Sodium-glucose cotransporter 2 inhibition does not reduce hepatic steatosis in overweight, insulin-resistant patients without type 2 diabetes

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is rapidly becoming the leading indication for liver transplant and is associated with increased cardiovascular and liver mortality, yet there are no licensed therapies. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are widely used for their glucose-lowering effects in patients with type 2 diabetes (T2D). Preclinical models have suggested a beneficial impact on NAFLD, but clinical data are limited, and there are currently no data on patients without T2D. We aimed to investigate the impact of SGLT2 inhibition on NAFLD in overweight, nondiabetic patients and establish the effect these agents may have on the processes that regulate hepatic steatosis in vivo.

METHODS

We conducted an open-label, experimental medicine pilot study on insulin-resistant overweight/obese individuals (n = 10) using gold-standard noninvasive assessments of NAFLD phenotype, including magnetic resonance spectroscopy, two-step hyperinsulinemic euglycemic clamps, and stable isotope tracers to assess lipid and glucose metabolism. Investigations were performed before and after a 12-week treatment with the SGLT2 inhibitor, dapagliflozin.

RESULTS

Despite a body weight reduction of 4.4 kg, hepatic steatosis was unchanged following treatment. Hepatic glucose production increased, and there was impairment of glucose disposal during the low-dose insulin infusion. Although circulating, nonesterified, fatty acid levels did not change, the ability of insulin to suppress lipolysis was reduced.

CONCLUSIONS

SGLT2 inhibition for 12 weeks does not improve hepatic steatosis in patients without T2D. Additional studies in patients with established T2D or impairments of fasting or postprandial glucose homeostasis are needed to determine whether SGLT2 inhibition represents a viable therapeutic strategy for NAFLD. (http://clinicaltrials.gov Number NCT02696941).

Hepatic de novo lipogenesis is suppressed and fat oxidation is increased by omega-3 fatty acids at the expense of glucose metabolism

OBJECTIVE

Increased hepatic de novo lipogenesis (DNL) is suggested to be an underlying cause in the development of nonalcoholic fatty liver disease and/or insulin resistance. It is suggested that omega-3 fatty acids (FA) lower hepatic DNL. We investigated the effects of omega-3 FA supplementation on hepatic DNL and FA oxidation using a combination of human in vivo and in vitro studies.

RESEARCH DESIGN AND METHODS

Thirty-eight healthy men were randomized to take either an omega-3 supplement (4 g/day eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA) as ethyl esters) or placebo (4 g/day olive oil) and fasting measurements were made at baseline and 8 weeks. The metabolic effects of omega-3 FAs on intrahepatocellular triacylglycerol (IHTAG) content, hepatic DNL and FA oxidation were investigated using metabolic substrates labeled with stable-isotope tracers. In vitro studies, using a human liver cell-line was undertaken to gain insight into the intrahepatocellular effects of omega-3 FAs.

RESULTS

Fasting plasma TAG concentrations significantly decreased in the omega-3 group and remained unchanged in the placebo group. Eight weeks of omega-3 supplementation significantly decreased IHTAG, fasting and postprandial hepatic DNL while significantly increasing dietary FA oxidation and fasting and postprandial plasma glucose concentrations. In vitro studies supported the in vivo findings of omega-3 FAs (EPA+DHA) decreasing intracellular TAG through a shift in cellular metabolism away from FA esterification toward oxidation.

CONCLUSIONS

Omega-3 supplementation had a potent effect on decreasing hepatic DNL and increasing FA oxidation and plasma glucose concentrations. Attenuation of hepatic DNL may be considered advantageous; however, consideration is required as to what the potential excess of nonlipid substrates (eg, glucose) will have on intrahepatic and extrahepatic metabolic pathways.

TRIAL REGISTRATION NUMBER

NCT01936779.

Renal trauma and the intravenous urogram

A retrospective analysis of all patients with blunt abdominal trauma associated with haematuria admitted to one hospital (Royal United, Bath) in a 10-year period was conducted to establish the contribution of the intravenous urogram (IVU) in their management. Eighty-one case records were analysed. Of 35 IVUs performed in patients with microscopic (reagentstrip positive) haematuria, only one was abnormal. In contrast, 27 IVUs performed in patients with macroscopic (naked eye) haematuria revealed 17 major injuries and 5 previously unrecognized congenital abnormalities. It is concluded that an IVU is an unnecessary and non-contributory investigation in patients with microscopic haematuria and guidelines are suggested for the role of IVU in patients with blunt abdominal trauma associated with haematuria.

