Gut-derived appetite hormones do not explain energy intake differences in humans following low-carbohydrate versus low-fat diets.

OBJECTIVE: The objective of this study was to explore how dietary macronutrient composition influences postprandial appetite hormone responses and subsequent energy intake. METHODS: A total of 20 adults (mean [SEM], age 30 [1] years, BMI 27.8 [1.3] kg/m2, n = 8 with normal weight, n = 6 with overweight, n = 6 with obesity) consumed a low-fat (LF) diet (10% fat, 75% carbohydrate) and a low-carbohydrate (LC) diet (10% carbohydrate, 75% fat) for 2 weeks each in an inpatient randomized crossover design. At the end of each diet, participants consumed isocaloric macronutrient-representative breakfast test meals, and 6-h postprandial responses were measured. Ad libitum energy intake was measured for the rest of the day. RESULTS: The LC meal resulted in greater mean postprandial plasma active glucagon-like peptide-1 (GLP-1; LC: 6.44 [0.78] pg/mL, LF: 2.46 [0.26] pg/mL; p < 0.0001), total glucose-dependent insulinotropic polypeptide (GIP; LC: 578 [60] pg/mL, LF: 319 [37] pg/mL; p = 0.0004), and peptide YY (PYY; LC: 65.6 [5.6] pg/mL, LF: 50.7 [3.8] pg/mL; p = 0.02), whereas total ghrelin (LC: 184 [25] pg/mL, LF: 261 [47] pg/mL; p = 0.0009), active ghrelin (LC: 91 [9] pg/mL, LF: 232 [28] pg/mL; p < 0.0001), and leptin (LC: 26.9 [6.5] ng/mL, LF: 35.2 [7.5] ng/mL; p = 0.01) were lower compared with LF. Participants ate more during LC at lunch (244 [85] kcal; p = 0.01) and dinner (193 [86] kcal; p = 0.04), increasing total subsequent energy intake for the day compared with LF (551 [103] kcal; p < 0.0001). CONCLUSIONS: In the short term, endogenous gut-derived appetite hormones do not necessarily determine ad libitum energy intake.

Physiology of the weight-loss plateau in response to diet restriction, GLP-1 receptor agonism, and bariatric surgery.

OBJECTIVE: The objective of this study was to investigate why different weight-loss interventions result in varying durations of weight loss prior to approaching plateaus. METHODS: A validated mathematical model of energy metabolism and body composition dynamics was used to simulate mean weight- and fat-loss trajectories in response to diet restriction, semaglutide 2.4 mg, tirzepatide 10 mg, and Roux-en-Y gastric bypass (RYGB) surgery interventions. Each intervention was simulated by adjusting two model parameters affecting energy intake to fit the mean weight-loss data. One parameter represented the persistent shift of the system from baseline equilibrium, and the other parameter represented the strength of the feedback control circuit relating weight loss to increased appetite. RESULTS: RYGB surgery resulted in a persistent intervention magnitude more than threefold greater than diet restriction and about double that of tirzepatide and semaglutide. All interventions except diet restriction substantially weakened the appetite feedback control circuit, resulting in an extended period of weight loss prior to the plateau. CONCLUSIONS: These preliminary mathematical modeling results suggest that both glucagon-like peptide 1 (GLP-1) receptor agonism and RYGB surgery interventions act to weaken the appetite feedback control circuit that regulates body weight and induce greater persistent effects to shift the body weight equilibrium compared with diet restriction.

Physiology of the Weight Loss Plateau after Calorie Restriction, GLP-1 Receptor Agonism, and Bariatric Surgery.

