Facial Skin Rejuvenation Using Poly- dl -Lactic Acid Injected With a Laser-Generated Needle-Free Microjet Injector.

BACKGROUND: A laser-induced needle-free microjet injector was developed for rapid, high-speed drug delivery of microliters into the skin. OBJECTIVE: This study evaluated the clinical rejuvenation effect of repeated dermal injections of the collagen simulator poly- dl -lactic acid (PDLA) using a laser-induced needle-free microjet injector. METHODS: Five PDLA injection sessions using a laser-induced needle-free microjet injector were conducted in patients concerned about aging skin. Facial uplifting, darkness, redness, roughness, pore size, subjective satisfaction, and side effects were evaluated before each session and 4 weeks after treatment completion. Histological evaluation was also performed with immunohistochemical staining of collagen and elastic fibers. RESULTS: The clinical results of 27 female patients were evaluated. The treatment resulted in a noticeable skin surface uplifting (0.711 ± 0.42 mm) and significant improvements in darkness ( p = .013), redness ( p = .009), and roughness ( p = .036), with no significant difference in the pore size ( p = .770). Patients were reported being satisfied with the overall therapeutic effects, despite mild and tolerable adverse effects. Histological findings revealed growth and thickening of collagen and elastic fibers, with marked increase in collagen I and III levels. CONCLUSION: Repeated dermal injections of PDLA using a laser-induced microjet injector offer excellent drug delivery, achieving high efficacy in skin rejuvenation, patient satisfaction, and safety.

PLGA Nanoparticles Based Mucoadhesive Nasal In Situ Gel for Enhanced Brain Delivery of Topiramate.

Oral Topiramate therapy is associated with systemic adverse effects including paresthesia,abdominal pain, and fluctuations in plasma levels. The purpose of this research was to develop an intranasal in situ gel based system comprising Topiramate polymeric nanoparticles and evaluate its potential both in vitro and in vivo. Poly (lactic-co-glycolic acid) (PLGA)nanoparticles prepared by nanoprecipitation method were added into the in situ gelling system of Poloxamer 407 and HPMC K4M. Selected formulation (TG5) was evaluated for physicochemical properties, nasal permeation and in vivo pharmacokinetics in rats. PLGAnanoparticles (O1) exhibited low particle size (~ 144.4 nm), good polydispersity index (0.202), negative zeta potential (-12.7 mV), and adequate entrapment efficiency (64.7%). Developed in situ gel showed ideal pH (6.5), good gelling time (35 s), gelling temperature(37℃), suitable viscosity (1335 cP)and drug content of 96.2%. In vitro drug release conformedto Higuchi release kinetics, exhibiting a biphasic pattern of initial burst release and sustained release for 24 h. Oral administration of the drug to Sprague-Dawley rats (G3) showed higher plasma Cmax(504 ng/ml, p < 0.0001) when compared to nasal delivery of in situ gel (G4) or solution (G5). Additionally, AUC0-α of G3 (8786.82 ng/ml*h) was considerably higher than othergroups. Brain uptake data indicates a higher drug level with G4 (112.47 ng /ml) at 12 h when compared to G3. Histopathological examination of groups; G1 (intranasal saline), G2(intranasal placebo), G3, G4, and G5 did not show any lesions of pathological significance. Overall, the experimental results observed were promising and substantiated the potential of developed in situ gel for intranasal delivery.

Moderate l-lactate administration suppresses adipose tissue macrophage M1 polarization to alleviate obesity-associated insulin resistance.

