Low serum creatinine, a surrogate marker of muscle mass, correlates with insulin sensitivity in nonhuman primates.

OBJECTIVES: Decreased serum creatinine levels are associated with increased risk of type 2 diabetes (T2DM) in humans, however, its association with muscle mass and insulin sensitivity have not been studied in NHPs. METHODS: Retrospective data of 229 adult NHPs were studied for association of serum creatinine levels with muscle mass and onset of T2DM. RESULTS: Serum creatinine levels were positively correlated with lean muscle mass in nondiabetic (non-DM), male and female NHPs. Aged NHPs had significantly reduced lean muscle mass and corresponding creatinine levels compared to young age groups (p < .001). Creatinine was positively correlated with insulin sensitivity in nonDM male NHPs and significant decrease in creatinine was observed in T2DM (p < .001) compared to same age group nonDM NHPs. CONCLUSIONS: The pathophysiology of T2DM in NHPs is similar to humans, low creatinine further provides utility of surrogate biomarkers of lower muscle mass and risk factor for T2DM NHPs.

Iron deficiency, but not anemia, is identified in naturally occurring obesity and insulin resistance in male nonhuman primates.

OBJECTIVES: To understand the development of iron deficiency in obesity and its long-term impact on the profile of anemia in spontaneously obese nonhuman primates. METHODS: The study included 69 adult male nonhuman primates, (NHPs, Macaca mulatta, rhesus monkeys), ranging from normal to obese, and type 2 diabetes (T2D) as defined for humans. RESULTS: Iron deficiency was present in 31.9% and mild anemia in 13% of the rhesus monkey in the colony. Serum iron levels were significantly lower in obese (p < .01) and T2D (p < .01)) compared with normal NHP. Obese NHPs also had significantly higher hemoglobin (p < .05), and red blood cell count (p < .05) than normal weight NHPs, thus not related to anemia. CONCLUSIONS: Iron deficiency with increased hemoglobin and red blood cells was significantly associated with increased adiposity, insulin resistance, and diabetes. Iron deficiency does not cause and is not related to anemia in obese and T2D NHPs.

Altered expression of p63 isoforms and expansion of p63- and club cell secretory protein-positive epithelial cells in the lung as novel features of aging.

Aging is a key contributor for subclinical progression of late-onset lung diseases. Basal, club, and type II alveolar epithelial cells (AECs) are lung epithelial progenitors whose capacities of differentiation are extensively studied. The timely transition of these cells in response to environmental changes helps maintain the intricate organization of lung structure. However, it remains unclear how aging affects their behavior. This paper demonstrates that the protein expression profiles of a type II AEC marker, prosurfactant protein C (pro-SPC), and a basal cell marker, p63, are altered in the lungs of 14-mo-old versus 7- to 9-wk-old mice. Expression of NH2-terminal-truncated forms of p63 (ΔNp63), a basal cell marker, and claudin-10, a club cell marker, in cytoplasmic extracts of lungs of 14-mo-old mice was upregulated. In contrast, nuclear expression of full-length forms of p63 (TAp63) decreases with age. These alterations in protein expression profiles coincide with dramatic changes in lung functions including compliance. Whole tissue lysates of middle-aged versus aged rhesus monkey lungs display similar age-associated alterations in pro-SPC expression. An age-associated decrease of TAp63 in nuclear lysates was observed in aged monkey group. Moreover, the lungs of 14-mo-old versus 7- to 9-wk-old mice display a wider spreading of ΔNp63-positive CCSP-positive bronchiolar epithelial cells. This expansion did not involve upregulation of Ki67, a representative proliferation marker. Collectively, it is postulated that 1) this expansion is secondary to a transition of progenitor cells committed to club cells from ΔNp63-negative to ΔNp63-positive status, and 2) high levels of cytoplasmic ΔNp63 expression trigger club cell migration.

Does obesity cause type 2 diabetes mellitus (T2DM)? Or is it the opposite?

Obesity is believed to be a promoter of type 2 diabetes mellitus (T2DM). Reports indicate that severe obesity in childhood and adolescence increases the risk of T2DM in youth and young adults. T2DM, which is commonly asymptomatic, frequently is not recognized until random blood glucose is measured. Screening blood glucose levels measured in obese individuals are more effective for identifying undiagnosed persons, than screening the general population and therefore introduces a selection bias for discovery. The following commentary will indicate why these observations do not indicate that obesity is the cause of T2DM. Also, it will be shown that the insulin resistance of T2DM occurs primarily in the muscles of lean individuals predisposed to diabetes before they become obese. This insulin resistance is not secondary to, but instead, is the cause of the excessive fat accumulation associated with T2DM. Moreover, this early muscle insulin resistance is the etiology of the hyperlipidemia and excess fat accumulation characteristic of T2DM.

