Jonathan Frederik Brozat

Dr. Jonathan Frederik Brozat

orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 October 2021 in Surgical Endoscopy
Verified
Journal Article
Open access
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Sophia M. SchmitzSophia M. Schmitz
Sophia M. Schmitz
PAPatrick H. Alizai
Patrick H. Alizai
AKAndreas Kroh
Andreas Kroh
SSSandra Schipper
Sandra Schipper
JBJonathan Frederik Brozat
Jonathan Frederik Brozat
TUTom F. Ulmer
Tom F. Ulmer
Background: Bariatric surgery in super-super-obese (SSO) patients remains a continuous challenge due to intraabdominal fat masses, higher liver volume and existing comorbidities. A convenient procedure in SSO patients is one anastomosis gastric bypass (OAGB). The aim of this study was to compare the outcome of SSO patients undergoing OAGB in comparison to laparoscopic sleeve gastrectomy (LSG). Methods: We retrospectively reviewed data from SSO patients who underwent OAGB and LSG in our institution between 2008 and 2020. Primary endpoints included percentage total body weight loss and percentage BMI loss at 12, 24, and 36 months after the operation. Secondary endpoints were perioperative complications, procedure length, length of hospital stay and outcome of comorbidities. Results: 243 patients were included in this study. 93 patients underwent LSG and 150 underwent OAGB. At any of the time points evaluated, weight loss in patients after OAGB was greater than in LSG patients, while procedure length was significantly shorter for OAGB than LSG (81.4 vs. 92.1 min, p-value < 0.001). Additionally, mean length of hospital stay was shorter in the OAGB group (3.4 vs. 4.5 days, p-value < 0.001). There were more severe complications (Clavien-Dindo ≥ 3a) in the LSG group (11.8% vs 2.7%, p-value = 0.005). Conclusion: In this retrospective analysis, OAGB was superior to LSG in terms of weight loss in SSO patients. Procedure length and hospital stay were shorter after OAGB in comparison to LSG and there were fewer severe complications. OAGB can therefore be regarded a safe and effective treatment modality for SSO patients.

23 November 2020 in Diagnostics
Verified
Journal Article
Open access
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TWTheresa Wirtz
Theresa Wirtz
LBLukas Buendgens
Lukas Buendgens
Ralf WeiskirchenRalf Weiskirchen
Ralf Weiskirchen
SLSven Loosen
Sven Loosen
NHNina Haehnsen
Nina Haehnsen
AKAlexander Koch
Alexander Koch
Background: Calprotectin is present in the cytosol of neutrophil granulocytes and released upon activation. Fecal calprotectin is applied in the clinical management of inflammatory bowel disease whereas serum calprotectin has been discussed as a biomarker in inflammatory disorders. However, its long-term prognostic relevance in critical illness remains unclear. Our aim was to investigate serum calprotectin concentrations as a prognostic biomarker in critically ill and septic patients. Methods: Serum calprotectin concentrations were analyzed in 165 critically ill patients (108 with sepsis, 57 without sepsis) included in our observational study. Patients were enrolled upon admission to the medical intensive care unit (ICU) of the RWTH Aachen University Hospital. Calprotectin concentrations were compared to 24 healthy controls and correlated with clinical parameters, therapeutic interventions, and survival. Results: Serum calprotectin concentrations were significantly increased in ICU patients as well as in septic patients compared to respective controls (p < 0.001 for ICU patients and p = 0.001 for septic patients). Lower calprotectin concentrations were measured in patients with comorbidities i.e., coronary artery disease. Calprotectin concentrations strongly correlated with the C-reactive protein (p < 0.001) and were closely associated to parameters of mechanical ventilation (i.a. inspiratory oxygen fraction, FiO2; p < 0.001). The overall survival was significantly impaired in septic patients with high baseline calprotectin concentrations (p = 0.036). However, patients with increasing calprotectin serum concentrations within the first week of ICU admission showed an improved overall survival (p = 0.009). Conclusions: In summary, serum calprotectin concentrations are significantly increased in critically ill patients with sepsis. High calprotectin concentrations at ICU admission predict long-term mortality risk, whereas increasing calprotectin concentrations are associated with a favorable long-term outcome.

