Blood vitamin levels in dogs with chronic kidney disease

Dysregulated serum concentrations of fat-soluble vitamins in dogs with chronic enteropathy

BACKGROUND

In inflammatory bowel disease (IBD) of humans, nutrient malabsorption can result in fat-soluble vitamin deficiency, especially of vitamin D. In veterinary species, decreased concentrations of vitamin D are relatively common in dogs with chronic enteropathy (CE), but data on the status of other fat-soluble vitamins (FSVs) is lacking.

OBJECTIVES

Determine the serum concentrations of retinol, vitamin D, and α-tocopherol in dogs with CE compared with healthy dogs and compare clinical, clinicopathologic variables between CE and healthy dogs to detect associations with decreased FSVs concentrations.

ANIMALS

Eighteen client-owned dogs with CE and 33 healthy dogs.

METHODS

Serum 25-hydroxyvitamin D (25[OH]D), serum retinol and α-tocopherol concentrations were compared between groups. Correlations and multiple regression modeling were used to examine the relationship between serum 25(OH)D, retinol, and α-tocopherol concentrations and clinical and clinicopathological variables.

RESULTS

Dogs with low serum albumin concentrations were more likely to have lower 25(OH)D concentrations than dogs with normal serum albumin concentration. Dogs with CE had higher serum concentrations of retinol, and variable α-tocopherol concentrations. The cause of these dysregulated vitamin concentrations is unclear and requires further study.

CONCLUSION AND CLINICAL IMPORTANCE

Dogs with severe forms of CE should be monitored for decreased concentrations of 25(OH)D. Additional studies are needed to evaluate the clinical relevance and the possible benefit of vitamin D supplementation in these patients.

The therapeutic effect of wine-processed Corni Fructus on chronic renal failure in rats through the interference with the LPS/IL-1-mediated inhibition of RXR function

ETHNOPHARMACOLOGICAL RELEVANCE

Corni Fructus, derived from the fruit of Cornus officinalis Sieb. et Zucc, is a widely utilized traditional Chinese medicine (TCM) with established efficacy in the treatment of diverse chronic kidney diseases. Crude Corni Fructus (CCF) and wine-processed Corni Fructus (WCF) are the main processed forms of Corni Fructus. Generally, TCM is often used after processing (paozhi). Despite the extensive use of processed TCM, the underlying mechanisms of processing for most TCMs have been unclear so far.

AIM OF THE STUDY

In this study, an integrated strategy combined renal metabolomics with proteomics was established and investigated the potential processing mechanisms of CCF or WCF on chronic renal failure (CRF) models.

MATERIALS AND METHODS

Firstly, the differences in biochemical parameters and pathological histology were compared to evaluate the effects of CCF and WCF on CRF model rats. Then, the tissue differential metabolites and proteins between CCF and WCF on CRF model rats were screened based on metabolomics and proteomics technology. Concurrently, a combined approach of metabolomics and proteomics was employed to investigate the underlying mechanisms associated with these marker metabolic products and proteins.

RESULTS

Compared to the MG group, there were 27 distinct metabolites and 143 different proteins observed in the CCF-treatment group, while the WCF-treatment group exhibited 24 distinct metabolites and 379 different proteins. Further, the integration interactions analysis of the protein and lipid metabolite revealed that both WCF and CCF improved tryptophan degradation and LPS/IL-1-mediated inhibition of RXR function. WCF inhibited RXR function more than CCF via the modulation of LPS/IL-1 in the CRF model. Experimental results were validated by qRT-PCR and western blotting. Notably, the gene expression amount and protein levels of FMO3 and CYP2E1 among 8 genes influenced by WCF were higher compared to CCF.

CONCLUSION

The results of this study provide a theoretical basis for further study of Corni Fructus with different processing techniques in CRF. The findings also offer guidance for investigating the mechanism of action of herbal medicines in diseases employing diverse processing techniques.

The effects of age, sex, breed, diet, reproductive status and housing condition on the amounts of 25(OH) vitamin D in the serum of healthy dogs: Reference values

BACKGROUND

Optimal amount of vitamin D for the proper functioning of the immune system is different from the required vitamin D amount for bones to prevent rickets. However, reports on vitamin D reference values in dogs are minimal, and there is still not enough information regarding the relationship between vitamin D and various variables such as disease, age, breed, diet type, and so on, as well as its relationship with haematological and serum biochemical parameters.

