Possible causes of diabetes mellitus in cattle infected with bovine viral diarrhoea virus

Effects of xenin-25 on insulin and glucagon secretions in healthy conscious sheep

The aim of present study was to determine effect of an intravenous injection of xenin-25 on insulin and glucagon secretion in healthy conscious sheep. After feeding once at 17:00, the experiment was started from 9:00 on the next day. Xenin-25 was intravenously (i.v.) injected at a dose of 100 to 1000 pmol/kg with and without the simultaneous injection of glucose at a dose of 200 μmol/kg, and blood was withdrawn before and after the injections. A single xenin-25 injection at 100 and 300 pmol/kg significantly increased the plasma insulin concentration, whereas the 1000 pmol/kg dose did not elicit significantly enhanced insulin response. Plasma glucose and glucagon concentrations did not significantly change after a single xenin-25 injection. Xenin-25 injection significantly and dose-dependently augmented the glucose-induced insulin secretion. However, the changes in the plasma glucose and glucagon level after the glucose injection were not altered by xenin injection. A prior intravenous injection of the neurotensin receptor subtype-1 (NTR-1) antagonist SR 48692 at 100 nmol/kg did not modify the glucose-induced change in plasma insulin caused by xenin-25 at 300 pmol/kg, and intravenous injection of the NTR-2 agonist levocabastine at 1000 pmol/kg did not augment the insulin response to the glucose injection. On the other hand, no xenin-25 immunopositive cells were detected in the ovine pancreas. The mRNAs of the three NTR subtypes were highly expressed in the ovine pancreas in comparison with the expression in the abomasum. These results suggest that xenin-25 released from the upper gastrointestinal tract plays a role of an insulinotropic factor in sheep, possibly through NTRs in the pancreatic islets, but not via NTR-2.

Applications of mesenchymal stem cell technology in bovine species

Mesenchymal stem cells (MSCs) have received a great deal of attention over the past 20 years mainly because of the results that showed regeneration potential and plasticity that were much stronger than expected in prior decades. Recent findings in this field have contributed to progress in the establishment of cell differentiation methods, which have made stem cell therapy more clinically attractive. In addition, MSCs are easy to isolate and have anti-inflammatory and angiogenic capabilities. The use of stem cell therapy is currently supported by scientific literature in the treatment of several animal health conditions. MSC may be administered for autologous or allogenic therapy following either a fresh isolation or a thawing of a previously frozen culture. Despite the fact that MSCs have been widely used for the treatment of companion and sport animals, little is known about their clinical and biotechnological potential in the economically relevant livestock industry. This review focuses on describing the key characteristics of potential applications of MSC therapy in livestock production and explores the themes such as the concept, culture, and characterization of mesenchymal stem cells; bovine mesenchymal stem cell isolation; applications and perspectives on commercial interests and farm relevance of MSC in bovine species; and applications in translational research.

Redox disequilibrium vis-a-vis inflammatory cascade mediation of lymphocyte dysfunction, apoptosis, cytokine expression and activation of NF-κB in subclinical diabetic goats

Molecular basis of diabetes induced oxidative stress and immune dysfunction have not been reported in animal science. The present study envisages same in subclinical diabetic (SCD) goats (6) diagnosed on biochemical and histopathological basis in reference to non-diabetic (NSCD) goats (6). Oxidative stress indices were analyzed by manual methods. The concentration of reduced glutathione (GSH) and the activity of superoxide dismutase (SOD) was significantly lower in SCD goats than in NSCD goats; whereas the lipid peroxide (LPO) was higher in SCD. Catalase (CAT) activity was nonsignificantly lower in SCD goats than NSCD goats. SCD goats had significantly lower lymphocyte stimulation index by cell culture and higher apoptotic cell percentage by flow cytometry than NSCD goats. The concentration of the transforming growth factor beta 1 (TGF-β1) by ELISA was significantly higher in SCD goats than in NSCD. The expressions of tumour necrosis factor alpha (TNF-α) and interleukin 8 (IL 8) by RT-PCR were higher in SCD goats than in non-diabetic ones. Expression of transcription factor (NF-κB) by western blot was significantly higher in SCD goats than NSCD goats. Fall of antioxidants (GSH, SOD, catalase) and rise of oxidants (LPO) suggest oxidative stress. Decrease of immune cell function, rise of inflammatory cytokines and transcription factors suggest immune dysfunction. Hence it was concluded that SCD induced oxidative stress and impairment of immunity in goats, which was most likely associated with depletion of antioxidants, increase of oxidants and inflammatory mediators. NF-κB, most likely have played a mediatory role in coordinating these intricate responses.

