Aminolevulinic Acid

Background  Photodynamic therapy (PDT) is based on the combination of an exogenously administered precursor of photosensitizer [protoporphyrin IX (PpIX)] synthesis and exposure to light. Choosing the optimal wavelength is important. Red light penetrates deeper into tissue, while violet light is more efficient in activating PpIX but does not penetrate so deeply.Objectives  We studied PpIX formation and the PDT effect after application to human skin of creams containing aminolaevulinic acid (ALA) and aminolaevulinic acid methyl ester (MAL). The aim of the study was to investigate whether the wavelength of the light used has an influence on pain sensations during topical PDT with the different prodrugs.Methods  ALA cream (10%) and MAL cream (10%) were topically applied on the skin of 10 healthy volunteers. After 24 h the application site was exposed to 8 mW cm−2 violet laser or to 100 mW cm−2 red laser light. The erythema index was monitored up to 24 h after light exposure. For the first time the pain during topical ALA- and MAL-PDT was assessed by measuring the time taken for pain to occur. Also, for the first time, the intensities of the light sources were calibrated so as to have the same relative quantum efficiency.Results  The pain sensation during ALA-PDT with red light came 22 s sooner than during ALA-PDT with violet light, which is statistically significant (P < 0·05). Moreover, ALA-PDT with red light gave stronger and more persistent erythema than ALA-PDT with violet light. ALA induced about three times more PpIX than MAL. No statistically significant differences were found for erythema, or for the time for pain to occur, in the case of MAL-PDT with red vs. violet light.Conclusions  Topical ALA-PDT with violet light allows longer exposure times before pain is induced and gives less erythema as compared with topical ALA-PDT with red light.

Cholera caused by the O139 serogroup still remains a public health concern in certain regions of the world and the existing O1 vaccines do not cross-protect cholera caused by this serogroup. An aminolevulinic acid (ALA) auxotroph vaccine candidate against the O139 serogroup, designated as VCUSM2, was recently developed. It was found to be immunogenic in animal model studies but showed mild reactogenic effects due to the presence of two intact copies of Vibrio cholerae toxin (CTX) genetic element. In the present study we have modified the ctx operon by systematic allelic replacement methodology to produce a mutant strain, designated as VCUSM14. This strain has two copies of chromosomally integrated and mutated ctxA gene, encoding immunogenic but not toxic cholera toxin A subunit (CT-A). The amino acids arginine and glutamic acid at position 7th and 112th, respectively, in CT-A of VCUSM14 were substituted with lysine (R7K) and glutamine (E112Q), respectively. Two copies of the ace and zot genes present in the ctx operon were also deleted. Cholera toxin-ELISA using GM1 ganglioside showed that the both wild type CT and mutated CT were recognized by anti-CT polyclonal antibodies. VCUSM14 produced comparatively less amount of antigenic cholera toxin when compared to the VCUSM2 and Bengal wild type strain. VCUSM14 did not elicit fluid accumulation when inoculated into rabbit ileal loops at doses of 10(6) and 10(8) CFU. The colonization efficiency of VCUSM14 was one log lower than the parent strain, VCUSM2, which can be attributed to the ALA auxotrophy and less invasive properties of VCUSM14. VCUSM14, thus a non-reactogenic auxotrophic vaccine candidate against infection by O139 V. cholerae.

Recent studies have shown that photodynamic therapy (PDT) is effective in the treatment of acne vulgaris. No studies have compared the treatment effect of aminolevulinic acid-PDT (ALA-PDT) and methyl aminolevulinate-PDT (MAL-PDT). We sought to compare the treatment effect and tolerability of ALA-PDT versus MAL-PDT in the treatment of acne vulgaris in a controlled randomized investigator-blinded trial. Fifteen patients with at least 12 facial inflammatory acne lesions had one split-face PDT treatment with MAL and ALA. Twelve weeks after treatment we found a 59% decrease in inflammatory lesions from baseline, with no significant differences in effectiveness between the two treatments. All patients experienced moderate to severe pain during illumination and developed erythema, pustular eruptions, and epithelial exfoliation after treatment, which were more severe and uniform in the ALA-PDT-treated area. The study is paired and controlled, but the results should be evaluated with consideration given for the number of participating patients. PDT appeared to be an effective treatment for inflammatory acne vulgaris with no significant differences in the response rate between ALA-PDT and MAL-PDT. ALA-PDT resulted in more prolonged and severe adverse effects after treatment.

