Healthy Research Cats Research Articles

Sedation with dexmedetomidine decreases skin perfusion in cats.

To evaluate skin perfusion in cats receiving dexmedetomidine compared to a placebo. 9 healthy adult research cats. A randomized, blinded, placebo-controlled study design was used. Two sites, the dorsal metatarsus (site: limb) and lateral flank (site: flank), were evaluated with laser speckle contrast imaging (LSCI) at baseline and following administration of dexmedetomidine (1, 3, or 5 mcg/kg, IV) or a placebo (0.9% saline, IV). Mean speckle contrast (MSC), a surrogate for perfusion, was obtained from LSCI and compared between treatments. Heart rate, sedation score, and body temperature were recorded. Skin perfusion to the flank and limb, reported as MSC, was assessed via LSCI at baseline and at 5, 10, and 15 minutes posttreatment. There was a significant decrease in heart rate (P < .001) in cats receiving 1, 3, and 5 mcg/kg dexmedetomidine compared to placebo. There was a significant increase in median sedation score at all time points postsedation compared to baseline (P < .018). Changes in MSC for the metatarsus were not significantly different between treatments at any time point (P = .12). For the flank, MSC was significantly higher for cats treated with dexmedetomidine compared to baseline (P ≤ .01). Skin perfusion to the flank decreased as early as 5 minutes posttreatment with dexmedetomidine and persisted for at least 15 minutes, regardless of dexmedetomidine dose. Dexmedetomidine decreased skin perfusion in cats, even at low doses. Veterinarians may elect for an alternative sedative medication when decreased skin perfusion is a concern.

Respiratory dysbiosis in cats with spontaneous allergic asthma.

Deviations from a core airway microbiota have been associated with the development and progression of asthma as well as disease severity. Pet cats represent a large animal model for allergic asthma, as they spontaneously develop a disease similar to atopic childhood asthma. This study aimed to describe the lower airway microbiota of asthmatic pet cats and compare it to healthy cats to document respiratory dysbiosis occurring with airway inflammation. We hypothesized that asthmatic cats would have lower airway dysbiosis characterized by a decrease in richness, diversity, and alterations in microbial community composition including identification of possible pathobionts. In the current study, a significant difference in airway microbiota composition was documented between spontaneously asthmatic pet cats and healthy research cats mirroring the finding of dysbiosis in asthmatic humans. Filobacterium and Acinetobacter spp. were identified as predominant taxa in asthmatic cats without documented infection based on standard culture and could represent pathobionts in the lower airways of cats. Mycoplasma felis, a known lower airway pathogen of cats, was identified in 35% of asthmatic but not healthy cats. This article has been published alongside “Temporal changes of the respiratory microbiota as cats transition from health to experimental acute and chronic allergic asthma” (1).

Effect of repeated administration of a parenteral feline herpesvirus-1, calicivirus, and panleukopenia virus vaccine on select clinicopathologic, immunological, renal histologic, and immunohistochemical parameters in healthy adult cats.

To assess whether hyperinoculation of cats with a feline herpesvirus-1, calicivirus, and panleukopenia virus (FVRCP) vaccine could be used as a model to study interstitial nephritis and to assess humoral and cell-mediated immune responses toward vaccinal α-enolase. 6 healthy young adult purpose-bred research cats. Baseline renal cortical biopsies, whole blood, serum, and urine were collected prior to administration of a commercial FVRCP parenteral vaccine. Vaccine hyperinoculation was defined as a total of 8 vaccinations given at 2-week intervals over a 14-week period. Blood samples were collected immediately prior to each vaccination, and a second renal biopsy was performed 2 weeks after hyperinoculation (week 16). Renal histopathology, renal α-enolase immunohistochemistry, and assays to detect humoral and cell-mediated immune reactions against Crandell-Rees feline kidney (CRFK) cell lysates and α-enolase were performed. An α-enolase immunoreactivity score for renal tubules and glomeruli based on signal intensity was determined by a blinded pathologist. Hyperinoculation with the vaccine was not associated with clinicopathologic evidence of renal dysfunction, and interstitial nephritis was not recognized by light microscopy in the time studied. The mean serum absorbance values for antibodies against CRFK antigen and α-enolase were significantly (P < 0.001) higher at weeks 4, 8, and 16 versus week 0. Renal tubular and glomerular α-enolase immunoreactivity scores were higher at week 16 compared to baseline. Findings suggested that systemic immunological reactions occurred and renal tissues were affected by vaccine hyperinoculation; however, short-term FVRCP vaccine hyperinoculation cannot be used to study interstitial nephritis in cats.