Amyloidogenicity, Cytotoxicity, and Receptor Activity of Bovine Amylin: Implications for Xenobiotic Transplantation and the Design of Nontoxic Amylin Variants

Islet amyloid formation contributes to β-cell death and dysfunction in type-2 diabetes and to the failure of islet transplants. Amylin (islet amyloid polypeptide, IAPP), a normally soluble 37 residue polypeptide hormone produced in the pancreatic β-cells, is responsible for amyloid formation in type-2 diabetes and is deficient in type-1 diabetes. Amylin normally plays an adaptive role in metabolism, and the development of nontoxic, non-amyloidogenic, bioactive variants of human amylin are of interest for use as adjuncts to insulin therapy. Naturally occurring non-amyloidogenic variants are of interest for xenobiotic transplantation and because they can provide clues toward understanding the amyloidogenicity of human amylin. The sequence of amylin is well-conserved among species, but sequence differences strongly correlate with in vitro amyloidogenicity and with islet amyloid formation in vivo. Bovine amylin differs from the human peptide at 10 positions and is one of the most divergent among known amylin sequences. We show that bovine amylin oligomerizes but is not toxic to cultured β-cells and that it is considerably less amyloidogenic than the human polypeptide and is only a low-potency agonist at human amylin-responsive receptors. The bovine sequence contains several nonconservative substitutions relative to human amylin, including His to Pro, Ser to Pro, and Asn to Lys replacements. The effect of these substitutions is analyzed in the context of wild-type human amylin; the results provide insight into their role in receptor activation, the mode of assembly of human amylin, and the design of soluble amylin analogues.

Distribution pattern of bovine viral diarrhoea virus type 1 genome in lymphoid tissues of experimentally infected sheep

In this study, cellular localization and the distribution pattern of BVDV genome in lymphoid tissues during the course of experimental acute BVDV-1 infection of sheep was investigated. Tonsils, mesenteric lymph nodes (MLN) and spleen were collected on 3, 6, 9, 12 and 15 days post infection (dpi) from twenty 4-month-old lambs, experimentally inoculated intra-nasally with 5 × 10(5) TCID50 of a non-cytopathic (ncp) BVDV-1 isolate, Ind-17555. Tissues collected from ten mock-infected lambs served as controls. In situ hybridization (ISH) was carried out in paraformaldehyde fixed paraffin embedded tissue sections using digoxigenin labelled riboprobe targeting 5'-UTR of BVDV-1. BVDV genome was detected at all the intervals from 3 dpi to 15 dpi in the lymphoid tissues with variations between the intervals and also amongst the infected sheep. During the early phase of acute infection, presence of viral genome was more in tonsils than MLN and spleen, whereas the distribution was higher in MLN during later stages. BVDV-1 genome positive cells included lymphocytes, macrophages, plasma cells, reticular cells and sometimes crypt epithelial cells. Genome distribution was frequently observed in the lymphoid follicles of tonsils, MLN and spleen, besides the crypt epithelium in tonsils, paracortex and medullary sinus and cords of MLN. Most abundant and widespread distribution of BVDV-1 genome was observed on 6 dpi while there was a reduction in number and intensity of positive signals by 15 dpi in most of the infected animals. This is the first attempt made to study the localisation of BVDV-1 in lymphoid tissues of acutely infected sheep by in situ hybridization. The results show that the kinetics of BVDV-1 distribution in lymphoid tissues of experimentally infected non-pregnant sheep follows almost a similar pattern to that demonstrated in BVDV infected cattle.

Alteration in clinico-biochemical profile and oxidative stress indices associated with hyperglycaemia with special reference to diabetes in cattle--a pilot study

The present study aimed to assess hyperglycaemia with special reference to diabetes mellitus in cattle by clinico-biochemical estimation and evaluation of oxidative stress indices. A total of 256 cattle exhibiting weakness, poor body condition and reduced milk yield in lactating cattle were included in the study. These animals were screened with blood glucose level, urine glucose and ketone bodies. Out of these, 32 (12.5%) cattle showed hyperglycaemia and glycosuria, of which 25% exhibited ketonuria. Diabetes was confirmed in five cattle by estimation of fasting blood glucose, glycated haemoglobin, serum fructosamine, intravenous glucose tolerance test and insulin level. This reports first confirmation of diabetes in cattle in India. All these five animals revealed low level of serum insulin suggestive of insulin-dependent diabetes mellitus in cattle. The level of aspartate aminotransferase (AST) and gamma glutamyl transferase (GGT) was found to be increased in diabetic cattle. Oxidant/antioxidant balance was assessed in hyperglycaemic cattle and five age-matched Holstein Friesian (HF) cross-bred healthy control animals. Diabetic cattle revealed significantly higher (P ≤ 0.01) levels of erythrocytic lipid peroxides in comparison with other hyperglycaemic cattle and healthy controls whereas the level of superoxide dismutase (SOD) and catalase was found to be significantly lower in diabetes-affected animals in comparison to healthy controls. Reduced glutathione did not show a significant difference between hyperglycaemic and control groups. It is concluded from the present study that oxidative stress associated with diabetes in cattle is obvious compared with other hyperglycaemic cattle.