Hepatic lead and copper concentrations in dogs with chronic hepatitis and their relationship with hematology, serum biochemistry, and histopathology

Mortality and heavy metals environmental exposure: a study in dogs

Introduction

Dogs are human companions and share environmental conditions with their owners. Epidemiological studies have shown that dogs seem to be good sentinel animals for the association of diseases and/or mortality provoked by chronic exposure to heavy metals (Cd, Pb).

Methods

In the present work, we analyze the registered death cases and population from the National Canine Registry from 2020 to 2022, involving a dog population of 582,564 and 17,507 deaths. The mortality rate in male and not-purebred dogs is higher than in female and purebred dogs, respectively. The mortality cases were cross-referenced with the environmental pollution data relating to the concentration of Cd and Pb detected, between 2012 and 2022, in the various municipalities of the Liguria region. We then calculated SMR (Standardized Mortality Rate) throughout the region and found that mortality increases from the eastern to the western Ligurian coast.

Results and discussion

We observed that the most polluted areas present the highest SMRs (IRR = 1.36, 95%CI: from 1.31 to 1.41). Considering dog ages, we found that mortality in young dogs is not affected by pollution, while mortality in old dogs (10-20 years old) is heavily affected by it (IRR = 8.97, 95%CI from 8.09 to 9.93). In conclusion, the data suggest the importance of canine health and biomonitor studies and provide a basis for future research involving both animal and human health.

Copper metabolism and its implications for canine nutrition

Canine copper nutrition has received increased attention due to recent reports of apparent copper-associated hepatitis in the USA and European Union. In order to properly address the need to modify the U.S. National Research Council and Association of American Feed Control Officials canine copper recommendations that will have implications for all dogs, it is important to understand the complexities of copper metabolism, confounding variables affecting copper status, and the available research on this topic in dogs. Recent trends in consumer preference for dog diets, supplements, and functional treats introduce another layer of complexity, as most ingredients used in these formulations provide vastly different proportions of essential nutrients, thus resulting in great variation in nutrient profiles available to the animal. Although controlled research addressing copper metabolism in dogs is limited, there are lessons to be learned from other monogastric species as well as canine case studies that can provide a base for increasing knowledge to address this issue. Copper metabolism and status in animals is affected by a multitude of factors including absorption, storage, excretion, and nutrient interactions. Given its vital role in many physiological processes, it is important that both nutritional deficiencies and toxicities be avoided. Additionally, another challenge for proper copper nutrition in dogs is the known genetic predispositions of some breeds for copper storage and excretion abnormalities. Therefore, it is imperative that veterinarians, nutritionists, and pet food manufacturers collaborate with the shared goal of providing dog food options that supply the essential nutrients at adequate concentrations to support an active and healthy life. Many questions remain regarding copper metabolism and proper diet formulation for dogs. Future research efforts should focus on discovering reliable, non-invasive methods for evaluating canine copper status, a deeper understanding of genetic predispositions of certain breeds, increased knowledge of copper contributions from various ingredients, and the role of unpredictable physiological stressors on copper metabolism.

Characterization of clinical presentation, histological features, ultrasonographic findings, and survival in 29 dogs with granulomatous hepatitis

BACKGROUND

Granulomatous hepatitis (GH) is a form of chronic hepatitis (CH) in dogs for which limited information is published.

HYPOTHESIS

Describe the clinical presentation, clinical pathology, ultrasound, and hepatic histopathology findings and to report survival times in dogs with GH.

ANIMALS

Twenty-nine client-owned dogs with GH.

METHODS

Retrospective observational study. Pathology records were searched. Inclusion criteria included a histopathologic diagnosis of GH, absence of an identified etiology or evidence of extrahepatic granulomatous disease, and a medical record available for review. Clinical presentation, clinical pathologic findings, treatment protocols, and survival times were recorded. Available hepatic biopsy material was graded and scored, and ultrasound evaluations reviewed.