Ensuring due process in the IACUC and animal welfare setting: considerations in developing noncompliance policies and procedures for institutional animal care and use committees and institutional officials.

Every institution that is involved in research with animals is expected to have in place policies and procedures for the management of allegations of noncompliance with the Animal Welfare Act and the U.S. Public Health Service Policy on the Humane Care and Use of Laboratory Animals. We present here a model set of recommendations for institutional animal care and use committees and institutional officials to ensure appropriate consideration of allegations of noncompliance with federal Animal Welfare Act regulations that carry a significant risk or specific threat to animal welfare. This guidance has 3 overarching aims: 1) protecting the welfare of research animals; 2) according fair treatment and due process to an individual accused of noncompliance; and 3) ensuring compliance with federal regulations. Through this guidance, the present work seeks to advance the cause of scientific integrity, animal welfare, and the public trust while recognizing and supporting the critical importance of animal research for the betterment of the health of both humans and animals.-Hansen, B. C., Gografe, S., Pritt, S., Jen, K.-L. C., McWhirter, C. A., Barman, S. M., Comuzzie, A., Greene, M., McNulty, J. A., Michele, D. E., Moaddab, N., Nelson, R. J., Norris, K., Uray, K. D., Banks, R., Westlund, K. N., Yates, B. J., Silverman, J., Hansen, K. D., Redman, B. Ensuring due process in the IACUC and animal welfare setting: considerations in developing noncompliance policies and procedures for institutional animal care and use committees and institutional officials.

Xenograft of microencapsulated Sertoli cells restores glucose homeostasis in db/db mice with spontaneous diabetes mellitus.

BACKGROUND: Increased abdominal fat and chronic inflammation in the expanded adipose tissue of obesity contribute to the development of insulin resistance and type 2 diabetes mellitus (T2D). The emerging immunoregulatory and anti-inflammatory properties of Sertoli cells have prompted their application to experimental models of autoimmune/inflammatory disorders, including diabetes. The main goal of this work was to verify whether transplantation of microencapsulated prepubertal porcine Sertoli cells (MC-SC) in the subcutaneous abdominal fat depot of spontaneously diabetic and obese db/db mice (homozygous for the diabetes spontaneous mutation [Leprdb ]) would: (i) improve glucose homeostasis and (ii) modulate local and systemic immune response and adipokines profiles. METHODS: Porcine prepubertal Sertoli cells were isolated, according to previously established methods and enveloped in Barium alginate microcapsules by a mono air-jet device. MC-SC were then injected in the subcutaneous abdominal fat depot of db/db mice. RESULTS: We have preliminarily shown that graft of MC-SC restored glucose homeostasis, with normalization of glycated hemoglobin values with improvement of the intraperitoneal glucose tolerance test in 60% of the treated animals. These results were associated with consistent increase, in the adipose tissue, of uncoupling protein 1 expression, regulatory B cells, anti-inflammatory macrophages and a concomitant decrease of proinflammatory macrophages. Furthermore, the treated animals showed a reduction in inducible NOS and proinflammatory molecules and a significant increase in an anti-inflammatory cytokine such as IL-10 along with concomitant rise of circulating adiponectin levels. The anti-hyperglycemic graft effects also emerged from an increased expression of GLUT-4, in conjunction with downregulation of GLUT-2, in skeletal muscle and liver, respectively. CONCLUSIONS: Preliminarily, xenograft of MC-SC holds promises for an effective cell therapy approach for treatment of experimental T2D.

Holocene dynamics of the Florida Everglades with respect to climate, dustfall, and tropical storms.

