Stem cells represent the regenerative capacity of our bodies; hence, it is essential for these cells to interact with the intrinsic and extrinsic environments, including nutritional components. Stem cells receive the nutritional elements as signal molecules that transmit certain messages to the cell epigenome, leading to cell differentiation. Such an effect could be similarly induced using several epigenetic modifiers. The influence of nutritional elements and contaminants on differentiation were demonstrated on embryonic stem cells during the embryonic development, as well as through in vitro studies. Similar evidence can be illustrated for adult stem cells in laboratory experiments. The interaction between nutrition and epigenetic can exert their effects on stem cell plasticity and differentiation, which may help in maintaining our health status and help in tissue regeneration after disease. This chapter includes an overview of the interaction between nutrition and stem cells through epigenetic mechanisms.

The skin is the biggest organ in the body and the organ that interacts directly with the environment. As a result, the skin is susceptible to numerous challenges that could result in injury or burn. The intricate interplay between different cell types, growth factors, mediators, chemokines, cytokines, neurovasculature, and the extracellular matrix is crucial for the healing of skin wounds. Additionally, the complex synchronization of several distinct cell types, in orderly phases, is necessary for skin restoration. The dermis is the outer impermeable layer of healthy skin that protects the body from its surroundings. Sebaceous glands, sweat glands, and hair follicles are all in the dermis. The dermis gives the skin strength, nutrition, and immunity and is abundant in the extracellular matrix and vascular channels. The dermis is supported by subcutaneous adipose tissue, which serves as an energy store. Moreover, it provides the dermis with growth factors continuously. Each layer also has resident immune cells that are continually scanning the skin for injury. With the use of several skin substitutes, skin healing success rates for different injuries have dramatically risen.

Have you ever thought about how our body compensates for lost cells? Have you heard about a new management line for several diseases using so-called stem cells? You may have heard about some pa<ents being defrauded with claims of stem cell therapy. 

When these magical cells and their therapeutic ability were discovered, many researchers and doctors believed that we found a cure for cureless conditions. Stem cells have amazing abilities to differentiate into various cells of the body, which is an indisputable fact, replacing damaged tissues in a manner similar to human spare parts. Thus, a new branch of medicine known as regenerative medicine has been emerged. The challenge is to harness these cells to respond adequately to the differentiation triggers. Also, the development of the protocols to introduce these cells into the body is a complex process. The mistake that a few medicals made was to rush the use of stem cells before establishing the conditions for treatment, including laboratory experiments and studies on experimental animals and groups of patients. These validations are required for licensing these cells as a medical treatment.

This book aims at providing basic information about stem cells and regenerative medicine from their scientific sources. In addition, the book highlights the current clinical studies, as well as future trends in this field.

الملخص العربى

هل فكرت يوما كيف يعوض جسمنا خلاياه المفقودة؟ هل سمعت عن طريقة جديدة للتعامل مع العديد والعديد من الأمراض باستخدام ما يسمي بالخلايا الجذعية؟ ربما تكون قد سمعت عن بعض المرضى الذين تعرضوا للاحتيال بمزاعم العلاج بتلك الخلايا.

عند اكتشاف هذه الخلايا السحرية وقدرتها العلاجية٬ ظن الكثير من الباحثين والأطباء أنه قد توصلنا الى علاج لكل ما لا علاج له. فلهذه الخلايا قدرات مذهلة للتحور الي مختلف خلايا الجسم٬ وهذه حقيقة لا خلاف عليها٬ وبالتالى تعويض الأنسجة التالفة فيما يشبه قطع الغيار البشرية٬ مما أدي إلى ظهور فرع جديد من فروع الطب يعرف باسم الطب التجديدى. ولكن المشكلة تكمن في ترويض هذه الخلايا بحيث تستجيب لعملية التحور بدون إفراط ولا تفريط. كما أن وضع البروتوكولات لإدخال هذه الخلايا إلى الجسم هى عملية معقدة. وكان الخطأ الذي وقع فيه بعض الأطباء هو التعجل باستخدام الخلايا الجذعية قبل تحقيق شروط العلاج من تجارب معملية ودراسات علي حيوانات التجارب وعلي مجموعات من المرضى٬ وصولا إلى ترخيص هذه الخلايا كعلاج طبى.  