OBGECTIVES

The present study aimed to determine reference values of 25(OH) Vit D in dogs and its concentration in different groups, categorized based on age, sex, breed, housing conditions, and diet, as well as 25(OH) Vit D relationship with hematology and serum biochemistry parameters.

METHODS

In this study, 90 healthy dogs were selected to determine the reference value of 25 (OH) Vit D of serum after evaluating of their haematological and biochemical parameters to assess their general health. Dogs were divided into different groups according to above-mentioned variables. Serum 25 (OH) Vit D was subsequently measured by the ELISA method.

RESULTS

The median concentration of 25 (OH) Vit D was 52.50 ng/ml with minimum and maximum amounts of 14.00 and 155.57 ng/ml, respectively. No significant difference was observed between 25 (OH) Vit D levels in the studied dogs regarding their different age, sex, breed, diet, housing condition, and reproductive status. Serum 25 (OH) Vit D concentration is directly correlated with the number of band neutrophils (p < 0.05). We also witnessed indirect correlations between serum 25 (OH) Vit D levels and the number of blood eosinophils and serum glucose (p < 0.05).

CONCLUSION

In the present study age, sex, breed, housing condition and age had no significant effects on the amounts of 25(OH) vitamin D. According to correlations of vitamin D with MCH, band and eosinophil numbers and glucose, vitamin D may have a role in erythropoiesis and leukocytes response and also in energy metabolism in dog.

Evaluation of blood thiamine concentration in hospitalized dogs with and without critical illness

OBJECTIVE

To evaluate blood thiamine concentration in healthy and critically ill hospitalized dogs over 72 hours of hospitalization and to identify any association of thiamine concentration with patient morbidity and mortality.

DESIGN

Prospective, observational, clinical study.

SETTING

University veterinary teaching hospital.

ANIMALS

Thirty-one hospitalized healthy dogs and 37 dogs with critical illness. Dogs with critical illness had nonseptic (n = 24) or septic (n = 13) etiologies.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Whole blood EDTA samples were collected within 24 hours of admission and 72 hours later. Samples were stored at -80°C and batch analyzed. Total thiamine (tB1) and thiamine diphosphate (TDP) concentrations were measured using high-performance liquid chromatography, and free thiamine concentration was determined using liquid chromatography with tandem mass spectrometry. Collected patient data included CBC, biochemistry profile, plasma lactate concentration, shock index, Acute Patient Physiologic and Laboratory Evaluation Score (APPLE_fast ) score, comorbid conditions, and patient outcome. Approximately 92% of tB1 present in whole blood is measured as TDP. TDP concentration was strongly correlated with tB1 (R = 0.97, P < 0.0001). Thiamine concentration, represented by TDP, was not different at admission or at 72 hours in all dogs. TDP concentration was lower in septic dogs requiring surgery at admission (P = 0.044) and 72 hours later (P = 0.008), compared to dogs not requiring surgery. TDP concentration was not different between dogs with and without stable chronic diseases at any time point. Older dogs had lower TDP concentration. Positive correlations were seen between TDP and body weight, APPLE_fast score, and WBC count. Critically ill dogs with lower admission plasma lactate concentration were more likely to have an increase in thiamine over time (P = 0.0142).

CONCLUSIONS

Differences in thiamine concentration were not identified in hospitalized healthy or critically ill dogs. Further investigation into the clinical relevance of thiamine deficiency is indicated in septic dogs undergoing surgery.

Persistent hypercobalaminemia three months after successful gradual attenuation of extrahepatic shunts in dogs: a prospective cohort study

Background

Deficiencies in vitamin A and D and disorders in the vitamin B complex are often present in people with chronic liver diseases. So far, the serum concentrations of these vitamins have not yet been studied in dogs with congenital extrahepatic portosystemic shunts (EHPSS), who also have some degree of liver dysfunction. The objective was to assess serum vitamin concentrations in dogs with EHPSS from diagnosis to complete closure. A prospective cohort study was performed using ten client-owned dogs with EHPSS, closed after gradual surgical attenuation. Serum concentrations of vitamin A, 25-hydroxyvitamin D, folic acid, cobalamin and methylmalonic acid (MMA) were measured at diagnosis prior to institution of medical therapy, prior to surgery, and three months after gradual attenuation and complete closure of the EHPSS.

