Glycerol fermentation by skin bacteria generates lactic acid and upregulates the expression levels of genes associated with the skin barrier function.

Commensal bacteria play a major role in multiple skin functions by providing the first layer of defense against pathogens and maintaining the skin barrier. Staphylococcus epidermidis is one of the most common skin commensals. In this study, we showed that S. epidermidis ferments glycerol and uses it as a nutrient, while producing short-chain and organic fatty acids, with the most notable being lactic acid. Lactic acid is an alpha-hydroxy acid that inhibits the growth of pathogenic bacteria, without any negative effect on the commensal bacteria itself. Using in vivo experiments, we validated our in vitro results, showing that the skin microbiome is also capable of doing this. Finally, using 2D and 3D skin culture models, we showed that the fermentation of glycerol, mainly lactic acid, as determined by analytical methods, upregulates the expression levels of several key genes that are associated with the barrier properties of the skin. While the hydration effect of glycerol on the skin is well known, our study shows the overall benefits of glycerol on the skin microbiome, while revealing an alternate mode of action of glycerol for multiple skin benefits.

Consumer Safety Considerations of Skin and Oral Microbiome Perturbation.

Microbiomes associated with human skin and the oral cavity are uniquely exposed to personal care regimes. Changes in the composition and activities of the microbial communities in these environments can be utilized to promote consumer health benefits, for example, by reducing the numbers, composition, or activities of microbes implicated in conditions such as acne, axillary odor, dandruff, and oral diseases. It is, however, important to ensure that innovative approaches for microbiome manipulation do not unsafely disrupt the microbiome or compromise health, and where major changes in the composition or activities of the microbiome may occur, these require evaluation to ensure that critical biological functions are unaffected. This article is based on a 2-day workshop held at SEAC Unilever, Sharnbrook, United Kingdom, involving 31 specialists in microbial risk assessment, skin and oral microbiome research, microbial ecology, bioinformatics, mathematical modeling, and immunology. The first day focused on understanding the potential implications of skin and oral microbiome perturbation, while approaches to characterize those perturbations were discussed during the second day. This article discusses the factors that the panel recommends be considered for personal care products that target the microbiomes of the skin and the oral cavity.

A rat H1t-GFP transgene recapitulates endogenous H1t expression pattern in mouse.

H1 histones bind to linker DNA. H1t (H1f6), a testis-specific linker histone variant, is present in pachytene spermatocytes and spermatids. The expression of H1t histone coincides with the acquisition of metaphase I competence in pachytene spermatocytes. Here we report the generation of H1t-GFP transgenic mice. The H1t-GFP (H1 histone testis-green fluorescence protein) fusion protein expression recapitulates the endogenous H1t expression pattern. This protein appears first in mid pachytene spermatocytes in stage V seminiferous tubules, persists in round spermatids and elongating spermatids, but is absent in elongated spermatids. The strong green fluorescence signal, due to the high abundance of H1t-GFP, is maintained in spermatocytes after induction towards metaphase I through treatment with okadaic acid. Therefore, H1t-GFP can be used as a visual marker for monitoring the progression of meiosis in vitro and in vivo, as well as fluorescence-activated cell sorting (FACS) sorting of germ cells.

Bioengineering and serum free expansion of blood-derived γδ T cells.

