Explore This Program

The Program in Nutritional Metabolism is a multidisciplinary program with the goal of extending research through collaborations with multiple departments. It was founded in 2001 and explores eight major areas of study in metabolism and nutrition, including pediatric nutrition, with emphasis on development and bone health, HIV, Vitamin D metabolism, genomic and metabolomics, epidemiology, obesity and appetite regulation, and nutrient trafficking. These areas are explored across a broad number of disease conditions, including undernutrition, obesity and acquired lipodystrophy, for example among HIV-infected patients.

Related interests include the interplay between adipose tissue and innate immune activation, and the inflammatory basis of cardiovascular diseases. Faculty members, and collaborators with expertise spanning the entire field of nutrition and representing a broad array of interests including neuroendocrinology, pediatric endocrinology, infectious diseases, nutrition, cardiology, radiology and general medicine utilize state-of-the-art techniques such as insulin clamp, positron emission tomography (PET), magnetic resonance spectroscopy and novel imaging techniques to determine metabolic function and substrate flux.

Prior studies have investigated the use of a novel hypothalamic peptide to selectively reduce visceral fat in central obesity and among NAFLD patients, and a strategy to block inflammation in obesity with TNF-alpha antagonism. Among children with obesity, the relationship of mitochondrial function to insulin resistance has been studied. A major investigative focus has been to study cardiometabolic disease in women, with the first demonstration of unique patterns of cardiac steatosis in this group.


Metabolism Unit Faculty

Collaborating Faculty

Prominent Grants


Associated Faculty

NORCH Center Associate Director for Core Development (5P30DK040561-24)

Elizabeth Lawson, MD

NORCH Pilot and Feasibility (5P30DK040561-24)

Vibha Singhal, MD, MBBS

Co-Investigator on R01 (5R01DK114144-03)

Martin Torriani, MD; Takara Stanley, MD

Principal Investigator of MGH site for REPRIEVE (5U01HL123336-06)

Rajesh Gandhi, MD

Co-Investigator on R01 (5R01HL146267-02)

Gregory Robbins, MD; Markella Zanni, MD

Genetics R01 (1R01HL151283-01A1)

Pradeep Natarajan, MD; Steven Grinspoon, MD; Markella Zanni, MD

Principal Investigator of REPRIEVE (DCC) 5U01HL123339-04

Udo Hoffmann, MD

Co-Investigator on R01 (5R01HL146267-02)

Virginia Triant, MD, MPH; Markella Zanni, MD

Director of Metabolic Imaging Core for NORCH (5P30DK040561-24)

Martin Torriani, MD

Prominent Publications

Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, multicentre trial

Stanley TL, Fourman LT, Feldpausch MN, Purdy J, Zheng I, Pan CS, Aepfelbacher J, Buckless C, Tsao A, Kellogg A, Branch K, Lee H, Liu CY, Corey KE, Chung RT, Torriani M, Kleiner DE, Hadigan CM, Grinspoon SK. Effects of tesamorelin on non-alcoholic fatty liver disease in HIV: a randomised, double-blind, multicentre trial. Lancet HIV. 2019 Dec;6(12):e821-e830. doi: 10.1016/S2352-3018(19)30338-8. Epub 2019 Oct 11. PMID: 31611038; PMCID: PMC6981288.


Background: Non-alcoholic fatty liver disease (NAFLD) is a substantial cause of comorbidity in people with HIV and there are no proven pharmacological treatments for the disease in this population. We assessed the effects of tesamorelin on liver fat and histology in people with HIV and NAFLD.

