Neutrophil-mediated Suppression of Influenza-induced Pathology Requires CD11b/CD18 (MAC-1).

Severe influenza virus infection can lead to life-threatening pathology through immune-mediated tissue damage. In various experimental models, this damage is dependent on T cells. There is conflicting evidence regarding the role of neutrophils in influenza-mediated pathology. Neutrophils are often regarded as cells causing tissue damage, but, in recent years, it has become clear that a subset of human neutrophils is capable of suppressing T cells, which is dependent on macrophage-1 antigen (CD11b/CD18). Therefore, we tested the hypothesis that immune suppression by neutrophils can reduce T cell-mediated pathology after influenza infection. Wild-type (WT) and CD11b-/- mice were infected with A/HK/2/68 (H3N2) influenza virus. Disease severity was monitored by weight loss, leukocyte infiltration, and immunohistochemistry. We demonstrated that CD11b-/- mice suffered increased weight loss compared with WT animals upon infection with influenza virus. This was accompanied by increased pulmonary leukocyte infiltration and lung damage. The exaggerated pathology in CD11b-/- mice was dependent on T cells, as it was reduced by T cell depletion. In addition, pathology in CD11b-/- mice was accompanied by higher numbers of T cells in the lungs early during infection compared with WT mice. Importantly, these differences in pathology were not associated with an increased viral load, suggesting that pathology was immune-mediated rather than caused by virus-induced damage. In contrast to adoptive transfer of CD11b-/- neutrophils, a single adoptive transfer of WT neutrophils partly restored protection against influenza-induced pathology, demonstrating the importance of neutrophil CD11b/CD18. Our data show that neutrophil CD11b/CD18 limits pathology in influenza-induced, T cell-mediated disease.

An increase in myeloid cells after severe injury is associated with normal fracture healing: a retrospective study of 62 patients with a femoral fracture.

Background and purpose-Nonunion is common in femoral fractures. Previous studies suggested that the systemic immune response after trauma can interfere with fracture healing. Therefore, we investigated whether there is a relation between peripheral blood cell counts and healing of femur fractures. Patients and methods-62 multi-trauma patients with a femoral fracture presenting at the University Medical Centre Utrecht between 2007 and 2013 were retrospectively included. Peripheral blood cell counts from hematological analyzers were recorded from the 1st through the 14th day of the hospital stay. Generalized estimating equations were used to compare outcome groups. Results-12 of the 62 patients developed nonunion of the femoral fracture. The peripheral blood-count curves of total leukocytes, neutrophils, monocytes, lymphocytes, and platelets were all statistically significantly lower in patients with nonunion, coinciding with significantly higher CRP levels during the first 2 weeks after trauma in these patients. Interpretation-Patients who developed femoral nonunion after major trauma demonstrated lower numbers of myeloid cells in the peripheral blood than patients with normal fracture healing. This absent rise of myeloid cells seems to be related to a more severe post-traumatic immune response.

Neutrophils contribute to fracture healing by synthesizing fibronectin+ extracellular matrix rapidly after injury.

The role of inflammatory cells in bone regeneration remains unclear. We hypothesize that leukocytes contribute to fracture healing by rapidly synthesizing an "emergency extracellular matrix (ECM)" before stromal cells infiltrate the fracture hematoma (FH) and synthesize the eventual collagenous bone tissue. 53 human FHs were isolated at different time points after injury, ranging from day 0 until day 23 after trauma and stained using (immuno)histochemistry. FHs isolated within 48 h after injury contained fibronectin(+) ECM, which increased over time. Neutrophils within the early FHs stained positive for cellular fibronectin and neutrophil derived particles were visible within the fibronectin(+) ECM. Stromal cells appeared at day 5 after injury or later and collagen type I birefringent fibrils could be identified during the second week after injury. Our study suggests that neutrophils contribute to bone regeneration by synthesizing an "emergency ECM" before stromal cells infiltrate the FH and synthesize the eventual bone tissue.

Systematic review and meta-analysis determining the effect of implemented COVID-19 guidelines on surgical oncology volumes and clinical outcomes.