Neural cell adhesion molecule (NCAM) and myoblast fusion

Considerable evidence points to an involvement of neural cell adhesion molecule (NCAM) in myoblast fusion. Changes in the level of NCAM expression, isoform specificity, and localization in muscle cells and tissues correspond to key morphogenetic events during muscle differentiation and repair. Furthermore, anti-NCAM antibodies have been shown by others to reduce the rate of myoblast fusion, whereas overexpression of NCAM cDNAs increases the rate of myoblast fusion compared to controls. In this study we have used a novel fusion assay based on intracistronic complementation of lacZ, in combination with fluorescent X-gal histochemistry and immunocytochemistry to assess levels of NCAM expression in individual muscle cells. Our results indicate that a substantial proportion of newly fused myoblasts have NCAM expression levels unchanged from the levels of the surrounding unfused population suggesting that increased expression of NCAM is not required for wild-type myoblasts to fuse. Moreover, pure populations of primary myoblasts isolated from mice homozygous null for NCAM and therefore lacking the molecule, when placed in differentiation medium, consistently fused to form contractile myotubes with kinetics equivalent to wild-type primary myoblasts. We conclude that the increase in expression of NCAM, although typically observed during myogenesis, is not essential to myoblast fusion to form myotubes.

The phosphoprotein protein PEA-15 inhibits Fas- but increases TNF-R1-mediated caspase-8 activity and apoptosis

We have characterized a phosphoprotein protein with a death effector domain that has a novel bifunctional role in programmed cell death. The 15-kDa phosphoprotein enriched in astrocytes (PEA-15) inhibits Fas-mediated apoptosis and increases tumor necrosis factor receptor-1 (TNF-R1)-mediated apoptosis in the same cell type in a ligand-dependent manner. Phosphorylation appears to play a role in its differential effects, since point mutations at one or both phosphorylation consensus sites within PEA-15 destroy its effect on Fas-mediated, but not TNF-R1-mediated, apoptosis. Furthermore, the differential effect is evident at the level of caspase-8 activity which is inhibited via Fas activation, but increased via TNF-R1 activation upon PEA-15 expression. These results show that PEA-15 provides a potential mechanism during development for distinguishing between diverse extracellular death-inducing signals that culminate either in apoptosis or in survival.

Monitoring protein-protein interactions in intact eukaryotic cells by beta-galactosidase complementation

We present an approach for monitoring protein-protein interactions within intact eukaryotic cells, which should increase our understanding of the regulatory circuitry that controls the proliferation and differentiation of cells and how these processes go awry in disease states such as cancer. Chimeric proteins composed of proteins of interest fused to complementing beta-galactosidase (beta-gal) deletion mutants permit a novel analysis of protein complexes within cells. In this approach, the beta-gal activity resulting from the forced interaction of nonfunctional weakly complementing beta-gal peptides (Deltaalpha and Deltaomega) serves as a measure of the extent of interaction of the non-beta-gal portions of the chimeras. To test this application of lacZ intracistronic complementation, proteins that form a complex in the presence of rapamycin were used. These proteins, FRAP and FKBP12, were synthesized as fusion proteins with Deltaalpha and Deltaomega, respectively. Enzymatic beta-gal activity served to monitor the formation of the rapamycin-induced chimeric FRAP/FKBP12 protein complex in a time- and dose-dependent manner, as assessed by histochemical, biochemical, and fluorescence-activated cell sorting assays. This approach may prove to be a valuable adjunct to in vitro immunoprecipitation and crosslinking methods and in vivo yeast two-hybrid and fluorescence energy transfer systems. It may also allow a direct assessment of specific protein dimerization interactions in a biologically relevant context, localized in the cell compartments in which they occur, and in the milieu of competing proteins.