BACKGROUND AIMS: Cellular immunotherapy relies on several highly variable patient-specific parameters, such as (i) cell number before and after expansion, (ii) targeting of cells to tumors, (iii) cell survival and function after infusion, and (iv) on- and off-target adverse events. Cellular approaches such as the specific expansion of γδ T cells as opposed to αß T cells are being pursued. γδ T cells are reasonable candidates for immunotherapy because they (i) possess intrinsic anti-tumorigenicity, (ii) require no priming, (iii) direct tumor killing via recognition of stress-responsive ligands, and (iv), as we now show, can be expanded to clinical cell doses in current Good Manufacturing Practice serum-free media (SFM). METHODS: γδ T-cell expansion was evaluated in several SFMs. Additionally, the expanded γδ T cells were evaluated for their transduction efficiency using lentiviral vectors (LV). RESULTS: Of the SFM cultures, robust expansion was only observed in OpTmizer supplemented with high-dose interleukin-2. γδ T-cell percentages and numbers were sufficient for clinical use. Using cells from several donors, transduction efficiencies ranged from 13 to 33%, which is similar to transduction levels observed using αß T cells with similar multiplicity of infection. DISCUSSION: An optimized method of γδT-cell expansion and transduction was developed that can be tested in early-phase clinical trials. With appropriate elimination of the αßT cell-component, the absence of MHC-restriction affords the opportunity for use in the allogeneic setting with limited risk of graft versus host disease. Finally, the use of SFM provides clinically safer, widely applicable and potentially more efficacious cellular immunotherapy.

A cross-sectional study to assess any possible linkage of C/T polymorphism in CYP17A1 gene with insulin resistance in non-obese women with polycystic ovarian syndrome.

BACKGROUND & OBJECTIVES: Insulin resistance (IR) is a major confounding factor in polycystic ovarian syndrome (PCOS) irrespective of obesity. Its exact mechanism remains elusive till now. C/T polymorphism in the -34 promoter region of the CYP17 gene is inconsistently attributed to elucidate the mechanism of IR and its link to hyperandrogenemia in obese PCOS patients. In the present study we aimed to evaluate any association of this polymorphism with IR in non-obese women with PCOS. METHODS: Polymorphism study was performed by restriction fragment length polymorphism (RFLP) analysis of the Msp A1 digest of the PCR product of the target gene in 75 PCOS cases against 73 age and BMI matched control women. Serum testosterone, BMI and HOMA-IR (homeostatic model of assessment-insulin resistance) were analyzed by standard techniques. A realistic cut-off value for the HOMA-IR was obtained through receiver operating characteristic (ROC) curve for exploring any possible link between IR and T/C polymorphism in the case group. RESULTS: Significant increases in serum testosterone and HOMA-IR values were observed among the case group (P<0.001) without any significant elevation in BMI and FBG compared to controls. Cut-off value for IR in the PCOS patients was 1.40 against a maximum sensitivity of 0.83 and a minimum false positivity of 0.13. The analysis revealed an inconclusive link between the C/T polymorphic distribution and insulin resistant case subjects. INTERPRETATION & CONCLUSIONS: The results showed that CYP17A1 gene was not conclusively linked to either IR or its associated increased androgen secretion in non-obese women with PCOS. We propose that an increased sensitivity of insulin on the ovarian cells may be the predominant reason for the clinical effects and symptoms of androgen excess observed in non-obese PCOS patients in our region.

Protective Role of Bilirubin Against Increase in hsCRP in Different Stages of Hypothyroidism.

In conjunction with thyroxine, bilirubin may play an important role for regulation of hsCRP level and a consequent pro-inflammatory condition in hypothyroidism. In present study we evaluated the dependence of hsCRP changes on total bilirubin (BT) and fT4 level in thirty overt (OH) and thirty subclinical hypothyroidism (SH). Serum BT, hsCRP, thyroxine and TSH were measured in both groups and compared with forty control subjects. Serum values of TSH, hsCRP showed raised (P < 0.001 for both) values with lower levels for fT4 and BT (P < 0.001 and 0.03 respectively) in hypothyroid patients compared to the controls. ANOVA showed significant increments in TSH and hsCRP values with decreases in fT4 among the control, SH and OH groups respectively (P < 0.001). BT values showed decrease in OH group only in comparison to controls (P = 0.04). Regression analysis revealed that hsCRP was negatively dependent on fT4 (ß = -0.35, P = 0.002) and serum bilirubin (ß = -0.40 and P < 0.001 respectively). Univariate general linear model analysis showed this dependence persisted even when carried out distinctly in SH and OH groups separately (P < 0.001). TSH did not show any significant predictive value on the hsCRP level in either of these two tests. From these analyses we suggest that serum hsCRP is closely integrated to a lowered synthesis of bilirubin and fT4 in hypothyroid patients. Furthermore, this causal relationship is not only limited to overt but also extends to the SH.

