Jean Hardies

Effect of Pioglitazone on Abdominal Fat Distribution and Insulin Sensitivity in Type 2 Diabetic Patients

We examined the effect of pioglitazone on abdominal fat distribution to elucidate the mechanisms via which pioglitazone improves insulin resistance in patients with type 2 diabetes mellitus. Thirteen type 2 diabetic patients (nine men and four women; age, 52 +/- 3 yr; body mass index, 29.0 +/- 1.1 kg/m(2)), who were being treated with a stable dose of sulfonylurea (n = 7) or with diet alone (n = 6), received pioglitazone (45 mg/d) for 16 wk. Before and after pioglitazone treatment, subjects underwent a 75-g oral glucose tolerance test (OGTT) and two-step euglycemic insulin clamp (insulin infusion rates, 40 and 160 mU/m(2).min) with [(3)H]glucose. Abdominal fat distribution was evaluated using magnetic resonance imaging at L4-5. After 16 wk of pioglitazone treatment, fasting plasma glucose (179 +/- 10 to 140 +/- 10 mg/dl; P < 0.01), mean plasma glucose during OGTT (295 +/- 13 to 233 +/- 14 mg/dl; P < 0.01), and hemoglobin A(1c) (8.6 +/- 0.4% to 7.2 +/- 0.5%; P < 0.01) decreased without a change in fasting or post-OGTT insulin levels. Fasting plasma FFA (674 +/- 38 to 569 +/- 31 microEq/liter; P < 0.05) and mean plasma FFA (539 +/- 20 to 396 +/- 29 microEq/liter; P < 0.01) during OGTT decreased after pioglitazone. In the postabsorptive state, hepatic insulin resistance [basal endogenous glucose production (EGP) x basal plasma insulin concentration] decreased from 41 +/- 7 to 25 +/- 3 mg/kg fat-free mass (FFM).min x microU/ml; P < 0.05) and suppression of EGP during the first insulin clamp step (1.1 +/- 0.1 to 0.6 +/- 0.2 mg/kg FFM.min; P < 0.05) improved after pioglitazone treatment. The total body glucose MCR during the first and second insulin clamp steps increased after pioglitazone treatment [first MCR, 3.5 +/- 0.5 to 4.4 +/- 0.4 ml/kg FFM.min (P < 0.05); second MCR, 8.7 +/- 1.0 to 11.3 +/- 1.1 ml/kg FFM(.)min (P < 0.01)]. The improvement in hepatic and peripheral tissue insulin sensitivity occurred despite increases in body weight (82 +/- 4 to 85 +/- 4 kg; P < 0.05) and fat mass (27 +/- 2 to 30 +/- 3 kg; P < 0.05). After pioglitazone treatment, sc fat area at L4-5 (301 +/- 44 to 342 +/- 44 cm(2); P < 0.01) increased, whereas visceral fat area at L4-5 (144 +/- 13 to 131 +/- 16 cm(2); P < 0.05) and the ratio of visceral to sc fat (0.59 +/- 0.08 to 0.44 +/- 0.06; P < 0.01) decreased. In the postabsorptive state hepatic insulin resistance (basal EGP x basal immunoreactive insulin) correlated positively with visceral fat area (r = 0.55; P < 0.01). The glucose MCRs during the first (r = -0.45; P < 0.05) and second (r = -0.44; P < 0.05) insulin clamp steps were negatively correlated with the visceral fat area. These results demonstrate that a shift of fat distribution from visceral to sc adipose depots after pioglitazone treatment is associated with improvements in hepatic and peripheral tissue sensitivity to insulin.