1 April 2020 in JHEP Reports
Verified
Journal Article
Open access
SLSven Loosen
Sven Loosen
ABAnnemarie Breuer
Annemarie Breuer
FTFrank Tacke
Frank Tacke
JKJakob Nikolas Kather
Jakob Nikolas Kather
JGJoao Gorgulho
Joao Gorgulho
TLTom Lüdde
Tom Lüdde
Surgical resection is the only potentially curative therapy for patients with biliary tract cancer (BTC), but 5-year survival rates after tumor resection have remained below 30%, corroborating the need for better stratification tools to identify the ideal surgical candidates. The soluble urokinase plasminogen activator receptor (suPAR) represents a mediator of inflammation and has been associated with distinct types of cancer. In this study, we evaluated a potential role of suPAR as a novel biomarker in patients undergoing BTC resection. Tumor expression of uPAR was analyzed by immunohistochemistry in 108 BTC samples. Serum levels of suPAR were analyzed by ELISA in a training and validation cohort comprising a total of 117 patients with BTC and 76 healthy controls. High tumoral uPAR expression was associated with an adverse outcome after BTC resection. Accordingly, circulating levels of suPAR were significantly elevated in patients with BTC compared to healthy controls, as well as in patients with primary sclerosing cholangitis. Using a small training set, we established an optimal prognostic suPAR cut-off value of 3.72 ng/ml for patients with BTC. Importantly, preoperative suPAR serum levels above this cut-off value were associated with significantly impaired overall survival in both the training and validation cohort. Multivariate Cox-regression analysis including various clinicopathological parameters such as tumor stage, markers of inflammation and organ dysfunction, as well as tumor markers, revealed circulating suPAR levels as an independent prognostic marker following BTC resection. Finally, high preoperative suPAR levels were indicative of acute kidney injury after tumor resection. Circulating suPAR represents a previously unrecognized biomarker in patients with resectable BTC, which might help to preoperatively identify the ideal candidates for liver surgery. Surgical resection represents the only curative treatment option for patients with biliary tract cancer, but not all patients benefit to the same extent in terms of overall survival. Here, we provide evidence that serum levels of an inflammatory mediator (suPAR) are indicative of a patient's postoperative outcome and might thus help to identify the ideal surgical candidates.

Verified
Journal Article
Open access
PDF file
JBJonathan Frederik Brozat
Jonathan Frederik Brozat
NHNeval Harbalioğlu
Neval Harbalioğlu
PHPhilipp Hohlstein
Philipp Hohlstein
SJSamira Abu Jhaisha
Samira Abu Jhaisha
MPMaike Rebecca Pollmanns
Maike Rebecca Pollmanns
AKAlexander Koch
Alexander Koch
The kidney injury molecule (KIM)-1 is shed from proximal tubular cells in acute kidney injury (AKI), relaying tubular epithelial proliferation. Additionally, KIM-1 portends complex immunoregulation and is elevated after exposure to lipopolysaccharides. It thus may represent a biomarker in critical illness, sepsis, and sepsis-associated AKI (SA-AKI). To characterise and compare KIM-1 in these settings, we analysed KIM-1 serum concentrations in 192 critically ill patients admitted to the intensive care unit. Irrespective of kidney dysfunction, KIM-1 serum levels were significantly higher in patients with sepsis compared with other critical illnesses (191.6 vs. 132.2 pg/mL, p = 0.019) and were highest in patients with urogenital sepsis, followed by liver failure. Furthermore, KIM-1 levels were significantly elevated in critically ill patients who developed AKI within 48 h (273.3 vs. 125.8 pg/mL, p = 0.026) or later received renal replacement therapy (RRT) (299.7 vs. 146.3 pg/mL, p < 0.001). KIM-1 correlated with markers of renal function, inflammatory parameters, hematopoietic function, and cholangiocellular injury. Among subcomponents of the SOFA score, KIM-1 was elevated in patients with hyperbilirubinaemia (>2 mg/dL, p < 0.001) and thrombocytopenia ( 12 and APACHE II ≥ 20) on the day of admission, adjusting for relevant comorbidities, bilirubin, and platelet count. Additionally, KIM-1 in multivariate regression was able to predict sepsis in patients without prior (CKD) or present (AKI) kidney injury. Our study suggests that next to its established role as a biomarker in kidney dysfunction, KIM-1 is associated with sepsis, biliary injury, and critical illness severity. It thus may offer aid for risk stratification in these patients.