Aeolian dust is rarely considered an important source for nutrients in large peatlands, which generally develop in moist regions far from the major centers of dust production. As a result, past studies assumed that the Everglades provides a classic example of an originally oligotrophic, P-limited wetland that was subsequently degraded by anthropogenic activities. However, a multiproxy sedimentary record indicates that changes in atmospheric circulation patterns produced an abrupt shift in the hydrology and dust deposition in the Everglades over the past 4,600 y. A wet climatic period with high loadings of aeolian dust prevailed before 2800 cal BP (calibrated years before present) when vegetation typical of a deep slough dominated the principal drainage outlet of the Everglades. This dust was apparently transported from distant source areas, such as the Sahara Desert, by tropical storms according to its elemental chemistry and mineralogy. A drier climatic regime with a steep decline in dustfall persisted after 2800 cal BP maintaining sawgrass vegetation at the coring site as tree islands developed nearby (and pine forests covered adjacent uplands). The marked decline in dustfall was related to corresponding declines in sedimentary phosphorus, organic nitrogen, and organic carbon, suggesting that a close relationship existed between dustfall, primary production, and possibly, vegetation patterning before the 20th century. The climatic change after 2800 cal BP was probably produced by a shift in the Bermuda High to the southeast, shunting tropical storms to the south of Florida into the Gulf of Mexico.

Amylase and lipase levels in the metabolic syndrome and type 2 diabetes: A longitudinal study in rhesus monkeys.

Latent associations between low serum amylase and reduced plasma insulin levels and increased adiposity have been described previously in a small study of asymptomatic middle-aged humans. In the present study, we sought to determine the nature of such changes during the longitudinal progression from metabolically normal to overt type 2 diabetes mellitus (T2DM) in nonhuman primates (NHPs), a disease that appears to be the same in both pathophysiology and underlying mechanisms as that which most commonly develops in middle-aged adult humans. Amylase and lipase levels were characterized in 157 unrelated adult rhesus monkeys (Macaca mulatta); 38% developed T2DM while under study. In all monkeys, multivariable linear regression analysis revealed that amylase could be negatively predicted by % body fat (ß -0.29; p = 0.002), age (ß -0.27; p = 0.005), and HbA1c (ß -0.18; p = 0.037). Amylase levels were positively predicted by lipase levels (ß = 0.19; p = -0.024) in all NHPs included in the study. Amylase was significantly lower in NHPs with metabolic syndrome (p < 0.001), prediabetes (PreDM) (p < 0.001), and T2DM (p < 0.001) compared to metabolically normal adult NHPs. Lipase increased in NHPs with PreDM (p = 0.005) and T2DM (p = 0.04) compared to normal NHPs. This is the first longitudinal study of any species, including humans, to show the dynamics of amylase and lipase during the metabolic progression from normal to metabolic syndrome, to PreDM and then to overt T2DM. The extraordinary similarity between humans and monkeys in T2DM, in pancreatic pathophysiology and in metabolic functions give these findings high translational value.

Plasma lipid profiling across species for the identification of optimal animal models of human dyslipidemia.

In an attempt to understand the applicability of various animal models to dyslipidemia in humans and to identify improved preclinical models for target discovery and validation for dyslipidemia, we measured comprehensive plasma lipid profiles in 24 models. These included five mouse strains, six other nonprimate species, and four nonhuman primate (NHP) species, and both healthy animals and animals with metabolic disorders. Dyslipidemic humans were assessed by the same measures. Plasma lipoprotein profiles, eight major plasma lipid fractions, and FA compositions within these lipid fractions were compared both qualitatively and quantitatively across the species. Given the importance of statins in decreasing plasma low-density lipoprotein cholesterol for treatment of dyslipidemia in humans, the responses of these measures to simvastatin treatment were also assessed for each species and compared with dyslipidemic humans. NHPs, followed by dog, were the models that demonstrated closest overall match to dyslipidemic humans. For the subset of the dyslipidemic population with high plasma triglyceride levels, the data also pointed to hamster and db/db mouse as representative models for practical use in target validation. Most traditional models, including rabbit, Zucker diabetic fatty rat, and the majority of mouse models, did not demonstrate overall similarity to dyslipidemic humans in this study.

Metabolomics reveals attenuation of the SLC6A20 kidney transporter in nonhuman primate and mouse models of type 2 diabetes mellitus.