Fusion competence of myoblasts rendered genetically null for N-cadherin in culture

Myoblast fusion is essential to muscle tissue development yet remains poorly understood. N-cadherin, like other cell surface adhesion molecules, has been implicated by others in muscle formation based on its pattern of expression and on inhibition of myoblast aggregation and fusion by antibodies or peptide mimics. Mice rendered homozygous null for N-cadherin revealed the general importance of the molecule in early development, but did not test a role in skeletal myogenesis, since the embryos died before muscle formation. To test genetically the proposed role of N-cadherin in myoblast fusion, we successfully obtained N-cadherin null primary myoblasts in culture. Fusion of myoblasts expressing or lacking N-cadherin was found to be equivalent, both in vitro by intracistronic complementation of lacZ and in vivo by injection into the muscles of adult mice. An essential role for N-cadherin in mediating the effects of basic fibroblast growth factor was also excluded. These methods for obtaining genetically homozygous null somatic cells from adult tissues should have broad applications. Here, they demonstrate clearly that the putative fusion molecule, N-cadherin, is not essential for myoblast fusion.

Spectrophotometric quantitation of tissue culture cell number in any medium

We have developed a spectrophotometric assay for cell number in suspensions of tissue culture cells. For each cell type tested, absorbance between 650 and 800 nm is linearly dependent upon cell density over a 50-fold range and is independent of the color or composition of the medium in which cells are suspended. A standard curve of absorbance vs. cell density is used to estimate cell number with accuracy and reproducibility superior to hemacytometer counting and with speed and ease surpassing use of a Coulter counter. Less than 5000 cells are needed for this quantitation. The same cells that are counted can be maintained live in culture after the reading is taken, thus allowing the growth of cells to be measured within individual cultures over time. The assay should be readily extended to assays of cell number directly within microplate culture wells. The spectrophotometric assay described here is of significant use in all experiments requiring rapid, accurate measurements of cell number, including determinations of cell doubling time and equal plating of parallel cultures.

Urethral catheterisation--is anybody listening?

All house officers perform male urethral catheterisation and although complications may occur awareness of the potential problems varies considerably. 43 house officers from 12 different medical schools were interviewed to determine the amount of training that they received regarding this procedure as students and during their first pre-registration post. The results suggest that there is no planned approach to teaching urethral catheterisation which would be in the interests of both junior doctors and patients alike.

Penetration of Autographa californica nuclear polyhedrosis virus nucleocapsids into IPLB Sf 21 cells induces actin cable formation

The budded form of Autographa californica nuclear polyhedrosis virus functionally enters cells by adsorptive endocytosis. During the period of virus uptake into Spodoptera frugiperda IPLB Sf21 cells (1 to 4 hr postinfection), filamentous F-actin cables, visualized by fluorescence microscopy, were formed within the cytoplasm of infected cells. Cable formation appeared to be a direct effect of viral inoculum in that the numbers of observed cables increased with an increase in multiplicity of infection, and cable formation was not dependent on protein synthesis. Cable induction was first apparent around 30 min postinfection, although uptake of virus into endocytic vesicles began much earlier. Chloroquine, a chemical that prevents release of nucleocapsids from endosomes, inhibited cable formation. Similarly, when virus adsorbed to the exterior of cells was exposed to neutralizing antibody, release of nucleocapsids from endosomes and subsequent cable induction were prevented. Careful observation of co-labeled F-actin cables and nucleocapsids revealed a single nucleocapsid at an end of most cables. These results suggested that nucleocapsids or nucleocapsid-associated proteins of budded virus induced the polymerization or bundling of actin following their penetration into the cytoplasm from endocytic vesicles.

Indications for conservative management of acute scrotal pain in children

Forty-three boys who presented with acute scrotal pain were studied retrospectively. Of these, 40 had torsion of scrotal contents. Torsion of testicular appendages, a self limiting condition, tended to present later than testicular torsion (P = 0.002). The testis was saved in all 11 cases of testicular torsion explored within 12h of the onset of pain but orchidectomy was required in four who presented later. In 11 cases, a torted testicular appendage diagnosed as a tender nodule was found on examining the upper pole of the testis. The remaining 14 cases of torted appendage were diagnosed at operation because testicular torsion could not be excluded due to scrotal swelling. Most (12) of this operated group were not seen until 3 days after the onset of pain. This study suggested that urgent operation was unnecessary in those in whom a tender nodule was found (pathognomonic of a torted appendage) and in those presenting after more than 24h of pain with scrotal erythema and oedema. The likely diagnosis in the latter case is a torted appendage and in cases of torsion of the testis there is no prospect of salvage at this stage. These guidelines were applied to a group of 20 boys studied prospectively. In eight, all with less than 24h of pain, immediate exploration was undertaken and testicular torsion was confirmed in six. The remaining 12 fulfilled the criteria for conservative management and were observed. All had normal testes at late review. Careful clinical assessment in boys with scrotal pain indicates which cases may be treated by non-operative management without fear of losing a salvageable testis.

