Gestational Diabetes Mellitus with Diabetic Ketoacidosis in a Yorkshire Terrier Bitch

"My Bitch Is Empty!" An Overview of the Reasons for Pregnancy Loss in Dogs

The purpose of this review is to present reasons for pregnancy loss in dogs. Termination of pregnancy can occur at any stage of gestation, sometimes even before pregnancy is diagnosed. If embryonic death occurs before day 35 of gestation, the embryo is absorbed. Fetal death in the second half of gestation leads to abortion or fetal emphysema, maceration, or mummification. Abnormal embryonic development, competition between placental sites, or genetic abnormalities of the embryo(s) can lead to termination of pregnancy. Maternal factors that alter ovarian function or the environment in the oviducts and uterus, such as cystic endometrial hyperplasia or inflammation, can lead to pregnancy loss. Abnormalities of the placenta, uterine torsion, metrocoele, environmental stress, and malnutrition can have detrimental effects on fetal development. Several drugs or medications can also have embryotoxic/teratogenic effect. Endocrinological disorders such as hypoluteodism, gestational diabetes, and hypothyroidism can be reasons for pregnancy failure. Several bacteria, protozoa, and viruses can cause pregnancy loss in dogs. Etiological diagnoses of pregnancy loss in dogs are challenging as the exact causes are not always obvious; so, a multi-faceted approach is required.

Etiology and Pathophysiology of Diabetes Mellitus in Dogs

Canine diabetes results from a wide spectrum of clinical pathophysiological processes that cause a similar set of clinical signs. Various causes of insulin deficiency and beta cell loss, insulin resistance, or both characterize the disease, with genetics and environment playing a role. Understanding the genetic and molecular causes of beta cell loss will provide future opportunities for precision medicine, both from a therapeutic and preventative perspective. This review presents current knowledge of the etiology and pathophysiology of canine diabetes, including the importance of disease classification. Examples of potential targets for future precision medicine-based approaches to therapy are discussed.

Metabolomics during canine pregnancy and lactation

During pregnancy and parturition, female dogs have to cope with various challenges such as providing nutrients for the growth of the fetuses, hormonal changes, whelping, nursing, milk production, and uterine involution. Metabolomic research has been used to characterize the influence of several factors on metabolism such as inter- and intra-individual factors, feeding, aging, inter-breed differences, drug action, behavior, exercise, genetic factors, neuter status, and pathologic processes. Aim of this study was to identify metabolites showing specific changes in blood serum at the different phases of pregnancy and lactation. In total, 27 privately owned female dogs of 21 different breeds were sampled at six time points: during heat, in early, mid and late pregnancy, at the suspected peak of lactation and after weaning. A validated and highly automated canine-specific NMR metabolomics technology was utilized to quantitate 123 measurands. It was evaluated which metabolite concentrations showed significant changes between the different time points. Metabolites were then grouped into five clusters based on concentration patterns and biochemical relationships between the metabolites: high in mid-pregnancy, low in mid-pregnancy, high in late pregnancy, high in lactation, and low in lactation. Several metabolites such as albumin, glycoprotein acetyls, fatty acids, lipoproteins, glucose, and some amino acids show similar patterns during pregnancy and lactation as shown in humans. The patterns of some other parameters such as branched-chain amino acids, alanine and histidine seem to differ between these species. For most metabolites, it is yet unstudied whether the observed changes arise from modified resorption from the intestines, modified production, or metabolism in the maternal or fetal tissues. Hence, further species-specific metabolomic research may support a broader understanding of the physiological changes caused by pregnancy that are likely to be key for the normal fetal growth and development. Our findings provide a baseline of normal metabolic changes during healthy canine pregnancy and parturition. Combined with future metabolomics findings, they may help monitor vital functions of pre-, intra-, and post-partum bitches and may allow early detection of illness.

Effect of maternal metabolism on fetal supply: Glucose, non-esterified fatty acids and beta-hydroxybutyrate concentrations in canine maternal serum and fetal fluids at term pregnancy

The progressive adaptations in carbohydrate and lipid metabolism during canine pregnancy are reflected in the concentrations of glucose, non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB). The levels of these metabolites in the bitch likely affect fetal concentrations and the composition of amniotic and allantoic fluids (AMF and ALF, respectively). We studied 31 canine parturitions (Cesarean sections) and found that glucose, NEFA and BHB concentrations were significantly higher in maternal serum than in AMF or ALF. Glucose levels in maternal serum, AMF and ALF were closely related (R² ≥ 0.821, P < 0.0001) as well as serum and AMF BHB levels (R² = 0.661, P < 0.0001). In maternal serum, increases in NEFA were associated with increased BHB, and both were negatively related to glucose (P ≤ 0.010). To estimate the effect of the metabolic burden of pregnancy, we evaluated these variables in relation to the dam's body weight and to the ratio of litter weight to the dam's body weight (LW/BW). Maternal serum glucose was not influenced by LW/BW, but it was lower in small than in large/giant bitches. Small breed dogs and those with >10% LW/BW had significantly higher serum NEFA and BHB concentrations. Glucose in AMF and ALF was independent of LW/BW (P ≥ 0.399). AMF NEFA was lower and BHB higher, if LW/BW was >10% (P ≤ 0.048). In conclusion, the extent of the metabolic load of pregnancy in bitches depends on breed size and on the ratio of litter weight to dam's body weight. Maternal concentrations of glucose, BHB and NEFA determine the concentrations of these metabolites in fetal fluids.

Use of aglepristone for the treatment of P4 induced insulin resistance in dogs

Insulin resistance (IR) in dogs is suspected when hyperglycemia is present despite administration of insulin doses greater than 1.0 to 1.5 UI/kg. IR is caused by increases in counter regulatory hormones concentrations (glucagon, glucocorticoids, catecholamines and growth hormone). This study was conducted to investigate the use of aglepristone (RU 46534), a P4 receptor antagonist, for the treatment of IR diabetes mellitus in bitches during the luteal phase. All animals were treated with porcine insulin zinc suspension (Caninsulin) and aglepristone (Alizin) 10 mg/kg subcutaneously at day 1, 2, 9 and 17 from diagnosis. At day 5, no significant variation in glycemia was shown. At day 12 and 20, serum glucose concentrations were significant lower (p < 0.05). From day 12 the insulin dose was reduced to 0.8 IU BID. Insulin was reduced in the following weeks and glycemia was controlled.

Food intake and nutrition during pregnancy, lactation and weaning in the dam and offspring

In mammalian species, the connection between reproduction and nutrition is undeniable and illustrated by numerous publications: its role concerning regulation of hormonal secretions, fertility, pregnancy outcome, lactation and neonatal development indeed retains the attention of the scientific community. The interest on the influence of nutrition in dog and cat reproductive physiology is growing. Awareness on the key aspects of feeding during critical periods like pregnancy, lactation and weaning is essential to optimize the reproductive performances in these species.