RESULTS

The median age was 7 years (range, 0.66-12 years). Nineteen breeds were represented. Decreased appetite (19/29), lethargy (16/29), and fever (13/29) were seen most commonly. All dogs had increased serum transaminase activities, whereas 21/29 and 12/24 had hyperbilirubinemia and neutrophilia, respectively. Ultrasonographic findings included hepatomegaly (12/22), nodular parenchymal lesions (9/22), and hyperechoic parenchymal bands (8/22). Histopathologic necroinflammatory scores were moderate to severe in 16/19 dogs, and fibrosis scores were mild in 14/19 dogs. Treatments varied and included antibiotics, immunosuppressive drugs, and hepatoprotectants. Overall median survival was 635 days (range, 1-2482 days).

CONCLUSION AND CLINICAL IMPORTANCE

Granulomatous hepatitis in dogs is associated with high histopathologic grade, fever, neutrophilia, and a high incidence of hepatomegaly and focal parenchymal lesions on ultrasound examination. Despite disease severity on presentation, dogs with GH can have a good outcome with prolonged survival.

Source apportionment based on lead isotope ratios: Could domestic dog's blood lead be used to identify the level and sources of lead pollution in children?

Domestic dogs have been proved to be used as "sentinel organisms" to monitor human lead exposure. However, whether dogs' blood can be used to identify the levels and pollution source of children's lead exposure still needs evidence. To evaluate the potential use of domestic dogs' blood lead as an indicator of lead exposure levels and pollution source of children, accompanying with potential environmental media samples, lead concentrations and isotope ratios (expressed as ²⁰⁷Pb/²⁰⁶Pb, ²⁰⁸Pb/²⁰⁶Pb) in blood were investigated and compared between children and dogs, who came from a Pb-Zn smelter area, a coal fired area and a control area without industrial activity. The results showed that there were significant correlations in blood lead levels (BLLs) between children and dogs in the study areas (p < 0.01). The lead isotope ratios (LIRs) in blood of children and dogs were disparate among the three areas, however, the LIRs of dogs were quite correlated with those of children in each area (p < 0.01). With the comparison of LIRs between potential pollution sources (slag, ore, coal, paint) and blood samples, the identified lead sources based on dogs' blood were found to be coincident with those based on children's blood. Ore smelting and coal combustion were the main sources of lead exposure for the dogs and children in the smelting area, and coal combustion was the predominant source for the children and dogs living in the coal burning area and control area. The results showed that dogs' BLLs might be used to estimate children's BLLs, and blood LIRs measurements of dogs' could be used as an alternative for identifying the sources of children's lead exposure. This study further provided relevant evidence for dogs to be sentinels exposed to human lead exposure and an alternative method for source apportionment of children's lead exposure.

Serum Amino Acids Imbalance in Canine Chronic Hepatitis: Results in 16 Dogs

Simple Summary

Human chronic liver disease is reported to be associated with alterations in amino acids metabolism, with a decrease in serum branched-chain amino acids and an increase in aromatic amino acids. A decreased Fischer ratio (branched to aromatic amino acids ratio) has showed prognostic significance and is a therapeutic target in human cirrhosis. In dogs, few studies have been performed, and the Fischer ratio seems to be reduced in animals with congenital portosystemic shunts. The aim of this study was to evaluate serum amino acids in dogs with chronic hepatic inflammation compared with healthy dogs. The serum amino acids in dogs with chronic hepatitis were also evaluated in relation to their histological severity. Eighteen amino acidic metabolites were measured using the leftover serum samples of 16 dogs with histological chronic hepatitis and 25 healthy dogs. Several amino acid concentrations were significantly different between dogs diagnosed with chronic hepatitis and healthy controls. In human medicine, aromatic amino acids seem to increase during chronic hepatitis, whereas isoleucine decreases. The Fischer ratio was significantly reduced if higher grades of fibrosis were present. Even if total serum proteins did not significantly differ between groups, we observed qualitative imbalances in serum amino acids among dogs presenting with chronic hepatitis.

