Extramammary Tissue Research Articles

Distinctive Lipogenic Gene Expression Patterns in the Mammary Glands of Dairy Cows Are Associated with the Unique Fatty Acid Composition of Bovine Milk Fat

Fat composition is largely responsible for the technological and rheological properties of cow milk and dairy products. Bovine milk fat is unique in terms of its fatty acid composition and positional distribution, with about 25% of its fatty acids being short- and medium-chain, which are synthesized de novo in the mammary gland and are not present in extra-mammary tissues. With the aim to identify potential genetic factors responsible for the unique composition of bovine milk fat, we extracted genes with GO annotations related to lipid metabolism and performed a gene expression mega-analysis. Overall, different lipogenic tissues (i.e., mammary, liver, and adipose) displayed discerned expression patterns. In a PCA, the liver was significantly separated from adipose and mammary tissues. In a correlation analysis with the fatty acid synthetase (FASN) gene, notable differences among the tissues were found. In the mammary gland, the majority of genes (~70%) were negatively correlated with FASN expression, whereas only 18% were negatively correlated in adipose. Only a few genes were positively correlated with FASN exclusively in the mammary gland, including AGPAT1 and AGPAT6, which also had the highest expression in the mammary gland compared with adipose. Looking at the expression levels in tissues (TPM) revealed significant differences in the expressions of genes responsible for the activation of fatty acids by ligation to CoA, according to their carbon chain length. Notably, the ACSS1 gene, which converts acetate to acetyl-CoA, had the highest expression in the mammary gland, whereas genes responsible for the activation of long-chain fatty acids had lower expressions. The findings of the present study suggest that the unique properties of dairy fat are the results of the distinct expression patterns of genes involved in de novo synthesis of fatty acids and their downstream utilization.

Review: Influence of postabsorptive metabolism on essential amino acid partitioning in lactating dairy cows

In the lactating cow, essential amino acids (EAAs) absorbed from the gut are partitioned to mammary and extra-mammary tissues via blood plasma circulation. There is also entry of EAA into plasma from the breakdown of proteins in the cow’s body. A balance model across plasma was solved to integrate entry rates of branched-chain (BCAA) and non-branched-chain EAA (NBAA) with their corresponding rate constants for clearance by mammary glands and the remainder of the body, for selected glucose and fat infusion experiments. Endogenous EAA entry from whole-body proteolysis was reduced by glucose and unchanged or increased by fat, the efficiency of net plasma BCAA clearance by mammary and extra-mammary tissues was elevated by glucose but slightly reduced by fat, and the efficiency of extra-mammary NBAA clearance may have decreased during glucose infusion but it was not affected or slightly increased by fat. These differences between glucose and fat responses can be accounted for by insulin and glucagon. Insulin suppresses endogenous EAA entry through mechanistic target of rapamycin complex 1, integrated stress response, and glycogen synthase kinase 3 signaling networks in skeletal muscle. While these networks can also regulate protein synthesis rates in muscle and the extra-mammary body, they exhibit low sensitivities to insulin in lactating ruminants. However, in the mammary glands, via these same networks, insulin stimulates clearance of EAA from plasma, although the drive to maintain a set point for milk protein yield takes precedence over nutritional signals. The glucose-induced increase in mammary BCAA clearance without an effect on NBAA clearance is due to a pronounced decrease in plasma BCAA concentrations. Because NBAAs do not experience a similar decline in concentration, the BCAA effect must be due to their metabolic transformation as opposed to sequestration in proteins. In adipose, the products of BCAA catabolism are lipogenic precursors. We propose that faster lipogenesis in adipose tissue, stimulated by glucose infusion, also promotes the uptake of precursor BCAA from plasma, causing a drop in their circulating concentrations. In addition, insulin stimulates BCAA oxidation in muscle as an alternative fuel to fatty acids. A lower efficiency of extra-mammary NBAA clearance during glucose infusion may be the consequence of decreased hepatic expression of AA-catabolizing enzymes in response to low glucagon concentration. The proportion of EAA entry partitioned to the mammary glands is a culmination of regulatory shifts at all of the points discussed above according to a regulated or unfair competition between mammary and extra-mammary processes.

Mitochondrial Bioenergetics of Extramammary Tissues in Lactating Dairy Cattle.

