Effects of lifestyle and associated diseases on serum CC16 suggest complex interactions among metabolism, heart and lungs

INTRODUCTION

Clara cell 16-kDa protein (CC16) is an anti-inflammatory, immunomodulatory secreted pulmonary protein with reduced serum concentrations in obesity according to recent data.

OBJECTIVE

Studies focused solely on bodyweight, which does not properly reflect obesity-associated implications of the metabolic and reno-cardio-vascular system. The purpose of this study was therefore to examine CC16 in a broad physiological context considering cardio-metabolic comorbidities of primary pulmonary diseases.

METHODS

CC16 was quantified in serum samples in a subset of the FoCus (N = 497) and two weight loss intervention cohorts (N = 99) using ELISA. Correlation and general linear regression analyses were applied to assess CC16 effects of lifestyle, gut microbiota, disease occurrence and treatment strategies. Importance and intercorrelation of determinants were validated using random forest algorithms.

RESULTS

CC16 A38G gene mutation, smoking and low microbial diversity significantly decreased CC16. Pre-menopausal female displayed lower CC16 compared to post-menopausal female and male participants. Biological age and uricosuric medications increased CC16 (all p < 0.01). Adjusted linear regression revealed CC16 lowering effects of high waist-to-hip ratio (est. -11.19 [-19.4; -2.97], p = 7.99 × 10-3), severe obesity (est. -2.58 [-4.33; -0.82], p = 4.14 × 10-3) and hypertension (est. -4.31 [-7.5; -1.12], p = 8.48 × 10-3). ACEi/ARB medication (p = 2.5 × 10-2) and chronic heart failure (est. 4.69 [1.37; 8.02], p = 5.91 × 10-3) presented increasing effects on CC16. Mild associations of CC16 were observed with blood pressure, HOMA-IR and NT-proBNP, but not manifest hyperlipidemia, type 2 diabetes, diet quality and dietary weight loss intervention.

CONCLUSION

A role of metabolic and cardiovascular abnormalities in the regulation of CC16 and its modifiability by behavioral and pharmacological interventions is indicated. Alterations by ACEi/ARB and uricosurics could point towards regulatory axes comprising the renin-angiotensin-aldosterone system and purine metabolism. Findings altogether strengthen the importance of interactions among metabolism, heart and lungs.

How can we assess "thrifty" and "spendthrift" phenotypes?

PURPOSE OF REVIEW

There is a large inter-individual variability in the magnitude of body weight change that cannot be fully explained by differences in daily energy intake and physical activity levels and that can be attributed to differences in energy metabolism. Measuring the short-term metabolic response to acute changes in energy intake can better uncover this inter-individual variability and quantify the degree of metabolic thriftiness that characterizes an individual's susceptibility to weight gain and resistance to weight loss. This review summarizes the methods used to identify the individual-specific metabolic phenotype (thrifty vs. spendthrift) in research and clinical settings.

RECENT FINDINGS

The metabolic responses to short-term fasting, protein-imbalanced overfeeding, and mild cold exposure constitute quantitative factors that characterize metabolic thriftiness.

SUMMARY

The energy expenditure response to prolonged fasting is considered the most accurate and reproducible measure of metabolic thriftiness, likely because the largest energy deficit best captures interindividual differences in the extent of metabolic slowing. However, all the other dietary/environmental challenges can be used to quantify the degree of thriftiness using whole-room indirect calorimetry. Efforts are underway to identify alternative methods to assess metabolic phenotypes in clinical and outpatient settings such as the hormonal response to low-protein meals.

The association between gut hormones and diet-induced metabolic flexibility in metabolically healthy adults

OBJECTIVE

This study investigated whether interindividual variance in diet-induced metabolic flexibility is explained by differences in gut hormone concentrations.

METHODS

A total of 69 healthy volunteers with normal glucose regulation underwent 24-hour assessments of respiratory quotient (RQ) in a whole-room indirect calorimeter during eucaloric feeding (EBL; 50% carbohydrate, 30% fat) and then, in a crossover design, during 24-hour fasting and three normal-protein (20%) overfeeding diets (200% energy requirements). Metabolic flexibility was defined as the change in 24-hour RQ from EBL during standard (50% carbohydrate), high-fat (60%), and high-carbohydrate (75%) overfeeding diets. Plasma concentrations of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) after an overnight fast were measured prior to and after each diet.

RESULTS

Compared with EBL, on average, 24-hour RQ decreased by ~4% during high-fat overfeeding, whereas it increased by ~4% during standard overfeeding and by ~9% during high-carbohydrate overfeeding. During high-carbohydrate overfeeding, but not during any other overfeeding diet or fasting, increased GLP-1 concentration was associated with increased RQ (r = 0.44, p < 0.001), higher/lower carbohydrate/lipid oxidation rates (r = 0.34 and r = -0.51, both p < 0.01), respectively, and increased plasma insulin concentration (r = 0.38, p = 0.02).

CONCLUSIONS

Increased GLP-1 concentration following high-carbohydrate overfeeding associated with a greater shift to carbohydrate oxidation, suggesting that GLP-1 may be implicated in diet-induced metabolic flexibility to carbohydrate overload.

Brief Research Report: Serum clara cell 16 kDa protein levels are increased in patients hospitalized for severe SARS-CoV-2 or sepsis infection

Background

Clara cell 16 kDa protein (CC16) is a secretory protein primarily expressed in epithelial cells in the lungs. Previous studies show that CC16 exerts anti-inflammatory and immune-modulatory properties in both acute and chronic pulmonary diseases. However, despite the evidence of CC16’s high biomarker potential, evaluation of its role in infectious diseases is yet very limited.

Methods

Serum CC16 concentrations were measured by ELISA and assessed in two different types of severe infections. Using a case-control study design, patients treated for either severe SARS-CoV-2 or severe non-pulmonary sepsis infection were compared to age- and sex-matched healthy human subjects.

Results

Serum CC16 was significantly increased in both types of infection (SARS-CoV-2: 96.22 ± 129.01 ng/ml vs. healthy controls: 14.05 ± 7.48 ng/ml, p = 0.022; sepsis: 35.37 ± 28.10 ng/ml vs. healthy controls: 15.25 ± 7.51 ng/ml, p = 0.032) but there were no distinct differences between infections with and without pulmonary focus (p = 0.089). Furthermore, CC16 serum levels were positively correlated to disease duration and inversely to the platelet count in severe SARS-CoV-2 infection.

Conclusions

Increased CC16 serum levels in both SARS-CoV-2 and sepsis reinforce the high potential as a biomarker for epithelial cell damage and bronchoalveolar−blood barrier leakage in pulmonary as well as non-pulmonary infectious diseases.

Effects of Short-term Fasting on Ghrelin/GH/IGF-1 Axis in Healthy Humans: The Role of Ghrelin in the Thrifty Phenotype

CONTEXT

A greater decrease in 24-hour energy expenditure (24hEE) during short-term fasting is indicative of a thrifty phenotype.

