PlasmaBlade versus Electrocautery for Deep Inferior Epigastric Perforator Flap Harvesting in Autologous Breast Reconstruction: A Comparative Clinical Outcome Study

(1) Background: DIEP-based breast reconstruction necessitates wide undermining at the abdominal donor site, creating large wound areas. Flap harvesting is usually conducted using electrosurgical dissection devices. This study sought to compare the clinical outcomes in patients after using the PEAK PlasmaBlade (PPB) versus monopolar electrocautery (MPE). (2) Methods: This retrospective cohort study included 128 patients with DIEP-based breast reconstruction. Patient characteristics and information on the postoperative course were collected and a comparative evaluation was conducted. (3) Results: The MPE group exhibited significantly (p* = 0.0324) higher abdominal drainage volume (351.11 ± 185.96 mL) compared to the PPB group (279.38 ± 183.38 mL). A subgroup analysis demonstrated that PPB significantly reduced postoperative wound fluid in patients with BMI > 30 kg/m2 (p* = 0.0284), without prior neoadjuvant chemotherapy (p** = 0.0041), and among non-smokers (p = 0.0046). Furthermore, postoperative pain was significantly (p**** < 0.0001) lower in the PPB cohort. (4) Conclusions: This study confirms the non-inferiority of the PEAK PlasmaBlade to conventional electrocautery for abdominal flap harvesting. The PPB demonstrated advantages, notably reduced drainage volume and lower postoperative pain levels. Recognizing patient subsets that benefit more from the PPB highlights the importance of personalized device selection based on patient characteristics.

Silicone implant surface microtopography modulates inflammation and tissue repair in capsular fibrosis

Excessive fibrous capsule formation around silicone mammary implants (SMI) involves immune reactions to silicone. Capsular fibrosis, a common SMI complication linked to host responses, worsens with specific implant topographies. Our study with 10 patients investigated intra- and inter-individually, reduced surface roughness effects on disease progression, wound responses, chronic inflammation, and capsular composition. The results illuminate the significant impact of surface roughness on acute inflammatory responses, fibrinogen accumulation, and the subsequent fibrotic cascade. The reduction of surface roughness to an average roughness of 4 μm emerges as a promising approach for mitigating detrimental immune reactions, promoting healthy wound healing, and curbing excessive fibrosis. The identified proteins adhering to rougher surfaces shed light on potential mediators of pro-inflammatory and pro-fibrotic processes, further emphasizing the need for meticulous consideration of surface design. The composition of the implant capsule and the discovery of intracapsular HSP60 expression highlight the intricate web of stress responses and immune activation that can impact long-term tissue outcomes.

Is It All about Surface Topography? An Intra-Individual Clinical Outcome Analysis of Two Different Implant Surfaces in Breast Reconstruction

The most common long-term complication of silicone breast implants (SMI) remains capsular fibrosis. The etiology of this exaggerated implant encapsulation is multifactorial but primarily induced by the host response towards the foreign material silicone. Identified risk factors include specific implant topographies. Of note, breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) has only been observed in response to textured surface implants. We hypothesize that reduction of SMI surface roughness causes less host response and, hence, better cosmetic outcomes with fewer complications for the patient. A total of 7 patients received the routinely used CPX^®4 breast expander (~60 µM Ra) and the novel SmoothSilk^® (~4 µM Ra), fixed prepectoral with a titanized mesh pocket and randomized to the left or right breast after bilateral prophylactic NSME (nipple-sparing mastectomy). We aimed to compare the postoperative outcome regarding capsule thickness, seroma formation, rippling, implant dislocation as well as comfortability and practicability. Our analysis shows that surface roughness is an influential parameter in controlling fibrotic implant encapsulation. Compared intra-individually for the first time in patients, our data confirm an improved biocompatibility with minor capsule formation around SmoothSilk^® implants with an average shell roughness of 4 µM and in addition an amplification of host response by titanized implant pockets.