Simple SummaryThe nutrient and energy requirements of lactation are among the greatest required by any physiological process in the female mammal. The mammary gland and extramammary tissues undergo metabolic adaptations that coordinate changes in energy availability and nutrient partitioning that enable milk synthesis. Mitochondria are largely responsible for energy production in cells and their importance in milk synthesis has long been appreciated. However, mitochondrial adaptations across lactation are understudied, particularly for extramammary tissues with supporting roles in milk synthesis. Tracking mitochondrial function in dairy cattle across lactation, we found that the efficiency of energy production in the liver was elevated in the presence of fat-based substrates as the milk yield was increasing. In skeletal muscle, mitochondrial function showed little change across lactation and was not associated with milk production, suggesting that energy efficiency in this tissue is consistent regardless of the metabolic demands of lactation. A better understanding of mitochondrial bioenergetics during lactation may provide insight into the etiology of metabolic diseases during the transition period and low milk supply.Lactation is physiologically demanding, requiring increased nutrient and energy use. Mammary and extramammary tissues undergo metabolic changes for lactation. Although it has long been recognized that mitochondria play a critical role in lactation, the mitochondrial adaptations for milk synthesis in supporting tissues, such as liver and skeletal muscle are relatively understudied. In this study, we assessed the mitochondrial function in these tissues across lactation in dairy cattle. Tissue biopsies were taken at 8 ± 2 d (early, n = 11), 75 ± 4 d (peak, n = 11) and 199 ± 6 d (late, n = 11) in milk. Early lactation biopsies were harvested from one group of cows and the peak and late biopsies from a second cohort. Milk yield (MY) was recorded at each milking and milk samples were collected for composition analysis. Mitochondrial efficiency was quantified as the respiratory control ratio (RCR), comparing maximal to resting respiration rates. Liver complex II RCR was positively associated with MY. Liver ROS emission increased across lactation whereas liver antioxidant activity was similar across lactation. No change was detected in skeletal muscle RCR or ROS emission, but muscle GPx activity decreased across lactation and muscle SOD was negatively associated with MY. Muscle oxidative damage was elevated at early and late lactation. Across lactation, genes involved in mitochondrial biogenesis were upregulated in the liver. Our results indicate that during lactation, liver mitochondrial biogenesis and efficiency are increased, which is associated with greater milk yield. In contrast, the mitochondrial efficiency in skeletal muscle remains consistent across lactation, but undergoes oxidative damage, which is associated with reduced antioxidant activity.

An unusual case of synovial sarcoma with breast metastasis: Findings on positron emission tomography-computed tomography

Synovial sarcomas are aggressive soft-tissue tumors with the propensity for metastases at presentation or later course of disease. The most common site of metastases is lung, followed by lymph node and bone. It rarely metastasizes to the liver and to the brain. Breast metastases from extramammary tissue are extremely rare, more so from synovial sarcoma. 18F-fluorodeoxyglucose positron emission tomography–computed tomography (FDG PET/CT) plays a very important role in diagnosing occult metastasis in sarcomas. Histopathological diagnosis and translocation studies are important to confirm the diagnosis. We present a case of synovial sarcoma who underwent 18FDG PET/CT which showed occult metastasis to the breast.

Short communication: The effect of increasing concentrations of different methionine forms and 2-hydroxy-4-(methylthio)butanoic acid on genes controlling methionine metabolism in primary bovine neonatal hepatocytes

The d-isomer of Met cannot be used directly by the mammary gland in dairy cows; instead, it is transformed into l-Met, the proteogenic isomer, in the liver and other extramammary tissues. It remains unclear whether different Met forms and a Met hydroxy analog, 2-hydroxy-4-(methylthio)butanoic acid (HMB), are metabolized and function similarly in the liver. The objective of the present study was to examine the regulation of key genes in Met regeneration, transulfuration, and transmethylation pathways in response to increasing doses of different Met forms. Hepatocytes isolated from 4 calves between 4 and 7 d old were maintained as monolayer cultures for 24 h before addition of treatments. Treatments of (0, 10, 20, 40 µM) d-Met, l-Met, dl-Met, dl-HMB, or a 1:1 mixture of dl-Met and dl-HMB were added to Met-free medium in triplicate. After 24 h, cell lysates were collected for quantification of gene expression by quantitative PCR, and mRNA abundance was normalized to the mean of 3 reference genes. Data were analyzed with PROC MIXED of SAS 9.3 (SAS Institute Inc., Cary, NC). Analyses of covariance confirmed equivalent slopes of Met form, and the final model included form, dose, and random effect of calf within form. Data are reported as least squares means ± standard error. No main effect of Met form was observed for any genes examined. The enzymes encoded by betaine-homocysteine methyltransferase (BHMT) and 5-methyltetrahydrofolate-homocysteine methyltransferase use betaine and 5-methyltetrahydrofolate, respectively, to regenerate Met from homocysteine. Increasing concentration of Met did not alter 5-methyltetrahydrofolate expression, but decreased BHMT expression. Expression of glycine N-methyltransferase, the enzyme that controls transmethylation flux from S-adenosyl-methionine, was not affected by Met concentration. Methionine concentration had no effect on expression of cystathionine β-synthase, a key enzyme for the transulfuration pathway. The decrease in BHMT expression indicates a decreased need for cellular Met regeneration with increasing Met concentration, independent of Met form. The lack of differences among Met forms on regulating genes examined indicates that all Met forms similarly reduced genes controlling Met regeneration and metabolism in primary bovine hepatocytes.