Results

At diagnosis, median serum concentrations of vitamin A, 25-hydroxyvitamin D and folic acid were 18.2 μg/dL (8.8 - 79.5 μg/dL), 51.8 ng/mL (19.4 - 109.0 ng/mL), and 8.1 μg/L (5.2 - 14.5 μg/L), respectively, which increased significantly postoperatively (88.3 μg/dL (51.6 - 182.2 μg/dL, P=0.005), 89.6 ng/mL (49.3 - >150.0 ng/mL, P =0.005), and 14.8 μg/L (11.5 - 17.7 μg/L, P <0.001), respectively). Median serum cobalamin concentrations were 735.5 ng/L (470 - 1388 ng/L) at diagnosis and did not significantly decrease postoperatively (P =0.122). Both at diagnosis and three months postoperatively 7/10 dogs had hypercobalaminemia.

Conclusions

Serum concentrations of vitamin A, 25-hydroxyvitamin D and folic acid significantly increase after surgical attenuation. Nevertheless, persistent hypercobalaminemia is suggestive of ongoing liver dysfunction, despite successful surgery.

Vitamin D metabolism and disorders in dogs and cats

Vitamin D plays an important role in regulating calcium metabolism and in the development and maintenance of skeletal health of companion animals. There is also a growing interest in understanding the role vitamin D plays in non-skeletal health in both human and veterinary patients. This review provides an update of our current understanding of vitamin D biology in dogs and cats and gives an overview of how vitamin D metabolism can be assessed in companion animals. Congenital and acquired vitamin D disorders are then summarised before the review concludes with a summary of recent studies which have explored the role of vitamin D in the development and outcomes of non-skeletal diseases of dogs and cats.

Serum cobalamin concentrations in dogs with leishmaniosis before and during treatment

Hypocobalaminemia in dogs is most commonly associated with gastrointestinal disorders leading to impaired absorption and utilization of cobalamin. The objectives of this study were to compare serum cobalamin concentrations between dogs with leishmaniosis and clinically healthy dogs, and to assess possible alterations of serum cobalamin concentrations in dogs with leishmaniosis at different timepoints during treatment. Fifty-five dogs with leishmaniosis and 129 clinically healthy dogs were prospectively enrolled. Diagnosis of leishmaniosis was based on clinical presentation, positive serology and microscopic detection of Leishmania amastigotes in lymph node aspiration smears. Twenty of the dogs with leishmaniosis were treated with a combination of meglumine antimonate and allopurinol for 28 days and serum cobalamin concentrations were measured in blood samples that were collected before initiation of treatment (timepoint 0) and on days 14 and 28. In order to estimate alterations of serum cobalamin concentrations during treatment, cobalamin concentrations were measured in blood samples from 20 out of 55 dogs with leishmaniosis at all timepoints. Serum cobalamin concentrations were significantly lower in dogs with leishmaniosis before treatment (median: 362 ng/L; IQR: 277-477 ng/L) compared to clinically healthy dogs (median: 470 ng/L; IQR: 367-632 ng/L; P = 0.0035). Serum cobalamin concentrations increased significantly in dogs with leishmaniosis on day 14 of treatment compared to timepoint 0 (P = 0.02). In the present study, serum cobalamin concentrations were significantly lower in dogs with leishmaniosis compared to clinically healthy dogs. In addition, there was an increase in serum cobalamin concentrations during treatment. The clinical significance of hypocobalaminemia in dogs with leishmaniosis remains to be determined.