OBJECTIVE

As ghrelin and the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis are implicated in the regulation of energy intake and metabolism, we investigated whether ghrelin, GH, and IGF-1 concentrations mediate the fasting-induced decrease in 24hEE that characterizes thriftiness.

METHODS

In 47 healthy individuals, 24hEE was measured in a whole-room indirect calorimeter both during 24-hour eucaloric and fasting conditions. Plasma total ghrelin, GH, and IGF-1 concentrations were measured by enzyme-linked immunosorbent assay after an overnight fast the morning before and after each 24-hour session.

RESULTS

During 24-hour fasting, on average 24hEE decreased by 8.0% (P < .001), GH increased by ~5-fold (P < .001), whereas ghrelin (mean +23 pg/mL) and IGF-1 were unchanged (both P ≥ .19) despite a large interindividual variability in ghrelin change (SD 150 pg/mL). Greater fasting-induced increase in ghrelin was associated with a greater decrease in 24hEE during 24-hour fasting (r = -0.42, P = .003), such that individuals who increased ghrelin by 200 pg/mL showed an average decrease in 24hEE by 55 kcal/day.

CONCLUSION

Short-term fasting induced selective changes in the ghrelin/GH/IGF-1 axis, specifically a ghrelin-independent GH hypersecretion that did not translate into increased IGF-1 concentrations. Greater increase in ghrelin after 24-hour fasting was associated with greater decrease in 24hEE, indicating ghrelin as a novel biomarker of increased energy efficiency of the thrifty phenotype.

A dietary carbohydrate - gut Parasutterella - human fatty acid biosynthesis metabolic axis in obesity and type 2 diabetes

Recent rodent microbiome experiments suggest that besides Akkermansia, Parasutterella sp. are important in type 2 diabetes and obesity development. In the present translational human study, we aimed to characterize Parasutterella in our European cross-sectional FoCus cohort (n = 1,544) followed by validation of the major results in an independent Canadian cohort (n = 438). In addition, we examined Parasutterella abundance in response to a weight loss intervention (n = 55). Parasutterella was positively associated with BMI and type 2 diabetes independently of the reduced microbiome α/β diversity and low-grade inflammation commonly found in obesity. Nutritional analysis revealed a positive association with the dietary intake of carbohydrates but not with fat or protein consumption. Out of 126 serum metabolites differentially detectable by untargeted HPLC-based MS-metabolomics, L-cysteine showed the strongest reduction in subjects with high Parasutterella abundance. This is of interest, since Parasutterella is a known high L-cysteine consumer and L-cysteine is known to improve blood glucose levels in rodents. Furthermore, metabolic network enrichment analysis identified an association of high Parasutterella abundance with the activation of the human fatty acid biosynthesis pathway suggesting a mechanism for body weight gain. This is supported by a significant reduction of the Parasutterella abundance during our weight loss intervention. Together, these data indicate a role for Parasutterella in human type 2 diabetes and obesity, whereby the link to L-cysteine might be relevant in type 2 diabetes development and the link to the fatty acid biosynthesis pathway for body weight gain in response to a carbohydrate-rich diet in obesity development.

The size of apolipoprotein (a) is an independent determinant of the reduction in lipoprotein (a) induced by PCSK9 inhibitors

AIMS

Lipoprotein (a) [Lp(a)] is a lipoprotein species causatively associated with atherosclerosis. Unlike statins, PCSK9 inhibitors (PCSK9i) reduce Lp(a), but this reduction is highly variable. Levels of Lp(a) are chiefly governed by the size of its signature protein, apolipoprotein (a) [apo(a)]. Whether this parameter determines some of the reduction in Lp(a) induced by PCSK9i remains unknown. We aimed to investigate if the Lp(a) lowering efficacy of PCSK9i is modulated by the size of apo(a), which is genetically determined by the variable number of KIV domains present on that protein.

METHODS AND RESULTS

The levels of Lp(a) and the size of apo(a) were assessed in plasma samples from 268 patients before and after treatment with PCSK9i. Patients were recruited at the Outpatient Lipid Clinic of the Charité Hospital (Berlin) between 2015 and 2020. They were hypercholesterolemic at very high CVD risk with LDL-cholesterol levels above therapeutic targets despite maximally tolerated lipid-lowering therapy. Patients received either Alirocumab (75 or 150 mg) or Evolocumab (140 mg) every 2 weeks. Apo(a), apoB100, and apoE concentrations as well as apoE major isoforms were determined by liquid chromatography high-resolution mass spectrometry. Apo(a) isoforms sizes were determined by Western Blot. PCSK9i sharply reduced LDL-cholesterol (-57%), apoB100 (-47%) and Lp(a) (-36%). There was a positive correlation between the size of apo(a) and the relative reduction in Lp(a) induced by PCSK9i (r = 0.363, p = 0.0001). The strength of this association remained unaltered after adjustment for baseline Lp(a) levels and all other potential confounding factors. In patients with two detectable apo(a) isoforms, there was also a positive correlation between the size of apo(a) and the reduction in Lp(a), separately for the smaller (r = 0.350, p = 0.0001) and larger (r = 0.324, p = 0.0003) isoforms. The relative contribution of the larger isoform to the total concentration of apo(a) was reduced from 29% to 15% (p < 0.0001).

CONCLUSIONS

The size of apo(a) is an independent determinant of the response to PCSK9i. Each additional kringle domain is associated with a 3% additional reduction in Lp(a). This explains in part the variable efficacy of PCSK9i and allows to identify patients who will benefit most from these therapies in terms of Lp(a) lowering.

TRANSLATIONAL PERSPECTIVE

Unlike statins, PCSK9 inhibitors reduce the circulating levels of the highly atherogenic Lipoprotein (a). The underlying mechanism remains a matter of considerable debate. The size of apo(a), the signature protein of Lp(a), is extremely variable (300 to more than 800 kDa) and depends on its number of kringle domains. We now show that each increase in apo(a) size by one kringle domain is associated with a 3% additional reduction in Lp(a) following PCSK9i treatment and that apo(a) size polymorphism is an independent predictor of the reduction in Lp(a) induced by these drugs. In an era of personalized medicine, this allows to identify patients who will benefit most from PCSK9i in terms of Lp(a) lowering.

Reduced adaptive thermogenesis during acute protein-imbalanced overfeeding is a metabolic hallmark of the human thrifty phenotype

BACKGROUND

The human thrifty phenotype is characterized by a greater decrease in 24-h energy expenditure (24EE) during fasting due to relatively higher eucaloric 24EE in sedentary conditions, both of which are indicative of greater propensity to weight gain. Thriftiness is also associated with a smaller increase in 24EE (i.e., reduced adaptive thermogenesis) during overfeeding.

OBJECTIVES

We investigated whether short-term measures of adaptive thermogenesis during overfeeding with low/normal/high protein content characterize thriftiness.