18F-FDG PET/CT detects Metastatic Renal Cell Carcinoma Masquerading as Primary Breast Malignancy.

We present the case of a 36-year-old woman who underwent 18F-FDG PET/CT with suspicion of a primary breast malignancy. However, PET/CT detected an occult renal cell carcinoma with metastases to the thyroid, breast, lungs and lymph nodes. Thyroid and breast metastases are atypical metastatic sites of renal cell carcinoma. Breast metastases from extra mammary tissue are extremely rare, more so from renal cell carcinoma. Histopathologic confirmation of the breast lesions is imperative to avoid unnecessary mastectomy and imaging can help in raising the suspicion of metastatic involvement versus primary breast malignancy.

Maintenance of plasma branched-chain amino acid concentrations during glucose infusion directs essential amino acids to extra-mammary tissues in lactating dairy cows

The objectives of this study were to investigate the effects of branched-chain AA (BCAA) supplementation when glucose is infused postruminally into lactating dairy cows consuming a diet low in crude protein (CP) and to test the hypothesis that low BCAA concentrations are responsible for the poor stimulation of milk protein yield by glucose. Twelve early-lactation Holstein cows were randomly assigned to 15% and 12% CP diets in a switchback design of 6-wk periods. Cows consuming the 12% CP diet received 96-h continuous jugular infusions of saline and 1 kg/d of glucose with 0, 75, or 150 g/d of BCAA in a Latin square sequence of treatments. Compared with saline, glucose infusion did not affect dry matter intake but increased milk yield by 2.2 kg/d and milk protein and lactose yields by 63 and 151 g/d, respectively. Mammary plasma flow increased 36% during glucose infusion compared with saline infusion, possibly because of a 31% decrease in total acetate plus β-hydroxybutyrate concentrations. Circulating concentrations of total essential AA and BCAA decreased 19 and 31%, respectively, during infusion of glucose, yet net mammary uptakes of AA remained unchanged compared with saline infusion. The addition of 75 and 150 g/d of BCAA to glucose infusions increased arterial concentrations of BCAA to 106 and 149%, respectively, of the concentrations in saline-infused cows, but caused a decrease in concentrations of non-branched-chain essential AA in plasma, as well as their mammary uptakes and milk protein yields. Plasma urea concentration was not affected by BCAA infusion, indicating no change in catabolism of AA. The lack of mammary and catabolic effects leads us to suggest that BCAA exerted their effects on plasma concentrations of the other essential AA by stimulating utilization in skeletal muscle for protein accretion. Results indicate that the glucose effect on milk protein yield was not limited by low BCAA concentrations, and that a stimulation of extra-mammary use of non-branched-chain essential amino acids by BCAA led to a decrease in milk protein yield.

Glucose supplementation stimulates peripheral branched-chain amino acid catabolism in lactating dairy cows during essential amino acid infusions

To determine how glucose modulates protein synthesis when essential AA are in abundant supply, 5 early-lactation, rumen-fistulated Holstein dairy cows were fed a diet containing 6.95 MJ/kg of net energy for lactation and 12.4% crude protein and abomasally infused for 5d with saline, 844 or 1,126g/d of a complete essential AA mix, with and without the inclusion of 1,000g/d of glucose, in a 5×5 Latin square design. Infusion of essential AA increased milk yield by 4.1kg/d, milk protein by 256g/d, milk fat by 95g/d, and milk urea nitrogen by 70% compared with saline, with no differences between the level of essential AA infusion. The addition of glucose to essential AA infusate did not stimulate milk protein yield or concentration, but reduced milk urea nitrogen by 17% and decreased milk fat yield. Arterial concentrations of total essential AA increased 3- to 4-fold, mammary clearance decreased 61%, and mammary uptake of essential AA increased 65% in response to essential AA infusion. Arterial branched-chain AA concentrations declined 29% in response to glucose and mammary clearance increased 48%, but mammary AA uptake was unchanged. Essential AA infusion increased plasma 3-methylhistidine by 50% and reduced muscle branched-chain α-keto acid dehydrogenase kinase abundance by 14%, indicating stimulation of muscle protein turnover and branched-chain AA catabolism, respectively. Glucose had no further effect on muscle branched-chain α-keto acid dehydrogenase kinase abundance but decreased mRNA expression of branched chain aminotransferase 1. Lack of further increases in plasma 3-methylhistidine or greater stimulation of muscle branched-chain AA catabolism indicates that muscle protein degradation was unchanged with glucose but that accretion may have been stimulated. The decrease in circulating branched-chain AA concentrations and nitrogen excretion in response to glucose suggests that surplus essential AA were redirected to peripheral, extra-mammary tissues.

