Keratosis Pilaris Treatment Paradigms: Assessing Effectiveness Across Modalities.

This review aims to present a comprehensive synthesis of the existing treatment modalities for keratosis pilaris (KP) and evaluate their therapeutic efficacy. Keratosis pilaris (KP) is a prevalent chronic dermatological condition typified by its unique 'chicken skin appearance', with the cheeks being the most commonly involved sites. Numerous therapeutic interventions have emerged, given its substantial prevalence and impact on skin aesthetics and psychological well-being. Nonetheless, a consistent therapeutic response has been challenging to achieve. This review endeavors to collate and critically appraise the current treatment landscape for KP. An exhaustive literature search was performed using databases such as Ovid, PubMed and Scopus. From an initial count of 459 articles identified post-deduplication, 52 were selected for inclusion after a thorough full-text examination for articles with concrete outcome data highlighting the efficacies of different therapeutic modalities while excluding articles that lacked data or were tangential to the core focus on KP treatment. These articles were then cataloged based on the nature of treatment strategies and their respective outcomes. Among the various therapeutic interventions, laser and light modalities appear to be supported by the most substantial evidence base. Notably, the Nd: YAG laser, attributed to its longer wavelength, emerges as a preferred option. While other therapeutic avenues have also exhibited notable improvements in skin texture and discoloration relative to baseline, the inconsistency in outcome measures underscores the imperative need for a standardized, KP-specific scoring system to foster a more coherent comparison across treatments. Based on the current evidence, Nd: YAG laser therapy demonstrates promising effectiveness with a relatively favorable side effect profile. However, the landscape of KP treatment is multifaceted, and further studies are essential to solidify recommendations.

A Review of the Scoring and Assessment of Keratosis Pilaris.

Disease severity assessment tools play a large part in evaluating skin conditions in dermatology. Currently, there is no existing validated assessment tool for keratosis pilaris (KP), a benign yet highly prevalent follicular disorder. A range of proposed scoring tools have been used in different clinical trials for the assessment of potential treatments for KP. A literature review of the current scoring systems used for KP shows that there is a lack of consistency with most studies using varying versions of unvalidated investigator global assessment (IGA) scores and quartile grading systems. A review of these studies shows that current methods of evaluating KP in clinical trials are subjective, unreliable, and inconsistent. A standardised and validated scoring system would be significant as it could be used in clinical trials to advance the current knowledge of KP.

Mechanosensitive stem cell fate choice is instructed by dynamic fluctuations in activation of Rho GTPases.

During the intricate process by which cells give rise to tissues, embryonic and adult stem cells are exposed to diverse mechanical signals from the extracellular matrix (ECM) that influence their fate. Cells can sense these cues in part through dynamic generation of protrusions, modulated and controlled by cyclic activation of Rho GTPases. However, it remains unclear how extracellular mechanical signals regulate Rho GTPase activation dynamics and how such rapid, transient activation dynamics are integrated to yield long-term, irreversible cell fate decisions. Here, we report that ECM stiffness cues alter not only the magnitude but also the temporal frequency of RhoA and Cdc42 activation in adult neural stem cells (NSCs). Using optogenetics to control the frequency of RhoA and Cdc42 activation, we further demonstrate that these dynamics are functionally significant, where high- vs. low-frequency activation of RhoA and Cdc42 drives astrocytic vs. neuronal differentiation, respectively. In addition, high-frequency Rho GTPase activation induces sustained phosphorylation of the TGFß pathway effector SMAD1, which in turn drives the astrocytic differentiation. By contrast, under low-frequency Rho GTPase stimulation, cells fail to accumulate SMAD1 phosphorylation and instead undergo neurogenesis. Our findings reveal the temporal patterning of Rho GTPase signaling and the resulting accumulation of an SMAD1 signal as a critical mechanism through which ECM stiffness cues regulate NSC fate.

Gastric acid and escape to systemic circulation represent major bottlenecks to host infection by Citrobacter rodentium.

The gastrointestinal (GI) environment plays a critical role in shaping enteric infections. Host environmental factors create bottlenecks, restrictive events that reduce the genetic diversity of invading bacterial populations. However, the identity and impact of bottleneck events on bacterial infection are largely unknown. We used Citrobacter rodentium infection of mice, a model of human pathogenic Escherichia coli infections, to examine bacterial population dynamics and quantify bottlenecks to host colonization. Using Sequence Tag-based Analysis of Microbial Populations (STAMP) we characterized the founding population size (Nb') and relatedness of C. rodentium populations at relevant tissue sites during early- and peak-infection. We demonstrate that the GI environment severely restricts the colonizing population, with an average Nb' of only 12-43 lineages (of 2,000+ inoculated) identified regardless of time or biogeographic location. Passage through gastric acid and escape to the systemic circulation were identified as major bottlenecks during C. rodentium colonization. Manipulating such events by increasing gastric pH dramatically increased intestinal Nb'. Importantly, removal of the stomach acid barrier had downstream consequences on host systemic colonization, morbidity, and mortality. These findings highlight the capability of the host GI environment to limit early pathogen colonization, controlling the population of initial founders with consequences for downstream infection outcomes.