Effect of Copper on l-Cysteine/l-Cystine Influx in Normal Human Erythrocytes and Erythrocytes of Wilson's Disease.

Wilson's disease is a disease of abnormal copper metabolism in which free serum copper level is raised. The objective of the study was to determine, whether in Wilson disease, l-cysteine/l-cystine influx into RBC was decreased or not and the specific amino acid transporter affected by copper in normal human RBC. For l-cysteine/l-cystine influx, ten untreated cases, ten treated cases and ten age and sex matched healthy controls were recruited. To study the effect of copper on l-cysteine/l-cystine influx in RBC, 15 healthy subjects were selected. RBC GSH and l-cysteine/l-cystine influx were estimated by Beautler's and Yildiz's method respectively. In untreated cases, l-cysteine/l-cystine influx and erythrocyte GSH level were decreased showing that elevated level of free copper in serum or media decreased l-cysteine/l-cystine influx in human RBC. Copper treatment inhibited L amino acid transporter in normal RBC specifically.

A study of the expression and localization of toll-like receptors 2 and 9 in different grades of cervical intraepithelial neoplasia and squamous cell carcinoma.

TLRs are important molecules of innate immune response, those play central role in host pathogen interaction and recognition through pathogen associated molecular patterns (PAMPs). Previous studies have indicated the role of TLRs in many human malignancy and cervical cancer in terms of viral recognition and inflammatory changes in-vivo. The objective of this study was to evaluate the expression and localization of toll-like receptor (TLR) 2 and TLR9 in preinvasive and invasive cervical cancer patients and to investigate its use as a probable diagnostic tool for better management cervical cancer. This single institution study includes individuals with normal, precancerous lesions, cervical intraepithelial neoplastic (CIN) and invasive squamous cell carcinoma (SCC) of the cervix. Upon confirmation by histopathology, fluorescence based immunohistochemistry was performed in all patients for TLR2 and TLR9, followed by semi-quantitative estimation of the staining intensity and grade of expression. The expression pattern of TLR2 and TLR9 does not vary greatly from normal to precancerous lesions, but a significant variation was observed in advance stages, i.e. squamous cell carcinoma of the uterine cervix. Additionally the expression increased marginally in higher grades. In spite of their low difference in expression along different stages of cervical cancer, both TLR2 and TLR9 could detect the disease at an advance stages as depicted by the receiver operator characteristics curve analysis.

Clinico-biochemical correlation between psoriasis and insulin resistance.

Psoriasis is a chronic inflammatory disease associated with an increased insulin resistance, obesity and cardiovascular risk. The present study was aimed to assess insulin resistance and pattern of body fat deposition in psoriasis. Body mass index (BMI) and waist circumference (WC) were measured in 40 psoriatic patients and 46 age- and sex-matched control subjects. Fasting blood glucose (FBG) and serum insulin level were measured by standard photometric method and ELISA respectively. HOMA-IR (homeostatic model of insulin resistance) was calculated by appropriate software. The results indicated that case and control groups were comparable in terms of age and sex (p = 0.934) with an increased prevalence of psoriasis among male subjects (60 %). FBG and mean WC between the two groups were statistically not significant (p value = 0.271 and 0.21 respectively). BMI was significantly higher in case group compared to the control group (p = 0.049). Serum insulin level and insulin resistance in the psoriatic patients were significantly higher (p value <0.001). Multiple regression analysis revealed that insulin resistance (measured by HOMA) was dependent on BMI and WC at a significance level of p < 0.001 and 0.043 respectively. Therefore, the psoriatic patients in this region have significantly high amount of fasting serum insulin level along with an increased IR though their FBG level remains normal. Furthermore, these abnormalities are significantly dependent on total body fat as well as abdominal fat deposits. We suggest that psoriatic patients need to be evaluated for metabolic syndrome and managed accordingly.

