatic vessel diameters between dogs with LPE and GL (all P>0.05). There was no significant difference in the number of lymphatic vessels between dogs with IL and the controls in all layers of the small intestine (all P>0.05). This study demonstrated that IL was observed in all layers of the small intestine, including the submucosa, muscularis, and mesentery, independent of the underlying disease. Factors other than reduced lymphatic vessels would contribute to the pathogenesis of IL in dogs.

Association between intestinal lymphangiectasia and expression of inducible nitric oxide synthase in dogs with lymphoplasmacytic enteritis

Intestinal lymphangiectasia (IL) is a common complication in dogs. Since nitric oxide (NO) is known to relax the lymphatic vessel, we evaluated inducible NO synthase (iNOS) expression using immunohistochemistry in 13 dogs with lymphoplasmacytic enteritis (LPE) with or without IL. The duodenal iNOS expressing cells were significantly increased in dogs with IL-negative or IL-positive LPE dogs (P=0.025, P=0.007) compared with control dogs. However, there was no significant difference in iNOS expression between IL-positive and IL-negative tissues. Based on these results, there is no clear evidence for the NO overproduction in the pathogenesis of IL in dogs with LPE. Factors other than NO could, thus, contribute to IL in dogs with LPE.

Latanoprost eye drops induce conjunctival lymphatic vessel development

AIM

To investigate the effect of latanoprost eye drops on the conjunctival lymphatics.

METHODS

Twenty-four healthy New Zealand White rabbits weighing 1.5 to 2.0 kg were randomly divided into three groups: latanoprost group (n=8) administered with latanoprost eye drops once a day for 2mo, carteolol group (n=8) administered with carteolol eye drops once a day for 2mo, and control group (n=8) without any treatment. The conjunctival tissues in the three groups were extracted to investigate the expression levels of 5'-nucleotidase (5'-Nase) by Western blot, reverse transcription-polymerase chain reaction (RT-PCR), and immunofluorescence staining, respectively.

RESULTS

The protein expression level of 5'-Nase was significantly higher in latanoprost group than carteolol group (F=231.175, P<0.001) and control group (P<0.001), while there was no significant difference between the carteolol group and the control group (P>0.05). The mRNA expression level of 5'-Nase in the latanoprost group was also significantly higher than carteolol group (F=71.169 P<0.005) and control group (P<0.005). The conjunctival lymphatics were positive immunofluorescence stained with the 5'-Nase antibodies in the latanoprost group and not stained in the control group.

CONCLUSION

Latanoprost eye drops can induce conjunctival lymphangiogenesis which may be concerned in clinical implications.

International Guidelines for Veterinary Tumor Pathology: A Call to Action

Standardization of tumor assessment lays the foundation for validation of grading systems, permits reproducibility of oncologic studies among investigators, and increases confidence in the significance of study results. Currently, there is minimal methodological standardization for assessing tumors in veterinary medicine, with few attempts to validate published protocols and grading schemes. The current article attempts to address these shortcomings by providing standard guidelines for tumor assessment parameters and protocols for evaluating specific tumor types. More detailed information is available in the Supplemental Files, the intention of which is 2-fold: publication as part of this commentary, but more importantly, these will be available as "living documents" on a website (www.vetcancerprotocols.org), which will be updated as new information is presented in the peer-reviewed literature. Our hope is that veterinary pathologists will agree that this initiative is needed, and will contribute to and utilize this information for routine diagnostic work and oncologic studies. Journal editors and reviewers can utilize checklists to ensure publications include sufficient detail and standardized methods of tumor assessment. To maintain the relevance of the guidelines and protocols, it is critical that the information is periodically updated and revised as new studies are published and validated with the intent of providing a repository of this information. Our hope is that this initiative (a continuation of efforts published in this journal in 2011) will facilitate collaboration and reproducibility between pathologists and institutions, increase case numbers, and strengthen clinical research findings, thus ensuring continued progress in veterinary oncologic pathology and improving patient care.

