His work has resulted in patents for diagnostic and therapeutic applications and has contributed to pharmaceutical companies' development of new pharmaceuticals. Currently, he and his team are utilizing various interventions, including physiological, pharmacological, and dietary interventions, and tools related to physiology, hormones, neurocognition, neuroimaging, and functional MRI to investigate the role of the human brain and peripheral organs in regulating energy homeostasis, obesity, and metabolism and associated comorbidities like diabetes, NASH, cardiovascular diseases, and malignancies.
In 2018, Mantzoros gave a Harvard Medical School Mini Med lecture to teach medical concepts to a lay audience attended by nearly 100,000 people worldwide through live-streaming.[4][5]
Leptin and Adiponectin
Mantzoros conducted physiology and pharmacokinetic studies in leptin, ran clinical trials in humans, and investigated its therapeutic potential. He was among the first to investigate the normal physiology of leptin in humans, including circadian rhythms its role in fasting, neuroendocrine regulation in humans, and concerning body weight.[6][7][8][9][10][11][12][excessive citations] His team has studied leptin pharmacokinetics, establishing dosing guidelines for human use.[10][11][13] Their work advanced understanding of leptin's neuroendocrine roles in body weight regulation, energy homeostasis, immunology, and interactions with hormones like thyroid-stimulating hormone and sex steroids.[14]
Noting that hypothalamicamenorrhea (HA), extreme leanness, and lipodystrophy involve hypoleptinemia, he led clinical trials testing leptin therapy.[15][16] Results showed leptin replacement restored hormonal axes and bone density in HA, while improving insulin resistance and metabolic dysfunction in lipodystrophy.[14][13][17][16][18][excessive citations] Additionally, he observed that functional changes in how the brain views food occur in subjects with hypoleptinemia, which can be corrected with leptin replacement.[19] Mantzoros and his team observed that short-term metreleptin treatment enhanced activity in areas detecting food's salience and rewarding value during fasting. In contrast, long-term treatment decreased attention to the rewarding value of food after feeding. Furthermore, hypothalamic activity is modulated by metreleptin treatment, and leptin reduces functional connectivity of the hypothalamus to key feeding-related areas in these hypoleptinemic subjects.
These findings expanded the role of leptin from that of a hormone regulating energy expenditure to one important in systemic neuroendocrine regulation. Mantzoros's team subsequently focused on physiology studies to explore and elucidate determinants of adiponectin levels in the circulation and the physiological role of adiponectin in humans.[20]
Proglucagon derived peptides
More recently, Mantzoros's interest has been directed towards the physiology and clinical significance of GIP and the proglucagon-derived peptides, including endogenous GLP-1, glucagon-like peptide-2, glucagon, oxyntomodulin, glicentin, and major proglucagon fragment, which play a significant role in metabolic homeostasis and weight regulation.[21] Among other physiology and interventional studies, Mantzoros published a randomized control trial that showed that the administration of the GLP-1 analog liraglutide to overweight/obese individuals leads to downregulation of other proglucagon-derived molecules; this suggests that normalizing the decreasing levels of several of these molecules may provide additional metabolic and weight loss benefits in the future.[22]
Neuroimaging studies
Mantzoros has been working on the interplay of hormones and environmental factors to influence the function of essential brain centers in energy homeostasis and metabolism and how these may be altered with pharmaceuticals to treat obesity, with a focus on the control of eating behaviors as they are affected by obesity in the human cortex.[23]
Mantzoros and his team examined the GLP-1 analog liraglutide in diabetic adults and found that liraglutide decreased activation in the brain's cortex, increasing control and making individuals more attentive to their eating.[24] This suggests that individuals on liraglutide find highly desirable foods less appealing and that the medication might prove an effective weight loss therapy for people who eat foods as a reward, such as when stressed.
Short-term treatment with GLP-1RAs decreases activation in the insula, putamen, caudate, and orbitofrontal cortex (areas of the reward system), which may lead to lower energy intake and may thus contribute to weight loss; however, the impact of GLP-1RAs on brain activity disappears during long-term treatment, which may also explain the eventual weight-loss plateau observed with these medications.[25]
Furthermore, Mantzoros and colleagues examined the serotonin 2c receptor agonist lorcaserin in obese adults and discovered that lorcaserin decreased activation in the attention-related parietal and visual cortices in response to highly palatable food cues at 1 week in the fasting state and in the parietal cortex in response to any food cues at 4 weeks in the fed state.[26] The decrease in emotion—and salience-related limbic activity, including the insula and amygdala, was attenuated at 4 weeks. In a secondary analysis, they observed that decreases in caloric intake, weight, and BMI correlated with activations in the amygdala, parietal, and visual cortices at baseline, suggesting that lorcaserin would benefit emotional eaters.