Effect of adipose tissue insulin resistance on metabolic parameters and liver histology in obese patients with nonalcoholic fatty liver disease

The role of adipose tissue insulin resistance in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) remains unclear. To evaluate this, we measured in 207 patients with NAFLD (age = 51 ± 1, body mass index = 34.1 ± 0.3 kg/m2) and 22 controls without NAFLD (no NAFLD) adipose tissue insulin resistance by means of a validated index (Adipo‐IRi = plasma free fatty acids [FFA] x insulin [FPI] concentration) and as the suppression of plasma FFA during an oral glucose tolerance test and by a low‐dose insulin infusion. We also explored the relationship between adipose tissue insulin resistance with metabolic and histological parameters by dividing them based on quartiles of adipose tissue insulin resistance (Adipo‐IRi quartiles: Q1 = more sensitive; Q4 = more insulin resistant). Hepatic insulin resistance, measured as an index derived from endogenous glucose production x FPI (HIRi), and muscle insulin sensitivity, were assessed during a euglycemic insulin clamp with 3‐[3H] glucose. Liver fat was measured by magnetic resonance imaging and spectroscopy, and a liver biopsy was performed to assess liver histology. Compared to patients without steatosis, patients with NAFLD were insulin resistant at the level of adipose tissue, liver, and skeletal muscle and had higher plasma aspartate aminotransferase and alanine aminotransferase, triglycerides, and lower high‐density lipoprotein cholesterol and adiponectin levels (all P < 0.01). Metabolic parameters, hepatic insulin resistance, and liver fibrosis (but not necroinflammation) deteriorated as quartiles of adipose tissue insulin resistance worsened (all P < 0.01). Conclusion: Adipose tissue insulin resistance plays a key role in the development of metabolic and histological abnormalities of obese patients with NAFLD. Treatment strategies targeting adipose tissue insulin resistance (e.g., weight loss and thiazolidinediones) may be of value in this population. (HEPATOLOGY 2012)

Regional Spatial Normalization: Toward an Optimal Target

Purpose The purpose of this work was to develop methods for defining, constructing, and evaluating a “minimal deformation target” (MDT) brain for multisubject studies based on analysis of the entire group. The goal is to provide a procedure that will create a standard, reproducible target brain image based on common features of a group of three-dimensional MR brain images. Method The average deformation and dispersion distance, derived from discrete three-dimensional deformation fields (DFs), are used to identify the best individual target (BIT) brain. This brain is assumed to be the one with the minimal deformation bias within a group of MR brain images. The BIT brain is determined as the one with the minimal target quality score, our cost function based on the deformation displacement and dispersion distance. The BIT brain is then transformed to the MDT brain using an average DF to create an optimized target brain. This analysis requires the calculation of a large number of DFs. To overcome this limitation, we developed an analysis method (the fast method) that reduces the task from order N2 complexity to one of order N, a tremendous advantage for large-N studies. Results Multiscale correlation analysis in a group of 20 subjects demonstrated the superiority of warping using the MDT target brain, made from the BIT brain, over several individual and MDT-transformed target brains also from the group. Conclusion Analysis of three-dimensional DF provides a means to quickly create a reproducible MDT target brain for any set of subjects. Warping to the MDT target was shown by an independent multiscale correlation method to produce superior results.

An optimized individual target brain in the Talairach coordinate system.

Abstract The goal of regional spatial normalization is to remove anatomical differences between individual three-dimensional brain images by warping them to match features of a single target brain. Current target brains are either an average, suitable for low-resolution brain mapping studies, or a single brain. While a single high-resolution target brain is desirable to match anatomical detail, it can lead to bias in anatomical studies. An optimization method to reduce the individual anatomical bias of the ICBM high-resolution brain template (HRBT), a high-resolution MRI target brain image used in many laboratories, is presented. The HRBT was warped to all images in a group of 27 normal subjects. Displacement fields were averaged to calculate the “minimal deformation target” (MDT) transformation for optimization. The greatest anatomical changes in the HRBT, following optimization, were observed in the superior precentral and postcentral gyri on the right, the right inferior occipital, the right posterior temporal lobes, and the lateral ventricles. Compared with the original HRBT, the optimized HRBT showed better anatomical matching to the group of 27 brains. This was quantified by the improvements in spatial cross-correlation and between the group of brains and the optimized HRBT (P

