Anti-cancer effectiveness of a novel ceramide analog on chemo-sensitive and chemo-resistant breast cancers.

INTRODUCTION: Ceramides are known to show anti-cancer activity. A novel ceramide analog, (S,E)-3-hydroxy-2-(2-hydroxybenzylidene)amino-N-tetradecylpropanamide (analog 315) was developed as part of a larger study focused on finding more effective breast cancer treatments. OBJECTIVE: To assess whether analog 315 shows any or a combination of the following effects in breast cancer cells in vitro: inhibiting proliferation, inducing apoptosis, and altering protein expression. Also, to determine whether it inhibits chemo-resistant breast cancer tumor growth in vivo mouse model. METHODS: In vitro cell proliferation and apoptosis after treatment with analog 315 were assessed in three breast cancer cell lines (MCF-7, MCF-7TN-R, and MDA-MB-231) and reported. Protein expression was assessed by microarray assay. For the in vivo studies, chemo-resistant breast cancer cells were used for tumor development in two groups of mice (treated and control). Analog 315 (25 mg/kg/day) or control (dimethyl sulfoxide) was administered intraperitoneally for 7 days. Effects of analog 315 on inhibiting the growth of chemo-resistant breast cancer tumors after treatment are reported. RESULTS: Analog 315 reduced MCF-7TN-R chemo-resistant tumor burden (volume and weight) in mice. Liver metastasis was observed in control mice, but not in the treated animals. Ki-67, a proliferation marker for breast cancer cells, increased significantly ( P  < 0.05) in control tumor tissue. In vitro studies showed that analog 315 inhibited cell proliferation, altered protein expression and induced apoptosis in all three breast cancer cell lines studied, of which the effects on MCF-7TN-R cells were the most significant. CONCLUSION: Analog 315 reduced tumor growth in chemo-resistant breast cancer, inhibited cell proliferation, altered protein expression, and induced apoptosis in all three cell lines studied.

Novel bone-targeted parathyroid hormone-related peptide antagonists inhibit breast cancer bone metastases.

Patients with advanced breast cancer often develop bone metastases. Treatment is limited to palliative care. Parathyroid hormone (PTH)/parathyroid hormone-related peptide (PTHrP) antagonists for bone metastases failed clinically due to short half-life and inadequate concentration in bone. We synthesized two novel PTHrP antagonists fused to an inert bacterial collagen binding domain (CBD) that directs drugs to bone. PTH(7-33)-CBD is an N-terminal truncated PTHrP antagonist. [W2]PTH(1-33)-CBD is an PTHrP inverse-agonist. The aim of this study was to assess PTH(7-33)-CBD to reduce breast cancer bone metastases and prevent osteolytic destruction in mice and to assess both drugs for apoptosis of breast cancer cells in vitro and inhibition of PTH receptor (PTHR1). PTH(7-33)-CBD (1000 µg/kg, subcutaneous) or vehicle was administered 24 h prior to MDA-MB-231 breast cancer cell inoculation into the tibia marrow. Weekly tumor burden and bone density were measured. Pharmacokinetic analysis of PTH(7-33)-CBD in rat serum was evaluated. Drug effect on cAMP accumulation in SaOS-2 osteosarcoma cells and apoptosis of MDA-MB-231 cells was assessed. PTH(7-33)-CBD reduced MDA-MB-231 tumor burden and osteolytic destruction in mice 4-5 weeks post-treatment. PTH(7-33)-CBD (1000 µg/kg i.v. and subcutaneous) in rats was rapidly absorbed with peak concentration 5-min and terminal half-life 3-h. Bioavailability by the subcutaneous route was 43% relative to the i.v. route. PTH(7-33)-CBD was detected only on rat periosteal bone surfaces that stained positive for collagen-1. PTH(7-33)-CBD and [W2]PTH(1-33)-CBD (10-8M) blocked basal and PTH agonist-induced cAMP accumulation in SaOS-2 osteosarcoma cells. Both drugs induced PTHR1-dependent apoptosis of MDA-MB-231 cells in vitro. Novel bone-targeted PTHrP antagonists represent a new paradigm for treatment of breast cancer bone metastases.