Mantzoros' team performed the first neuroimaging study investigating the association of blood concentrations of oxyntomodulin, glicentin, and GIP with brain activity in response to food cues.[27] Findings showed that fasting blood levels of GIP were inversely associated with the activation of attention-related areas (visual cortices of the occipital lobe and parietal lobe), oxyntomodulin and glicentin with reward-related areas (insula, putamen, caudate for both, and additionally orbitofrontal cortex for glicentin), and the hypothalamus when viewing highly desirable as compared to less desirable food images.[citation needed]
Non-alcoholic fatty liver disease and steatohepatitis
In addition to his work on obesity and diabetes, recognizing the rising burden of NAFLD, which currently affects approximately 30% of Americans, Mantzoros has focused on the pathophysiology of the disease and the development of diagnostic, prognostic, and therapeutic tools.
Regarding pathophysiology, the Mantzoros group has linked NAFLD to central obesity and the hormones leptin and adiponectin as well as low skeletal mass and skeletal tissue hormones, including activins, follistatins, irisin, the quality of the diet and the protective role of the Mediterranean diet.[28][29][30][31][32][33][34][35][36][excessive citations]
The Mantzoros team, using the techniques of omics and supervised learning, has developed novel models utilizing a top-down approach instead of the usual candidate molecule approach, like using metabolites, lipids, hormones, and glycans that can diagnose the presence of NASH, NAFLD or healthy status with high accuracy, as well as a model that can diagnose liver fibrosis using lipids.[37][38] He has further focused on the emerging role of antidiabetic and other medications necessary in metabolism suggested to be used on the background of medical nutrition and lifestyle modification therapy for the treatment of advanced NASH.[39][40][41][42][43]
For these reasons, Mantzoros has proposed a new name and classification for this disease: DAFLD/DASH (Dysmetabolism Associated Fatty Liver Disease / Steatohepatitis), placing it as an umbrella diagnosis under a pathophysiology-based subclassification of fatty liver disease (FLD).[44]
Mantzoros, representing the Endocrine Society, has participated in the working group that published the "call to action" paper inviting primary care physicians and subspecialists to prepare for the epidemic of this prevalent condition and to contribute to screening, diagnosing, and treating it in their clinics.[45] This working group subsequently published the 2021 guidelines on diagnosis and treatment.
Epidemiology of cancer
Observing that the incidence of certain cancers, such as endometrial, esophageal, and breast cancers, increases with the rate of obesity, Mantzoros hypothesized that insulin-like growth factor 1 (IGF-1), which is also found at higher levels in obesity and is a growth factor, might be related to the development of cancer. He first confirmed in a case-control study that IGF-1 was linked with prostate cancer.[46][47][48] Later, in case-control and prospective epidemiology studies, he confirmed a similar link between IGF-1 and other cancers, including thyroid and breast.[49][50][51] This work opened the way for efforts to develop molecules blocking IGF-1 signaling as possible treatments for cancer, which are currently being tested.
Additionally, observing the links between insulin resistance, inflammation, and sex steroids with central obesity and obesity-related cancers, Mantzoros expanded this research to the molecule adiponectin, hypothesizing that abnormalities in this molecule, caused by abnormal fat deposition in the abdomen, were upstream of all other hormonal and inflammatory abnormalities above. First performing physiology studies in rodents and later in human case-control and prospective cohort studies, his team demonstrated the link between adiponectin and several types of cancer, including breast, colorectal, thyroid, prostate, and others.[49][50][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][excessive citations]
The Mantzoros group also demonstrated a direct effect of adiponectin and its receptors on human endometrial and other cancers, and began mapping the molecular pathways downstream of adiponectin in malignancies.[58][59]
Mediterranean Diet
Mantzoros demonstrated that following a Mediterranean diet leads to improved levels of adipokines like adiponectin, which decreases insulin resistance and inflammatory factors like C-reactive protein and thus leads in the long-term to a lower incidence of death from cardiovascular disease and stroke.[78][79][80][81][82][83][84]
Metabolism: Clinical and Experimental
Metabolism: Clinical and Experimental is a biomedical journal published by Elsevier that covers all aspects of metabolism, including studies in human, animal, and cellular models. The journal was in decline for several years until 2010, when Mantzoros assumed the position of editor-in-chief.