Long-Term Pioglitazone Treatment for Patients With Nonalcoholic Steatohepatitis and Prediabetes or Type 2 Diabetes Mellitus: A Randomized Trial

Nonalcoholic fatty liver disease (NAFLD) is reaching epidemic proportions worldwide (1) and is the most common chronic liver condition in obese patients with prediabetes or type 2 diabetes mellitus (T2DM). Histologic findings range from isolated steatosis (with no or minimal inflammation) to severe nonalcoholic steatohepatitis (NASH) and variable perisinusoidal or perivenular fibrosis (2). Patients with T2DM and NASH have the highest risk for cirrhosis and hepatocellular carcinoma (3, 4), and the presence of NAFLD seems to worsen microvascular and macrovascular complications of diabetes (57). Given that most patients with T2DM have NAFLD (812) and many are at risk for NASH even if they have normal liver aminotransferase levels (6, 9, 13, 14), it is surprising that few trials have focused on this population. This distinction (patients with NASH with vs. without T2DM) is relevant because additional metabolic factors, such as hyperglycemia (15, 16), lower adiponectin levels (17, 18), worse dyslipidemia (19, 20), and more severe insulin resistance and hepatic steatosis (10, 16, 1821), may account for the higher rates of severe liver disease observed in patients with T2DM (22). Although the cause of NASH is multifactorial and treatment remains challenging (23), a major factor is the increase in liver triglyceride content caused by chronic release of free fatty acids (FFAs) from insulin-resistant dysfunctional adipose tissue (7, 2427). Because thiazolidinediones target insulin resistance and adipose tissue dysfunction or inflammation that promotes hepatic lipotoxicity in NASH (7, 22, 28) (which is also a prominent feature of T2DM [15]), they may be more helpful for treating steatohepatitis in this population. In predominantly nondiabetic patients with NASH, several studies have reported variable degrees of histologic benefit with thiazolidinediones (2933). In the largest study to date in patients without T2DM (34), pioglitazone was no better than placebo for the primary outcome but was beneficial for secondary outcomes, such as resolution of NASH. However, in patients with prediabetes or T2DM, the only available randomized, controlled trial is a relatively small proof-of-concept study (35). This is disappointing given that there are 29.1 million adults with diabetes (>90% with T2DM) and 86 million with prediabetes (36) in the United States, many of whom are at risk for cirrhosis from NASH. Moreover, because pioglitazone may also halt the progression of prediabetes to T2DM (37), defining its role in patients with prediabetes and NASH is critical. Finally, safety concerns about the long-term use of thiazolidinediones remain (38, 39); therefore, studies with extended thiazolidinedione exposure are needed before a pioglitazone-based approach can be embraced in this population. The aim of our study was to assess the efficacy and safety of long-term pioglitazone treatment in improving liver histologic outcomes in patients with NASH and prediabetes or T2DM. Methods Design Overview This was a single-center, parallel-group, randomized (1:1 allocation), placebo-controlled study, conducted between December 2008 (first patient enrolled) and December 2014 (final data collection). Participants, investigators, and health care providers were blinded to treatment assignment throughout the study. The Institutional Review Board at the University of Texas Health Science Center at San Antonio (UTHSCSA) approved the study, and all participants provided written informed consent before enrollment. In October 2009, while updating registry data for another study, investigators discovered that this trial, which they thought had been registered by other study personnel, was not registered. At the time of registration (ClinicalTrials.gov: NCT00994682), 29 patients (of 97 anticipated) were enrolled in the study. None of these patients had had the follow-up metabolic measurements or liver biopsies (primary outcome) that were to be performed at 18 months, and no interim analyses were done before the trial was registered. A recent review of ClinicalTrials.gov (November 2015) revealed that the initial trial registration data erroneously stated that patients with normal glucose tolerance would be randomly assigned to treatment or placebo. Given that the trials eligibility criteria required patients to have an abnormal oral glucose tolerance test (OGTT) result (that is, prediabetes or T2DM), the investigators never planned to enroll patients with normal glucose tolerance. This error in trial registration was corrected by the principal investigator. The trial registry states that the primary end point is liver histologic outcomes (Kleiner criteria [40]) at 18 months, and these data are presented in Appendix Table 1. In this article, the primary end point is defined as a reduction of at least 2 points in 2 categories of the NAFLD activity score (NAS) without worsening of fibrosis, an