Inhibition of breast tumor growth in mice after treatment with ceramide analog 315.

The aim of this study was to evaluate the anticancer and antitumor activities of ceramide analog 315 in nude mice. Nude mice (n=10) were injected bilaterally with 5×10 MDA-MB-231 cells on each side. Tumors were allowed to form for 2 weeks. The mice were then divided into two groups (n=5 in each group). The control group mice were injected with 25 µl of dimethyl sulfoxide and the treatment group mice were injected with 10 mg/kg of analog 315 (in dimethyl sulfoxide, 25 µl volume) every day for a period of 3 weeks. Animal weights and tumors were measured every week for 3 weeks. At the end of the experimental period, control animals had retained excess fluid, and showed larger tumor sizes compared with the treated group (2.95 vs. 1.67 g). A 45% reduction in tumor size and 80% decrease in tumor volume were observed in the treatment group. There was a significant increase in the weights of liver (10%) and spleen (19%) between the control and treated animals. Hematoxylin and Eosin staining of MDA-MB-231 tumor sections revealed more acellular necrotic regions in tumors from the treatment groups compared with the ones from the control group. Ki67, a proliferation marker was higher in number in control tumor section (71.8±12.8) compared to the treatment tumor section (37.4±10.4) (P<0.001). Photomicrographs showed metastatic tumor burden in kidney, lungs, and spleen collected from the control group mice bearing MDA-MB-231 tumors. Treatment group mice showed normal microscopic tissue architecture. Overall, our study showed tumor growth inhibition and antimetastatic effects for the novel ceramide analog 315.

Treatment of Vitamin D Deficiency in Predominantly Hispanic and Black Adolescents: A Randomized Clinical Trial.

OBJECTIVES: To compare 3 different treatment regimens for vitamin D deficiency in minority adolescents and to explore factors that impact treatment efficacy. STUDY DESIGN: We conducted an 8-week, prospective, open-label, randomized clinical trial in an urban, academic, children's hospital. A total of 183 vitamin D-deficient adolescents, mean 25-hydroxyvitamin D or 25(OH)D 13.7 ± 3.9 ng/mL; mean age 16.6 ± 2.2 years, were randomized into 3 vitamin D3 (cholecalciferol) treatment arms: 50,000 IU/wk; 5000 IU/d; and 1000 IU/d. Serum 25(OH)D and vitamin D binding protein (VDBP) levels were measured pre-and posttreatment; 122 (67%) participants completed posttreatment measures. Complete-case and multiple-imputation, intention-to-treat analyses were performed. RESULTS: Mean change in 25(OH)D level posttreatment was significantly different among the 3 arms, 24.9 ± 15.1 vs 21.0 ± 15.2 vs 6.2 ± 6.5 ng/mL, for 50,000 IU, 5000 IU, and 1000 IU doses, respectively, P < .001. Both high-dose treatments were effective in increasing the 25(OH)D level out of deficiency range (≥ 20 ng/mL) in more than 80% of participants, and 60% remained deficient after low-dose treatment. Only 72%, 56%, and 2% achieved vitamin D sufficiency (>30 ng/mL) with 50,000 IU, 5000 IU, and 1000 IU doses, respectively, P < .001. Obese participants had substantially less mean change in 25(OH)D level after treatment than normal-weight participants, 13.7 ± 10.7 vs 21.9 ± 16.9 ng/mL, P < .001. Mean baseline VDBP level was almost twice as high in Hispanic compared with black participants (P < .001) and did not alter treatment response or change with treatment. CONCLUSIONS: Adult-sized adolescents require 8 weeks of high-dose cholecalciferol, at least 5000 IU/d, to correct deficiency. Obese adolescents have poorer response to treatment and may need higher doses than nonobese youth. Hispanic and black adolescents have different VDBP levels but similar treatment responses. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01784029.

Therapy for Alopecia Areata in Mice by Stimulating the Hair Cycle with Parathyroid Hormone Agonists Linked to a Collagen-Binding Domain.