As a crucial metabolic intermediate, l-lactate is involved in redox balance, energy balance, and acid-base balance in organisms. Moderate exercise training transiently elevates plasma l-lactate levels and ameliorates obesity-associated type 2 diabetes. However, whether moderate l-lactate administration improves obesity-associated insulin resistance remains unclear. In this study, we defined 800 mg/kg/day as the dose of moderate l-lactate administration. In mice fed with a high-fat diet (HFD), moderate l-lactate administration for 12 weeks was shown to alleviate weight gain, fat accumulation, and insulin resistance. Along with the phenotype alterations, white adipose tissue thermogenesis was also found to be elevated in HFD-fed mice. Meanwhile, moderate l-lactate administration suppressed the infiltration and proinflammatory M1 polarization of adipose tissue macrophages (ATMs) in HFD-fed mice. Furthermore, l-lactate treatment suppressed the lipopolysaccharide-induced M1 polarization of bone marrow-derived macrophages (BMDMs). l-lactate can bind to the surface receptor GPR132, which typically drives the downstream cAMP-PKA signaling. As a nutrient sensor, AMP-activated protein kinase (AMPK) critically controls macrophage inflammatory signaling and phenotype. Thus, utilizing inhibitors of the kinases PKA and AMPK as well as siRNA against GPR132, we demonstrated that GPR132-PKA-AMPKα1 signaling mediated the suppression caused by l-lactate treatment on BMDM M1 polarization. Finally, l-lactate addition remarkably resisted the impairment of lipopolysaccharide-treated BMDM conditional media on adipocyte insulin sensitivity. In summary, moderate l-lactate administration suppresses ATM proinflammatory M1 polarization through activation of the GPR132-PKA-AMPKα1 signaling pathway to improve insulin resistance in HFD-fed mice, suggesting a new therapeutic and interventional approach to obesity-associated type 2 diabetes.

Ultrastructural Evidence for a Role of Astrocytes and Glycogen-Derived Lactate in Learning-Dependent Synaptic Stabilization.

Long-term memory formation (LTM) is a process accompanied by energy-demanding structural changes at synapses and increased spine density. Concomitant increases in both spine volume and postsynaptic density (PSD) surface area have been suggested but never quantified in vivo by clear-cut experimental evidence. Using novel object recognition in mice as a learning task followed by 3D electron microscopy analysis, we demonstrate that LTM induced all aforementioned synaptic changes, together with an increase in the size of astrocytic glycogen granules, which are a source of lactate for neurons. The selective inhibition of glycogen metabolism in astrocytes impaired learning, affecting all the related synaptic changes. Intrahippocampal administration of l-lactate rescued the behavioral phenotype, along with spine density within 24 hours. Spine dynamics in hippocampal organotypic slices undergoing theta burst-induced long-term potentiation was similarly affected by inhibition of glycogen metabolism and rescued by l-lactate. These results suggest that learning primes astrocytic energy stores and signaling to sustain synaptic plasticity via l-lactate.

Randomized, Double-Blind, Placebo-Controlled Study of Poly-L-Lactic acid for Treatment of Cellulite in the Lower Extremities.

BACKGROUND: Poly-l-lactic acid (PLLA) is an injectable volumizer with biostimulatory properties used for volumetric structural rejuvenation in patients with facial fat volume loss but has increasingly been utilized for off-face applications. OBJECTIVE: The objectives of this randomized, double-blind, placebo-controlled single center study was to assess the safety and effectiveness of PLLA for the treatment of lower extremity cellulite in adult women. METHODS: 31 healthy women were enrolled in the study. Eligible subjects received 3 treatments every 4 weeks with either PLLA (treatment group) or saline (control group) injections combined with subcision, into each of the glutes or thighs. Follow-up visits were at 1, 3, and 6 months after treatment. Assessments included live ratings, rating of standardized pictures by a blinded evaluator, patient questionnaires, safety, and tolerability ratings. RESULTS: At the 3 and 6-month follow-up, there was a statistically significant change in the global aesthetic improvement scale (GAIS) compared to baseline as assessed by blinded investigators. Significant improvements were shown in the cellulite severity scale (CSS) as well as in the subject satisfaction questionnaires. Treatments were found to be tolerable, and no severe treatment-related adverse events occurred. CONCLUSION: Repeated PLLA treatments combined with subcision are effective and safe in improving the appearance of cellulite. J Drugs Dermatol. 20(5): doi:10.36849/JDD.5380.

Chart Review Presenting Safety of Injectable PLLA Used With Alternative Reconstitution Volume for Facial Treatments.