METHODS

In this secondary cross-sectional analysis of a single-arm crossover study, 24EE was measured using whole-room indirect calorimetry during energy balance, fasting, and different overfeeding conditions (low/3% protein, high/30% protein, and 3 normal/20% protein diets) with 200% of eucaloric requirements in 77 healthy individuals [63 men; BMI (in kg/m2): 26.4 ± 4.3; body fat by DXA: 27.7% ± 9.4%, mean ± SD] with normal glucose regulation. Relations between the 24EE during energy balance (adjusted for body composition) and 24EE during each overfeeding diet were analyzed using separate linear regression models. Participants were arbitrarily categorized as thrifty/spendthrift based on the median value (-177 kcal/d) of the difference in 24EE between fasting and energy balance conditions.

RESULTS

Differences in 24EE during low/high-protein overfeeding diets (regression line slope = 0.76 and 0.68, respectively, both P < 0.05 compared with slope = 1) but not during the normal-protein overfeeding diets (all P > 0.05 compared with slope = 1) were dependent on baseline 24EE during energy balance. Specifically, individuals with higher eucaloric 24EE (thriftier phenotype) showed smaller increases in 24EE during protein-imbalanced overfeeding. Analyzed by group, thrifty individuals had smaller increases in 24EE by 42 and 237 kcal/d during low- and high-protein overfeeding, respectively, compared with spendthrift individuals who showed greater increases in 24EE by 100 and 302 kcal/d (P ≤ 0.03 compared with thrifty group).

CONCLUSIONS

During acute overfeeding conditions with low/high-protein content, thrifty participants have limited capacity to increase 24EE, indicating that impaired adaptive thermogenesis during protein-imbalanced diets further characterizes the thrifty phenotype and its susceptibility to weight gain. This trial was registered at clinicalTrials.gov as NCT00523627.

Higher fasting plasma FGF21 concentration is associated with lower ad libitum soda consumption in humans

BACKGROUND

The hepatokine fibroblast growth factor 21 (FGF21) influences eating behavior and sugar consumption in rodent models. However, whether circulating FGF21 concentration is associated with food and soda intake in humans is still unclear.

OBJECTIVE

We investigated whether fasting plasma FGF21 concentration is associated with objective measures of ad libitum food intake and soda consumption.

METHODS

Healthy individuals [n = 109; 69 men, aged 34 ± 10 y; BMI (kg/m2): 30.4 ± 7.7; body fat by DXA: 30.5% ± 8.9%] with available plasma for hormonal measurements participated in an inpatient cohort study to objectively quantify ad libitum food and soda intake for 3 d using an automated and reproducible vending machine paradigm. Fasting plasma FGF21 concentration was measured by ELISA prior to ad libitum feeding.

RESULTS

Fasting FGF21 concentration was inversely associated with daily soda intake (R = -0.22, P = 0.02 adjusted for demographics and anthropometrics), such that an interindividual difference of 200 pg/mL was associated with an average lower soda consumption by 68 kcal/d. Conversely, no associations were observed with total daily energy intake or macronutrient intake (all P > 0.17).

CONCLUSIONS

Higher plasma fasting FGF21 concentration is associated with lower ad libitum soda intake. Although this inverse correlation does not imply causation, the present results support the putative role of FGF21 in the reward pathways regulating sugar consumption in humans. This trial was registered at www.clinicaltrials.gov as NCT00342732.

Effect of various weight loss interventions on serum NT-proBNP concentration in severe obese subjects without clinical manifest heart failure

Obesity is associated with a “natriuretic handicap” indicated by reduced N-terminal fragment of proBNP (NT-proBNP) concentration. While gastric bypass surgery improves the natriuretic handicap, it is presently unclear if sleeve gastrectomy exhibits similar effects. We examined NT-proBNP serum concentration in n = 72 obese participants without heart failure before and 6 months after sleeve gastrectomy (n = 28), gastric bypass surgery (n = 19), and 3-month 800 kcal/day very-low calorie diet (n = 25). A significant weight loss was observed in all intervention groups. Within 6 months, NT-proBNP concentration tended to increase by a median of 44.3 pg/mL in the sleeve gastrectomy group (p = 0.07), while it remained unchanged in the other groups (all p ≥ 0.50). To gain insights into potential effectors, we additionally analyzed NT-proBNP serum concentration in n = 387 individuals with different metabolic phenotypes. Here, higher NT-proBNP levels were associated with lower nutritional fat and protein but not with carbohydrate intake. Of interest, NT-proBNP serum concentrations were inversely correlated with fasting glucose concentration in euglycemic individuals but not in individuals with prediabetes or type 2 diabetes. In conclusion, sleeve gastrectomy tended to increase NT-proBNP levels in obese individuals and might improve the obesity-associated “natriuretic handicap”. Thereby, nutritional fat and protein intake and the individual glucose homeostasis might be metabolic determinants of NT-proBNP serum concentration.

Urinary Dopamine Excretion Rate Decreases during Acute Dietary Protein Deprivation and Is Associated with Increased Plasma Pancreatic Polypeptide Concentration

Background: Dopamine, a key neurotransmitter in the autonomic nervous system participating in the homeostatic balance between sympathetic and parasympathetic divisions, is involved in food intake regulation. Objective: We investigated whether dopamine is altered by acute fasting or overfeeding diets with varying macronutrient content. Design: Ninety-nine healthy subjects underwent 24-h dietary interventions including eucaloric feeding, fasting, and five different overfeeding diets in a crossover design. Overfeeding diets (200% of eucaloric requirements) included one diet with 3%-protein (low-protein high-fat overfeeding-LPF: 46%-fat), three diets with 20%-protein, and a diet with 30%-protein (44%-fat). Urine was collected for 24 h and urinary dopamine concentration was quantified by high-performance liquid chromatography. Plasma pancreatic polypeptide (PP) concentration, an indirect marker of parasympathetic activity, was measured prior to and after each diet after an overnight fast. Results: During 24-h of fasting, dopamine decreased on average by ~14% compared to eucaloric conditions, whereas PP increased by two-fold (both p < 0.001). Lower dopamine during 24-h fasting correlated with increased PP (r = -0.40, p < 0.001). Similarly, on average urinary dopamine decreased during LPF by 14% (p < 0.001) and lower dopamine correlated with increased PP (r = -0.31, p = 0.01). No changes in dopamine and PP concentrations were observed during other overfeeding diets (all p > 0.05). Conclusions: Dopamine concentrations decrease during short-term fasting and overfeeding with a low-protein diet. As both dietary conditions have in common protein deficit, the correlation between dopamine and PP suggests a compensatory mechanism underlying the shift from sympathetic to parasympathetic drive during dietary protein deprivation.

Reduced brown adipose tissue activity during cold exposure is a metabolic feature of the human thrifty phenotype

BACKGROUND

We recently demonstrated that thrifty subjects, characterized by a greater decrease in 24 h energy expenditure (24hEE) during short-term fasting, have less capacity for cold-induced thermogenesis (CIT) during 24 h of mild cold exposure.

OBJECTIVE

As cold-induced brown adipose tissue activation (CIBA) is a determinant of CIT, we sought to investigate whether thrifty individuals also have reduced CIBA.