A 5-year follow-up of undiagnosed haematuria

Eighty-four patients with haematuria were seen during 1976 and 1977. This symptom was investigated but no definite cause could be found. Five or more years later they were followed up. Although some patients had experienced further urological symptoms, none was found to have developed a malignancy in the genito-urinary tract. Possible causes of their bleeding are discussed.

Pharmacokinetics of metronidazole given to horses by intravenous and oral routes

Serum and peritoneal fluid concentrations of metronidazole were determined in 6 healthy adult horses given the drug (25 mg/kg) by IV or oral routes. The disposition of metronidazole in horses given the drug by the IV route conformed to a 2-compartment model with a distribution half-life of 0.16 hours, an elimination half-life of 2.9 hours, and a body clearance of 0.40 +/- 0.05 L/kg/hr. The oral absorption half-life was 0.40 hours, and the bioavailability, 85.0 +/- 18.6%. Peritoneal fluid concentrations were approximately equal to serum concentrations at all times, regardless of the route of administration. On the basis of reported minimal inhibitory concentrations for anaerobic bacteria, a dosage of 15 to 25 mg/kg given orally 4 times daily was recommended.

Deficient urinary fibrinolysis in renal stone disease

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What does the antimitochondrial antibody mean?

In a prospective survey positive antimitochondrial antibodies have been detected in 69/4200 (1.64%) of all sera submitted to a routine immunology laboratory. Of the 69, only nine patients had uniquivocal primary biliary cirrhosis, six others had chronic active hepatitis, 10 had abnormal liver function tests without evidence of primary biliary cirrhosis, while the remaining 44 had no clinical or biochemical evidence of liver disease. Outside the context of liver disease antimitochondrial antibodies were observed with similar frequency in patients with autoimmune disorders as in other conditions. It was not possible to distinguish primary biliary cirrhosis from patients without liver disease by antibody titre or by immunoglobulin subclass. The positive antimitochondrial antibody patients without liver disease were uniformly distributed throughout the city of Sheffield, in contrast with the marked clustering of cases of primary biliary cirrhosis. We conclude that, in the absence of clinical liver disease, the antimitochondrial antibody test alone (as detected by routine immunofluorescent techniques) does not appear to be a specific screening test for primary biliary cirrhosis. While we cannot exclude the possibility that the autoantibody indicates a predisposition to develop primary biliary cirrhosis, further prospective studies are needed to determine which patients will progress in this manner. The possibility that environmental factors may be implicated cannot be discounted.

Three-day and ten-day chemotherapy for urinary tract infections in general practice

The length of a course of antibiotic treatment for urinary tract infection varies with the habits of the prescriber. Many patients do not complete a course of treatment once their symptoms have subsided. In uncomplicated urinary tract infection among women seen in general practice a three-day course of amoxycillin was as effective as a 10-day course of the same drug in the same dose. Relief of symptoms was equal in both groups and bacteriuria was eliminated equally successfully in both regimens. There was no significant difference between the two groups in the incidence of side effects from the drugs. The financial saving which could accrue from adopting this therapeutic regimen would be significant.

A computer-based record and organisation system for a department of urology

This paper describes the development and practical application of a computer-based record system in a urological department. It demonstrates how such a system can provide a clinical flow sheet for day-to-day use combined with a computerised data store for both clinical evaluation and for research purposes. The paper also outlines how the system has improved patient handling and general departmental efficiency.

An anomalous calyx in the mid-kidney: an anatomical variant

Three cases in which there was an anomalous short calyx without a papilla in the mid kidney are described. This is believed to be a developmental abnormality which is associated with a pelvicalyceal pattern of two major calyces, and with renal "pseudotumour". It is important to recognize this calyceal appearance in order to distinguish it from calyceal disease.

Fibrinolytic activity in blood and urine

The blood and urinary fibrinolytic activities were simultaneously estimated in 14 ;normal' patients under basal conditions on successive days. No direct correlation between the fibrinolytic activities in the blood and urine was demonstrated. The origin of urokinase is discussed.