BACKGROUND: Since the approval of Sculptra Aesthetic, the amount of sterile water used to reconstitute the product has gradually increased in clinical practice. A retrospective chart review was conducted to evaluate patient safety associated with a larger reconstitution volume, and to investigate specific parameters for how Sculptra Aesthetic is used in a real-world clinical setting. OBJECTIVE: The primary objective of the study was to evaluate the safety of Sculptra Aesthetic when using a reconstitution volume of 7 to 10 mL, via collection of adverse events related to the product or injection procedure reported in medical records. METHODS: This was a multi-center, retrospective chart review conducted in the US. Medical records for subjects treated in the facial area with Sculptra Aesthetic reconstituted to 7–10 mL were reviewed to obtain information about demographics, treatment data, and adverse events. Each injector completed a questionnaire regarding reconstitution and injection procedures generally used. RESULTS: There were 4483 treatments performed in 1002 subjects; nearly half (48%) had 3 or 4 treatments during the studied period. Subjects most commonly received treatment in the midface/cheek area (97%), temple (94%), and jawline (54%). All injectors indicated adding lidocaine to the solution, resulting in total volumes of 8–10 mL. Adverse events were reported by 3.6% of subjects, all mild in intensity. Nodules were reported by 4 subjects (0.4%). CONCLUSION: The low number of AEs reported in this retrospective chart review suggests that facial aesthetic treatment with PLLA reconstituted to a final volume of 8–10 mL, including anesthetics, is associated with a favorable risk benefit ratio. J Drugs Dermatol. 2021;20(1):18-22. doi:10.36849/JDD.5631.

Vaginal treatment with lactic acid gel delays relapses in recurrent urinary tract infections: results from an open, multicentre observational study.

PURPOSE: The main objective of this open, prospective, multicentre, observational study is to investigate the relapse rate and tolerability of lactic acid gels in adult female patients with recurrent urinary tract infections during routine practice. METHODS: Data were collected from patients undergoing intermittent short courses of intravaginal treatment with lactic acid gel for prevention of recurrent urinary tract infections. The observation period for individual patients was 4 months, aimed at covering four short courses of intravaginal treatment. Data on UTI relapses, tolerability, handling and satisfaction with the treatment were collected via patient diaries and physician assessments and comprised any adverse events (AEs). RESULTS: In total, 72 patients were treated. During the last 12 months prior to the study, patients had on average 4.0 UTIs. In the 4 months after commencing treatment, 63.5% of patients had no recurrence of UTI symptoms. Overall efficacy was rated by physicians as 'excellent/good' for 96.7% of patients. The patients' overall acceptance of local treatment was high with 94.1% being '(very) satisfied'. Similarly, handling was rated as '(very) easy' by 94.2% of patients. The tolerability was assessed as 'highly tolerable/tolerable' by over 98% of patients and physicians alike. Safety analyses reported six AEs of mild intensity, all of which had resolved by the end of the study. CONCLUSION: Treatment with lactic acid gel may increase resilience against uropathogens, possibly preventing the need for antibiotic prevention of recurrent urinary tract infections. Treatment was positively assessed by the patients. The physician assessments corroborate these findings. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: DRKS00016760, 18.02.2019.

Lactic Acid Supplementation Increases Quantity and Quality of Gametocytes in Plasmodium falciparum Culture.

Malaria infection by Plasmodium falciparum continues to afflict millions of people worldwide, with transmission being dependent upon mosquito ingestion of the parasite gametocyte stage. These sexually committed stages develop from the asexual stages, yet the factors behind this transition are not completely understood. Here, we found that lactic acid increases gametocyte quantity and quality in P. falciparum culture. Low-passage-number NF54 parasites exposed to 8.2 mM lactic acid for various times were monitored using blood film gametocyte counts and RNA analysis throughout 2 weeks of gametocyte development in vitro for a total of 5 biological cohorts. We found that daily continuous medium exchange and 8.2 mM lactic acid supplementation increased gametocytemia approximately 2- to 6-fold relative to controls after 5 days. In membrane feeding mosquito infection experiments, we found that gametocytes continuously exposed to 8.2 mM lactic acid supplementations were more infectious to Anopheles stephensi mosquitoes, essentially doubling prevalence of infected midguts and oocyst density. Supplementation on days 9 to 16 did not increase the quantity of gametocytes but did increase quality, as measured by oocyst density, by 2.4-fold. Lactic acid did not impact asexual growth, as measured by blood film counts and luciferase quantification, as well as radioactive hypoxanthine incorporation assays. These data indicate a novel role for lactic acid in sexual development of the parasite.

