Induction of diabetes by Tacrolimus in a phenotypic model of obesity and metabolic syndrome.

Introduction: The pathogenesis of Post-Transplant Diabetes Mellitus (PTDM) is complex and multifactorial and it resembles that of Type-2 Diabetes Mellitus (T2DM). One risk factor specific to PTDM differentiates both entities: the use of immunosuppressive therapy. Specifically, Tacrolimus interacts with obesity and insulin resistance (IR) in accelerating the onset of PTDM. In a genotypic model of IR, the obese Zucker rats, Tacrolimus is highly diabetogenic by promoting the same changes in beta-cell already modified by IR. Nevertheless, genotypic animal models have their limitations and may not resemble the real pathophysiology of diabetes. In this study, we have evaluated the interaction between beta-cell damage and Tacrolimus in a non-genotypic animal model of obesity and metabolic syndrome. Methods: Sprague Dawley rats were fed a high-fat enriched diet during 45 days to induce obesity and metabolic dysregulation. On top of this established obesity, the administration of Tacrolimus (1mg/kg/day) during 15 days induced severe hyperglycaemia and changes in morphological and structural characteristics of the pancreas. Results: Obese animals administered with Tacrolimus showed increased size of islets of Langerhans and reduced beta-cell proliferation without changes in apoptosis. There were also changes in beta-cell nuclear factors such as a decrease in nuclear expression of MafA and a nuclear overexpression of FoxO1A, PDX-1 and NeuroD1. These animals also showed increased levels of pancreatic insulin and glucagon. Discussion: This model could be evidence of the relationship between the T2DM and PTDM physiopathology and, eventually, the model may be instrumental to study the pathogenesis of T2DM.

Biological Activity of 6,7-Dehydroxyroyleanone and Derivatives Obtained from Plectranthus aliciae (Codd) A.J.Paton.

The Plectranthus genus (Lamiaceae) is known to be rich in abietane diterpenes. The bioactive 6,7-dehydroxyroyleanone (DHR, 1) was previously isolated from Plectranthus madagascariensis var. madagascariensis and var. aliciae. This study aimed to explore the occurrence of DHR, 1, in P. aliciae and the potential bioactivities of new semisynthetic derivatives from DHR, 1. Several extraction methods were evaluated, and the hydrodistillation, using a Clevenger apparatus, afforded the highest yield (77.8 mg/g of 1 in the essential oil). Three new acyl derivatives (2-4) were successfully prepared from 1 (yields of 86-95%). Compounds 1-4 showed antioxidant activity, antibacterial effects, potent cytotoxic activity against several cell lines, and enhanced anti-inflammatory activity that surpassed dexamethasone (positive control). These findings encourage further exploration of derivatives 2-4 for potential mechanisms of antitumoral, antioxidant, and anti-inflammatory capabilities, studying both safety and efficacy.

Drastic decline in vasoactive intestinal peptide expression in the suprachiasmatic nucleus in obese mice on a long-term high-fat diet.

The suprachiasmatic nucleus (SCN) is the main region for the regulation of circadian rhythms. Although the SCN contains a heterogeneous neurochemical phenotype with a wide variety of neuropeptides, a key role has been suggested for the vasoactive intestinal neuropeptide (VIP) as a modulator circadian, reproductive, and seasonal rhythms. VIP is a 28-amino acid polypeptide hormone that belongs to the secretin-glucagon peptide superfamily and shares 68 % homology with the pituitary adenylate cyclase-activating polypeptide (PACAP). VIP acts as an endogenous appetite inhibitor in the central nervous system, where it participates in the control of appetite and energy homeostasis. In recent years, significant efforts have been made to better understand the role of VIP in the regulation of appetite/satiety and energy balance. This study aimed to elucidate the long-term effect of an obesogenic diet on the distribution and expression pattern of VIP in the SCN and nucleus accumbens (NAc) of C57BL/6 mice. A total of 15 female C57BL/6J mice were used in this study. Female mice were fed ad libitum with water and, either a standard diet (SD) or a high-fat diet (HFD) to induce obesity. There were 7 female mice on the SD and 8 on the HFD. The duration of the experiment was 365 days. The morphological study was performed using immunohistochemistry and double immunofluorescence techniques to study the neurochemical profile of VIP neurons of the SCN of C57BL/6 mice. Our data show that HFD-fed mice gained weight and showed reduced VIP expression in neurons of the SCN and also in fibres located in the NAc. Moreover, we observed a loss of neuropeptide Y (NPY) expression in fibres surrounding the SCN. Our findings on VIP may contribute to the understanding of the pathophysiological mechanisms underlying obesity in regions associated with uncontrolled intake of high-fat foods and the reward system, thus facilitating the identification of novel therapeutic targets.