Plasma 25-hydroxyvitamin D and the inflammatory response in canine cancer

Decreased circulating 25-hydroxyvitamin D (25[OH]D) and increased inflammatory marker concentrations have been reported separately in canine cancer. Correlations between the two exist in humans, but little work has examined links in dogs. This study aimed to determine plasma 25(OH)D and inflammatory marker concentrations in healthy dogs and dogs with cancer and to assess correlations in each group. Newly diagnosed dogs with B-cell lymphoma (B-cell, n = 25), T-cell lymphoma (T-cell, n = 9), osteosarcoma (OSA, n = 21), and mast cell tumour (MCT, n = 26) presenting to a tertiary oncology centre, and healthy dogs (n = 25), were enrolled. Plasma samples were analysed for 25(OH)D, C-reactive protein (CRP), haptoglobin (HP), serum amyloid A (SAA), alpha-1-acid glycoprotein (AAG), and 13 chemokines and cytokines. Dogs with B-cell had decreased plasma 25(OH)D (P = .03), and increased plasma CRP, AAG, HP, KC-like and MCP-1 concentrations (P < =.001, .011, <.001, .013 and .009, respectively) compared with healthy dogs. Plasma CRP, HP and SAA concentrations were increased in dogs with OSA compared with healthy dogs (P = .001, .010 and .027, respectively). No differences were noted in dogs with T-cell and MCT. Negative correlations were observed between plasma 25(OH)D concentrations and: AAG concentrations in dogs with T-cell (R_s  = -0.817, P = .007); GM-CSF concentrations (R_s  = -0.569, P = .007) in dogs with OSA; and IL-7 concentrations (R_s  = -0.548, P = .010) in dogs with OSA. Decreased 25(OH)D concentrations and increased concentrations of multiple inflammatory markers were observed in B-cell patients, supporting an association between 25(OH)D and inflammation. The cross-sectional study design meant the timing of changes could not be determined. Prospective cohort studies are warranted.

The Role of Vitamin D in Small Animal Bone Metabolism

Dogs and cats have differences in vitamin D metabolism compared to other mammalian species, as they are unable to perform vitamin D cutaneous synthesis through sun exposure. Therefore, they are dependent on the dietary intake of this nutrient. The classic functions of vitamin D are to stimulate intestinal calcium and phosphate absorption, renal calcium and phosphate reabsorption and regulate bone mineral metabolism. Thus, it is an important nutrient for calcium and phosphorus homeostasis. This review highlights the evidence of the direct and indirect actions of vitamin D on bone mineral metabolism, the consequences of nutritional imbalances of this nutrient in small animals, as well as differences in vitamin D metabolism between different size dogs.

Association between vitamin D metabolites, vitamin D binding protein, and proteinuria in dogs

BACKGROUND

Proteinuria has been associated with progression of renal disease and increased morbidity and mortality in dogs and people. In people, proteinuria also has been associated with hypovitaminosis D. Little is known about the relationship between vitamin D metabolism and proteinuria in dogs.

OBJECTIVES

To further elucidate vitamin D status in dogs with protein-losing nephropathy (PLN) and minimal to no azotemia. We hypothesized that vitamin D metabolites would be lower in dogs with PLN compared to healthy dogs.

ANIMALS

Twenty-three client-owned adult dogs with PLN and 10 healthy control dogs.

METHODS

Serum 25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D (1,25[OH]₂ D), 24,25-dihydroxyvitamin D (24,25[OH]₂ D), serum vitamin D binding protein (VDBP), and urine 25(OH)D concentrations were measured.

RESULTS

Compared to healthy dogs, dogs with PLN had lower concentrations of all vitamin D metabolites (P < .01). Correlations (rho; 95% confidence interval [CI]) in dogs with PLN are reported. Serum 25(OH)D and 24,25(OH)₂ D concentrations were positively correlated with albumin (r = 0.47; 0.07-0.74), and 24,25(OH)₂ D was negatively correlated with urine protein-to-creatinine ratio (UPC; r = -0.54; -0.78 to -0.16). Urine 25(OH)D-to-creatinine ratio was negatively correlated with serum albumin concentration (r = -0.77; -0.91 to -0.50) and positively correlated with UPC (r = 0.79; 0.53-0.91). Serum VDBP concentration was positively correlated with serum albumin concentration (r = 0.53; 0.05-0.81).

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs with PLN have decreased serum concentrations of vitamin D metabolites. Urine 25(OH)D-to-creatinine ratio and UPC are correlated in PLN dogs. Future studies are needed to assess additional management strategies for dogs with PLN.