Effects of sorbitol and lactate on erythropoietin production in HepG2 cells.

Promotion of erythropoietin (EPO) production is important for erythropoiesis as well as cell viability. The most effective inducing factor for EPO production is hypoxia. Hypoxia inducible factor (HIF), a regulator of EPO production, is increased under hypoxic conditions and is also affected by various regulators such as sirtuin1 (SIRT1). SIRT1 is regulated by the cytoplasmic redox state, which is thought to affect EPO production. Therefore, we investigated the effects of sorbitol and lactic acid, which serve as substrates for cellular respiration and bring cells into a reduced state, on EPO production in HepG2 cells. The addition of low-concentration sorbitol to HepG2 cells produced a mildly reduced state similar to that of hypoxia and increased NAD+, SIRT1, and HIF-α, and EPO mRNA expression. On the other hand, lactate suppressed EPO mRNA expression at all concentrations. Inhibition of lactate production from pyruvate abolished the effect of low sorbitol concentrations on EPO mRNA expression. When low-concentration sorbitol and a reducing agent were administered simultaneously, the effect of increasing EPO mRNA expression disappeared. It was suggested that SIRT1 and EPO production increased under conditions where lactate production was not suppressed, even under mildly reduced conditions similar to hypoxia.

Dietary Phytase- and Lactic Acid-Treated Cereals Caused Greater Taxonomic Adaptations than Functional Adaptations in the Cecal Metagenome of Growing Pigs.

Phosphorus (P) is an essential nutrient for the gut bacteria and the host. Nevertheless, little information exists that indicates to what extent an improved level of P availability in the small intestine leads to functional adaptations in bacterial metabolic pathways in the large intestine. Therefore, we investigated the changes in the taxonomic and functional bacterial metagenome in cecal digesta of growing pigs fed diets containing phytase and/or cereals treated with 2.5% lactic acid (LA) for 19 days (n = 8/diet) using shotgun metagenome sequencing. The phytase supplementation resulted in strikingly distinct bacterial communities, affecting almost all major bacterial families, whereas functional changes were less dramatic among the feeding groups. While phytase treatment decreased predominant Prevotellaceae levels, it seemed that Clostridiaceae, Ruminococcaceae, and Lachnospiraceae filled the opening metabolic niches (P < 0.05). The LA-treated cereals mediated reduced levels of Bacteroidaceae and increased levels of Veillonellaceae, but those results were mainly seen when the cereals were fed as a single treatment (P < 0.05). In association with the taxonomic alterations, phytase caused changes within the major functional pathways corresponding to amino acid metabolism; translation; membrane transport; folding, sorting, and degradation; and energy metabolism, whereas the LA treatment of cereals resulted in decreased enzymatic capacities within the carbohydrate metabolism and energy metabolism pathways (P < 0.05). Metabolic dependencies corresponding to the starch and sucrose metabolism, glycolysis/gluconeogenesis, and citrate cycle pathways were indicated by diet-associated changes in enzymatic capacities related to short-chain fatty acid, methane, vitamin, and bacterial antigen synthesis. Accordingly, the present results support the idea of the importance of the availability of intestinal P for bacterial metabolism. However, the functional profiles were less different than the taxonomic profiles among the dietary treatment results, indicating a certain degree of metabolic plasticity within the cecal metagenome.IMPORTANCE Dietary strategies (e.g., phytase supplementation and lactic acid [LA] treatment of cereals) used to improve the availability of phytate-phosphorus (P) from pig feed reduce the amount of P flowing into the large intestine, whereas LA treatment-induced changes in nutrient fractions alter the substrate being available to the microbiota. In ruminants, lower intestinal P availability compromises the fibrolytic activity of the microbiome. Here, we report that the functional capacities were less dramatically affected than the taxonomic composition by phytase-supplemented and LA-treated cereals. The bacterial community appeared to be partly capable of functionally compensating for the altered flow of P by replacing taxa with higher P needs by those with lower P needs. Therefore, by acting as mucosal immune stimulants, alterations in microbiota-associated molecular patterns (MAMPs) due to the taxonomic shifts may play a greater role for host physiology and health than functional differences caused by differing intestinal P availabilities, which merits further research.