Alteration of micronutrient status in compensated and decompensated liver cirrhosis.

Decompensation followed by death is the most serious outcome in patients suffering from cirrhosis of the liver. Alteration of trace elements may play a vital role in the process of decompensation. To examine the change in status of trace elements during the decompensation process, we analysed the zinc, copper, iron, magnesium, bilirubin and albumin levels in the serum of compensated (n = 34) and decompensated (n = 31) liver cirrhosis patients and compared them with healthy control group (n = 36) by post hoc ANOVA. We observed significant alteration in the selected micronutrients in the diseased group relative to healthy controls (P < 0.05). Moreover, mean serum zinc and iron levels were significantly lower with a higher level of serum copper in decompensated cirrhosis group than in compensated group (P < 0.05). However, no significant decrease of serum magnesium was found between the two diseased groups. Our findings imply that the trace elements like zinc, copper and iron might exert important contributory roles in decompensation process in liver cirrhosis and hence, may be utilized as important biomarkers for these patients. Furthermore, we propose that replacements of those micronutrients at an early stage can delay or prevent the severe outcomes like hepatic encephalopathy, gastrointestinal bleeding, severe jaundice or ascites in these patients.

Association of angiotensin converting enzyme gene insertion/deletion polymorphism with diabetic retinopathy in middle-aged Indians with type 2 diabetes mellitus.

OBJECTIVES: There are conflicting reports regarding the association of angiotensin 1 converting enzyme (ACE) gene polymorphism with diabetic retinopathy (DR). We compared ACE gene insertion/deletion (I/D) polymorphism between patients with and without DR in a middle-aged Indian population. The secondary outcome measure was the comparison of ACE gene I/D polymorphism in different grades of DR severity. METHODS: Institutional cross-sectional case-control study with middle-aged (45-64 years) type 2 diabetes patients from Eastern India with DR (DR group) and without DR (NODR group). Polymerase chain reaction (PCR) was used to determine the ACE gene I/D polymorphism through primers flanking the polymorphic region of 287 bp Alu repeat sequence in intron 16. RESULTS: Genotyping for the ACE gene I/D polymorphisms were done for 107 patients in each group. The presence of DR had no significant association with the prevalence of ACE I/D genotype compared to those without DR either in the recessive model (p=0.588) or in the dominant model (p=0.891). The allele contrast was also similar between DR and NODR (p=0.837) groups. The severity of retinopathy was associated with the ACE I/D genotype in the recessive model (p=0.043) but not in the dominant model (p=0.136). However, the severity of retinopathy was associated with allele contrast (p=0.016). CONCLUSIONS: The ACE gene polymorphism was not associated with diabetic retinopathy in middle-aged Indian patients with type 2 diabetes in our study. However, the severity of DR was associated with the ACE gene polymorphism in these patients.

Association of Diabetic Retinopathy with Midlife Hepatic Steatosis Diagnosed by Elastography and Hepatic Steatosis Index in Type 2 Diabetes in an Indian Population.

Aims: People with type 2 diabetes mellitus are at increased risk of developing hepatic steatosis. We determined the prevalence of hepatic steatosis in middle-aged patients with and without diabetic retinopathy (DR) in an Indian population. We feel this information is critical, with trends of increasing chronic liver disease-related mortality at younger ages. Method: Institution-based analytical cross-sectional study with 114 middle-aged type 2 diabetes patients; 57 in each group with <15 years of duration of DM and without excessive drinking. Hepatic steatosis was determined by the hepatic steatosis index (HSI), hepatic ultrasonography (USG), and elastography. Result: The HSI in DR (37.9 ± 3.9) was more (P = 0.012) than in without diabetic retinopathy (NODR) (36.3 ± 3.3). There was no difference between two groups in liver span (P = 0.829) or in the prevalence of fatty liver (P = 0.562) as determined by conventional USG. Elastography value (kPa) was more (P = 0.001) in DR (6.51 ± 1.85) than in NODR (5.14 ± 1.60). On elastography, 50.9% in DR had a likelihood ratio (Metavir score for a stiffness value) for stage 2 Metavir score. In DR, 11.8% of those missed by USG had a likelihood ratio for ≥ stage 2 Metavir score on elastography. The presence of DR was independently correlated with kPa value (P < 0.001). Conclusion: A significantly higher prevalence of hepatic steatosis was observed in DR in this population. DR can be a useful biomarker for early hepatic screening in midlife, particularly with hepatic elastography, so that timely diagnosis of hepatic steatosis can be made.