Methods: This randomised, double-blind, multicentre study with identical placebo as a comparator was done in a hospital and a medical research centre in the USA. People with HIV infection and a hepatic fat fraction (HFF) of 5% or more by proton magnetic resonance spectroscopy were eligible. Participants were randomly assigned (1:1) to receive either tesamorelin 2 mg once daily or placebo once daily for 12 months, followed by a 6-month open-label phase during which all participants received tesamorelin 2 mg daily. The randomisation list was prepared by the study statistician using a permuted block algorithm within each stratum with randomly varying block sizes. The primary endpoint was change in HFF between baseline and 12 months. The primary safety endpoint was glucose. Analysis was by intention to treat using all available data. This trial is registered with ClinicalTrials.gov, number NCT02196831.

Findings: 61 patients were enrolled between Aug 20, 2015, and Jan 16, 2019, of whom 30 received tesamorelin and 30 received placebo. Patients receiving tesamorelin had a greater reduction of HFF than did patients receiving placebo, with an absolute effect size of -4·1% (95% CI -7·6 to -0·7, p=0·018), corresponding to a -37% (95% CI -67 to -7, p=0·016) relative reduction from baseline. After 12 months, 35% of individuals receiving tesamorelin and 4% receiving placebo had a HFF of less than 5% (p=0·0069). Changes in fasting glucose and glycated haemoglobin were not different between groups at 12 months. Individuals in the tesamorelin group experienced more localised injection site complaints than those in the placebo group, though none were judged to be serious.

Interpretation: Tesamorelin might be beneficial in people with HIV and NAFLD. Further studies are needed to determine the long-term effects of tesamorelin on liver histology.

Funding: National Institutes of Health and National Institute of Allergy and Infectious Diseases.

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Effects of statin therapy on coronary artery plaque volume and high-risk plaque morphology in HIV-infected patients with subclinical atherosclerosis: a randomised, double-blind, placebo-controlled trial

Lo J, Lu MT, Ihenachor EJ, Wei J, Looby SE, Fitch KV, Oh J, Zimmerman CO, Hwang J, Abbara S, Plutzky J, Robbins G, Tawakol A, Hoffmann U, Grinspoon SK. Effects of statin therapy on coronary artery plaque volume and high-risk plaque morphology in HIV-infected patients with subclinical atherosclerosis: a randomised, double-blind, placebo-controlled trial. Lancet HIV. 2015 Feb;2(2):e52-63. doi: 10.1016/S2352-3018(14)00032-0. Epub 2015 Jan 9. PMID: 26424461; PMCID: PMC4820828.


Background: HIV-infected patients have a high risk of myocardial infarction. We aimed to assess the ability of statin treatment to reduce arterial inflammation and achieve regression of coronary atherosclerosis in this population.

Methods: In a randomised, double-blind, placebo-controlled trial, 40 HIV-infected participants with subclinical coronary atherosclerosis, evidence of arterial inflammation in the aorta by fluorodeoxyglucose (FDG)-PET, and LDL-cholesterol concentration of less than 3.37 mmol/L (130 mg/dL) were randomly assigned (1:1) to 1 year of treatment with atorvastatin or placebo. Randomisation was by the Massachusetts General Hospital (MGH) Clinical Research Pharmacy with a permuted-block algorithm, stratified by sex with a fixed block size of four. Study codes were available only to the MGH Research Pharmacy and not to study investigators or participants. The prespecified primary endpoint was arterial inflammation as assessed by FDG-PET of the aorta. Additional prespecified endpoints were non-calcified and calcified plaque measures and high risk plaque features assessed with coronary CT angiography and biochemical measures. Analysis was done by intention to treat with all available data and without imputation for missing data. The trial is registered with ClinicalTrials.gov, number NCT00965185.