يهدف هذا الكتاب إلى تقديم المعلومات الأساسية عن الخلايا الجذعية والطب التجديدى من مصادرها العلمية، وصولا الى الدراسات الإكلينيكية، وكذلك الاتجاهات المستقبلية فى هذا المجال.

BACKGROUND: As several recent studies have shown low mortality rates in burn injury induced ARDS early (≤7 days) after the burn, the Berlin criteria for the ARDS diagnosis in this setting may be disputed. Related to this issue, the present study investigated the incidence, trajectory and risk factors of early Acute Respiratory Distress Syndrome (ARDS) and outcome in burn patients, as per the Berlin criteria, along with the concurrent prevalence and influence of inhalation injury, and ventilator-acquired pneumonia (VAP).

METHODS: Over a 2.5-year period, burn patients with Total Burn Surface Area (TBSA) exceeding 10% admitted to a national burn center were included. The subgroup of interest comprised patients with more than 48 h of ventilatory support. This group was assessed for ARDS, inhalation injury, and VAP.

RESULTS: Out of 292 admissions, 62 sustained burns > 10% TBSA. Of these, 28 (45%) underwent ventilatory support for over 48 h, almost all, 24 out of 28, meeting the criteria for ARDS early, within 7 days post-injury and with a P_aO₂/F_iO₂ (PF) rat_io nadir at day 5. The mortality rate for this early ARDS group was under 10%, regardless of PF ratios (mean TBSA% 34,8%). Patients with concurrent inhalation injury and early ARDS showed significantly lower PF ratios (p < 0.001), and higher SOFA scores (p = 0.004) but without impact on mortality. Organ failure, indicated by SOFA scores, peaked early (day 3) and declined in the first week, mirroring PF ratio trends (p < 0.001).

CONCLUSIONS: The low mortality associated with early ARDS in burn patients in this study challenges the Berlin criteria's for the early ARDS diagnosis, which for its validity relies on that higher mortality is linked to worsening PF ratios. The finding suggests alternative mechanisms, leading to the early ARDS diagnosis, such as the significant impact of inhalation injury on early PF ratios and organ failure, as seen in this study. The concurrence of early organ failure with declining PF ratios, supports, as expected, the hypothesis of trauma-induced inflammation/multi-organ failure mechanisms contributing to early ARDS. The study highlights the complexity in differentiating between the contributions of inhalation injury to early ARDS and the related organ dysfunction early in the burn care trajectory. The Berlin criteria for the ARDS diagnosis may not be fully applicable in the burn care setting, where the low mortality significantly deviates from that described in the original Berlin ARDS criteria publication but is as expected when considering the actual not very extensive burn injury sizes/Baux scores as in the present study.

Background: Bladder cancer (BC) has a particular importance in Egyptian patients due to aggressive behavior and absence of prognostic markers. Objective: To evaluate the expression of gene and protein expression of HER2 and epidermal growth factor (EGFR) in Egyptian patients with BC and ultimately to investigate their clinical implication and prognostic significance. Material and methods: The study was carried out on 46 patients with urothelial bladder BC. Tissue were obtained from transurethral resection (N = 22) and radical cystectomy (N = 24) specimens. The original hematoxylin and eosin slides were re-evaluated and the formalin fixed, paraffin-embedded (FFPE) tissues which had sufficient tumor tissue (&gt;75%) and minimal or absent tumor necrosis were selected for immunohistochemistry (IHC) and RNA extraction. Furthermore, five control biopsies were obtained from patients with cystitis. Follow-up data were retrieved from the medical records which included the treatment regimen, disease recurrence and/or progression, and survival. Results: EGFR and HER2 protein were overexpressed in 35% and 46% of patients respectively. EGFR was correlated with the tumor size, grade and pathological stage, with a similar trend for HER2. The recurrence rate was higher in patients with expression of any of the markers. Gene expression was significantly higher (10.6-folds) for EGFR and (21-folds) for HER2 in patients with BC in comparison to control patients. Survival analysis showed lower median disease-free survival in association with HER2 protein overexpression. Conclusions: Our data highlighted the prognostic significance of EGFR and HER in BC and proposed their possible use as predictive markers and potential therapeutic targets.