METHODS

Twenty-four healthy subjects (age: 29.8 ± 9.5y, body fat: 27.3 ± 12.4%, 63% male) were admitted to our clinical research unit and underwent two 24hEE assessments in a whole-room indirect calorimeter during energy balance and fasting conditions at thermoneutrality to quantify their degree of thriftiness. Positron emission tomography/computed tomography scans were performed after exposure to 16 °C for 2 h to quantify peak CIBA.

RESULTS

A greater decrease in 24hEE during fasting was associated with lower peak CIBA (r = 0.50, p = 0.01), such that a 100 kcal/day greater reduction in 24hEE related to an average 3.2 g/mL lower peak CIBA.

CONCLUSION

Our results indicate that reduced CIBA is a metabolic trait of the thrifty phenotype which might explain reduced CIT capacity and greater predisposition towards weight gain in individuals with a thrifty metabolism.

Gliflozins for the Treatment of Congestive Heart Failure and Renal Failure in Type 2 Diabetes

BACKGROUND

Gliflozins are effective drugs for the treatment of type 2 diabetes. They inhibit sodium glucose cotransporter 2 in the proximal renal tubule, leading to increased glucose excretion. On the basis of findings from relevant studies, gliflozins are also increasingly used in clinical practice to treat congestive heart failure and renal failure.

METHODS

This review is based on pertinent publications retrieved from a selective literature search in PubMed and GoogleScholar.

RESULTS

Cardiovascular safety studies revealed early on that gliflozins can lower the hospitalization rate of patients suffering from congestive heart failure with a reduced leftventricular ejection fraction (HFrEF). They also showed favorable effects on multiple renal endpoints. In recent years, studies such as DAPA-HF and CREDENCE have further documented the benefit of gliflozins in the treatment of congestive heart failure and renal failure in patients with type 2 diabetes, and gliflozins have accordingly been incorporated into the pertinent guidelines. In the recently published EMPEROR-Reduced trial, empagliflozin was found to significantly lower the frequency of a combined cardiovascular endpoint in patients with HFrEF (19.4 % versus 24.7%; hazard ratio [HR] 0.75; 95% confidence interval [0.65; 0.86]; number needed to treat [NNT] 19, p <0.001). In the DAPA-CKD trial, which was also recently published, dapagliflozin was found to significantly lower the frequency of a combined renal endpoint (9.2% versus 14.5%; HR 0.61 [0.51; 0.72]; NNT 19; p <0.001).

CONCLUSION

On the basis of findings from specific studies, gliflozins will henceforth be a major class of drug for the treatment of HFrEF and renal failure, independently of the presence of type 2 diabetes.

Circulating sDPP-4 is Increased in Obesity and Insulin Resistance but Is Not Related to Systemic Metabolic Inflammation

CONTEXT

Dipeptidylpeptidase (DPP)-4 is a key regulator of the incretin system. It exists in a membrane-bound form and a soluble form (sDPP-4). Initial human studies suggested sDPP-4 to be an adipokine involved in metabolic inflammation. However, recent mechanistic data in genetically modified mice has questioned these findings.

OBJECTIVES

We examined circulating sDPP-4 in a cohort of n = 451 humans with different metabolic phenotypes and during 3 different weight loss interventions (n = 101) to further clarify its role in human physiology and metabolic diseases.

DESIGN

sDPP-4 serum concentrations were measured by enzyme-linked immunosorbent assay and related to several phenotyping data including gut microbiome analysis.

RESULTS

sDPP-4 increased with age and body weight and was positively associated with insulin resistance and hypertriglyceridemia but was reduced in manifest type 2 diabetes. In addition, we found reduced serum concentrations of sDPP-4 in subjects with arterial hypertension. In contrast to earlier reports, we did not identify an association with systemic markers of inflammation. Impaired kidney and liver functions significantly altered sDPP-4 concentrations while no relation to biomarkers for heart failure was observed. Having found increased levels of sDPP-4 in obesity, we studied surgical (gastric bypass and sleeve gastrectomy) and nonsurgical interventions, revealing a significant association of sDPP-4 with improvement of liver function tests but not with changes in body weight.

CONCLUSIONS

Our data suggest that sDPP-4 is related to hepatic abnormalities in obesity rather than primarily functioning as an adipokine and that sDPP-4 is implicated both in glucose and in lipid metabolism, but not fundamentally in systemic inflammation.

Reduced metabolic efficiency in sedentary eucaloric conditions predicts greater weight regain in adults with obesity following sustained weight loss

Background

Successful long-term weight loss maintenance after caloric restriction (CR) is rarely achieved. Besides known metabolic, behavioral, and cognitive factors, 24-hour energy expenditure (24hEE) relative to body size (i.e., metabolic efficiency) might influence subsequent weight loss maintenance.

Methods

Eleven participants with obesity (BMI=39.0±8.7 kg/m², body fat=36.1±6.4%) had 24hEE measured in a whole-room indirect calorimeter during eucaloric conditions and weight stability prior to starting a 6-week inpatient CR study (50% of daily energy needs). Twenty-four-hour energy expenditure was adjusted via regression analysis for fat free mass (FFM) and fat mass (FM) by DXA. Body composition was reassessed at the end of CR and after 1-year follow-up. Free-living weight was assessed by monthly weight measurements during 12 months.

Results

After 6-week CR, participants lost 8.5±2.7% weight (FFM: −6.3±3.6 kg, FM: −3.4±1.2 kg) but regained 5.1±8.0% one year following CR, which was mostly due to FFM regain (+5.7±5.5 kg) and unchanged FM. A relatively higher 24hEE by 100 kcal/day prior to CR was associated with an average greater rate of weight regain by +0.3 kg/month during follow-up and a greater final weight regain by +5.1 kg after 1 year of follow-up.

Conclusion

These results suggest that reduced metabolic efficiency in 24hEE during eucaloric, sedentary conditions may predict greater weight regain after CR-induced weight loss.

Reduced Albumin Concentration Predicts Weight Gain and Higher Ad Libitum Energy Intake in Humans

OBJECTIVE

Circulating albumin is negatively associated with adiposity but whether it is associated with increased energy intake, lower energy expenditure or weight gain has not been examined.

METHODS

In study 1 (n=238; 146 men), we evaluated whether fasting albumin concentration was associated with 24-h energy expenditure and ad libitum energy intake. In study 2 (n=325;167 men), we evaluated the association between plasma albumin and change in weight and body composition.

RESULTS

After adjustment for known determinants of energy intake lower plasma albumin concentration was associated with greater total daily energy intake (β= 89.8 kcal/day per 0.1 g/dl difference in plasma albumin, p=0.0047). No associations were observed between plasma albumin concentrations and 24-h energy expenditure or 24-h respiratory quotient (p>0.2). Over 6 years, volunteers gained on average 7.5 ± 11.7 kg (p<0.0001). Lower albumin concentrations were associated with greater weight [β=3.53 kg, p=0.039 (adjusted for age, sex, follow up time), CI 0.16 to 6.21 per 1 g/dl difference albumin concentration] and fat mass (β=2.3 kg, p=0.022), respectively, but not with changes in fat free mass (p=0.06).