To enhance understanding of the metabolic indicators of type 2 diabetes mellitus (T2DM) disease pathogenesis and progression, the urinary metabolomes of well characterized rhesus macaques (normal or spontaneously and naturally diabetic) were examined. High-resolution ultra-performance liquid chromatography coupled with the accurate mass determination of time-of-flight mass spectrometry was used to analyze spot urine samples from normal (n = 10) and T2DM (n = 11) male monkeys. The machine-learning algorithm random forests classified urine samples as either from normal or T2DM monkeys. The metabolites important for developing the classifier were further examined for their biological significance. Random forests models had a misclassification error of less than 5%. Metabolites were identified based on accurate masses (<10 ppm) and confirmed by tandem mass spectrometry of authentic compounds. Urinary compounds significantly increased (p < 0.05) in the T2DM when compared with the normal group included glycine betaine (9-fold), citric acid (2.8-fold), kynurenic acid (1.8-fold), glucose (68-fold), and pipecolic acid (6.5-fold). When compared with the conventional definition of T2DM, the metabolites were also useful in defining the T2DM condition, and the urinary elevations in glycine betaine and pipecolic acid (as well as proline) indicated defective re-absorption in the kidney proximal tubules by SLC6A20, a Na(+)-dependent transporter. The mRNA levels of SLC6A20 were significantly reduced in the kidneys of monkeys with T2DM. These observations were validated in the db/db mouse model of T2DM. This study provides convincing evidence of the power of metabolomics for identifying functional changes at many levels in the omics pipeline.

Vasomotion becomes less random as diabetes progresses in monkeys.

Please cite this paper as: Tigno, Hansen, Nawang, Shamekh, and Albano (2011). Vasomotion Becomes Less Random as Diabetes Progresses in Monkeys. Microcirculation 18(6), 429-439. OBJECTIVE: Changes in vasomotion may precede other global indices of autonomic dysfunction that track the onset and progression of diabetes. Recently, we showed that baseline spectral properties of vasomotion can discriminate among N, PreDM, and T2DM nonhuman primates. In this study, our aims were to: (i) determine the time dependence and complexity of the spectral properties of vasomotion in three metabolic groups of monkeys; (ii) examine the effects of heat-provoked vasodilatation on the power spectrum; and (iii) compare the effects of exogenous insulin on the vasomotion. MATERIALS AND METHODS: Laser Doppler flow rates were measured from the foot in 9 N, 11 PreDM, and 7 T2DM monkeys. Baseline flow was measured at 34°C, and under heat stimulation at 44°C. Euglycemic-hyperinsulinemic clamps were performed to produce acute hyperinsulinemia. The Lempel-Ziv complexity, prediction error, and covariance complexity of five-dimensional embeddings were calculated as measures of randomness. RESULTS AND CONCLUSIONS: With progression of diabetes, measures of randomness of the vasomotion progressively decreased, suggesting a progressive loss of the homeostatic capacity of the peripheral circulation to respond to environmental changes. Power spectral density among T2DM animals resided mostly in the 0- to 1.45-Hz range, which excluded the cardiac component, suggesting that with progression of the disease, regulation of flow shifts toward local rather than central (autonomic) mechanisms. Heating increased all components of the spectral power in all groups. In N, insulin increased the vasomotion contributed by endothelial, neurogenic, vascular myogenic, and respiratory processes, but diminished that due to heart rate. In contrast, in T2DM, insulin failed to stimulate the vascular myogenic and respiratory activities, but increased the neural/endothelial and heart rate components. Interestingly, acute hyperinsulinemia resulted in no significant vasomotion changes in the chronically hyperinsulinemic PreDM, suggesting yet another form of "insulin resistance" during this stage of the disease.

Effects of aleglitazar, a balanced dual peroxisome proliferator-activated receptor α/γ agonist on glycemic and lipid parameters in a primate model of the metabolic syndrome.

BACKGROUND: Glycemic control and management of dyslipidemia to reduce cardiovascular risk are major therapeutic goals in individuals with type 2 diabetes mellitus (T2DM). This study was performed to evaluate the effects of aleglitazar, a balanced dual peroxisome proliferator-activated receptor α/γ (PPARα/γ) agonist, on both lipid and glycemic parameters in obese, hypertriglyceridemic, insulin-resistant rhesus monkeys. METHODS: A 135-day efficacy study was performed in six rhesus monkeys. After a 28-day baseline assessment (vehicle only), monkeys received oral aleglitazar 0.03 mg/kg per day for 42 days, followed by a 63-day washout period. Plasma levels of markers of glycemic and lipid regulation were measured at baseline, at the end of the dosing period, and at the end of the washout period. RESULTS: Compared with baseline values, aleglitazar 0.03 mg/kg per day reduced triglyceride levels by an average of 89% (328 to 36 mg/dL; P = 0.0035 when normalized for baseline levels) and increased high-density lipoprotein cholesterol levels by 125% (46 to 102 mg/dL; P = 0.0007). Furthermore, aleglitazar reduced low-density lipoprotein cholesterol levels (41%) and increased levels of apolipoprotein A-I (17%) and A-II (17%). Aleglitazar also improved insulin sensitivity by 60% (P = 0.001). Mean body weight was reduced by 5.9% from baseline values with aleglitazar at this dose (P = 0.043). CONCLUSIONS: Aleglitazar, a dual PPARα/γ agonist, has beneficial effects on both lipid and glucose parameters and may have a therapeutic role in modifying cardiovascular risk factors and improving glycemic control in patients with T2DM.