BackgroundHigh efficacy and safety, coupled with in-office, short contact protocols have made photodynamic therapy (PDT) with aminolevulenic acid (ALA) for the treatment of actinic keratoses a mainstay option over the last decade. Clinical improvement in photoaged skin has also been reported to accompany PDT treatments. The study objective was to maximize epidermal penetration and subsequent activation of ALA for the treatment of photodamaged facial skin, utilizing a microneedle roller prior to incubation and combined irradiation with red light and broadband pulsed light in a single treatment.High efficacy and safety, coupled with in-office, short contact protocols have made photodynamic therapy (PDT) with aminolevulenic acid (ALA) for the treatment of actinic keratoses a mainstay option over the last decade. Clinical improvement in photoaged skin has also been reported to accompany PDT treatments. The study objective was to maximize epidermal penetration and subsequent activation of ALA for the treatment of photodamaged facial skin, utilizing a microneedle roller prior to incubation and combined irradiation with red light and broadband pulsed light in a single treatment.Materials and MethodsA full-face treatment of 21 patients was performed with 630 nm light and broadband pulsed light after multiple passes with a microneedle roller and 1-hour ALA incubation. The primary endpoint was clinical improvement, scored during two separate live assessments by three physicians blinded to previous scores, using a 5-point standardized photoaging scale. The secondary endpoint was evaluation of patient satisfaction based on a quartile scale comparing baseline to 6-month post-treatment photography.A full-face treatment of 21 patients was performed with 630 nm light and broadband pulsed light after multiple passes with a microneedle roller and 1-hour ALA incubation. The primary endpoint was clinical improvement, scored during two separate live assessments by three physicians blinded to previous scores, using a 5-point standardized photoaging scale. The secondary endpoint was evaluation of patient satisfaction based on a quartile scale comparing baseline to 6-month post-treatment photography.ResultsStatistically significant improvement was seen in the global photoaging scores, as well as sub-components of the scale (fine lines, mottled pigmentation, sallowness, tactile roughness, and telangiectasias) at 3 months as compared with baseline live assessment, and at 6-month live assessment compared with the 3 months. In addition, 90% of patients judged clinical improvement to be greater than 50% at 6 months compared to baseline photography.Statistically significant improvement was seen in the global photoaging scores, as well as sub-components of the scale (fine lines, mottled pigmentation, sallowness, tactile roughness, and telangiectasias) at 3 months as compared with baseline live assessment, and at 6-month live assessment compared with the 3 months. In addition, 90% of patients judged clinical improvement to be greater than 50% at 6 months compared to baseline photography.ConclusionUse of a microneedle roller to “pre-treat” prior to application of ALA appears to be well tolerated and allows for even absorption and perhaps deeper penetration of ALA following a defined incubation period. Use of red light and broadband pulsed light allowed for deeper activation of ALA, potentially accounting for marked clinical improvement in photoaging. Lasers Surg. Med. 42:150–159, 2010. © 2010 Wiley-Liss, Inc.Use of a microneedle roller to “pre-treat” prior to application of ALA appears to be well tolerated and allows for even absorption and perhaps deeper penetration of ALA following a defined incubation period. Use of red light and broadband pulsed light allowed for deeper activation of ALA, potentially accounting for marked clinical improvement in photoaging. Lasers Surg. Med. 42:150–159, 2010. © 2010 Wiley-Liss, Inc.