The Role of Gender Differences and Menopause in Obesity-Related Renal Disease, Renal Inflammation and Lipotoxicity.

The pathogenesis of obesity-related-renal disease is unknown. Menopause can promote renal disease in obese women, but this interaction is unclear. In a previous study, we observed that obese male and female mice developed albuminuria, hyperfiltration, and glomerulomegaly, and these changes were more severe in those obese ovariectomized females. In this study, we also evaluated renal inflammation and lipotoxicity in that animal model. For six months, 43 males and 36 females C57BL6/J mice were randomized to standard diet (SD) or high fat diet (HFD). A group of female animals on SD or HFD was ovariectomized to simulate menopause. We evaluated cytokines: NF-κß p65, IL-1ß, MCP-1, TNF-α, total lipid content, lipid classes, and fatty acid profile in total lipid and individual lipid classes in renal tissue and urine. We found that obese males and females showed higher NF-kß p-65, TNF-α and MCP-1 in renal tissue, and obese females ovariectomized had higher IL-1ß and TNF-α compared with not-ovariectomized. Also, obese animals showed lower proinflammatory and higher anti-inflammatory fatty acids in kidney total lipids, while obese females ovariectomized had a more exacerbated pattern. In brief, obesity induces inflammation and an unbalanced lipidic profile in renal tissue. This pattern seems to be enhanced in obesity after menopause.

Measured GFR in murine animal models: review on methods, techniques, and procedures.

Chronic kidney disease (CKD) is one of the most common chronic diseases worldwide, with increasing rates of morbidity and mortality. Thus, early detection is essential to prevent severe adverse events and the progression of kidney disease to an end stage. Glomerular filtration rate (GFR) is the most appropriate index to evaluate renal function in both clinical practice and basic medical research. Several animal models have been developed to understand renal disease induction and progression. Specifically, murine models are useful to study the pathogenesis of renal damage, so a reliable determination of GFR is essential to evaluate the progression of CKD. However, as in clinical practise, the estimation of GFR in murine by levels of serum/urine creatinine or cystatin-C could not be accurate and needed other more reliable methods. As an alternative, the measurement of GFR by the clearance of exogenous markers like inulin, sinistrin, 51Cr-EDTA, 99mTc-DTPA, 125I-iothalamate, or iohexol could be performed. Nevertheless, both approaches-estimation or measurement of GFR-have their limitations and a standard method for the GFR determination has not been defined. Altogether, in this review, we aim to give an overview of the current methods for GFR assessment in murine models, describing each methodology and focusing on their advantages and limitations.

Preliminary Biological Activity Screening of Plectranthus spp. Extracts for the Search of Anticancer Lead Molecules.

Plectranthus species (Lamiaceae) have been employed in traditional medicine and this is now validated by the presence of bioactive abietane-type diterpenoids. Herein, sixteen Plectranthus acetonic extracts were prepared by ultrasound-assisted extraction and their biological activity was screened. The antimicrobial activity of each extract was screened against yeasts, and Gram-positive and Gram-negative bacteria. The P. hadiensis and P. mutabilis extracts possessed significant activity against Staphylococcus aureus and Candida albicans (microdilution method). Moreover, all extracts showed antioxidant activity using the DPPH method, with P. hadiensis and P. mutabilis extracts having the highest scavenging activities. Selected by the Artemia salina model, P. hadiensis and P.ciliatus possessed low micromolar anti-proliferative activities in human colon, breast, and lung cancer cell lines. Furthermore, the most bioactive extract of P. hadiensis leaves and the known abietane diterpene, 7α-acetoxy-6ß-hydroxyroyleanone isolated from this plant, were tested against the aggressive type triple negative breast cancer (MDA-MB-231S). P. hadiensis extract reduced the viability of MDA-MB-231S cancer cell line cells, showing an IC50 value of 25.6 µg/mL. The IC50 value of 7α-acetoxy-6ß-hydroxyroyleanone was 5.5 µM (2.15 µg/mL), suggesting that this lead molecule is a potential starting tool for the development of anti-cancer drugs.