CONCLUSIONS

Lower albumin concentrations were associated with increased ad libitum food intake and weight gain, indicating albumin as a marker of energy intake regulation.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifiers NCT00340132, NCT00342732.

Procedures for Measuring Excreted and Ingested Calories to Assess Nutrient Absorption Using Bomb Calorimetry

OBJECTIVE

With the upsurge in interest in the gut microbiome, complete and accurate measurement of ingested calories and calories lost through excreted stool is crucial for assessing the effect of the microbiota on nutrient absorption.

METHODS

Measurement of ingested and excreted calories was conducted over 3 days. Meals were made in duplicate: one was given to the participant, and one was used for the measurement of calories. Stool was marked by nonabsorbable dye ingested prior to and at the end of each 3-day diet period and was collected for caloric assessment from the appearance of the first dye marker until the appearance of the second dye marker.

RESULTS

Stool calories per gram for pellets were 4.91 ± 0.06 kcal/g. The mean stool calorie loss as a percentage of ingested calories was 7.3% ± 1.6% (range, 6.6%-8.5%). The stool measurement of kilocalories per gram was not associated with the total measured stool calories or with stool weight (P = 0.2 and P = 0.2, respectively) over the 3-day period. However, the weight of stool samples during each dietary intervention was positively associated with the calorie loss in stool (r = 0.58, P < 0.0001).

CONCLUSIONS

Our methods provide a direct measure of ingested calories and stool calories needed to accurately assess relative stool calorie loss as a measure of nutrient absorption. The weight of stool samples across the marked diet period is crucial to determining total stool calories.

Autoantibody-negative insulin-dependent diabetes mellitus after SARS-CoV-2 infection: a case report

Here we report a case where the manifestations of insulin-dependent diabetes occurred following SARS-CoV-2 infection in a young individual in the absence of autoantibodies typical for type 1 diabetes mellitus. Specifically, a 19-year-old white male presented at our emergency department with diabetic ketoacidosis, C-peptide level of 0.62 µg l^-1, blood glucose concentration of 30.6 mmol l^-1 (552 mg dl^-1) and haemoglobin A1c of 16.8%. The patient´s case history revealed probable COVID-19 infection 5-7 weeks before admission, based on a positive test for antibodies against SARS-CoV-2 proteins as determined by enzyme-linked immunosorbent assay. Interestingly, the patient carried a human leukocyte antigen genotype (HLA DR1-DR3-DQ2) considered to provide only a slightly elevated risk of developing autoimmune type 1 diabetes mellitus. However, as noted, no serum autoantibodies were observed against islet cells, glutamic acid decarboxylase, tyrosine phosphatase, insulin and zinc-transporter 8. Although our report cannot fully establish causality between COVID-19 and the development of diabetes in this patient, considering that SARS-CoV-2 entry receptors, including angiotensin-converting enzyme 2, are expressed on pancreatic β-cells and, given the circumstances of this case, we suggest that SARS-CoV-2 infection, or COVID-19, might negatively affect pancreatic function, perhaps through direct cytolytic effects of the virus on β-cells.

Circulating levels of soluble Dipeptidylpeptidase-4 are reduced in human subjects hospitalized for severe COVID-19 infections

Dipeptidylpeptidase (DPP)-4 is a key regulator of the incretin system. For several years DPP-4 inhibitors in addition to GLP-1 analogues are of major importance in the clinical management of obesity and type 2 diabetes. DPP-4 is also known as CD26 and represents a membrane bound protease on the surface of several eukaryotic cell types. Of interest, DPP-4, like ACE2, has been shown to serve as a binding partner for corona-like viruses to enter host immune cells. Since metabolic diseases are major risk factors for the present COVID-19 pandemic, we examined circulating soluble DPP-4 serum concentrations in patients suffering from severe COVID-19 infection and in healthy human subjects in a case control design. In this analysis sDPP-4 levels were significantly lower in COVID-19 patients compared to controls (242.70 ± 202.12 ng/mL versus 497.70 ± 188.13 ng/mL, p = 0.02). We also examined sDPP-4 serum concentrations in patients suffering from sepsis not due to corona-like viruses. In these subjects, sDPP-4 levels were not different compared to healthy case controls (p = 0.14), which might suggest the decrease of sDPP-4 to be specific for corona-like virus infections. Currently, most data point towards membrane bound ACE2 in contrast to DPP-4 as the major binding partner for COVID-19 internalization into host immune cells. However, the finding that the circulating soluble form of DPP-4 is reduced in hospitalized patients might suggest a regulatory role for both, ACE and DPP-4, in COVID-19 infections, especially since obesity and type 2 diabetes are major risk factor for a severe course of the disease

Early adaptive thermogenesis is a determinant of weight loss after six weeks of caloric restriction in overweight subjects

BACKGROUND

Adaptive thermogenesis during prolonged energy deficit refers to the greater than expected reduction in energy expenditure (EE) independent of concomitant loss of metabolically active body mass.

OBJECTIVE

As inter-individual variability in the magnitude of adaptive thermogenesis may influence the extent of energy deficit thereby predicting the amount of weight reduction, we investigated whether early adaptive thermogenesis is a determinant of weight loss after 6 weeks of daily 50% caloric restriction in an inpatient setting.

DESIGN AND METHODS

The current study reports the results of an exploratory, secondary analysis in overweight but otherwise healthy subjects (n = 11, 7 men, 35 ± 9y, BMI = 40 ± 7 kg/m², body fat = 63.3 ± 5.3%). Body composition and 24-h EE (24hEE) measurement in a whole-room indirect calorimeter were used to calculate the magnitude of adaptive thermogenesis while on caloric restriction after 1, 3 and 6 weeks. Energy deficit during caloric restriction was quantified via food, stool, and urine bomb calorimetry. Fasting hormonal concentrations (FT4, FT3, FGF21, leptin) were obtained at baseline and at weeks 3 and 6 during caloric restriction.

RESULTS

The magnitude of adaptive thermogenesis in 24hEE after 1 week of caloric restriction was -178 ± 137 kcal/day (mean ± SD), was overall stable during and following caloric restriction, and demonstrated remarkable intra-individual consistency. A relatively greater decrease in 24hEE of 100 kcal/d after 1 week of caloric restriction was associated on average with reduced energy deficit by 8195 kcal over 6 weeks and predicted 2.0 kg less weight loss, of which 0.5 kg was fat mass, after 6 weeks. No correlations were found between hormonal concentrations and weight loss.

CONCLUSIONS

The extent of weight loss is influenced by the magnitude of adaptive thermogenesis in the early stage of caloric restriction. Although these results need replication in larger study groups with adequate statistical power, targeting adaptive thermogenesis may help to optimize long-term interventions in obesity therapy.