Since then, the journal has experienced a growth of more than 20% annually in all metrics, and its impact factor has more than quadrupled (current IF: 13.93). The impact factor and cite score (4-year impact factor) has placed Metabolism: Clinical and Experimental in the top 3% of endocrinology, diabetes, and metabolism journals. Its cited half-life, or the duration an average paper continues receiving citations, was 9.4 in 2018, placing the journal in the top 5% of its category.[85] The 2022 journal cite score was 16.5.[citation needed]
Translation of science into tangible clinical benefits
Mantzoros heads Mantzoros Consulting, LLC, which consults for several companies. In 2005, he co-founded Intekrin, Inc., which was later acquired by and merged with Coherus, Inc.[86] These companies are developing several biosimilars at various stages of clinical development in humans (one is approaching FDA approval) and small molecules for diseases related to insulin resistance (e.g, diabetes and NAFLD). CHRS-131 completed Phase II trials in humans for multiple sclerosis.[87]
Teaching and mentoring
Mantzoros is the chief of endocrinology, diabetes, and metabolism at the VA Boston Healthcare System and the director of the Human Nutrition Unit at Beth Israel Deaconess Medical Center. He teaches at Harvard Medical School and Boston University School of Medicine. He has mentored more than 175 scientists.[citation needed]
Mantzoros, an active member of the Eastern Orthodox Catholic Church, has held many roles, including teaching pro bono biomedical ethics at the Hellenic College and Holy Cross School of Theology, serving on the Archdiocesan Advisory Council on Bioethics, and serving on the Hellenic College Holy Cross (HCHC) board of trustees.[citation needed]
1 2 Roemmich, James N; Clark, Pamela A; Berr, Stuart S; Mai, Vu; Mantzoros, Christos S; Flier, Jeffrey S; Weltman, Arthur; Rogol, Alan D (1998). "Gender differences in leptin levels during puberty are related to the subcutaneous fat depot and sex steroids". American Journal of Physiology. Endocrinology and Metabolism. 275 (3): E543-51. doi:10.1152/ajpendo.1998.275.3.E543. PMID9725824.
1 2 Chan, Jean L; Mantzoros, Christos S (2005). "Role of leptin in energy-deprivation states: Normal human physiology and clinical implications for hypothalamic amenorrhoea and anorexia nervosa". The Lancet. 366 (9479): 74–85. doi:10.1016/S0140-6736(05)66830-4. PMID15993236. S2CID37180870.
↑ Perakakis, Nikolaos; Kokkinos, Alexander; Peradze, Natia; Tentouris, Nikolaos; Ghaly, Wael T; Pilitsi, Elena; Upadhyay, Jagriti; Alexandrou, Andreas; Mantzoros, Christos S (2019). "Circulating levels of gastrointestinal hormones in response to the most common types of bariatric surgery and predictive value for weight loss over one year: Evidence from two independent trials". Metabolism. 101 153997. doi:10.1016/j.metabol.2019.153997. PMID31672446. S2CID209568403.
↑ Polyzos, Stergios A; Perakakis, Nikolaos; Mantzoros, Christos S (2019). "Fatty liver in lipodystrophy: A review with a focus on therapeutic perspectives of adiponectin and/or leptin replacement". Metabolism. 96: 66–82. doi:10.1016/j.metabol.2019.05.001. PMID31071311. S2CID195661123.
↑ Polyzos, Stergios A; Kountouras, Jannis; Anastasilakis, Athanasios D; Geladari, Eleni V; Mantzoros, Christos S (2014). "Irisin in patients with nonalcoholic fatty liver disease". Metabolism. 63 (2): 207–17. doi:10.1016/j.metabol.2013.09.013. PMID24140091.