Intravenous iron sucrose is safe but does not prevent development of anemia or iron deficiency in healthy cats undergoing serial venipuncture.

To evaluate IV iron sucrose safety and impact on hematologic and iron indices in healthy cats. 5 healthy research cats. Cats were administered iron sucrose (0.5 mg/kg, IV) over 30 minutes. Monitoring for acute reactions (temperature, heart rate, respiratory rate, and blood pressure) was performed every 5 minutes during injection and every 15 minutes for an additional hour. Baseline, 24-hour, and 1-, 2-, and 3-week postinjection measurements of CBC with reticulocyte indices, iron panel (ferritin, total iron-binding capacity, and iron), calculated transferrin saturation (TSAT), and serum amyloid A (SAA) concentration were performed. No cat experienced an acute drug reaction. SAA concentration was increased at 24 hours versus baseline. TSAT and ferritin decreased over time, with 3 cats developing concurrent functional iron deficiency (FID) and anemia. Hct (Spearman correlation [rs] = 0.805), hemoglobin (rs = 0.770), and reticulocyte hemoglobin content (rs = 0.581) correlated with TSAT. IV iron sucrose was well tolerated in healthy cats but was associated with transient increase in the systemic inflammatory marker SAA. Efficacy evaluation of dose based on iron deficit is needed in sick cats. Despite cumulative blood draw volume below recommended limits, anemia and FID were observed, which has important implications for experimental designs and serial hematologic monitoring. Further evaluation of inflammatory response to IV iron sucrose administration is warranted.

Effects of Butorphanol With Alfaxalone or Dexmedetomidine on Feline Splenic Size and Appearance on Ultrasound and Computed Tomography.

The purpose of the study was to determine the effects of intramuscular butorphanol with dexmedetomidine or alfaxalone on feline splenic size, echogenicity, and attenuation using ultrasound and computed tomography (CT). Ten healthy research cats underwent ultrasound and CT without sedation (controls), 15 min after protocol AB (alfaxalone 2 mg/kg and butorphanol 0.2 mg/kg) and 10 min after protocol DB (dexmedetomidine 7 μg/kg and butorphanol 0.2 mg/kg), with a one-week wash-out period between each sedation, using a cross-over study design. Images were randomized and anonymized for evaluation by a board-certified radiologist. On ultrasound, the sedative protocols affected splenic thickness, at the body and the tail (p = 0.002 and 0.0003, respectively). Post-hoc tests revealed that mean ± SEM thickness was greater after AB (body: 10.24 ± 0.30 mm; tail: 7.96 ± 0.33 mm) than for the control group (body: 8.71 ± 0.30 mm; tail: 6.78 ± 0.33 mm), while no significant difference was observed following DB. Splenic echogenicity was unchanged between treatments (p = 0.55). On CT, mean ± SEM splenic volume was increased after AB (37.82 ± 1.91 mL) compared to the control group (20.06 ± 1.91 mL) (p < 0.0001), but not after DB (24.04 ± 1.91 mL). Mean splenic attenuation increased after AB (p = 0.0009), but not DB. Protocol DB may be preferable for profound sedation in cats while avoiding changes in feline splenic imaging. When protocol AB is selected, splenomegaly should be expected, though mild on ultrasound. The increased splenic attenuation after AB is unlikely to be clinically relevant.