Objective: To investigate why different weight loss interventions result in varying durations of weight loss prior to approaching plateaus. Methods: A validated mathematical model of energy balance and body composition dynamics was used to simulate mean weight loss trajectories in response to intensive calorie restriction, semaglutide 2.4 mg, tirzepatide 10 mg, and Roux en-Y gastric bypass (RYGB) surgery interventions. Each intervention was simulated by varying two model parameters affecting energy intake to fit the observed mean weight loss data. One parameter represented the persistent magnitude of the intervention to shift the system from baseline equilibrium and the other parameter represented the strength of the feedback control circuit relating weight loss to increased appetite. Results: RYGB surgery resulted in a persistent intervention magnitude more than 4-fold greater than calorie restriction and about double that of tirzepatide and semaglutide. All interventions except calorie restriction substantially weakened the appetite feedback control circuit resulting in an extended period of weight loss prior to the plateau. Conclusions: These preliminary mathematical modeling results suggest that both GLP-1 receptor agonism and RYGB surgery interventions act to weaken the appetite feedback control circuit regulating body weight and induce greater persistent effects to shift the body weight equilibrium as compared to intensive calorie restriction.

Hypoxia and HIF-1α promote lytic de novo KSHV infection.

IMPORTANCE: The current view is that the default pathway of Kaposi's sarcoma-associated herpesvirus (KSHV) infection is the establishment of latency, which is a prerequisite for lifelong infection and viral oncogenesis. This view about KSHV infection is supported by the observations that KSHV latently infects most of the cell lines cultured in vitro in the absence of any environmental stresses that may occur in vivo. The goal of this study was to determine the effect of hypoxia, a natural stress stimulus, on primary KSHV infection. Our data indicate that hypoxia promotes euchromatin formation on the KSHV genome following infection and supports lytic de novo KSHV infection. We also discovered that hypoxia-inducible factor-1α is required and sufficient for allowing lytic KSHV infection. Based on our results, we propose that hypoxia promotes lytic de novo infection in cells that otherwise support latent infection under normoxia; that is, the environmental conditions can determine the outcome of KSHV primary infection.

Viral and immunologic evaluation of smokers with severe COVID-19.

Smoking negatively affects B cell function and immunoglobulin levels, but it is unclear if this immune dysfunction contributes to the risk of severe COVID-19 in smokers. We evaluated binding IgM, IgA and IgG antibodies to spike and receptor binding domain antigens, and used a pseudovirus assay to quantify neutralization titers in a set of 27 patients with severe COVID-19. We found no significant differences between binding and neutralization antibody responses for people with a smoking history and people who never smoked. High plasma viral load, but not antibody titers, was linked to an increased risk of death. Humoral immune dysfunction was not a major driver of severe COVID-19 in smokers.

New insights in the mechanisms of weight-loss maintenance: Summary from a Pennington symposium.

Obesity is a chronic disease that affects more than 650 million adults worldwide. Obesity not only is a significant health concern on its own, but predisposes to cardiometabolic comorbidities, including coronary heart disease, dyslipidemia, hypertension, type 2 diabetes, and some cancers. Lifestyle interventions effectively promote weight loss of 5% to 10%, and pharmacological and surgical interventions even more, with some novel approved drugs inducing up to an average of 25% weight loss. Yet, maintaining weight loss over the long-term remains extremely challenging, and subsequent weight gain is typical. The mechanisms underlying weight regain remain to be fully elucidated. The purpose of this Pennington Biomedical Scientific Symposium was to review and highlight the complex interplay between the physiological, behavioral, and environmental systems controlling energy intake and expenditure. Each of these contributions were further discussed in the context of weight-loss maintenance, and systems-level viewpoints were highlighted to interpret gaps in current approaches. The invited speakers built upon the science of obesity and weight loss to collectively propose future research directions that will aid in revealing the complicated mechanisms involved in the weight-reduced state.

Impact of Black Race on Peripheral Neuropathy in Patients With Newly Diagnosed Multiple Myeloma Receiving Bortezomib Induction.

