The relation between autophagy modulation by intermittent fasting and aquaporin 2 expression in experimentally induced diabetic nephropathy in albino rat

Polyuria is an early sign of diabetic nephropathy (DN) that produces dehydration in diabetic patients. This could be caused by alteration of renal aquaporin 2 (AQP2) expression. This study aimed to describe the relation between autophagy modulation via intermittent fasting (IF) and renal AQP2 expression and polyuria in case of DN. We divided the rats into control, DN and IF groups. After 2 and 4 weeks of diabetes induction, blood glucose (BG), serum creatinine (Scr), urine volume, and 24 hours urine protein (UP) were examined. Diabetic nephropathy histopathological index (DNHI) was calculated to evaluate histopathological changes. Immunohistochemistry and real-time PCR were performed to measure the levels of AQP2 and the autophagy marker; LC3 in kidney tissue. DNHI was correlated to the PCR and immunoexpression of AQP2 and LC3. Intermittent fasting significantly decreased the BG, Scr, urine volume, 24 hours UP, and DNHI as compared diabetes. Diabetes significantly elevated the immunoreactivity and mRNA expression levels of AQP2 and LC3 as compared to the control. However, the IF decreased AQP2 and stimulated autophagy in cyclic fashion. Our data revealed significant positive correlations between AQP2 and LC3 at the level of immunoexpression and mRNA at 2nd weeks. Taken together, these data showed that autophagy stimulation didn't regulate AQP2 expression in case of diabetic nephropathy, however IF decreased polyuria through improvement of glycemic state.

Toxicological Evaluation of a Probiotic-Based Delivery System for P8 Protein as an Anti-Colorectal Cancer Drug

Purpose

This study aimed to toxicological evaluate a probiotics-based delivery system for p8 protein as an anti-colorectal cancer drug.

Introduction

Lactic acid bacteria (LAB) have been widely ingested for many years and are regarded as very safe. Recently, a Pediococcus pentosaceus SL4 (PP) strain that secretes the probiotic-derived anti-cancer protein P8 (PP-P8) has been developed as an anti-colorectal cancer (CRC) biologic by Cell Biotech. We initially identified a Lactobacillus rhamnosus (LR)-derived anti-cancer protein, P8, that suppresses CRC growth. We also showed that P8 penetrates specifically into CRC cells (DLD-1 cells) through endocytosis. We then confirmed the efficacy of PP-P8, showing that oral administration of this agent significantly decreased tumor mass (~42%) relative to controls in a mouse CRC xenograft model. In terms of molecular mechanism, PP-P8 induces cell-cycle arrest in G₂ phase through down-regulation of Cyclin B1 and Cdk1. In this study, we performed in vivo toxicology profiling to obtain evidence that PP-P8 is safe, with the goal of receiving approval for an investigational new drug application (IND).

Methods

Based on gene therapy guidelines of the Ministry of Food and Drug Safety (MFDS) of Korea, the potential undesirable effects of PP-P8 had to be investigated in intact small rodent or marmoset models prior to first-in-human (FIH) administration. The estimated doses of PP-P8 for FIH are 1.0×10¹⁰ – 1.0×10¹¹ CFU/person (60 kg). Therefore, to perform toxicological investigations in non-clinical animal models, we orally administered PP-P8 at doses of 3.375 × 10¹¹, 6.75 × 10¹¹, and 13.5×10¹¹ CFU/kg/day; thus the maximum dose was 800–8000-fold higher than the estimated dose for FIH.

Results

In our animal models, we observed no adverse effects of PP-P8 on clinicopathologic findings, relative organ weight, or tissue pathology. In addition, we observed no inflammation or ulceration during pathological necropsy.

Conclusion

These non-clinical toxicology studies could be used to furnish valuable data for the safety certification of PP-P8.

Research Relevant Conditions and Pathology in Nonhuman Primates

Biomedical research involving animal models continues to provide important insights into disease pathogenesis and treatment of diseases that impact human health. In particular, nonhuman primates (NHPs) have been used extensively in translational research due to their phylogenetic proximity to humans and similarities to disease pathogenesis and treatment responses as assessed in clinical trials. Microscopic changes in tissues remain a significant endpoint in studies involving these models. Spontaneous, expected (ie, incidental or background) histopathologic changes are commonly encountered and influenced by species, genetic variations, age, and geographical origin of animals, including exposure to infectious or parasitic agents. Often, the background findings confound study-related changes, because numbers of NHPs used in research are limited by animal welfare and other considerations. Moreover, background findings in NHPs can be exacerbated by experimental conditions such as treatment with xenobiotics (eg, infectious morphological changes related to immunosuppressive therapy). This review and summary of research-relevant conditions and pathology in rhesus and cynomolgus macaques, baboons, African green monkeys, common marmosets, tamarins, and squirrel and owl monkeys aims to improve the interpretation and validity of NHP studies.