Administration of certain sedative drugs is associated with variation in sonographic and radiographic splenic size in healthy cats.

Ultrasonography and radiography are standard diagnostic tests for cats with suspected splenic disease, however published information on outside sources of variation are currently lacking. The purpose of this prospective, randomized, crossover group study was to evaluate effects of common sedative drugs on the sonographic and radiographic characteristics of the spleen in healthy cats. Fifteen healthy adult research cats were randomly assigned into one of three groups corresponding to different sequences of administration of five sedative drugs/drug combinations (acepromazine; butorphanol; dexmedetomidine; midazolam and butorphanol (MB); and dexmedetomidine, butorphanol, and ketamine (DBK)), administered at 1-week intervals. At each visit, three-view abdominal radiographic and ultrasonographic examinations were performed prior to sedation and repeated 15-30 min and 2-3h post sedation. Two board-certified radiologists (one ACVR and one ACVR/ECVDI) evaluated the anonymized and randomized images. Acepromazine resulted in significantly increased sonographic and radiographic splenic measurements from baseline, which remained significantly increased 2-3h post sedation. The mean magnitude of this change ranged from 0.9mm (tail height, SD 1.4mm) to 1.8mm (body height, SD 1.7mm) for ultrasound, and was 2.2mm (ventrodorsal width, SD 2.3mm) for radiographs. With butorphanol, there was no significant change in splenic size. For dexmedetomidine, MB, and DBK, there was a trend toward increased splenic size from baseline to the first post-sedation timepoint, which was statistically significant for radiographic measurements, although not for ultrasound. Findings indicated that acepromazine should be avoided prior to imaging while butorphanol may be used when sedation is needed in cats presenting for potential splenic disease.

Prolonged Anesthetic Recovery after Continuous Infusion of Midazolam in 2 Domestic Cats (Felis catus).

Two healthy research cats involved in a randomized, blinded prospective pharmacodynamics study evaluating midazolam continuous-rate infusion as a means to decrease sevoflurane concentrations experienced unexpectedly prolonged recoveries. Midazolam loading doses, infusion rates, and the targeted plasma midazolam concentrations at steady-state were determined by pharmacokinetic modeling based on the results of a preliminary pharmacokinetic study using a single dose of midazolam. In the pharmacodynamics study, cats remained oversedated after recovery from anesthesia, and plasma concentrations of midazolam and its primary metabolite (1-hydroxymidazolam) remained elevated. The use of flumazenil was unsuccessful in timely treatment of oversedation. Administration of intravenous lipid emulsion was used in one of the cats to facilitate recovery and appeared to be effective in both reducing the depth of midazolam-induced oversedation and significantly reducing the plasma concentration of 1-hydroxymidazolam. The effects after the administration of both treatment modalities on clinical signs and plasma drug concentrations in cats are discussed. The observations suggest that cats may eliminate 1-hydroxymidazolam more slowly than expected; consequently dose adjustments may be required when continuous infusion of midazolam is intended. In addition, intravenous lipid emulsion may facilitate recovery from midazolam oversedation, particularly in cases unresponsive to traditional treatment modalities. However, further investigations are warranted to delineate the efficacy of this modality in the treatment of midazolam oversedation.

Effects of a synbiotic on the fecal microbiome and metabolomic profiles of healthy research cats administered clindamycin: a randomized, controlled trial