BACKGROUND: To provide for Coronavirus Disease 2019 (COVID-19) healthcare capacity, (surgical oncology) guidelines were established, forcing to alter the timing of performing surgical procedures. It is essential to determine whether these guidelines have led to disease progression. This study aims to give an insight into the number of surgical oncology procedures performed during the pandemic and provide information on short-term clinical outcomes. MATERIALS AND METHODS: A systematic literature search was performed on all COVID-19 articles including operated patients, published before March 21, 2022. Meta-analysis was performed to visualize the number of performed surgical oncology procedures during the pandemic compared to the pre-pandemic period. Random effects models were used for evaluating short-term clinical outcomes. RESULTS: Twenty-four studies containing 6762 patients who underwent a surgical oncology procedure during the pandemic were included. The number of performed surgical procedures for an oncological pathology decreased (-26.4%) during the pandemic. The number of performed surgical procedures for breast cancer remained stable (+0.3%). Moreover, no difference was identified in the number of ≥T2 (OR 1.00, P = 0.989), ≥T3 (OR 0.95, P = 0.778), ≥N1 (OR 1.01, P = 0.964) and major postoperative complications (OR 1.55, P = 0.134) during the pandemic. CONCLUSION: The number of performed surgical oncology procedures during the COVID-19 pandemic decreased. In addition, the number of performed surgical breast cancer procedures remained stable. Oncological staging and major postoperative complications showed no significant difference compared to pre-pandemic practice. During future pandemics, the performed surgical oncology practice during the first wave of the COVID-19 pandemic seems appropriate for short-term results.

Quality of life in patients with IBD during the COVID-19 pandemic in the Netherlands.

OBJECTIVE: COVID-19 has put a strain on regular healthcare worldwide. For inflammatory bowel disease (IBD), gastrointestinal surgeries were postponed and changes in treatment and diagnostic procedures were made. As abrupt changes in treatment regimens may result in an increased morbidity and consequent well-being of patients with IBD, the aim of this study was to determine the effect of the COVID-19 pandemic on health-related quality of life (HRQoL) in patients with IBD. DESIGN: All patients with IBD who completed both Inflammatory Bowel Disease Questionnaire (IBDQ) and 36-Item Short Form Health Survey (SF-36) questionnaire between 31 August and 13 September 2020 were included in our cohort study. The primary end point was to determine the HRQoL in patients with IBD, measured by the IBDQ and SF-36 questionnaire. The secondary end point was determining which factors influence the HRQoL in patients with IBD. RESULTS: 582 patients with IBD filled in the IBDQ and SF-36 questionnaire. The HRQoL in our study population was low according to the questionnaires on both physical and mental subscales. In addition, multivariate analysis showed that increased age, female sex and patients who underwent surgery had a significantly lower HRQoL, most frequently on the physical domains in both questionnaires. CONCLUSION: Patients with IBD had an overall low HRQoL during the COVID-19 pandemic. Furthermore, older patients, women and patients who underwent surgical procedures had the lowest physical HRQoL.

Buried penis after newborn circumcision.

PURPOSE: Buried penis may develop after circumcision, mostly during infancy, presumably due to peripubic fat. A surgical approach may be recommended for psychological benefits to patients and parents, and because it is believed that this condition will not improve on its own with time. The aim of this study was to assess the natural history of buried penis after newborn circumcision. MATERIALS AND METHODS: During a routine visit to the pediatrician infants with buried penis were assessed by a single pediatric surgeon between January 2004 and June 2007. In December 2007 all of these children were reexamined by the same pediatric surgeon and the natural growth of the genitalia was analyzed. RESULTS: A total of 88 infants were enrolled in the study. When they were first examined they were 3 to 6 months old (mean 3.3). In December 2007, after reexamination, patients were divided into groups based on age, including those younger than 1 year (14 patients), 1 to 3 years (59) and older than 3 years (15). The aspect of the genitalia was evaluated by the same pediatric surgeon for each patient. Buried penis was noted in 14 of 14 patients younger than 1 year (100%), 19 of 59 patients 1 to 3 years old (32.2%) and 1 of 15 patients older than 3 years (6.7%). CONCLUSIONS: Buried penis after newborn circumcision is not permanent. As infants get older, and after beginning to walk, the appearance usually turns out to be normal. This resolution may be due to growth and/or maturation alone. Based on our results, we do not recommend surgery for buried penis in children younger than 3 years.

Serum from the Human Fracture Hematoma Contains a Potent Inducer of Neutrophil Chemotaxis.