outcome that was not specified in the original registration. This end point has been accepted by investigators in this field as representing significant change in liver histologic outcomes in clinical trials involving patients with NASH (34, 4143). Some secondary outcomes that were assessed, such as insulin secretion, prevention of the onset of T2DM or reversal of glucose intolerance, measurement of visceral fat by magnetic resonance imaging, bone density measurement via dual-energy x-ray absorptiometry (DXA), plasma measurements of bone metabolism, and molecular metabolic pathways, are not reported in this article. Appendix Table 1. Liver Histologic Variables at Baseline and After 18 mo, Based on Observed Data* Setting and Participants Participants were recruited from the general population of San Antonio, Texas, via newspaper advertisements and from the endocrinology and hepatology clinics at UTHSCSA and the Veterans Affairs Medical Center. Persons were eligible for the trial if they had histologically confirmed NASH and either prediabetes or T2DM. All patients had a screening 2-hour OGTT to diagnose or confirm a diagnosis of prediabetes or T2DM. Prediabetes was defined as impaired fasting glucose (5.6 to 6.9 mmol/L [100 to 125 mg/dL]), impaired glucose tolerance (7.8 to 11.1 mmol/L [140 to 199 mg/dL] on an OGTT), or a hemoglobin A1c level of 5.7% to 6.4%. Exclusion criteria included use of thiazolidinediones or vitamin E; other causes of liver disease (22) or abnormal laboratory results (such as an aspartate aminotransferase [AST] or alanine aminotransferase [ALT] level 3 times the upper limit of normal [ULN]); type 1 diabetes mellitus; or severe heart, hepatic, or renal disease. Detailed inclusion and exclusion criteria are provided in the Appendix. Randomization and Interventions After initial screening (medical history, physical examination, laboratory tests, and 75-g OGTT), patients began receiving placebo and were instructed by the research dietician (C.D.) to keep physical activity and diet constant during the run-in phase (mean duration, 1 month). After completion of baseline metabolic measurements, participants were prescribed a hypocaloric diet (500kcal/d deficit from the calculated weight-maintaining diet) and were randomly assigned in a 1:1 ratio to either pioglitazone (Actos [Takeda Pharmaceuticals]), 30 mg/d (titrated after 2 months to 45 mg/d), or placebo. Randomization (computer-generated) and patient allocation were performed by the research pharmacist without stratification and using a block factor of 4, which was unknown to investigators. Takeda Pharmaceuticals provided pioglitazone and placebo pills with identical physical characteristics, which were stored at the research pharmacy and dispensed in identical bottles. Outcomes and Follow-up The primary outcome was a reduction of at least 2 points in 2 histologic categories of the NAS without worsening of fibrosis after 18 months of therapy. Secondary liver histologic outcomes included resolution of NASH; improvement in individual histologic scores; or improvement in a combined histologic outcome, defined as a reduction in ballooning with at least a 2-point improvement in the NAS or an absolute NAS of 3 or lower (with improvement in steatosis or inflammation) without worsening of fibrosis. Baseline liver biopsy specimens were read by a team of experienced clinical pathologists to establish or rule out the presence of NASH and thus determine whether patients were included or excluded. At the end of the study, all biopsy specimens were reread by an experienced research pathologist (F.T.), who was blinded to patient identity, intervention assignment, and pretreatment or posttreatment sequence (0, 18, or 36 months). Biopsy specimens were read by the research pathologist 2 times, with good to excellent intraobserver variability (agreement >75% for all histologic parameters). Diagnosis of definite NASH was defined as zone 3 accentuation of macrovesicular steatosis (any grade), hepatocellular ballooning (any degree), and lobular inflammatory infiltrates (any amount). The NAS was calculated as the sum of the steatosis, inflammation, and ballooning grades from the liver biopsy, and histopathologic changes were determined by using standard criteria (44). Additional secondary outcomes included the following: 1) fasting plasma glucose, fasting plasma insulin, FFA, hemoglobin A1c, fasting plasma lipid profile, adiponectin, and cytokeratin-18 concentrations; 2) total body fat percentage, measured by DXA; 3) hepatic triglyceride content, measured by magnetic resonance and proton spectroscopy (1H-MRS) as previously described (14, 16, 35, 45) (baseline and 18 months only); 4) glucose tolerance and insulin secretion on an OGTT; 5) endogenous glucose production (EGP), rate of glucose disappearance (R d), and insulin-induced suppression of EGP and plasma FFA concentration, all measured during a euglycemic insulin clamp with tritiated glucose and indirect calorimetry (baseline and 18 months only) as previously reported (16