Prospective evaluation of a change in dietary therapy in dogs with steroid-resistant protein-losing enteropathy

OBJECTIVE

To describe the clinical effect of dietary alteration as a sole change to therapy in dogs with steroid-resistant protein-losing enteropathy.

MATERIALS AND METHODS

Prospective study. Eligible enrolled dogs received dietary alteration as sole change to their therapeutic plan. Canine Chronic Enteropathy Clinical Activity Index and serum albumin were monitored for the 3-month study period. Long-term follow-up data were also available for some of the study participants.

RESULTS

Fifteen dogs were eligible for enrollment over the study period. Twelve were enrolled, 10 remained in the study at 30 days, nine completed the 3-month study period. Following dietary alteration, eight of 10 dogs achieved complete remission, one dog achieved partial remission and one dog had no response. Seven of eight dogs achieving complete remission have remained in remission up to 4 years following study. In dogs with complete remission, median Canine Chronic Enteropathy Clinical Activity Index score was 11.5 and 4, and median serum albumin concentration was 15 g/L and 26 g/L at 0 and 14-28 days, respectively.

CLINICAL SIGNIFICANCE

Dogs with protein-losing enteropathy with previous lack of response to a combination of dietary therapies, glucocorticoids and immunosuppressive medications can achieve remission following a dietary change. Improvement is likely to be seen within 14 to 30 days. A change in dietary approach may be an alternative to further immunosuppression or anti-inflammatory strategies in some dogs with difficult to treat protein-losing enteropathy.

Canine Protein Losing Enteropathies and Systemic Complications

Canine protein-losing enteropathies occur commonly in small animal practice, and their management is often challenging with a long-term survival rate of only about 50%. Recent studies have investigated prognostic factors that may determine outcome in individual cases. In particular, systemic complications such as hypercoagulability, vitamin D3 deficiency, and tryptophan deficiency may play an important role and should be investigated in severely affected cases in order to maximize outcome.

Lymphatic endothelial cell immunohistochemical markers for evaluation of the intestinal lymphatic vasculature in dogs with chronic inflammatory enteropathy

Background

Lymphatic endothelial cell (LEC) immunohistochemical markers have identified intestinal lymphatic vasculature abnormalities in humans with inflammatory bowel disease, but have not been used to evaluate intestinal lymphatic vasculature in a group of dogs with chronic inflammatory enteropathy (CIE).

Objectives

To utilize LEC markers to identify and measure intestinal lymphatic vasculature in endoscopic biopsy samples of CIE dogs. To evaluate whether measured lymphatic vasculature variables correlate with serum albumin concentrations.

Animals

Twenty‐four dogs with CIE; n = 13, serum albumin concentration <2.5 g/dL (CIE‐protein‐losing enteropathy [PLE]), n = 11, serum albumin concentration ≥2.5 g/dL (CIE‐N).

Methods

Prospective study. Lymphatic endothelial cell immunolabeling with Prox‐1 and LYVE‐1 performed on endoscopic biopsy samples from 24 dogs with CIE. Duodenal and ileal villous lacteal width (VLW) and proprial mucosal lacteal width (MLW) were determined for each case and analyzed for correlation with serum albumin concentration. Lacteal dilatation scores using routine H&E histopathology were assessed for correlation with immunohistochemistry (IHC)‐calculated VLW and MLW.

Results

Lower serum albumin concentrations were correlated with increased VLW (rho = −.4644; P = .02) and MLW (rho = −.6514; P < .001) in the ileum. Lymphatic endothelial cell IHC identified presumptive proprial mucosal lymphangiectasia in some dogs that was not recognized with routine H&E staining. Lacteal dilatation scores were correlated with VLW in duodenum (rho = .4634; P = .02) and ileum (rho = .5292; P = .008), but did not correlate with MLW.

Conclusions and Clinical Importance

Lymphatic endothelial cell immunolabeling identified presumptive proprial mucosal lymphangiectasia in CIE dogs, particularly in the ileum of hypoalbuminemic dogs. Routine evaluation of villous lacteals likely underestimates abnormalities of the lymphatic vasculature in dogs with CIE.