CHANGES IN ANTIOXIDANT CAPACITY OF KOALAS (PHASCOLARCTOS CINEREUS) BASED ON HEALTH STATUS AND MEASUREMENT OF THE ANTIOXIDANT ASCORBATE IN EUCALYPT LEAVES

Antioxidants have a crucial role in protecting the body from oxidative stress, which would otherwise result in cellular damage and possibly predispose animals to disease. The antioxidant capacity of koalas (Phascolarctos cinereus) and its association with health or disease status is currently unknown. Ascorbate, a dietary antioxidant, has previously been identified in a few eucalypt species eaten by koalas. This study aimed to determine 1) differences between the antioxidant capacity of healthy and diseased koalas, and 2) concentration of the antioxidant ascorbate in Eucalyptus spp. leaves eaten by koalas. To determine differences in antioxidant capacity of koalas, plasma samples from clinically healthy koalas in Kangaroo Island, South Australia (SA) (n = 23), euthanized koalas with oxalate nephrosis from Mount Lofty Ranges, SA (n = 11), and euthanized koalas with chlamydiosis from Moggill, Queensland (n = 11) were analyzed for the three antioxidants α-tocopherol, ascorbate, and retinol and for two measures of antioxidant capacity, ferric reducing ability of plasma (FRAP), and trolox equivalent antioxidant capacity (TEAC). The thiobarbituric acid reactive substance (TBARS) measured formation of oxidants, and an oxidative stress index (OSI) was calculated by TBARS/(TEAC + FRAP). Ascorbate concentration was measured in dietary eucalypt leaves from Mount Lofty Ranges and Moggill. Results showed that in diseased Mount Lofty Ranges and Moggill koalas, plasma α-tocopherol concentrations were significantly lower, and ascorbate, TBARS, and OSI was significantly higher compared with clinically healthy koalas from Kangaroo Island. Ascorbate was high in eucalypt leaves, particularly young leaves from the Mount Lofty Ranges. This study showed that disease was associated with some measures of poor antioxidant capacity in koalas and also found that ascorbate is high in the dietary eucalypts of koalas.

Vitamin D metabolism in dogs and cats and its relation to diseases not associated with bone metabolism

Due to the presence of receptors in the cells of numerous body tissues, vitamin D is associated with several physiological functions that go beyond calcium and phosphorus homoeostasis and control of bone metabolism in the body. In humans, several studies have associated lower vitamin D concentrations with numerous diseases, such as cancer, heart disease, autoimmune diseases and infectious diseases, and also with an increase in the total mortality rate of the population. Recently, this nutrient started to gain importance in veterinary medicine, and several articles have shown a correlation between low vitamin D status and diseases unrelated to bone metabolism. The present review aims to highlight the recent publications that investigated this relationship, bringing the evidence that exists so far in dogs and cats.

Current knowledge of vitamin D in dogs

There is emerging interest in linking vitamin D status to physiological health and disease states in the dog, as evidenced by the recent increase in publications in this area. This research has most likely been spurred by the studies exploring vitamin D and disease in humans. However, there are important differences in vitamin D intake and metabolism between humans and dogs that should be accounted for. The understanding of basic vitamin D metabolism and the relationship between vitamin D intake and vitamin D status in dogs remains even more limited than current knowledge in humans. This review will summarize current knowledge of vitamin D in the dog, including metabolism and dietary recommendations. Emphasis is placed on the limitations to current knowledge. Studies investigating links between vitamin D and disease will be discussed in light of this knowledge. Suggestions for future research, including the development of reference ranges to define blood vitamin D sufficiency, are provided.

The Role of Thiamine and Effects of Deficiency in Dogs and Cats

Recent pet food recalls for insufficient dietary thiamine have highlighted the importance of adequate thiamine intake in dogs and cats, as thiamine is an essential dietary nutrient with a critical role in energy metabolism. Prolonged thiamine deficiency leads to clinical signs that can span several organ systems, and deficiency can be fatal if not reversed. In this review, the current knowledge of thiamine metabolism will be summarized. Dietary recommendations for dogs and cats will be discussed, and the risk factors and clinical signs associated with thiamine deficiency will be examined.

Influence of Various Factors on Circulating 25(OH) Vitamin D Concentrations in Dogs with Cancer and Healthy Dogs

Background

Low blood 25‐hydroxyvitamin D (25(OH)D) concentrations have been associated with cancer in dogs. Little research has examined what other factors may affect 25(OH)D concentrations.

Objectives

(1) To determine whether the presence of cancer (lymphoma, osteosarcoma, or mast cell tumor [MCT]) in dogs is associated with plasma 25(OH)D concentrations and (2) identify other factors related to plasma 25(OH)D concentrations in dogs.

