Björn B. Hofmann

Dr. Björn B. Hofmann

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Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

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

Representative Publications

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4 February 2019 in Scientific Reports
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Journal Article
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JBJana D. Braun
Jana D. Braun
DPDiego O. Pastene
Diego O. Pastene
ABAnnette Breedijk
Annette Breedijk
ARAngelica Rodriguez
Angelica Rodriguez
BHBjörn B. Hofmann
Björn B. Hofmann
TAThomas Albrecht
Thomas Albrecht
Although methylglyoxal (MGO) has emerged as key mediator of diabetic microvascular complications, the influence of MGO on the vascular transcriptome has not thoroughly been assessed. Since diabetes is associated with low grade inflammation causing sustained nuclear factor-kappa B (NF-κB) activation, the current study addressed 1) to what extent MGO changes the transcriptome of human umbilical vein endothelial cells (HUVECs) exposed to an inflammatory milieu, 2) what are the dominant pathways by which these changes occur and 3) to what extent is this affected by carnosine, a putative scavenger of MGO. Microarray analysis revealed that exposure of HUVECs to high MGO concentrations significantly changes gene expression, characterized by prominent down-regulation of cell cycle associated genes and up-regulation of heme oxygenase-1 (HO-1). KEGG-based pathway analysis identified six significantly enriched pathways of which the p53 pathway was the most affected. No significant enrichment of inflammatory pathways was found, yet, MGO did inhibit VCAM-1 expression in Western blot analysis. Carnosine significantly counteracted MGO-mediated changes in a subset of differentially expressed genes. Collectively, our results suggest that MGO initiates distinct transcriptional changes in cell cycle/apoptosis genes, which may explain MGO toxicity at high concentrations. MGO did not augment TNF-α induced inflammation.

29 November 2023 in Neurocritical Care
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Journal Article
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BHBjörn B. Hofmann
Björn B. Hofmann
DDDaniel M. Donaldson
Daniel M. Donaldson
MNMilad Neyazi
Milad Neyazi
YAYousef Abusabha
Yousef Abusabha
KBKerim Beseoglu
Kerim Beseoglu
MSMuhammad Sajjad
Muhammad Sajjad
Background: Despite intensive research on preventing and treating vasospasm and delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage (aSAH), mortality and morbidity rates remain high. Early brain injury (EBI) has emerged as possibly the major significant factor in aSAH pathophysiology, emphasizing the need to investigate EBI-associated clinical events for improved patient management and decision-making. This study aimed to identify early clinical and radiological events within 72 h after aSAH to develop a conclusive predictive EBI score for clinical practice. Methods: This retrospective analysis included 561 consecutive patients with aSAH admitted to our neurovascular center between 01/2014 and 09/2022. Fourteen potential predictors occurring within the initial 72 h after hemorrhage were analyzed. The modified Rankin Scale (mRS) score at 6 months, discretized to three levels (0–2, favorable; 3–5, poor; 6, dead), was used as the outcome variable. Univariate ordinal regression ranked predictors by significance, and forward selection with McFadden’s pseudo-R2 determined the optimal set of predictors for multivariate proportional odds logistic regression. Collinear parameters were excluded, and fivefold cross-validation was used to avoid overfitting. Results: The analysis resulted in the Subarachnoid Hemorrhage Associated Early Brain Injury Outcome Prediction score (SHELTER-score), comprising seven clinical and radiological events: age (0–4 points), World Federation of Neurosurgical Societies (0–2.5 points), cardiopulmonary resuscitation (CPR) (2 points), mydriasis (1–2 points), midline shift (0.5–1 points), early deterioration (1 point), and early ischemic lesion (2 points). McFadden’s pseudo-R2 = 0.339, area under the curve for death or disability 0.899 and 0.877 for death. A SHELTER-score below 5 indicated a favorable outcome (mRS 0–2), 5–6.5 predicted a poor outcome (mRS 3–5), and ≥ 7 correlated with death (mRS 6) at 6 months. Conclusions: The novel SHELTER-score, incorporating seven clinical and radiological features of EBI, demonstrated strong predictive performance in determining clinical outcomes. This scoring system serves as a valuable tool for neurointensivists to identify patients with poor outcomes and guide treatment decisions, reflecting the great impact of EBI on the overall outcome of patients with aSAH.