UNLABELLED: Alopecia areata is a common disorder in which autoimmune destruction of hair follicles results in patchy hair loss. Currently there is no adequate therapy, although immune modulator therapies are currently in development. Parathyroid hormone (PTH) is a hair cycle stimulator which shows promise in treating various forms of alopecia, although its short half-life limits its clinical use. PTH-CBD is a PTH analog which binds collagen, prolonging retention in skin. We tested effects of PTH-CBD in C3H/HeJ-engrafted mice, the animal model for alopecia areata, on hair growth and found that a significant proportion of animals had reduced hair loss (PTH-CBD: 13/21, 62% vs. CONTROL: 3/10, 30%; P<0.01). Histological analysis showed no change in immune response, but there was increased number of anagen hair follicles and increased production of beta-catenin, a factor which initiates the anagen phase of the hair cycle. PTH-CBD thus shows promise as a therapy for alopecia areata, either alone or in conjunction with immune modulation therapy.

Treatment and prevention of chemotherapy-induced alopecia with PTH-CBD, a collagen-targeted parathyroid hormone analog, in a non-depilated mouse model.

Alopecia is a psychologically devastating complication of chemotherapy for which there is currently no effective therapy. PTH-CBD is a collagen-targeted parathyroid hormone analog that has shown promise as a therapy for alopecia disorders. This study compared the efficacy of prophylactic versus therapeutic administration of PTH-CBD in chemotherapy-induced alopecia using a mouse model that mimics the cyclic chemotherapy dosing used clinically. C57BL/6J mice were treated with a single subcutaneous injection of PTH-CBD (320 mcg/kg) or vehicle control before or after hair loss developing from three courses of cyclophosphamide chemotherapy (50-150 mg/kg/week). Mice receiving chemotherapy alone developed hair loss and depigmentation over 6-12 months. Mice pretreated with PTH-CBD did not develop these changes and maintained a normal-appearing coat. Mice treated with PTH-CBD after development of hair loss showed a partial recovery. Observations of hair loss were confirmed quantitatively by gray scale analysis. Histological examination showed that in mice receiving chemotherapy alone, there were small, dystrophic hair follicles mostly in the catagen phase. Mice receiving PTH-CBD before chemotherapy showed a mix of normal-appearing telogen and anagen hair follicles with no evidence of dystrophy. Mice receiving PTH-CBD therapy after chemotherapy showed intermediate histological features. PTH-CBD was effective in both the prevention and the treatment of chemotherapy-induced alopecia in mice, but pretreatment appears to result in a better cosmetic outcome. PTH-CBD shows promise as an agent in the prevention of this complication of chemotherapy and improving the quality of life for cancer patients.

Parathyroid hormone linked to a collagen binding domain promotes hair growth in a mouse model of chemotherapy-induced alopecia in a dose-dependent manner.

Chemotherapy-induced alopecia is a major source of psychological stress in patients undergoing cancer chemotherapy, and it can influence treatment decisions. Although there is currently no therapy for alopecia, a fusion protein of parathyroid hormone and collagen binding domain (PTH-CBD) has shown promise in animal models. The aim of this study was to determine whether there are dose-dependent effects of PTH-CBD on chemotherapy-induced alopecia in a mouse model. C57BL/6J mice were waxed to synchronize hair follicles; treated on day 7 with vehicle or PTH-CBD (100, 320, and 1000 mcg/kg subcutaneous injection); and treated on day 9 with vehicle or cyclophosphamide (150 mg/kg intraperitoneally). Mice were photographed every 3-4 days and killed on day 63 for histological analysis. Photographs were quantified by gray scale analysis to assess hair content. Mice not receiving chemotherapy showed regrowth of hair 2 weeks after waxing and normal histology after 2 months. Mice receiving chemotherapy alone showed marked hair loss after chemotherapy, which was sustained for 10 days and was followed by rapid regrowth of a normal coat. Histological analysis revealed rapid cycling dystrophic anagen/catagen follicles. Animals receiving chemotherapy and PTH-CBD showed decreased hair loss and more rapid regrowth of hair than that seen with chemotherapy alone (increased hair growth by gray scale analysis, P<0.05), and the effects were dose dependent. Histologically, hair follicles in animals receiving the highest dose of PTH-CBD were in a quiescent phase, similar to that in mice that did not receive chemotherapy. Single-dose subcutaneous administration of PTH-CBD showed dose-dependent effects in minimizing hair loss and speeding up recovery from chemotherapy-induced alopecia.