Abstract

In humans, chronic liver disease may cause alterations in amino acids (AAs) metabolism, with serum branched-chain AAs (BCAAs) decreasing and aromatic AAs (AAAs) increasing. A reduced Fischer ratio (BCAAs/AAAs) has been found to be associated with hepatic fibrosis and is useful for assessing prognosis in human patients. In veterinary medicine, few studies have been performed, and in contrast to human patients, dogs with different kinds of hepatopathy tend to show both increased AAAs and BCAAs. In dogs, the association between histological scores and serum AAs has not been previously investigated. The aim of this study was to evaluate serum AAs in dogs with chronic hepatitis (CH) compared with a healthy control group (C) and, among CH dogs, in relation to their histological fibrosis and necroinflammatory activity scores. Leftover serum samples of 16 dogs with histological CH and 25 healthy dogs were employed. Serum AAs were measured by high performance liquid chromatography. Proline and the AAAs phenylalaine and tyrosine progressively increased with the histological severity. In contrast, cysteine, tryptophan and BCAA isoleucine progressively reduced. Lysine and the BCAAs leucine and valine showed a non-linear trend with the histological findings. The BCAAs/AAAs ratio was significatively reduced if higher grades of liver fibrosis were present.

Serum protein electrophoresis in 26 dogs with chronic hepatitis

Serum protein electrophoresis (SPE) shows the distribution of protein fractions, helping clinicians to characterize some pathologic processes. Information is lacking in the literature about SPE alterations in dogs with chronic hepatitis (CH). Our aim was to describe SPE alterations in canine CH, to compare SPE results to histologic scores, and to study SPE trends during follow-up. We reviewed retrospectively case data from dogs with a histologic diagnosis of CH. Only cases with SPE, CBC, and serum chemistry results available were included. Dogs were divided into subgroups based on histologic necroinflammatory activity (A) and fibrosis (F) scores (groups A0-1 and A>1; groups F<2 and F≥2). We included 26 dogs; 15 had follow-up SPE. The most common SPE alterations at admission were hypoalbuminemia (n = 16), increases in α1-globulins (n = 11), γ-globulins (n = 11), α2-globulins (n = 8), β2-globulins (n = 7), and β1-globulins (n = 6), and decreased albumin:globulin (A:G) ratios (n = 20). Four of 11 dogs had β-γ bridging. Groups with higher A and F scores had higher β2-globulins. Eleven of 15 dogs with a post-treatment SPE had a decrease in γ-globulins and increase in A:G ratio compared to their T0, although there was no statistically significant difference. Although further studies are warranted, SPE may be useful for monitoring canine CH.

Hepatic lead and copper concentrations in dogs with chronic hepatitis and their relationship with hematology, serum biochemistry, and histopathology

BACKGROUND

Although the influence of copper ([Cu]) on chronic hepatitis (CH) has been widely studied in dogs, little information is available about the accumulation of other metals.

HYPOTHESIS/OBJECTIVES

We assessed the concentration of lead ([Pb]) in the livers of dogs with CH with or without abnormal hepatic [Cu] to establish if any association existed between [Pb] and either hematologic or biochemical variables, fibrosis, necrosis and inflammation of the liver on histology.

ANIMALS

Thirty-four dogs with CH that had hepatic [Cu] and [Pb] determined.

METHODS

Retrospective review of medical records of dogs with CH and hepatic [Cu] and [Pb]. Chronic hepatitis was defined using current American College of Veterinary Internal Medicine consensus statement guidelines. Hepatic [Cu] and [Pb] were determined using square wave anodic stripping voltammetry. Dogs were divided into 2 groups based on [Cu]: <400 ppm (LoCu) and ≥400 ppm (HiCu).

RESULTS

The median [Cu] and [Pb] were 357 ppm (range, 100-7743 ppm) and 58.7 (range, 6.89-224.4 ppm), respectively. Nineteen dogs had LoCu and 15 dogs had HiCu. Median [Pb] was significantly higher in HiCu compared to LoCu dogs (P < .001). Hepatic [Pb] and [Cu] were significantly correlated (rho = 0.7; P < .001). Dogs with microcytosis had higher [Pb] than did dogs with normal red cell volume (P = .02). Hepatic [Pb] was not correlated with either necroinflammatory or fibrosis scores.

CONCLUSIONS AND CLINICAL IMPORTANCE

Although additional studies are needed to better understand the clinical role of hepatic [Pb], dogs with abnormal hepatic [Cu] may also have higher hepatic [Pb]. In addition, in dogs with high hepatic [Pb], microcytosis may be present.