Findings: The study was done from Nov 13, 2009, to Jan 13, 2014. 19 patients were assigned to atorvastatin and 21 to placebo. 37 (93%) of 40 participants completed the study, with equivalent discontinuation rates in both groups. Baseline characteristics were similar between groups. After 12 months, change in FDG-PET uptake of the most diseased segment of the aorta was not different between atorvastatin and placebo, but technically adequate results comparing longitudinal changes in identical regions could be assessed in only 21 patients (atorvastatin Δ -0.03, 95% CI -0.17 to 0.12, vs placebo Δ -0.06, -0.25 to 0.13; p=0.77). Change in plaque could be assessed in all 37 people completing the study. Atorvastatin reduced non-calcified coronary plaque volume relative to placebo: median change -19.4% (IQR -39.2 to 9.3) versus 20.4% (-7.1 to 94.4; p=0.009, n=37). The number of high-risk plaques was significantly reduced in the atorvastatin group compared with the placebo group: change in number of low attenuation plaques -0.2 (95% CI -0.6 to 0.2) versus 0.4 (0.0, 0.7; p=0.03; n=37); and change in number of positively remodelled plaques -0.2 (-0.4 to 0.1) versus 0.4 (-0.1 to 0.8; p=0.04; n=37). Direct LDL-cholesterol (-1.00 mmol/L, 95% CI -1.38 to 0.61 vs 0.30 mmol/L, 0.04 to 0.55, p<0.0001) and lipoprotein-associated phospholipase A2 (-52.2 ng/mL, 95% CI -70.4 to -34.0, vs -13.3 ng/mL, -32.8 to 6.2; p=0.005; n=37) decreased significantly with atorvastatin relative to placebo. Statin therapy was well tolerated, with a low incidence of clinical adverse events.

Interpretation: No significant effects of statin therapy on arterial inflammation of the aorta were seen as measured by FDG-PET. However, statin therapy reduced non-calcified plaque volume and high-risk coronary plaque features in HIV-infected patients. Further studies should assess whether reduction in high-risk coronary artery disease translates into effective prevention of cardiovascular events in this at-risk population.

Funding: National Institutes of Health, Harvard Clinical and Translational Science Center, National Center for Research Resources.

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Effect of tesamorelin on visceral fat and liver fat in HIV-infected patients with abdominal fat accumulation: a randomized clinical trial

Stanley TL, Feldpausch MN, Oh J, Branch KL, Lee H, Torriani M, Grinspoon SK. Effect of tesamorelin on visceral fat and liver fat in HIV-infected patients with abdominal fat accumulation: a randomized clinical trial. JAMA. 2014 Jul 23-30;312(4):380-9. doi: 10.1001/jama.2014.8334. PMID: 25038357; PMCID: PMC4363137.


Importance: Among patients infected with human immunodeficiency virus (HIV), visceral adiposity is associated with metabolic dysregulation and ectopic fat accumulation. Tesamorelin, a growth hormone-releasing hormone analog, specifically targets visceral fat reduction but its effects on liver fat are unknown.

Objective: To investigate the effect of tesamorelin on visceral and liver fat.

Design, setting, and patients: Double-blind, randomized, placebo-controlled trial conducted among 50 antiretroviral-treated HIV-infected men and women with abdominal fat accumulation at Massachusetts General Hospital in Boston. The first patient was enrolled on January 10, 2011; for the final patient, the 6-month study visit was completed on September 6, 2013.

Interventions: Participants were randomized to receive tesamorelin, 2 mg (n=28), or placebo (n=22), subcutaneously daily for 6 months.

Main outcomes and measures: Primary end points were changes in visceral adipose tissue and liver fat. Secondary end points included glucose levels and other metabolic end points.