A controlled local inflammatory response is essential for adequate fracture healing. However, the current literature suggests that local and systemic hyper-inflammatory conditions after major trauma induce increased influx of neutrophils into the fracture hematoma (FH) and impair bone regeneration. Inhibiting neutrophil chemotaxis towards the FH without compromising the hosts' defense may therefore be a target of future therapies that prevent impairment of fracture healing after major trauma. We investigated whether chemotaxis of neutrophils towards the FH could be studied in vitro. Moreover, we determined whether chemotaxis of neutrophils towards the FH was mediated by the CXCR1, CXCR2, FPR, and C5aR receptors. Human FHs were isolated during an open reduction internal fixation (ORIF) procedure within 3 days after trauma and spun down to obtain the fracture hematoma serum. Neutrophil migration towards the FH was studied using Ibidi™ Chemotaxis3D µ-Slides and image analysis of individual neutrophil tracks was performed. Our study showed that the human FH induces significant neutrophil chemotaxis, which was not affected by blocking CXCR1 and CXCR2. In contrast, neutrophil chemotaxis towards the FH was significantly inhibited by chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS), which blocks FPR and C5aR. Blocking only C5aR with CHIPSΔ1F also significantly inhibited neutrophil chemotaxis towards the FH. Our finding that neutrophil chemotaxis towards the human FH can be blocked in vitro using CHIPS may aid the development of therapies that prevent impairment of fracture healing after major trauma.

Neutrophils Inhibit Synthesis of Mineralized Extracellular Matrix by Human Bone Marrow-Derived Stromal Cells In Vitro.

Although controlled local inflammation is essential for adequate bone regeneration, several studies have shown that hyper-inflammatory conditions after major trauma are associated with impaired fracture healing. These hyper-inflammatory conditions include the trauma-induced systemic inflammatory response to major injury, open fractures, and significant injury to the surrounding soft tissues. The current literature suggests that increased or prolonged influx of neutrophils into the fracture hematoma may mediate impairment of bone regeneration after hyper-inflammatory conditions. The underlying mechanism remains unclear. We hypothesize that high neutrophil numbers inhibit synthesis of mineralized extracellular matrix (ECM) by bone marrow stromal cells (BMSCs). We therefore studied the effect of increasing concentrations of neutrophils on ECM synthesis by human BMSCs in vitro. Moreover, we determined how high neutrophil concentrations affect BMSC cell counts, as well as BMSC osteogenic activity determined by alkaline phosphatase (ALP) expression and ALP activity. Co-culture of BMSCs with neutrophils induced a 52% decrease in BMSC cell count (p < 0.01), a 64% decrease in the percentage of ALP+ cells (p < 0.001), a 28% decrease in total ALP activity (p < 0.01), and a significant decrease in the amount of mineralized ECM [38% decrease after 4 weeks (p < 0.05)]. Co-cultures with peripheral blood mononuclear cells and neutrophils within transwells did not induce a significant decrease in ALP activity. In conclusion, our data shows that a decreased amount of mineralized ECM became synthesized by BMSCs, when they were co-cultured with high neutrophil concentrations. Moreover, high neutrophil concentrations induced a decrease in BMSC cell counts and decreased ALP activity. Clarifying the underlying mechanism may contribute to development of therapies that augment bone regeneration or prevent impaired fracture healing after hyper-inflammatory conditions.

Impaired bone healing in multitrauma patients is associated with altered leukocyte kinetics after major trauma.

Animal studies have shown that the systemic inflammatory response to major injury impairs bone regeneration. It remains unclear whether the systemic immune response contributes to impairment of fracture healing in multitrauma patients. It is well known that systemic inflammatory changes after major trauma affect leukocyte kinetics. We therefore retrospectively compared the cellular composition of peripheral blood during the first 2 weeks after injury between multitrauma patients with normal (n=48) and impaired (n=32) fracture healing of the tibia. The peripheral blood-count curves of leukocytes, neutrophils, monocytes, and thrombocytes differed significantly between patients with normal and impaired fracture healing during the first 2 weeks after trauma (P-values were 0.0122, 0.0083, 0.0204, and <0.0001, respectively). Mean myeloid cell counts were above reference values during the second week after injury. Our data indicate that leukocyte kinetics differ significantly between patients with normal and impaired fracture healing during the first 2 weeks after major injury. This finding suggests that the systemic immune response to major trauma can disturb tissue regeneration.