ABSTRACT Reduction in antibiotic-associated gastrointestinal signs (AAGS) in people co-administered probiotics is believed to result from shifts in the microbiome and metabolome. Amelioration of AAGS in cats secondary to synbiotic administration has recently been demonstrated. Thus, the aim of this randomized, double-blinded, placebo-controlled trial was to characterize associated changes in the fecal microbiome and metabolome. Sixteen healthy research cats received clindamycin with food, followed 1 h later by either a placebo or synbiotic, daily for 21 days. Fecal samples were collected during baseline, antibiotic administration, and 6 weeks after antibiotic discontinuation. Sequencing of 16S rRNA genes was performed, and mass spectrometry was used to determine fecal metabolomic profiles. Results were compared using mixed-model analyses, with P < 0.05 considered significant. Alpha and beta diversity were altered significantly during treatment, with persistent changes in the Shannon and dysbiosis indices. The relative abundance of Actinobacteria (Adlercreutzia, Bifidobacterium, Collinsella, Slackia), Bacteroidia (Bacteroides, Prevotella), Ruminococcaceae (Faecalibacterium, Ruminococcus), Veillonellaceae (Megamonas, Megasphaera, Phascolarctobacterium) and Erysipelotrichaceae ([Eubacterium]) decreased and relative abundance of Clostridiaceae (Clostridium) and Proteobacteria (Enterobacteriaceae) increased during treatment, followed by variable return to baseline relative abundances. Derangements in short-chain fatty acid (SCFA), bile acid, tryptophan, sphingolipid, polyamine, benzoic acid, and cinnaminic acid pathways occurred with significant group by time, group, and time interactions for 10, 5, and 106 metabolites, respectively. Of particular note were changes related to polyamine synthesis. Further investigation is warranted to elucidate the role of these alterations in prevention of AAGS in cats, people, and other animals treated with synbiotics.

Effect of body position and time on quantitative computed tomographic measurements of lung volume and attenuation in healthy anesthetized cats.

OBJECTIVE To quantify the effect of time and recumbency on CT measurements of lung volume and attenuation in healthy cats under general anesthesia. ANIMALS 8 healthy research cats. PROCEDURES Anesthetized cats were positioned in sternal recumbency for 20 minutes and then in left, right, and left lateral recumbency (40 minutes/position). Expiratory helical CT scan of the thorax was performed at 0 and 20 minutes in sternal recumbency and at 0, 5, 10, 20, 30, and 40 minutes in each lateral recumbent position. For each lung, CT measurements of lung volume and attenuation and the extent of lung areas that were hyperaerated (-1,000 to -901 Hounsfield units [HU]), normoaerated (-900 to -501 HU), poorly aerated (-500 to -101 HU), or nonaerated (-100 to +100 HU [indicative of atelectasis]) were determined with a semiautomatic threshold-based technique. A restricted maximum likelihood analysis was performed. RESULTS In lateral recumbency, the dependent lung had significantly greater attenuation and a lower volume than the nondependent lung. Within the dependent lung, there was a significantly higher percentage of poorly aerated lung tissue, compared with that in the nondependent lung. These changes were detected immediately after positioning the cats in lateral recumbency and remained static with no further significant time-related change. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that once anesthetized healthy cats were positioned in lateral recumbency, the dependent lung lobes underwent a rapid reduction in lung volume and increase in lung attenuation that did not progress over time, predominantly attributable to an increase in poorly aerated lung tissue.

Pharmacokinetics of Single-Dose Oral Pregabalin Administration in Normal Cats.

Objective: To describe the pharmacokinetic parameters of oral pregabalin in normal cats after single oral dosing.Animals: Six healthy adult research cats.Procedures: Following sedation and indwelling catheter placement, one oral (4 mg/kg) dose of pregabalin was administered. Blood samples were collected at 0, 15 and 30 min and 1, 1.5, 2, 3, 4, 6, 8, 12, 24, and 36 h after administration. Plasma pregabalin concentrations were measured by high-performance liquid chromatography and subjected to pharmacokinetic analysis using commercial software.Results: Four of six cats developed moderate sedation after pregabalin administration. The peak pregabalin concentration was 8.3 ± 1.6 μg/ml which occurred at 2.9 ± 1.2 h. Elimination half-life was 10.4 ± 2.6 h and area under the curve was 133.9 ± 71.5 μg-h/ml. Time above the minimum therapeutic concentration for seizure control in dogs and people (2.8 μg/ml) was 17.6 ± 6.2 h. Using these data, predicted minimum, maximum and average steady state concentrations were calculated for 12 and 24 h dosing intervals.Conclusions and Clinical Relevance: Pregabalin (4 mg/kg) administered orally to cats results in plasma concentrations within the range considered to be efficacious for seizure control in dogs and humans between 1.5 and at least 12 h. Because of moderate sedative side effects in the majority of cats at this dose and high calculated maximum steady state concentrations, a lower dose, given more frequently (1–2 mg/kg q 12 h), should be evaluated in prospective clinical studies.