Lactational Ectopic Breast Tissue of the Vulva: Case Report and Brief Historical Review

Ectopic breast tissue is defined as glands of breast tissue located outside of the normal anatomic breasts. Historically, ectopic breast tissue has been thought to arise from a remnant of the embryonic mammary ridge along the "milk line" or the midaxillary line from the axilla to the groin, including the vulvar region. Extramammary tissue displays the same pathologic and physiologic changes as normal breast tissue and is often discovered in multiparous women as the result of swelling from lactational activity. We present a case report of a gravid patient with lactating vulvar mass and a brief historical perspective of vulvar ectopic breast tissue.

Metastatic endometrial endometrioid carcinoma with clear cell changes to the breast: a case report

Metastasis to breast from extramammary tissue is rare, and endometrial cancer has rarely been reported to metastasize to the breast. An extensive search in the medical literature reveals only 2 cases. They can be easily mistaken for primary breast carcinoma both clinically and radiologically, even with known history of endometrial carcinoma. This report presents a case of a 64-year-old woman who had endometrial carcinoma treated with total hysterectomy and adjuvant radiation and chemotherapy. Three years after the diagnosis, she had evidence of a solitary breast metastasis. To our knowledge, this is the third described case of endometrial cancer metastatic to the breast and the first in which the endometrial carcinoma demonstrates significant clear cell changes. This report is a reminder that although rare, endometrial carcinoma has the potential to metastasize to breast and illustrates how metastatic lesions in the breast can masquerade clinically as a primary carcinoma. Furthermore, essential guidelines necessary to distinguish primary from metastatic lesions in the breast are presented.

Ectopic Breast Fibroadenoma of the Vulva

Ectopic breast (extramammary) fibroadenomas of the vulva are rare, cosmetically disfiguring, and very difficult to distinguish from other labial masses on physical examination. Extramammary tissue is susceptible to similar benign and malignant changes seen in the breast. Some patients with ectopic breast lesions may harbor an underlying urinary tract anomaly. We report a case of a young woman who presented with an unknown progressively enlarging mass in the vulva. The mass was excised completely in a cosmetic manner and histology demonstrated an ectopic breast fibroadenoma. Clinicians should include extramammary lesions in their preoperative differential diagnosis of vulvar masses since some may become neoplastic. Treatment is complete excision and renal imaging should be considered after a confirmed histopathologic diagnosis.

Cell biology of the movement of breast cancer cells: Intracellular signalling and the actin cytoskeleton

Cell motility is a critical step in cancer invasion and metastasis that must be unravelled to gain an appropriate understanding of the behaviour of cancer cells. A broad spectrum of motility mechanisms that facilitate invasion of extramammary tissues and metastasis exists in breast cancer cells (e.g. reorganization of the actin cytoskeleton, regulation of focal adhesion, changes in response to a different microenvironment, epithelial mesenchymal transition, and control of membrane proteins through endocytosis). These cellular responses are tightly regulated by intracellular signalling pathways evoked by humoral factors that include growth factors, chemokines, and cytokines. Learning more about the cellular and molecular basis of these different motility programmes will aid in the development of treatments for breast cancer invasion and metastasis. This review of recent literature focuses on aspects of cell biology related to motility and metastasis, and suggests some directions for future breast cancer research.