PURPOSE: The incidence of multiple myeloma (MM) is two to three times higher in Black patients compared with other races, making it the most common hematologic malignancy in this patient population. Current treatment guidelines recommend the combination of a proteasome inhibitor, an immunomodulatory agent, and a corticosteroid as preferred induction therapy. Bortezomib use comes with the risk of peripheral neuropathy (PN) and potential need for dose reduction, therapy interruption, and additional supportive medications. Known risk factors for bortezomib-induced peripheral neuropathy (BIPN) include diabetes mellitus, previous thalidomide, advanced age, and obesity. We aimed to determine the potential association between Black race and incidence of BIPN. PATIENTS AND METHODS: We identified a cohort of 748 patients with newly diagnosed MM who received induction with bortezomib, lenalidomide, and dexamethasone from 2007 to 2016. One hundred forty Black patients were matched with 140 non-Black patients on age, sex, BMI, and route of bortezomib administration. Incidence of BIPN was a binary event defined as new use of a neuropathy medication, bortezomib dose reduction, dose omission, or discontinuation because of PN. RESULTS: The incidence of BIPN was higher in Black patients (46%) compared with non-Black patients (34%; P = .05) in both univariate (odds ratio [OR], 1.61; 95% CI, 1.00 to 2.61; P = .052) and multivariable analyses (OR, 1.64; 95% CI, 1.01 to 2.67; P = .047). No significant differences in BIPN were seen when stratified by route of administration. CONCLUSION: These data indicate that Black race is an independent risk factor for the development of BIPN. Additional prevention strategies, close monitoring, and appropriate supportive care measures are warranted for these patients.

The metabolic cost of physical activity in mice using a physiology-based model of energy expenditure.

OBJECTIVE: Physical activity is a major component of total energy expenditure (TEE) that exhibits extreme variability in mice. Our objective was to construct a general, physiology-based model of TEE to accurately quantify the energy cost of physical activity. METHODS: Spontaneous home cage physical activity, body temperature, TEE, and energy intake were measured with frequent sampling. The energy cost of activity was modeled considering six contributors to TEE (basal metabolic rate, thermic effect of food, body temperature, cold induced thermogenesis, physical activity, and body weight). An ambient temperature of 35 °C was required to remove the contribution from cold induced thermogenesis. Basal metabolic rate was adjusted for body temperature using a Q10 temperature coefficient. RESULTS: We developed a TEE model that robustly explains 70-80% of the variance in TEE at 35 °C while fitting only two parameters, the basal metabolic rate and the mass-specific energy cost per unit of physical activity, which averaged 60 cal/km/g body weight. In Ucp1-/- mice the activity cost was elevated by 60%, indicating inefficiency and increased muscle thermogenesis. The diurnal rhythm in TEE was quantitatively explained by the combined diurnal differences in physical activity, body temperature, and energy intake. Incorporating body temperature into human basal metabolic rate measurements significantly reduced the inter-individual variation. CONCLUSIONS: The physiology-based model of TEE allows quantifying the energy cost of physical activity. While applied here to mice, the model should be generally valid across species. Due to the effect of body temperature, we suggest that basal metabolic rate measurements be corrected to a reference body temperature, including in humans. Having an accurate cost of physical activity allows mechanistic dissection of disorders of energy homeostasis, including obesity.

CD8 T cells contribute to vaccine protection against SARS-CoV-2 in macaques.

Spike-specific neutralizing antibodies (NAbs) are generally considered key correlates of vaccine protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Recently, robust vaccine prevention of severe disease with SARS-CoV-2 variants that largely escape NAb responses has been reported, suggesting a role for other immune parameters for virologic control. However, direct data demonstrating a role of CD8+ T cells in vaccine protection have not yet been reported. In this study, we show that vaccine-elicited CD8+ T cells contribute substantially to virologic control after SARS-CoV-2 challenge in rhesus macaques. We vaccinated 30 macaques with a single immunization of the adenovirus vector-based vaccine Ad26.COV2.S or sham and then challenged them with 5 × 105 median tissue culture infectious dose SARS-CoV-2 B.1.617.2 (Delta) by the intranasal and intratracheal routes. All vaccinated animals were infected by this high-dose challenge but showed rapid virologic control in nasal swabs and bronchoalveolar lavage by day 4 after challenge. However, administration of an anti-CD8α- or anti-CD8ß-depleting monoclonal antibody in vaccinated animals before SARS-CoV-2 challenge resulted in higher levels of peak and day 4 virus in both the upper and lower respiratory tracts. These data demonstrate that CD8+ T cells contribute substantially to vaccine protection against SARS-CoV-2 replication in macaques.