↑ Kouvari, Matina; Boutari, Chrysa; Chrysohoou, Christina D; Fragkopoulou, Elizabeth; Antonopoulou, Smaragdi; Tousoulis, Dimitrios; Pitsavos, Christos; Panagiotakos, Demosthenes B; Mantzoros, Christos S (2021). "Mediterranean diet is inversely associated with steatosis and fibrosis and decreases ten-year diabetes and cardiovascular risk in NAFLD subjects: Results from the ATTICA prospective cohort study". Clinical Nutrition (Edinburgh, Scotland). 40 (5): 3314–3324. doi:10.1016/j.clnu.2020.10.058. PMID33234342. S2CID227169217.
↑ Lee, Saehyun; Ko, Byung-Joon; Gong, Younghoon; Han, Kyungdo; Lee, Anna; Han, Byoung-Duck; Yoon, Yeo Joon; Park, Siyoung; Kim, Jung-Hyun; Mantzoros, Christos S (2016). "Self-reported eating speed in relation to non-alcoholic fatty liver disease in adults". European Journal of Nutrition. 55 (1): 327–33. doi:10.1007/s00394-015-0851-z. PMID25648740. S2CID36907141.
↑ Perakakis, Nikolaos; Polyzos, Stergios A; Yazdani, Alireza; Sala-Vila, Aleix; Kountouras, Jannis; Anastasilakis, Athanasios D; Mantzoros, Christos S (2019). "Non-invasive diagnosis of non-alcoholic steatohepatitis and fibrosis with the use of omics and supervised learning: A proof of concept study". Metabolism. 101 154005: 1540054. doi:10.1016/j.metabol.2019.154005. PMID31711876. S2CID207962497.
↑ Polyzos, Stergios A; Kountouras, Jannis; Mantzoros, Christos S; Polymerou, Vaia; Katsinelos, Panagiotis (2017). "Effects of combined low-dose spironolactone plus vitamin E vs vitamin E monotherapy on insulin resistance, non-invasive indices of steatosis and fibrosis, and adipokine levels in non-alcoholic fatty liver disease: a randomized controlled trial". Diabetes, Obesity & Metabolism. 19 (12): 1805–1809. doi:10.1111/dom.12989. PMID28452101. S2CID19982214.
↑ Perakakis, Nikolaos; Stefanakis, Konstantinos; Feigh, Michael; Veidal, Sanne S; Mantzoros, Christos S (2021). "Elafibranor and liraglutide improve differentially liver health and metabolism in a mouse model of non-alcoholic steatohepatitis". Liver International. 41 (8): 1853–1866. doi:10.1111/liv.14888. ISSN1478-3223. PMID3788377. S2CID232430841.
↑ Athyros, Vasilios G; Alexandrides, Theodore K; Bilianou, Helen; Cholongitas, Evangelos; Doumas, Michael; Ganotakis, Emmanuel S; Goudevenos, John; Elisaf, Moses S; Germanidis, Georgios; Giouleme, Olga; Karagiannis, Asterios; Karvounis, Charalambos; Katsiki, Niki; Kotsis, Vasilios; Kountouras, Jannis; Liberopoulos, Evangelos; Pitsavos, Christos; Polyzos, Stergios; Rallidis, Loukianos S; Richter, Dimitrios; Tsapas, Apostolos G; Tselepis, Alexandros D; Tsioufis, Konstantinos; Tziomalos, Konstantinos; Tzotzas, Themistoklis; Vasiliadis, Themistoklis G; Vlachopoulos, Charalambos; Mikhailidis, Dimitri P; Mantzoros, Christos (2017). "The use of statins alone, or in combination with pioglitazone and other drugs, for the treatment of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis and related cardiovascular risk. An Expert Panel Statement". Metabolism. 71: 17–32. doi:10.1016/j.metabol.2017.02.014. PMID28521870.
↑ Valenzuela-Vallejo, Laura; Mantzoros, Christos S. (2022). "Time to transition from a negative nomenclature describing what NAFLD is not, to a novel, pathophysiology-based, umbrella classification of fatty liver disease (FLD)". Metabolism. 134 155246. doi:10.1016/j.metabol.2022.155246. PMID35780909. S2CID250232304.
↑ Wolk, A; Andersson, S. O; Mantzoros, C. S; Trichopoulos, D; Adami, H. O (2000). "Can measurements of IGF-1 and IGFBP-3 improve the sensitivity of prostate-cancer screening?". The Lancet. 356 (9245): 1902–3. doi:10.1016/S0140-6736(00)03266-9. PMID11130391. S2CID28845541.