Clinical Management of Gastrointestinal Disease in the Common Marmoset (Callithrix jacchus)

Gastrointestinal disease is a frequently encountered problem among captive common marmoset (Callithrix jacchus) colonies. Management can be challenging due to the number of etiologies responsible for gastrointestinal disease in this species, limitations on diagnostic capabilities, and lack of effective treatments. Understanding commonly described GI diseases in the captive marmoset can provide insight on the impact these diseases have on research studies and aid in the development of appropriate management strategies. A review of commonly encountered GI disease processes as well as routinely implicated causes of GI disease in the common marmoset are provided. Current strategies in clinical management of GI disease in the common marmoset, including approaches to colony health, diagnostic testing, and commonly employed treatments are discussed.

Marmoset as a Model to Study Kidney Changes Associated With Aging

We evaluated whether the marmoset, a nonhuman primate, can serve as a good model to study aging-related changes in the kidney by employing healthy young and aged marmosets of both sexes. Aging was associated with glomerulosclerosis, interstitial fibrosis, and arteriolosclerosis in both sexes; correspondingly, the content of matrix proteins was increased. Functionally, aging resulted in an increase in urinary albumin and protein excretion. There was a robust correlation between markers of fibrosis and functional changes. We explored signaling pathways as potential mechanistic events. Aging in males, but not in females, was associated with reduced renal cortical activity of AMP-activated protein kinase (AMPK) and a trend toward activation of mechanistic target of rapamycin complex 1 (mTORC1); upstream of AMPK and mTORC1, Akt and IGF-1 receptor were activated. In both sexes, aging promoted kidney activation of transforming growth factor β-1 signaling pathway. While the expression of cystathionine β-synthase (CBS), an enzyme involved hydrogen sulfide (H2S) synthesis, was reduced in both aged males and females, decreased H2S generation was seen in only males. Our studies show that the marmoset is a valid model to study kidney aging; some of the signaling pathways involved in renal senescence differ between male and female marmosets.

RETROSPECTIVE MORTALITY REVIEW OF SIX CALLITRICHID SPECIES HOUSED AT A SINGLE INSTITUTION (1990-2014)

Callitrichids are commonly exhibited species in zoological institutions. Retrospective mortality studies allow institutions to evaluate health trends in captive populations and have the potential to advance zoological medicine and husbandry practices. In this single institution, retrospective study, histopathologic records were reviewed for 166 callitrichids comprising six species. For all species and age-groups combined, trauma was the leading cause of death followed by enteritis and stillbirth. In adults and juveniles, the leading cause of death was enteritis, with neonates dying primarily from trauma. Neonatal mortality was high for most species, ranging from 12.5% to 60%, with most neonatal loss in Geoffroy's and pied tamarins. Twin births were commonly associated with neonatal mortality in most species. Intestinal adenocarcinoma was a common finding for adult Geoffroy's tamarin, and hemosiderosis was also identified in this species. Renal disease was a common finding in adult callitrichids and was the second most common cause of death in this age-group. Mortality in the juvenile period (>30 days-1 yr) was uncommon, comprising only 8.4% of the data set. Although capable of surviving into advanced age (>20 yr for one animal), the average age at death for all age classes was 3.84 yr and 9.31 yr for adults. This study contributes to the current knowledge regarding trends in callitrichid health and husbandry and can be used to investigate health trends in this group.

Distribution and Activity of Mitochondrial Proteins in Vascular and Avascular Retinas: Implications for Retinal Metabolism

Purpose

Understanding the energetics of retinal neurons and glia is crucial for developing therapies for diseases that feature deficits in nutrient or oxygen availability. Herein, we performed a detailed characterization of the distribution and activity of mitochondrial proteins in the vascularized retinas of rat and marmoset, and the avascular retinas of rabbit and guinea pig. Further, we delineated expression of ubiquitous mitochondrial creatine kinase (uMtCK).

Methods

Expression of eight mitochondrial proteins was investigated using Western blotting, single- and double-labeling immunohistochemistry. Activities of cytochrome c oxidase, succinate dehydrgogenase, and isocitrate dehydrogenase were determined by enzyme histochemistry using unfixed tissue sections.