Impact of concurrent gabapentin or pregabalin with high-dose melphalan in patients with multiple myeloma undergoing autologous hematopoietic stem cell transplant.

BACKGROUND: Melphalan is an alkylating agent used in both autologous (ASCT) and allogeneic stem cell transplantation. It is a substrate of L-type amino acid transporter-1 (LAT-1) and LAT-2, which are involved in its tissue penetration and elimination. Gabapentin and pregabalin, common concomitant medications in patients with multiple myeloma undergoing ASCT, are also substrates of LAT transporters, raising concern for potential competitive inhibition of melphalan transport. We evaluated whether concurrent use of gabapentin or pregabalin in patients receiving high-dose melphalan (≥140 mg/m2 ) prior to ASCT impacted frequency and severity of melphalan-related adverse events. OBJECTIVE: We aimed to determine if concurrent administration of gabapentin or pregabalin and melphalan increased melphalan toxicity. METHODS: This was a single-center, retrospective evaluation including patients ≥18 years of age who received high-dose melphalan as part of a conditioning regimen at the Winship Cancer Institute of Emory University between August 1, 2010 and April 1, 2020 and were followed through their transplant admission. After identification and inclusion of patients who received melphalan in combination with gabapentin or pregabalin, patient matching based on age (±5 years), sex, and melphalan dose (140 mg/m2 or 200 mg/m2 ) was utilized to generate a comparable cohort of patients who received melphalan alone. The primary outcome was hospital length of stay (LOS); secondary outcomes included supportive care requirements between days +4 and day +14 and time to neutrophil and platelet-20 engraftment. RESULTS: Among 176 patients evaluated in each group, median hospital LOS was 16 days, median time to neutrophil engraftment was 14 days, and median time to platelet-20 engraftment was 16 days in both groups. In addition, there were no significant differences in supportive care requirements between groups. CONCLUSION: In this study, use of gabapentin or pregabalin in combination with melphalan did not impact safety of the conditioning regimen in patients undergoing ASCT.

Safety and Efficacy of 7 Days on/7 Days off Versus 14 Days on/7 Days off Schedules of Capecitabine in Patients with Metastatic Colorectal Cancer: A Retrospective Review.

INTRODUCTION/BACKGROUND: The administration schedule of capecitabine for the treatment of metastatic colorectal cancer (mCRC) in clinical trials has been 14 days of drug with 7 days off in a 21 day cycle (14/7). In an effort to improve tolerability, an alternative every other week treatment (7/7) is often administered. The purpose of this study was to determine the safety and efficacy of administering 7/7 compared with 14/7 capecitabine dosing. MATERIALS AND METHODS: In this retrospective study, mCRC patients received capecitabine on a 7/7 or 14/7 schedule. The primary objective was to determine the tolerability of the respective dosing schedules, defined according to frequency of dose reductions and treatment delays. Secondary objectives included comparisons of objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety of dosing strategies. RESULTS: Of 175 included patients, 73 (41.7%) received the capecitabine 7/7 schedule and 102 (58.3%) received the 14/7 schedule. There was a statistically significant difference between the 7/7 and 14/7 groups with regard to dose reductions (4% vs. 29%; P < .001) and treatment delays (22% vs. 43%; P = .004). The incidence of any adverse effects (45% vs. 72%; P < .001) and specifically, palmar-plantar erythrodysesthesia (18% vs. 45%; P < .001), were significantly higher in the 14/7 group. No significant difference was seen with regard to ORR, PFS, or OS. CONCLUSION: Patients with mCRC who received the 7/7 schedule had significantly fewer dose reductions and treatment delays compared with patients who received the 14/7 schedule. Although no difference in efficacy outcomes were observed, prospective studies are needed to confirm these findings.