Alterations of the Viable Ileal Microbiota of the Gut Mucosa-Lymph Node Axis in Pigs Fed Phytase and Lactic Acid-Treated Cereals.

The gut-lymph node axis is a critical player in the symbiotic relationship between gut microbiota and the host. However, little is known about the impact of diet-related bacterial shifts in the gut lumen on bacterial translocation into lymph nodes. Here, we (i) characterized changes in the viable microbiota composition along the ileal digesta-mucosa-lymph node axis and (ii) examined the effect of dietary phytase supplementation and lactic acid (LA) soaking of cereals on the bacterial taxonomy along this axis, together with their effect on the mucosal expression of innate immune and barrier function genes in pigs (n = 8/diet). After 18 days on diets, ileal digesta, mucosa, and ileocecal lymph nodes (ICLNs) were collected for RNA isolation and 16S rRNA-based high-resolution community profiling. Bacterial communities were dominated by Lactobacillaceae and Clostridiaceae, with clearly distinguishable profiles at the three sampling sites. Specific bacterial subsampling was indicated by enrichment of the ICLNs with Lactobacillaceae, Lachnospiraceae, Veillonellaceae, and Methanobacteriaceae and less Clostridiaceae, Pasteurellaceae, Helicobacteraceae, and Enterobacteriaceae compared to that of the mucosa. LA treatment of cereals reduced proteolytic taxa in the lumen, including pathobionts like Helicobacteraceae, Campylobacteraceae, and Fusobacteriaceae When combined, phytase- and LA-treated cereals largely increased species richness, while the single treatments reduced Actinobacteria and Bacteroidetes in ICLNs and increased mucosal MUC2 expression. In contrast, phytase reduced mucosal CDH1 expression, indicating altered barrier function with potential effects on bacterial translocation. Overall, both treatments, although often differently, changed the viable microbiome along the digesta-mucosa-lymph node axis in the ileum, probably due to altered substrate availability and microbial-host interactions.IMPORTANCE A host's diet largely determines the gut microbial composition and therefore may influence bacterial translocation into ICLNs. Due to its importance for cell metabolism, the intestinal phosphorus availability, which was modified here by phytase and LA treatment of cereals, affects the intestinal microbiota. Previous studies mainly focused on bacteria in the lumen. The novelty of this work resides mainly in that we report diet-microbe effects along the digesta-mucosa-ICLN axis and linked those effects to mucosal expression of barrier function genes as crucial components for host health. Lymph nodes can serve as reservoir of pathobionts; therefore, present diet-microbiome-host interactions have implications for food safety.

Thermodynamic, Spatial and Methodological Considerations for the Manufacturing of Therapeutic Polymer Nanoparticles.

PURPOSE: Evaluate fundamental parameters that dictate the effectiveness of drug loading. METHODS: A model water-soluble drug lacking ionizable groups, pirfenidone (PFD), was encapsulated through nanoprecipitation in poly(ethylene glycol)-poly(lactic acid) (PEG-PLA)-poly(lactic-co-glycolic acid) (PLGA) NPs. Firstly, the thermodynamic parameters predicting drug-polymer miscibility were determined to assess the system's suitability. Then, the encapsulation was evaluated experimentally by two different techniques, bulk and microfluidic (MF) nanoprecipitation. Additionally, the number of molecules that fit in a particle core were calculated and the loading determined experimentally for different core sizes. Lastly, the effect of co-encapsulation of α-lipoic acid (LA), a drug with complementary therapeutic effects and enhanced lipophilicity, was evaluated. RESULTS: The thermodynamic miscibility parameters predicted a good suitability of the selected system. MF manufacturing enhanced the encapsulation efficiency by 60-90% and achieved a 2-fold higher NP cellular uptake. Considering spatial constrictions for drug encapsulation and increasing the size of the PLGA core the number of PFD molecules per NP was raised from under 500 to up to 2000. More so, the co-encapsulation of LA increased the number of drug molecules per particle by 96%, with no interference with the release profile. CONCLUSIONS: Thermodynamic, spatial and methodological parameters should be considered to optimize drug encapsulation.