Animals

Dogs newly diagnosed with osteosarcoma (n = 21), lymphoma (n = 27), and MCT (n = 21) presented to a tertiary referral oncology center, and healthy, client‐owned dogs (n = 23).

Methods

An observational study design was used. Dietary vitamin D intake, sex, age, body condition score (BCS), muscle condition score (MCS), and plasma concentrations of 25(OH)D, 24,25‐dihydroxyvitamin D (24,25(OH)₂D) (a marker of CYP24A1 activity), as well as ionized calcium (ICa), parathyroid hormone, and parathyroid hormone‐related protein concentrations were measured. An analysis of covariance was used to model plasma 25(OH)D concentrations.

Results

Cancer type (P = 0.004), plasma 24,25(OH)₂D concentrations (P < 0.001), and plasma ICa concentrations (P = 0.047) had significant effects on plasma 25(OH)D concentrations. Effects of age, sex, body weight, BCS, MCS, and plasma PTH concentrations were not identified. A significant interaction between ICa and cancer was found (P = 0.005). Plasma 25(OH)D concentrations increased as ICa concentrations increased in dogs with cancer, whereas plasma 25(OH)D concentrations decreased as ICa concentrations increased in healthy dogs.

Conclusions and Clinical Importance

Results support a relationship between cancer and altered vitamin D metabolism in dogs, mediated by plasma ICa concentrations. The CYP24A1 activity and plasma ICa should be measured in studies examining plasma 25(OH)D concentrations in dogs.

Plasma alpha-tochopherol determined by HPLC in dogs at different stages of chronic kidney disease: a retrospective study

The aim of the present study was to investigate retrospectively the plasma concentration of alpha-tocopherol in dogs with naturally acquired chronic kidney disease (CKD), at different stages of severity. Forty dogs (CKD group) with different stages of CKD (IRIS 1 n=12, IRIS 2 n=8, IRIS 3 n=11, IRIS 4 n=9) and 20 clinically healthy dogs were considered. Plasma alpha-tocopherol was assessed in both groups through high performance liquid chromatography (HPLC). Dogs of CKD group showed significantly lower (p=0.0002) levels of plasma alpha-tocopherol compared with clinically healthy dogs. A significant difference (p<0.04) in the number of patients with plasma alpha-tocopherol > or ≤ 21.5 ppm was found in CKD patients at different stages of severity. No significant correlation between plasma levels of alpha-tocopherol and plasma creatinine was found. In the present study, dogs affected by spontaneous CKD showed significantly lower plasma concentrations of alpha-tocopherol compared with clinically healthy dogs. Plasma alpha-tocopherol deficiency seems to be more severe in IRIS stage 1 and 4, compared with IRIS stage 2 and 3. The finding of marked alpha-tocopherol deficiency in patients in IRIS stage 1 should encourage further studies on the early use of prescription renal diet and antioxidant in this group of patients.

Association of Vitamin D Metabolites with Parathyroid Hormone, Fibroblast Growth Factor-23, Calcium, and Phosphorus in Dogs with Various Stages of Chronic Kidney Disease

BACKGROUND

Hypovitaminosis D is associated with progression of renal disease, development of renal secondary hyperparathyroidism (RHPT), chronic kidney disease-mineral bone disorder (CKD-MBD), and increased mortality in people with CKD. Despite what is known regarding vitamin D dysregulation in humans with CKD, little is known about vitamin D metabolism in dogs with CKD.

OBJECTIVES

The purpose of our study was to further elucidate vitamin D status in dogs with different stages of CKD and to relate it to factors that affect the development of CKD-MBD, including parathyroid hormone (PTH), fibroblast growth factor-23 (FGF-23), calcium, and phosphorus concentrations.

METHODS

Thirty-seven dogs with naturally occurring CKD were compared to 10 healthy dogs. Serum 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)₂ D], and 24,25-dihydroxyvitamin D [24,25(OH)₂ D], and PTH and FGF-23 concentrations were measured. Their association with serum calcium and phosphorus concentrations and IRIS stage was determined.

RESULTS

Compared to healthy dogs, all vitamin D metabolite concentrations were significantly lower in dogs with International Renal Interest Society (IRIS) stages 3 and 4 CKD (r [creatinine]: -0.49 to -0.60; P < .05) but not different in dogs with stages 1 and 2 CKD. All vitamin D metabolites were negatively correlated with PTH, FGF-23, and phosphorus concentrations (r: -0.39 to -0.64; P < .01).