Results: Forty-eight patients received treatment with study drug. Tesamorelin significantly reduced visceral adipose tissue (mean change, -34 cm2 [95% CI, -53 to -15 cm2] with tesamorelin vs 8 cm2 [95% CI, -14 to 30 cm2] with placebo; treatment effect, -42 cm2 [95% CI, -71 to -14 cm2]; P = .005) and liver fat (median change in lipid to water percentage, -2.0% [interquartile range {IQR}, -6.4% to 0.1%] with tesamorelin vs 0.9% [IQR, -0.6% to 3.7%] with placebo; P = .003) over 6 months, for a net treatment effect of -2.9% in lipid to water percentage. Fasting glucose increased in the tesamorelin group at 2 weeks (mean change, 9 mg/dL [95% CI, 5-13 mg/dL] vs 2 mg/dL [95% CI, -3 to 8 mg/dL] in the placebo group; treatment effect, 7 mg/dL [95% CI, 1-14 mg/dL]; P = .03), but changes at 6 months in fasting glucose (mean change, 4 mg/dL [95% CI, -2 to 10 mg/dL] with tesamorelin vs 2 mg/dL [95% CI, -4 to 7 mg/dL] with placebo; treatment effect, 2 mg/dL [95% CI, -6 to 10 mg/dL]; P = .72 overall across time points) and 2-hour glucose (mean change, -1 mg/dL [95% CI, -18 to 15 mg/dL] vs -8 mg/dL [95% CI, -24 to 8 mg/dL], respectively; treatment effect, 7 mg/dL [95% CI, -16 to 29 mg/dL]; P = .53 overall across time points) were not significant.

Conclusions and relevance: In this preliminary study of HIV-infected patients with abdominal fat accumulation, tesamorelin administered for 6 months was associated with reductions in visceral fat and additionally with modest reductions in liver fat. Further studies are needed to determine the clinical importance and long-term consequences of these findings.

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Altered miRNA processing disrupts brown/white adipocyte determination and associates with lipodystrophy

Mori MA, Thomou T, Boucher J, Lee KY, Lallukka S, Kim JK, Torriani M, Yki-Järvinen H, Grinspoon SK, Cypess AM, Kahn CR. Altered miRNA processing disrupts brown/white adipocyte determination and associates with lipodystrophy. J Clin Invest. 2014 Aug;124(8):3339-51. doi: 10.1172/JCI73468. Epub 2014 Jul 1. PMID: 24983316; PMCID: PMC4109560.


miRNAs are important regulators of biological processes in many tissues, including the differentiation and function of brown and white adipocytes. The endoribonuclease dicer is a major component of the miRNA-processing pathway, and in adipose tissue, levels of dicer have been shown to decrease with age, increase with caloric restriction, and influence stress resistance. Here, we demonstrated that mice with a fat-specific KO of dicer develop a form of lipodystrophy that is characterized by loss of intra-abdominal and subcutaneous white fat, severe insulin resistance, and enlargement and "whitening" of interscapular brown fat. Additionally, KO of dicer in cultured brown preadipocytes promoted a white adipocyte-like phenotype and reduced expression of several miRNAs. Brown preadipocyte whitening was partially reversed by expression of miR-365, a miRNA known to promote brown fat differentiation; however, introduction of other miRNAs, including miR-346 and miR-362, also contributed to reversal of the loss of the dicer phenotype. Interestingly, fat samples from patients with HIV-related lipodystrophy exhibited a substantial downregulation of dicer mRNA expression. Together, these findings indicate the importance of miRNA processing in white and brown adipose tissue determination and provide a potential link between this process and HIV-related lipodystrophy.

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Growth hormone-releasing hormone in HIV-infected men with lipodystrophy: a randomized controlled trial

Koutkia P, Canavan B, Breu J, Torriani M, Kissko J, Grinspoon S. Growth hormone-releasing hormone in HIV-infected men with lipodystrophy: a randomized controlled trial. JAMA. 2004 Jul 14;292(2):210-8. doi: 10.1001/jama.292.2.210. PMID: 15249570.


Context: Reduced growth hormone (GH) concentrations are observed in men with human immunodeficiency virus (HIV) lipodystrophy.

Objective: To investigate the effects of growth hormone-releasing hormone (GHRH), a GH secretagogue, in treatment of HIV lipodystrophy.

Design, setting, and participants: Randomized, double-blind, placebo-controlled trial conducted at a research center in the United States between October 2002 and June 2003 and enrolling 31 HIV-infected men aged 18 to 60 years with evidence of lipodystrophy.