To investigate if donor and recipient site morbidity (healing time and cosmesis) could be reduced by a novel, modified split-thickness skin grafting (STSG) technique using a dermal component in the STSG procedure (DG). The STSG technique has been used for 150 years in surgery with limited improvements. Its drawbacks are well known and relate to donor site morbidity and recipient site cosmetic shortcomings (especially mesh patterns, wound contracture, and scarring). The Dermal graft technique (DG) has emerged as an interesting alternative, which reduces donor site morbidity, increases graft yield, and has the potential to avoid the mesh procedure in the STSG procedure due to its elastic properties. A prospective, dual-centre, intra-individual controlled comparison study. Twenty-one patients received both an unmeshed dermis graft and a regular 1:1.5 meshed STSG. Aesthetic and scar assessments were done using The Patient and Observer Scar Assessment Scale (POSAS) and a Cutometer Dual MPA 580 on both donor and recipient sites. These were also examined histologically for remodelling and scar formation. Dermal graft donor sites and the STSG donor sites healed in 8 and 14 days, respectively (p < 0.005). Patient-reported POSAS showed better values for colour for all three measurements, i.e., 3, 6, and 12 months, and the observers rated both vascularity and pigmentation better on these occasions (p < 0.01). At the recipient site, (n = 21) the mesh patterns were avoided as the DG covered the donor site due to its elastic properties and rendered the meshing procedure unnecessary. Scar formation was seen at the dermal donor and recipient sites after 6 months as in the standard scar healing process. The dermis graft technique, besides potentially rendering a larger graft yield, reduced donor site morbidity, as it healed faster than the standard STSG. Due to its elastic properties, the DG procedure eliminated the meshing requirement (when compared to a 1:1.5 meshed STSG). This promising outcome presented for the DG technique needs to be further explored, especially regarding the elasticity of the dermal graft and its ability to reduce mesh patterns. Trial registration: ClinicalTrials.gov Identifier (NCT05189743) 12/01/2022. © 2022, The Author(s).

Blood group has been found to be important in the development of many diseases and the outcome of several disease processes, especially cardiovascular morbidity and mortality, such as caused by trauma and sepsis. The main reason is claimed to be related to glycobiology and effects mediated through the endothelium. This study investigated the possible effect of blood group (ABO) on burn care outcome. Burn outcome prediction models are extremely accurate and as such can be used to identify outcome effects even in single centre settings. In this retrospective risk adjusted observational study, we investigated the effect of ABO blood group on ventilatory time, length of hospital stay (LOS), and 90 day mortality among patients with burns. RESULTS: A total of 225 patients were included (2008-2019) with median TBSA of 26%; interquartile range (IQR) of 20-37%; median age 45 years (IQR 22-65 years); median Baux score (age + TBSA%); 76 (IQR 53- 97); 168 (75%) were male; median duration of hospital stay was 31 days (IQR 19-56); a total of 138 (61%) received treatment with mechanical ventilation; and 29 (13%) died. In a multivariable regression model, we were unable to isolate any significant effect of any blood group (O, A, B, AB) on the outcome measures studied (ventilatory time, LOS, and mortality). IN SUMMARY: contrary to many other major areas of disease in which ABO blood groups affect outcome, we were unable to find any such effect on patients with burns. Given the precision of the outcome models presented (AUC 0.93) any such an effect, if missed due to the limited study cohort, may be considered limited and to have only a minor clinical impact.