Quantitative Proteomic Characterization of Foreign Body Response towards Silicone Breast Implants Identifies Chronological Disease-Relevant Biomarker Dynamics

The etiology of exaggerated fibrous capsule formation around silicone mammary implants (SMI) is multifactorial but primarily induced by immune mechanisms towards the foreign material silicone. The aim of this work was to understand the disease progression from implant insertion and immediate tissue damage response reflected in (a) the acute wound proteome and (b) the adsorption of chronic inflammatory wound proteins at implant surfaces. An intraindividual relative quantitation TMT-liquid chromatography-tandem mass spectrometry approach was applied to the profile wound proteome formed around SMI in the first five days post-implantation. Compared to plasma, the acute wound profile resembled a more complex composition comprising plasma-derived and locally differentially expressed proteins (DEPs). DEPs were subjected to a functional enrichment analysis, which revealed the dysregulation of signaling pathways mainly involved in immediate inflammation response and ECM turnover. Moreover, we found time-course variations in protein enrichment immediately post-implantation, which were adsorbed to SMI surfaces after 6-8 months. Characterization of the expander-adhesive proteome by a label-free approach uncovered a long-term adsorbed acute wound and the fibrosis-associated proteome. Our findings propose a wound biomarker panel for the early detection and diagnosis of excessive fibrosis that could potentially broaden insights into the characteristics of fibrotic implant encapsulation.

Donor-Site Morbidity and Quality of Life after Autologous Breast Reconstruction with PAP versus TMG Flap

The transverse myocutaneous gracilis (TMG) and the profunda artery perforator (PAP) flap are both safe choices for autologous breast reconstruction originating from the same donor region in the upper thigh. We aimed to compare the post-operative outcome regarding donor-site morbidity and quality of life. We included 18 patients who had undergone autologous breast reconstruction with a PAP flap (n = 27 flaps). Prospective evaluation of donor-site morbidity was performed by applying the same questionnaire that had already been established in a previous study evaluating TMG flap (n = 25 flaps) outcome, and results were compared. Comparison of the two patient groups showed equivalent results concerning patient-reported visibility of the donor-site scar and thigh symmetry. Still, the TMG group was significantly more satisfied with the scar (p = 0.015) and its position (p = 0.001). No difference was found regarding the ability to sit for prolonged periods. Donor-site wound complications were seen more frequently in the PAP group (29.6%) than in the TMG group (4.0%). Both groups expressed rather high satisfaction with their quality of life. Both flaps show minimal functional donor-site morbidity and high patient satisfaction. To minimize wound healing problems in PAP patients, thorough planning of the skin paddle is necessary.

Regulation of sensory perception and motor abilities by brain-specific action of chromatin remodeling factor CHD1

The ATP-dependent chromatin remodeling factor CHD1 (chromodomain-helicase-DNA binding protein 1) is involved in both the de novo assembly and the remodeling of chromatin. Recently, we discovered a crucial role of CHD1 in the incorporation of the histone variant H3.3 in the fly brain illustrated by widespread transcriptional upregulation and shortened lifespan in Chd1-mutant animals. Because many genes linked to sensory perception were dysregulated in Chd1-mutant heads, we studied the role of CHD1 in these processes. Here we show that Chd1-mutant flies have severe defects in their response behavior to olfactory and gustatory but not visual stimuli. Further analyses suggested that poor performance in gustatory response assays was caused by reduced motivation for foraging and feeding rather than defects in taste perception. Moreover, we show that shortened lifespan of Chd1-mutant flies is accompanied by indications of premature functional aging as suggested by defects in negative geotaxis and exploratory walking assays. The latter phenotype was rescued by neuronal re-expression of Chd1, while the olfactory defects were not. Interestingly, we found evidence for indirect regulation of the non-neuronal expression of odorant binding proteins (Obp) by neuronal expression of Chd1. Together, these results emphasize the crucial role of CHD1 activity controlling diverse neuronal processes thereby affecting healthy lifespan.