Short and long-term effects of a synbiotic on clinical signs, the fecal microbiome, and metabolomic profiles in healthy research cats receiving clindamycin: a randomized, controlled trial.

BackgroundAntibiotic-associated gastrointestinal signs (AAGS) occur commonly in cats. Co-administration of synbiotics is associated with decreased AAGS in people, potentially due to stabilization of the fecal microbiome and metabolome. The purpose of this double-blinded randomized-controlled trial was to compare AAGS and the fecal microbiome and metabolome between healthy cats that received clindamycin with a placebo or synbiotic.Methods16 healthy domestic shorthair cats from a research colony were randomized to receive 150 mg clindamycin with either a placebo (eight cats) or commercially-available synbiotic (eight cats) once daily for 21 days with reevaluation 603 days thereafter. All cats ate the same diet. Food consumption, vomiting, and fecal score were recorded. Fecal samples were collected daily on the last three days of baseline (days 5–7), treatment (26–28), and recovery (631–633). Sequencing of 16S rRNA genes and gas chromatography time-of-flight mass spectrometry was performed. Clinical signs, alpha and beta diversity metrics, dysbiosis indices, proportions of bacteria groups, and metabolite profiles were compared between treatment groups using repeated measures ANOVAs. Fecal metabolite pathway analysis was performed. P < 0.05 was considered significant. The Benjamini & Hochberg’s False Discovery Rate was used to adjust for multiple comparisons.ResultsMedian age was six and five years, respectively, for cats in the placebo and synbiotic groups. Hyporexia, vomiting, diarrhea, or some combination therein were induced in all cats. Though vomiting was less in cats receiving a synbiotic, the difference was not statistically significant. Bacterial diversity decreased significantly on days 26–28 in both treatment groups. Decreases in Actinobacteria (Bifidobacterium, Collinsella, Slackia), Bacteriodetes (Bacteroides), Lachnospiraceae (Blautia, Coprococcus, Roseburia), Ruminococcaceae (Faecilobacterium, Ruminococcus), and Erysipelotrichaceae (Bulleidia, [Eubacterium]) and increases in Clostridiaceae (Clostridium) and Proteobacteria (Aeromonadales, Enterobacteriaceae) occurred in both treatment groups, with incomplete normalization by days 631–633. Derangements in short-chain fatty acid, bile acid, indole, sphingolipid, benzoic acid, cinnaminic acid, and polyamine profiles also occurred, some of which persisted through the terminal sampling timepoint and differed between treatment groups.DiscussionCats administered clindamycin commonly develop AAGS, as well as short- and long-term dysbiosis and alterations in fecal metabolites. Despite a lack of differences in clinical signs between treatment groups, significant differences in their fecal metabolomic profiles were identified. Further investigation is warranted to determine whether antibiotic-induced dysbiosis is associated with an increased risk of future AAGS or metabolic diseases in cats and whether synbiotic administration ameliorates this risk.

Video‐assisted thoracoscopic thoracic duct sealing is inconsistent when performed with a bipolar vessel‐sealing device in healthy cats