Lactate kinetics in ICU patients using a bolus of 13C-labeled lactate.

BACKGROUND: Plasma lactate concentrations and their trends over time are used for clinical prognosis, and to guide treatment, in critically ill patients. Although heavily relied upon for clinical decision-making, lactate kinetics of these patients is sparsely studied. AIM: To establish and validate a feasible method to study lactate kinetics in critically ill patients. METHODS: Healthy volunteers (n = 6) received a bolus dose of 13C-labeled lactate (20 µmol/kg body weight), and 43 blood samples were drawn over 2 h to determine the decay in labeled lactate. Data was analyzed using non-compartmental modeling calculating rates of appearance (Ra) and clearance of lactate. The area under the curve (AUC) was calculated using a linear-up log-down trapezoidal approach with extrapolation beyond 120 min using the terminal slope to obtain the whole AUC. After evaluation, the same protocol was used in an unselected group of critically ill patients (n = 10). RESULTS: Ra for healthy volunteers and ICU patients were 12.8 ± 3.9 vs 22.7 ± 11.1 µmol/kg/min and metabolic clearance 1.56 ± 0.39 vs 1.12 ± 0.43 L/min, respectively. ICU patients with normal lactate concentrations showed kinetics very similar to healthy volunteers. Simulations showed that reducing the number of samples from 43 to 14 gave the same results. Our protocol yielded results on lactate kinetics very similar to previously published data using other techniques. CONCLUSION: This simple and user-friendly protocol using an isotopically labeled bolus dose of lactate was accurate and feasible for studying lactate kinetics in critically ill ICU patients. TRIAL REGISTRATION: ANZCTR, ACTRN12617000626369, registered 8 March 2017. https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372507&isReview=true.

Cutaneous vessel features of sensitive skin and its underlying functions.

BACKGROUND: Following the sufficient studies of the effects of skin barrier impairment and heightened neural reaction on sensitive skin (SS), many scholars have paid great attention to the roles of superficial microvasculature in SS. METHODS: By questionnaire survey, lactic acid sting test, and capsaicin test, eligible subjects were classified as normal skin, only lactic acid sting test positive (LASTP), only capsaicin test positive (CATP), and both positive (both LASTP and CATP). D-OCT was used to photograph images for evaluating the cutaneous vessels features each group. RESULTS: Totally 137 subjects completed the study. Compared with LASTN group, the vascular vessels were closer to epidermis in LASTP group. Mesh and branching vessels were more popular in SS than normal skin. High blood vessel density was more prevalent in SS, while low density frequently presented in normal skin. The vascular depth had a closely negative correlation with face flushing and SSS, and vascular shapes had a good positive correlation with face flushing and SSB. CONCLUSIONS: Our study indicates that there is a significant difference in vascular depth, shape, and density between SS and normal skin which is valuable to explore SS pathologic mechanism and to further investigate cutaneous microvasculature functions in SS.

Objective Evaluation of Skin Sensitivity Across Fitzpatrick Skin Types.

Context: Skin sensitivity may be best defined as self-reported intolerance to application of skincare products. It is commonly believed that individuals with darker skin are generally less sensitive, while those lighter skin are more sensitive. However, there is little objective data correlating sensitivity with skin type or with objective measures of sensitivity. Objective: This study assessed Fitzpatrick skin type and self-reported perception of skin sensitivity. Design: A single-blinded, lactic acid sting test was performed on the medial cheeks, where patients were randomized to receive room temperature 10% lactic acid on the left or right cheek with water applied to the contralateral cheek as a control. Outcome Measures: Stinging was assessed 1 minute after application of test solution to one cheek using a visual analogue scale (VAS). Results: There was a statistically significant difference in self-reported skin sensitivity in patients with Fitzpatrick skin types 1-3 vs 4-6 (73.6% vs 46.5%; P= 0.006). Patients who had higher perceived sensitivity were more likely to have objectively measured sensitivity as well, across all skin types (P<0.01). When stratified by skin type, a numerically higher percentage of subjects with Fitzpatrick skin types 1-3 experienced objective sensitivity compared to subjects with skin types 4-6 (45.6% vs 27.9; P=0.058). Conclusions: Patients with self-perceived skin sensitivity were more likely to develop objective stinging compared to those who did not report sensitivity. Skin sensitivity can occur across all skin types, and patients should be asked about self-perceptions of sensitivity as it is likely an indicator of true sensitivity. J Drugs Dermatol. 2020;19(7): doi:10.36849/JDD.2020.5880.