Therapy for alopecia areata in mice using parathyroid hormone agonists and antagonists, linked to a collagen-binding domain.

Alopecia areata is a common form of hair loss in which autoimmune-mediated destruction of hair follicles causes patchy hair loss, for which there is no adequate therapy. Parathyroid hormone (PTH) induces the hair cycle and promotes hair growth. PTH-CBD is a fusion protein of PTH and a bacterial collagen-binding domain (CBD), leading to targeted delivery to and retention in the skin collagen. We tested the effects of a single dose of PTH-CBD (low or high dose) on an animal model for alopecia areata, the C3H/HeJ engrafted mouse. In all the treated animals, there was a rapid (1-4 days) increase in hair growth, with sustained effects observed over a 2-month period (7/10 total treated mice<40% hair loss based on gray scale analysis, vs. 2/5 in vehicle control animals). Histological examination revealed massive stimulation of anagen VI hair follicles in treated animals despite an ongoing immune response. PTH-CBD thus shows promise as a therapy for alopecia areata, likely in conjunction with a mild immune suppressant, such as hydrocortisone cream.

Study of Ceramide-Flavone Analogs Showing Self-Fluorescence and Anti-Proliferation Activities.

Background: Many current anti-cancer drugs used to treat breast cancer mediate tumor cell death through the induction of apoptosis. Cancer cells, however, often acquire multidrug-resistance following prolonged exposure to chemotherapeutics. Consequently, molecular pathways involved in tumor cell proliferation have become potential targets for pharmacological intervention. Ceramides are tumor suppressor lipids naturally found in the cell membrane, and are central molecules in the sphingolipid signalling pathway. Methods: Our lab has targeted the ceramide signaling pathway for potential pharmacological intervention in the treatment of breast cancer. Previously, we have shown that certain ceramide analogs have therapeutic potential in the treatment of chemo-sensitive and multidrug-resistant breast cancers. Using the most active analog from our previous studies as the lead compound, new analogs containing a flavone moiety were designed and synthesized. In general, flavone derivatives often show interesting pharmacological properties, and compounds based on these molecules have been found useful in many different therapeutic areas including anti-tumor, anti-coagulants, and anti-HIV therapy. Results: Synthesis and biological evaluation of five new flavonoid ceramide analogs are reported here. These compounds were also shown to be self-fluorescent, which can be useful when investigating their distribution and action in cancer cells. Conclusion: Four out of the five flavone ceramide analogs in this study showed significant anti-proliferation activities in the three cell lines studied, MDA-MB-232, MCF-7, and MCF-7TN-R; some showing varying degrees of selectivity. The mechanisms involved in cell proliferation inhibition are complicated and further studies are needed.

Treatment for chemotherapy-induced alopecia in mice using parathyroid hormone agonists and antagonists linked to a collagen binding domain.

Parathyroid hormone (PTH) agonists and antagonists have been shown to improve hair growth after chemotherapy; however, rapid clearance and systemic side-effects complicate their usage. To facilitate delivery and retention to skin, we fused PTH agonists and antagonists to the collagen binding domain (CBD) of Clostridium histolyticum collagenase. in-vitro studies showed that the agonist fusion protein, PTH-CBD, bound collagen and activated the PTH/parathyroid hormone-related peptide receptor in SaOS-2 cells. The antagonist fusion proteins, PTH(7-33)-CBD and PTH([-1]-33)-CBD, also bound collagen and antagonized PTH(1-34) effect in SaOS-2 cells; however, PTH(7-33)-CBD had lower intrinsic activity. Distribution studies confirmed uptake of PTH-CBD to the skin at 1 and 12 hr after subcutaneous injection. We assessed in vivo efficacy of PTH-CBD and PTH(7-33)-CBD in C57BL/6J mice. Animals were depilated to synchronize the hair follicles; treated on Day 7 with agonist, antagonist, or vehicle; treated on Day 9 with cyclophosphamide (150 mg/kg i.p.) or vehicle; and sacrificed on Day 39. Normal mice (no chemo and no treatment) showed rapid regrowth of hair and normal histology. Chemo+Vehicle mice showed reduced hair regrowth and decreased pigmentation; histology revealed reduced number and dystrophic anagen/catagen follicles. Chemo+Antagonist mice were grossly and histologically indistinguishable from Chemo+Vehicle mice. Chemo+Agonist mice showed more rapid regrowth and repigmentation of hair; histologically, there was a normal number of hair follicles, most of which were in the anagen phase. Overall, the agonist PTH-CBD had prominent effects in reducing chemotherapy-induced damage of hair follicles and may show promise as a therapy for chemotherapy-induced alopecia.