To describe a technique for video-assisted thoracoscopic (VATS) thoracic duct ligation (TDL) in normal cats with a bipolar vessel-sealing device and to assess durability of the seal. Prospective case series. Six healthy research cats. Cats were placed under anesthesia for computed tomography lymphangiography (CTLA) to identify thoracic duct anatomy. On the basis of CTLA findings, cats were positioned in either right or left lateral recumbency for a 3-port VATS TDL. Thoracic duct branches were dissected from the aorta after subcutaneous indirect near-infrared fluorescence (NIRF) lymphography with indocyanine green was performed to optimize detection. A vessel-sealing device was used to seal each thoracic duct in 1 or more locations. Postattenuation, indirect NIRF lymphography was repeated to confirm complete occlusion of thoracic duct flow. CTLA was repeated in all cats 3 months postoperatively. The thoracic duct was surgically approached from the right in 3 cats and from the left in 3 cats. A median of 2.5 (range 1-6) TDL seal sites were applied. In 2 cats, leakage of chyle was detected during dissection. At 3 months postoperatively, CTLA confirmed reestablished chylous flow in 5 of 6 cats, appearing to occur through recanalization of previously sealed sites rather than through development of de novo lymphatic vessels. VATS TDL is feasible in cats, although the variable and delicate nature of feline thoracic duct anatomy should be considered preoperatively. Bipolar vessel-sealing devices are not a durable modality for thoracic duct sealing in healthy cats in a seal only fashion.

Randomized, Controlled, Crossover trial of Prevention of Clindamycin-Induced Gastrointestinal Signs Using a Synbiotic in Healthy Research Cats.

BackgroundSynbiotics often are prescribed to limit antibiotic‐associated gastrointestinal signs (AAGS) in cats, but data to support this recommendation are lacking.ObjectiveTo determine whether synbiotic co‐administration mitigates AAGS in healthy research cats treated with clindamycin.Animals16 healthy research cats.MethodsA randomized, double‐blinded, placebo‐controlled, 2‐way, 2‐period, crossover study with a 6‐week washout was performed. Each study period consisted of a 1‐week baseline and a 3‐week treatment period. Cats received 75 mg clindamycin with food once daily for 3 weeks, followed 1 hour later by either 2 capsules of a synbiotic or placebo. Food consumption, vomiting, fecal score, and completion of treatment were compared using repeated measures split plot or crossover designs with covariates, with P < 0.05 considered significant.ResultsCats that received the synbiotic were more likely to complete treatment in period 1 (100% vs. 50%, P = 0.04). Cats vomited less when receiving the synbiotic but this was not significant, but there were significant period effects (F‐value = 11.4, P < 0.01). Cats had higher food intake while receiving the synbiotic (F‐value = 31.1, P < 0.01) despite period effects (F‐value = 8.6, P < 0.01). There was no significant effect of treatment on fecal scores, which significantly increased over time (F‐value = 17.9, P < 0.01).Conclusions and Clinical ImportanceAdministration of a synbiotic 1 hour after clindamycin administration decreased hyporexia and vomiting in healthy cats. Additionally, significant period effects suggest that clinical benefits of synbiotic administration persist for at least 6 weeks after discontinuation, decreasing the severity of AAGS in cats that subsequently received clindamycin with placebo. Unlike in people, synbiotic administration did not decrease antibiotic‐associated diarrhea.

Oral Probiotics Alter Healthy Feline Respiratory Microbiota.

Probiotics have been advocated as a novel therapeutic approach to respiratory disease, but knowledge of how oral administration of probiotics influences the respiratory microbiota is needed. Using 16S rRNA amplicon sequencing of bacterial DNA our objective was to determine whether oral probiotics changed the composition of the upper and lower airway, rectal, and blood microbiota. We hypothesized that oral probiotics would modulate the respiratory microbiota in healthy cats, demonstrated by the detection and/or increased relative abundance of the probiotic bacterial species and altered composition of the microbial population in the respiratory tract. Six healthy young research cats had oropharyngeal (OP), bronchoalveolar lavage fluid (BALF), rectal, and blood samples collected at baseline and 4 weeks after receiving oral probiotics. 16S rRNA gene amplicon libraries were sequenced, and coverage, richness, and relative abundance of representative operational taxonomic units (OTUs) were determined. Hierarchical and principal component analyses (PCA) demonstrated relatedness of samples. Mean microbial richness significantly increased only in the upper and lower airways. The number of probiotic OTUs (out of 5 total) that significantly increased in relative abundance vs. baseline was 5 in OP, 3 in BAL and 2 in feces. Using hierarchical clustering, BALF and blood samples grouped together after probiotic administration, and PERMANOVA supported that these two sites underwent significant changes in microbial composition. PERMANOVA revealed that OP and rectal samples had microbial population compositions that did not significantly change. These findings were visualized via PCA, which revealed distinct microbiomes in each site; samples clustered more tightly at baseline and had more variation after probiotic administration. This is the first study describing the effect of oral probiotics on the respiratory microbiota via detection of probiotic species in the airways. Finding bacterial species present in the oral probiotics in the upper and lower airways provides pilot data suggesting that oral probiotics could serve as a tool to target dysbiosis occurring in inflammatory airway diseases such as feline asthma, a disease in which cats serve as an important comparative and translational model for humans.