Immediate Use After Reconstitution of a Biostimulatory Poly-L-Lactic Acid Injectable Implant.

BACKGROUND: Poly-L-lactic acid (PLLA) is a biodegradable, synthetic polymer that stimulates collagen production and can improve skin quality, volume, and thickness. The current reconstitution procedure for Sculptra, a PLLA-containing injectable device involves 2 hours standing time before use. OBJECTIVE: To evaluate and validate an immediate-use procedure for reconstituting a PLLA-containing injectable device. METHODS AND MATERIALS: Three batches of the product were shaken for 1 minute immediately after reconstitution with 8 mL of sterile water. Different physicochemical tests including viscosity, concentration of excipients (sodium carboxymethylcellulose and mannitol), pH, and particle size distribution were performed for standing times 0, 2, 24, and 72 hours after immediate shaking, and compared with the standard 2 hours standing time before shaking. The recovery and stability of optional addition of 1 mL of 2% lidocaine hydrochloride was also assessed. RESULTS: All physiochemical parameters evaluated were equivalent, regardless of reconstitution procedure, showing that shaking vigorously for 1 minute dissolves the excipients of the product properly without a required standing time and with no impact to the PLLA particles. There were no differences in lidocaine hydrochloride content of suspensions after 0 and 72 hours. CONCLUSION: The PLLA-containing product can be used immediately after reconstitution including vigorous shaking, as shown from physicochemical analyses. Optional addition of lidocaine hydrochloride is feasible. J Drugs Dermatol. 2020;19(12): doi:10.36849/JDD.2020.5228.

Crystallization behavior and crystal properties of lactose as affected by lactic, citric, or phosphoric acid.

The presence of acids in a lactose-containing system can affect its crystallization. The crystallization kinetics of lactose solutions were investigated as affected by lactic, citric, or phosphoric acid at a concentration of 0.05, 1, or 4% (wt/wt) as compared with that of pure lactose. The crystallization behavior of lactose was affected differently by the presence of all 3 acids and was mostly concentration dependent. The presence of 1 and 4% citric or phosphoric acid reduced the crystal yield significantly (≥18%) as compared with that of pure lactose (∼82%). Thermographic analysis of lactose crystals showed that the presence of 1% lactic, 0.05 and 1% citric, and 4% phosphoric acids in the lactose solutions induced the formation of amorphous lactose. X-Ray diffraction analysis revealed that the lactose crystallized mainly into α-lactose monohydrate, stable anhydrous α-lactose, and anhydrous crystals containing α-lactose and ß-lactose in a molar ratio of 5:3 and 4:1. Average size of the lactose particles, comprising of several crystallites, declined depending on the type of the acids and their concentration, but size of a single crystallite was not altered. The findings suggested that the lactose crystallization and crystal properties are governed by the lactose-water interactions, which can be influenced by the presence of acids in a concentration-dependent manner.

Astrocyte-neuron lactate shuttle sensitizes nociceptive transmission in the spinal cord.

Astrocytes play a key role in the maintenance of synaptic transmission by producing L-lactate via the astrocyte-neuron lactate shuttle (ANLS). Astrocyte activation in the spinal cord is involved in the expression of neuropathic pain. We investigated the role of the ANLS in the spinal cord on hyperalgesia in neuropathic pain in mice. Specific activation of dorsal horn astrocytes induced mechanical hyperalgesia, which was attenuated by α-cyano-4-hydroxycinnamate (4-CIN), an inhibitor of monocarboxylate transporters that deliver L-lactate from astrocytes to neurons. Intrathecal L-lactate administration lowered the mechanical nociceptive threshold, which was attenuated by pretreatment with 4-CIN and isosafrole (a lactate dehydrogenase inhibitor), but not gliotoxin. Intrathecal L-lactate administration significantly upregulated c-Fos and cofilin phosphorylation, which was reversed by 4-CIN. The lowered mechanical nociceptive threshold was significantly attenuated by intrathecal fluorocitrate (an astrocyte-specific Krebs cycle inhibitor), 4-CIN, and isosafrole treatment. Thus, these results suggested that, in neuropathic pain, mechanical hyperalgesia was maintained by excessive L-lactate supplied by activated astrocytes via an aberrant ANLS.