A single injection of the anabolic bone agent, parathyroid hormone-collagen binding domain (PTH-CBD), results in sustained increases in bone mineral density for up to 12 months in normal female mice.

Parathyroid hormone (PTH) is the most effective osteoporosis treatment, but it is only effective if administered by daily injections. We fused PTH(1-33) to a collagen binding domain (PTH-CBD) to extend its activity, and have shown an anabolic bone effect with monthly dosing. We tested the duration of action of this compound with different routes of administration. Normal young C57BL/6J mice received a single intraperitoneal injection of PTH-CBD (320 µg/kg). PTH-CBD treated mice showed a 22.2 % increase in bone mineral density (BMD) at 6 months and 12.8 % increase at 12 months. When administered by subcutaneous injection, PTH-CBD again caused increases in BMD, 15.2 % at 6 months and 14.3 % at 12 months. Radiolabeled PTH-CBD was concentrated in bone and skin after either route of administration. We further investigated skin effects of PTH-CBD, and histological analysis revealed an apparent increase in anagen VI hair follicles. A single dose of PTH-CBD caused sustained increases in BMD by >10 % for 1 year in normal mice, regardless of the route of administration, thus showing promise as a potential osteoporosis therapy.

Monthly administration of a novel PTH-collagen binding domain fusion protein is anabolic in mice.

We synthesized fusion proteins of parathyroid hormone (PTH) (1-33) and the collagen binding domain of ColH (CBD) and tested them for anabolic bone activity in mice. Two fusion proteins were synthesized, linking the carboxy terminus of PTH(1-33) either directly to the amino terminal of the CBD or to the CBD through an adjacent ColH domain (PTH-PKD-CBD). Both PTH-CBD and PTH-PKD-CBD increased cAMP accumulation in cells stably transfected with the PTH/PTHrP receptor, and both peptides bound to type 1 collagen in flow-through assays. Distribution studies indicated that the PTH-CBD was concentrated in the bone and skin, tissues with abundant collagen and blood flow. Administration of 320 µg/kg PTH-CBD either weekly (for 8 weeks) or monthly (for 6 months) to 7-week-old C57BL/6J mice resulted in a sustained increase in bone mineral density (BMD) (15% for weekly studies, 13% for monthly studies; P < 0.05). PTH-PKD-CBD showed only 5% increases in BMD after weekly administration, and, as expected, neither weekly nor monthly PTH(1-34) affected BMD. PTH-CBD increased serum alkaline phosphatase levels. Importantly, there were no significant increases in serum calcium observed. Collectively, the data suggest that PTH-CBD has a sustained anabolic effect in bone with either weekly or monthly administration. This approach of targeted delivery of PTH to bone may show promise for the treatment of disorders of low bone mass, such as postmenopausal osteoporosis.

Acute toxicity evaluation of a novel ceramide analog for the treatment of breast cancer.