CHD1 controls H3.3 incorporation in adult brain chromatin to maintain metabolic homeostasis and normal lifespan

The ATP-dependent chromatin remodeling factor CHD1 is essential for the assembly of variant histone H3.3 into paternal chromatin during sperm chromatin remodeling in fertilized eggs. It remains unclear, however, if CHD1 has a similar role in normal diploid cells. Using a specifically tailored quantitative mass spectrometry approach, we show that Chd1 disruption results in reduced H3.3 levels in heads of Chd1 mutant flies. Chd1 deletion perturbs brain chromatin structure in a similar way as H3.3 deletion and leads to global de-repression of transcription. The physiological consequences are reduced food intake, metabolic alterations, and shortened lifespan. Notably, brain-specific CHD1 expression rescues these phenotypes. We further demonstrate a strong genetic interaction between Chd1 and H3.3 chaperone Hira. Thus, our findings establish CHD1 as a factor required for the assembly of H3.3-containing chromatin in adult cells and suggest a crucial role for CHD1 in the brain as a regulator of organismal health and longevity.

Role for Chromatin Remodeling Factor Chd1 in Learning and Memory

Precise temporal and spatial regulation of gene expression in the brain is a prerequisite for cognitive processes such as learning and memory. Epigenetic mechanisms that modulate the chromatin structure have emerged as important regulators in this context. While posttranslational modification of histones or the modification of DNA bases have been examined in detail in many studies, the role of ATP-dependent chromatin remodeling factors (ChRFs) in learning- and memory-associated gene regulation has largely remained obscure. Here we present data that implicate the highly conserved chromatin assembly and remodeling factor Chd1 in memory formation and the control of immediate early gene (IEG) response in the hippocampus. We used various paradigms to assess short-and long-term memory in mice bearing a mutated Chd1 gene that gives rise to an N-terminally truncated protein. Our data demonstrate that the Chd1 mutation negatively affects long-term object recognition and short- and long-term spatial memory. We found that Chd1 regulates hippocampal expression of the IEG early growth response 1 (Egr1) and activity-regulated cytoskeleton-associated (Arc) but not cFos and brain derived neurotrophic factor (Bdnf), because the Chd1-mutation led to dysregulation of Egr1 and Arc expression in naive mice and in mice analyzed at different stages of object location memory (OLM) testing. Of note, Chd1 likely regulates Egr1 in a direct manner, because chromatin immunoprecipitation (ChIP) assays revealed enrichment of Chd1 upon stimulation at the Egr1 genomic locus in the hippocampus and in cultured cells. Together these data support a role for Chd1 as a critical regulator of molecular mechanisms governing memory-related processes, and they show that this function involves the N-terminal serine-rich region of the protein.

Impact of the Chromatin Remodeling Factor CHD1 on Gut Microbiome Composition of Drosophila melanogaster

The composition of the intestinal microbiota of Drosophila has been studied in some detail in recent years. Environmental, developmental and host-specific genetic factors influence microbiome composition in the fly. Our previous work has indicated that intestinal bacterial load can be affected by chromatin-targeted regulatory mechanisms. Here we studied a potential role of the conserved chromatin assembly and remodeling factor CHD1 in the shaping of the gut microbiome in Drosophila melanogaster. Using high-throughput sequencing of 16S rRNA gene amplicons, we found that Chd1 deletion mutant flies exhibit significantly reduced microbial diversity compared to rescued control strains. Specifically, although Acetobacteraceae dominated the microbiota of both Chd1 wild-type and mutant guts, Chd1 mutants were virtually monoassociated with this bacterial family, whereas in control flies other bacterial taxa constituted ~20% of the microbiome. We further show age-linked differences in microbial load and microbiota composition between Chd1 mutant and control flies. Finally, diet supplementation experiments with Lactobacillus plantarum revealed that, in contrast to wild-type flies, Chd1 mutant flies were unable to maintain higher L. plantarum titres over time. Collectively, these data provide evidence that loss of the chromatin remodeler CHD1 has a major impact on the gut microbiome of Drosophila melanogaster.