28 April 2022 in United European Gastroenterology Journal
Verified
Journal Article
Open access
JBJonathan Frederik Brozat
Jonathan Frederik Brozat
FHFrank Hanses
Frank Hanses
MHMartina Haelberger
Martina Haelberger
MSMelanie Stecher
Melanie Stecher
MDMichael Dreher
Michael Dreher
TGthe LEOSS study group
the LEOSS study group
Background and Objective: International registries have reported high mortality rates in patients with liver disease and COVID‐19. However, the extent to which comorbidities contribute to excess COVID‐19 mortality in cirrhosis is controversial.Methods: We used the multinational Lean European Open Survey on SARS‐CoV‐2‐infected patients (LEOSS) to identify patients with cirrhosis documented between March 2020 and March 2021, when the wild‐type and alpha variant were predominant. We compared symptoms, disease progression and mortality after propensity score matching (PSM) for age, sex, obesity, smoking status, and concomitant diseases. Mortality was also compared with that of patients with spontaneous bacterial peritonitis (SBP) without SARS‐CoV‐2 infection, a common bacterial infection and well‐described precipitator of acute‐on‐chronic liver failure.Results: Among 7096 patients with SARS‐CoV‐2 infection eligible for analysis, 70 (0.99%) had cirrhosis, and all were hospitalized. Risk factors for severe COVID‐19, such as diabetes, renal disease, and cardiovascular disease were more frequent in patients with cirrhosis. Case fatality rate in patients with cirrhosis was 31.4% with the highest odds of death in patients older than 65 years (43.6% mortality; odds ratio [OR] 4.02; p = 0.018), Child‐Pugh class C (57.1%; OR 4.00; p = 0.026), and failure of two or more organs (81.8%; OR 19.93; p = 0.001). After PSM for demographics and comorbidity, the COVID‐19 case fatality of patients with cirrhosis did not significantly differ from that of matched patients without cirrhosis (28.8% vs. 26.1%; p = 0.644) and was similar to the 28‐day mortality in a comparison group of patients with cirrhosis and SBP (33.3% vs. 31.5%; p = 1.000).Conclusions: In immunologically naïve patients with cirrhosis, mortality from wild‐type SARS‐CoV‐2 and the alpha variant is high and is largely determined by cirrhosis‐associated comorbidities and extrahepatic organ failure.

8 August 2020 in Diagnostics
Verified
Journal Article
Open access
PDF file
TWTheresa Wirtz
Theresa Wirtz
SLSven Loosen
Sven Loosen
LBLukas Buendgens
Lukas Buendgens
BKBerkan Kurt
Berkan Kurt
SJSamira Abu Jhaisha
Samira Abu Jhaisha
AKAlexander Koch
Alexander Koch
Background: Growth differentiation factor 8, GDF-8 (Myostatin), is a protein released by myocytes inhibiting muscle growth and differentiation. Serum concentrations of Myostatin can predict poor survival in different chronic diseases, but its role in critical illness and sepsis is obscure. Our aim was to investigate Myostatin levels as a potential prognostic biomarker in critically ill patients with sepsis. Methods: We therefore measured Myostatin serum concentrations in 165 critically ill patients (106 with sepsis, 59 without sepsis) upon admission to the medical intensive care unit (ICU), in comparison to 14 healthy controls. Results: Myostatin levels were significantly decreased in ICU patients compared to controls but did not differ in patients with or without sepsis. However, Myostatin concentrations were significantly lower in patients requiring mechanical ventilation and indicated a trend towards dependency of intravenous vasopressors. Interestingly, we observed a negative correlation between Myostatin levels and markers of systemic inflammation. Strikingly, overall survival (OS) was significantly impaired in patients with low Myostatin levels in all critically ill patients. Low Myostatin levels at baseline turned out as an independent prognostic marker for OS in multivariate Cox-regression analysis (HR: 0.433, 95% CI: 0.211–0.889, p = 0.023). Conclusions: In summary, serum Myostatin concentrations are significantly decreased in critically ill patients and associated with disease severity. Low Myostatin levels also identify a subgroup of ICU patients that are more likely to face an unfavorable clinical outcome in terms of OS.