Dynamic changes of the respiratory microbiota and its relationship to fecal and blood microbiota in healthy young cats.

Advances in the field of metagenomics using culture-independent methods of microbial identification have allowed characterization of rich and diverse communities of bacteria in the lungs of healthy humans, mice, dogs, sheep and pigs. These data challenge the long held belief that the lungs are sterile and microbial colonization is synonymous with pathology. Studies in humans and animals demonstrate differences in the composition of airway microbiota in health versus disease suggesting respiratory dysbiosis occurs. Using 16S rRNA amplicon sequencing of DNA extracted from rectal and oropharyngeal (OP) swabs, bronchoalveolar lavage fluid (BALF), and blood, our objective was to characterize the fecal, OP, blood, and lower airway microbiota over time in healthy cats. This work in healthy cats, a species in which a respiratory microbiota has not yet been characterized, sets the stage for future studies in feline asthma in which cats serve as a comparative and translational model for humans. Fecal, OP and BALF samples were collected from six healthy research cats at day 0, week 2, and week 10; blood was collected at week 10. DNA was extracted, amplified via PCR, and sequenced using the Illumina MiSeq platform. Representative operational taxonomic units (OTUs) were identified and microbial richness and diversity were assessed. Principal component analysis (PCA) was used to visualize relatedness of samples and PERMANOVA was used to test for significant differences in microbial community composition. Fecal and OP swabs provided abundant DNA yielding a mean±SEM of 65,653±6,145 and 20,6323±4,360 sequences per sample, respectively while BALF and blood samples had lower coverage (1,489±430 and 269±18 sequences per sample, respectively). Oropharyngeal and fecal swabs were significantly richer than BALF (mean number OTUs 93, 88 and 36, respectively; p < 0.001) with no significant difference (p = 0.180) in richness between time points. PCA revealed site-specific microbial communities in the feces, and upper and lower airways. In comparison, blood had an apparent compositional similarity with BALF with regard to a few dominant taxa, but shared more OTUs with feces. Samples clustered more by time than by individual, with OP swabs having subjectively greater variation than other samples. In summary, healthy cats have a rich and distinct lower airway microbiome with dynamic bacterial populations. The microbiome is likely to be altered by factors such as age, environmental influences, and disease states. Further data are necessary to determine how the distinct feline microbiomes from the upper and lower airways, feces and blood are established and evolve. These data are relevant for comparisons between healthy cats and cats with respiratory disease.

Dosing obese cats based on body weight spuriously affects some measures of glucose tolerance