Describing the Weight-Reduced State: Physiology, Behavior, and Interventions.

Although many persons with obesity can lose weight by lifestyle (diet and physical activity) therapy, successful long-term weight loss is difficult to achieve, and most people who lose weight regain their lost weight over time. The neurohormonal, physiological, and behavioral factors that promote weight recidivism are unclear and complex. The National Institute of Diabetes and Digestive and Kidney Diseases convened a workshop in June 2019, titled "The Physiology of the Weight-Reduced State," to explore the mechanisms and integrative physiology of adaptations in appetite, energy expenditure, and thermogenesis that occur in the weight-reduced state and that may oppose weight-loss maintenance. The proceedings from the first session of this workshop are presented here. Drs. Michael Rosenbaum, Kevin Hall, and Rudolph Leibel discussed the physiological factors that contribute to weight regain; Dr. Michael Lowe discussed the biobehavioral issues involved in weight-loss maintenance; Dr. John Jakicic discussed the influence of physical activity on long-term weight-loss maintenance; and Dr. Louis Aronne discussed the ability of drug therapy to maintain weight loss.

The Effect of Adjuvant Pelvic Radiotherapy on Distant Metastasis for Uterine Carcinosarcoma.

BACKGROUND: Uterine carcinosarcomas (UCS) are rare tumors that carry a poor prognosis and high recurrence rate. Standard treatment consists of surgical resection and chemotherapy, though the benefit of adjuvant radiotherapy (RT) has yet to be determined. This study assessed survival rates between patients with UCS who underwent surgical resection alone and patients who underwent combinations of surgery, chemotherapy, and RT. MATERIALS AND METHODS: We conducted a retrospective review of all patients who underwent surgical resection for UCS between 1993 and 2011 at a single institution. We assessed 3-year disease-free survival, locoregional recurrence-free survival, distant metastases-free survival (DMFS), and overall survival rates and utilized Kaplan-Meier modeling to analyze differences between UCS treatment modalities. RESULTS: Twenty-four patients underwent UCS surgical resection between 1993 and 2011. The mean age was 61 (range: 39 to 75 y). Of these patients, 100% (n=24) underwent surgical resection, 25% (n=6) underwent surgery and adjuvant chemotherapy, 29% (n=7) underwent surgery and adjuvant RT, and 33% (n=8) underwent surgery and adjuvant chemotherapy and RT. At 3 years median follow, there was no significant difference in overall survival between treatment modalities. The addition of radiation therapy conferred increased DMFS in patients undergoing surgery irrespective of adjuvant chemotherapy (44% vs. 83%, P=0.0211).In patients receiving adjuvant chemotherapy, the significant increase in DMFS persisted with the addition of RT (P=0.0310). Lymph node involvement (n=8) was associated with a lower locoregional recurrence-free survival (38% vs. 92%, P=0.0029). CONCLUSIONS: RT may offer a potential benefit in reducing the rate of distant metastases, though there were no statistically significant improvements in survival metrics.

Pulmonary arterial venous malformations as primary manifestation of gestational trophoblastic neoplasia.

•A unique initial presentation of GTN as pulmonary arteriovenous malformations.•Metastatic GTN presenting as multiple visceral AVMs in the brain, liver, and lungs.•Management of metastatic GTN with brain metastases with induction chemotherapy.

New and Worsening Long-term Immune-Related Adverse Events with PD-1/PD-L1 Pathway Agents in Patients with Cancer.