Comparison of urinary and serum CA 19-9 as markers of early stage urothelial carcinoma.

OBJECTIVES: Although the glycoprotein group tumor marker CA 19-9 has been detected in both serum and urine of bladder cancer patients, information about their comparative role in screening of low grade transitional cell carcinoma (LGTCC) and high grade transitional cell carcinoma (HGTCC) is rare. MATERIALS AND METHODS: In this study we measured both the urinary and serum levels of CA 19-9 in 35 LGTCC and 20 HGTCC patients by ELISA and determined the cut off value of both urinary and serum CA 19-9 levels by receiver operator characteristic curve (ROC) for both patient groups. Odds ratio (OR) for CA 19-9 was analyzed with its range at 95% confidence interval to analyze the role of this tumor marker as a screening parameter for both of these cancer types. RESULTS: For urinary CA 19-9 the OR was 20.16 with an interval of 4.91-82.71 whereas for the serum CA 19-9 it was 7.5 with an interval of 2.28-24.62. CONCLUSIONS: From these data we suggest that urinary CA 19-9 is a better screening parameter with optimum sensitivity and specificity than its serum counterpart for diagnosis of low grade and early stages of transitional cell carcinoma of urinary bladder. Furthermore, it can be suggested that urinary CA 19-9 can be used as better prognostic marker for LGTCC than its serum counterpart.

Diagnostic Role of Tumour Markers CEA, CA15-3, CA19-9 and CA125 in Lung Cancer.

The aim of this study was to assess the diagnostic yield of the tumour markers carcinoembryonic antigen, carbohydrate antigen 15-3, carbohydrate antigen 19-9 and carbohydrate antigen 125, in serum and bronchoalveolar lavage fluid in a group of patients with bronchogenic carcinoma. Serum and bronchoalveolar lavage fluid samples were collected in a group of 90 patients with benign or malignant pulmonary diseases. After appropriate processing, tumour markers were determined by enzyme immunoassay. The diagnostic yields (sensitivity, specificity and predictive values) in each environment (serum and bronchoalveolar lavage fluid) were obtained by using "Receivers operating characteristic" curve. Determined individually, carcinoembryonic antigen, carbohydrate antigen 19-9 and carbohydrate antigen 125, showed the greatest diagnostic accuracy in bronchoalveolar lavage fluid. Carbohydrate antigen 15-3 did so in serum. Carcinoembryonic antigen was the most relevant marker in bronchoalveolar lavage fluid. For the factors evaluated in this study, determination of carcinoembryonic antigen, carbohydrate antigen 19-9 and carbohydrate antigen 125 in bronchoalveolar lavage fluid were clinically more useful markers in comparison with serum, although the latter may also be helpful in certain situations. Although there is no specific tumour marker for lung cancer, the combination of several can be used to diagnose most patients with lung cancer and also to rule out false positive and negative cases.

Predictors of insulin resistance and metabolic complications in polycystic ovarian syndrome in an eastern Indian population.