Results

In vascularized retinas, immunoreactivities were characterized by strong, punctate labeling in the plexiform layers, photoreceptor inner segments, somas of various cell types, notably retinal ganglion cells (RGCs), and the basolateral surface of the retinal pigment epithelium. In avascular retinas, immunoreactivities featured intense labeling of inner segments, together with weak, but unambiguous, staining of both plexiform layers. RGCs were relatively enriched. In Müller cells of avascular retinas, mitochondria were restricted to scleral-end processes. For each species, enzyme activity assays yielded similar results to the protein distributions. Labeling for uMtCK in vascular and avascular retinas was fundamentally similar, being restricted to neuronal populations, most notably inner segments and RGCs. Of all of the mitochondrial proteins, uMtCK displayed the strongest labeling in avascular retinas. uMtCK was not detectable in Müller cells in any species.

Conclusions

The current findings advance our understanding of the metabolic similarities and differences between vascular and avascular retinas.

Cross-sectional comparison of health-span phenotypes in young versus geriatric marmosets

The development of the marmoset as a translational model for healthspan and lifespan studies relies on the characterization of health parameters in young and geriatric marmosets. This cross-sectional study examined health phenotypes in marmosets for five domains of interest for human health and aging: mobility, cognition, metabolism, homeostasis, and immune function. Geriatric marmosets were found to have significant executive function impairment when compared to young animals. While geriatric animals did not show gross abnormalities in mobility and measures of locomotion, their types of movement were altered from young animals. Geriatric marmosets had alterations in cardiac function, with significantly increased mean arterial pressures; metabolism, with significantly lower VO2 ; and suppressed immune function. Further, this study sought to characterize and describe histopathology for both young and geriatric healthy marmosets. Overall this study provides a characterization of health parameters for young and geriatric marmosets which will greatly enhance future aging and interventional testing in marmosets.

Metabolic Dysregulation in Hepacivirus Infection of Common Marmosets (Callithrix jacchus)

Chronic hepatitis C has been associated with metabolic syndrome that includes insulin resistance, hepatic steatosis and obesity. These metabolic aberrations are risk factors for disease severity and treatment outcome in infected patients. Experimental infection of marmosets with GBV-B serves as a tangible, small animal model for human HCV infection, and while virology and pathology are well described, a full investigation of clinical disease and the metabolic milieu is lacking. In this study six marmosets were infected intravenously with GBV-B and changes in hematologic, serum biochemical and plasma metabolic measures were investigated over the duration of infection. Infected animals exhibited signs of lymphocytopenia, but platelet and RBC counts were generally stable or even increased. Although most animals showed a transient decline in blood glucose, infection resulted in several fold increases in plasma insulin, glucagon and glucagon-like peptide 1 (GLP-1). All infected animals experienced transient weight loss within the first 28 days of infection, but also became hypertriglyceridemic and had up to 10-fold increases in adipocytokines such as resistin and plasminogen activator inhibitor 1 (PAI-1). In liver, moderate to severe cytoplasmic changes associated with steatotic changes was observed microscopically at 168 days post infection. Collectively, these results suggest that GBV-B infection is accompanied by hematologic, biochemical and metabolic abnormalities that could lead to obesity, diabetes, thrombosis and atherosclerosis, even after virus has been cleared. Our findings mirror those found in HCV patients, suggesting that metabolic syndrome could be conserved among hepaciviruses, and both mechanistic and interventional studies for treating HCV-induced metabolic complications could be evaluated in this animal model.

EVALUATION OF IN-HOUSE URINE DIPSTICK, REFERENCE LABORATORY URINALYSIS, AND URINE PROTEIN: CREATININE RATIO FROM A COLONY OF CALLIMICOS (CALLIMICO GOELDII)

This study evaluated results from an in-house (IH) laboratory dipstick, a reference laboratory (RL) urinalysis, and urine protein : creatinine (UPC) ratios from callimicos ( Callimico goeldii ). Urine was collected from 25 individuals comprising a single colony under professional care in North America and compared based on laboratory, sex, age class, and presence or absence of a normal urinalysis. Urine specific gravity and pH between laboratories were statistically different. Overall, 56% to 100% of animals had at least a trace amount of protein in their urine. In comparing normal and abnormal urinalyses, IH dipstick protein, RL dipstick protein, RL pH, quantitative protein measurement, and UPC ratios were all statistically different. Eleven animals (44%) had UPC ratios that were ≥0.5. Based on results of this study, UPC > 0.3 was found to be abnormal and supportive of renal compromise in callimicos. Higher protein concentrations on the IH dipstick, the quantitative protein concentration, and UPC ratio in the 1- to 4-yr-old age class were the only significant age-related differences. There was no association between any categorical variable (glucose, blood, bilirubin, ketones, urobilinogen) and abnormal urinalysis. There were no differences between sexes. Since renal disease is a major cause of morbidity and mortality in this species, the authors recommend including routine urinalyses and UPC ratios as part of preventive care programs for callimicos. These data provide the first published information on urinalysis and UPC ratios in callimicos and will serve as a helpful reference for interpreting results and evaluating patients with renal disease.