STUDY OBJECTIVES: Immune checkpoint inhibitors have produced durable responses across a variety of cancers. Although programmed cell death protein 1 (PD-1) and its ligand (PD-L1) inhibitors activate T cells against tumor cells, they may also cause autoimmune-like toxicities termed immune-related adverse events (irAEs). Although much is known regarding irAEs that occur early during treatment, data on the long-term toxicity profile of these agents are more limited. Our primary objective was to evaluate the frequency of patients receiving anti-PD-1/PD-L1 therapy for at least 6 continuous months who experienced new or worsening irAEs requiring clinical interventions. Secondary objectives included assessment of other factors associated with clinically significant irAEs after at least 6 months of therapy. DESIGN: Retrospective chart review. SETTING: Large university-affiliated National Cancer Institute-designated comprehensive cancer center. PATIENTS: A total of 159 adults diagnosed with any malignancy who received a PD-1/PD-L1 inhibitor-nivolumab, pembrolizumab, or atezolizumab-as monotherapy or with concurrent cytotoxic agents, for at least 6 months, between January 1, 2014, and September 1, 2017. MEASUREMENTS AND MAIN RESULTS: We collected information on the incidence and timing of irAEs, along with patient demographics and other treatment outcomes. Thirty-eight patients (24%) experienced clinically significant, new, or worsening irAEs after 6 months of treatment with anti-PD-1/PD-L1 therapy. Hypothyroidism was the most common irAE experienced (20 patients [12.6%]), followed by pneumonitis (5 patients [3%]); 2 patients died due to pneumonitis. Four patients (2.5%) had a deepened disease response beyond 6 months of treatment. CONCLUSION: Our results revealed that a significant proportion of patients continue to experience irAEs with long-term use of PD-1/PD-L1 inhibitors. These results further contribute to the risk-benefit understanding of chronic PD-1/PD-L1 antagonism and support discontinuation of these agents following deepest response.

Intrathecal Central Nervous System Prophylaxis in Patients With Diffuse Large B-cell Lymphoma at an Academic Healthcare System.

INTRODUCTION: Intrathecal chemoprophylaxis is often administered to patients with diffuse large B-cell lymphoma (DLBCL) to lower the rates of central nervous system (CNS) relapse, although its benefit has not been well-described. Prognostic models, including the CNS-International Prognostic Index (IPI), have been developed to aid in identifying patients at highest risk for CNS relapse. PATIENTS AND METHODS: We evaluated 112 patients diagnosed with DLBCL from 2009 to 2016 at Emory Healthcare and classified them as high (n = 44) or low risk (n = 68) for CNS relapse and compared CNS prophylaxis rates and relapse rates between groups. The primary outcome was to compare the CNS relapse rate in high-risk patients who received intrathecal prophylaxis with patients who did not. RESULTS: Twenty-six patients (14 high-risk and 12 low-risk) received intrathecal prophylaxis. Only 4 of 112 patients experienced a CNS relapse, including 1 in the high-risk group and 3 in the low-risk group. Among 14 high-risk patients who received intrathecal prophylaxis, no patient experienced CNS relapse compared with 1 of 30 high-risk patients without prophylaxis (P = 1.0). CONCLUSION: Given the low rates of CNS relapse in this series, it is difficult to discern the impact of current risk stratification combined with intrathecal prophylaxis on outcomes. Our observation that many high-risk patients did not receive prophylaxis, whereas many low-risk patients received prophylaxis emphasizes the need for a standardized approach.

How to Decide Which DLBCL Patients Should Receive CNS Prophylaxis.

Secondary central nervous system (CNS) relapse in aggressive non-Hodgkin lymphoma (NHL) is a dismal diagnosis with poor outcomes. While prophylaxis against secondary CNS disease is recommended in patients with highly aggressive NHLs, such as Burkitt lymphoma, patients with diffuse large B-cell lymphoma (DLBCL) present a challenging clinical dilemma due to an inherently lower risk of CNS relapse. Current guidelines suggest that prophylaxis may benefit DLBCL patients at high risk for CNS relapse; however, it has been difficult to define which patients are truly at high risk. Many studies have attempted to clarify the issue, with conflicting results. Here we review current prognostic models, risk factors, and prophylaxis methods to provide a practical approach to preventing CNS relapse in patients with DLBCL.