3 June 2021 in American Journal of Neuroradiology
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Journal Article
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BHBjörn B. Hofmann
Björn B. Hofmann
IFIgor Fischer
Igor Fischer
AEAdrian Engel
Adrian Engel
KJKai Jannusch
Kai Jannusch
DDD.M. Donaldson
D.M. Donaldson
CRChristian Rubbert
Christian Rubbert
BACKGROUND AND PURPOSE: Impairment of tissue oxygenation caused by inhomogeneous microscopic blood flow distribution, the so-called capillary transit time heterogeneity, is thought to contribute to delayed cerebral ischemia after aneurysmal SAH but has so far not been systematically evaluated in patients. We hypothesized that heterogeneity of the MTT, derived from CTP parameters, would give insight into the clinical course of patients with aneurysmal SAH and may identify patients at risk of poor outcome. MATERIALS AND METHODS: We retrospectively analyzed the heterogeneity of the MTT using the coefficient of variation in CTP scans from 132 patients. A multivariable logistic regression model was used to model the dichotomized mRS outcome. Linear regression was used to eliminate variables with high linear dependence. T tests were used to compare the means of 2 groups. Furthermore, the time of the maximum coefficient of variation for MTT after bleeding was evaluated for correlation with the mRS after 6 months. RESULTS: On average, each patient underwent 5.3 CTP scans during his or her stay. Patients with high coefficient of variation for MTT presented more often with higher modified Fisher (P = .011) and World Federation of Neurosurgical Societies grades (P = .014). A high coefficient of variation for MTT at days 3–21 after aneurysmal SAH correlated significantly with a worse mRS score after 6 months (P = .016). We found no correlation between the time of the maximum coefficient of variation for MTT after bleeding and the patients’ outcomes after 6 months (P = .203). CONCLUSIONS: Heterogeneity of MTT in CTP after aneurysmal SAH correlates with the patients’ outcomes. Because the findings are in line with the pathophysiologic concept of the capillary transit time heterogeneity, future studies should seek to verify the coefficient of variation for MTT as a potential imaging biomarker for outcome.

10 August 2023 in Journal of Clinical Medicine
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Journal Article
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CKCihat Karadag
Cihat Karadag
MKMarcel Kamp
Marcel Kamp
IFIgor Fischer
Igor Fischer
HBHieronymus D. Boogaarts
Hieronymus D. Boogaarts
KBKerim Beseoglu
Kerim Beseoglu
BHBjörn B. Hofmann
Björn B. Hofmann
The temporalis muscle area (TMA) has been proclaimed as a surrogate parameter for estimating skeletal muscle mass. Pilot studies in Asian populations suggested temporal muscle thickness (TMT) and TMA as prognostic factors for neurological outcomes in aneurysmal subarachnoid hemorrhage (aSAH) patients. This study aimed to validate these findings in a larger European patient cohort. We retrospectively analyzed age, sex, aneurysm location, treatment, World Federation of Neurosurgical Societies (WFNS) grade, Fisher score, and modified Rankin Score (mRS) at six months in patients with aSAH. TMT and TMA measurements were obtained from initial native CT scans. Logistic regression with the dichotomized six-month mRS as the outcome incorporating TMT, weighted average of TMT, or TMA as predictors was performed. Of the included 478 patients, 66% were female, the mean age was 56, and 48% of patients had an mRS of three to six after six months. The mean TMT at the level of the Sylvian fissure was 5.9 (±1.7) mm in males and 4.8 (±1.8) mm in females. The mean TMA was 234.5 (±107.9) mm2 in females and 380 (±134.1) mm2 in males. WFNS grade (p < 0.001), Fisher score (p < 0.001), and age (p < 0.05) correlated significantly with the mRS after six months. No correlation was found between mRS after six months and the TMT at the Sylvian fissure (p = 0.3), the weighted average of TMT (p = 0.1), or the TMA (p = 0.1). In this central European patient cohort of 478 individuals, no significant associations were found between TMT/TMA and neurological outcomes following aSAH. Further prospective studies in diverse patient populations are necessary to determine the prognostic value of TMA and TMT in aSAH patients.