1 2 Moschos, S. J; Mantzoros, C. S (2002). "The role of the IGF system in cancer: From basic to clinical studies and clinical applications". Oncology. 63 (4): 317–32. doi:10.1159/000066230. PMID12417786. S2CID1441480.
1 2 Pazaitou-Panayiotou, Kalliopi; Panagiotou, Grigorios; Polyzos, Stergios A; Mantzoros, Christos S (2016). "Serum Adiponectin and Insulin-Like Growth Factor 1 in Predominantly Female Patients with Thyroid Cancer: Association with the Histologic Characteristics of the Tumor". Endocrine Practice. 22 (1): 68–75. doi:10.4158/EP15814.OR. PMID26484409.
↑ Barb, D; Pazaitou-Panayiotou, K; Mantzoros, C. S (2006). "Adiponectin: A link between obesity and cancer". Expert Opinion on Investigational Drugs. 15 (8): 917–31. doi:10.1517/13543784.15.8.917. PMID16859394. S2CID23979628.
↑ Michalakis, Konstantinos; Venihaki, Maria; Mantzoros, Christos; Vazaiou, Andriani; Ilias, Ioannis; Gryparis, Alexandros; Margioris, Andrew N (2015). "In prostate cancer, low adiponectin levels are not associated with insulin resistance". European Journal of Clinical Investigation. 45 (6): 572–8. doi:10.1111/eci.12445. PMID25833038. S2CID205093762.
↑ Dalamaga, Maria; Karmaniolas, Konstantinos; Panagiotou, Anna; Hsi, Alex; Chamberland, John; Dimas, Cleanthi; Lekka, Antigoni; Mantzoros, Christos S (2008). "Low circulating adiponectin and resistin, but not leptin, levels are associated with multiple myeloma risk: A case–control study". Cancer Causes & Control. 20 (2): 193–9. doi:10.1007/s10552-008-9233-7. PMID18814045. S2CID11372840.
↑ Sher, David J; Oh, William K; Jacobus, Susanna; Regan, Meredith M; Lee, Gwo-Shu; Mantzoros, Christos (2008). "Relationship between serum adiponectin and prostate cancer grade". The Prostate. 68 (14): 1592–8. doi:10.1002/pros.20823. PMID18646046. S2CID41752707.
↑ Mantzoros, C. S; Trakatelli, M; Gogas, H; Dessypris, N; Stratigos, A; Chrousos, G. P; Petridou, E. T (2007). "Circulating adiponectin levels in relation to melanoma: A case-control study". European Journal of Cancer. 43 (9): 1430–6. doi:10.1016/j.ejca.2007.03.026. PMID17512191.
↑ Dal Maso, L; Augustin, L. S; Karalis, A; Talamini, R; Franceschi, S; Trichopoulos, D; Mantzoros, C. S; La Vecchia, C (2004). "Circulating adiponectin and endometrial cancer risk". The Journal of Clinical Endocrinology & Metabolism. 89 (3): 1160–3. doi:10.1210/jc.2003-031716. PMID15001602. S2CID30271923.
↑ Mantzoros, C; Petridou, E; Dessypris, N; Chavelas, C; Dalamaga, M; Alexe, D. M; Papadiamantis, Y; Markopoulos, C; Spanos, E; Chrousos, G; Trichopoulos, D (2004). "Adiponectin and breast cancer risk". The Journal of Clinical Endocrinology & Metabolism. 89 (3): 1102–7. doi:10.1210/jc.2003-031804. PMID15001594.
↑ Ko, Byung-Joon; Park, Kyung Hee; Mantzoros, Christos S (2014). "Diet patterns, adipokines, and metabolism: Where are we and what is next?". Metabolism. 63 (2): 168–77. doi:10.1016/j.metabol.2013.11.004. PMID24360751.
↑ Yannakoulia, Mary; Yiannakouris, Nikos; Melistas, Labros; Kontogianni, Meropi D; Malagaris, Ioannis; Mantzoros, Christos S (2008). "A dietary pattern characterized by high consumption of whole-grain cereals and low-fat dairy products and low consumption of refined cereals is positively associated with plasma adiponectin levels in healthy women". Metabolism. 57 (6): 824–30. doi:10.1016/j.metabol.2008.01.027. PMID18502266.
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