CONCLUSIONS AND CLINICAL IMPORTANCE

CKD in dogs is associated with decreases in all vitamin D metabolites evaluated suggesting that multiple mechanisms, in addition to decreased renal mass, affect their metabolism. This information could have prognostic and therapeutic implications.

Plasma vitamin D metabolites and C-reactive protein in stage-stop racing endurance sled dogs

Background

Dogs are a unique model for examining the effects of exercise on vitamin D status because of their lack of vitamin D synthesis by UV exposure. In addition, the inflammatory response may be associated with hypovitaminosis D.

Objectives

To investigate the effects of several days of endurance exercise on plasma vitamin D (25‐(OH)D₃, 24,25‐(OH)D₃ and 1,25(OH)D₃) and serum C‐reactive protein (CRP) concentrations in stage‐stop racing sled dogs.

Animals

12 racing sled dogs and 8 control dogs.

Methods

Blood was collected before the race and immediately after racing on days 2 and 8. Plasma vitamin D metabolites and serum CRP concentrations were measured.

Results

Racing dogs showed a significant increase in 25(OH)D₃ on day 2 (P = .027) and day 8 of the race (P < .001), whereas no increases were observed in control dogs. The plasma concentration of 24,25(OH)D₃ showed a significant increase by day 8 (P < .001). There were no significant changes in 1,25(OH) D₃ concentrations across all time points and groups. Racing dogs had significantly increased CRP concentrations by day 2 (39.3 ± 30.1 μg/mL; P < .001).

Conclusions and Clinical Importance

Increases in vitamin D metabolites as well as increases in CRP concentrations were observed in racing sled dogs. This finding was contrary to the hypothesis that decreases in vitamin D status in athletes may be related to the acute phase inflammatory response during exercise. In addition, the increased 24,25(OH)D₃ concentrations compared to what is observed in other species suggests metabolic variations in dogs that lead to enhanced disposal of vitamin D.

Feline hyperparathyroidism: pathophysiology, diagnosis and treatment of primary and secondary disease

PRACTICAL RELEVANCE

Hyperparathyroidism exists in primary and secondary forms. Primary hyperparathyroidism has typically been considered a disease that uncommonly affects cats, but this condition is more prevalent than previous diagnoses would suggest. Secondary hyperparathyroidism may be caused by either nutritional influences (ie, nutritional secondary hyperparathyroidism) or chronic kidney disease (ie, renal secondary hyperparathyroidism). Tertiary hyperparathyroidism has yet to be documented in veterinary medicine, but it is possible that this condition occurs in some cats following longstanding renal secondary hyperparathyroidism.

CLINICAL CHALLENGES

Diagnosis of this group of calcium metabolic disorders presents a number of challenges for the clinician. For example, clinical signs can be non-specific and, especially in the case of primary hyperparathyroidism, there is often a low index of suspicion for the disease; careful sample handling is required for testing of parathyroid hormone (PTH) and ionized calcium levels; and there is currently no feline-specific assay for PTH, which has implications for test sensitivity and interpretation of results.

AIMS

This article briefly outlines PTH and calcium physiology by way of introduction to a review of PTH measurement and interpretation. Various forms of feline hyperparathyroidism are then described, encompassing diagnosis and treatment options.

Hypercobalaminaemia is associated with hepatic and neoplastic disease in cats: a cross sectional study

Background

When increased serum cobalamin concentrations are encountered clinically they are usually attributed to parenteral supplementation, dietary factors, or otherwise ignored. However, recently, hypercobalaminaemia has been associated with numerous diseases in humans, most notably neoplastic and hepatic disorders. The aim of this retrospective, observational, cross-sectional study was to determine the significance of increased cobalamin in cats.

Results

In total, 237 records were retrieved and 174 cats, of various ages and sexes met the inclusion criteria. A total of 42 cats had increased serum cobalamin concentration, and had not received prior supplementation. Multiple logistic regression analysis revealed that increased serum cobalamin concentration was positively related to pedigree breed (pedigree breeds more likely to have increased cobalamin concentration, odds ratio [OR] 4.24, 95% CI 1.78-10.15, P = 0.001), to having liver disease (OR 9.91, 95% CI 3.54-27.68), and to having a solid neoplasm (OR 8.54, 95% CI 1.10-66.45).