17 February 2023 in Neurocritical Care
Verified
Journal Article
Open access
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BHBjörn B. Hofmann
Björn B. Hofmann
DDDaniel M. Donaldson
Daniel M. Donaldson
IFIgor Fischer
Igor Fischer
CKCihat Karadag
Cihat Karadag
MNMilad Neyazi
Milad Neyazi
KBKerim Beseoglu
Kerim Beseoglu
Background: Early computed tomography perfusion (CTP) is frequently used to predict delayed cerebral ischemia following aneurysmatic subarachnoid hemorrhage (aSAH). However, the influence of blood pressure on CTP is currently controversial (HIMALAIA trial), which differs from our clinical observations. Therefore, we aimed to investigate the influence of blood pressure on early CTP imaging in patients with aSAH. Methods: We retrospectively analyzed the mean transit time (MTT) of early CTP imaging within 24 h after bleeding prior to aneurysm occlusion with respect to blood pressure shortly before or after the examination in 134 patients. We correlated the cerebral blood flow with the cerebral perfusion pressure in the case of patients with intracranial pressure measurement. We performed a subgroup analysis of good-grade (World Federation of Neurosurgical Societies [WFNS] I–III), poor-grade (WFNS IV–V), and solely WFNS grade V aSAH patients. Results: Mean arterial pressure (MAP) significantly correlated inversely with the mean MTT in early CTP imaging (R = − 0.18, 95% confidence interval [CI] − 0.34 to − 0.01, p = 0.042). Lower mean blood pressure was significantly associated with a higher mean MTT. Subgroup analysis revealed an increasing inverse correlation when comparing WFNS I–III (R = − 0.08, 95% CI − 0.31 to 0.16, p = 0.53) patients with WFNS IV–V (R = − 0.2, 95% CI − 0.42 to 0.05, p = 0.12) patients, without reaching statistical significance. However, if only patients with WFNS V are considered, a significant and even stronger correlation between MAP and MTT (R = − 0.4, 95% CI − 0.65 to 0.07, p = 0.02) is observed. In patients with intracranial pressure monitoring, a stronger dependency of cerebral blood flow on cerebral perfusion pressure is observed for poor-grade patients compared with good-grade patients. Conclusions: The inverse correlation between MAP and MTT in early CTP imaging, increasing with the severity of aSAH, suggests an increasing disturbance of cerebral autoregulation with the severity of early brain injury. Our results emphasize the importance of maintaining physiological blood pressure values in the early phase of aSAH and preventing hypotension, especially in patients with poor-grade aSAH.

12 October 2023 in Neurosurgery
Verified
Journal Article
Closed access
BHBjörn B. Hofmann
Björn B. Hofmann
IFIgor Fischer
Igor Fischer
MNMilad Neyazi
Milad Neyazi
CKCihat Karadag
Cihat Karadag
DDDaniel M. Donaldson
Daniel M. Donaldson
DHDaniel Hänggi
Daniel Hänggi
BACKGROUND AND OBJECTIVES: In patients suffering from aneurysmal subarachnoid hemorrhage (aSAH), the optimal time to determine the World Federation of Neurosurgical Societies (WFNS) score remains controversial because of possible confounding factors. Goals of this study were (1) to analyze the most sensitive timepoint to determine the WFNS score in patients with aSAH and (2) to evaluate the impact of initial native computed tomography (CT) imaging on reducing the mismatch of “false poor grade” patients. METHODS: We retrospectively analyzed daily WFNS scores from admission until day 7 in 535 aSAH patients and evaluated their predictive value for the modified Rankin Scale at discharge and 6 months postbleeding. Patients with an initial WFNS score of IV–V who showed improvement to a WFNS score of I–II within the first 7 days (even short-term) were defined as “false poor grade” patients. We tried to identify the “false poor grade” patients using parameters of the initial native CT imaging. RESULTS: Later determination of the WFNS score (day 1 vs 7; pseudo-R2 = 0.13 vs 0.21) increasingly improved its predictive value for neurological outcome at discharge (P < .001). We identified 39 “false poor grade” patients who had significantly better outcomes than “real poor grade” patients (N = 220) (modified Rankin Scale-discharge: 0-2, 56% vs 1%, P < .001; 3-5: 41% vs 56%, P = .12; 6: 3% vs 43%, P < .001). “False poor grade” patients differed significantly in initial CT parameters. A predictive model called “initial CT WFNS” (ICTWFNS) was developed, incorporating SEBES, Hijdra score, and LeRoux score (sensitivity = 0.95, specificity = 0.84, accuracy = 0.859, F1 = 0.673). ICTWFNS scores of ≤4.6 classified patients as “false poor grade.” CONCLUSION: The initial WFNS score may misclassify a subgroup of patients with aSAH as poor grade, which can be avoided by later determination of the WFNS score, at days 3–4 losing its usefulness. Alternatively, the initial WFNS score can be improved in its predictive value, especially in poor-grade patients, using criteria from the initial native CT imaging, such as the Hijdra, LeRoux, and Subarachnoid Hemorrhage Early Brain Edema score, combined in the ICTWFNS score with even higher predictive power.