Metabolic Responses to 24-Hour Fasting and Mild Cold Exposure in Overweight Individuals Are Correlated and Accompanied by Changes in FGF21 Concentration

A greater decrease in 24-h energy expenditure (24 EE) during 24-h fasting defines a "thriftier" metabolic phenotype prone to weight gain during overfeeding and resistant to weight loss during caloric restriction. As the thermogenic response to mild cold exposure (COLD) may similarly characterize this human phenotype identified by acute fasting conditions, we analyzed changes in 24 EE and sleeping metabolic rate (SLEEP) in a whole-room indirect calorimeter during 24-h fasting at thermoneutrality (24°C) and during energy balance both at thermoneutrality (24°C) and mild cold (19°C) in 20 healthy volunteers (80% male; aged 36.6 ± 11.4 years; percentage body fat 34.8 ± 10.5%). Greater decrease in 24 EE during fasting (thriftier phenotype) was associated with less increase in 24 EE during COLD (i.e., less cold-induced thermogenesis). Greater decreases in plasma fibroblast growth factor 21 (FGF21) after 24-h fasting and after COLD were highly correlated and associated with greater decreases in SLEEP in both conditions. We conclude that the metabolic responses to short-term fasting and COLD are associated with and mediated by the liver-derived hormone FGF21. Thus, the 24 EE response to COLD further identifies the "thrifty" versus "spendthrift" phenotype, providing an additional setting to investigate the physiological mechanisms underlying the human metabolic phenotype and characterizing the individual susceptibility to weight change.

Akte AIDS 2020: „Gesund bleiben mit HIV“

Unser Motto versammelt Fachbeiträge zu Komorbiditäten und zur Vorsorge bei HIV-Infizierten. Das Großthema COVID-19-Pandemie konnte bei der Planung dieser „Akte AIDS“ zwar noch niemand absehen, doch spüren wir der Frage, ob HIV hier einen Risikofaktor darstellt, in aktuellen Beiträgen nach.

Metabolic Factors Determining the Susceptibility to Weight Gain: Current Evidence

PURPOSE OF REVIEW

There is substantial inter-individual variability in body weight change, which is not fully accounted by differences in daily energy intake and physical activity levels. The metabolic responses to short-term perturbations in energy intake can explain part of this variability by quantifying the degree of metabolic "thriftiness" that confers more susceptibility to weight gain and more resistance to weight loss. It is unclear which metabolic factors and pathways determine this human "thrifty" phenotype. This review will investigate and summarize emerging research in the field of energy metabolism and highlight important metabolic mechanisms implicated in body weight regulation in humans.

RECENT FINDINGS

Dysfunctional adipose tissue lipolysis, reduced brown adipose tissue activity, blunted fibroblast growth factor 21 secretion in response to low-protein hypercaloric diets, and impaired sympathetic nervous system activity might constitute important metabolic factors characterizing "thriftiness" and favoring weight gain in humans. The individual propensity to weight gain in the current obesogenic environment could be ascertained by measuring specific metabolic factors which might open up new pathways to prevent and treat human obesity.

Recharacterizing the Metabolic State of Energy Balance in Thrifty and Spendthrift Phenotypes

PURPOSE

The human thrifty phenotype hypothesis presupposes that lower 24-hour (24h) energy expenditure (24EE) during famine preserves body mass and promotes survival. The prevailing view defines thrifty individuals as having a lower 24EE during fasting. However, it is also plausible that the greater decline in 24EE during fasting in thrifty individuals is due to higher 24EE during energy balance conditions (ENBAL). Herein, we provide evidence that this is indeed the case.

METHODS

In 108 healthy subjects, 24EE was measured in a whole-room indirect calorimeter both during ENBAL and 24h fasting conditions. Subjects were categorized as thrifty or spendthrift based on the median value (-162 kcal/day) of the difference in 24EE (adjusted for body composition) between fasting and ENBAL conditions. Concomitant 24h urinary catecholamines were assessed by liquid chromatography-mass spectrometry.

RESULTS

Compared to ENBAL, 24EE decreased during 24h fasting by 172 kcal/day (standard deviation = 93; range, -470 to 122). A greater-than-median decrease in 24EE ("thriftier" phenotype) was due to higher 24EE during ENBAL (+124 kcal/day; P < 0.0001) but not to lower 24EE during fasting (P = 0.35). Greater fasting-induced increase in epinephrine was associated with concomitant lower decrease in 24EE (r = 0.27; P = 0.006).

MAIN CONCLUSION

The greater decrease in 24EE during acute fasting (which characterizes the thrifty phenotype) is not due to reduced metabolic rate during fasting but to a relatively higher 24EE during feeding conditions, and this decrease in 24EE during fasting is accompanied by a smaller increase in epinephrine. These results recharacterize the prevailing view of the short-term 24EE responses that define the human metabolic phenotypes. Clinical Trials: NCT00523627, NCT00687115, NCT02939404.

Higher Urinary Dopamine Concentration is Associated with Greater Ad Libitum Energy Intake in Humans

OBJECTIVE

This study aimed to assess the relationship between dopamine, a neurotransmitter involved in feeding behavior, and ad libitum energy intake in humans.

METHODS

Healthy individuals (n = 158; 72 Native American, 50 white, 18 black, and 18 Hispanic participants; BMI: 33 [SD 9] kg/m² ; body fat: 33% [SD 9%]) were admitted for two inpatient studies investigating the determinants of ad libitum energy intake and assessed for 3 days using a highly reproducible, computerized vending machine paradigm. Urine was collected for 24 hours during eucaloric conditions prior to the ad libitum feeding period, and urinary dopamine excretion rate was quantified by high-performance liquid chromatography.

RESULTS

Urinary dopamine excretion rate was on average 346 ± 106 μg over 24 hours and was positively correlated with BMI (r = 0.28, P < 0.0001). Higher dopamine concentrations were associated with lower cognitive restraint (ρ = -0.25, P = 0.005) and greater total ad libitum energy intake (r = 0.29, P = 0.0002). However, after adjustment for anthropometrics, in black and white cohorts, higher dopamine concentrations were associated with greater total ad libitum energy intake (r = 0.70, P = 0.001 and r = 0.33, P = 0.02, respectively), whereas no associations were observed in Native American or Hispanic cohorts (all P > 0.3).

CONCLUSIONS

Higher urinary dopamine concentrations are associated with greater ad libitum energy intake, indicating a role for dopamine in the reward pathway regulating human feeding behavior.

Urinary Norepinephrine Is a Metabolic Determinant of 24-Hour Energy Expenditure and Sleeping Metabolic Rate in Adult Humans

BACKGROUND

Interindividual variability in 24-hour energy expenditure (24EE) during energy-balance conditions is mainly determined by differences in body composition and demographic factors. Previous studies suggested that 24EE might also be influenced by sympathetic nervous system activity via catecholamine (norepinephrine, epinephrine) secretion. Therefore, we analyzed the association between catecholamines and energy expenditure in 202 individuals from a heterogeneous population of mixed ethnicities.

METHODS

Participants (n = 202, 33% female, 14% black, 32% white, 41% Native American, 11% Hispanic, age: 36.9 ± 10.3 y [mean ± SD], percentage body fat: 30.3 ± 9.4) resided in a whole-room calorimeter over 24 hours during carefully controlled energy-balance conditions to measure 24EE and its components: sleeping metabolic rate (SMR), awake-fed thermogenesis (AFT), and spontaneous physical activity (SPA). Urine samples were collected, and 24-h urinary epinephrine and norepinephrine excretion rates were assessed by high-performance liquid chromatography.