Effects of lactate ions on the cardiorespiratory system in rainbow trout (Oncorhynchus mykiss).

Lactate ions are involved in several physiological processes, including a direct stimulation of the carotid body, causing increased ventilation in mammals. A similar mechanism eliciting ventilatory stimulation in other vertebrate classes has been demonstrated, but it remains to be thoroughly investigated. Here, we investigated the effects of lactate ions on the cardiorespiratory system in swimming rainbow trout by manipulating the blood lactate concentration. Lactate elicited a vigorous, dose-dependent elevation of ventilation and bradycardia at physiologically relevant concentrations at constant pH. After this initial confirmation, we examined the chiral specificity of the response and found that only l-lactate induced these effects. By removal of the afferent inputs from the first gill arch, the response was greatly attenuated, and a comparison of the responses to injections up- and downstream of the gills collectively demonstrated that the lactate response was initiated by branchial cells. Injection of specific receptor antagonists revealed that a blockade of serotonergic receptors, which are involved in the hypoxic ventilatory response, significantly reduced the lactate response. Finally, we identified two putative lactate receptors based on sequence homology and found that both were expressed at substantially higher levels in the gills. We propose that lactate ions modulate ventilation by stimulating branchial oxygen-sensing cells, thus eliciting a cardiorespiratory response through receptors likely to have originated early in vertebrate evolution.

Effects of an over-the-counter lactic-acid containing intra-vaginal douching product on the vaginal microbiota.

BACKGROUND: Over-the-counter intra-vaginal lactic-acid containing douches are marketed as vaginal hygiene products that support optimal vaginal pH balance. We report the effect of a commercially available douche (Etos®) on the vaginal microbiota (VM) in a prospective study. RESULTS: Twenty-five healthy women were recruited through advertisements in 2015-2017 (ethical approval: METC-2014_413) and followed over three menstrual cycles. The participants had a median age of 24 years [IQR: 22-29], were mostly Dutch-Caucasian (88%), and 60% used combined oral contraceptives. All participants douched three times a week during the second cycle, starting on the first day of that cycle. Participants completed a questionnaire at baseline, kept a daily diary to report douching, menses, and sexual activity, self-collected vaginal swabs every other day during the first and third cycle and daily during the second cycle, and measured vaginal pH mid-cycle. A median of 44 vaginal swabs [inter-quartile range (IQR): 41-50] were assessed per participant by 16S rRNA gene (V3-V4 region) sequencing and a Candida albicans PCR was done at four time-points. At baseline, 21 participants (84%) had Lactobacillus-dominated VM (Lactobacillus crispatus (n = 14), L. iners (n = 6), or diverse Lactobacillus species (n = 1) and 4 participants (16%) had VM consisting of diverse anaerobes. In multinomial logistic regression models, a trend towards increased odds were observed for having diverse anaerobic VM in the second and third cycle, compared to the first cycle, after adjusting for menses [odds ratio (OR) = 1.4 (95% CI: 0.9-2.1) and OR = 1.7 (95% CI: 0.9-3.1), respectively] (p = 0.376). Douching did not affect vaginal pH. Menses increased the odds for having VM consisting of diverse anaerobes almost two-fold (OR = 1.7; 95% CI: 1.0-2.8), while douching during menses increased the odds 2.6 fold (OR = 2.6; 95% CI: 1.0-6.5), compared to not menstruating (p = 0.099). Participants were more likely to test positive for C. albicans after cycle 2, compared to cycle 1 [OR = 3.0 (95% CI: 1.2-7.2); p = 0.017]. CONCLUSION: The Etos® douche did not significantly affect the vaginal pH or VM composition, although increased odds for having diverse anaerobic VM was observed, especially when douching during menses. Furthermore, douching may promote C. albicans infections.