Photodynamic therapy (PDT) is a tool for the treatment of certain cancerous and pre-cancerous conditions in dermatology. 5-Aminolevulinic acid (5-ALA) and simple derivatives thereof are the principal compounds used for this purpose. For optimal efficacy, the drug must be released at an appropriate rate from the formulation and penetrate the skin, ideally to reach the target tissue at a sufficiently

The aim of this study was to examine the in vitro skin delivery and in vivo protoporphyrin IX (PpIX) accumulation of topically applied 5-aminolevulinic acid (ALA) enhanced by a fractional laser pretreatment. This was achieved by applying an array of microscopic treatment zones (MTZ) to the skin by ablation of superficial stratum corneum in a determined area. Re-epithelialization determined by transepidermal water loss was completed within 1 day after fractional laser irradiation. The conventional laser used in comparison showed more severe skin disruption and a greater recovery duration of 2 days. The in vitro ALA permeation was measured using a Franz cell apparatus, with nude mouse skin and porcine skin as the permeation barriers. The efficacy of the enhancement was determined as a function of various laser fluences (2 and 3 J/cm(2)) and number of passes (1-6 passes). The flux of ALA via laser-treated nude mouse skin was 27-124-fold higher than that across intact skin. A 3-260-fold increase in ALA flux was detected by using the porcine skin as the permeation barrier. The skin permeation was also investigated in a model of hyperproliferative skin obtained by repeated tape stripping. The results showed that the hyperproliferative skin was more permeable to ALA in comparison to the normal skin. The in vivo localization of PpIX in nude mouse skin was imaged using confocal laser scanning microscopy. As expected, an intense red fluorescence was observed in the lower epidermis and upper dermis after fractional laser irradiation. The penetration depth was also increased by the laser. The safety and efficacy of enhancing ALA permeation were demonstrated by using the fractional laser at low fluences.

Photosensitization, an exaggerated sensitivity to harmless light, occurs genetically in rare diseases, such as porphyrias, and in photodynamic therapy where short-term toxicity is intended. A common feature is the experience of pain from bright light. In human subjects, skin exposure to 405 nm light induced moderate pain, which was intensified by pretreatment with aminolevulinic acid. In heterologous expression systems and cultured sensory neurons, exposure to blue light activated TRPA1 and, to a lesser extent, TRPV1 channels in the absence of additional photosensitization. Pretreatment with aminolevulinic acid or with protoporphyrin IX dramatically increased the light sensitivity of both TRPA1 and TRPV1 via generation of reactive oxygen species. Artificial lipid bilayers equipped with purified human TRPA1 showed substantial single-channel activity only in the presence of protoporphyrin IX and blue light. Photosensitivity and photosensitization could be demonstrated in freshly isola...

The glycopeptide teicoplanin isolated from the fermentation broth of Actinoplanes teichomyceticus is used to treat serious Gram-positive bacterial infections that are resistant to other antibiotics, e.g. β-lactams. The long time frame and progressively broader clinical use of teicoplanin has eventually led to the emergence and spreading of resistance in enterococci and staphylococci towards the antibiotics. Given the structural complexity of the natural product, only fermentative routes are available for bulk production of teicoplanin even though the total synthesis of the antibiotic has been accomplished. Because the low productivity (0.1–3.1 g/L) is a limitation to the commercial production of teicoplanin, substantial effort has been devoted to the strain improvement and process development for enhancing the productivity. This review summarizes the current state of the action mechanism, antibacterial activity, resistance mechanism, biotechnological production, and application of teicoplanin.