RESULTS

Both catecholamines were associated with 24EE and SMR (norepinephrine: +27 and +19 kcal/d per 10 μg/24h; epinephrine: +18 and +10 kcal/d per 1 μg/24h) in separate analyses after adjustment for age, sex, ethnicity, fat mass, fat-free mass, calorimeter room, temperature, and physical activity. In a multivariate model including both norepinephrine and epinephrine, only norepinephrine was independently associated with both 24EE and SMR (both P < .008), whereas epinephrine became insignificant. Neither epinephrine nor norepinephrine were associated with adjusted AFT (both P = .37) but epinephrine was associated with adjusted SPA (+0.5% per 1 μg/24h).

CONCLUSIONS

Our data provide compelling evidence that sympathetic nervous system activity, mediated via norepinephrine, is a determinant of human energy expenditure during nonstressed, eucaloric conditions.

Impaired Metabolic Flexibility to High-Fat Overfeeding Predicts Future Weight Gain in Healthy Adults

The ability to switch fuels for oxidation in response to changes in macronutrient composition of diet (metabolic flexibility) may be informative of individuals' susceptibility to weight gain. Seventy-nine healthy, weight-stable participants underwent 24-h assessments of energy expenditure and respiratory quotient (RQ) in a whole-room calorimeter during energy balance (EBL) (50% carbohydrate, 30% fat) and then during 24-h fasting and three 200% overfeeding diets in a crossover design. Metabolic flexibility was defined as the change in 24-h RQ from EBL during fasting and standard overfeeding (STOF) (50% carbohydrate, 30% fat), high-fat overfeeding (HFOF) (60% fat, 20% carbohydrate), and high-carbohydrate overfeeding (HCOF) (75% carbohydrate, 5% fat) diets. Free-living weight change was assessed after 6 and 12 months. Compared with EBL, RQ decreased on average by 9% during fasting and by 4% during HFOF but increased by 4% during STOF and by 8% during HCOF. A smaller decrease in RQ, reflecting a smaller increase in lipid oxidation rate, during HFOF but not during the other diets predicted greater weight gain at both 6 and 12 months. An impaired metabolic flexibility to acute HFOF can identify individuals prone to weight gain, indicating that an individual's capacity to oxidize dietary fat is a metabolic determinant of weight change.

Clinical outcome of a patient with lysosomal acid lipase deficiency and first results after initiation of treatment with Sebelipase alfa: A case report

We report on a case of very rare autosomal recessive cholesteryl ester storage disease due to lysosomal acid lipase deficiency (LALD). LALD is caused by mutations in the lysosomal acid lipase A (LIPA) gene resulting in cholesteryl ester accumulation in liver, spleen, and macrophages. It can lead to liver failure, accelerated atherosclerosis and premature death. Until recently, treatment options were limited to lipid-lowering medications to control dyslipidemia. Presently, a long-term enzyme replacement therapy with Sebelipase alfa, a recombinant human lysosomal acid lipase, is available for patients with LALD. Our patient's condition became conspicuous at the age of two due to a xanthogranuloma of the chin together with increased lipid levels, elevated liver enzymes and hepatomegaly. It took another five years until our patient was diagnosed with LALD after genetic testing. A bi-weekly therapy with intravenous Sebelipase alfa was started at the age of 26 years. It led to normalization of lipid levels, reduction of liver enzymes and beginning regression of hepatomegaly in the absence of adverse drug reactions after 46 infusions. Since LALD can take a fatal course even in patients with a long-term stable condition, it is essential to identify affected patients early and to treat them appropriately by enzyme replacement therapy. LALD should be suspected in patients with low high-density lipoprotein cholesterol (HDL-C) and high low-density lipoprotein cholesterol (LDL-C) in conjunction with elevated liver enzymes or hepatomegaly. A registry for LALD patients shall help to advance our understanding of the disease as well as improve patient care (NCT01633489).

Metabolic response to fasting predicts weight gain during low-protein overfeeding in lean men: further evidence for spendthrift and thrifty metabolic phenotypes

BACKGROUND

Greater increase in 24-h energy expenditure (24EE) during overfeeding and smaller decrease in 24EE during fasting ("spendthrift" metabolic phenotype) are associated with more weight loss during sustained caloric restriction in overweight subjects.

OBJECTIVES

The aim of this study was to investigate whether these acute metabolic responses can also predict weight gain during sustained overfeeding in lean individuals.

METHODS

Seven lean men participated in this study. Prior to overfeeding, 24EE responses to fasting and 200% normal-protein overfeeding were measured in a whole-room indirect calorimeter. Volunteers underwent 6 wk of 150% low-protein (2%) overfeeding followed by another wk of weight-maintaining diet, during which 24EE was revaluated. Body composition, 24EE, and various hormone concentrations, including fibroblast growth factor 21 (FGF21), were assessed at baseline, at wk 1, 3, and 6 of the overfeeding period, and 1 wk following overfeeding through the use of dual-energy X-ray absorptiometry, indirect calorimetry, and ELISA. Cumulative energy surplus was calculated from 24EE, daily physical activity, and direct measurements of calories of nutrient intake, feces, and urine by bomb calorimetry.

RESULTS

The average weight gain during 6 wk of low-protein overfeeding was 3.8 kg (6.1%, min: +2.5%, max: +8.0%). During 24-h fasting at baseline, 24EE decreased on average (mean ± SD) by 158 ± 81 kcal/d (P = 0.007). Subjects with less 24EE decrease during fasting (more metabolically spendthrift individuals) gained less weight (r = -0.84, P = 0.03), less fat mass (r = -0.81, P = 0.049), and stored less calories (r = -0.91, P = 0.03) during overfeeding. Following overfeeding, increased 24EE above requirements for achieved body size was associated with less weight and fat mass gain (r = -0.78, P = 0.04) and with the increase in 24EE during 200% normal-protein overfeeding measured at baseline (r = 0.91, P = 0.005). Serum FGF21 concentrations increased up to 44-fold during overfeeding (P <  0.0001).

CONCLUSIONS

Low-protein overfeeding may be an important tool to identify metabolic phenotypes (spendthrift compared with thrifty) that characterize susceptibility to weight gain. This trial was registered at clinicaltrials.gov as NCT00687115.