The purpose of this study was to assess the predictive values of central obesity and hyperandrogenemia in development of insulin resistance and dyslipidemia in the polycystic ovarian syndrome (PCOS) patients in our region. Differences of fasting blood glucose level, insulin resistance index HOMA-IR, lipid parameters, waist hip ratio (WHR), body mass index, LH/FSH ratio and testosterone levels between 45 PCOS cases and 35 age matched controls were obtained. Strength of association between different parameters in the case group was assayed by Pearson's correlation analysis. Dependence of insulin resistance and WHR on different predictors was assessed by multiple linear regression assay. Total cholesterol, LDL cholesterol, LH, FSH, LH/FSH ratio, WHR and insulin resistance were significantly higher in the case group (p < 0.05). Serum testosterone showed strong correlation with insulin resistance and LH/FSH ratio (r = 0.432 and 0.747, p = 0.01 and 0.001 respectively) in the PCOS patients while WHR and serum testosterone level stood out to be most significant predictors for the insulin resistance (ß = 0.361 and 0.498; p = 0.048 and 0.049 respectively). Hyperandrogenemia and central obesity were the major factors predicting development of insulin resistance and its related metabolic and cardiovascular complications in our PCOS patients. We suggest early monitoring for androgen level and WHR in these patients for predicting an ensuing insulin resistance and modulating the treatment procedure accordingly to minimise future cardiovascular risks.

Vaccine-induced control of viral shedding following rhesus cytomegalovirus challenge in rhesus macaques.

The use of animal models of human cytomegalovirus (HCMV) infection is critical to refine HCMV vaccine candidates. Previous reports have demonstrated that immunization of rhesus monkeys against rhesus cytomegalovirus (RhCMV) can reduce both local and systemic replication of RhCMV following experimental RhCMV challenge. These studies used prime/boost combinations of DNA expression plasmids alone or DNA priming and boosting with either inactivated virion particles or modified vaccinia virus Ankara (MVA) expressing the same antigens. Viral outcomes included reduced RhCMV replication at the site of subcutaneous inoculation and RhCMV viremia following intravenous inoculation. Since shedding of cytomegalovirus from mucosal surfaces is critical for horizontal transmission of the virus, DNA priming/MVA boosting was evaluated for the ability to reduce oral shedding of RhCMV following subcutaneous challenge. Of six rhesus monkeys vaccinated exclusively against RhCMV glycoprotein B (gB), phosphoprotein 65 (pp65), and immediate-early 1 (IE1), half showed viral loads in saliva that were lower than those of control monkeys by 1 to 3 orders of magnitude. Further, there was a strong association of memory pp65 T cell responses postchallenge in animals exhibiting the greatest reduction in oral shedding. These results highlight the fact that a DNA/MVA vaccination regimen can achieve a notable reduction in a critical parameter of viral replication postchallenge. The recently completed clinical trial of a gB subunit vaccine in which the rate of HCMV infection was reduced by 50% in the individuals receiving the vaccine is consistent with the results of this study suggesting that additional immunogens are likely essential for maximum protection in an outbred human population.

Association of the Val66Met polymorphism of the BDNF gene and the deletional mutation of CYP2D6 gene with the prevalence and severity of depressive disorder in an Eastern Indian population.

Background: The Val66Met single nucleotide polymorphism (SNP) of the brain-derived growth factor (BDNF) and deletional mutation of the cytochrome P4502D6 (CYP2D6) have been reported to be linked to the etiology and severity of depressive disorders (DD) in a variable manner among different ethnicities and populations. Aims: The present study was aimed to find the relationship of mutational variations of these two neurotrophins with the severity of DD and their serum cortisol levels as a marker of the stress factor. Methods: In 104 drug-naïve newly diagnosed cases of DD and 106 control subjects, the severity of depression was assessed using the HAM-D score. Val66Met SNP of the BDNF was analyzed in them using restriction digestion of its polymerase chain reaction (PCR) product. CYP2D6 deletional variants were detected by the absence of their PCR products. Serum cortisol levels were measured by the enzyme-linked immunosorbent assay (ELISA) technique. Results: The Chi-square test (Χ2 = 1.42, P = 0.49) did not show any higher prevalence of Val66Met SNP of the BDNF gene in the case group. A correlation coefficient (R) of -0.14 for HAM-D score with a P value of 0.29 signified no direct link of the severity of DD with this SNP. However, a Χ2 of 12.68 with P < 0.001 indicated a significantly higher prevalence of the CYP2D6 deletional mutants in DD cases, whereas an R-value of 0.39 for HAM-D score with P < 0.001 suggested a significantly higher severity of DD having with them. Serum cortisol level showed a significant positive correlation with the deletional variants of CYP2D6 (R = 0.198, P = 0.04) and the HAM-D score (R = 0.22, P = 0.025). Conclusion: We conclude that CYP2D6 deletion significantly contributes to the severity and stress factor in the DD patients in our study population. Early identification of these mutations may provide important molecular and cellular predisposition for the disease and may lay the ground for possible more effective measures of intervention.