Glomerulopathy in spontaneously obese rhesus monkeys with type 2 diabetes: a stereological study.

BACKGROUND: Animal models could provide insights into the diabetic nephropathy pathogenesis; however, available rodent models do not mirror the heterogeneity of lesions in type 2 diabetic patients, and do not progress to end-stage renal disease. Previous studies showed that spontaneously obese type 2 diabetic rhesus monkeys develop many of the features of human diabetic glomerulopathy, and may progress to end-stage renal disease. Here, in order to further characterize diabetic glomerulopathy in this model, we used electron microscopic stereology. METHODS: Renal biopsies from 17 diabetic, 17 pre-diabetic/metabolic syndrome and 11 non-diabetic monkeys were studied. Fractional volumes of mesangium [Vv(Mes/glom)], mesangial matrix [Vv(MM/glom)] and mesangial cells [Vv(MC/glom)], glomerular basement membrane width and peripheral glomerular basement membrane surface density per glomerulus [Sv(PGBM/glom)] were estimated. Glomerular filtration and albumin excretion rates were measured in a limited number of animals. Glomerular structural and biochemical/metabolic data were compared among the groups. RESULTS: Compared to non-diabetic monkeys, diabetic rhesus monkeys showed classic diabetic nephropathy changes, including glomerular basement membrane thickening (p = 0.001), increased fractional volumes of mesangium (p = 0.02), and reduced peripheral glomerular basement membrane surface density per glomerulus (p = 0.03) compared to non-diabetic monkeys. Increased fractional volumes of mesangium was primarily due to increased mesangial matrix (p = 0.03). Glomerular structural parameter inter-relationships in diabetic monkeys mirrored those of human diabetic glomerulopathy. Albumin excretion rate was greater (p = 0.03) in diabetic vs. non-diabetic monkeys. There was trend for a positive correlation between albumin excretion rate and fractional volumes of mesangium. CONCLUSIONS: This rhesus primate model shares many features of human diabetic glomerulopathy. Mesangial expansion in this model, similar to human diabetic nephropathy and different from available rodent models of the disease, is primarily due to increased mesangial matrix.

The Obesity Society is turning 40: A history of the early years.

The North American Association for the Study of Obesity (NAASO), the precursor of The Obesity Society (TOS), was founded in 1981 and turns 40 years old in 2021. The Society was organized by George Bray along with John Brunzell, C. Wayne Callaway, M.R.C. Greenwood, and Judith Stern. It held its foundational meeting with a theme of "Types of Obesity: Animal Models and Clinical Applications" at Vassar College in the fall of 1982 along with symposia and an NIH workshop titled "Methods of Characterizing Human Obesity." At a follow-up meeting during the Fourth International Congress on Obesity, Barbara Hansen was elected President, Judith Stern Secretary, and Anne Sullivan Treasurer. Incorporation of NAASO occurred in 1984.

Roles of hepatic atypical protein kinase C hyperactivity and hyperinsulinemia in insulin-resistant forms of obesity and type 2 diabetes mellitus.