We have previously reported that treating triple-negative tumor bearing nude mice with intraperitoneal (ip) 10 mg/kg body weight of (S,E)-3-hydroxy-2-(2-hydroxybenzylidene)amino-N-tetradecylpropanamide, a ceramide analog, 5 days per week for 3 weeks, was shown not only to suppress tumor growth but also to reduce metastasis. Studies reported here focus on determining the toxicity of this drug in the nude mice. During the first study, treated animals (single intraperitoneal (ip) injection, 0, 40, 80 and 120 mg/kg body weight) were closely monitored for 14 days for any signs of illness or death. No mice were lost in any animal groups; however, hepatic serum enzymes were elevated, and hepatic and heart tissue damages were found in the highest dosage group. The subsequent study was performed using a lower dosage range (single ip injection, 0, 25, 50 and 75 mg/kg body weight), which resulted in no significant toxicity. All tested parameters were within normal ranges, with no observed irregularities. Our findings show that a single ip dose of this ceramide analog induced liver and heart toxicity at 120 mg/kg but not at doses of 80 mg/kg body weight or lower.

A new technique for precisely and accurately measuring lumbar spine bone mineral density in mice using clinical dual energy X-ray absorptiometry (DXA).

Dual Energy X-ray Absorptiometry (DXA) is effective in measuring bone mineral density (BMD) in mice for early detection of osteoporosis. However, scanners designed for use with small animals (i.e. PIXImus) are very expensive. Used human DXA machines are cheaper to obtain, but analysis of scans from these instruments is operator-dependent. Obtaining reliable data depends on having a single operator analyze the scans in a blinded fashion. Scan quality is improved by excising the bone prior to scanning, which does not allow serial measurements. This study describes a novel method of analyzing lumbar spine BMD in mice using whole body DXA. This non-invasive technique has a high degree of precision and reproducibility, with good correlation between multiple observers. Inter-observer variability (0.063 +/- 0.00317 g/cm(2) [mean +/- SD], 5.05 [% coefficient of variation (CV)], repeat scan variability (0.063 +/- 0.00364 g/cm(2) [mean +/- SD], 5.94 [%CV]) were very low compared to variability between different animals (0.063 +/- 0.00588 g/cm(2) [mean +/- SD], 9.64 [%CV]) and variability seen in same animal over time (0.011 +/- 0.00885 g/cm(2) [mean +/- SD], 80.68 [%CV]). The measurement error is thus smaller than the biological variation. Accuracy was determined by comparing average peak BMD from two scans per mouse in-vivo (0.066 g/cm(2)) versus excised spine (0.065 g/cm(2)). Furthermore, correlation between bone ash weights and whole body lumbar spine BMD measurements (p < 0.0001) was highly significant. This technique thus shows a high degree of precision and accuracy, even with multiple observers, for measuring BMD in mice using a DXA machine designed for clinical use.

A new technique for quantitative analysis of hair loss in mice using grayscale analysis.

Alopecia is a common form of hair loss which can occur in many different conditions, including male-pattern hair loss, polycystic ovarian syndrome, and alopecia areata. Alopecia can also occur as a side effect of chemotherapy in cancer patients. In this study, our goal was to develop a consistent and reliable method to quantify hair loss in mice, which will allow investigators to accurately assess and compare new therapeutic approaches for these various forms of alopecia. The method utilizes a standard gel imager to obtain and process images of mice, measuring the light absorption, which occurs in rough proportion to the amount of black (or gray) hair on the mouse. Data that has been quantified in this fashion can then be analyzed using standard statistical techniques (i.e., ANOVA, T-test). This methodology was tested in mouse models of chemotherapy-induced alopecia, alopecia areata and alopecia from waxing. In this report, the detailed protocol is presented for performing these measurements, including validation data from C57BL/6 and C3H/HeJ strains of mice. This new technique offers a number of advantages, including relative simplicity of application, reliance on equipment which is readily available in most research laboratories, and applying an objective, quantitative assessment which is more robust than subjective evaluations. Improvements in quantification of hair growth in mice will improve study of alopecia models and facilitate evaluation of promising new therapies in preclinical studies.

Assessment of male reproductive system in the CD-1 mice following oral manganese exposure.