Monkeypox virus evades antiviral CD4+ and CD8+ T cell responses by suppressing cognate T cell activation.

Monkeypox virus (MPV) is a virulent human pathogen that has gained increased attention because of its potential use as a bioterrorism agent and inadvertent introduction into North America in 2003. The US outbreak also provided an important opportunity to study MPV-specific T cell immunity. Although MPV-specific CD4(+) and CD8(+) T cells could recognize vaccinia virus (VV)-infected monocytes and produce inflammatory cytokines such as IFNgamma and TNFalpha, they were largely incapable of responding to autologous MPV-infected cells. Further analysis revealed that, unlike cowpox virus (CPV), MPV did not interfere with MHC expression or intracellular transport of MHC molecules. Instead, MPV-infected cells were capable of preventing T cell receptor (TcR)-mediated T cell activation in trans. The ability to trigger a state of nonresponsiveness represents a unique MHC-independent mechanism for blocking antiviral T cell activation and inflammatory cytokine production and is likely an important attribute involved with viral dissemination in the infected host.

Impact of pH on growth of Staphylococcus epidermidis and Staphylococcus aureus in vitro.

The pH of skin is critical for skin health and resilience and plays a key role in controlling the skin microbiome. It has been well reported that under dysbiotic conditions such as atopic dermatitis (AD), eczema, etc. there are significant aberrations of skin pH, along with a higher level of Staphylococcus aureus compared to the commensal Staphylococcus epidermidis on skin. To understand the effect of pH on the relative growth of S. epidermidis and S. aureus, we carried out simple in vitro growth kinetic studies of the individual microbes under varying pH conditions. We demonstrated that the growth kinetics of S. epidermidis is relatively insensitive to pH within the range of 5-7, while S. aureus shows a stronger pH dependence in that range. Gompertz's model was used to fit the pH dependence of the growth kinetics of the two bacteria and showed that the equilibrium bacterial count of S. aureus was the more sensitive parameter. The switch in growth rate happens at a pH of 6.5-7. Our studies are in line with the general hypothesis that keeping the skin pH within an acidic range is advantageous in terms of keeping the skin microbiome in balance and maintaining healthy skin.

Regulatory Framework for Academic Investigator-Sponsored Investigational New Drug Development of Cell and Gene Therapies in the USA.

PURPOSE OF REVIEW: The promise of cell and gene therapy (CGT) products for a multitude of diseases has revitalized investigators to advance novel CGT product candidates to first-in-human trials by pursuing the investigational new drug (IND) mechanism administered by the United States (US) Food and Drug Administration (FDA). This review is intended to familiarize academic investigators with the IND governing regulations set forth by the FDA. RECENT FINDINGS: CGT products are extraordinarily complex biologics and, therefore, early-stage evaluation programs must be customized to satisfactorily address their unique developmental challenges. The US FDA continues to foster the development of transformational technology that will facilitate the broad application of safe and effective gene therapy products that have the potential to alleviate many conditions previously out of reach of therapeutic intervention. FDA is committed to working with the scientific community and industry to facilitate the availability of these treatments to patients. SUMMARY: The pathway to meet regulatory compliance during early stage IND programs can be daunting to academic investigators interested in CGT product development that typically don't progress beyond phase 1/2. However, by keeping abreast of current regulatory framework and building upon FDA's supportive infrastructure, an investigator can be well-positioned to advance innovative scientific discoveries towards early stage clinical assessments.