Nonlinear coupling between cerebral blood flow, oxygen consumption, and ATP production in human visual cortex.

The purpose of this study was to investigate activation-induced hypermetabolism and hyperemia by using a multifrequency (4, 8, and 16 Hz) reversing-checkerboard visual stimulation paradigm. Specifically, we sought to (i) quantify the relative contributions of the oxidative and nonoxidative metabolic pathways in meeting the increased energy demands [i.e., ATP production (JATP)] of task-induced neuronal activation and (ii) determine whether task-induced cerebral blood flow (CBF) augmentation was driven by oxidative or nonoxidative metabolic pathways. Focal increases in CBF, cerebral metabolic rate of oxygen (CMRO2; i.e., index of aerobic metabolism), and lactate production (JLac; i.e., index of anaerobic metabolism) were measured by using physiologically quantitative MRI and spectroscopy methods. Task-induced increases in JATP were small (12.2–16.7%) at all stimulation frequencies and were generated by aerobic metabolism (approximately 98%), with %ΔJATP being linearly correlated with the percentage change in CMRO2 (r = 1.00, P < 0.001). In contrast, task-induced increases in CBF were large (51.7–65.1%) and negatively correlated with the percentage change in CMRO2 (r = −0.64, P = 0.024), but positively correlated with %ΔJLac (r = 0.91, P < 0.001). These results indicate that (i) the energy demand of task-induced brain activation is small (approximately 15%) relative to the hyperemic response (approximately 60%), (ii) this energy demand is met through oxidative metabolism, and (iii) the CBF response is mediated by factors other than oxygen demand.

Prevalence of Prediabetes and Diabetes and Metabolic Profile of Patients With Nonalcoholic Fatty Liver Disease (NAFLD)