Diet-induced obesity, the metabolic syndrome, type 2 diabetes (DIO/MetS/T2DM), and their adverse sequelae have reached pandemic levels. In mice, DIO/MetS/T2DM initiation involves diet-dependent increases in lipids that activate hepatic atypical PKC (aPKC) and thereby increase lipogenic enzymes and proinflammatory cytokines. These or other hepatic aberrations, via adverse liver-to-muscle cross talk, rapidly impair postreceptor insulin signaling to glucose transport in muscle. The ensuing hyperinsulinemia further activates hepatic aPKC, which first blocks the ability of Akt to suppress gluconeogenic enzyme expression, and later impairs Akt activation, further increasing hepatic glucose production. Recent findings suggest that hepatic aPKC also increases a proteolytic enzyme that degrades insulin receptors. Fortunately, all hepatic aberrations and muscle impairments are prevented/reversed by inhibition or deficiency of hepatic aPKC. But, in the absence of treatment, hyperinsulinemia induces adverse events, some by using "spare receptors" to bypass receptor defects. Thus, in brain, hyperinsulinemia increases Aß-plaque precursors and Alzheimer risk; in kidney, hyperinsulinemia activates the renin-angiotensin-adrenal axis, thus increasing vasoconstriction, sodium retention, and cardiovascular risk; and in liver, hyperinsulinemia increases lipogenesis, obesity, hepatosteatosis, hyperlipidemia, and cardiovascular risk. In summary, increases in hepatic aPKC are critically required for development of DIO/MetS/T2DM and its adverse sequelae, and therapeutic approaches that limit hepatic aPKC may be particularly effective.

Control of ß-Site Amyloid Precursor Protein-Cleaving Enzyme-1 Expression by Protein Kinase C-λ/ι and Nuclear Factor κ-B.

Βackground: ß-Amyloid precursor protein-cleaving enzyme-1 (BACE1) initiates the production of Aß-peptides that form Aß-plaque in Alzheimer's disease. METHODS: Reportedly, acute insulin treatment in normal mice, and hyperinsulinemia in high-fat-fed (HFF) obese/diabetic mice, increase BACE1 activity and levels of Aß-peptides and phospho- -thr-231-tau in the brain; moreover, these effects are blocked by PKC-λ/ι inhibitors. However, as chemical inhibitors may affect unsuspected targets, we presently used knockout methodology to further examine PKC-λ/ι requirements. We found that total-body heterozygous PKC-λ knockout reduced acute stimulatory effects of insulin and chronic effects of hyperinsulinemia in HFF/obese/diabetic mice, on brain PKC-λ activity and production of Aß1-40/42 and phospho-thr-231-tau. This protection in HFF mice may reflect that hepatic PKC-λ haploinsufficiency prevents the development of glucose intolerance and hyperinsulinemia. RESULTS: On the other hand, heterozygous knockout of PKC-λ markedly reduced brain levels of BACE1 protein and mRNA, and this may reflect diminished activation of nuclear factor kappa-B (NFκB), which is activated by PKC-λ and increases BACE1 and proinflammatory cytokine transcription. Accordingly, whereas intravenous administration of aPKC inhibitor diminished aPKC activity and BACE1 levels by 50% in the brain and 90% in the liver, nasally-administered inhibitor reduced aPKC activity and BACE1 mRNA and protein levels by 50-70% in the brain while sparing the liver. Additionally, 24-hour insulin treatment in cultured human-derived neurons increased NFκB activity and BACE1 levels, and these effects were blocked by various PKC-λ/ι inhibitors. CONCLUSION: PKC-λ/ι controls NFκB activity and BACE1 expression; PKC-λ/ι inhibitors may be used nasally to target brain PKC-λ/ι or systemically to block both liver and brain PKC-λ/ι, to regulate NFκB-dependent BACE1 and proinflammatory cytokine expression.

Role of Sertoli Cell Proteins in Immunomodulation.

BACKGROUND: Sertoli cell, over the past 30 years, have been elevated from simple mechanical elements to the rank of a "sentinel" in spermatogenesis. By delivering potent immunomodulatory and trophic proteins, Sertoli cells are unique cell type with a pivotal role in maintaining testis immune privilege and the immune-protection of the antigenic germ cells. CONCLUSIONS: The findings from SC transplantation studies utilizing experimental animal models of disease, demonstrate the presence of the same immuno-modulation properties and mechanisms at tissue and organ sites far from testis. The complex pathways that generate and maintain the immune tolerance involve the production of several immunomodulatory or immune-related proteins such as cytokines, chemokines, growth factors, mediators of the inflammation, complement inhibitors or adhesion molecules. A better definition and understanding of these Sertoli cell proteins and the mechanisms of immunoprotection should help to elucidate their role in the spermatogenic process. The demonstration of their capabilities in transplantation experiments suggests that Sertoli cells may be good candidates in cell therapy for a number of cell-mediated chronic diseases.

Atypical PKC, PKCλ/ι, activates ß-secretase and increases Aß1-40/42 and phospho-tau in mouse brain and isolated neuronal cells, and may link hyperinsulinemia and other aPKC activators to development of pathological and memory abnormalities in Alzheimer's disease.