Interventions: Participants were assigned to receive GHRH (1 mg subcutaneously twice daily) or placebo for 12 weeks.

Main outcome measures: The primary outcome was change in concentrations of insulin-like growth factor 1 (IGF-1) to detect overall change in GH levels in response to GHRH. Secondary end points included body composition by dual-energy x-ray absorptiometry and computed tomography, lipodystrophy ratings, and levels of glucose, insulin, and lipids.

Results: Mean (SD) IGF-1 concentrations increased significantly in the GHRH group vs the placebo group (104 [110] ng/mL vs 6 [44] ng/mL, P =.004). Lean body mass significantly increased in the GHRH group vs the placebo group (0.9 [1.3] kg vs -0.3 [1.7] kg, P =.04), trunk fat significantly decreased (-0.4 [0.7] kg vs 0.2 [0.6] kg, P =.03), and the ratio of trunk to lower extremity fat improved significantly (-0.22 [0.32] vs 0.14 [0.29], P =.005). Abdominal visceral fat was reduced (-19.2 [36.6] cm2 vs 2.3 [24.3] cm2, P =.07) and the ratio of abdominal visceral fat to abdominal subcutaneous fat improved significantly more in the GHRH group (-0.19 [0.28] vs 0.07 [0.27], P =.02). Both physician and patient rating of lipodystrophy in the arms, legs, and abdomen also improved significantly. Levels of glucose, insulin, and lipids did not change significantly.

Conclusions: GHRH was well tolerated and effectively increased levels of IGF-1 in HIV-infected men with lipodystrophy. Total and regional body composition improved in response to GHRH, with increased lean mass and reduced truncal and visceral fat. Use of GHRH may potentially be a beneficial treatment strategy for this population.

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Metabolic effects of a growth hormone-releasing factor in patients with HIV

Falutz J, Allas S, Blot K, Potvin D, Kotler D, Somero M, Berger D, Brown S, Richmond G, Fessel J, Turner R, Grinspoon S. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007 Dec 6;357(23):2359-70. doi: 10.1056/NEJMoa072375. PMID: 18057338.


Background: Visceral adipose tissue accumulates during antiretroviral therapy in many patients who are infected with the human immunodeficiency virus (HIV); this process is associated with an increased cardiovascular risk. We assessed the use of a growth hormone-releasing factor analogue, tesamorelin, to decrease visceral adiposity.

Methods: We randomly assigned 412 patients with HIV (86% of whom were men) who had an accumulation of abdominal fat to receive a daily subcutaneous injection of either 2 mg of tesamorelin or placebo for 26 weeks. The primary end point was the percent change from baseline in visceral adipose tissue as shown on computed tomography. Secondary end points included triglyceride levels, the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol, the level of insulin-like growth factor I (IGF-I), and self-assessed body image. Glycemic measures included glucose and insulin levels.

Results: The measure of visceral adipose tissue decreased by 15.2% in the tesamorelin group and increased by 5.0% in the placebo group; the levels of triglycerides decreased by 50 mg per deciliter and increased by 9 mg per deciliter, respectively, and the ratio of total cholesterol to HDL cholesterol decreased by 0.31 and increased by 0.21, respectively (P<0.001 for all comparisons). Levels of total cholesterol and HDL cholesterol also improved significantly in the tesamorelin group. Levels of IGF-I increased by 81.0% in the tesamorelin group and decreased by 5.0% in the placebo group (P<0.001). Adverse events did not differ significantly between the two study groups, but more patients in the tesamorelin group withdrew from the study because of an adverse event. No significant differences were observed in glycemic measures.

Conclusions: Daily tesamorelin for 26 weeks decreased visceral fat and improved lipid profiles, effects that might be useful in HIV-infected patients who have treatment-associated central fat accumulation. (ClinicalTrials.gov number, NCT00123253 [ClinicalTrials.gov].).

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