OBJECTIVE Prediabetes and type 2 diabetes mellitus (T2DM) are believed to be common and associated with a worse metabolic profile in patients with nonalcoholic fatty liver disease (NAFLD). However, no previous study has systematically screened this population. RESEARCH DESIGN AND METHODS We studied the prevalence and the metabolic impact of prediabetes and T2DM in 118 patients with NAFLD. The control group comprised 20 subjects without NAFLD matched for age, sex, and adiposity. We measured 1) plasma glucose, insulin, and free fatty acid (FFA) concentration during an oral glucose tolerance test; 2) liver fat by magnetic resonance spectroscopy (MRS); 3) liver and muscle insulin sensitivity (euglycemic insulin clamp with 3-[3H]glucose); and 4) indexes of insulin resistance (IR) at the level of the liver (HIRi= endogenous glucose production × fasting plasma insulin [FPI]) and adipose tissue (Adipo-IRi= fasting FFA × FPI). RESULTS Prediabetes and T2DM was present in 85% versus 30% in controls (P < 0.0001), all unaware of having abnormal glucose metabolism. NAFLD patients were IR at the level of the adipose tissue, liver, and muscle (all P < 0.01–0.001). Muscle and liver insulin sensitivity were impaired in patients with NAFLD to a similar degree, whether they had prediabetes or T2DM. Only adipose tissue IR worsened in T2DM and correlated with the severity of muscle (r = 0.34; P < 0.001) and hepatic (r = 0.57; P < 0.0001) IR and steatosis by MRS (r = 0.35; P < 0.0001). CONCLUSIONS Patients with NAFLD may benefit from early screening for T2DM, because the prevalence of abnormal glucose metabolism is much higher than previously appreciated. Regardless of glucose tolerance status, severe IR is common. In patients with T2DM, adipose tissue IR appears to play a major role in the severity of NAFLD.

Processing speed is correlated with cerebral health markers in the frontal lobes as quantified by neuroimaging.

We explored relationships between decline in cognitive processing speed (CPS) and change in frontal lobe MRI/MRS-based indices of cerebral integrity in 38 healthy adults (age 57-90 years). CPS was assessed using a battery of four timed neuropsychological tests: Grooved Pegboard, Coding, Symbol Digit Modalities Test and Category Fluency (Fruits and Furniture). The neuropsychological tests were factor analyzed to extract two components of CPS: psychomotor (PM) and psychophysical (PP). MRI-based indices of cerebral integrity included three cortical measurements per hemisphere (GM thickness, intergyral and sulcal spans) and two subcortical indices (fractional anisotropy (FA), measured using track-based spatial statistics (TBSS), and the volume of hyperintense WM (HWM)). MRS indices included levels of choline-containing compounds (GPC+PC), phosphocreatine plus creatine (PCr+Cr), and N-acetylaspartate (NAA), measured bilaterally in the frontal WM bundles. A substantial fraction of the variance in the PM-CPS (58%) was attributed to atrophic changes in frontal WM, observed as increases in sulcal span, declines in FA values and reductions in concentrations of NAA and choline-containing compounds. A smaller proportion (20%) of variance in the PP-CPS could be explained by bilateral increases in frontal sulcal span and increases in HWM volumes.

Pioglitazone in the treatment of NASH: the role of adiponectin

Background  Plasma adiponectin is decreased in NASH patients and the mechanism(s) for histological improvement during thiazolidinedione treatment remain(s) poorly understood.

Mapping Structural Differences of the Corpus Callosum in Individuals With 18q Deletions Using Targetless Regional Spatial Normalization

Individuals with a constitutional chromosome abnormality consisting of a deletion of a portion of the long arm of chromosome 18 (18q−) have a high incidence (∼95%) of dysmyelination. Neuroradiologic findings in affected children report a smaller corpus callosum, but this finding has not been quantified. This is in part due to the large intersubject variability of the corpus callosum size and shape and the small number of subjects with 18q−, which leads to low statistical power for comparison with typically developing children. An analysis method called targetless spatial normalization (TSN) was used to improve the sensitivity of statistical testing. TSN converges all images in a group into what is referred as group common space. The group common space conserves common shape, size, and orientation while reducing intragroup variability. TSN in conjunction with a Witelson vertical partitioning scheme was used to assess differences in corpus callosum size between 12 children with 18q− and 12 age‐matched normal controls. Significant global and regional differences in corpus callosum size were seen. The 18q− group showed an overall smaller (25%) corpus callosum (P < 10−7), even after correction for differences in brain size. Regionally, the posterior portions of corpus callosum (posterior midbody, isthmus, and splenium), which contain heavily myelinated fibers, were found to be 25% smaller in the population with 18q−. Hum Brain Mapping 24:325–331, 2005.