The clinical need for bone regenerative solutions is expanding with increasing life expectancy and escalating incidence of accidents. Several strategies are being investigated to enhance the osteogenic differentiation of stem cells. We previously reported two different approaches for this purpose, in monolayer and three-dimensional cell culture. The first approach was based on pretreating cells with 5-Aza-dC, a DNA methylation inhibitor, before the applying the differentiation media. The second approach was based on culturing cells on a glass surface during differentiation. In this study, we investigated the potential effect of combining both methods. Our results sug-gested that both approaches were associated with decreasing global DNA methylation levels. Cells cultured as a monolayer on glass surface showed enhancement in alkaline phosphatase activity at day 10, while 5-Aza-dC pretreatment enhanced the activity at day 5, irrespective of the culture surface. In three-dimensional pellet cul-ture, 5-Aza-dC pretreatment enhanced osteogenesis through Runx-2 and TGF-beta 1 upregulation while the glass surface induced Osterix.Furthermore, pellets cultured on glass showed upregulation of a group of miRNAs, including pro-osteogenesis miR-20a and miR-148b and anti-osteogenesis miR-125b, miR-31, miR-138, and miR-133a. Interestingly, 5-Aza-dC was not associated with a change of miRNAs in cells cultured on tissue culture plastic but reverted the upregulated miRNAs on the glass to the basal level. This study confirms the two approaches for enhancing osteogenic differentiation and contradicts their combination.

Risk adjustment and mortality prediction models are central in optimising care and for benchmarking purposes. In the burn setting, the Baux score and its derivatives have been the mainstay for predictions of mortality from burns. Other well-known measures to predict mortality stem from the ICU setting, where, for example, the Simplified Acute Physiology Score (SAPS 3) models have been found to be instrumental. Other attempts to further improve the prediction of outcome have been based on the following variables at admission: Sequential Organ Failure Assessment (_aSOFA) score, determinations of _aLactate or Neutrophil to Lymphocyte Ratio (_aNLR). The aim of the present study was to examine if estimated mortality rate (EMR, SAPS 3), _aSOFA, _aLactate, and _aNLR can, either alone or in conjunction with the others, improve the mortality prediction beyond that of the effects of age and percentage total body surface area (TBSA%) burned among patients with severe burns who need critical care. This is a retrospective, explorative, single centre, registry study based on prospectively gathered data. The study included 222 patients with median (25th-75th centiles) age of 55.0 (38.0 to 69.0) years, TBSA% burned was 24.5 (13.0 to 37.2) and crude mortality was 17%. As anticipated highest predicting power was obtained with age and TBSA% with an AUC at 0.906 (95% CI 0.857 to 0.955) as compared with EMR, _aSOFA, _aLactate and _aNLR. The largest effect was seen thereafter by adding _aLactate to the model, increasing AUC to 0.938 (0.898 to 0.979) (p < 0.001). Whereafter, adding EMR, _aSOFA, and _aNLR, separately or in combinations, only marginally improved the prediction power. This study shows that the prediction model with age and TBSA% may be improved by adding _aLactate, despite the fact that _aLactate levels were only moderately increased. Thereafter, adding EMR, _aSOFA or _aNLR only marginally affected the mortality prediction.

Autologous keratinocytes or stem cell based therapies are modern approaches for the treatment of skin loss in burn victims and chronic wound patients. The aim of this study is to identify depth-resolved structural changes in treated burn wounds using Spatial Frequency Domain Imaging (SFDI). When altering the investigated depth into tissue via the spatial frequency used in our calculations, we found changes in the scattering parameters for the treated samples. These scattering changes are correlated with histology, indicating a potential means to monitor re-epithelization and collagen formation during the treatment process across the entire wound area.