Hyperinsulinemia activates brain Akt and PKC-λ/ι and increases Aß1-40/42 and phospho-tau in insulin-resistant animals. Here, we examined underlying mechanisms in mice, neuronal cells, and mouse hippocampal slices. Like Aß1-40/42, ß-secretase activity was increased in insulin-resistant mice and monkeys. In insulin-resistant mice, inhibition of hepatic PKC-λ/ι sufficient to correct hepatic abnormalities and hyperinsulinemia simultaneously reversed increases in Akt, atypical protein kinase C (aPKC), ß-secretase, and Aß1-40/42, and restored acute Akt activation. However, 2 aPKC inhibitors additionally blocked insulin's ability to activate brain PKC-λ/ι and thereby increase ß-secretase and Aß1-40/42. Furthermore, direct blockade of brain aPKC simultaneously corrected an impairment in novel object recognition in high-fat-fed insulin-resistant mice. In neuronal cells and/or mouse hippocampal slices, PKC-ι/λ activation by insulin, metformin, or expression of constitutive PKC-ι provoked increases in ß-secretase, Aß1-40/42, and phospho-thr-231-tau that were blocked by various PKC-λ/ι inhibitors, but not by an Akt inhibitor. PKC-λ/ι provokes increases in brain ß-secretase, Aß1-40/42, and phospho-thr-231-tau. Excessive signaling via PKC-λ/ι may link hyperinsulinemia and other PKC-λ/ι activators to pathological and functional abnormalities in Alzheimer's disease.

An in vitro prototype of a porcine biomimetic testis-like cell culture system: a novel tool for the study of reassembled Sertoli and Leydig cells.

At present, there is no reliable in vitro assembled prepubertal testis-like biomimetic organ culture system designed to assess the functional effects of human gonadotropins on Sertoli and Leydig cells. Spermatogenesis is regulated by endocrine, paracrine, and juxtacrine factors (testicular cross-talk), mainly orchestrated by gonadotropins such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH) that play a pivotal role by stimulating Leydig and Sertoli cells, respectively. The aim of our study was to set up an in vitro prepubertal porcine bioengineered construct as a new model for experimental studies on reassembled Sertoli and Leydig cells. We have evaluated Sertoli and Leydig cells obtained from 15- to 20-day-old neonatal pig testes in terms of purity and function. Subsequently, purified Sertoli and enriched Leydig cells were subjected to coincubation to obtain an in vitro prepubertal porcine testis-like culture system. We performed enzyme-linked immunosorbent assay (ELISA) for anti-Müllerian hormone (AMH), inhibin B, and testosterone secretion in the medium, and Real-Time PCR analysis of AMH, inhibin B, FSH-r, aromatase, LHr, and 3ß-HSD mRNA expression levels. This in vitro testis-like system was highly responsive to the effects of human gonadotropins and testosterone. AMH mRNA expression and secretion declined, and inhibin-B increased, while FSH-receptor expression was downregulated upon FSH/LH exposure/treatment. Finally, the production of testosterone was increased selectively upon LH treatment. In summary, our proposed model could help to better determine the action of human gonadotropins on Sertoli and Leydig cells. The potential usefulness of the system for shedding light into male infertility-related issues is evident.

The metabolic state of diabetic monkeys is regulated by fibroblast growth factor-21.

Fibroblast growth factor (FGF)-21 has been recently characterized as a potent metabolic regulator. Systemic administration of FGF-21 reduced plasma glucose and triglycerides to near normal levels in genetically compromised diabetic rodents. Importantly, these effects were durable and did not come at the expense of weight gain, hypoglycemia, or mitogenicity. To explore the therapeutic properties of FGF-21 in a nongenetically modified primate species, and thus demonstrate the potential for efficacy in humans, we evaluated its bioactivity in diabetic nonhuman primates. When administered daily for 6 wk to diabetic rhesus monkeys, FGF-21 caused a dramatic decline in fasting plasma glucose, fructosamine, triglycerides, insulin, and glucagon. Of significant importance in regard to safety, hypoglycemia was not observed at any point during the study. FGF-21 administration also led to significant improvements in lipoprotein profiles, including lowering of low-density lipoprotein cholesterol and raising of high-density lipoprotein cholesterol, beneficial changes in the circulating levels of several cardiovascular risk markers/factors, and the induction of a small but significant weight loss. These data support the development of FGF-21 for the treatment of diabetes and other metabolic diseases.