Invasive cribriform carcinoma with extensive microcalcifications in the male breast

Invasive cribriform carcinoma (ICC) is a rare, unique type of invasive breast carcinoma that exhibits a cribriform pattern in the majority of the invasive component and is associated with an excellent prognosis. Only one male patient with ICC has been previously reported. Mammography studies often suggest that ICC contains microcalcifications, but the histological finding of extensive microcalcification has only been reported in one patient with ICC. Here we report a male patient diagnosed with ICC and exhibiting histologically confirmed extensive microcalcification is reported. The patient was a 64-year-old Japanese man in whom a breast tumor was detected during an annual check up. Mammography demonstrated a circumscribed high-density mass with microcalcifications. Breast-conserving surgery with axillary node dissection was performed. The tumor was located in the subareolar region of his left breast. The excised tumor had a maximum diameter of 1.0 cm, and no signs of invasion to extramammary tissue were observed. Histologically, the tumor cells were arranged in a cribriform pattern with invasive and non-invasive components. High-grade carcinoma or tubular carcinoma components were not observed. Extensive calcification was seen within the cribriform spaces. Immunohistological staining revealed that the cribriform spaces did not contain basement membrane material, and the tumor cells had not differentiated into basaloid cells or lactational mammary epithelium. The patient is presently free from local recurrence or metastasis 7 months after undergoing surgery.

Methionine Flux and Tissue Protein Synthesis in Lactating and Dry Goats

Whole-body methionine flux (rate of irreversible loss from plasma) and tissue protein synthesis were estimated in dry and early lactating goats (10-14 d postpartum) by intravenous infusion of L-[35S]methionine. Tissue protein mass was significantly (p less than 0.05) higher for mammary gland and liver but lower for carcass in lactating animals. The plasma methionine flux was higher during lactation (8.5 vs. 5.1 g/d). The fractional synthesis rates of tissue proteins (Ksp: %/d) were lower during lactation for some muscles, especially the masseter muscle (1.46 vs. 2.15), and for skin (0.59 vs. 1.22) and the pooled head plus feet fraction (1.64 vs. 2.31), but the rates were greatly increased in mammary gland (42 vs. 3). The non-mammary methionine flux (plasma flux minus the flux corresponding to milk methionine output and methionine utilization for mammary protein synthesis) was significantly (p less than 0.05) lower for the lactating goats than for the dry group (93 vs. 131 mg.d-1.kg empty body weight-1). This is in agreement with the lower rates of protein synthesis in carcass (542 vs. 948 mg.d-1.kg empty body weight-1) and skin (93 vs. 189) for lactating compared to dry goats. It can be inferred from these data that in early lactation, when nutrient requirements of animals are not adequately met, an adaptative mechanism occurs that allows amino acids to be available for the mammary gland by a decrease of their utilization in some extramammary tissues.

Axillary Extra Mammary Tissue

To the Editor.— The medical therapy advocated by gynecologist Altchek for the 15-year-old girl with a unilateral axillary is a brilliant synopsis of the present-day thoughts on breast swelling and the factors involved in fibrocystic disease of the breast. However, this child, who is obviously uncomfortable and upset because of a unilateral mass in the axilla, should not begin a multiplicity of semiproved therapies that last until menopause, including many with severe and possible long-term systemic effects. It is amazing to note six paragraphs, including one on diet restriction, full of current hypothetical modalities that have little reference to the present axillary tissue problem and but one brief sentence stating that rarely, surgical excision is considered if the axillary mammary tissue is large or physically or emotionally disturbing. There is a simple procedure performed by plastic surgeons with few, if any, complications that can be applied to enlarged

Axillary Extra Mammary Tissue

To Editor.— I believe that MD, New York and his 15-year-old patient who complained of extramammary breast in axilla are entitled to an additional opinion. The one offered in The Journal suffers from the misleading generalizations and unconscious prejudice referred to by Spodick in his quotation from Science and Common Sense by James Bryant Conant in same issue (1982;247:2258). The Olympian opinion offered to this poor adolescent girl included avoidance of salt and monosodium glutamate; avoidance of caffeine, tea, cola drinks, chocolate, and cocoa. In addition, she is to take vitamin B complex and vitamin E capsules. She is to wear a bra not only to support breasts, but also breast in axilla. How this latter maneuver is to be accomplished is left up to ingenuity of inquiring physician and his patient. The consultant also recommended to avoid tight

Axillary extra mammary tissue

Axillary extra mammary tissue

Axillary Extra Mammary Tissue

To the Editor.— I must take strong issue with the answer that was given to the physician who inquired about the treatment of axillary breast tissue in a teenage girl (1982;247:2301-2302). I believe the answer given shows a complete lack of understanding and/or empathy and typifies the depersonalization of medicine often, seen today. Axillary breast tissue is an embarrassment to the girl who has it. It limits her selection of clothes and her activity. The consultant suggested severe dietary restrictions. If you limit the clothing, activity, and food of a teenage girl, you have essentially deprived her of all facets of her social activities. The treatment is to remove this extraneous breast tissue. This can be done through relatively inconspicuous axillary incisions under general or local anesthesia. There is an excellent discussion of this problem and its treatment available. 1