Conclusions

The results of the current study suggest that increased serum cobalamin concentrations should not be ignored in cats with no history of supplementation, and investigation for underlying hepatic or neoplastic disease is warranted.

Calcitriol, calcidiol, parathyroid hormone, and fibroblast growth factor-23 interactions in chronic kidney disease

Objective

To review the inter-relationships between calcium, phosphorus, parathyroid hormone (PTH), parent and activated vitamin D metabolites (vitamin D, 25(OH)-vitamin D, 1,25(OH)₂-vitamin D, 24,25(OH)₂-vitamin D), and fibroblast growth factor-23 (FGF-23) during chronic kidney disease (CKD) in dogs and cats.

Data Sources

Human and veterinary literature.

Human Data Synthesis

Beneficial effects of calcitriol treatment during CKD have traditionally been attributed to regulation of PTH but new perspectives emphasize direct renoprotective actions independent of PTH and calcium. It is now apparent that calcitriol exerts an important effect on renal tubular reclamation of filtered 25(OH)-vitamin D, which may be important in maintaining adequate circulating 25(OH)-vitamin D. This in turn may be vital for important pleiotropic actions in peripheral tissues through autocrine/paracrine mechanisms that impact the health of those local tissues.

Veterinary Data Synthesis

Limited information is available reporting the benefit of calcitriol treatment in dogs and cats with CKD.

Conclusions

A survival benefit has been shown for dogs with CKD treated with calcitriol compared to placebo. The concentrations of circulating 25(OH)-vitamin D have recently been shown to be low in people and dogs with CKD and are related to survival in people with CKD. Combination therapy for people with CKD using both parental and activated vitamin D compounds is common in human nephrology and there is a developing emphasis using combination treatment with activated vitamin D and renin-angiotensin-aldosterone-system (RAAS) inhibitors.

Serum homocysteine and methylmalonic acid concentrations in Chinese Shar-Pei dogs with cobalamin deficiency

Cobalamin deficiency is suspected to be hereditary in Chinese Shar-Pei dogs (Shar-Peis), and inherited causes of cobalamin deficiency may affect the cellular processing of cobalamin. In humans, a defect of the two main cobalamin-dependent intracellular enzymes (i.e., methionine synthase and methylmalonyl-CoA mutase) may lead to hyperhomocysteinemia and hypermethylmalonic acidemia. The aim of this retrospective study was to evaluate serum homocysteine (HCY) and methylmalonic acid (MMA) concentrations in cobalamin-deficient Shar-Peis and dogs of six other breeds. Serum samples (n=297) from cobalamin-deficient dogs (Shar-Peis, German Shepherd dogs, Labrador Retrievers, Yorkshire Terriers, Boxers, Cocker Spaniels, and Beagles) were analyzed for serum HCY and MMA concentrations. A Fisher's exact test was used to evaluate if cobalamin deficiency in Shar-Peis is associated with hyperhomocysteinemia. Serum HCY and MMA concentrations were higher in cobalamin-deficient Shar-Peis compared to cobalamin-deficient dogs of the six other breeds (P<0.0001). Hyperhomocysteinemia was associated with cobalamin deficiency in Shar-Peis (P=0.009). In addition, serum HCY and MMA concentrations did not differ between cobalamin-deficient German Shepherd dogs with and without exocrine pancreatic insufficiency (EPI), a potential cause of secondary cobalamin deficiency. These findings suggest that the function of the two intracellular cobalamin-dependent enzymes is impaired in Shar-Peis with cobalamin deficiency.

Chronic kidney disease in dogs and cats

Chronic kidney disease (CKD) occurs commonly in older dogs and cats. Advances in diagnostics, staging, and treatment are associated with increased quality and quantity of life. Dietary modification has been shown to increase survival and quality of life and involves more than protein restriction as diets modified for use with CKD are lower in phosphorous and sodium, potassium and B-vitamin replete, and alkalinizing, and they contain n3-fatty acids. Additionally, recognition and management of CKD-associated diseases such as systemic arterial hypertension, proteinuria, and anemia benefit patients. This article summarizes staging and management of CKD in dogs and cats.