Manganese has wide industrial applications and exposure to manganese can result in serious health conditions. The purpose of this study was to determine the reproductive effect of oral manganese exposure in male mice. Manganese acetate was tested at three dose levels (7.5, 15.0, and 30.0 mg/kg/day) for 43 days. The control group (0 mg/kg/day) received distilled water. Control negative group did not receive anything. Reproductive organ weights were recorded. Histopathology was performed on right testis, epididymis, seminal vesicle, and the accessory glands. Cauda epididymal, testicular sperm counts, and sperm motility was evaluated on the organ from the left side. The results of this study suggest that exposure to manganese caused a statistically significant (P<0.001) decrease in sperm motility and sperm counts at 15.0 and 30.0 mg/kg/day. There were no alterations in the fertility or pathology of the testicular tissue in the manganese-treated mice when compared with the controls.

Pharmacokinetics in rats of a long-acting human parathyroid hormone-collagen binding domain peptide construct.

The pharmacokinetics of a hybrid peptide consisting of the N-terminal biologically active region of human parathyroid hormone (PTH) linked to a collagen-binding domain (CBD) were evaluated in female Sprague-Dawley rats. The peptide, PTH-CBD, consists of the first 33 amino acids of PTH linked as an extension of the amino acid chain to the CBD peptide derived from ColH collagenase of Clostridium histolyticum. Serum concentrations arising from single dose administration by the subcutaneous and intravenous routes were compared with those measured following route-specific mole equivalent doses of PTH(1-34). Population-based modeling demonstrated similar systemic absorption kinetics and bioavailability for both peptides. Exposure to PTH-CBD was sixfold higher because of a systemic clearance of approximately 20% relative to PTH(1-34); however, these kinetics were consistent with more than 95% of a dose being eliminated from serum within 24 h. Results obtained support continued investigation of PTH-CBD as a bone-targeted anabolic agent for the treatment of postmenopausal osteoporosis.

Reversed seasonal variation in maternal vitamin D levels in southern Louisiana.

Vitamin D is critical in bone and mineral homeostasis, particularly in the prevention of rickets in children. Levels of vitamin D in cord blood were measured in a population from New Orleans as an index of maternal vitamin D status at the time of delivery. Cord blood samples from infants born during the summer and winter showed lower 25-hydroxyvitamin D levels compared with those from infants born during fall and spring, indicating an unusual pattern of seasonality where vitamin D levels were among the lowest in the season with the greatest sunlight. It is important to establish screening and supplementation guidelines based on observed regional trends and risk factors, in addition to considerations based on global recommendations.

A treatment trial of vitamin D supplementation in breast-fed infants: universal supplementation is not necessary for rickets prevention in Southern Louisiana.

This study was conducted to determine if vitamin D supplementation is required to prevent rickets in breast-fed infants. Breast-feeding rates are increasing, and there are concerns about whether the vitamin D content of breast milk is sufficient. There are a few treatment trials of vitamin D supplementation in breast-fed infants; these were conducted in northern climates. The authors therefore performed a prospective clinical trial comparing vitamin D supplementation with placebo as control in southern Louisiana. Blood samples and questionnaires were collected at birth, 2, 4, and 6 months of age. There were no cases of rickets observed, and no differences in alkaline phosphatase levels between groups. Thus, there was no evidence that vitamin D supplementation reduced rickets risk in the authors' study population. This suggests that the current recommendations for universal vitamin D supplementation of breast-fed infants throughout the United States may need to be revised.

Breastfeeding does not protect against urinary tract infection in the first 3 months of life, but vitamin D supplementation increases the risk by 76%.

Our goal was to determine if breastfeeding provides any protection against urinary tract infection (UTI) and if vitamin D supplementation imposes any additional risks for UTI in infants < 3 months of age. In this study, 40% of the children who had urine cultures were breastfed, and 18.7% of the children were exclusively breastfed. Twenty percent of all of the urine cultures tested positive, and this number was greater in females (22.5%) than in males (18.1%, P < .05). There was no significant difference between the rates of positive urine cultures in exclusively breastfed (22% vs 21%, nonsignificant [NS]) formula-fed infants. The relative risk of UTI with breastfeeding versus formula feeding was 1.03 (0.58-1.82), and any breastfeeding versus no breastfeeding was 0.92 (0.58-1.45). Vitamin D supplementation increased the UTI risk, with a relative risk of 1.76 (1.07-2.91, P < .05). However, only formula-fed infants showed an increased risk of UTI after vitamin D supplementation.