The primary objective was to investigate whether dosing glucose by body weight results in spurious effects on measures of glucose tolerance in obese cats because volume of distribution does not increase linearly with body weight. Healthy research cats (n = 16; 6 castrated males, 10 spayed females) were used. A retrospective study was performed using glucose concentration data from glucose tolerance and insulin sensitivity tests before and after cats were fed ad libitum for 9 to 12 mo to promote weight gain. The higher dose of glucose (0.5 vs 0.3 g/kg body weight) in the glucose tolerance tests increased 2-min glucose concentrations (P < 0.001), and there was a positive correlation between 2-min and 2-h glucose (r = 0.65, P = 0.006). Two-min (P = 0.016 and 0.019, respectively), and 2-h (P = 0.057 and 0.003, respectively) glucose concentrations, and glucose half-life (T1/2; P = 0.034 and <0.001 respectively) were positively associated with body weight and body condition score. Glucose dose should be decreased by 0.05 g for every kg above ideal body weight. Alternatively, for every unit of body condition score above 5 on a 9-point scale, observed 2-h glucose concentration should be adjusted down by 0.1 mmol/L. Dosing glucose based on body weight spuriously increases glucose concentrations at 2 h in obese cats and could lead to cats being incorrectly classified as having impaired glucose tolerance. This has important implications for clinical studies assessing the effect of interventions on glucose tolerance when lean and obese cats are compared.

Evidence of Anaplasma phagocytophilum and Borrelia burgdorferi infection in cats after exposure to wild-caught adult Ixodes scapularis.

Cats are infected by Anaplasma phagocytophilum and Borrelia burgdorferi when exposed to infected Ixodes scapularis (black-legged ticks). The purpose of our study was to allow wild-caught I. scapularis to feed on healthy research cats (n = 4) and temporally evaluate for A. phagocytophilum DNA in blood by a polymerase chain reaction (PCR) assay as well as for antibody responses to the B. burgdorferi C6 peptide, to the A. phagocytophilum P44 peptide, and to a novel A. phagocytophilum peptide (P44-4). Prior to I. scapularis infestation, all cats were negative for antibodies against both organisms based on a kit optimized for dog serum, and negative for A. phagocytophilum DNA in blood using a conventional PCR assay. Using the pre-infestation samples, an enzyme-linked immunosorbent assay for detecting antibodies against the P44-4 peptide was optimized. Cats were infested with wild-caught I. scapularis for 7 days. Genomic DNA of A. phagocytophilum was amplified from the blood before antibodies were detected in all 4 cats. Antibodies against the C6 peptide, P44 peptide, and P44-4 peptide were detected in the sera of all 4 cats. Antibodies against P44-4 were detected prior to those against P44 in 3 out of 4 cats. The results suggest that a PCR assay should be considered in acutely ill cats with suspected anaplasmosis that are seronegative.

Pharmacokinetics of tacrolimus after multidose oral administration and efficacy in the prevention of allograft rejection in cats with renal transplants

To describe pharmacokinetics of multi-dose oral administration of tacrolimus in healthy cats and evaluate the efficacy of tacrolimus in the prevention of allograft rejection in cats with renal transplants. 6 healthy research cats. Cats received tacrolimus (0.375 mg/kg, PO, q 12 h) for 14 days. Blood tacrolimus concentrations were measured by a high performance liquid chromatography-mass spectrometry assay. Each cat received an immunogenically mismatched renal allograft and native kidney nephrectomy. Tacrolimus dosage was modified to maintain a target blood concentration of 5 to 10 ng/mL. Cats were euthanatized if plasma creatinine concentration exceeded 7 mg/dL, body weight loss exceeded 20%, or on day 50 after surgery. Kaplan-Meier survival curves were plotted for 6 cats treated with tacrolimus and for 8 cats with renal transplants that did not receive immunosuppressive treatment. Mean (+/- SD) values of elimination half-life, time to maximum concentration, maximum blood concentration, and area under the concentration versus time curve from the last dose of tacrolimus to 12 hours later were 20.5 +/- 9.8 hours, 0.77 +/- 0.37 hours, 27.5 +/- 31.8 ng/mL, and 161 +/- 168 hours x ng/mL, respectively. Tacrolimus treated cats survived longer (median, 44 days; range, 24 to 52 days) than untreated cats (median, 23 days; range, 8 to 34 days). On histologic evaluation, 3 cats had evidence of acute-active rejection, 1 cat had necrotizing vasculitis, and 2 cats euthanatized at study termination had normal appearing allografts. Tacrolimus may be an effective immunosuppressive agent for renal transplantation in cats.