Acute intermittent prophyria (AIP) is an autosomal dominant disease that results from a defect in the enzyme porphobilinogen deaminase. Acute intermittent porphyria is the most common of hepatic porphyrias and can tax the therapeutic capabilities of the physician to the limit. Motor weakness is a major feature of an acute attack, and flaccid paralysis of all extremities can occur rapidly, within a matter of days. The acute attacks may be life threatening. Hematin (Heme Arginate) should be given early during an acute attack to prevent neurologic sequel. Hemodialysis and hemoperfusion have been tried in the treatment of acute attacks of AIP with success. As hematin is not available in India, a severe acute attack of AIP in a patient was managed with hemodialysis successfully. Later, hematin was imported and provided to the patient. An 18-year-old girl was admitted to our hospital with recurrent abdominal pain and 2 episodes of convulsions. She had undergone an appendectomy earlier at another hospital for abdominal pain. On evaluation, she had hyponatremia, episodic abnormal behavior, generalized muscle pain, hypertension, and sinus tachycardia. In view of the above clinical picture, a clinical diagnosis of acute intermittent porphyria was made. Her 24-hr urinary porphobilinogen was 90.8 mg/day (<2 mg—normal) and α amino levalunic acid was 108.8 mg/day (1–7 mg—normal), consistent with the diagnosis. Her hyponatremia was corrected. Arrangements were made to import hematin and she was managed with dextrose infusion. Meanwhile, she developed flaccid quardriparesis with urinary incontinence and bulbar palsy. Her brain MRI was normal. Her nerve conduction study was suggestive of motor radiculoneuropathy. Specific treatment for severe porphyric crisis was planned. She failed to improve with dextrose infusion alone. As hematin was not readily available in the country, other therapeutic options were considered. As few case reports of AIP being successfully treated with hemodialysis were available, the option of dialytic support was explained to the family. After procuring informed consent, she was subjected to hemodialysis for 4 hr in the first day, increasing to 6 hr a day for the next 6 days. Her abdominal pain and myalgia subsided on the third day of dialysis. Her lower limb muscle power improved and she became ambulant by the fourth day. Urinary retention improved within 4 days. Hematin was imported by then from the United States. Later, 2 doses of hematin (4 mg/kg–160 mg in 20% albumin) were given via a central vein. She was maintained on physiotherapy. Repeat nerve conduction study revealed recovery. She has been provided with a list of drugs that have to be avoided. Currently, she is on outpatient follow-up with occasional abdominal pain, which subsides with intravenous dextrose therapy.

By means of a chemical extraction procedure and confocal laser scanning microscopy, we investigated the kinetic patterns of uptake and biolocalization of 5-aminolevulinic acid (ALA)-induced porphyrins in s.c. transplanted tumors, adjacent normal skin and muscle, and liver of mice bearing mammary carcinoma, after i.p. injection of 250 mg/kg ALA or topical application of ALA (20% in an oil-in-water emulsion). Furthermore, we evaluated the tumor responses after either i.p. injection or topical application of 5-ALA followed by laser irradiation (632 nm, 150 mW/cm2, 25 min) by measuring the treated tumor regression/regrowth time and by light and electron microscopy. Strong fluorescence of ALA-induced porphyrins was detected in the tumor, skin and liver tissues, while little fluorescence was seen in the adjacent muscle tissue. Moreover, the highest amounts of ALA-induced porphyrins in the tumor and skin tissues were found 1 hr after i.p. injection, whereas the amounts of the porphyrins in both tissues increased with increasing time after topical application of ALA. The fluorescence of the porphyrins was localized in several components of the skin tissue (epidermis, hair follicles and their associated sebaceous glands). Furthermore, the fluorescence was diffusely distributed in the s.c. transplanted tumor tissue. Little could be observed under a confocal laser scan microscope (CLSM) in the muscle tissue. The uptake and biolocalization data correlate well with the results of PCT efficiency of the same tumor model with ALA-induced porphyrins. Light and electron microscopy showed that the mitochondria of the tumor cells and of the endothelial cells and the basal lamina of vascular walls beneath the endothelium in the tumor tissue were initially extensively destroyed after PCT with ALA-induced porphyrins. Thereafter, diffuse degeneration followed by local and/or diffuse severe necrosis of the tumor cells was found. This may be due mainly to the initial damage to mitochondria in the cancerous and endothelial cells and also to the destruction of the vascular wall in the tumor tissue. © 1992 Wiley-Liss, Inc.