Effects of Short-Term Fasting and Different Overfeeding Diets on Thyroid Hormones in Healthy Humans

Background: A greater decrease in 24-hour energy expenditure (EE) during fasting and a smaller increase in 24-hour EE during low-protein overfeeding (metabolic "thrifty" phenotype) predict weight gain. As thyroid hormones (TH) are implicated in energy intake and metabolism, we assessed whether: (i) TH concentrations are altered by 24-hour fasting or overfeeding diets with varying protein content and (ii) diet-related changes in TH correlate with concomitant changes in EE. Methods: Fifty-eight euthyroid healthy subjects with normal glucose regulation underwent 24-hour dietary interventions including fasting, eucaloric feeding, and five overfeeding diets in a crossover design within a whole-room indirect calorimeter to measure the 24-hour EE. Overfeeding diets (200% of energy requirements) included three diets with 20% protein, one diet with 3% protein (low-protein overfeeding diet [LPF]: 46% fat), and one diet with 30% protein (high-protein overfeeding diet [HPF]: 44% fat, n = 51). Plasma free thyroxine (fT4), free triiodothyronine (fT3), and fibroblast growth factor 21 (FGF21) concentrations were measured after overnight fast the morning of and after each diet. Results: On average, fT4 increased by 8% (+0.10 ng/dL, 95% confidence interval [CI 0.07-0.13], p < 0.0001) and fT3 decreased by 6% (-0.17 pg/mL [CI -0.27 to -0.07], p = 0.001) after 24-hour fasting, whereas both fT4 and fT3 decreased by 5% (-0.07 ng/dL [CI -0.11 to -0.04], p < 0.0001) and 4% (-0.14 pg/mL [CI -0.24 to -0.04], p = 0.008) following HPF, respectively. Greater decreases in fT3 after HPF are associated with larger decreases in FGF21 (r = 0.40, p = 0.005). Following LPF, the mean fT3 increased by 6% (+0.14 pg/mL [CI 0.05-0.2], p = 0.003) with no change in fT4 (p = 0.7). No changes in TH were observed after normal-protein overfeeding diets (all p > 0.1). No associations were observed between TH concentrations and diet-related changes in 24-hour EE during any diet (all p > 0.07). Conclusions: Acute (200%) short-term (24 hours) changes in food intake induce small changes in TH concentrations only after diets with low (0% fasting and 3% protein overfeeding) or high (30% protein overfeeding) protein content. The fT3-FGF21 association after high-protein overfeeding suggests a role for TH in inhibiting FGF21 secretion by the liver during protein excess. These results indicate that TH are involved in protein metabolism; however, they do not mediate the short-term EE response to diets that characterize the metabolic phenotypes and determine the individual susceptibility to weight gain.

Gene Therapy in Lipoprotein Lipase Deficiency: Case Report on the First Patient Treated with Alipogene Tiparvovec Under Daily Practice Conditions

One-year results are reported of the first lipoprotein lipase deficiency (LPLD) patient treated with alipogene tiparvovec, which is indicated for the treatment of patients with genetically confirmed LPLD suffering from acute and recurrent pancreatitis attacks (PAs) despite dietary restrictions and expressing >5% of lipoprotein lipase (LPL) mass compared to a healthy control. During clinical development, alipogene tiparvovec has shown improvement of chylomicron metabolism and reduction of pancreatitis incidence up to 5.8 years post treatment. A 43-year-old female presented with severe hypertriglyceridemia (median triglyceride [TG] value of 3,465 mg/dL) and a history of 37 PAs within the last 25 years, despite treatment with fibrates, omega 3 fatty acids, and-since 2012-twice-weekly lipid apheresis. LPLD was confirmed by identification of two different pathogenic variants in the LPL gene located on separate alleles and therefore constituting a compound heterozygous state. With a detectable LPL mass level of 55.1 ng/mL, the patient was eligible for alipogene tiparvovec treatment, and in September 2015, she receved 40 injections (1 × 10¹² genome copies/kg) in the muscles of her upper legs under epidural anesthesia and immunosuppressive therapy. Alipogene tiparvovec was well tolerated: no injection site or systemic reactions were observed. Median TG values decreased by 52%, dropping to 997 mg/dL at month 3 and increasing thereafter. Within the first 18 months post treatment, the patient discontinued plasmapheresis and had no abdominal pain or PAs. In March 2017, the patient suffered from a PA due to diet violation. Within the first 12 months post treatment, overall quality of life improved, and no change in humoral or cellular immune response against LPL or AAV-1 was observed. In conclusion, alipogene tiparvovec was well tolerated, with a satisfactory response to treatment. Long-term effects on the recurrence of pancreatitis continue to be monitored.

A low resting metabolic rate in late childhood is associated with weight gain in adolescence

BACKGROUND AND OBJECTIVES

Lower total energy expenditure (TEE) and resting metabolic rate (RMR) are associated with greater weight gain in Native American adults. Whether these effects exist in childhood is unclear. We hypothesized that lower energy expenditure measured in childhood would predict greater relative change in body mass index (BMI) during adolescence.

METHODS

Measurements of height, weight, body composition, RMR and TEE were completed in 181 Native American children at exams done at age 5 and 10years, with 126 children having biennial follow-up assessments of weight and height after age 10years until age 20years. TEE and RMR were adjusted for age, sex, height, fat mass and fat free mass. BMI-change was assessed using population specific and Center for Disease Control (CDC) BMI z-scores and change in the relative difference to the 95th BMI-centile.

RESULTS

Lower adjusted RMR at age 10years was associated with greater increase in population-specific and CDC BMI z-scores, greater increase in the relative difference to the 95th BMI-centile and greater weight gain (all r≤-0.22, p≤0.01). However, no association was found with adjusted RMR at age 5years and with adjusted TEE and physical activity level assessed at age 5 or 10years.

CONCLUSIONS

Lower adjusted RMR at age 10years predicted greater change in adolescent BMI z-score indicating that the effects of relatively low metabolic rate on future weight gain in this population may begin in late childhood.

The interrelations between PCSK9 metabolism and cholesterol synthesis and absorption

Very few studies have investigated the interrelations between proprotein convertase subtilisin/kexin type 9 (PCSK9) metabolism, cholesterol synthesis, and cholesterol absorption. We aimed to address this issue in a large clinical trial of 245 patients with hypercholesterolemia. Serum lipids, PCSK9, lathosterol (cholesterol synthesis marker), campesterol, and sitosterol (cholesterol absorption markers) were measured before and 4-8 weeks after the start of treatment with PCSK9-antibodies (alirocumab or evolocumab). The patients had mean (standard error) LDL-cholesterol and PCSK9 concentrations of 3.87 (0.10) mmol/l and 356 (17) ng/ml, respectively. Eighty-four patients received no lipid-lowering pretreatment, 26 ezetimibe, 38 statins, and 97 ezetimibe + statins. Circulating PCSK9 increased in parallel with the potency of lipid-lowering pretreatment with circulating PCSK9 being highest in the ezetimibe + statin group (P < 0.001). Treatment with PCSK9-antibodies strongly decreased LDL-cholesterol, lathosterol, campesterol, and sitosterol (all P < 0.001) but hardly affected noncholesterol sterol to cholesterol ratios. Lipid-lowering pretreatment was not associated with the effects of PCSK9-antibodies on noncholesterol sterols (all P > 0.05). Summing up, circulating PCSK9 is increased by cholesterol synthesis and absorption inhibitors. Increased PCSK9 expression may partly explain the strong reductions of LDL-cholesterol achieved with PCSK9-antibodies after such pretreatment. On the other hand, treatment with PCSK9-antibodies does not significantly change the balance between cholesterol synthesis and absorption.